The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

The development and validation of a scoring tool to predict the operative duration of elective... Background The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utili- sation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p < 0.001), with the proportions of operations lasting > 90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care. Keywords Laparoscopic cholecystectomy · Patient factors · Operative duration · Scoring tool · Prediction · Theatre utilisation There are 70,000 cholecystectomies performed in the UK each year, making it one of the most common general sur- gical operations [1]. The average operative duration for * Ewen Griffiths this laparoscopic procedure is usually < 1 h [2]. With the ewen.griffiths@uhb.nhs.uk average hourly cost for an operating theatre being £1200, efforts to utilise every minute of allocated theatre time is College of Medical & Dental Sciences, University of Birmingham, Birmingham, UK vital [3]. This is especially so in a resource constrained National Health Service (NHS) working environment that Institute of Translational Medicine, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK is required to save £20 bn by 2020 to remain sustainable for the future [4]. Poor planning can lead to cancellations, Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, which are expensive for the Trust and, more importantly, Birmingham, UK distressing for patients. One particular study found that 63% Department of Upper Gastrointestinal Surgery, University of on-the-day cancellations were due to a lack of theatre time Hospitals Birmingham NHS Foundation Trust, Birmingham, [5], with another study demonstrating that approximately UK Vol.:(0123456789) 1 3 3150 Surgical Endoscopy (2018) 32:3149–3157 30% of lists are under-run, leaving the operating theatre idle (N = 5), as these were thought to be unrealistic. This left a [6]. Careful planning and scheduling is therefore paramount total of 7227 patients for analysis. to increase operating theatre efficiency and, in doing so, it is estimated that NHS trusts can make efficiency savings Validation dataset of approximately £4 m per year [3]. In a time where ris- ing demographic pressures are demanding ever increasing The validation dataset was retrospectively collected from the spending on healthcare, it is vital we optimise the use of our University Hospitals Birmingham NHS Foundation Trust existing resources. (UHB)—a large tertiary hospital with 1213 inpatient beds Previous research in other surgical areas has assessed a and 32 operating theatres [16]. Data were collected for all variety of patient factors and their impact on operative dura- elective laparoscopic cholecystectomies carried out between tion [7–11], but studies in laparoscopic cholecystectomy are 2010 and 2016, excluding emergencies, as well as those few and a predictive scoring tool is yet to be developed. Tra- having combined procedures. This left a total of N = 2405 ditionally, surgeons have estimated their operative durations, patients for analysis. Data for surgical duration and pre- but research has demonstrated that these estimates are often operative factors were gathered from a variety of electronic inaccurate [6]. Many hospitals have now moved to electronic hospital systems, including the Lorenzo patient information systems and central schedulers with the aim of reducing system, Galaxy operating theatre system and PICS (Prescrib- costs. However, such systems require significant learning ing Information and Communication system). ASA grades time to adapt to organisational needs [12]. Historical proce- were calculated using comorbidities derived from the infor- dure and surgeon data have been used to estimate operative matics database, and were based on the definitions provided duration. However, this is known to be of low accuracy, as it by the American Society of Anaesthesiologists [17]. fails to account for pre-operative patient factors [12]. We aimed to create a clinically useful scoring tool to pre- Statistical methods dict the operative duration of laparoscopic cholecystectomy using pre-operative patient factors and to externally validate Initially, the operative duration was dichotomised into its reliability using a separate dataset. groups of ≤ 90 vs. > 90  min. Univariable analyses were then performed, comparing the rates of operative durations > 90 min across a range of factors. Comparisons across cat- egorical factors were made using Fisher’s exact tests, whilst Methods Mann–Whitney tests were used to compare ordinal factors between the operative duration groups. Two datasets were used in this study, to allow for a risk score A multivariable analysis was then performed to identify to be produced and externally validated: independent predictors of operative duration. A binary logis- tic regression model was produced, with a forwards stepwise CholeS dataset approach used to select variables for inclusion. The resulting model was then converted to a risk score, by rounding the The CholeS study was a multicentre, prospective popula- beta coefficient (log-odds) of each factor to the nearest 0.5, tion-based cohort study that assessed variations in patient after multiplying by a constant to minimise the impact of factors with outcomes of cholecystectomy [13, 14]. The rounding errors. Where this resulted in negative values, the protocol for this study has been published previously [15]. reference category was changed, such that all values in the Data were collected from 8820 patients who underwent a score were positive. The predictive accuracy of the model laparoscopic cholecystectomy at 166 hospitals in the UK was then assessed using ROC curves. The model was also between March to April 2014, and was found to be 99.2% applied to a second cohort of patients for external validation. accurate by independent data validation. Pre-operative vari- All analyses were performed using IBM SPSS 22 (IBM ables included patient demographics, indications for surgery, Corp. Armonk, NY), with p < 0.05 deemed to be indicative admission type, ASA grade, ultrasound findings and pre- of statistical significance throughout. operative ERCP. Surgical duration was calculated from the time (minutes) of skin incision to end of skin closure. For this study, all patients undergoing emergency chol- Results ecystectomy were excluded (N = 1420), as these are associ- ated with long procedure times and elective theatre utilisa- Demographics tion was the focus of this study. In addition, those where the operative duration was not recorded (N = 168) were After exclusions, data were available for 7227 surgeries in excluded, as were those with an operative duration < 10 min the derivation (CholeS) cohort. The patients had a mean 1 3 Surgical Endoscopy (2018) 32:3149–3157 3151 Table 1 Univariable analysis of associations between operative dura- Table 1 (continued) tion and both demographic and pre-operative factors N Operative p Value dura- N Operative p Value tion > 90 min dura- tion > 90 min  >2 170 57 (33.5%) Age (years) < 0.001** ASA < 0.001*  < 30 854 90 (10.5%)  1 2803 352 (12.6%)  30–39 1035 128 (12.4%)  2 3687 722 (19.6%)  40–49 1397 237 (17.0%)  >2 690 199 (28.8%)  50–59 1534 297 (19.4%) Data reported as N (%), with p values from Fisher’s exact tests, unless  60–69 1381 282 (20.4%) stated otherwise  70+ 1023 245 (23.9%) *p Value from a Mann–Whitney test, to account for the ordinal nature Gender < 0.001 of the factor  Female 5406 852 (15.8%) **p Value from a Mann–Whitney test, using the exact age. Bold p  Male 1821 427 (23.4%) values are significant at p < 0.05 Indication for surgery < 0.001  Acalculous/cholecystitis 1739 483 (27.8%) age of 51 years (SD = 16), and the majority were female  CBD stone 479 145 (30.3%) (74.8%). The median operative duration was 60 min, with  Colic/dyskinesia/polyp 4435 541 (12.2%) an interquartile range (IQR) of 45–85 min. Operations lasted  Pancreatitis 570 109 (19.1%) for > 90 min in 17.7% (N = 1279) of the cohort. BMI < 0.001*  <25 1475 219 (14.8%) Risk score derivation  25–30 2465 424 (17.2%)  31–35 1689 305 (18.1%) Associations between the operative duration and a range  >35 1324 279 (21.1%) of demographic and pre-operative factors are reported in CBD diameter < 0.001 Table 1. All of the factors considered were found to be sig-  Normal 6013 936 (15.6%) nificantly associated with longer operative durations. For  Dilated 1063 310 (29.2%) this reason, a multivariable analysis was performed, in order Gallbladder wall < 0.001 to identify which factors were independently associated  Normal 5017 708 (14.1%) with operative duration (Table 2). This analysis found the  Thick walled 2053 530 (25.8%) likelihood of an operation taking > 90 min to increase sig- Pre-operative MRCP < 0.001 nificantly with BMI (p < 0.001), ASA grade (p < 0.001), and  No 5325 857 (16.1%) the number of previous surgical admissions that the patient  Yes 1819 419 (23.0%) had (p = 0.005). In addition, the indication on admission Pre-operative CT < 0.001 significantly influenced operative duration (p < 0.001), with  No 6158 1006 (16.3%) patients admitted with acalculous and cholecystitis being  Yes 978 271 (27.7%) the most likely to have operations lasting > 90 min. Patients Pre-operative ERCP < 0.001 with a thickened gallbladder, a dilated CBD diameter, or  No 6349 1049 (16.5%) who had received a pre-operative CT or planned intra-oper-  Yes 783 227 (29.0%) ative cholangiogram were significantly more likely to take Grade of senior surgeon 0.005* > 90 min (all p < 0.001). In addition, patients of male gender  <ST5 308 42 (13.6%) (p = 0.002) and aged 40+ (p = 0.004) were also at signifi-  >ST6 1165 183 (15.7%) cantly higher risk of requiring a longer operative duration.  