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Laura Bloom, S. Shelby Burks, and Allan D. Levi

Postoperative wound infections in spinal surgery remain an important complication to diagnose and treat successfully. In most cases of deep infection, even with instrumentation, aggressive soft-tissue debridement followed by intravenous antibiotics is sufficient. This report presents a patient who underwent L3–S1 laminectomy and pedicle screw placement including bicortical sacral screws. This patient went on to develop multiple (7) recurrent infections at the operative site over a 5-year period. Continued investigation eventually revealed a large presacral abscess, which remained the source of recurrent bacterial seeding via the remaining bone tracts of the bicortical sacral screws placed during the original lumbar surgery. Two years after drainage of this presacral collection via a retroperitoneal approach, the patient remains symptom free.

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S. Shelby Burks, David J. Levi, Seth Hayes, and Allan D. Levi

Object

The object of this study was to highlight the challenge of insufficient donor graft material in peripheral nerve surgery, with a specific focus on sciatic nerve transection requiring autologous sural nerve graft.

Methods

The authors performed an anatomical analysis of cadaveric sciatic and sural nerve tissue. To complement this they also present 3 illustrative clinical cases of sciatic nerve injuries with segmental defects. In the anatomical study, the cross-sectional area (CSA), circumference, diameter, percentage of neural tissue, fat content of the sural nerves, as well as the number of fascicles, were measured from cadaveric samples. The percentage of neural tissue was defined as the CSA of fascicles lined by perineurium relative to the CSA of the sural nerve surrounded by epineurium.

Results

Sural nerve samples were obtained from 8 cadaveric specimens. Mean values and standard deviations from sural nerve measurements were as follows: CSA 2.84 ± 0.91 mm2, circumference 6.67 ± 1.60 mm, diameter 2.36 ± 0.43 mm, fat content 0.83 ± 0.91 mm2, and number of fascicles 9.88 ± 3.68. The percentage of neural tissue seen on sural nerve cross-section was 33.17% ± 4.96%. One sciatic nerve was also evaluated. It had a CSA of 37.50 mm2, with 56% of the CSA representing nerve material. The estimated length of sciatic nerve that could be repaired with a bilateral sural nerve harvest (85 cm) varied from as little as 2.5 cm to as much as 8 cm.

Conclusions

Multiple methods have been used in the past to repair sciatic nerve injury but most commonly, when a considerable gap is present, autologous nerve grafting is required, with sural nerve being the foremost source. As evidenced by the anatomical data reported in this study, a considerable degree of variability exists in the diameter of sural nerve harvests. Conversely, the percentage of neural tissue is relatively consistent across specimens. The authors recommend that the peripheral nerve surgeon take these points into consideration during nerve grafting as insufficient graft material may preclude successful recovery.

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Timur M. Urakov, Ken Hsuan-kan Chang, S. Shelby Burks, and Michael Y. Wang

OBJECTIVE

Spine surgery is complex and involves various steps. Current robotic technology is mostly aimed at assisting with pedicle screw insertion. This report evaluates the feasibility of robot-assisted pedicle instrumentation in an academic environment with the involvement of residents and fellows.

METHODS

The Renaissance Guidance System was used to plan and execute pedicle screw placement in open and percutaneous consecutive cases performed in the period of December 2015 to December 2016. The database was reviewed to assess the usability of the robot by neurosurgical trainees. Outcome measures included time per screw, fluoroscopy time, breached screws, and other complications. Screw placement was assessed in patients with postoperative CT studies. The speed of screw placement and fluoroscopy time were collected at the time of surgery by personnel affiliated with the robot’s manufacturer. Complication and imaging data were reviewed retrospectively.

RESULTS

A total of 306 pedicle screws were inserted in 30 patients with robot guidance. The average time for junior residents was 4.4 min/screw and for senior residents and fellows, 4.02 min/screw (p = 0.61). Among the residents dedicated to spine surgery, the average speed was 3.84 min/screw, while nondedicated residents took 4.5 min/screw (p = 0.41). Evaluation of breached screws revealed some of the pitfalls in using the robot.

CONCLUSIONS

No significant difference regarding the speed of pedicle instrumentation was detected between the operators’ years of experience or dedication to spine surgery, although more participants are required to investigate this completely. On the other hand, there was a trend toward improved efficiency with more cases performed. To the authors’ knowledge, this is the first reported academic experience with robot-assisted spine instrumentation.

