TY - JOUR
AU - Muizelaar, Jan Paul
AB - ABSTRACT BACKGROUND AND IMPORTANCE Tethered cord syndrome (TCS) often leads to severe back and leg pain. The typical treatment to stall disease progression is untethering surgery, but this is not always effective for pain. Spinal cord stimulation (SCS) is an efficacious treatment for neuropathic pain. However, it has seldom been utilized in TCS cases. Moreover, with cord elongation, ideal paddle placement is not certain. CLINICAL PRESENTATION We present the case of a 77-yr-old male with severe chronic lower-back and lower-extremity pain. Magnetic resonance imaging (MRI) showed severe lumbar spine degenerative changes, along with a previously undiagnosed spina bifida and conus medullaris termination at L5. We felt that SCS would be the best treatment avenue for his chief complaint of pain. Due to cord elongation, we trialed lower placement of the high-frequency (HF)-SCS system at T11-T12, which led to 80% improvement in pain symptoms within 1 wk and ability to walk for the first time in a year. At his first follow-up appointment, the patient endorsed 80% to 90% relief of his lower-back and bilateral lower-extremity pain, which improved to 100% relief at 12 mo at last visit. CONCLUSION Only 4 other reports were identified in the literature utilizing SCS in TCS cases. Our case adds to the limited body of literature that SCS is an effective therapy for pain in TCS and degenerative spine disease. Only 2 other reports employed lower than usual lead placement. Our case demonstrates that lead placement may need to be changed to accommodate the elongated cord. Lipomyelomeningocele, Spinal cord stimulator, Tethered cord syndrome, Unusual placement, Case report ABBREVIATIONS ABBREVIATIONS HF high frequency LMM lipomyelomeningocele SCS spinal cord stimulation TCS tethered cord syndrome Tethered cord syndrome (TCS) is a clinical entity characterized by excessive tension on the spinal cord, leading to a constellation of neurological symptoms.1-3 The cord is usually tethered in the lumbosacral region, causing an anatomically lower position of the conus medullaris and thoracolumbar cord segments.1 Symptoms typically appear during childhood, but some individuals remain asymptomatic until adulthood.1,4 These patients present with worsening symptoms, particularly nondermatomal back or leg pain.1,5,6 Detethering surgery is the definitive treatment to obviate progression of neurological symptoms; however, many patients have persistent neuropathic pain.4 Spinal cord stimulation (SCS) can be successfully utilized for various causes of neuropathic pain,7 and has been previously, albeit rarely, reported for TCS.4,5,7-9 Herein, we present the case of a patient with previously undiagnosed TCS with severe back and leg pain, which was treated with SCS, culminating in near total alleviation of his pain. Importantly, due to more caudal termination of the conus, a more inferior than usual SCS placement was performed, suggesting that SCS utilization in TCS requires differing placement. CLINICAL PRESENTATION A 77-yr-old male presented to the neurosurgery clinic for the evaluation of chronic lower-back pain. He has had ongoing severe pain for several years, but it has amplified over the past year and made him wheelchair bound. His symptoms are characterized by lower-back pain radiating into bilateral lower extremities, more commonly right sided, and associated bilateral lower-extremity weakness. He rates the pain 9/10 in intensity, and states that it is aching, burning, stabbing, and constant in nature. The patient has had many types of prior nonsurgical treatments. He previously had a bladder stimulator implanted, which was helpful for pain in the rectal area, but was removed due to magnetic resonance imaging (MRI) incompatibility. Neurological examination was characterized mostly by decreased sensation to light touch in distal bilateral lower extremities as well as a sacral dimple. Lumbar MRI showed many signs of multilevel degenerative disease, plus a tethered cord and a lipomyelomeningocele (LMM) (Figure 1). We discussed with the patient that we felt his chief complaint of pain was likely due to the combination of TCS and degenerative spine disease, and SCS implantation would possibly alleviate his suffering irrespective of the exact cause, while avoiding extensive spine surgery. FIGURE 1. Open in new tabDownload slide A T2-weighted sagittal lumbar MRI displays multilevel degenerative changes of the lumbar spine throughout, with vertebral height loss at L4, acute on chronic endplate changes at L3/L4 and L4/L5, disc osteophyte complex formation at L4-L5 with moderate canal stenosis, and disc osteophyte complex formation