TY - JOUR
AU - Özçakar,, Levent
AB - Abstract Objectives Peri- and postoperative pain frequently develops after joint replacement for severe knee osteoarthritis. A continuous nerve block is commonly used for pain relief, but the risks of infection and catheter dislodgement should be considered. The present mini-review aimed to brief the innervation and neural sonoanatomy of the knee joint and summarize the newest evidence of peripheral nerve stimulation (PNS) use in the management of knee pain. Methods We used a systematic approach to search for relevant articles. We used the combination of “peripheral nerve stimulation” and “knee pain” as the key words for the literature search using the electronic database without language or article type restriction. The search period was from the earliest record to August 2019. Results The present review identified six studies, four of which were related to PNS for management of postoperative knee pain and two of which probed neuropathic pain. Most of the studies were either case series or case reports. Based on our search result, PNS is likely to be a feasible and safe treatment for knee pain, but its effectiveness remains uncertain. Conclusions The present review reveals that PNS is feasible for the management of knee pain, especially in the postoperative period. The procedure is safe under ultrasound guidance used for proper placement of the electrodes near the target nerves. In the future, more prospective randomized controlled trials are needed to validate the effectiveness of PNS in acute and chronic knee pain. Knee Surgery, Pain, Genicular Nerve, Ultrasonography, Electrical Stimulation Introduction In recent years, knee pain has become more common because of population aging and the global obesity epidemic [1]. In a cross-sectional study on 504 old community residents, knee pain affected 46.2% of the overall population [2]. Cartilage degenerative pathology is the leading cause of chronic knee pain, and the conservative treatment includes medication, physical therapy, and rehabilitation exercises [3]. When the severity of osteoarthritis progresses, the patient may be referred for injections and eventually for joint replacement [4,5]. However, postoperative knee pain due to entrapment or irritation of the regional nerves is not uncommon [6]. Therefore, continuous nerve blocks have widely been used in the management of peri- and postoperative knee pain [7]. However, the long-term use of anesthetic nerve blocks has side effects, such as catheter displacement, infection, and potentiation of motor weakness and sensory deficits [8]. Peripheral nerve stimulation (PNS) is used to administer electric currents to the target nerve through a percutaneous lead connected to an external pulse generator [9]. Fluoroscopy has been used for guiding radiofrequency ablation, but it cannot exactly delineate peripheral nerves, which is paramount for PNS. High-resolution ultrasound (US) allows real-time direct visualization of peripheral nerves [10], although it has been criticized for being operator-dependent. US guidance eases the procedure of lead implantation by providing a direct view of the nerve and preventing collateral neurovascular damage. The most accepted mechanism underlying the effect of PNS on pain relief is the gate control theory, which suggests inhibition of nociceptive inputs from the small-diameter nerve fibers through activation of the large-diameter sensory nerve fibers [9]. The potential advantages of PNS (employing a helically coiled, fine-wired lead) include long duration of use, low risk of infection and lead migration, and less influence on sensory and motor functions of the stimulated zone [11]. As PNS has a novel clinical application in knee pain, few systematic reviews have been performed on it. The present mini-review aimed to brief the innervation and neural sonoanatomy of the knee joint and summarize the newest evidence of PNS use in the management of knee pain. Innervation of the Knee The anterior aspect of the knee joint is innervated by the saphenous, recurrent peroneal, common peroneal, superior medial genicular, inferior medial genicular, superior lateral genicular, and inferior lateral genicular nerves and nerves to the vastus medialis, lateralis, and intermedius muscles [12]. The superomedial portion is mainly innervated by the nerves to the vastus medialis and intermedius muscles (branches of the femoral nerve) and superior medial genicular nerve (a branch of the tibial nerve). The inferomedial portion is innervated by the inferior medial genicular nerve (a branch of the tibial nerve) and infrapatellar branch of the saphenous nerve (the terminal sensory branch of the femoral nerve). The superolateral portion is innervated by the nerves to the vastus lateralis and intermedius muscles (branches of the femoral nerve), common peroneal nerve, and superior lateral genicular nerve (a branch of the sciatic or common peroneal