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Joshua Zeidenberg, S. Shelby Burks, Jean Jose, Ty K. Subhawong, and Allan D. Levi

Ultrasound technology continues to improve with better image resolution and availability. Its use in evaluating peripheral nerve lesions is increasing. The current review focuses on the utility of ultrasound in traumatic injuries. In this report, the authors present 4 illustrative cases in which high-resolution ultrasound dramatically enhanced the anatomical understanding and surgical planning of traumatic peripheral nerve lesions. Cases include a lacerating injury of the sciatic nerve at the popliteal fossa, a femoral nerve injury from a pseudoaneurysm, an ulnar nerve neuroma after attempted repair with a conduit, and, finally, a spinal accessory nerve injury after biopsy of a supraclavicular fossa lesion. Preoperative ultrasound images and intraoperative pictures are presented with a focus on how ultrasound aided with surgical decision making. These cases are set into context with a review of the literature on peripheral nerve ultrasound and a comparison between ultrasound and MRI modalities.

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S. Shelby Burks, Juan S. Uribe, John Paul G. Kolcun, Adisson Fortunel, Jakub Godzik, Konrad Bach, and Michael Y. Wang

OBJECTIVE

Minimally invasive techniques are increasingly used in adult deformity surgery as surgeon familiarity improves and long-term data are published. Concerns raised in such cases include pseudarthrosis at levels where interbody grafts are not utilized. Few previous studies have specifically examined the thoracolumbar component of long surgical constructs, which is commonly instrumented without interbody or intertransverse fusion.

METHODS

A retrospective analysis was performed on all patients who underwent hybrid minimally invasive deformity corrections in two academic spine centers over a 9-year period. Inclusion criteria were at least 2 rostral levels instrumented percutaneously, ranging from T8 to L1 as the upper end of the construct. Fusion assessment was made using CT when possible or radiography. Common radiographic parameters and clinical variables were assessed pre- and postoperatively.

RESULTS

A total of 36 patients fit the inclusion criteria. Baseline characteristics included a 1:1.8 male/female ratio, average age of 65.7 years, and BMI of 30.2 kg/m2. Follow-up imaging was obtained at a mean of 35.7 months. The average number of levels fused was 7.5, with an average of 3.4 instrumented percutaneously between T8 and L1, representing a total of 120 rostral levels instrumented percutaneously. Fusion assessment was performed using CT in 69 levels and radiography in 51 levels. Among the 120 rostral levels instrumented percutaneously, robust fusion was noted in 25 (20.8%), with 53 (44.2%) exhibiting some evidence of fusion. Pseudarthrosis was noted in 2 rostral segments (1.7%). There were no instances of proximal hardware revision. Eight patients exhibited radiographic proximal junctional kyphosis (PJK; 22.2%), none of whom underwent surgical intervention.

CONCLUSIONS

In the present series of adult patients with scoliosis undergoing thoracolumbar deformity correction, rostral segments instrumented percutaneously have a very low rate of pseudarthrosis, with radiographic evidence of bone fusion occurring in more than 60% of patients. The rate of PJK was acceptable and similar to other published series.

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Zachary C. Gersey, S. Shelby Burks, Kim D. Anderson, Marine Dididze, Aisha Khan, W. Dalton Dietrich, and Allan D. Levi

OBJECTIVE

Long-segment injuries to large peripheral nerves present a challenge to surgeons because insufficient donor tissue limits repair. Multiple supplemental approaches have been investigated, including the use of Schwann cells (SCs). The authors present the first 2 cases using autologous SCs to supplement a peripheral nerve graft repair in humans with long-term follow-up data.

METHODS

Two patients were enrolled in an FDA-approved trial to assess the safety of using expanded populations of autologous SCs to supplement the repair of long-segment injuries to the sciatic nerve. The mechanism of injury included a boat propeller and a gunshot wound. The SCs were obtained from both the sural nerve and damaged sciatic nerve stump. The SCs were expanded and purified in culture by using heregulin β1 and forskolin. Repair was performed with sural nerve grafts, SCs in suspension, and a Duragen graft to house the construct. Follow-up was 36 and 12 months for the patients in Cases 1 and 2, respectively.

