Obturator to Femoral Nerve Transfer: 2-Dimensional Operative Video.

Injury to the femoral nerve can cause femoral nerve palsy,1 resulting in severe ambulation difficulties and loss of sensory function in the anteromedial thigh and medial calf.2,3 Treatment options focus on nerve repair by direct coaptation, nerve grafting, or nerve transfer.3 If the proximal nerve stump is inaccessible, the location of nerve injury is at a distance from the site of muscle innervation, and/or there is a large nerve gap, nerve transfer may be a promising alternative treatment option.4-6 Nerve transfer uses only one coaptation site and allows for a faster recovery time due to a shorter nerve regeneration distance.2,3 A 32-year-old woman presented with persistent and severe proximal right lower extremity weakness after a right retroperitoneal femoral nerve schwannoma resection at an outside institution. After surgery, she reported that she could not flex her right hip or extend her right knee. MRI demonstrated a right femoral nerve gap defect (7.5 cm) at the schwannoma resection site. A right obturator to femoral nerve transfer was performed (see Video). 1.5-year follow-up visit showed that she had begun to have evidence of active recruitment of the right quadriceps muscle and started walking without a knee brace. 2.5-year follow-up visit showed improving strength (4-) in her right quadriceps muscle, independent walking for longer distances, and participation in sporting activities. The patient consented to the procedure, and the patients and any identifiable individuals consented to publication of his/her image. Institutional Review Board approval was not required for this single case observational surgical video.

Risk factors for vascular injuries in anterior lumbar interbody fusion: a single-institution retrospective study.

OBJECTIVE: Vascular injuries in anterior lumbar interbody fusion (ALIF) occur due to the vascular manipulation needed to achieve optimal disc space exposure. In this study, the authors aimed to evaluate intraoperative vascular injuries in patients undergoing single- and multilevel ALIF at a large tertiary academic center. METHODS: Prospectively collected data specifically addressing postoperative complications in patients who underwent ALIF by neurosurgery spine faculty working with a specialized vascular surgeon were retrospectively reviewed. Demographic characteristics and intraoperative data were collected. Patients were split into vascular injury and non-vascular injury groups. Outcome comparisons were conducted using the chi-square exact and Wilcoxon rank-sum tests for categorical and continuous data, respectively. Logistic regression was used to investigate associations with vascular injury, with univariate analysis first conducted to identify candidate associations. Based on these results, variables demonstrating a between-groups test statistic of p < 0.10 were included in the multivariate analysis to determine the independent predictors of vascular injuries. RESULTS: In total, 323 patients who underwent ALIF procedures were identified: 51% were male (n = 166) and 49% were female (n = 157). The mean age was 57.1 years, with 56% (n = 182) having undergone prior lumbar surgery. Vascular injuries were encountered intraoperatively in 7.1% (n = 23) of patients, and the majority (91% [n = 21]) involved the left common iliac vein. Patients with vascular injuries were statistically older (mean 63.6 vs 56.6 years), had greater incidence rates of coronary artery disease, opioid use, multilevel ALIF surgery involving the L2-3 level, and surgery involving multiple disc spaces, had more multilevel anterior instrumentation, and experienced greater blood loss during surgery and longer length of stay (all p < 0.05). Overall, there was 1 death (0.3%) secondary to aortic artery injury. Multivariate analysis identified opioid use, multilevel ALIF involving L2-3, and multiple interbodies as statistically independent predictors of vascular injury (all p < 0.05). CONCLUSIONS: Identifying patient risk factors can reduce the risk of vascular injuries in ALIF. Opioid use, multilevel ALIF involving L2-3, and multiple interbodies were independent predictors of vascular injuries in ALIF.

Ventro-Lateral Meningioma of the Cervico-Thoracic Junction: 2-Dimensional Operative Video.