nerve). The inferolateral portion is innervated by the inferior lateral genicular nerve (a branch of the common peroneal nerve) and recurrent peroneal nerve (Figure 1) [12]. Figure 1 Open in new tabDownload slide Schematic drawing of the innervation of the anterior (left) and posterior (right) aspects of the knee. CPN = common peroneal nerve; ILG = inferior lateral genicular nerve; IMG = inferior medial genicular nerve; IPB = infrapatellar branch of the saphenous nerve; NVI = nerve to the vastus intermedius muscle; NVL = nerve to the vastus lateralis muscle; NVM = nerve to the vastus medialis muscle; PON = posterior branch of the obturator nerve; RPN = recurrent peroneal nerve; SAN = saphenous nerve; SCN = sciatic nerve; SLG = superior lateral genicular nerve; SMG = superior medial genicular nerve; TN = tibial nerve. Figure 1 Open in new tabDownload slide Schematic drawing of the innervation of the anterior (left) and posterior (right) aspects of the knee. CPN = common peroneal nerve; ILG = inferior lateral genicular nerve; IMG = inferior medial genicular nerve; IPB = infrapatellar branch of the saphenous nerve; NVI = nerve to the vastus intermedius muscle; NVL = nerve to the vastus lateralis muscle; NVM = nerve to the vastus medialis muscle; PON = posterior branch of the obturator nerve; RPN = recurrent peroneal nerve; SAN = saphenous nerve; SCN = sciatic nerve; SLG = superior lateral genicular nerve; SMG = superior medial genicular nerve; TN = tibial nerve. The posterior aspect of the knee joint is innervated by the sciatic, common peroneal, and tibial nerves and the posterior branch of the obturator nerve [13]. The posterolateral portion is innervated by the posterior articular branch of the sciatic and common peroneal nerves. The posteromedial and posterior intercondylar portions are innervated by the superior and inferior articular branches of the tibial nerve. The posterior branch of the obturator nerve gives off an articular branch, which courses through the adductor hiatus with the femoral artery and vein to innervate the popliteal fossa (Figure 1) [13,14]. Furthermore, if the physicians intend to treat the musculoskeletal component of knee pain, the branches innervating the knee capsule (the superior medial, inferior medial, superior lateral, and inferior lateral genicular nerves) and juxta-articular tendons (the infrapatellar branch of the saphenous nerve) can serve as the primary targets. On the other hand, if relief of postoperative knee pain is the major concern, the main trunks of the aforementioned nerves, such as the femoral and sciatic nerves, should be chosen for intervention. Sonoanatomy US is used as an imaging modality to scan the peripheral nerves. Most nerves in the extremities can be easily identified even on point-of-care US [15]. In the anterior aspect of the knee joint, the innervation is mainly mediated by the branches of the femoral nerve, which commonly serve as a target for PNS. To visualize the femoral nerve, the transducer should be placed along the inguinal crease on top of the pulsating femoral artery. The nerve is seen as a honeycomb structure lateral to the femoral artery, located in the groove formed by an intersection of the iliopsoas and pectineus muscles [15]. As detected with the transducer, the femoral nerve distally divides into several branches, such as branches to the vastus lateralis, intermedius, and medialis muscles and the saphenous nerve. The branches to the muscles can be tracked until they reach the corresponding muscle. The saphenous nerve courses medially with the superficial femoral artery to enter the adductor canal, bordered by the sartorius muscle superficially, vastus medialis muscle laterally, and adductor longus or magnus muscle deeply. After the saphenous nerve exits the adductor canal, it divides into the sartorial and infrapatellar branches [16], both of which run in the subcutaneous layer (Figure 2). Figure 2 Open in new tabDownload slide Ultrasound of the femoral nerve (white arrow) at the inguinal crease (A). The nerve to the vastus medialis muscle (black arrowhead) and saphenous nerve (black arrow) in the midthigh region (B). The infrapatellar branch of the saphenous nerve (yellow arrow) in the medial portion of the knee joint (C). The recurrent peroneal nerve (yellow arrowhead) in the proximal tibio-fibular joint (D). AL = adductor longus muscle; EDL = extensor digitorum longus muscle; FA = femoral artery; FE = femur; FI = fibula; IS = iliopsoas muscle; PC = pectineus muscle; SA = sartorius muscle; TA = tibialis anterior muscle; TI = tibia; VM = vastus medialis muscle. Figure 2 Open in new tabDownload slide Ultrasound of the femoral nerve (white arrow) at the inguinal crease (A). The nerve to the vastus medialis muscle (black arrowhead) and saphenous nerve (black arrow) in the midthigh region (B). The infrapatellar branch of the saphenous nerve (yellow arrow) in the medial portion of the knee joint (C). The