The secondary injury cascade after spinal cord injury: an analysis of local cytokine/chemokine regulation

JOURNAL/nrgr/04.03/01300535-202406000-00035/inline-graphic1/v/2023-10-30T152229Z/r/image-tiff

After spinal cord injury, there is an extensive infiltration of immune cells, which exacerbates the injury and leads to further neural degeneration. Therefore, a major aim of current research involves targeting the immune response as a treatment for spinal cord injury. Although much research has been performed analyzing the complex inflammatory process following spinal cord injury, there remain major discrepancies within previous literature regarding the timeline of local cytokine regulation. The objectives of this study were to establish an overview of the timeline of cytokine regulation for 2 weeks after spinal cord injury, identify sexual dimorphisms in terms of cytokine levels, and determine local cytokines that significantly change based on the severity of spinal cord injury. Rats were inflicted with either a mild contusion, moderate contusion, severe contusion, or complete transection, 7 mm of spinal cord centered on the injury was harvested at varying times post-injury, and tissue homogenates were analyzed with a Cytokine/Chemokine 27-Plex assay. Results demonstrated pro-inflammatory cytokines including tumor necrosis factor α, interleukin-1β, and interleukin-6 were all upregulated after spinal cord injury, but returned to uninjured levels within approximately 24 hours post-injury, while chemokines including monocyte chemoattractant protein-1 remained upregulated for days post-injury. In contrast, several anti-inflammatory cytokines and growth factors including interleukin-10 and vascular endothelial growth factor were downregulated by 7 days post-injury. After spinal cord injury, tissue inhibitor of metalloproteinase-1, which specifically affects astrocytes involved in glial scar development, increased more than all other cytokines tested, reaching 26.9-fold higher than uninjured rats. After a mild injury, 11 cytokines demonstrated sexual dimorphisms; however, after a severe contusion only leptin levels were different between female and male rats. In conclusion, pro-inflammatory cytokines initiate the inflammatory process and return to baseline within hours post-injury, chemokines continue to recruit immune cells for days post-injury, while anti-inflammatory cytokines are downregulated by a week post-injury, and sexual dimorphisms observed after mild injury subsided with more severe injuries. Results from this work define critical chemokines that influence immune cell infiltration and important cytokines involved in glial scar development after spinal cord injury, which are essential for researchers developing treatments targeting secondary damage after spinal cord injury.

Anatomical Relationships of the Sciatic Nerve and Pudendal Nerve to the Ischial Spine as They Exit the Greater Sciatic Foramen

OBJECTIVE

Deep gluteal syndrome is a clinical condition in which discomfort may arise due to the pathoanatomy of the subgluteal space. We conducted an anatomical exploration to categorize the relationship of the piriformis muscle, sciatic nerve (SN), and pudendal nerve (PN) to the ischial spine (IS) and sacrospinous ligament.

METHODS

We analyzed 22 cadavers. The piriformis muscle, SN, and PN were exposed through either a transgluteal approach or a gluteal flap. The relationship of the neural structures to the IS, sacrospinous ligament, and ischial bone as they exit the greater sciatic foramen was observed, and the exit zones were classified as zone A, medial to the IS (entirely on sacrospinous ligament); zone B, on the IS; and zone C, lateral to the IS (entirely on ischial bone).

RESULTS

The SN was observed either in zone B or zone C in all specimens. The PN was found to be in either zone A or zone B in 97.6% of specimens. The most common combinations were SN in zone B and PN in zone A (type I), and SN in zone C and PN in zone B (type II).

CONCLUSIONS

The results from this study show clear anatomical differences in the SN-PN relationship, which may play a role in pain seen in deep gluteal syndrome. Moreover, classification of the SN-IS and PN-IS relationships described in this article will help describe different pathologies affecting the deep gluteal area.

Gait analysis in swine, sheep, and goats after neurologic injury: a literature review

Medical research on neurologic ailments requires representative animal models to validate treatments before they are translated to human clinical trials. Rodents are the predominant animal model used in neurological research despite limited anatomic and physiologic similarities to humans. As a result, functional testing designed to assess locomotor recovery after neurologic impairment is well established in rodent models. Comparatively, larger, more clinically relevant models have not been as well studied. To achieve similar locomotor testing standardization in larger animals, the models must be accessible to a wide array of researchers. Non-human primates are the most relevant animal model for translational research, however ethical and financial barriers limit their accessibility. This review focuses on swine, sheep, and goats as large animal alternatives for transitional studies between rodents and non-human primates. The objective of this review is to compare motor testing and data collection methods used in swine, sheep, and goats to encourage testing standardization in these larger animal models. The PubMed database was analyzed by searching combinations of swine, sheep, and goats, neurologic injuries, and functional assessments. Findings were categorized by animal model, data collection method, and assessment design. Swine and sheep were used in the majority of the studies, while only two studies were found using goats. The functional assessments included open pen analysis, treadmill walking, and guided free walking. Data collection methods included subjective behavioral rating scales and objective tools such as pressure-sensitive mats and image-based analysis software. Overall, swine and sheep were well-suited for a variety of assessment designs, with treadmill walking and guided free walking offering the most consistency across multiple trials. Data collection methods varied, but image-based gait analysis software provided the most robust analysis. Future studies should be conducted to standardize functional testing methods after neurologic impairment in large animals.