Meningiomas are one of the most common intradural extramedullary tumors.1 Symptoms often arise from cord compression, with gross total resection leading to the most optimal patient outcomes.2,3 Utilization of intraoperative neurophysiological monitoring can increase patient safety through real-time assessment of neural structures and reduce postoperative neurologic complications.4 In this video, we describe the operative techniques for the resection of a meningioma located at the cervico-thoracic junction. A 43-year-old female patient presented with 6 months of bilateral leg numbness and gait disturbances. MRI of the cervical spine demonstrated a cervical thoracic ventral meningioma causing severe cord compression from the bottom of the C6 lamina to the top of the T1 lamina. Surgical resection with intraoperative neuromonitoring with somatosensory-evoked potentials, motor-evoked potentials, and free-running electromyography was recommended. A partial C6-T1 laminectomy was routinely performed, and the dura was opened using a paramedian approach to allow for maximal tumor visualization. The tumor was carefully dissected and debulked, achieving gross total resection. Postoperatively, the patient experienced improvements in preoperative symptoms with no perioperative complications, and the final pathology confirmed the intradural lesion was a meningioma. This video illustrates the surgical technique and management of a spinal meningioma at the cervico-thoracic junction. Patient consent was obtained for their participation in this surgical video.

Exploration of the right peroneal nerve after a gunshot wound.

Background: Gunshot wounds (GSWs) often result in neuropraxia or a mixed injury pattern rather than direct nerve transection. There is still debate between early and delayed intervention for the optimal treatment of intact nerves following GSWs. Early intervention may prevent the formation of dense scar tissue, and delayed intervention allows for the zone of injury to be fully demarcated for optimal treatment planning. Here, we present the case of a 29-year-old male who underwent exploration of the right common peroneal nerve after a GSW. Case Description: A 29-year-old male presented for evaluation of a GSW to the right lower extremity at the level of the fibular head he sustained 2 months prior. Following his injury, he was immediately evaluated in the emergency department and offered supportive care. He reported paresthesias in the right lower extremity and a right-sided foot drop. Computed tomography demonstrated a bullet fragment in the distal right lower extremity, and ultrasound revealed a partial thickness injury in the right peroneal nerve. Exploration of the right common peroneal nerve and bullet fragment was recommended. The bullet fragment was removed from the distal right lower extremity in one piece. Following this, the right common peroneal nerve was decompressed proximally to distally, with scar tissue encountered distally. Postoperatively, the patient did well, ambulating shortly after surgery, and at 3 weeks postoperative, he was ambulating without difficulty. Conclusion: Clinical judgment and risk-benefit analysis of each patient must be made individually to determine the most optimal treatment method following GSWs.

Influence of instrumentation type on outcomes after surgical management of spondylodiscitis: a systematic review and meta-analysis.

OBJECTIVE: Spondylodiscitis refers to infection of the intervertebral disk and neighboring structures. Outcomes based on instrumentation type are not well reported in the literature, but are important in establishing guidelines for surgical management of spondylodiscitis. This study aims to clarify the effect of instrumentation material selection on clinical and radiographic outcomes in patients with spondylodiscitis. METHODS: Studies that evaluated the use of polyetheretherketone (PEEK), titanium, allograft, and/or autologous bone grafts for spondylodiscitis were identified in the literature. Radiographic and clinical data were analyzed using a meta-analysis of proportions, with estimated risk and confidence intervals reported for our primary study outcomes. RESULTS: Thirty-two retrospective studies totaling 1088 patients undergoing surgical management of spondylodiscitis with PEEK, TTN, allograft, and autologous bone graft instrumentation were included. There were no differences in fusion rates (p-interaction = 0.55) with rates of fusion of 93.4% with TTN, 98.6% with allograft, 84.2% with autologous bone graft, and 93.9% with PEEK. There were no differences in screw loosening (p-interaction = 0.52) with rates of 0.33% with TTN, 0% with allograft, 1.3% with autologous bone graft, and 8.2% with PEEK. There were no differences in reoperation (p-interaction = 0.59) with rates of 2.64% with TTN, 0% with allograft, 1.69% with autologous bone graft, and 3.3% with PEEK. CONCLUSIONS: This meta-analysis demonstrates that the choice of instrumentation type in the surgical management of spondylodiscitis resulted in no significant differences in rate of radiographic fusion, screw loosening, or reoperation. Future comparative studies to optimize guidelines for the management of spondylodiscitis are needed.

