Preoperative visualization of the greater occipital nerve with magnetic resonance imaging in candidates for occipital nerve decompression for headaches.

Occipital nerve decompression is effective in reducing headache symptoms in select patients with migraine and occipital neuralgia. Eligibility for surgery relies on subjective symptoms and responses to nerve blocks and Onabotulinum toxin A (Botox) injections. No validated objective method exists for detecting occipital headache pathologies. The purpose of the study is to explore the potential of high-resolution Magnetic Resolution Imaging (MRI) in identifying greater occipital nerve (GON) pathologies in chronic headache patients. The MRI protocol included three sequences targeting fat-suppressed fluid-sensitive T2-weighted signals. Visualization of the GON involved generating 2-D image slices with sequential rotation to track the nerve course. Twelve patients underwent pre-surgical MRI assessment. MRI identified four main pathologies that were validated against intra-operative examination: GON entanglement by the occipital artery, increased nerve thickness and hyperintensity suggesting inflammation compared to the non-symptomatic contralateral side, early GON branching with rejoining at a distal point, and a connection between the GON and the lesser occipital nerve. MRI possesses the ability to visualize the GON and identify suspected trigger points associated with headache symptoms. This case series highlights MRI's potential to provide objective evidence of nerve pathology. Further research is warranted to establish MRI as a gold standard for diagnosing extracranial contributors in headaches.

Etiologies of iatrogenic occipital nerve injury: And outcomes following treatment with nerve decompression surgery.

INTRODUCTION: This study analyzed the etiologies and treatment of iatrogenic occipital nerve injuries. METHODS: Patients with occipital neuralgia (ON) who were screened for occipital nerve decompression surgery were prospectively enrolled. Patients with iatrogenic occipital nerve injuries who underwent nerve decompression surgery were identified. Data included surgical history, pain characteristics, and surgical technique. Outcomes included pain frequency (days/month), duration (h/day), intensity (0-10), migraine headache index (MHI), and patient-reported percent-resolution of pain. RESULTS: Among the 416 patients with ON, who were screened for occipital nerve decompression surgery, 12 (2.9%) cases of iatrogenic occipital nerve injury were identified and underwent surgical treatment. Preoperative headache frequency was 30 (±0.0) days/month, duration was 19.4 (±6.9) h, and intensity was 9.2 (±0.9). Neuroma excision was performed in 5 cases followed by targeted muscle reinnervation in 3, nerve cap in 1, and muscle burial in 1. In patients without neuromas, greater occipital nerve decompression and/or lesser occipital nerve neurectomy were performed. At the median follow-up of 12 months (IQR 12-12 months), mean pain frequency was 4.0 (±6.6) pain days/month (p < 0.0001), duration was 6.3 (±8.9) h (p < 0.01), and intensity was 4.4 (±2.8) (p < 0.001). Median patient-reported resolution of pain was 85% (56.3%-97.5%) and success rate was (≥50% MHI improvement) 91.7%. CONCLUSIONS: Iatrogenic occipital nerve injuries can be caused by various surgical interventions, including craniotomies, cervical spine interventions, and scalp tumor resections. The associated pain can be severe and chronic. Iatrogenic ON should be considered in the differential diagnosis of post-operative headaches and can be treated with nerve decompression surgery or neuroma excision with reconstruction of the free nerve end.

The neuroma map: A systematic review of the anatomic distribution, etiologies, and surgical treatment of painful traumatic neuromas.

BACKGROUND: This study analyzed all reported cases of painful traumatic neuromas to better understand their anatomic distribution, etiologies, and surgical treatment. METHODS: PubMed, Embase, Cochrane, and Web of Science were searched in October 2023 for articles describing painful traumatic neuromas. RESULTS: In total, 414 articles reporting 5,562 neuromas were included and categorized into head/neck, trunk, upper extremity, lower extremity, and autonomic nerves. Distribution was as follows: Head/neck: 82 articles reported on 393 neuromas (93.2% iatrogenic) most frequently involving the lingual (44.3%), cervical plexus (14.9%), great auricular (8.5%), inferior/superior alveolar (8.3%), and occipital (7.2%) nerves. Trunk: 47 articles reported on 554 neuromas (92.9% iatrogenic) most commonly involving the intercostal (35.4%), genitofemoral (14.3%), and pudendal (12.9%) nerves. Upper extremity: 159 articles reported on 2079 neuromas (53.3% after amputation) most frequently involving the digital (46.9%), superficial radial (18.3%), and median (7.0%) nerves. Lower extremity: 128 articles reported on 2,531 neuromas (53.0% after amputation) most commonly involving the sural (17.9%), superficial peroneal (17.3%), and saphenous (16.0%) nerves. Autonomic nerves: 15 articles reported on 53 neuromas (100% iatrogenic) most frequently involving the biliary tract (73.9%) and vagus nerve (14.9%). Compared with the extremities, neuromas in the head/neck and trunk had significantly longer symptom duration before surgical treatment and the nerve end was significantly less frequently reconstructed after neuroma excision. CONCLUSION: Painful neuromas are predominantly reported in the extremities yet may occur throughout the body primarily after iatrogenic injury. Knowledge of their anatomic distribution from head to toe will encourage awareness to avoid injury and expedite diagnosis to prevent treatment delay.