Large vertebral artery pseudoaneurysm masquerading as a schwannoma: illustrative case

BACKGROUND

Extracranial vertebral aneurysms or pseudoaneurysms are rare and result primarily from trauma. Large pseudoaneurysms can masquerade as mass lesions, making it challenging to identify the correct diagnosis.

OBSERVATIONS

This is a case report in which a large vertebral pseudoaneurysm posed as a schwannoma and biopsy was attempted. It was later identified as a vascular lesion and treated appropriately with no complications.

LESSONS

Vascular etiologies should always be included in the differential diagnosis of spine and nerve pathologies especially lesions that are in the vicinity of major vascular channels such as the transverse foramina of the cervical spine.

A combined, supraclavicular, infraclavicular, transaxillary, and posterior subscapular approaches for en bloc resection of giant myxofibrosarcoma

Background

Myxofibrosarcoma (MFS) is a rare and locally infiltrative tumor that commonly occurs in extremities in older adults; however, truncal and head and neck cases have been reported. They are characterized by multinodular growth, incomplete fibrous septa, and myxoid stroma. Surgical resection is the mainstay of treatment.

Case Description

The authors report a case of a combined, supraclavicular, infraclavicular, transaxillary, and posterior subscapular approaches for resection of giant MFS.

Conclusion

The anatomical complexity and rarity of tumors involving the brachial plexus impose many challenges onto surgeons performing surgical resections. Treatment choices and surgical outcomes rely heavily on meticulous multidisciplinary planning, anatomical knowledge, careful dissection, and extent of resection. This case is unique in utilizing four different approaches to the brachial plexus to resect one tumor.

Peroneal Nerve Repair with Cross-Bridge Ladder Technique: Parallel End-to-Side Neurorrhaphies

Background  Multiple nerve transfer techniques are used to treat patients with nerve injuries when a primary repair is not possible. These techniques are categorized to end-to-end, end-to-side, and side-to-side neurorrhaphy. Our study aims to explore the utility of the cross-bridge ladder technique (H-shaped), which has shown promising results in animal models and probably underutilized clinically. Methods  Four patients with significant loss of ankle dorsiflexion were seen in the clinic and underwent evaluation, including electrodiagnostic studies. A cross-bridge ladder repair technique was used between the tibial nerve as the donor and the common peroneal nerve as the recipient via one or two nerve grafts coapted in parallel with end-to-side neurorrhaphies. Dorsiflexion strength was measured preoperatively using the Medical Research Council (MRC) grading system and at each postoperative follow-up appointment. Results  All four patients had suffered persistent and severe foot drop (MRC of 0) following trauma that had occurred between 6 and 15 months preoperatively. Three of the four patients improved to an MRC of 2 several months postoperatively. The last patient had an immediate improvement to an MRC of 2 by his first month and had a complete recovery of ankle dorsiflexion within 4 months from surgery. Conclusion  We demonstrate the utility and clinical outcomes of the cross-bridge ladder technique in patients with persistent and prolonged foot drop following trauma. Both early and late recovery were seen while all patients regained motor function, with some patients continuing to improve up to the most recent follow-up. IRB Approval: Obtained 2013-1411-CP005.

Lateral femoral cutaneous nerve transposition

Lateral femoral cutaneous neuropathy, also known as meralgia paresthetica, is a pathology commonly encountered by neurosurgeons. Symptoms include numbness, tingling, and burning pain over the anterolateral thigh due to impingement on the lateral femoral cutaneous nerve (LFCN). Surgical treatment has traditionally involved nerve release or neurectomy. LFCN transposition is a relatively new approach that can provide excellent symptomatic relief. In this video, the authors highlight key operative techniques to ensure easy identification, adequate decompression, and transposition of the nerve. Key steps include ultrasound-guided wire localization, superficial decompression, opening of the inguinal ligament, deep decompression, and medial transposition. The video can be found here: https://stream.cadmore.media/r10.3171/2022.10.FOCVID2289.