Resection of a lumbar intradural tumor.

Background: Myxopapillary ependymomas and schwannomas represent the most common tumors of the conus medullaris and cauda equina. Here, we present the surgical resection of a 64-year-old male with a lumbar intradural tumor. Case Description: A 64-year-old male presented with several months of the lower extremity weakness, pain, and bowel/bladder dysfunction. Magnetic resonance imaging demonstrated a large L3-5 intradural lesion, and surgical resection using intraoperative neuromonitoring with somatosensory evoked potentials (SSEPs), motor evoked potentials (MEPs), free-running electromygraphy (EMGs), and direct sphincter monitoring was recommended. After an L2-S1 laminectomy was performed, intraoperative ultrasound was used to confirm the cranial and caudal extent of the tumor. The dural was opened using a midline approach, and the tumor was quickly visualized. Through careful dissection, the tumor was debulked and gross total resection was ultimately achieved through a piecemeal resection. Hemostasis was frequently required throughout the case, as the tumor was highly vascular. Postoperatively, the patient was at his neurologic baseline and was discharged to rehab on postoperative day 4. The final pathology revealed the intradural lesion was a paraganglioma. Conclusion: Early intervention and gross total resection of spinal intradural tumors are associated with optimal patient outcomes. Additional adjuncts, such as ultrasound, are beneficial and can help achieve gross total tumor resection.

Intraoperative embolectomy of a left illiac artery thrombus during an anterior lumbar interbody fusion.

Background: Anterior lumbar interbody fusion (ALIF) offers direct midline access to the lumbar intervertebral discs utilizing an anterior retroperitoneal approach. Here, a 33-year-old female undergoing ALIF developed an acute intraoperative left iliac artery thrombus and underwent immediate successful embolectomy. Case Description: A 33-year-old female was undergoing routine L5-S1 ALIF when an acute intraoperative left iliac vein injury occurred, requiring immediate repair by a vascular surgeon. Her left foot pulse oximeter showed a decreased reading, and her Doppler ultrasound confirmed reduced flow in the distal external iliac artery due to a thrombus. She required an immediate left iliac artery embolectomy, and flow was immediately restored. Postoperatively, she recovered well, and 3 months postoperatively, she remained neurologically intact without any further complications. Conclusion: Using pulse oximeters in patients undergoing ALIF surgery can aid in facilitating the diagnosis and treatment of acute artery thrombi. When such vascular injuries arise, having immediate access to experienced vascular surgeons is critical to obtain expeditious treatment and optimize patient outcomes.

Surgical resection of an intradural extramedullary spinal tumor.

Large ventrally located spinal meningiomas are typically resected via a posterolateral or lateral approach. Optimal outcomes are associated with good preoperative functional status (i.e., modified McCormick grade < 4), while recurrence rates may be predicted by degree and quality of resection (i.e., low Simpson grade). This video describes the operative techniques for resection of a large ventral C2 intradural extramedullary meningioma in a 71-year-old male presenting with hemibody sensory loss and abnormal gait. A paramedian approach was performed, allowing for adequate exposure and gross-total resection. The patient was discharged on postoperative day 2 and showed near-complete resolution of sensory deficits.

Lower extremity peripheral nerve pathology: Utility of preoperative ultrasound-guided needle localization before operative intervention.