at L5-S1 with moderate to severe foraminal narrowing. It also displays termination of the conus medullaris at L5 due to spina bifida at L5-S1. FIGURE 1. Open in new tabDownload slide A T2-weighted sagittal lumbar MRI displays multilevel degenerative changes of the lumbar spine throughout, with vertebral height loss at L4, acute on chronic endplate changes at L3/L4 and L4/L5, disc osteophyte complex formation at L4-L5 with moderate canal stenosis, and disc osteophyte complex formation at L5-S1 with moderate to severe foraminal narrowing. It also displays termination of the conus medullaris at L5 due to spina bifida at L5-S1. Patient elected to proceed with an SCS trial. Due to his conus medullaris terminating at L5 and associated stretching of the spinal cord, a decision was made to place the stimulator paddle at T11-T12, rather than the usual T9-T10 (Figure 2). The stimulator trial ameliorated his pain by 80%, allowing unassisted walking for the first time in a year, so permanent implantation of the pulse generator followed. At his first follow-up appointment, the patient endorsed 80% to 90% relief of his lower-back and leg pain, which improved to 100% improvement at last follow-up at 12 mo. The patient consented to drafting of this manuscript and presentation of his case. FIGURE 2. Open in new tabDownload slide Intraoperative fluoroscopic imaging of the upper lumbar spine displays paddle placement centered over the T11-T12 disc space. FIGURE 2. Open in new tabDownload slide Intraoperative fluoroscopic imaging of the upper lumbar spine displays paddle placement centered over the T11-T12 disc space. DISCUSSION Herein we present a unique case of a patient with TCS, which was previously undiagnosed through >70 yr of life, whose pain was successfully treated with SCS. The SCS paddle placement at T11-T12 was 2 levels lower than typical positioning, which we hypothesized would be effective given the elongated cord and conus termination at L5. In cases of TCS, maximal cord elongation occurs at the lumbosacral region, with some elongation in the thoracic area, and minimal to none in cervical regions.8-10 Thus, this was taken into account on the decision of placement level, and is also consistent with the literature.4,8 On the other hand, the epidural paddle is so long that in the case of lack of effect, higher- or lower-placed electrodes could be tried. Our case adds to the paucity of literature pertaining to SCS utilization for TCS patients; only 4 total reports were identified in the literature, with 6 total TCS patients successfully treated with SCS, and only 1 treatment failure.4,5,8,9 There are crucial differences between our case and the previous cases. Ours is the first to utilize the high-frequency (HF)-SCS system, which a randomized trial demonstrated to be more effective.11 Based on seminal paresthesia mapping by Barolat and colleagues,12 T7-T10 vertebral levels displayed the highest percentage of body surface coverage by stimulation, although there was significant variability. As placement is idiosyncratic, there is no established vertebral level target per se, but the most common targets for lower-back and leg pain follow Barolat et al,12 and are between T7 and T11, with large variations in placement across centers, individuals, and stimulator systems.13-16 In contrast, the HF-SCS system is always placed anatomically, centered over the T9-T10 disc space.17,18 This is important, as both Moens et al8 and Novik et al4 placed the paddles at lower vertebral levels (T11-T12 and L1, respectively) due to the lower-lying conus, which was confirmed as ideal placement with the results of intraoperative paresthesia mapping or neuromonitoring. Crucially, though placement was changed to accommodate the unique anatomy of TCS, both locations are within normal ranges of paddle placement utilizing those systems. Our case is the first to adjust placement of the HF-SCS system with significant effectiveness, suggesting feasibility in TCS cases. Consistent with previous reports,4,5,8 our patient had an LMM. Moreover, the patient's main complaint was severe pain, with a nondermatomal burning quality, which is congruent with the preponderance of TCS cases and previous reports.1,4,6 In contrast, our patient was the only identified case where no previous diagnosis of LMM and TCS was made, and in which no prior untethering surgery was attempted.4,5,8,9 The degree of cord traction rather than the level of tethering or type of lesion is the principal factor related to symptom onset.1 The development of spinal stenosis can accentuate tension on the cord and lead to a delayed onset of symptoms,1 which our patient had. CONCLUSION The implications of this report are two-fold. First, in keeping with prior reports, SCS can be highly efficacious for pain relief in patients with a combination of long-standing TCS and degenerative spine disease. Secondly, in patients with TCS, ideal lead placement may need to be moved to lower vertebral levels. Funding This study did not receive any funding or financial support. Disclosures The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article. REFERENCES 1. Hertzler DA 2nd, DePowell JJ, Stevenson CB, Mangano FT. Tethered cord syndrome: a review of the literature from embryology to adult presentation . Neurosurg Focus . 