Supraclavius muscle observed during anterior scalenectomy for thoracic outlet syndrome: A report of two cases and review of the literature

Background

Thoracic outlet syndrome (TOS) is a clinical diagnosis caused by compression of neurovascular structures in the thoracic outlet. There are a variety of structures that cause compression implicated in TOS. TOS patients frequently require surgical decompression. Various structural anomalies encountered during decompression have been reported in the literature.

Case Description

We present two females (ages 42 and 45) that each underwent anterior scalenectomy for thoracic outlet decompression through a supraclavicular approach. A supraclavius muscle anomaly was observed in both patients. Analogous to the two reports previously described in the literature, the muscle inserted, along the medial superior undersurface of the clavicle and originated dorsally along the trapezius muscle. This is not to be confused with the subclavius posticus muscle, which originates from the first rib and inserts on the upper border of the scapula.

Conclusion

These two cases represent just the third and fourth ever descriptions of a supraclavius muscle anomaly encountered during TOS surgery. Due to the wide variety of anatomical variations encountered during TOS surgery, it is not only crucial for continued reporting of such anatomical variations to be reported in the literature but equally important for clinicians that treat TOS to be aware of such variations.

Outcomes following conservative treatment of extension fractures in the setting of diffuse idiopathic skeletal hyperostosis: is external orthosis alone a reasonable option?

OBJECTIVE

Extension fractures in the setting of diffuse idiopathic skeletal hyperostosis (DISH) represent highly unstable injuries. As a result, these fractures are most frequently treated with immediate surgical fixation to limit any potential risk of associated neurological injury. Although this represents the standard of care, patients with significant comorbidities, advanced age, or medical instability may not be surgical candidates. In this paper, the authors evaluated a series of patients with extension DISH fractures who were treated with orthosis alone and evaluated their outcomes.

METHODS

A retrospective review from 2015 to 2022 was conducted at a large level 1 trauma center. Patients with extension-type DISH fractures without neurological deficits were identified. All patients were treated conservatively with orthosis alone. Baseline patient characteristics and adverse outcomes are reported.

RESULTS

Twenty-seven patients were identified as presenting with extension fractures associated with DISH without neurological deficit. Of these, 22 patients had complete follow-up on final chart review. Of these 22 patients, 21 (95.5%) were treated successfully with external orthosis. One patient (4.5%) who was noncompliant with the brace had an acute spinal cord injury 1 month after presentation, requiring immediate surgical fixation and decompression. No other complications, including skin breakdown or pressure ulcers related to bracing, were reported.

CONCLUSIONS

Treatment of extension-type DISH fractures may be a reasonable option for patients who are not candidates for safe surgical intervention; however, a risk of neurological injury secondary to delayed instability remains, particularly if patients are noncompliant with the bracing regimen. This risk should be balanced against the high complication rate and potential mortality associated with surgical intervention in this patient population.

Benign eccrine spiradenoma imitating a nerve sheath tumor: illustrative case

BACKGROUND

Benign eccrine spiradenoma is a rare tumor arising from the sweat glands and is a pathology that is almost never encountered in routine neurosurgical practice. Although this is a rare pathology, it is one that should be included in the differential diagnosis for a patient presenting with a painful, subcutaneous mass, because it can guide further treatment considerations.

OBSERVATIONS

The authors present a case of benign eccrine spiradenoma that mimicked a nerve sheath tumor in clinical presentation, imaging characteristics, and gross appearance.

LESSONS

Complete local excision of these lesions is the gold standard treatment, because they are painful, and there are reports of local recurrence and malignant degeneration with incomplete resection. For this reason, neurosurgeons should be sure to include this in the differential diagnosis of a patient with a painful, subcutaneous mass, because it may help to guide management decisions.