RESULTS

The patient in Case 1 had a boat propeller injury with complete transection of both sciatic divisions at midthigh. The graft length was approximately 7.5 cm. In the postoperative period the patient regained motor function (Medical Research Council [MRC] Grade 5/5) in the tibial distribution, with partial function in peroneal distribution (MRC Grade 2/5 on dorsiflexion). Partial return of sensory function was also achieved, and neuropathic pain was completely resolved. The patient in Case 2 sustained a gunshot wound to the leg, with partial disruption of the tibial division of the sciatic nerve at the midthigh. The graft length was 5 cm. Postoperatively the patient regained complete motor function of the tibial nerve, with partial return of sensation. Long-term follow-up with both MRI and ultrasound demonstrated nerve graft continuity and the absence of tumor formation at the repair site.

CONCLUSIONS

Presented here are the first 2 cases in which autologous SCs were used to supplement human peripheral nerve repair in long-segment injury. Both patients had significant improvement in both motor and sensory function with correlative imaging. This study demonstrates preliminary safety and efficacy of SC transplantation for peripheral nerve repair.

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Gabriella M. Paisan, Kenneth M. Crandall, Stephanie Chen, S. Shelby Burks, Laurence R. Sands, and Allan D. Levi

Anterior sacral meningoceles (ASMs) are rare lesions often associated with connective tissue disorders. These lesions are typically treated posteriorly via closure of the dural stalk. However, given their insidious nature, ASMs can be quite large on presentation, and this approach may not provide adequate decompression. In this case report, the authors describe the successful treatment of a large ASM through drainage and watertight closure of the cyst with an omental flap.

A 43-year-old woman with a history of Marfan syndrome and a large ASM was referred for neurosurgical intervention. The ASM was filling the pelvic cavity and causing severe compression of the bladder. The patient underwent surgical decompression of the cyst through an anterior transabdominal approach and closure of the fistulous tract with a pedicled omental flap. This is the first reported case of successful closure of an ASM with an omental flap. At the 6-month follow-up, the ASM had not recurred on imaging and the patient’s symptoms had resolved.

Anterior sacral meningoceles are rare lesions that often require neurosurgical intervention. Although most can be treated posteriorly, large ASMs compressing the abdominal or pelvic organs may require a transabdominal approach. Moreover, ASMs with wide dural stalks may benefit from closure with an omental flap.

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Victor M. Lu, S. Shelby Burks, Rainya N. Heath, Tizeta Wolde, Robert J. Spinner, and Allan D. Levi

OBJECTIVE

Meralgia paresthetica is caused by entrapment of the lateral femoral cutaneous nerve (LFCN) and often presents with pain. Multiple treatment options targeting the LFCN can be pursued to treat the pain should conservative measures fail, with the most common options being injection, neurolysis, and neurectomy. However, their efficacy in causing pain relief and their clinical outcomes have yet to be directly compared. The aim of this study was to interrogate the contemporary literature and quantitatively define how these options compare.

METHODS

The electronic databases Ovid Embase, PubMed, SCOPUS, and the Cochrane Library were interrogated from inception to May 2020 following the PRISMA guidelines. Candidate articles were screened against prespecified criteria. Outcome data were abstracted and pooled by random-effects meta-analysis of proportions.

RESULTS

There were 25 articles that satisfied all criteria, reporting outcomes for a total of 670 meralgia paresthetica patients, with 78 (12%) treated by injection, 496 (74%) by neurolysis, and 96 (14%) by neurectomy. The incidence of complete pain relief was 85% (95% CI 71%–96%) after neurectomy, 63% (95% CI 56%–71%) after neurolysis, and 22% (95% CI 13%–33%) after injection, which were all statistically different (p < 0.01). The incidence of revision procedures was 12% (95% CI 4%–22%) after neurolysis and 0% (95% CI 0%–2%) after neurectomy, which were significantly lower than 81% (95% CI 64%–94%) after injection (p < 0.01). The incidences of treatment complications were statistically comparable across all three treatments, ranging from 0% to 5% (p = 0.34).