recurrent peroneal nerve (yellow arrowhead) in the proximal tibio-fibular joint (D). AL = adductor longus muscle; EDL = extensor digitorum longus muscle; FA = femoral artery; FE = femur; FI = fibula; IS = iliopsoas muscle; PC = pectineus muscle; SA = sartorius muscle; TA = tibialis anterior muscle; TI = tibia; VM = vastus medialis muscle. Among the four genicular nerves, the superior medial genicular nerve is found lateral to the adductor magnus tendon, coursing around the corner of the femoral shaft and medial condyle [17]. The inferior medial genicular nerve is found passing the junction between the tibial plateau and its shaft underneath the pes anserinus tendon. The superior lateral genicular nerve is found at the corner, where the femoral shaft meets the lateral femoral condyle. The inferior lateral genicular nerve is found underneath the lateral collateral ligament of the knee, superficial to the lateral meniscus. The recurrent peroneal nerve is found deep in the extensor digitorum longus and tibialis anterior muscles and on top of the anterior tibio-fibular joint (Figure 3) [12]. The aforementioned nerves have accompanying arteries, which can readily be traced on Doppler US. Figure 3 Open in new tabDownload slide Ultrasound of the genicular nerves: superior medial (white arrow) (A), inferior medial (black arrow) (B), superior lateral (yellow arrow) (C), and inferior lateral (yellow arrowhead) (D). FE = femur; LCL = lateral collateral ligament; TI = tibia; VM = vastus medialis muscle. Figure 3 Open in new tabDownload slide Ultrasound of the genicular nerves: superior medial (white arrow) (A), inferior medial (black arrow) (B), superior lateral (yellow arrow) (C), and inferior lateral (yellow arrowhead) (D). FE = femur; LCL = lateral collateral ligament; TI = tibia; VM = vastus medialis muscle. The posterior aspect of the knee is mainly innervated by the branches of the sciatic nerve, which is also the primary target for PNS. To visualize the sciatic nerve, the transducer should be placed horizontally at the tip of the popliteal fossa [15]. The nerve is seen as a honeycomb structure interposed between the hamstring and adductor magnus muscles. As observed with the transducer, the sciatic nerve caudally divides into the tibial and common peroneal nerves. The tibial nerve is found descending with the popliteal artery, and the common peroneal nerve courses laterally in the fascial plane between the biceps femoris and lateral gastrocnemius muscles. The posterior branch of the obturator nerve can be tracked from the anterior aspect of the knee coursing between the adductor longus and magnus muscles in the distal portion of the femur and piercing the adductor hiatus to supply the popliteal fossa (Figure 4) [14]. Furthermore, the aforementioned nerves, especially for the smaller ones, should be double-confirmed by electric stimulation. Figure 4 Open in new tabDownload slide Ultrasound of the sciatic nerve (white arrow) in the posterior midthigh region (A). The tibial (black arrow) and common peroneal (black arrowhead) nerves at the edge of the popliteal fossa (B) and near the posterior knee joint line (C). The posterior branch of the obturator nerve (yellow arrow) in the distal portion of the femur (D). Figure 4 Open in new tabDownload slide Ultrasound of the sciatic nerve (white arrow) in the posterior midthigh region (A). The tibial (black arrow) and common peroneal (black arrowhead) nerves at the edge of the popliteal fossa (B) and near the posterior knee joint line (C). The posterior branch of the obturator nerve (yellow arrow) in the distal portion of the femur (D). Literature on PNS for Knee Pain Although the present article is a narrative review, we used a systematic approach to search for relevant articles. We used the combination of “peripheral nerve stimulation” and “knee pain” as the key words for the literature search using the PubMed electronic database without language or article type restriction. The search period was from the earliest record through August 2019. The present review focuses on specifically designed peripheral nerve stimulators (usually with an external pulse generator) instead of the spinal cord stimulator system (usually with an implantable pulse generator). Table 1 summarizes the details of each included study. Table 1 Summary of the included studies Author, Year, Journal . Study Design . Patient’s Characteristics . Number . Mean Age, y . Target Nerves . Treatment . Outcome . Adverse Effects . Ilfeld et al. 2017 [18], Pain Practice Case series Persistent pain after TKA 2 males, 3 females 53 Femoral and sciatic nerves Helically coiled monopolar-insulated electrical leads (MicroLead, SPR Therapeutics) connected to an external pulse stimulator used for 2 h Immediate pain relief at rest by 63%, during passive ROM by 14%, and during active ROM by 50% No device-related adverse events Ilfeld et al. 2017 [19], Journal of Orthopaedic Surgery and Research Case