Consultant 5748 1052 (18.3%) These 10 factors were then combined to form a risk score Planned intra-op cholangiogram < 0.001 (Table  3). This score has a potential range from 0 to 20,  No 6519 1070 (16.4%) although the observed range in the cohort was 0.5–17.5  Yes 655 203 (31.0%) (median = 5). A ROC curve analysis returned an area under Number of previous surgical < 0.001* admissions the curve (AUROC) of 0.696 (SE = 0.009, p < 0.001) for the  0 4006 535 (13.4%) prediction of operations lasting > 90 min.  1 2424 546 (22.5%)  2 486 118 (24.3%) 1 3 3152 Surgical Endoscopy (2018) 32:3149–3157 Table 2 Multivariable analysis a Beta Odds ratio (95% CI) p Value of predictors of > 90 min operations Age (years) 0.004  <30 0 1 –  30–39 0.058 1.06 (0.78–1.45) 0.714  40–49 0.430 1.54 (1.16–2.05) 0.003  50–59 0.438 1.55 (1.17–2.06) 0.002  60–69 0.366 1.44 (1.07–1.93) 0.015  70+ 0.380 1.46 (1.07–2.00) 0.017 Gender (male) 0.241 1.27 (1.09–1.48) 0.002 Indication < 0.001  Acalculous/cholecystitis 0 1 –  CBD stone − 0.154 0.86 (0.66–1.12) 0.258  Colic/dyskinesia/polyp − 0.527 0.59 (0.49–0.71) < 0.001  Pancreatitis − 0.627 0.53 (0.41–0.70) < 0.001 BMI < 0.001  <25 0 1 –  25–30 0.208 1.23 (1.01–1.49) 0.035  31–35 0.291 1.34 (1.09–1.65) 0.006  >35 0.532 1.70 (1.36–2.13) < 0.001 CBD diameter (dilated) 0.535 1.71 (1.42–2.05) < 0.001 Gallbladder wall (thick) 0.371 1.45 (1.24–1.70) < 0.001 Pre-operative CT 0.320 1.38 (1.15–1.65) < 0.001 Planned intra-op cholangiogram 0.706 2.03 (1.66–2.47) < 0.001 Number of previous surgical admissions 0.005  0 0 1 –  1 0.202 1.22 (1.03–1.45) 0.020  2 0.227 1.25 (0.96–1.64) 0.095  >2 0.630 1.88 (1.29–2.74) 0.001 ASA < 0.001  1 0 1 –  2 0.225 1.25 (1.06–1.47) 0.007  >2 0.630 1.88 (1.48–2.39) < 0.001 Results are from a multivariable binary logistic regression model with a forward stepwise approach to vari- able selection. All factors from Table 1 were considered for inclusion in the model. Bold p values are sig- nificant at p < 0.05 The beta coefficients (i.e. log-odds) from the model Validation Discussion The risk score was then applied to a cohort of N = 2405 Our study has created a scoring tool that uses pre-operative patients from UHB for external validation. This cohort had patient factors to predict the probability that a laparoscopic a similar operative duration to the derivation cohort, with a cholecystectomy will take > 90 min. This scoring tool has median of 66 min (IQR: 52–85), and with 20.0% (N = 481) also been successfully externally validated against a sepa- of operations taking > 90 min. The median risk score was rate dataset and has demonstrated predictive accuracy. The found to be 4.5, with a range from 0 to 14.5. The score as results showed that, for low-scoring individuals vs. high- a whole had a similar degree of predictive accuracy to that scoring individuals, the proportion of operations taking observed in the derivation cohort, with an AUROC of 0.708 > 90 min increases significantly from 5.8 to 41.4%. (SE = 0.013, p < 0.001) (Fig. 1). We hope this scoring tool could enable better plan- ning and utilisation of elective theatre lists. A better 1 3 Surgical Endoscopy (2018) 32:3149–3157 3153 Table 3 Risk score Points Age (years)  <40 0  40+ 1.5 Gender (male)  Female 0  Male 1 Indication  Pancreatitis 0  Colic/dyskinesia/polyp 0.5  CBD stone 2  Acalculous/cholecystitis 2.5 BMI Fig. 1 Demonstrates the relationship between the risk score and the  <25 0 proportion of operations taking > 90 min in the validation cohort. Of  25–35 1 the 470 patients with risk scores of 0–3, only 5.1% (N = 24) of opera-  >35 2 tions took > 90 min, increasing to 41.8% (109/261) in those with risk CBD diameter scores > 8  Normal 0  Dilated 2 Gallbladder wall possible, given that laparoscopic cholecystectomies are one  Normal 0 of the most commonly performed operations in the NHS [1].  Thick 1.5 Thiels et al. [12] assessed the surgical duration of 1801 Pre-operative CT elective laparoscopic cholecystectomies from 2007 to 2013  No 0 and found female sex, BMI, ASA grade and pre-operative  Yes 1.5 laboratory results to be predictive factors in influencing Planned intra-op cholangiogram operative duration. They used a large group of patients  No 0 from the NSQIP (American College of Surgeons National  Yes 3 Surgical Quality Improvement Program) to validate their Number of previous surgical admissions findings [12]. Zdichavsky et al. [20] performed a retrospec-  0 0 tive analysis of 677 consecutive patients undergoing lapa-  1–2 1 roscopic cholecystectomies from 2004 to 2007 (excluding  >2 2.5 conversions, intra-operative cholangiogram and concurrent ASA liver cirrhosis) and found male sex, obesity, acute cholecys-  1 0 titis and previous abdominal surgery to be independently  2 1 predictive of duration. In a small study of only 138 chol-  >2 2.5 ecystectomies, junior residents took significantly longer to complete a cholecystectomy than their senior counterparts Based on the multivariable analysis in Table 2. The number of points (p < 0.05) [21]. for each factor was calculated by rounding the beta coefficient to the nearest 0.5, after multiplying by 4 to minimise rounding errors. Cat- In our study, factors found to be independently predictive egories for a factor that had the same number of points (e.g. age < 30 of operative duration were patient age, gender, ASA grade, and 30–39) were combined to simplify the table operative indication, BMI, CBD diameter, gallbladder wall thickness, pre-operative CT scan, planned intra-operative understanding of patient factors that result in increased cholangiogram and the number of previous surgical admis- operative duration and how this affects surgeon workload sions. These factors are broadly similar to previous work by can help to optimise theatre scheduling and result in fewer other researchers [12, 20, 21]. Our study expands on their cancellations. With theatres being one of the most expensive work and has developed a clinically useful scoring tool. To resources to run [18], even small improvements in theatre our knowledge, this is the first study to use patient factors to utilisation have the potential to impact costs greatly, and create a validated scoring tool to predict operative duration with many trusts under pressure to tackle unsustainable for elective laparoscopic cholecystectomies. deficits [ 19], it is possible that utilising this scoring tool Our study uses high-quality, validated, prospective may be helpful in addressing this issue. This is particularly data that were collected as part of the CholeS study. The 1 3 3154 Surgical Endoscopy (2018) 32:3149–3157 Sandro Pasquali, Surgical trainee, Surgical Oncology Unit, Veneto substantial cohort of 7227 patients is considerably larger Institute of Oncology IOV-IRCCS, Padova, Italy; than those used by past researchers, which altogether gives Paul Marriott, Surgical trainee, West Midlands Research Collabora- greater assurance as to the reliability of the derived scoring tive, Academic Department of Surgery, The University of Birmingham, tool. In addition, we have external validated our scoring tool Birmingham, UK; Marianne Johnstone, Surgical trainee, West Midlands Research and its utility to successfully predict operative duration. Our Collaborative, Academic Department of Surgery, The University of scoring tool can be used pre-operatively and was developed Birmingham, Birmingham, UK; in a dataset which included patients who underwent conver- Philip Spreadborough, Surgical trainee, West Midlands Research sion to open surgery and cholangiography and is therefore Collaborative, Academic Department of Surgery, The University of Birmingham, Birmingham, UK more generalizable. There are however some limitations that Derek Alderson, Emeritus Professor of Surgery, Academic Depart- should be considered when analysing this study’s results. ment of Surgery, The University of Birmingham, Birmingham, UK; The CholeS study did not collect data on pre-operative