Historically, the use of ultrasound (US) in the management of peripheral nervous system (PNS) pathology has been limited to diagnostic confirmation or guidance for interventional injections. This technical case series will demonstrate the utility and versatility of preoperative US-guided needle localization for the excision of lower extremity neuromas and other pathology of the PNS. Five patients with symptomatic lower extremity PNS tumors were retrospectively reviewed. This case series corroborates the technical nuances of localizing lower extremity neuromas by US-guided needle and wire placement prior to operative excision. This was achieved by a multidisciplinary team that included plastic surgery, neurosurgery, and radiology. Five patients had US-guided needle localization of a lower extremity PNS target prior to operative intervention. Three patients had lower extremity neuromas of varying origins, including the lateral femoral cutaneous nerve (LFCN), saphenous nerve, and sural nerve. The remaining two patients had a sciatic nerve sheath Schwannoma and a femoral nerve glomus tumor. Under sonographic visualization, a needle was advanced to the target perimeter and withdrawn, leaving behind a percutaneous guidewire. This technique simplified the marking of the nerve course prior to dissection and led to efficient intraoperative identification of all five PNS tumors without any complications. Preoperative US-guided needle localization led to safe, accurate, and efficient perioperative and intraoperative identification of neuromas and other PNS tumors of the lower extremity prior to excision. By reducing the challenges of nerve identification in a scarred tissue bed, this multidisciplinary approach may decrease postoperative patient morbidity.

Surgical Management of Lumbosacral Plexus Tumors.

BACKGROUND: Lumbosacral plexus tumors are uncommon, and because of their deep location and proximity to critical nerves subserving lower extremity function, understanding surgical approaches and short-term outcomes is important. METHODS: In a retrospective case series of lumbosacral plexus tumor surgeries performed from May 2000 to July 2021 by a single neurosurgeon, demographic information, clinical presentation, imaging studies, and operative outcomes were analyzed. RESULTS: A total of 42 patients with mean age of 48.3 years (range, 16-84 years) underwent surgery for a lumbosacral plexus tumor. Patients presented with leg pain (n = 25; 59.5%), followed by back/flank pain (n = 5; 11.9%), abdominal/pelvic pain (n = 5; 11.9%), leg weakness (n = 5; 11.9%), and leg numbness (n = 3; 7.1%). The most common tumor pathology was schwannoma (n = 20; 50.0%) followed by neurofibroma (n = 9; 22.5%). A retroperitoneal approach was used in all cases. Gross total resection was achieved in 23 (54.8%) patients, and only 1 (2.4%) patient exhibited symptomatic tumor recurrence after subtotal resection of a malignant tumor. Mean follow-up was 33.1 months (range, 1-96 months). Postoperatively, patient neurological status remained unchanged or improved (n = 37; 88.1%). Complications were infrequent, with 4 (9.5%) patients experiencing new sensory symptoms and 1 patient (2.4%) experiencing new anticipated motor weakness after en bloc resection of a malignant tumor. CONCLUSIONS: Indications for surgery include pain and/or neurological symptoms attributable to the lesion or large size if asymptomatic. Careful study of preoperative imaging is necessary to determine the best approach. Intraoperative nerve stimulation is essential to preserve function and guide extent of resection in benign tumors.

Optimal Technique for Introducing Schwann Cells Into Peripheral Nerve Repair Sites.

Peripheral nerve injury (PNI) is found in a relatively large portion of trauma patients. If the injury is severe, such as with the presence of a long segmental gap, PNI can present a challenge for treatment. The current clinical standard of nerve harvest for the repair of long segmental gap PNI can lead to many potential complications. While other methods have been utilized, recent evidence indicates the relevance of cell therapies, particularly through the use of Schwann cells, for the treatment of PNI. Schwann cells (SCs) are integral in the regeneration and restoration of function following PNI. SCs are able to dedifferentiate and proliferate, remove myelin and axonal debris, and are supportive in axonal regeneration. Our laboratory has demonstrated that SCs are effective in the treatment of severe PNI when axon guidance channels are utilized. However, in order for this treatment to be effective, optimal techniques for cellular placement must be used. Thus, here we provide relevant background information, preclinical, and clinical evidence for our method in the treatment of severe PNI through the use of SCs and axon guidance channels.

