S. Shelby Burks

The Use of Autologous Schwann Cells to Supplement Sciatic Nerve Repair With a Large Gap: First in Human Experience.

Insufficient donor nerve graft material in peripheral nerve surgery remains an obstacle for successful long-distance regeneration. Schwann cells (SCs) can be isolated from adult mammalian peripheral nerve biopsies and can be grown in culture and retain their capacity to enhance peripheral nerve regeneration within tubular repair strategies in multiple animal models. Human Schwann cells (hSCs) can be isolated, expanded in number, and retain their ability to promote regeneration and myelinate axons, but have never been tested in a clinical case of peripheral nerve injury. A sural nerve biopsy and peripheral nerve tissue from the traumatized sciatic nerve stumps was obtained after Food and Drug Administration (FDA) and Institutional Review Board (IRB) approval as well as patient consent. The SCs were isolated after enzymatic digestion of the nerve and expanded with the use of heregulin β1 (0.1 μg/ml) and forskolin (15 mM). After two passages the Schwann cell isolates were combined with sural nerve grafts to repair a large sciatic nerve defect (7.5 cm) after a traumatic nerve injury. The sural nerve and the traumatized sciatic nerve ends both served as an excellent source of purified (90% and 97%, respectively) hSCs. Using ultrasound and magnetic resonance imaging (MRI) we were able to determine continuity of the nerve graft repair and the absence of tumor formation. The patient had evidence of proximal sensory recovery and definitive motor recovery distal to the repair in the distribution of the tibial and common peroneal nerve. The patient did experience an improvement in her pain scores over time. The goals of this approach were to determine the safety and clinical feasibility of implementing a new cellular repair strategy. In summary, this approach represents a novel strategy in the treatment of peripheral nerve injury and represents the first reported use of autologous cultured SCs after human peripheral nerve injury.

Challenges in sciatic nerve repair: anatomical considerations

UNLABELLED 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 mm(2), circumference 6.67 ± 1.60 mm, diameter 2.36 ± 0.43 mm, fat content 0.83 ± 0.91 mm(2), 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 mm(2), 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.

The utility of ultrasound in the assessment of traumatic peripheral nerve lesions: report of 4 cases

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.

First human experience with autologous Schwann cells to supplement sciatic nerve repair: report of 2 cases with long-term follow-up

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.

Scenario Planning: Playing the Expectations Game in Spine Surgery

Since the time of Hippocrates, accurate prognosis has been at the heart of medical practice. But as modern science equips physicians with tools of ever greater diagnostic and therapeutic power, authentic predictions of survival and quality-of-life have become paramount in selecting appropriate interventions for a variety of complex pathologies. Further, as medical ethics have evolved to place greater authority in the hands of patients, the ability to convincingly define what outcomes are achievable is key to educate patients who are making life-altering medical decisions. In a recent issue of the New England Journal of Medicine, Schwarze and Taylor present a case of trauma, malignancy, and uncertainty. In it, they illustrate a clinical application of scenario planning: an economic method for understanding and representing a nebulous future. Instead of quoting percentages and probabilities for discrete aspects of a clinical outcome, this approach describes a variety of integrated scenarios. Each possible scenario can then be ranked by likelihood and desirability. In this way, physicians can help patients better visualize and understand the impact of each clinical decision. The principles of scenario planning are highly applicable to the field of spinal neurosurgery. Our patients frequently have multiple medical comorbidities, chronic intractable pain, and a psychologic desperation born of the long course that led them to our clinics. For these reasons, many may have unrealistic expectations for what surgery can offer. In such cases, preoperative education may prove as important to outcomes as the surgery itself.