Brachial plexus anatomy in the miniature swine as compared to human

Brachial plexus injury (BPI) occurs when the brachial plexus is compressed, stretched, or avulsed. Although rodents are commonly used to study BPI, these models poorly mimic human BPI due to the discrepancy in size. The objective of this study was to compare the brachial plexus between human and Wisconsin Miniature SwineTM (WMSTM ), which are approximately the weight of an average human (68-91 kg), to determine if swine would be a suitable model for studying BPI mechanisms and treatments. To analyze the gross anatomy, WMS brachial plexuses were dissected both anteriorly and posteriorly. For histological analysis, sections from various nerves of human and WMS brachial plexuses were fixed in 2.5% glutaraldehyde, and postfixed with 2% osmium tetroxide. Subsequently paraffin sections were counter-stained with Masson's Trichrome. Gross anatomy revealed that the separation into three trunks and three cords is significantly less developed in the swine than in human. In swine, it takes the form of upper, middle, and lower systems with ventral and dorsal components. Histological evaluation of selected nerves revealed differences in nerve trunk diameters and the number of myelinated axons in the two species. The WMS had significantly fewer myelinated axons than humans in median (p = 0.0049), ulnar (p = 0.0002), and musculocutaneous nerves (p = 0.0454). The higher number of myelinated axons in these nerves for humans is expected because there is a high demand of fine motor and sensory functions in the human hand. Due to the stronger shoulder girdle muscles in WMS, the WMS suprascapular and axillary nerves were larger than in human. Overall, the WMS brachial plexus is similar in size and origin to human making them a very good model to study BPI. Future studies analyzing the effects of BPI in WMS should be conducted.

Surgical decompression of an accessory bicipital aponeurosis associated with median neuropathy in the antecubital fossa: A case report

Background:

Accessory muscles in the arm are well-known anatomical variants which have been hypothesized as sources of neurovascular compression syndromes. We report a rare presentation of neuropathy secondary to an accessory biceps aponeurosis causing compression of the median nerve in the antecubital fossa.

Case Description:

A 65-year-old man presented with a 5-year history of numbness and pain associated with arm flexion. Electromyography was normal and exam revealed mild weakness in the median nerve distribution; however, magnetic resonance imaging demonstrated an accessory biceps tendon overlaying the median nerve in the antecubital fossa. The patient underwent surgical decompression of the median nerve with detachment of the accessory tendon resulting in clinical improvement.

Conclusion:

Anomalous biceps musculature should be considered in the workup and treatment of proximal median neuropathy.

Inflammation after spinal cord injury: a review of the critical timeline of signaling cues and cellular infiltration

Traumatic spinal cord injury (SCI) is a devastating neurological condition that results in a loss of motor and sensory function. Although extensive research to develop treatments for SCI has been performed, to date, none of these treatments have produced a meaningful amount of functional recovery after injury. The primary injury is caused by the initial trauma to the spinal cord and results in ischemia, oxidative damage, edema, and glutamate excitotoxicity. This process initiates a secondary injury cascade, which starts just a few hours post-injury and may continue for more than 6 months, leading to additional cell death and spinal cord damage. Inflammation after SCI is complex and driven by a diverse set of cells and signaling molecules. In this review, we utilize an extensive literature survey to develop the timeline of local immune cell and cytokine behavior after SCI in rodent models. We discuss the precise functional roles of several key cytokines and their effects on a variety of cell types involved in the secondary injury cascade. Furthermore, variations in the inflammatory response between rats and mice are highlighted. Since current SCI treatment options do not successfully initiate functional recovery or axonal regeneration, identifying the specific mechanisms attributed to secondary injury is critical. With a more thorough understanding of the complex SCI pathophysiology, effective therapeutic targets with realistic timelines for intervention may be established to successfully attenuate secondary damage.

The Window Test: a simple bedside method to detect radial deviation of the wrist commonly seen in posterior interosseous nerve palsy

BACKGROUND

Posterior interosseous nerve palsy (PINP) is a disorder caused by damage to the posterior interosseous nerve, resulting in weak extension of the wrist and fingers as well as radial deviation of the wrist.

METHODS

In this study, a new type of evaluation for PINP was analyzed in hopes of increasing ease of diagnosis and earlier detection of the disorder. The "Window Test" is performed by the examiner laying hands on the ulnar aspect of the patient's pronated forearm while the latter is trying to extend the wrist. A positive test is observed when a gap (window) appears between the examiner's forearm and the patient's hand. Lay people, medical students, residents, and practicing providers were assessed prospectively on their ability to correctly diagnose PINP by observing one hand, both hands, and by using the Window Test.

RESULTS

The Window Test was consistently found to be the most effective method of evaluation as it increased the accuracy of diagnoses in all groups surveyed. Additionally, case studies were performed using the Window Test on patients, further demonstrating the efficacy of the test by confirming wrist radial deviation.

CONCLUSION

The Window Test introduces a reference frame, making it easier to assess wrist radial deviation and offering a simple evaluation that can be administered by virtually anyone. These findings indicate that the implementation of the Window Test will increase the accuracy and effectiveness of PINP diagnosis, thus allowing early diagnosis and better management.