Ewen A. Griffiths, Consultant Surgeon, Department of Upper Gas- blood results, such as white cell count or CRP, or whether trointestinal Surgery, University Hospitals Birmingham NHS Founda- tion Trust, Birmingham, UK the patient had previous Upper GI surgery, which may indi- CholeS Study Collaborators: cate difficult surgery [22]. We recognise that the validation England—Stephen Fenwick, Mohamed Elmasry, Quentin M. dataset was retrospectively collected from routine hospital Nunes, David Kennedy (Aintree University Hospital NHS Foundation data and therefore may have some inaccuracies. ASA grades Trust); Raja Basit Khan, Muhammad A. S. Khan (Airedale General Hospital); Conor J. Magee, Steven M. Jones, Denise Mason, Ciny P. were calculated retrospectively based on information from Parappally (Wirral University Teaching Hospital); Pawan Mathur, the patients’ clinical records. However, even when ASA is Michael Saunders, Sara Jamel, Samer Ul Haque, Sara Zafar (Barnet calculated by anaesthetists there is an element of bias and and Chase Farm Hospital); Muhammad Hanif Shiwani, Nehemiah variation [23]. Furthermore, this scoring tool has been devel- Samuel, Farooq Dar, Andrew Jackson (Barnsley District General Hos- pital); Bryony Lovett, Shiva Dindyal, Hannah Winter, Ted Fletcher, oped for elective cholecystectomy data and should not be Saquib Rahman (Basildon Univesity Hospital); Kevin Wheatley, Tom used to predict the duration of acute operations. Nieto, Soofiyah Ayaani (Sandwell and West Birmingham Hospitals NHS Trust); Haney Youssef, Rajwinder S. Nijjar, Helen Watkin, David Naumann, Sophie Emesih; Piyush B. Sarmah, Kathryn Lee, Nikita Joji, Joel Lambert (Heart of England Foundation NHS Trust); Jonathan Heath, Rebecca L. Teasdale, Chamindri Weerasinghe (Blackpool Conclusion Teaching Hospitals NHS Foundation Trust); Paul J. Needham, Hannah Welbourn, Luke Forster, David Finch (Bradford Teaching Hospitals We have created a scoring tool to predict operative dura- NHS Foundation Trust); Jane M. Blazeby, William Robb, Angus G. K. McNair, Alex Hrycaiczuk (University Hospitals Bristol NHS Trust); tions of elective laparoscopic cholecystectomies using pre- Alexandros Charalabopoulos, Sritharan Kadirkamanathan, Cheuk- operative patient factors. Whilst previous research may Bong Tang, Naga V. G. Jayanthi, Nigel Noor (Broomfield Hospital); have examined the significance of individual factors, there Brian Dobbins, Andrew J. Cockbain, April Nilsen-Nunn, Jonathan de remained a lack of a formal scoring tool. Using the 7227 Siqueira (Calderdale and Huddersfield NHS Trust); Mike Pellen, Jona- than B. Cowley, Wei-Min Ho, Victor Miu (Hull and East Yorkshire patient CholeS dataset to derive the scoring system, and NHS Trust); Timothy J. White, Kathryn A. Hodgkins, Alison Kinghorn a UHB database of 2405 patients to subsequently validate (Chesterfield Royal Hospital NHS Foundation Trust); Matthew G. Tut- the tool, we have shown that it is possible to predict opera- ton, Yahya A. Al-Abed, Donald Menzies, Anwar Ahmad, Joanna Reed, tions that are likely to last greater than 90 min. This could Shabuddin Khan (Colchester Hospital University NHS Foundation Trust); David Monk, Louis J. Vitone, Ghulam Murtaza, Abraham Joel be useful for theatre schedulers to ensure theatre lists are (Countess of Chester NHS Foundation Trust); Stephen Brennan, David planned appropriately to optimise theatre utilisation and Shier, Catherine Zhang, Thusidaran Yoganathan (Croydon Health Ser- achieve cost savings. For example, the tool could be used vices NHS Trust); Steven J. Robinson, Iain J. D. McCallum, Michael to select the most appropriate patients to fit into a half day J. Jones, Mohammed Elsayed, Liz Tuck, John Wayman, Kate Carney (North Cumbria University Hospitals Trust); Somaiah Aroori, Kenneth operating list with a low risk of overrunning. Another use B. Hosie, Adam Kimble, David M. Bunting, Kenneth B. Hosie (Plym- could be to place patients with a long operative duration outh Hospitals NHS Trust); Adeshina S. Fawole, Mohammed Basheer, (and hence higher operative difficultly) on a specialist sur - Rajiv V. Dave, Janahan Sarveswaran, Elinor Jones, Chris Kendal (Mid geon’s operating list. Yorkshire NHS Trust); Michael P. Tilston, Martin Gough, Tom Wal- lace, Shailendra Singh, Justine Downing Katherine A. Mockford, Eyad Issa, Nayab Shah, Neal Chauhan (Northern Lincolnshire and Goole Acknowledgements We would like to acknowledge the help of NHS Foundation Trust); Timothy R. Wilson, Amir Forouzanfar, Jona- Amanda Kirkham, Statistician, Birmingham Clinical Trials Unit for than R. L. Wild, Emma Nofal, Catherine Bunnell, Khaliel Madbak help with managing the CholeS database, and Suwathini Ravichandran, (Doncaster and Bassetlaw Hospitals NHS Foundation Trust); Sudhin- Birmingham Health Informatics, for help with the UHB database. dra T. V. Rao, Laurence Devoto, Najaf Siddiqi, Zechan Khawaja (Dor- CholeS Study Management Team set County Hospital NHS Foundation Trust); James C. Hewes, Laura Ravinder S. Vohra, Consultant Surgeon, Nottingham Oesophago- Gould, Alice Chambers, Daniel Urriza Rodriguez (North Bristol NHS Gastric Unit, Nottingham University Hospitals NHS Foundation Trust, Trust); Gourab Sen, Stuart Robinson, Kate Carney, Francis Bartlett Hucknall Road, Nottingham, UK; (Freeman Hospital); David M. Rae, Thomas E. J. Stevenson, Kas Sar- Amanda J. Kirkham, Biostatistician; Cancer Research UK Clinical vananthan (Frimley Park Hospital NHS Trust); Simon J. Dwerryhouse, Trials Unit, The University of Birmingham, Birmingham, UK; 1 3 Surgical Endoscopy (2018) 32:3149–3157 3155 Simon M. Higgs, Oliver J. Old, Thomas J. Hardy, Reena Shah Steve T. Soulat Raza (Burton Hospitals NHS Foundation Trust); Manzarul Hornby, Ken Keogh, Lucinda Frank (Gloucestershire Hospitals NHS Haque, Imran Alam, Rabiya Aseem, Shakira Patel, Mehek Asad (Royal Trust); Musallam Al-Akash, Emma A. Upchurch (Great Western Hos- Albert Edward Infirmary, Wigan Wrightington and Leigh NHS Trust); pitals NHS Foundation Trust); Richard J. Frame, Michael Hughes, Michael I. Booth, William R. Ball, Christopher P. J. Wood, Ana C. Clare Jelley (Harrogate and District NHS Foundation Trust); Simon Pinho-Gomes (Royal Berkshire NHS Foundation Trust); Ambareen Weaver, Sudipta Roy, Toritseju O. Sillo, Giorgios Galanopoulos (Wye Kausar, Moh’d Rami Obeidallah (East Lancashire Hospital Trust); Valley NHS Trust); Tamzin Cuming, Pedro Cunha, Salim Tayeh, Sar- Joseph Varghase, Joshil Lodhia, Donal Bradley, Carla Rengifo, David antos Kaptanis (Homerton University Hospital NHS Trust); Mohamed Lindsay (Royal Bolton Hospital NHS Foundation Trust); Sivakumar Heshaishi, Abdalla Eisawi, Michael Abayomi; Wee Sing Ngu, Katie Gopalswamy, Ian Finlay, Stacy Wardle, Naomi Bullen (Royal Cornwall Fleming, Dalvir S. Bajwa (Tees Hospitals NHS Foundation Trust); NHS Trust); Syed Yusuf Iftikhar, Altaf Awan, Javed Ahmed, Paul Vivek Chitre, Kamal Aryal, Paul Ferris (Paget University Hospitals Leeder (Royal Derby NHS Foundation Trust); Guiseppe Fusai, Giles NHS Foundation Trust); Michael Silva, Simon Lammy Sarah Bond-Smith, Alicja Psica, Yogesh Puri (Royal Free, London); David Mohamed, Amir Khawaja, Adnan Hussain, Mudassar A. Ghazanfar, Hou, Fergus Noble, Karoly Szentpali, Jack Broadhurst (Hampshire Maria Irene Bellini (Oxford University NHS Trust); Hamdi Ebdewi, Hospital NHS Foundation Trust); Ravindra Date, Martin R. Hossack, Mohamed Elshaer, Gianpiero Gravante, Benjamin Drake (Kettering Yan Li Goh, Paul Turner, Vinutha Shetty (Lancashire Teaching Hos- General Hospital NHS Foundation Trust); Arikoge Ogedegbe, pitalsNHS Foundation Trust); Manel Riera, Christina A. W. Macano, Dipankar Mukherjee, Chanpreet Arhi, Lola Giwa Nusrat Iqbal (Bark- Anisha Sukha (Royal Shrewsbury Hospital); Shaun R. Preston, Jennifer ing, Havering and Redbridge University Hospitals NHS Trust); Nicho- R. Hoban, Daniel J. Puntis, Sophie V. Williams (Royal Surrey County las F. Watson, Smeer Kumar Aggarwal, Philippa Orchard, Eduardo Hospital NHS Foundation Trust); Richard Krysztopik, James Kynas- Villatoro (Kings Mill Hospital); Peter D. Willson, Kam Wa Jessica ton, Jeremy Batt, Matthew Doe (Royal United Hospital Bath NHS Mok, Thomas Woodman, Jean Deguara (Kingston Hospital NHS Foun- Trust); Andrzej Goscimski, Gareth H. Jones, Stella R. Smith, Claire dation Trust); Giuseppe Garcea, Benoy I. Babu, A. R. Dennison, Deep Hall (Salford Royal NHS Foundation Trust); Nick Carty, Jamil Ahmed, Malde, David Lloyd, Steve Satheesan, Omer Al-Taan, Alexander Sofoklis Panteleimonitis (Salisbury Hospital Foundation Trust); Rohan Boddy (University Hospitals of Leicester NHS Trust); John P. Slavin, T. Gunasekera, Andrea R. G. Sheel, Hannah Lennon, Caroline Hindley Robert P. Jones, Laura Ballance, Stratos Gerakopoulos (Leighton Hos- (Southport and Ormskirk Hospital NHS Trust); Marcus Reddy, Ross pital, Mid Cheshire Hospitals