Scalable culture techniques to generate large numbers of purified human Schwann cells for clinical trials in human spinal cord and peripheral nerve injuries.

OBJECTIVE: Schwann cells (SCs) have been shown to play an essential role in axon regeneration in both peripheral nerve injuries (PNIs) and spinal cord injuries (SCIs). The transplantation of SCs as an adjunctive therapy is currently under investigation in human clinical trials due to their regenerative capacity. Therefore, a reliable method for procuring large quantities of SCs from peripheral nerves is necessary. This paper presents a well-developed, validated, and optimized manufacturing protocol for clinical-grade SCs that are compliant with Current Good Manufacturing Practices (CGMPs). METHODS: The authors evaluated the SC culture manufacturing data from 18 clinical trial participants who were recruited for autologous SC transplantation due to subacute SCI (n = 7), chronic SCI (n = 8), or PNIs (n = 3). To initiate autologous SC cultures, a mean nerve length of 11.8 ± 3.7 cm was harvested either from the sural nerve alone (n = 17) or with the sciatic nerve (n = 1). The nerves were digested with enzymes and SCs were isolated and further expanded in multiple passages to meet the dose requirements for transplantation. RESULTS: An average yield of 87.2 ± 89.2 million cells at P2 and 150.9 ± 129.9 million cells at P3 with high viability and purity was produced. Cell counts and rates of expansion increased with each subsequent passage from P0 to P3, with the largest rate of expansion between P2 and P3. Larger harvest nerve lengths correlated significantly with greater yields at P0 and P1 (p < 0.05). In addition, a viability and purity above 90% was sustained throughout all passages in nearly all cell products. CONCLUSIONS: This study presents reliable CGMP-compliant manufacturing methods for autologous SC products that are suitable for regenerative treatment of patients with SCI, PNI, or other conditions.

Microsurgical Treatment of a Petrotentorial Dural Arteriovenous Fistula: The Vein, the Whole Vein, and Nothing but the Vein: 2-Dimensional Operative Video.

Dural arteriovenous fistulas (dAVFs) consist of abnormal anastomoses between 1 or multiple meningeal arteries to meningeal veins, venous sinuses, or subarachnoid veins.1 dAVFs account for 10% to 15% of all intracranial arteriovenous lesions.2 dAVFs can be challenging to treat with various approaches that include microsurgical ligation, endovascular embolization (transarterial or transvenous), and stereotactic radiosurgery. All these treatments share the common goal of disconnecting the draining vein from the fistulous point. We present a case of a 43-yr-old male who presented with progressive headaches and was found to have an incidental Zipfel type 3A3 right petrotentorial dAVF on catheter angiography. The patient underwent a right retrosigmoid craniotomy and clipping of 2 separate venous outflows. The case illustrates the principle that multiple venous outflows can exist in dAVF and a thorough analysis of the venous phase of the angiogram as well as corresponding inspection of the fistula at the time of surgical exploration is a necessity to avoid partial obliteration. The patient remained neurologically intact postoperatively and had complete resolution of his fistula on postoperative angiography. We review the neuroimaging, operative video, and technical nuances and provide a short literature review on the topic.4 The patient gave informed consent for the procedure and verbal consent for this publication. The patient consented to the publication of their image.

Antiresorptive and anabolic medications used in the perioperative period of patients with osteoporosis undergoing spine surgery: their impact on the biology of fusion and systematic review of the literature.