series Persistent pain after TKA 2 males, 3 females 60.8 Femoral and sciatic nerves Helically coiled monopolar-insulated electrical leads (MicroLead, SPR Therapeutics) connected to an external pulse stimulator used for 1–2 h Average pain decrease: 93% at rest, 27% at passive ROM, and 30% at active ROM No device-related adverse events Ilfeld et al. 2019 [20], Neuromodulation Case series Being scheduled to undergo primary unilateral TKA 3 males, 4 females 67.7 Femoral and sciatic nerves Helically coiled monopolar-insulated electrical leads (MicroLead, SPR Therapeutics) connected to an external pulse stimulator used both at home and in the hospital for up to 6 wk Postoperative pain <4/10 of NRS (N = 6), opioid discontinuation (N = 4), improvement of >10% on 6MWT and 95% on WOMAC at the 12-wk follow-up Discomfort (N = 1) and bruise (N = 1) over the implant site, nonspecific headache (N = 1), no serious device-related adverse events Ilfeld et al. 2019 [21], Neuromodulation Randomized, double-blinded, sham-controlled, partially crossover trial Being scheduled for ambulatory anterior cruciate ligament reconstruction 5 males, 5 females 25.0 Femoral nerve Helically coiled monopolar-insulated electrical leads (MicroLead, SPR Therapeutics) connected to an external pulse stimulator for 14–22 d after surgeries A mean decrease of pain of up to 84% from baseline during the subsequent 5 min with stimulation, use of rescue nerve block within 2 d postoperation (N = 8) No motor and sensory deficit in all patients Narouze et al. 2009 [22], Pain Physician Case report Intractable femoral neuropathy after cardiac catheterization 1 male 61.0 Femoral nerve Two percutaneous octad leads (Medtronics) connected to a rechargeable generator used for at least 20 mo Pain free for 20 mo after the implant with gradual taper of all pain medications No device-related adverse events Rauck et al. 2012 [23], Pain Practice Case report Severe residual limb pain following a below-knee amputation 1 female 49.0 Femoral nerve A fine-wire helical coiled lead connected to a regulated-voltage stimulator used for 2 wk A decrease of residual limb pain by 60% and painful disability by 74% No device-related adverse events Author, Year, Journal . Study Design . Patient’s Characteristics . Number . Mean Age, y . Target Nerves . Treatment . Outcome . Adverse Effects . Ilfeld et al. 2017 [18], Pain Practice Case series Persistent pain after TKA 2 males, 3 females 53 Femoral and sciatic nerves Helically coiled monopolar-insulated electrical leads (MicroLead, SPR Therapeutics) connected to an external pulse stimulator used for 2 h Immediate pain relief at rest by 63%, during passive ROM by 14%, and during active ROM by 50% No device-related adverse events Ilfeld et al. 2017 [19], Journal of Orthopaedic Surgery and Research Case series Persistent pain after TKA 2 males, 3 females 60.8 Femoral and sciatic nerves Helically coiled monopolar-insulated electrical leads (MicroLead, SPR Therapeutics) connected to an external pulse stimulator used for 1–2 h Average pain decrease: 93% at rest, 27% at passive ROM, and 30% at active ROM No device-related adverse events Ilfeld et al. 2019 [20], Neuromodulation Case series Being scheduled to undergo primary unilateral TKA 3 males, 4 females 67.7 Femoral and sciatic nerves Helically coiled monopolar-insulated electrical leads (MicroLead, SPR Therapeutics) connected to an external pulse stimulator used both at home and in the hospital for up to 6 wk Postoperative pain <4/10 of NRS (N = 6), opioid discontinuation (N = 4), improvement of >10% on 6MWT and 95% on WOMAC at the 12-wk follow-up Discomfort (N = 1) and bruise (N = 1) over the implant site, nonspecific headache (N = 1), no serious device-related adverse events Ilfeld et al. 2019 [21], Neuromodulation Randomized, double-blinded, sham-controlled, partially crossover trial Being scheduled for ambulatory anterior cruciate ligament reconstruction 5 males, 5 females 25.0 Femoral nerve Helically coiled monopolar-insulated electrical leads (MicroLead, SPR Therapeutics) connected to an external pulse stimulator for 14–22 d after surgeries A mean decrease of pain of up to 84% from baseline during the subsequent 5 min with stimulation, use of rescue nerve block within 2 d postoperation (N = 8) No motor and sensory deficit in all patients Narouze et al. 2009 [22], Pain Physician Case report Intractable femoral neuropathy after cardiac catheterization 1 male 61.0 Femoral nerve Two percutaneous octad leads (Medtronics) connected to a rechargeable generator used for at least 20 mo Pain free for 20 mo after the implant with gradual taper of all pain medications No device-related adverse events Rauck et al. 2012 [23], Pain Practice Case report Severe residual limb pain following a below-knee amputation 1 female 49.0 Femoral nerve A fine-wire helical coiled lead connected to a regulated-voltage stimulator used for 2 wk A decrease of residual limb pain by 60% and