NHS Foundation Trust); Periyathambi Kenny, Natalie Elkheir, Emma R. McGlone (St George’s Healthcare Jambulingam, Sami Mansour, Naomi Sakai, Vikas Acharya (Luton & NHS Trust); Rajasundaram Rajaganeshan, Kate Hancorn, Anita Har- Dunstable University Hospital NHS Foundation Trust); Mohammed greaves (St Helens and Knowsley Teaching Hospitals NHS Trust); Raj M. Sadat, Lawen Karim, David Larkin, Khalid Amin (Macclesfield Prasad, David A. Longbotham, Dhakshinamoorthy Vijayanand, Imeshi District General Hospital); Amarah Khan, Jennifer Law, Saurabh Jam- Wijetunga (Leeds Teaching Hospitals); Paul Ziprin, Christopher R. dar, Stella R. Smith, Keerthika Sampat, Kathryn M. O’shea (Central Nicolay, Geoffrey Yeldham, Edward Read (Imperial College Health- Manchester NHS Foundation Trust); Mangta Manu, Fotini M. Asprou, care NHS Trust); James A. Gossage, Rachel C. Rolph, Husam Ebied, Nabeela S. Malik, Jessica Chang, Marianne Johnstone (Royal Wolver- Manraj Phull (St Thomas’ Hospital, London); Mohammad A. Khan, hampton Hospitals NHS Trust); Michael Lewis, Geoffrey P. Roberts, Matthew Popplewell, Dimitrios Kyriakidis, Anwar Hussain (Mid Staf- Babu Karavadra, Evangelos Photi (Norfolk and Norwich University fordshire NHS Foundation Trust); Natasha Henley, Jessica R. Packer, Hospitals NHS Foundation Trust); James Hewes, Laura Gould, Alice Laura Derbyshire, Jonathan Porter (Stockport NHS Foundation Trust); Chambers, Dan Rodriguez (North Bristol NHS Trust); Derek A. Shaun Appleton, Marwan Farouk, Melvinder Basra (Bucks Healthcare O’Reilly, Anthony J. Rate, Hema Sekhar, Lucy T. Henderson, Benja- NHS Trust); Neil A. Jennings, Shahda Ali, Venkatesh Kanakala (City min Z. Starmer, Peter O. Coe, Sotonye Tolofari, Jenifer Barrie (Pennine Hospitals Sunderland NHS Foundation Trust); Haythem Ali, Risha Acute NHS Trust); Gareth Bashir, Jake Sloane, Suroosh Madanipour, Lane, Richard Dickson-Lowe, Prizzi Zarsadias (Tunbridge Wells and Constantine Halkias, Alexander E. J. Trevatt (North Middlesex Trust); Maidstone NHS Trust); Darius Mirza, Sonia Puig, Khalid Al Amari, David W. Borowski, Jane Hornsby, Michael J. Courtney, Suvi Virupak- Deepak Vijayan, Robert Sutcliffe, Ravi Marudanayagam (University sha (North Tees and Hartlepool NHS Foundation Trust); Keith Sey- Hospital Birmingham NHS Foundation Trust); Zayed Hamady, mour, Sarah Robinson, Helen Hawkins, Sadiq Bawa, Paul V. Gallagher, Abheesh R. Prasad, Abhilasha Patel (University Hospital Coventry and Alistair Reid, Peter Wood (Northumbria Healthcare NHS Foundation Warwickshire NHS Trust); Damien Durkin, Parminder Kaur, Laura Trust); J. G. Finch, J. Guy Finch, J. Parmar, E. Stirland (Northampton Bowen (University Hospital of North Staffordshire NHS Trust); James General Hospital NHS Trust); James Gardner-Thorpe, Ahmed Al- P. Byrne, Katherine L. Pearson, Theo G. Delisle, James Davies (Uni- Muhktar, Mark Peterson, Ali Majeed (Sheffield Teaching Hospitals versity Hospital Southampton NHS Foundation Trust); Mark A. Tom- NHS Foundation Trust); Farrukh M. Bajwa, Jack Martin, Alfred Choy, linson, Michelle A. Johnpulle, Corinna Slawinski (University Hospitals Andrew Tsang (Peterborough City Hospital); Naresh Pore, David R. of Morecambe Bay); Andrew Macdonald, James Nicholson, Katy Andrew, Waleed Al-Khyatt, Christopher Taylor, Santosh Bhandari, Newton, James Mbuvi (University Hospital South Manchester NHS Adam Chambers, Dhivya Subramanium (United Lincolnshire Hospitals Foundation Trust); Ansar Farooq, Bhavani Sidhartha Mothe, Zakhi NHS Trust); Simon K. C. Toh, Nicholas C. Carter, Sophie Tate, Zafrani, Daniel Brett (Warrington and Halton Hospitals NHS Trust); Belinda Pearce, Denise Wainwright, Stuart J. Mercer, Benjamin Knight James Francombe, Philip Spreadborough, James Barnes, Melanie (Portsmouth Hospitals NHS Trust); Vardhini Vijay, Swethan Alagarat- Cheung (South Warwickshire NHS Foundation Trust); Ahmed Z. Al- nam, Sidhartha Sinha, Shahab Khan (The Princess Alexandra Hospital Bahrani, Giuseppe Preziosi, Tomas Urbonas (Watford General Hospi- NHS Trust); Shamsi S. El-Hasani, Abdulzahra A. Hussain (Kings Col- tal); Justin Alberts, Mekhlola Mallik, Krashna Patel, Ashvina Segaran, lege Hospital NHS Foundation Trust); Vish Bhattacharya, Nisheeth Triantafyllos Doulias (West Suffolk NHS Trust); Pratik A. Sufi, Caro- Kansal, Tani Fasih, Claire Jackson (Gateshead Health NHS Foundation line Yao, Sarah Pollock (Whittington NHS Trust); Antonio Manzelli, Trust); Midhat N. Siddiqui, Imran A. Chishti, Imogen J. Fordham, Saj Wajed, Michail Kourkulos, Roberto Pezzuto (Wonford Hospital); Zohaib Siddiqui (Lewisham and Greenwich NHS Trust); Harald Baus- Martin Wadley, Emma Hamilton, Shameen Jaunoo, Robert Padwick bacher, Ileana Geogloma, Kabita Gurung (Queen Elizabeth Hospital (Worcestershire Acute Hospitals NHS Trust); Mazin Sayegh, Richard NHS Trust); George Tsavellas, Pradeep Basynat, Ashish Kiran C. Newton, Madhusoodhana Hebbar, Sameh F. Farag, (Western Sussex Shrestha, Sanjoy Basu, Alok Chhabra Mohan Harilingam, Mohamed Hospitals NHS Foundation Trust); John Spearman, Mohammed F. Hamdan, Conrad D’Costa, Christine Blane; (Yeovil District Hospital Rabie, Mansoor Akhtar (East Kent Hospitals University NHS Founda- NHS Trust); Mathew Giles, Mark B. Peter, Natalie A. Hirst, Tanvir tion Trust); Pradeep Kumar, Sadaf F. Jafferbhoy, Najam Hussain, 1 3 3156 Surgical Endoscopy (2018) 32:3149–3157 Hossain, Arslan Pannu Yesar El-Dhuwaib, Tamsin E. M. Morrison, Shahin, Aymon, Ali Alison Luther, James A. Nicholson, Ilayaraja Greg W. Taylor (York Teaching Hospital NHS Foundation Trust). Rajendran, Matthew Boal, Judith Ritchie. Northern Ireland—Ronald L. E. Thompson, Ken McCune, Paula Loughlin, Roger Lawther (Altnagelvin Area Hospital); Colman K. Compliance with ethical standards Byrnes, Duncan J. Simpson, Abi Mawhinney, Conor Warren (Antrim Area Hospital); Damian McKay, Colin McIlmunn, Serena Martin, Mat- Disclosure Miss Reshma Bharamgoudar, Mr Aniket Sonsale, Mr James thew MacArtney (Daisy Hill Hospital); Tom Diamond, Phil Davey, Hodson and Mr Ewen Griffiths have no conflicts of interest or financial Claire Jones, Joshua M. Clements, Ruairi Digney, Wei Ming Chan, Ste- ties to disclose. phen McCain, Sadaf Gull, Adam Janeczko, Emmet Dorrian, Andrew Harris, Suzanne Dawson, Dorothy Johnston, Barry McAree, (Belfast City Hospital, Mater Infirmorum Hospital Belfast and Royal Victoria Open Access This article is distributed under the terms of the Creative Hospital); Essam Ghareeb, George Thomas, Martin Connelly, Ste- Commons Attribution 4.0 International License (http://creativecom- phen McKenzie, Krzysztos Cieplucha (South West Acute Hospital); mons.org/licenses/by/4.0/), which permits unrestricted use, distribu- Gary Spence, William Campbell, Gareth Hooks, Neil Bradley (Ulster tion, and reproduction in any medium, provided you give appropriate Hospital). credit to the original author(s) and the source, provide a link to the Republic of Ireland—Arnold D. K. Hill, John T. Cassidy, Michael Creative Commons license, and indicate if changes were made. Boland (Beaumont Hospital, Dublin); Paul Burke, Deirdre M. Nally (University Hospital Limerick); Arnold D. K. Hill, Elmoataz Khogali, Wael Shabo, Edrin Iskandar (Louth County Hospital and Our Lady of Lourdes Hospital); Gerry P. McEntee, Maeve A. O’Neill, Colin Pei- rce, Emma M. Lyons (Mater Hospital, Dublin); Adrian W. O’Sullivan, References Rohan Thakkar, Paul Carroll, Ivan Ivanovski (Mercy University Hospi- tal); Paul Balfe, Matthew Lee (St Luke’s General Hospital Kilkenny); 1. NHS Digital (2017) Hospital admitted patient care activity, Des C. Winter, Michael E. Kelly, Emir Hoti, Donal Maguire; Priya- pp 2015–2016 darssini Karunakaran, Justin G. Geoghegan, Frank McDermott, Sean T. 2. Subhas G, Gupta A, Bhullar J, Dubay L, Ferguson L, Goriel Y, Martin (St Vincent’s University and Private Hospitals, Dublin); Keith Jacobs MJ, Kolachalam RB, Silapaswan S, Mittal VK (2011) S. Cross, Fiachra Cooke, Saquib Zeeshan, James O. Murphy (Waterford Prolonged (longer than 3 hours) laparoscopic cholecystectomy: Regional Hospital); Ken Mealy, Helen M. 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University Hospitals Birmingham NHS Foundation 22. Goh YL, Toumi Z, Mok KW, Date RS (2015) Variation in conver- Trust, Birmingham sion rates of laparoscopic cholecystectomy in different set-ups can 17. American Society of Anaesthesiologists (2017) ASA physical sta- be explained on the basis of C-reactive protein (CRP) values at tus classification system. American Society of Anaesthesiologists, index admission. Int J Surg 15:38–39 Schaumburg 23. Sankar A, Johnson SR, Beattie WS, Tait G, Wijeysundera 18. Archer T, Macario A (2006) The drive for operating room effi- DN (2014) Reliability of the American Society of Anesthesi- ciency will increase quality of patient care. Curr Opin Anaesthe- ologists physical status scale in clinical practice. Br J Anaesth siol 19:171–176 113:424–432 1 3 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Surgical Endoscopy Springer Journals