Functional recovery after peripheral nerve injury via sustained growth factor delivery from mineral-coated microparticles

The gold standard for treating peripheral nerve injuries that have large nerve gaps where the nerves cannot be directly sutured back together because it creates tension on the nerve, is to incorporate an autologous nerve graft. However, even with the incorporation of a nerve graft, generally patients only regain a small portion of function in limbs affected by the injury. Although, there has been some promising results using growth factors to induce more axon growth through the nerve graft, many of these previous therapies are limited in their ability to release growth factors in a sustained manner and tailor them to a desired time frame. The ideal drug delivery platform would deliver growth factors at therapeutic levels for enough time to grow axons the entire length of the nerve graft. We hypothesized that mineral coated microparticles (MCMs) would bind, stabilize and release biologically active glial cell-derived neurotrophic factor (GDNF) and nerve growth factor (NGF) in a sustained manner. Therefore, the objective of this study was to test the ability of MCMs releasing growth factors at the distal end of a 10 mm sciatic nerve graft, to induce axon growth through the nerve graft and restore hind limb function. After sciatic nerve grafting in Lewis rats, the hind limb function was tested weekly by measuring the angle of the ankle at toe lift-off while walking down a track. Twelve weeks after grafting, the grafts were harvested and myelinated axons were analyzed proximal to the graft, in the center of the graft, and distal to the graft. Under physiological conditions in vitro, the MCMs delivered a burst release of NGF and GDNF for 3 days followed by a sustained release for at least 22 days. In vivo, MCMs releasing NGF and GDNF at the distal end of sciatic nerve grafts resulted in significantly more myelinated axons extending distal to the graft when compared to rats that received nerve grafts without growth factor treatment. The rats with nerve grafts incorporated with MCMs releasing NGF and GDNF also showed significant improvement in hind limb function starting at 7 weeks postoperatively and continuing through 12 weeks postoperatively when compared to rats that received nerve grafts without growth factor treatment. In conclusion, MCMs released biologically active NGF and GDNF in a sustained manner, which significantly enhanced axon growth resulting in a significant improvement of hind limb function in rats. The animal experiments were approved by University of Wisconsin-Madison Animal Care and Use Committee (ACUC, protocol# M5958) on January 3, 2018.

Median Nerve Variation: A Complete Spin before Terminal Branching

Median nerve anatomy is of great interest to clinicians and scientists given the importance of this nerve and its association with diseases. A rare anatomical variant of the median nerve in the distal forearm and wrist was discovered during a cadaveric dissection. The median nerve was deep to the flexor digitorum superficialis (FDS) in the carpal tunnel. It underwent a 360-degree spin before emerging at the lateral edge of FDS. The recurrent motor branch moved from medial to lateral on the deep surface of the median nerve, as it approached the distal carpal tunnel. This variant doesn't fall into any of Lanz's four groups of median nerve anomalies. We propose a fifth group that involves variations in the course of the median nerve. This report underscores the importance of recognizing variants of the median nerve anatomy in the forearm and wrist during surgical interventions, such as for carpal tunnel syndrome.

Ultrasound-Guided Microwave Ablation for the Management of Inguinal Neuralgia: A Preliminary Study with 1-Year Follow-up

PURPOSE

To evaluate the feasibility and efficacy of ultrasound-guided microwave ablation for the treatment of inguinal neuralgia.

MATERIALS AND METHODS

A retrospective review of 12 consecutive ultrasound-guided microwave ablation procedures was performed of 10 consecutive patients (8 men, 2 women; mean age, 41 years [range, 15-64 years]), between August 2012 and August 2016. Inclusion criteria for inguinal neuralgia included clinical diagnosis of chronic inguinal pain (average, 17.3 months [range, 6-46 months]) refractory to conservative treatment and a positive nerve block. Pain response-reduction of pain level and duration and percent pain reduction using a 10-point visual analog scale (VAS) at baseline and up to 12 months after the procedure-was measured. Nine patients had pain after the inguinal hernia repair, and 1 patient had pain from the femoral artery bypass procedure. The microwave ablation procedure targeted the ilioinguinal nerve in 7 cases, the genitofemoral nerve in 4 cases, and the iliohypogastric nerve in 1 case.

RESULTS

Average baseline VAS pain score was 6.1 (standard deviation, 2.5). Improved pain levels immediately after the procedure and at 1, 6, and 12 months were statistically significant (P = .0037, .0037, .0038, .0058, respectively). Also, 91.7% (11/12) of the procedures resulted in immediate pain relief and at 1 month and 6 months. At 12 months, 83.3% (10/12) of patients had an average of 69% ± 31% pain reduction. Percent maximal pain reduction was 93% ± 14% (60%-100%), and the average duration of clinically significant pain reduction was 10.5 months (range, 0-12 months.). No complications or adverse outcomes occurred.