painful disability by 74% No device-related adverse events 6MWT = 6-Minute Walking Test; ROM = range of motion; TKA = total knee replacement; WOMAC = The Western Ontario and McMaster Universities Arthritis Index. Open in new tab Table 1 Summary of the included studies Author, Year, Journal . Study Design . Patient’s Characteristics . Number . Mean Age, y . Target Nerves . Treatment . Outcome . Adverse Effects . Ilfeld et al. 2017 [18], Pain Practice Case series Persistent pain after TKA 2 males, 3 females 53 Femoral and sciatic nerves Helically coiled monopolar-insulated electrical leads (MicroLead, SPR Therapeutics) connected to an external pulse stimulator used for 2 h Immediate pain relief at rest by 63%, during passive ROM by 14%, and during active ROM by 50% No device-related adverse events Ilfeld et al. 2017 [19], Journal of Orthopaedic Surgery and Research Case series Persistent pain after TKA 2 males, 3 females 60.8 Femoral and sciatic nerves Helically coiled monopolar-insulated electrical leads (MicroLead, SPR Therapeutics) connected to an external pulse stimulator used for 1–2 h Average pain decrease: 93% at rest, 27% at passive ROM, and 30% at active ROM No device-related adverse events Ilfeld et al. 2019 [20], Neuromodulation Case series Being scheduled to undergo primary unilateral TKA 3 males, 4 females 67.7 Femoral and sciatic nerves Helically coiled monopolar-insulated electrical leads (MicroLead, SPR Therapeutics) connected to an external pulse stimulator used both at home and in the hospital for up to 6 wk Postoperative pain <4/10 of NRS (N = 6), opioid discontinuation (N = 4), improvement of >10% on 6MWT and 95% on WOMAC at the 12-wk follow-up Discomfort (N = 1) and bruise (N = 1) over the implant site, nonspecific headache (N = 1), no serious device-related adverse events Ilfeld et al. 2019 [21], Neuromodulation Randomized, double-blinded, sham-controlled, partially crossover trial Being scheduled for ambulatory anterior cruciate ligament reconstruction 5 males, 5 females 25.0 Femoral nerve Helically coiled monopolar-insulated electrical leads (MicroLead, SPR Therapeutics) connected to an external pulse stimulator for 14–22 d after surgeries A mean decrease of pain of up to 84% from baseline during the subsequent 5 min with stimulation, use of rescue nerve block within 2 d postoperation (N = 8) No motor and sensory deficit in all patients Narouze et al. 2009 [22], Pain Physician Case report Intractable femoral neuropathy after cardiac catheterization 1 male 61.0 Femoral nerve Two percutaneous octad leads (Medtronics) connected to a rechargeable generator used for at least 20 mo Pain free for 20 mo after the implant with gradual taper of all pain medications No device-related adverse events Rauck et al. 2012 [23], Pain Practice Case report Severe residual limb pain following a below-knee amputation 1 female 49.0 Femoral nerve A fine-wire helical coiled lead connected to a regulated-voltage stimulator used for 2 wk A decrease of residual limb pain by 60% and painful disability by 74% No device-related adverse events Author, Year, Journal . Study Design . Patient’s Characteristics . Number . Mean Age, y . Target Nerves . Treatment . Outcome . Adverse Effects . Ilfeld et al. 2017 [18], Pain Practice Case series Persistent pain after TKA 2 males, 3 females 53 Femoral and sciatic nerves Helically coiled monopolar-insulated electrical leads (MicroLead, SPR Therapeutics) connected to an external pulse stimulator used for 2 h Immediate pain relief at rest by 63%, during passive ROM by 14%, and during active ROM by 50% No device-related adverse events Ilfeld et al. 2017 [19], Journal of Orthopaedic Surgery and Research Case series Persistent pain after TKA 2 males, 3 females 60.8 Femoral and sciatic nerves Helically coiled monopolar-insulated electrical leads (MicroLead, SPR Therapeutics) connected to an external pulse stimulator used for 1–2 h Average pain decrease: 93% at rest, 27% at passive ROM, and 30% at active ROM No device-related adverse events Ilfeld et al. 2019 [20], Neuromodulation Case series Being scheduled to undergo primary unilateral TKA 3 males, 4 females 67.7 Femoral and sciatic nerves Helically coiled monopolar-insulated electrical leads (MicroLead, SPR Therapeutics) connected to an external pulse stimulator used both at home and in the hospital for up to 6 wk Postoperative pain <4/10 of NRS (N = 6), opioid discontinuation (N = 4), improvement of >10% on 6MWT and 95% on WOMAC at the 12-wk follow-up Discomfort (N = 1) and bruise (N = 1) over the implant site, nonspecific headache (N = 1), no serious device-related adverse events Ilfeld et al. 2019 [21], Neuromodulation Randomized, double-blinded, sham-controlled, partially crossover trial Being scheduled for ambulatory anterior cruciate ligament reconstruction 5 males, 5 females 25.0 Femoral nerve Helically coiled monopolar-insulated electrical leads (MicroLead, SPR Therapeutics) connected to an