The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

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Springer Journals
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Copyright © 2018 by The Author(s)
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Medicine & Public Health; Surgery; Gynecology; Gastroenterology; Hepatology; Proctology; Abdominal Surgery
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0930-2794
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1432-2218
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10.1007/s00464-018-6030-6
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Abstract

Background The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utili- sation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p < 0.001), with the proportions of operations lasting > 90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care. Keywords Laparoscopic cholecystectomy · Patient factors · Operative duration · Scoring tool · Prediction · Theatre utilisation There are 70,000 cholecystectomies performed in the UK each year, making it one of the most common general sur- gical operations [1]. The average operative duration for * Ewen Griffiths this laparoscopic procedure is usually < 1 h [2]. With the ewen.griffiths@uhb.nhs.uk average hourly cost for an operating theatre being £1200, efforts to utilise every minute of allocated theatre time is College of Medical & Dental Sciences, University of Birmingham, Birmingham, UK vital [3]. This is especially so in a resource constrained National Health Service (NHS) working environment that Institute of Translational Medicine, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK is required to save £20 bn by 2020 to remain sustainable for the future [4]. Poor planning can lead to cancellations, Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, which are expensive for the Trust and, more importantly, Birmingham, UK distressing for patients. One particular study found that 63% Department of Upper Gastrointestinal Surgery, University of on-the-day cancellations were due to a lack of theatre time Hospitals Birmingham NHS Foundation Trust, Birmingham, [5], with another study demonstrating that approximately UK Vol.:(0123456789) 1 3 3150 Surgical Endoscopy (2018) 32:3149–3157 30% of lists are under-run, leaving the operating theatre idle (N = 5), as these were thought to be unrealistic. This left a [6]. Careful planning and scheduling is therefore paramount total of 7227 patients for analysis. to increase operating theatre efficiency and, in doing so, it is estimated that NHS trusts can make efficiency savings Validation dataset of approximately £4 m per year [3]. In a time where ris- ing demographic pressures are demanding ever increasing The validation dataset was retrospectively collected from the spending on healthcare, it is vital we optimise the use of our University Hospitals Birmingham NHS Foundation Trust existing resources. (UHB)—a large tertiary hospital with 1213 inpatient beds Previous research in other surgical areas has assessed a and 32 operating theatres [16]. Data were collected for all variety of patient factors and their impact on operative dura- elective laparoscopic cholecystectomies carried out between tion [7–11], but studies in laparoscopic cholecystectomy are 2010 and 2016, excluding emergencies, as well as those few and a predictive scoring tool is yet to be developed. Tra- having combined procedures. This left a total of N = 2405 ditionally, surgeons have estimated their operative durations, patients for analysis. Data for surgical duration and pre- but research has demonstrated that these estimates are often operative factors were gathered from a variety of electronic inaccurate [6]. Many hospitals have now moved to electronic hospital systems, including the Lorenzo patient information systems and central schedulers with the aim of reducing system, Galaxy operating theatre system and PICS (Prescrib- costs. However, such systems require significant learning ing Information and Communication system). ASA grades time to adapt to organisational needs [12]. Historical proce- were calculated using comorbidities derived from the infor- dure and surgeon data have been used to estimate operative matics database, and were based on the definitions provided duration. However, this is known to be of low accuracy, as it by the American Society of Anaesthesiologists [17]. fails to account for pre-operative patient factors [12]. We aimed to create a clinically useful scoring tool to pre- Statistical methods dict the operative duration of laparoscopic cholecystectomy using pre-operative patient factors and to externally validate Initially, the operative duration was dichotomised into its reliability using a separate dataset. groups of ≤ 90 vs. > 90  min. Univariable analyses were then performed, comparing the rates of operative durations > 90 min across a range of factors. Comparisons across cat- egorical factors were made using Fisher’s exact tests, whilst Methods Mann–Whitney tests were used to compare ordinal factors between the operative duration groups. Two datasets were used in this study, to allow for a risk score A multivariable analysis was then performed to identify to be produced and externally validated: independent predictors of operative duration. A binary logis- tic regression model was produced, with a forwards stepwise CholeS dataset approach used to select variables for inclusion. The resulting model was then converted to a risk score, by rounding the The CholeS study was a multicentre, prospective popula- beta coefficient (log-odds) of each factor to the nearest 0.5, tion-based cohort study that assessed variations in patient after multiplying by a constant to minimise the impact of factors with outcomes of cholecystectomy [13, 14]. The rounding errors. Where this resulted in negative values, the protocol for this study has been published previously [15]. reference category was changed, such that all values in the Data were collected from 8820 patients who underwent a score were positive. The predictive accuracy of the model laparoscopic cholecystectomy at 166 hospitals in the UK was then assessed using ROC curves. The model was also between March to April 2014, and was found to be 99.2% applied to a second cohort of patients for external validation. accurate by independent data validation. Pre-operative vari- All analyses were performed using IBM SPSS 22 (IBM ables included patient demographics, indications for surgery, Corp. Armonk, NY), with p < 0.05 deemed to be indicative admission type, ASA grade, ultrasound findings and pre- of statistical significance throughout. operative ERCP. Surgical duration was calculated from the time (minutes) of skin incision to end of skin closure. For this study, all patients undergoing emergency chol- Results ecystectomy were excluded (N = 1420), as these are associ- ated with long procedure times and elective theatre utilisa- Demographics tion was the focus of this study. In addition, those where the operative duration was not recorded (N = 168) were After exclusions, data were available for 7227 surgeries in excluded, as were those with an operative duration < 10 min the derivation (CholeS) cohort. The patients had a mean 1 3 Surgical Endoscopy (2018) 32:3149–3157 3151 Table 1 Univariable analysis of associations between operative dura- Table 1 (continued) tion and both demographic and pre-operative factors N Operative p Value dura- N Operative p Value tion > 90 min dura- tion > 90 min  >2 170 57 (33.5%) Age (years) < 0.001** ASA < 0.001*  < 30 854 90 (10.5%)  1 2803 352 (12.6%)  30–39 1035 128 (12.4%)  2 3687 722 (19.6%)  40–49 1397 237 (17.0%)  >2 690 199 (28.8%)  50–59 1534 297 (19.4%) Data reported as N (%), with p values from Fisher’s exact tests, unless  60–69 1381 282 (20.4%) stated otherwise  70+ 1023 245 (23.9%) *p Value from a Mann–Whitney test, to account for the ordinal nature Gender < 0.001 of the factor  Female 5406 852 (15.8%) **p Value from a Mann–Whitney test, using the exact age. Bold p  Male 1821 427 (23.4%) values are significant at p < 0.05 Indication for surgery < 0.001  Acalculous/cholecystitis 1739 483 (27.8%) age of 51 years (SD = 16), and the majority were female  CBD stone 479 145 (30.3%) (74.8%). The median operative duration was 60 min, with  Colic/dyskinesia/polyp 4435 541 (12.2%) an interquartile range (IQR) of 45–85 min. Operations lasted  Pancreatitis 570 109 (19.1%) for > 90 min in 17.7% (N = 1279) of the cohort. BMI < 0.001*  <25 1475 219 (14.8%) Risk score derivation  25–30 2465 424 (17.2%)  31–35 1689 305 (18.1%) Associations between the operative duration and a range  >35 1324 279 (21.1%) of demographic and pre-operative