CONCLUSIONS

Ultrasound-guided microwave ablation is an effective technique for the treatment of inguinal neuralgia after herniorrhaphy.

Sustained interleukin-10 delivery reduces inflammation and improves motor function after spinal cord injury

Background

The anti-inflammatory cytokine interleukin-10 (IL-10) has been explored previously as a treatment method for spinal cord injury (SCI) due to its ability to attenuate pro-inflammatory cytokines and reduce apoptosis. Primary limitations when using systemic injections of IL-10 are that it is rapidly cleared from the injury site and that it does not cross the blood–spinal cord barrier.

Objective

Here, mineral-coated microparticles (MCMs) were used to obtain a local sustained delivery of IL-10 directly into the injury site after SCI.

Methods

Female Sprague-Dawley rats were contused at T10 and treated with either an intraperitoneal injection of IL-10, an intramedullary injection of IL-10, or MCMs bound with IL-10 (MCMs+IL-10). After treatment, cytokine levels were measured in the spinal cord, functional testing and electrophysiology were performed, axon tracers were injected into the brainstem and motor cortex, macrophage levels were counted using flow cytometry and immunohistochemistry, and lesion size was measured.

Results

When treated with MCMs+IL-10, IL-10 was significantly elevated in the injury site and inflammatory cytokines were significantly suppressed, prompting significantly less cells expressing antigens characteristic of inflammatory macrophages and significantly more cells expressing antigens characteristic of earlier stage anti-inflammatory macrophages. Significantly more axons were preserved within the rubrospinal and reticulospinal tracts through the injury site when treated with MCMs+IL-10; however, there was no significant difference in corticospinal tract axons preserved, regardless of treatment group. The rats treated with MCMs+IL-10 were the only group with a significantly higher functional score compared to injured controls 28 days post-contusion.

Conclusion

These data demonstrate that MCMs can effectively deliver biologically active IL-10 for an extended period of time altering macrophage phenotype and aiding in functional recovery after SCI.

Differences in neuroplasticity after spinal cord injury in varying animal models and humans

Rats have been the primary model to study the process and underlying mechanisms of recovery after spinal cord injury. Two weeks after a severe spinal cord contusion, rats can regain weight-bearing abilities without therapeutic interventions, as assessed by the Basso, Beattie and Bresnahan locomotor scale. However, many human patients suffer from permanent loss of motor function following spinal cord injury. While rats are the most understood animal model, major differences in sensorimotor pathways between quadrupeds and bipeds need to be considered. Understanding the major differences between the sensorimotor pathways of rats, non-human primates, and humans is a start to improving targets for treatments of human spinal cord injury. This review will discuss the neuroplasticity of the brain and spinal cord after spinal cord injury in rats, non-human primates, and humans. A brief overview of emerging interventions to induce plasticity in humans with spinal cord injury will also be discussed.

Peroneal nerve decompression

Peroneal neuropathy is a common pathology encountered by neurosurgeons. Symptoms include pain, numbness, and foot drop. When secondary to compression of the nerve at the fibular head, peroneal (fibular) nerve release is a low-risk procedure that can provide excellent results with pain relief and return of function. In this video, the authors highlight key operative techniques to ensure adequate decompression of the nerve while protecting the 3 major branches, including the superficial peroneal nerve, deep peroneal nerve, and recurrent genicular (articular) branches. Key steps include positioning, circumferential nerve dissection, fascial opening, isolation of the major branches, and closure.

The video can be found here: https://youtu.be/0y9oE8w1FIU.

Preoperative Ultrasound-Guided Wire Localization of the Lateral Femoral Cutaneous Nerve

BACKGROUND

Difficulty and sometimes inability to find the lateral femoral cutaneous nerve (LFCN) intraoperatively is well known. Variabilities in the course of the nerve are well documented in the literature. In a previous paper, we defined a tight fascial canal that completely surrounds the LFCN in the proximal thigh. These 2 factors sometimes render finding the nerve intraoperatively, to treat meralgia paresthetica, very challenging.

OBJECTIVE

To explore the use of preoperative ultrasound to minimize operative time and eliminate situations in which the nerve is not found.

METHODS

Since 2011, we have used preoperative ultrasound-guided wire localization (USWL) in 19 cases to facilitate finding the nerve intraoperatively. Data were collected prospectively with recording of the timing from skin incision to identifying the LFCN; this will be referred to as the skin-to-nerve time.

RESULTS

In 2 cases, the localization was incorrect. In the 17 cases in which the LFCN was correctly localized, the skin-to-nerve time ranged from 3 min to 19 min. The mean was 8.5 min, and the median was 8 min.