external pulse stimulator for 14–22 d after surgeries A mean decrease of pain of up to 84% from baseline during the subsequent 5 min with stimulation, use of rescue nerve block within 2 d postoperation (N = 8) No motor and sensory deficit in all patients Narouze et al. 2009 [22], Pain Physician Case report Intractable femoral neuropathy after cardiac catheterization 1 male 61.0 Femoral nerve Two percutaneous octad leads (Medtronics) connected to a rechargeable generator used for at least 20 mo Pain free for 20 mo after the implant with gradual taper of all pain medications No device-related adverse events Rauck et al. 2012 [23], Pain Practice Case report Severe residual limb pain following a below-knee amputation 1 female 49.0 Femoral nerve A fine-wire helical coiled lead connected to a regulated-voltage stimulator used for 2 wk A decrease of residual limb pain by 60% and painful disability by 74% No device-related adverse events 6MWT = 6-Minute Walking Test; ROM = range of motion; TKA = total knee replacement; WOMAC = The Western Ontario and McMaster Universities Arthritis Index. Open in new tab Postoperative Pain In 2017, Ilfeld et al. [18] published a pilot single-arm study including five patients with persistent pain after total knee replacement. The femoral nerve at the inguinal crease and sciatic nerve in the subgluteal region were the main targets. Under real-time US (using the in-plane technique), the guiding needles were placed 0.5–1 cm from the femoral nerve and 1.0–3.0 cm from the sciatic nerve. PNS was performed using a monopolar, helically coiled, insulated lead (MicroLead, SPR Therapeutics, Cleveland, OH, USA), which was subsequently connected to an external stimulator. The outcome was evaluated within two hours of the initiation of PNS. The leads were removed two hours after the test. The result revealed a 63% decrease in pain at rest, a 14% decrease in pain during passive motion, and a 50% decrease in pain during active movements. In the same year, Ilfeld et al. [19] published another case series with similar inclusion criteria as the aforementioned study [18]. The other five patients underwent percutaneous US-guided PNS for the femoral and sciatic nerves within 60 days of total knee replacement. Pain relief was observed immediately after PNS, with a mean decrease in the numeric rating scale score for pain by 93%. Four of the five patients reported complete resolution of pain. In 2019, Ilfeld et al. [20] performed a pilot study examining the feasibility of PNS in the perioperative period, immediately after total knee arthroplasty (within 20 hours of the surgery). Similar to previous studies, the femoral and sciatic nerves were stimulated. The leads were used both at home and in the hospital for up to six weeks. Seven patients were included, and six of them experienced postoperative pain with a numerical rating scale score of <4/10. Opioid use was discontinued by four patients within one week of surgery. At the 12-week follow-up, six of the seven subjects reported an improvement of >10% on the 6-Minute Walk Test and of ∼85% on the Western Ontario and McMaster Universities Osteoarthritis Index in comparison with baseline. In 2019, the same team conducted a randomized, double-blinded, sham-controlled, partial crossover trial, targeting patients who underwent ambulatory anterior cruciate ligament reconstruction [21]. Ten participants were allocated into two groups and sequentially administered five minutes of PNS to the femoral nerve and five minutes of sham stimulation or vice versa soon after the surgery. Subsequently, a continuous active stimulation was performed in patients of both groups until 2–4 postoperative weeks. The outcome showed that the patients who underwent PNS first had a mild (∼7%) decrease in pain, and those who underwent sham therapy had a slight increase (4%) in pain over the first five minutes of stimulation. Both groups showed a mean decrease in pain of up to 84% from baseline (N = 10) after the subsequent five minutes of stimulation. For two postoperative days, eight patients used the continuous adductor canal nerve block for rescue analgesia for at least 10 minutes every day. None of the aforementioned studies had patients with motor or sensory deficits due to PNS. Neuropathic Pain In 2009, Narouze et al. [22] reported a case of intractable neuropathic pain in a 61-year-old man in the region supplied by the femoral nerve after sustaining an injury during cardiac catheterization. Two percutaneous leads (Medtronics, Minneapolis, MN, USA) were placed under US guidance in proximity to the femoral nerves. A test stimulation was administered to confirm analgesia in the area innervated by the saphenous nerve. The location of the leads was also confirmed on fluoroscopy. The patient reported a 20-month pain-free period after the intervention and stopped taking pain medication. In 2012, Rauck et al. [23] reported a case of residual limb pain (≥4 out of 11 