factors are reported in CBD diameter < 0.001 Table 1. All of the factors considered were found to be sig-  Normal 6013 936 (15.6%) nificantly associated with longer operative durations. For  Dilated 1063 310 (29.2%) this reason, a multivariable analysis was performed, in order Gallbladder wall < 0.001 to identify which factors were independently associated  Normal 5017 708 (14.1%) with operative duration (Table 2). This analysis found the  Thick walled 2053 530 (25.8%) likelihood of an operation taking > 90 min to increase sig- Pre-operative MRCP < 0.001 nificantly with BMI (p < 0.001), ASA grade (p < 0.001), and  No 5325 857 (16.1%) the number of previous surgical admissions that the patient  Yes 1819 419 (23.0%) had (p = 0.005). In addition, the indication on admission Pre-operative CT < 0.001 significantly influenced operative duration (p < 0.001), with  No 6158 1006 (16.3%) patients admitted with acalculous and cholecystitis being  Yes 978 271 (27.7%) the most likely to have operations lasting > 90 min. Patients Pre-operative ERCP < 0.001 with a thickened gallbladder, a dilated CBD diameter, or  No 6349 1049 (16.5%) who had received a pre-operative CT or planned intra-oper-  Yes 783 227 (29.0%) ative cholangiogram were significantly more likely to take Grade of senior surgeon 0.005* > 90 min (all p < 0.001). In addition, patients of male gender  <ST5 308 42 (13.6%) (p = 0.002) and aged 40+ (p = 0.004) were also at signifi-  >ST6 1165 183 (15.7%) cantly higher risk of requiring a longer operative duration.  Consultant 5748 1052 (18.3%) These 10 factors were then combined to form a risk score Planned intra-op cholangiogram < 0.001 (Table  3). This score has a potential range from 0 to 20,  No 6519 1070 (16.4%) although the observed range in the cohort was 0.5–17.5  Yes 655 203 (31.0%) (median = 5). A ROC curve analysis returned an area under Number of previous surgical < 0.001* admissions the curve (AUROC) of 0.696 (SE = 0.009, p < 0.001) for the  0 4006 535 (13.4%) prediction of operations lasting > 90 min.  1 2424 546 (22.5%)  2 486 118 (24.3%) 1 3 3152 Surgical Endoscopy (2018) 32:3149–3157 Table 2 Multivariable analysis a Beta Odds ratio (95% CI) p Value of predictors of > 90 min operations Age (years) 0.004  <30 0 1 –  30–39 0.058 1.06 (0.78–1.45) 0.714  40–49 0.430 1.54 (1.16–2.05) 0.003  50–59 0.438 1.55 (1.17–2.06) 0.002  60–69 0.366 1.44 (1.07–1.93) 0.015  70+ 0.380 1.46 (1.07–2.00) 0.017 Gender (male) 0.241 1.27 (1.09–1.48) 0.002 Indication < 0.001  Acalculous/cholecystitis 0 1 –  CBD stone − 0.154 0.86 (0.66–1.12) 0.258  Colic/dyskinesia/polyp − 0.527 0.59 (0.49–0.71) < 0.001  Pancreatitis − 0.627 0.53 (0.41–0.70) < 0.001 BMI < 0.001  <25 0 1 –  25–30 0.208 1.23 (1.01–1.49) 0.035  31–35 0.291 1.34 (1.09–1.65) 0.006  >35 0.532 1.70 (1.36–2.13) < 0.001 CBD diameter (dilated) 0.535 1.71 (1.42–2.05) < 0.001 Gallbladder wall (thick) 0.371 1.45 (1.24–1.70) < 0.001 Pre-operative CT 0.320 1.38 (1.15–1.65) < 0.001 Planned intra-op cholangiogram 0.706 2.03 (1.66–2.47) < 0.001 Number of previous surgical admissions 0.005  0 0 1 –  1 0.202 1.22 (1.03–1.45) 0.020  2 0.227 1.25 (0.96–1.64) 0.095  >2 0.630 1.88 (1.29–2.74) 0.001 ASA < 0.001  1 0 1 –  2 0.225 1.25 (1.06–1.47) 0.007  >2 0.630 1.88 (1.48–2.39) < 0.001 Results are from a multivariable binary logistic regression model with a forward stepwise approach to vari- able selection. All factors from Table 1 were considered for inclusion in the model. Bold p values are sig- nificant at p < 0.05 The beta coefficients (i.e. log-odds) from the model Validation Discussion The risk score was then applied to a cohort of N = 2405 Our study has created a scoring tool that uses pre-operative patients from UHB for external validation. This cohort had patient factors to predict the probability that a laparoscopic a similar operative duration to the derivation cohort, with a cholecystectomy will take > 90 min. This scoring tool has median of 66 min (IQR: 52–85), and with 20.0% (N = 481) also been successfully externally validated against a sepa- of operations taking > 90 min. The median risk score was rate dataset and has demonstrated predictive accuracy. The found to be 4.5, with a range from 0 to 14.5. The score as results showed that, for low-scoring individuals vs. high- a whole had a similar degree of predictive accuracy to that scoring individuals, the proportion of operations taking observed in the derivation cohort, with an AUROC of 0.708 > 90 min increases significantly from 5.8 to 41.4%. (SE = 0.013, p < 0.001) (Fig. 1). We hope this scoring tool could enable better plan- ning and utilisation of elective theatre lists. A better 1 3 Surgical Endoscopy (2018) 32:3149–3157 3153 Table 3 Risk score Points Age (years)  <40 0  40+ 1.5 Gender (male)  Female 0  Male 1 Indication  Pancreatitis 0  Colic/dyskinesia/polyp 0.5  CBD stone 2  Acalculous/cholecystitis 2.5 BMI Fig. 1 Demonstrates the relationship between the risk score and the  <25 0 proportion of operations taking > 90 min in the validation cohort. Of  25–35 1 the 470 patients with risk scores of 0–3, only 5.1% (N = 24) of opera-  >35 2 tions took > 90 min, increasing to 41.8% (109/261) in those with risk CBD diameter scores > 8  Normal 0  Dilated 2 Gallbladder wall possible, given that laparoscopic cholecystectomies are one  Normal 0 of the most commonly performed operations in the NHS [1].  Thick 1.5 Thiels et al. [12] assessed the surgical duration of 1801 Pre-operative CT elective laparoscopic cholecystectomies from 2007 to 2013  No 0 and found female sex, BMI, ASA grade and pre-operative  Yes 1.5 laboratory results to be predictive factors in influencing Planned intra-op cholangiogram operative duration. They used a large group of patients  No 0 from the NSQIP (American College of Surgeons National  Yes 3 Surgical Quality Improvement Program) to validate their Number of previous surgical admissions findings [12]. Zdichavsky et al. [20] performed a retrospec-  0 0 tive analysis of 677 consecutive patients undergoing lapa-  1–2 1 roscopic cholecystectomies from 2004 to 2007 (excluding  >2 2.5 conversions, intra-operative cholangiogram and concurrent ASA liver cirrhosis) and found male sex, obesity, acute cholecys-  1 0 titis and previous abdominal surgery to be independently  2 1 predictive of duration. In a small study of only 138 chol-  >2 2.5 ecystectomies, junior residents took significantly longer to complete a cholecystectomy than their senior counterparts Based on the multivariable analysis in Table 2. The number of points (p < 0.05) [21]. for each factor was calculated by rounding the beta coefficient to the nearest 0.5, after multiplying by 4 to minimise rounding errors. Cat- In our study, factors found to be independently predictive egories for a factor that had the same number of points (e.g. age < 30 of operative duration were patient age, gender, ASA grade, and 30–39) were combined to simplify the table operative indication, BMI, CBD diameter, gallbladder wall thickness, pre-operative CT scan, planned intra-operative understanding of patient factors that result in increased cholangiogram and the number of previous surgical admis- operative duration and how this affects surgeon workload sions. These factors are broadly similar to previous work by can help to optimise theatre scheduling and result in fewer other researchers [12, 20, 21]. Our study expands on their cancellations. With theatres being one of the most expensive work and has developed a clinically useful scoring tool. To resources to run [18], even small improvements in theatre our knowledge, this is the first study to use patient factors to utilisation have the potential to impact costs greatly, and create a validated scoring tool to predict operative duration with many trusts under pressure to tackle unsustainable for elective laparoscopic cholecystectomies. deficits [ 19], it is possible that utilising this scoring tool Our study uses high-quality, validated, prospective may be helpful in addressing this issue. This is particularly data that were collected as part of the CholeS study. The 1 3 3154 Surgical Endoscopy (2018) 32:3149–3157 Sandro Pasquali, Surgical trainee, Surgical Oncology Unit, Veneto substantial cohort of 7227 patients is considerably larger Institute of Oncology IOV-IRCCS, Padova, Italy; than those used by past researchers, which altogether gives Paul Marriott, Surgical trainee, West Midlands Research Collabora- greater assurance as to the reliability of the derived scoring tive, Academic Department of Surgery, The University of Birmingham, tool. In addition, we have external validated our scoring tool Birmingham, UK; Marianne Johnstone, Surgical trainee, West Midlands Research and its utility to successfully predict operative duration. Our Collaborative, Academic Department of Surgery, The University of scoring tool can be used pre-operatively