CONCLUSION

Preoperative USWL is a useful technique that minimizes the time needed to find the LFCN. For the less experienced surgeon, it is extremely valuable. For the experienced surgeon, it can identify anatomical abnormalities such as duplicate nerves, which may not be readily recognizable without ultrasound. Collaboration between the surgeon and the radiologist is very important, especially in the early cases.

Guideline summary review: an evidence-based clinical guideline for the diagnosis and treatment of adult isthmic spondylolisthesis

BACKGROUND CONTEXT

The North American Spine Society's (NASS) Evidence-Based Clinical Guideline for the Diagnosis and Treatment of Adult Isthmic Spondylolisthesis features evidence-based recommendations for diagnosing and treating adult patients with isthmic spondylolisthesis. The guideline is intended to reflect contemporary treatment concepts for symptomatic isthmic spondylolisthesis as reflected in the highest quality clinical literature available on this subject as of June 2013. NASS' guideline on this topic is the only guideline on adult isthmic spondylolisthesis accepted in the Agency for Healthcare Research and Quality's National Guideline Clearinghouse.

PURPOSE

The purpose of the guideline is to provide an evidence-based educational tool to assist spine specialists when making clinical decisions for adult patients with isthmic spondylolisthesis. This article provides a brief summary of the evidence-based guideline recommendations for diagnosing and treating patients with this condition.

STUDY DESIGN

This is a guideline summary review.

METHODS

This guideline is the product of the Adult Isthmic Spondylolisthesis Work Group of NASS' Evidence-Based Clinical Guideline Development Committee. The methods used to develop this guideline are detailed in the complete guideline and technical report available on the NASS website. In brief, a multidisciplinary work group of spine care specialists convened to identify clinical questionsto address in the guideline. The literature search strategy was developed in consultation with medical librarians. Upon completion of the systematic literature search, evidence relevant to the clinical questions posed in the guideline was reviewed. Work group members utilized NASS evidentiary table templates to summarize study conclusions, identify study strengths and weaknesses, and assign levels of evidence. Work group members participated in webcasts and in-person recommendation meetings to update and formulate evidence-based recommendations and incorporate expert opinion when necessary. The draft guidelines were submitted to an internal peer review process and ultimately approved by the NASS Board of Directors. Upon publication, the Adult Isthmic Spondylolisthesis guideline was accepted into the National Guideline Clearinghouse and will be updated approximately every 5 years.

RESULTS

Thirty-one clinical questions were addressed, and the answers are summarized in this article. The respective recommendations were graded according to the levels of evidence of the supporting literature.

CONCLUSIONS

The evidence-based clinical guideline has been created using techniques of evidence-based medicine and best available evidence to aid practitioners in the diagnosis and treatment of adult patients with isthmic spondylolisthesis. The entire guideline document, including the evidentiary tables, literature search parameters, literature attrition flowchart, suggestions for future research, and all of the references, is available electronically on the NASS website at https://www.spine.org/ResearchClinicalCare/QualityImprovement/ClinicalGuidelines.aspx and will remain updated on a timely schedule.

A Vascular Malformation Presenting as a Peripheral Nerve Sheath Tumor

We present the case of a venous malformation (VM) masquerading as a schwannoma. VMs are thin-walled vascular dilations of various sizes that typically present as soft, compressible, blue masses that are associated with pain or dysesthesia. VMs are commonly found in the head and neck as well as the distal extremities. Notably, slow-flow VMs are hypointense on T1-weighted imaging, hyperintense on T2-weighted imaging, and enhance markedly with contrast. However, VMs tend to be poorly circumscribed and fraught with venous lakes and phleboliths. Conservative therapy and sclerotherapy are the primary treatment options. In this case report, we present a VM presenting near the neurovascular bundle of the upper extremity axilla. Our case is unique in that the patient presented with symptoms and imaging qualities characteristic for a peripheral nerve schwannoma.

Intraoperative ultrasound-assisted peripheral nerve surgery

Historically, peripheral nerve surgery has relied on landmarks and fairly extensive dissection for localization of both normal and pathological anatomy. High-resolution ultrasonography is a radiation-free imaging modality that can be used to directly visualize peripheral nerves and their associated pathologies prior to making an incision. It therefore helps in localization of normal and pathological anatomy, which can minimize the need for extensive exposures. The authors found intraoperative ultrasound (US) to be most useful in the management of peripheral nerve tumors and neuromas of nerve branches that are particularly small or have a deep location. This study presents the use of intraoperative US in 5 cases in an effort to illustrate some of the applications of this useful surgical adjunct.