on the numerical rating scale) after a below-knee amputation in a 49-year-old woman following a traffic accident 33 years before. A monopolar needle electrode (Jari Electrode Supply, Gilroy, CA, USA) was inserted distal to the inguinal crease and at a distance of 0.5–1 cm lateral to the femoral nerve under US guidance. The lead was properly positioned through induction of comfortable paresthesia with stimulation of the painful area (>75%) without muscle contractions. She described a significant decrease in residual limb pain (60%) and painful disability (74%) after 2 weeks of PNS. Discussion In our literature search, we found that most studies on the use of PNS to manage knee pain were case series or case reports [18–23]. There is a lack of comparison studies to show whether PNS is better than placebo or other common approaches. Although one study employed a randomized controlled partial crossover design, the sample size for each treatment arm was small [19]. Additionally, none of the included studies measured the effect size. Therefore, the evidence is limited to measure the magnitude of improvement in pain after PNS. However, PNS is feasible for the management of postoperative and recalcitrant chronic knee pain. Under US guidance, the nerves can be located precisely, and the electrodes can be placed safely at the most effective locations for PNS. Thus, no collateral neurovascular damage was reported in the reviewed studies. Further, the femoral and sciatic nerves are the main targets for PNS in the knees. Based on the previous reviews of knee innervation [12,13], the femoral and sciatic nerves carry nearly all sensory innervations from the knee joint, except for a small portion in the posterior portion of the knee (supplied by the posterior branch of the obturator nerve). In our review, we did not identify any report of discomfort of the calf or ankle following stimulation of the femoral and sciatic nerves. This outcome might be related to the single coiled monopolar lead used in most of our included trials. This specifically designed lead enables selective activation of large-diameter myelinated fibers instead of stimulating small-diameter nonmyelinated fibers, which primarily convey nociception and autonomic impulses [11]. Finally, there are no trials examining the feasibility of PNS on smaller genicular nerves in patients with knee osteoarthritis. Considering the high prevalence of knee OA, future studies are warranted to evaluate whether PNS is beneficial for pain management in knee osteoarthritis. Although there is no direct evidence of PNS for chronic knee pain, we would like to make some recommendations of potential targets for intervention. In patients with knee pain mostly limited at its anterior medial aspect, physicians can probe the femoral nerve to cover the area innervated by the saphenous nerve. If patients complain of widespread pain inside the knee joint, the sciatic nerve (serving as the proximal trunk of nearly all the genicular nerves) should be treated as the primary focus of PNS. Conclusions The present review reveals that PNS is feasible for the management of knee pain, especially in the postoperative period. The procedure is safe under US guidance used for proper placement of the electrodes near the target nerves. In the future, more prospective randomized controlled trials are needed to validate the effectiveness of PNS in acute and chronic knee pain. Funding sources: The current research project was supported by Bioness, Inc. (Valencia, CA, USA) and SPR Therapeutics, Inc. (Cleveland, OH, USA). Conflicts of interest: All authors declared no conflicts of interest. Supplement sponsorship: This article appears as part of the supplement entitled “Peripheral Nerve Stimulation: Update for the 21st Century” sponsored by Bioness and by SPR Therapeutics, Inc. References 1 Nguyen US , Zhang Y, Zhu Y, Niu J, Zhang B, Felson DT. Increasing prevalence of knee pain and symptomatic knee osteoarthritis: Survey and cohort data . Ann Intern Med 2011 ; 155 ( 11 ): 725 – 32 . OpenURL Placeholder Text WorldCat 2 Kim IJ , Kim HA, Seo YI, Jung YO, et al. . Prevalence of knee pain and its influence on quality of life and physical function in the Korean elderly population: A community based cross-sectional study . J Korean Med Sci 2011 ; 26 ( 9 ): 1140 – 6 . OpenURL Placeholder Text WorldCat 3 Hussain SM , Neilly DW, Baliga S, Patil S, Meek R. Knee osteoarthritis: A review of management options . Scott Med J 2016 ; 61 ( 1 ): 7 – 16 . OpenURL Placeholder Text WorldCat 4 Chang KV , Hung CY, Aliwarga F, Wang TG, Han DS, Chen WS. Comparative effectiveness of platelet-rich plasma injections for treating knee joint cartilage degenerative pathology: A systematic review and meta-analysis . Arch Phys Med Rehabil 2014 ; 95 ( 3 ): 562 – 75 . OpenURL Placeholder Text WorldCat 5 Palmer JS , Monk AP, Hopewell S, et al. . Surgical interventions for symptomatic mild to moderate knee osteoarthritis . Cochrane Database Syst Rev 2019 ; 7 : CD012128 . OpenURL Placeholder Text WorldCat 6 Lim HA , Song EK, Seon JK, Park KS, Shin YJ, Yang HY. Causes of aseptic persistent pain after total knee arthroplasty . Clin Orthop Surg 2017 ; 9 ( 1 ): 50 – 6 . OpenURL Placeholder Text WorldCat 7 Karlsen AP , Wetterslev M, Hansen SE, Hansen MS, Mathiesen O, Dahl JB. Postoperative pain treatment after total knee arthroplasty: A systematic review . PLoS One 2017 ; 12 ( 3 ): e0173107. OpenURL Placeholder Text WorldCat 8 Ilfeld BM. Continuous peripheral nerve blocks: A review of the published evidence . Anesth Analg 2011 ; 113 ( 4 ): 904 – 25 . OpenURL Placeholder Text WorldCat 9 Nayak R , Banik RK. Current innovations in peripheral nerve stimulation . Pain Res Treat 2018 ; 2018 : 9091216. OpenURL Placeholder Text WorldCat 10 Wu W-T , Chang K-V, Mezian K, Naňka O, Lin C-P, Özçakar L. Basis of shoulder nerve entrapment syndrome: An ultrasonographic study exploring factors influencing cross-sectional area of the suprascapular nerve . Front Neurol 2018 ; 9 : 902 . OpenURL Placeholder Text WorldCat 11 Ilfeld BM , Ball ST, Cohen SP, et al. . Percutaneous peripheral nerve stimulation to control postoperative pain, decrease opioid use, and accelerate functional recovery following orthopedic trauma . Mil Med 2019 ; 184 ( Suppl 1 ): 557 – 64 . OpenURL Placeholder Text WorldCat 12 Tran J , Peng PWH, Lam K, Baig E, Agur AMR, Gofeld M. Anatomical study of the innervation of anterior knee joint capsule: Implication for image-guided intervention . Reg Anesth Pain Med 2018 ; 43 ( 4 ): 407 – 14 . OpenURL Placeholder Text WorldCat 13 Tran J , Peng PWH, Gofeld M, Chan V, Agur A. Anatomical study of the innervation of posterior knee joint capsule: Implication for image-guided intervention . Reg Anesth Pain Med 2019 ; 44 ( 2 ): 234 – 8 . OpenURL Placeholder Text WorldCat 14 Runge C , Moriggl B, Borglum J, Bendtsen TF. The spread of ultrasound-guided injectate from the adductor canal to the genicular branch of the posterior obturator nerve and the popliteal plexus: A cadaveric study . Reg Anesth Pain Med 2017 ; 42 ( 6 ): 725 – 30 . OpenURL Placeholder Text WorldCat 15 Hung CY , Hsiao MY, Ozcakar L, et al. . Sonographic tracking of the lower limb peripheral nerves: A pictorial essay and video demonstration . Am J Phys Med Rehabil 2016 ; 95 ( 9 ): 698 – 708 . OpenURL Placeholder Text WorldCat 16 Chang KV , Mezian K, Nanka O, et al. . Ultrasound imaging for the cutaneous nerves of the extremities and relevant entrapment syndromes: From anatomy to clinical implications . J Clin Med 2018 ; 7 ( 11 ). OpenURL Placeholder Text WorldCat 17 Yasar E , Kesikburun S, Kılıç C, Güzelküçük Ü, Yazar F, Tan AK. Accuracy of ultrasound-guided genicular nerve block: A cadaveric study . Pain Phys 2015 ; 18 ( 5 ): E899 – 904 . OpenURL Placeholder Text WorldCat 18 Ilfeld BM , Grant SA, Gilmore CA, et al. . Neurostimulation for postsurgical analgesia: A novel system enabling ultrasound-guided percutaneous peripheral nerve stimulation . Pain Pract 2017 ; 17 ( 7 ): 892 – 901 . OpenURL Placeholder Text WorldCat 19 Ilfeld BM , Gilmore CA, Grant SA, et al. . Ultrasound-guided percutaneous peripheral nerve stimulation for analgesia following total knee arthroplasty: A prospective feasibility study . J Orthop Surg Res 2017 ; 12 ( 1 ): 4. OpenURL Placeholder Text WorldCat 20 Ilfeld BM , Ball ST, Gabriel RA, et al. . A feasibility study of percutaneous peripheral nerve stimulation for the treatment of postoperative pain following total knee arthroplasty . Neuromodulation 2019 ; 22 ( 5 ): 653 – 60 . OpenURL Placeholder Text WorldCat 21 Ilfeld BM , Said ET, Finneran JJ 4th, et al. . Ultrasound-guided percutaneous peripheral nerve stimulation: Neuromodulation of the femoral nerve for postoperative analgesia following ambulatory anterior cruciate ligament reconstruction: A proof of concept study . Neuromodulation 2019 ; 22 ( 5 ): 621 – 9 . OpenURL Placeholder Text WorldCat 22 Narouze SN , Zakari A, Vydyanathan A. Ultrasound-guided placement of a permanent percutaneous femoral nerve stimulator leads for the treatment of intractable femoral neuropathy . Pain Phys 2009 ; 12 ( 4 ): E305 – 8 . OpenURL Placeholder Text WorldCat 23 Rauck RL , Kapural L, Cohen SP, et al. . Peripheral nerve stimulation for the treatment of postamputation pain—a case report . Pain Pract 2012 ; 12 ( 8 ): 649 – 55 . OpenURL Placeholder Text WorldCat © The Author(s) 2020. Published by Oxford University Press on behalf of the American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)
TI - Ultrasound-Guided Peripheral Nerve Stimulation for Knee Pain: A Mini-Review of the Neuroanatomy and the Evidence from Clinical Studies
JF - Pain Medicine
DO - 10.1093/pm/pnz318
DA - 2020-08-01
UR - https://www.deepdyve.com/lp/oxford-university-press/ultrasound-guided-peripheral-nerve-stimulation-for-knee-pain-a-mini-Ar4TjYHv2l
SP - S56
EP - S63
VL - 21
IS - Supplement_1
DP - DeepDyve
ER -