Volumetry in the Assessment of Pituitary Adenoma Resection: Endoscopy versus Microscopy

Abstract Background Assessment of the extent of resection after surgical resection of pituitary adenomas is most commonly reported in terms of the presence or absence of residual tumor. A quantitative comparison of volumetric resection between endonasal endoscopy (EE) and microsurgery (MS) has rarely been done. Methods A retrospective analysis was performed on a consecutive series of 154 patients with pituitary adenomas treated by the same surgeon at a single institution. We employed volumetric analysis pre‐ and postoperatively on two cohorts of pituitary adenoma patients treated through MS (n = 37) versus EE approach (n = 117). Results Volumetric analysis revealed a higher incidence of complete resection (64.4 vs. 56.8%) and mean volume reduction in the EE cohort (92.7 vs. 88.4%), although not significant. Recurrence rates were significantly lower in the EE group (7.7% vs 24.3%, p = 0.015). Subgroup analysis identified that patients with preoperative tumor volumes >1 mL were less likely to recur through EE (7.8 vs. MS: 29.6%; p = 0.0063). A higher incidence of complete resection was also noted in patients with favorable Knosp grades (0‐1) (EE: 87.8 vs. MS: 63.2%; p = 0.036). Postoperative complication rates were not significantly different between both techniques. Conclusion Both microscopy and endoscopy are well‐tolerated, effective approaches in the treatment of pituitary adenomas. Our series demonstrated that EE may be superior to MS in preventing tumor recurrence and achieving a complete resection in certain subsets of patients. EE provides a slight advantage in tumor control outcomes that may justify the paradigm shift to pure endoscopy at our center.

Fracture of fusion mass following anterior cervical plate removal: Case report

We present the case of a delayed pseudoarthrosis resulting from a fracture at the site of a radiographically confirmed anterior cervical fusion following plate removal. In this case, an anterior cervical plate was removed to allow for further surgery at a supra-adjacent level. A modicum of literature exists describing delayed fractures following hardware removal in thoracolumbar fusion constructs. The development of a fracture/pseudoarthrosis following hardware removal at the site of a radiographically confirmed anterior cervical fusion has not been previously reported. We describe the clinical presentation and operative management in the case of this rare and unexpected complication.

Spontaneous healing of a shredded esophagus after ACDF without direct repair

Esophageal perforation is a catastrophic complication of anterior cervical discectomy and fusion (ACDF). While direct surgical repair has been reported as optimal for restoration of upper gut function, we present the case of a 58-year-old woman who achieved complete resolution when treated only with debridement and drainage. We find that a supportive approach, surgical management without direct repair, may play a vital role in select patient populations in order to avoid potentially long-term consequences or radical treatments, like esophageal diversion. Decisions regarding direct repair versus debridement and inspection only should be made on a case-by-case basis through a multidisciplinary approach.

Intraoperative imaging in traumatic peripheral nerve lesions: Correlating histologic cross-sections with high-resolution ultrasound

BACKGROUND Intraoperative ultrasound (US) has been used as a guide during surgery to better identify deep neuroanatomical structures. OBJECTIVE To correlate histologic cross-sections from nerve samples taken at the time of surgery with axial, high-resolution US images at similar locations and validate this important tool for intraoperative guidance in nerve surgery. METHODS Three subjects undergoing nerve repair procedures after traumatic nerve injuries were enrolled prospectively. US images captured at the time of surgery were later matched with gross anatomic cross-sections and fascicular anatomy compared across modalities. RESULTS In cases 1 and 3, neuromatous tissue spanned the entire cross-section of the common peroneal and upper trunk of the brachial plexus, respectively. In case 2, only a portion of the sciatic nerve was involved with neuroma. Intraoperative US aided in differentiating normal peripheral nerve from neuroma in all 3 cases and helped minimize the disruption of healthy peripheral nerve tissue. CONCLUSION Intraoperative US correlates well with anatomic sections removed at the time of surgery. The ability to noninvasively image the peripheral nerve along with compound nerve action potentials can greatly assist in determining the extent of neurolysis, resection, and grafting and is a useful adjunct for intraoperative decision-making. This report serves to highlight the role of US and validate its use in peripheral nerve surgery for trauma.

Multiple recurrent postoperative spinal infections due to an unrecognized presacral abscess following placement of bicortical sacral screws: case report.

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.