2010 ; 29 ( 1 ): E1 . Google Scholar Crossref Search ADS PubMed WorldCat 2. Lew SM , Kothbauer KF. Tethered cord syndrome: an updated review . Pediatr Neurosurg . 2007 ; 43 ( 3 ): 236 - 248 . Google Scholar Crossref Search ADS PubMed WorldCat 3. Agarwalla PK , Dunn IF, Scott RM, Smith ER. Tethered cord syndrome . Neurosurg Clin N Am . 2007 ; 18 ( 3 ): 531 - 547 . Google Scholar Crossref Search ADS PubMed WorldCat 4. Novik Y , Vassiliev D, Tomycz ND. 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Zan E , Kurt KN, Yousem DM, Christo PJ. Spinal cord stimulators: typical positioning and postsurgical complications . Am J Roentgenol . 2011 ; 196 ( 2 ): 437 - 445 . Google Scholar Crossref Search ADS WorldCat 17. Russo M , Van Buyten JP. 10-kHz high-frequency SCS therapy: a clinical summary . Pain Med . 2015 ; 16 ( 5 ): 934 - 942 . Google Scholar Crossref Search ADS PubMed WorldCat 18. Sayed D , Kallewaard JW, Rotte A, Jameson J, Caraway D. Pain relief and improvement in quality of life with 10 kHz SCS therapy: summary of clinical evidence . CNS Neurosci Ther . 2020 ; 26 ( 4 ): 403 - 415 . Google Scholar Crossref Search ADS PubMed WorldCat COMMENTS The authors present the case of a 77-year-old male with severe chronic lower-back and lower extremity pain with previously undiagnosed spina bifida and conus medullaris termination at L5. A trial of spinal cord stimulation (SCS) was elected to alleviate the pain symptoms. The results were impressive after the placement of high-frequency-SCS system at T11-T12 (lower thoracic level), which led to an 80% improvement in pain symptoms within one week. In addition, the patient endorsed 80%-90% relief of his lower-back and bilateral lower extremity pain at the first follow-up appointment. These symptoms improved to 100% relief at the 12 month follow up. As intradural detethering surgeries might carry significant risk of complications (cerebrospinal fluid leak, more pain, etc), the use of SCS is considered a feasible alternative to improve the neurological function. This study demonstrates the importance of the high frequency SCS compared to traditional low frequency SCS focusing on the treatment of patients with TSC (tethered spinal cord). This is a promising and innovative use of SCS and open new therapeutic possibilities for patients with this condition. Mohamad Bydon Rochester, Minnesota The authors of this interesting report were able to obtain lasting control of chronic low-back pain in an elderly patient with multi-level degenerative spine disease and a combination of intradural lipoma and tethered spinal cord. Although I feel that the tethered cord and lipoma most likely were asymptomatic and the pain was caused by progression of the degenerative spondylosis, the ability of high-frequency spinal cord stimulation (SCS) to result in significant reduction (and eventual resolution) of pain along with associated functional improvement is indeed impressive. As the matter of fact, the use of high frequency SCS for non-surgical low back pain is now a subject detailed investigation – and therefore it may be especially important to pay attention to the authors’ point on individual tailoring of the spinal level at which one should put the stimulating electrodes. Perhaps this information may be used by future implanters to justify proper pre-operative imaging in SCS candidates, not only for ruling out correctable pain sources but also to define optimal location of SCS electrodes. Konstantin Slavin Chicago, Illinois Copyright © The Author(s) 2021. Published by Oxford University Press on behalf of the Congress of Neurological Surgeons. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com
TI - Successful Treatment of Chronic Back and Leg Pain With Lower Than Usual Placement of High-Frequency Spinal Cord Stimulation in a Patient With Uncorrected Tethered Cord: Case Report
JF - Neurosurgery Open
DO - 10.1093/neuopn/okab012
DA - 2021-04-04
UR - https://www.deepdyve.com/lp/oxford-university-press/successful-treatment-of-chronic-back-and-leg-pain-with-lower-than-XMhIv6FsH7
VL - 2
IS - 2
DP - DeepDyve
ER -