OBJECTIVE: Osteoporosis represents the most common metabolic disease of the bone, with an estimated 10% of adults aged 50 years or older affected in the United States. This patient population is at increased risk for spine fracture and instrumentation-related complications after spine surgery. Surgeon knowledge of the available treatments for patients with low bone mineral density (BMD) and how they impact biology of fusion may help mitigate negative effects in the postoperative period. Recombinant parathyroid hormone, which is sold under the name teriparatide, is the most extensively studied bone-protecting agent in humans. Additionally, the success of the monoclonal antibody denosumab has led to further clinical investigations of human patients undergoing spine surgery. Another monoclonal antibody, romosozumab, was recently approved by the US FDA for human use in patients with osteoporosis. Although studies of romosozumab in patients undergoing spine surgery have not been conducted, this is a promising potential therapeutic agent based on its early success in preclinical and clinical trials. Here, the authors aimed to review the mechanisms of action and evidence of use of antiresorptive and anabolic agents in patients with osteoporosis undergoing spine surgery. METHODS: In accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, a systematic review was conducted to explore the antiresorptive and anabolic agents used in the perioperative period in patients with osteoporosis undergoing spinal surgery. The search was performed by using the PubMed, Embase, and Cochrane Library databases. Titles and abstracts were screened and subsequently selected for full review. RESULTS: The initial search returned 330 articles. Of these articles, 23 final articles were included and reviewed. Many of these articles reported that use of adjuvant agents in the perioperative period improved radiographic evidence of bony fusion and bone fusion rates. These agents tended to improve BMD postoperatively. CONCLUSIONS: Although antiosteoporosis agents are effective to varying degrees as treatments of patients with low BMD, teriparatide and bisphosphonates have been the most extensively studied with respect to spinal instrumentation. The advent of newer agents represents an area for further exploration, especially due to the current paucity of controlled investigations. It is imperative for spine surgeons to understand the mechanisms of action of these drugs and their effects on biology of fusion.

Osteoporosis treatment in patients undergoing spinal fusion: a systematic review and meta-analysis.

OBJECTIVE: Bisphosphonates and teriparatide are the most common therapies used in the treatment of osteoporosis. Their impact on fusion rates in osteoporotic patients following spinal fusion has yet to be concretely defined, with previous systematic reviews focusing heavily on bisphosphonates and lacking clinical insight on the utility of teriparatide. Herein the authors present an updated meta-analysis of the utility of both bisphosphonates and teriparatide in improving spinal fusion outcomes in osteoporotic patients. METHODS: After a comprehensive search of the English-language literature in the PubMed and Embase databases, 11 clinical studies were included in the final qualitative and quantitative analyses. Of these studies, 9 investigated bisphosphonates, 7 investigated teriparatide, and 1 investigated a combination of teriparatide and denosumab. Odds ratios and 95% confidence intervals were calculated where appropriate. RESULTS: A meta-analysis of the postoperative use of bisphosphonate demonstrated better odds of successful fusion as compared to that in controls during short-term monitoring (OR 3.33, 95% CI 1.72-6.42, p = 0.0003) but not long-term monitoring (p > 0.05). Bisphosphonate use was also shown to significantly reduce the likelihood of postoperative vertebral compression fracture (VCF; OR 0.07, 95% CI 0.01-0.59, p = 0.01) and significantly reduce Oswestry Disability Index scores (mean difference [MD] = -2.19, 95% CI -2.94 to -1.44, p < 0.00001) and visual analog scale pain scores (MD = -0.58, 95% CI -0.79 to -0.38, p < 0.00001). Teriparatide was found to significantly increase fusion rates at long-term postoperative periods as compared to rates after bisphosphonate therapy, with patients who received postoperative teriparatide therapy 2.05 times more likely to experience successful fusion (OR 2.05, 95% CI 1.17-3.59, p = 0.01). CONCLUSIONS: The authors demonstrate the benefits of bisphosphonate and teriparatide therapy independently in accelerating fusion during the first 6 months after spinal fusion surgery in osteoporotic patients. In addition, they show that teriparatide may have superior benefits in spinal fusion during long-term monitoring as compared to those with bisphosphonates. Bisphosphonates may be better suited in preventing VCFs postoperatively in addition to minimizing postoperative disability and pain.