and was developed Birmingham, Birmingham, UK; in a dataset which included patients who underwent conver- Philip Spreadborough, Surgical trainee, West Midlands Research sion to open surgery and cholangiography and is therefore Collaborative, Academic Department of Surgery, The University of Birmingham, Birmingham, UK more generalizable. There are however some limitations that Derek Alderson, Emeritus Professor of Surgery, Academic Depart- should be considered when analysing this study’s results. ment of Surgery, The University of Birmingham, Birmingham, UK; The CholeS study did not collect data on pre-operative Ewen A. Griffiths, Consultant Surgeon, Department of Upper Gas- blood results, such as white cell count or CRP, or whether trointestinal Surgery, University Hospitals Birmingham NHS Founda- tion Trust, Birmingham, UK the patient had previous Upper GI surgery, which may indi- CholeS Study Collaborators: cate difficult surgery [22]. We recognise that the validation England—Stephen Fenwick, Mohamed Elmasry, Quentin M. dataset was retrospectively collected from routine hospital Nunes, David Kennedy (Aintree University Hospital NHS Foundation data and therefore may have some inaccuracies. ASA grades Trust); Raja Basit Khan, Muhammad A. S. Khan (Airedale General Hospital); Conor J. Magee, Steven M. Jones, Denise Mason, Ciny P. were calculated retrospectively based on information from Parappally (Wirral University Teaching Hospital); Pawan Mathur, the patients’ clinical records. However, even when ASA is Michael Saunders, Sara Jamel, Samer Ul Haque, Sara Zafar (Barnet calculated by anaesthetists there is an element of bias and and Chase Farm Hospital); Muhammad Hanif Shiwani, Nehemiah variation [23]. Furthermore, this scoring tool has been devel- Samuel, Farooq Dar, Andrew Jackson (Barnsley District General Hos- pital); Bryony Lovett, Shiva Dindyal, Hannah Winter, Ted Fletcher, oped for elective cholecystectomy data and should not be Saquib Rahman (Basildon Univesity Hospital); Kevin Wheatley, Tom used to predict the duration of acute operations. Nieto, Soofiyah Ayaani (Sandwell and West Birmingham Hospitals NHS Trust); Haney Youssef, Rajwinder S. Nijjar, Helen Watkin, David Naumann, Sophie Emesih; Piyush B. Sarmah, Kathryn Lee, Nikita Joji, Joel Lambert (Heart of England Foundation NHS Trust); Jonathan Heath, Rebecca L. Teasdale, Chamindri Weerasinghe (Blackpool Conclusion Teaching Hospitals NHS Foundation Trust); Paul J. Needham, Hannah Welbourn, Luke Forster, David Finch (Bradford Teaching Hospitals We have created a scoring tool to predict operative dura- NHS Foundation Trust); Jane M. Blazeby, William Robb, Angus G. K. McNair, Alex Hrycaiczuk (University Hospitals Bristol NHS Trust); tions of elective laparoscopic cholecystectomies using pre- Alexandros Charalabopoulos, Sritharan Kadirkamanathan, Cheuk- operative patient factors. Whilst previous research may Bong Tang, Naga V. G. Jayanthi, Nigel Noor (Broomfield Hospital); have examined the significance of individual factors, there Brian Dobbins, Andrew J. Cockbain, April Nilsen-Nunn, Jonathan de remained a lack of a formal scoring tool. Using the 7227 Siqueira (Calderdale and Huddersfield NHS Trust); Mike Pellen, Jona- than B. Cowley, Wei-Min Ho, Victor Miu (Hull and East Yorkshire patient CholeS dataset to derive the scoring system, and NHS Trust); Timothy J. White, Kathryn A. Hodgkins, Alison Kinghorn a UHB database of 2405 patients to subsequently validate (Chesterfield Royal Hospital NHS Foundation Trust); Matthew G. Tut- the tool, we have shown that it is possible to predict opera- ton, Yahya A. Al-Abed, Donald Menzies, Anwar Ahmad, Joanna Reed, tions that are likely to last greater than 90 min. This could Shabuddin Khan (Colchester Hospital University NHS Foundation Trust); David Monk, Louis J. Vitone, Ghulam Murtaza, Abraham Joel be useful for theatre schedulers to ensure theatre lists are (Countess of Chester NHS Foundation Trust); Stephen Brennan, David planned appropriately to optimise theatre utilisation and Shier, Catherine Zhang, Thusidaran Yoganathan (Croydon Health Ser- achieve cost savings. For example, the tool could be used vices NHS Trust); Steven J. Robinson, Iain J. D. McCallum, Michael to select the most appropriate patients to fit into a half day J. Jones, Mohammed Elsayed, Liz Tuck, John Wayman, Kate Carney (North Cumbria University Hospitals Trust); Somaiah Aroori, Kenneth operating list with a low risk of overrunning. Another use B. Hosie, Adam Kimble, David M. Bunting, Kenneth B. Hosie (Plym- could be to place patients with a long operative duration outh Hospitals NHS Trust); Adeshina S. Fawole, Mohammed Basheer, (and hence higher operative difficultly) on a specialist sur - Rajiv V. Dave, Janahan Sarveswaran, Elinor Jones, Chris Kendal (Mid geon’s operating list. Yorkshire NHS Trust); Michael P. Tilston, Martin Gough, Tom Wal- lace, Shailendra Singh, Justine Downing Katherine A. Mockford, Eyad Issa, Nayab Shah, Neal Chauhan (Northern Lincolnshire and Goole Acknowledgements We would like to acknowledge the help of NHS Foundation Trust); Timothy R. Wilson, Amir Forouzanfar, Jona- Amanda Kirkham, Statistician, Birmingham Clinical Trials Unit for than R. L. Wild, Emma Nofal, Catherine Bunnell, Khaliel Madbak help with managing the CholeS database, and Suwathini Ravichandran, (Doncaster and Bassetlaw Hospitals NHS Foundation Trust); Sudhin- Birmingham Health Informatics, for help with the UHB database. dra T. V. Rao, Laurence Devoto, Najaf Siddiqi, Zechan Khawaja (Dor- CholeS Study Management Team set County Hospital NHS Foundation Trust); James C. Hewes, Laura Ravinder S. Vohra, Consultant Surgeon, Nottingham Oesophago- Gould, Alice Chambers, Daniel Urriza Rodriguez (North Bristol NHS Gastric Unit, Nottingham University Hospitals NHS Foundation Trust, Trust); Gourab Sen, Stuart Robinson, Kate Carney, Francis Bartlett Hucknall Road, Nottingham, UK; (Freeman Hospital); David M. Rae, Thomas E. J. Stevenson, Kas Sar- Amanda J. Kirkham, Biostatistician; Cancer Research UK Clinical vananthan (Frimley Park Hospital NHS Trust); Simon J. Dwerryhouse, Trials Unit, The University of Birmingham, Birmingham, UK; 1 3 Surgical Endoscopy (2018) 32:3149–3157 3155 Simon M. Higgs, Oliver J. Old, Thomas J. Hardy, Reena Shah Steve T. Soulat Raza (Burton Hospitals NHS Foundation Trust); Manzarul Hornby, Ken Keogh, Lucinda Frank (Gloucestershire Hospitals NHS Haque, Imran Alam, Rabiya Aseem, Shakira Patel, Mehek Asad (Royal Trust); Musallam Al-Akash, Emma A. Upchurch (Great Western Hos- Albert Edward Infirmary, Wigan Wrightington and Leigh NHS Trust); pitals NHS Foundation Trust); Richard J. Frame, Michael Hughes, Michael I. Booth, William R. Ball, Christopher P. J. Wood, Ana C. Clare Jelley (Harrogate and District NHS Foundation Trust); Simon Pinho-Gomes (Royal Berkshire NHS Foundation Trust); Ambareen Weaver, Sudipta Roy, Toritseju O. Sillo, Giorgios Galanopoulos (Wye Kausar, Moh’d Rami Obeidallah (East Lancashire Hospital Trust); Valley NHS Trust); Tamzin Cuming, Pedro Cunha, Salim Tayeh, Sar- Joseph Varghase, Joshil Lodhia, Donal Bradley, Carla Rengifo, David antos Kaptanis (Homerton University Hospital NHS Trust); Mohamed Lindsay (Royal Bolton Hospital NHS Foundation Trust); Sivakumar Heshaishi, Abdalla Eisawi, Michael Abayomi; Wee Sing Ngu, Katie Gopalswamy, Ian Finlay, Stacy Wardle, Naomi Bullen (Royal Cornwall Fleming, Dalvir S. Bajwa (Tees Hospitals NHS Foundation Trust); NHS Trust); Syed Yusuf Iftikhar, Altaf Awan, Javed Ahmed, Paul Vivek Chitre, Kamal Aryal, Paul Ferris (Paget University Hospitals Leeder (Royal Derby NHS Foundation Trust); Guiseppe Fusai, Giles NHS Foundation Trust); Michael Silva, Simon Lammy Sarah Bond-Smith, Alicja Psica, Yogesh Puri (Royal Free, London); David Mohamed, Amir Khawaja, Adnan Hussain, Mudassar A. Ghazanfar, Hou, Fergus Noble, Karoly Szentpali, Jack Broadhurst (Hampshire Maria Irene Bellini (Oxford University NHS Trust); Hamdi Ebdewi, Hospital NHS Foundation Trust); Ravindra Date, Martin R. Hossack, Mohamed Elshaer, Gianpiero Gravante, Benjamin Drake (Kettering Yan Li Goh, Paul Turner, Vinutha Shetty (Lancashire Teaching Hos- General Hospital NHS Foundation Trust); Arikoge Ogedegbe, pitalsNHS Foundation Trust); Manel Riera, Christina A. W. Macano, Dipankar Mukherjee, Chanpreet Arhi, Lola Giwa Nusrat Iqbal (Bark- Anisha Sukha (Royal Shrewsbury Hospital); Shaun R. Preston, Jennifer ing, Havering and Redbridge University Hospitals NHS Trust); Nicho- R. Hoban, Daniel J. Puntis, Sophie V. Williams (Royal Surrey County las F. Watson, Smeer Kumar Aggarwal, Philippa Orchard, Eduardo Hospital NHS Foundation Trust); Richard Krysztopik, James Kynas- Villatoro (Kings Mill Hospital); Peter D. Willson, Kam Wa Jessica ton, Jeremy Batt, Matthew Doe (Royal United Hospital Bath NHS Mok, Thomas Woodman, Jean Deguara (Kingston Hospital NHS Foun- Trust); Andrzej