CONCLUSIONS

There are multiple treatment options to target pain in meralgia paresthetica. The incidence of complete pain relief appears to be the greatest among the 3 interventions after neurectomy, accompanied by the lowest incidence of revision procedures. These findings should help inform patient preference and expectations. Greater exploration of the anatomical rationale for incomplete pain relief after surgical intervention will assist in optimizing further surgical treatment for meralgia paresthetica.

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G. Damian Brusko, Roberto J. Perez-Roman, Harold Tapamo, S. Shelby Burks, Aldo N. Serafini, and Michael Y. Wang

OBJECTIVE

Hybrid SPECT with CT imaging has been used to help elucidate pain generators in patients with axial neck and back pain, identifying potential sites for treatment. Few studies have examined its role in spine surgery and most literature focuses on its use postoperatively. The authors describe the largest series to date of patients with symptomatic spondylosis who underwent preoperative SPECT imaging for surgical planning.

METHODS

A retrospective medical and imaging record review was conducted to identify patients who underwent SPECT or SPECT/CT studies between January 2014 and May 2018. Patients who underwent spine surgical intervention for spondylosis with primary symptoms of axial neck or back pain and who had evidence of hypermetabolic foci on spinal SPECT imaging were included. Only those patients who subsequently underwent surgery on a spinal level associated with increased radiotracer uptake were included in the analysis. Patient baseline and demographic information, and data pertaining to SPECT imaging, surgical planning, and postoperative care were collected and analyzed.

RESULTS

A total of 23 patients with an average age at surgery of 60.0 ± 11.0 years were included. Fifteen patients (65.2%) were male. A total of 53 spinal levels were treated, with an average of 2.30 levels treated per patient. All patients underwent fusion surgery, either lumbar (n = 14), with interbody fusion most commonly used (64.2%); or cervical (n = 9), with anterior cervical discectomy and fusion (66.6%) being the most common. The average length of hospital stay was 3.45 ± 2.32 days. One patient developed a wound infection postoperatively, requiring readmission. At the 3-month follow-up, 18 patients (78.3%) reported clinical improvement in pain. Eleven patients (47.8%) reported complete symptom resolution at the 6-month follow-up. At 1 year postoperatively, 19 patients (82.6%) reported significant relief of their symptoms following surgery.

CONCLUSIONS

This is the largest series to date describing patients with axial neck and back pain who underwent preoperative SPECT imaging and subsequent surgical intervention on the affected spinal levels. The results demonstrate that SPECT imaging may be a useful adjunct to guide surgical planning, resulting in substantial clinical improvement following surgery.

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S. Shelby Burks, Anthony Diaz, Agnes E. Haggerty, Natalia de la Oliva, Rajiv Midha, and Allan D. Levi

OBJECTIVE

The current clinical standard of harvesting a nerve autograft for repair of long-segment peripheral nerve injuries (PNIs) is associated with many potential complications. Guidance channels offer an alternative therapy. The authors investigate whether autologous Schwann cells (SCs) implanted within a novel collagen-glycosaminoglycan conduit will improve axonal regeneration in a long-segment PNI model.

METHODS

Novel NeuraGen 3D collagen matrix conduits were implanted with autologous SCs to investigate axonal regeneration across a critical size defect (13 mm) in male Fischer rat sciatic nerve. Reversed sciatic nerve autografts served as positive controls, and conduits filled with serum only as negative controls. Electrophysiological assessments were made in vivo. Animals were killed at 4 or 16 weeks postinjury, muscle weights were measured, and grafts underwent immunohistochemical and morphometric analysis.

RESULTS

SC survival was confirmed by the presence of green fluorescent protein–labeled SCs within regenerated fibers. Regeneration and elongation of myelinated axons in all segments of the graft were significantly enhanced at 16 weeks in the SC-filled conduits compared to the conduit alone and were statistically similar to those of the autograft. Nerves repaired with SC-filled conduits exhibited onset latencies and nerve conduction amplitudes similar to those of the contralateral controls and autograft (p < 0.05). Adding SCs to the conduit also significantly reduced muscle atrophy compared to conduit alone (p < 0.0001).

CONCLUSIONS

Repair of long-segment PNI of rat sciatic nerve is significantly enhanced by SC-filled NeuraGen 3D conduits. Improvements in the total number of myelinated axons, axon diameter, and myelin thickness throughout SC-filled conduits allow for significant recovery in nerve conduction and a decrease in muscle atrophy.