An evidence-based clinical guideline for the diagnosis and treatment of lumbar disc herniation with radiculopathy

BACKGROUND CONTEXT

The objective of the North American Spine Society's (NASS) Evidence-Based Clinical Guideline for the Diagnosis and Treatment of Lumbar Disc Herniation with Radiculopathy is to provide evidence-based recommendations to address key clinical questions surrounding the diagnosis and treatment of lumbar disc herniation with radiculopathy. The guideline is intended to reflect contemporary treatment concepts for symptomatic lumbar disc herniation with radiculopathy as reflected in the highest quality clinical literature available on this subject as of July 2011. The goals of the guideline recommendations are to assist in delivering optimum efficacious treatment and functional recovery from this spinal disorder.

PURPOSE

To provide an evidence-based educational tool to assist spine specialists in the diagnosis and treatment of lumbar disc herniation with radiculopathy.

STUDY DESIGN

Systematic review and evidence-based clinical guideline.

METHODS

This guideline is a product of the Lumbar Disc Herniation with Radiculopathy Work Group of NASS' Evidence-Based Guideline Development Committee. The work group consisted of multidisciplinary spine care specialists trained in the principles of evidence-based analysis. A literature search addressing each question and using a specific search protocol was performed on English-language references found in Medline, Embase (Drugs and Pharmacology), and four additional evidence-based databases to identify articles. The relevant literature was then independently rated using the NASS-adopted standardized levels of evidence. An evidentiary table was created for each of the questions. Final recommendations to answer each clinical question were developed via work group discussion, and grades were assigned to the recommendations using standardized grades of recommendation. In the absence of Level I to IV evidence, work group consensus statements have been developed using a modified nominal group technique, and these statements are clearly identified as such in the guideline.

RESULTS

Twenty-nine clinical questions were formulated and addressed, and the answers are summarized in this article. The respective recommendations were graded by strength of the supporting literature, which was stratified by levels of evidence.

CONCLUSIONS

The clinical guideline has been created using the techniques of evidence-based medicine and best available evidence to aid practitioners in the care of patients with symptomatic lumbar disc herniation with radiculopathy. The entire guideline document, including the evidentiary tables, suggestions for future research, and all the references, is available electronically on the NASS Web site at http://www.spine.org/Pages/PracticePolicy/ClinicalCare/ClinicalGuidlines/Default.aspx and will remain updated on a timely schedule.

Adenocarcinoma of the prostate involving the lumbosacral plexus: MRI evidence to support direct perineural spread

BACKGROUND

Prostate adenocarcinoma, which may recur despite aggressive treatment, has the potential to spread to the lumbosacral plexus. This intraneural involvement is not widely known and is thought to be from direct perineural spread. We hypothesized that high-resolution imaging could provide supportive evidence for this mechanism.

METHODS

The clinical data and imaging studies (magnetic resonance imaging, MRI, and positron emission tomography/computed tomography, PET/CT) of patients evaluated at our institution between 2004 and 2009 for lumbosacral plexopathy due to intraneural prostate carcinoma were retrospectively reviewed.

RESULTS

Four patients presenting with painful lumbosacral plexopathy were found to have intraneural lumbosacral prostate adenocarcinoma. Two patients had involvement of the lumbosacral plexus ipsilateral to the lobe of the prostate most involved with adenocarcinoma at prostatectomy. High-resolution MRI and PET/CT studies revealed similar findings: abnormal soft tissue signal was followed from the prostate (n = 1) or prostatic bed (n = 3) area along the expected course of the pelvic plexus to the level of the sciatic notch, where it involved the sacral spinal nerves and sciatic nerve. Imaging findings were consistent with neoplastic infiltration, which was confirmed at biopsy in three patients.

CONCLUSIONS

The potential for prostate adenocarcinoma to spread to the lumbosacral plexus has, to our knowledge, not been readily appreciated. Because the imaging findings are often subtle, we believe that intraneural lumbosacral plexus involvement may not be uncommon. This study, with the use of high-resolution MRI and PET/CT studies, supports the direct perineural spread of prostate adenocarcinoma via the pelvic plexus to the lumbosacral plexus. This mechanism could also explain cases of leptomeningeal and/or dural-based prostate metastases.

Anterior sacral meningocele in pregnancy. Case report

Anterior sacral meningocele was first described in 1837. Most reported cases were associated with complications, including meningitis and death, because of misdiagnosis or inappropriate surgical approach. The authors present a case of anterior sacral meningocele accidentally discovered during pregnancy and provide unique magnetic resonance imaging documentation. The pathogenesis, management, and surgical technique are discussed.