Goscimski, Gareth H. Jones, Stella R. Smith, Claire dation Trust); Giuseppe Garcea, Benoy I. Babu, A. R. Dennison, Deep Hall (Salford Royal NHS Foundation Trust); Nick Carty, Jamil Ahmed, Malde, David Lloyd, Steve Satheesan, Omer Al-Taan, Alexander Sofoklis Panteleimonitis (Salisbury Hospital Foundation Trust); Rohan Boddy (University Hospitals of Leicester NHS Trust); John P. Slavin, T. Gunasekera, Andrea R. G. Sheel, Hannah Lennon, Caroline Hindley Robert P. Jones, Laura Ballance, Stratos Gerakopoulos (Leighton Hos- (Southport and Ormskirk Hospital NHS Trust); Marcus Reddy, Ross pital, Mid Cheshire Hospitals NHS Foundation Trust); Periyathambi Kenny, Natalie Elkheir, Emma R. McGlone (St George’s Healthcare Jambulingam, Sami Mansour, Naomi Sakai, Vikas Acharya (Luton & NHS Trust); Rajasundaram Rajaganeshan, Kate Hancorn, Anita Har- Dunstable University Hospital NHS Foundation Trust); Mohammed greaves (St Helens and Knowsley Teaching Hospitals NHS Trust); Raj M. Sadat, Lawen Karim, David Larkin, Khalid Amin (Macclesfield Prasad, David A. Longbotham, Dhakshinamoorthy Vijayanand, Imeshi District General Hospital); Amarah Khan, Jennifer Law, Saurabh Jam- Wijetunga (Leeds Teaching Hospitals); Paul Ziprin, Christopher R. dar, Stella R. Smith, Keerthika Sampat, Kathryn M. O’shea (Central Nicolay, Geoffrey Yeldham, Edward Read (Imperial College Health- Manchester NHS Foundation Trust); Mangta Manu, Fotini M. Asprou, care NHS Trust); James A. Gossage, Rachel C. Rolph, Husam Ebied, Nabeela S. Malik, Jessica Chang, Marianne Johnstone (Royal Wolver- Manraj Phull (St Thomas’ Hospital, London); Mohammad A. Khan, hampton Hospitals NHS Trust); Michael Lewis, Geoffrey P. Roberts, Matthew Popplewell, Dimitrios Kyriakidis, Anwar Hussain (Mid Staf- Babu Karavadra, Evangelos Photi (Norfolk and Norwich University fordshire NHS Foundation Trust); Natasha Henley, Jessica R. Packer, Hospitals NHS Foundation Trust); James Hewes, Laura Gould, Alice Laura Derbyshire, Jonathan Porter (Stockport NHS Foundation Trust); Chambers, Dan Rodriguez (North Bristol NHS Trust); Derek A. Shaun Appleton, Marwan Farouk, Melvinder Basra (Bucks Healthcare O’Reilly, Anthony J. Rate, Hema Sekhar, Lucy T. Henderson, Benja- NHS Trust); Neil A. Jennings, Shahda Ali, Venkatesh Kanakala (City min Z. Starmer, Peter O. Coe, Sotonye Tolofari, Jenifer Barrie (Pennine Hospitals Sunderland NHS Foundation Trust); Haythem Ali, Risha Acute NHS Trust); Gareth Bashir, Jake Sloane, Suroosh Madanipour, Lane, Richard Dickson-Lowe, Prizzi Zarsadias (Tunbridge Wells and Constantine Halkias, Alexander E. J. Trevatt (North Middlesex Trust); Maidstone NHS Trust); Darius Mirza, Sonia Puig, Khalid Al Amari, David W. Borowski, Jane Hornsby, Michael J. Courtney, Suvi Virupak- Deepak Vijayan, Robert Sutcliffe, Ravi Marudanayagam (University sha (North Tees and Hartlepool NHS Foundation Trust); Keith Sey- Hospital Birmingham NHS Foundation Trust); Zayed Hamady, mour, Sarah Robinson, Helen Hawkins, Sadiq Bawa, Paul V. Gallagher, Abheesh R. Prasad, Abhilasha Patel (University Hospital Coventry and Alistair Reid, Peter Wood (Northumbria Healthcare NHS Foundation Warwickshire NHS Trust); Damien Durkin, Parminder Kaur, Laura Trust); J. G. Finch, J. Guy Finch, J. Parmar, E. Stirland (Northampton Bowen (University Hospital of North Staffordshire NHS Trust); James General Hospital NHS Trust); James Gardner-Thorpe, Ahmed Al- P. Byrne, Katherine L. Pearson, Theo G. Delisle, James Davies (Uni- Muhktar, Mark Peterson, Ali Majeed (Sheffield Teaching Hospitals versity Hospital Southampton NHS Foundation Trust); Mark A. Tom- NHS Foundation Trust); Farrukh M. Bajwa, Jack Martin, Alfred Choy, linson, Michelle A. Johnpulle, Corinna Slawinski (University Hospitals Andrew Tsang (Peterborough City Hospital); Naresh Pore, David R. of Morecambe Bay); Andrew Macdonald, James Nicholson, Katy Andrew, Waleed Al-Khyatt, Christopher Taylor, Santosh Bhandari, Newton, James Mbuvi (University Hospital South Manchester NHS Adam Chambers, Dhivya Subramanium (United Lincolnshire Hospitals Foundation Trust); Ansar Farooq, Bhavani Sidhartha Mothe, Zakhi NHS Trust); Simon K. C. Toh, Nicholas C. Carter, Sophie Tate, Zafrani, Daniel Brett (Warrington and Halton Hospitals NHS Trust); Belinda Pearce, Denise Wainwright, Stuart J. Mercer, Benjamin Knight James Francombe, Philip Spreadborough, James Barnes, Melanie (Portsmouth Hospitals NHS Trust); Vardhini Vijay, Swethan Alagarat- Cheung (South Warwickshire NHS Foundation Trust); Ahmed Z. Al- nam, Sidhartha Sinha, Shahab Khan (The Princess Alexandra Hospital Bahrani, Giuseppe Preziosi, Tomas Urbonas (Watford General Hospi- NHS Trust); Shamsi S. El-Hasani, Abdulzahra A. Hussain (Kings Col- tal); Justin Alberts, Mekhlola Mallik, Krashna Patel, Ashvina Segaran, lege Hospital NHS Foundation Trust); Vish Bhattacharya, Nisheeth Triantafyllos Doulias (West Suffolk NHS Trust); Pratik A. Sufi, Caro- Kansal, Tani Fasih, Claire Jackson (Gateshead Health NHS Foundation line Yao, Sarah Pollock (Whittington NHS Trust); Antonio Manzelli, Trust); Midhat N. Siddiqui, Imran A. Chishti, Imogen J. Fordham, Saj Wajed, Michail Kourkulos, Roberto Pezzuto (Wonford Hospital); Zohaib Siddiqui (Lewisham and Greenwich NHS Trust); Harald Baus- Martin Wadley, Emma Hamilton, Shameen Jaunoo, Robert Padwick bacher, Ileana Geogloma, Kabita Gurung (Queen Elizabeth Hospital (Worcestershire Acute Hospitals NHS Trust); Mazin Sayegh, Richard NHS Trust); George Tsavellas, Pradeep Basynat, Ashish Kiran C. Newton, Madhusoodhana Hebbar, Sameh F. Farag, (Western Sussex Shrestha, Sanjoy Basu, Alok Chhabra Mohan Harilingam, Mohamed Hospitals NHS Foundation Trust); John Spearman, Mohammed F. Hamdan, Conrad D’Costa, Christine Blane; (Yeovil District Hospital Rabie, Mansoor Akhtar (East Kent Hospitals University NHS Founda- NHS Trust); Mathew Giles, Mark B. Peter, Natalie A. Hirst, Tanvir tion Trust); Pradeep Kumar, Sadaf F. Jafferbhoy, Najam Hussain, 1 3 3156 Surgical Endoscopy (2018) 32:3149–3157 Hossain, Arslan Pannu Yesar El-Dhuwaib, Tamsin E. M. Morrison, Shahin, Aymon, Ali Alison Luther, James A. Nicholson, Ilayaraja Greg W. Taylor (York Teaching Hospital NHS Foundation Trust). Rajendran, Matthew Boal, Judith Ritchie. Northern Ireland—Ronald L. E. Thompson, Ken McCune, Paula Loughlin, Roger Lawther (Altnagelvin Area Hospital); Colman K. Compliance with ethical standards Byrnes, Duncan J. Simpson, Abi Mawhinney, Conor Warren (Antrim Area Hospital); Damian McKay, Colin McIlmunn, Serena Martin, Mat- Disclosure Miss Reshma Bharamgoudar, Mr Aniket Sonsale, Mr James thew MacArtney (Daisy Hill Hospital); Tom Diamond, Phil Davey, Hodson and Mr Ewen Griffiths have no conflicts of interest or financial Claire Jones, Joshua M. Clements, Ruairi Digney, Wei Ming Chan, Ste- ties to disclose. phen McCain, Sadaf Gull, Adam Janeczko, Emmet Dorrian, Andrew Harris, Suzanne Dawson, Dorothy Johnston, Barry McAree, (Belfast City Hospital, Mater Infirmorum Hospital Belfast and Royal Victoria Open Access This article is distributed under the terms of the Creative Hospital); Essam Ghareeb, George Thomas, Martin Connelly, Ste- Commons Attribution 4.0 International License (http://creativecom- phen McKenzie, Krzysztos Cieplucha (South West Acute Hospital); mons.org/licenses/by/4.0/), which permits unrestricted use, distribu- Gary Spence, William Campbell, Gareth Hooks, Neil Bradley (Ulster tion, and reproduction in any medium, provided you give appropriate Hospital). credit to the original author(s) and the source, provide a link to the Republic of Ireland—Arnold D. K. Hill, John T. Cassidy, Michael Creative Commons license, and indicate if changes were made. Boland (Beaumont Hospital, Dublin); Paul Burke, Deirdre M. Nally (University Hospital Limerick); Arnold D. K. Hill, Elmoataz Khogali, Wael Shabo, Edrin Iskandar (Louth County Hospital and Our Lady of Lourdes Hospital); Gerry P. McEntee, Maeve A. O’Neill, Colin Pei- rce, Emma M. Lyons (Mater Hospital, Dublin); Adrian W. O’Sullivan, References Rohan Thakkar, Paul Carroll, Ivan Ivanovski (Mercy University Hospi- tal); Paul Balfe, Matthew Lee (St Luke’s General Hospital Kilkenny); 1. NHS Digital (2017) Hospital admitted patient care activity, Des C. Winter, Michael E. Kelly, Emir Hoti, Donal Maguire; Priya- pp 2015–2016 darssini Karunakaran, Justin G. Geoghegan, Frank McDermott, Sean T. 2. Subhas G, Gupta A, Bhullar J, Dubay L, Ferguson L, Goriel Y, Martin (St Vincent’s University and Private Hospitals, Dublin); Keith Jacobs MJ, Kolachalam RB, Silapaswan S, Mittal VK (2011) S. Cross, Fiachra Cooke, Saquib Zeeshan, James O. Murphy (Waterford Prolonged (longer than 3 hours) laparoscopic cholecystectomy: Regional Hospital); Ken Mealy, Helen M. 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Journal

Surgical EndoscopySpringer Journals

Published: Jan 16, 2018

References

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