Surgical Management of Headache Disorders - A Systematic Review of the Literature.

PURPOSE OF REVIEW: This review article critically evaluates the latest advances in the surgical treatment of headache disorders. RECENT FINDINGS: Studies have demonstrated the effectiveness of innovative screening tools, such as doppler ultrasound, pain drawings, magnetic resonance neurography, and nerve blocks to help identify candidates for surgery. Machine learning has emerged as a powerful tool to predict surgical outcomes. In addition, advances in surgical techniques, including minimally invasive incisions, fat injections, and novel strategies to treat injured nerves (neuromas) have demonstrated promising results. Lastly, improved patient-reported outcome measures are evolving to provide a framework for comparison of conservative and invasive treatment outcomes. Despite these developments, challenges persist, particularly related to appropriate patient selection, insurance coverage, delays in diagnosis and surgical treatment, and the absence of standardized measures to assess and compare treatment impact. Collaboration between medical/procedural and surgical specialties is required to overcome these obstacles.

Reoperation Following Primary Greater Occipital Nerve Decompression Surgery: Incidence, Risk Factors and Outcomes.

BACKGROUND: Although nerve decompression surgery is an effective treatment for refractory occipital neuralgia (ON), a proportion of patients experience recurrence of pain and undergo reoperation. This study analyzes the incidence, risk factors, and outcomes of reoperation following primary greater occipital nerve (GON) decompression. METHODS: 215 patients who underwent 399 primary GON decompressions were prospectively enrolled. Data included patient demographics, past medical and surgical history, reoperation rates, intraoperative findings, surgical technique, and postoperative outcomes in terms of pain frequency (days/month), duration (hours/day), intensity (scale 0-10), and migraine headache index (MHI). Bivariate analyses, univariable and multivariable logistic regression analysis was performed. RESULTS: 27 (6.8%) GON decompressions required reoperation with neurectomy at a median follow-up time of 15.5 months (9.8-40.5). Cervical spine disorders on imaging that did not warrant surgical intervention (OR, 4.88; 95% 1.61-14.79; p<0.01) and radiofrequency ablation (RFA) (OR, 4.20; 95% CI, 1.45-15.2; p<0.05) were significantly associated with higher rates of reoperation. At 12 months postoperatively, patients who underwent reoperation achieved similar mean reductions in pain frequency, duration, intensity and MHI, as compared to patients who underwent only primary decompression (p>0.05). CONCLUSION: Patients with ON who have a history of cervical spine disorders or RFA should be counseled that primary decompression has a higher risk of reoperation, but outcomes are ultimately comparable.

Readability analysis and concept mapping of PROMs used for headache disorders.

OBJECTIVE: To assess the readability and the comprehensiveness of patient-reported outcome measures (PROMs) utilized in primary headache disorders literature. BACKGROUND: As the health-care landscape has evolved toward a patient-centric model, numerous PROMs have been developed to capture treatment outcomes in patients with headache disorders. For these PROMs to advance our understanding of headache disorders and their treatment impact, they must be easy to understand (i.e., reading grade level 6 or less) and comprehensively capture what matters to patients with headache. The aim of this study was to (a) assess the readability of PROMs utilized in headache disorders literature, and (b) assess the comprehensiveness of PROMs by mapping their content to a health-related quality of life framework. METHODS: In this scoping review, recently published systematic reviews were used to identify PROMs used in primary headache disorders literature. Readability analysis was performed at the level of individual items and full PROM using established readability metrics. The content of the PROMs was mapped against a health-related quality-of-life framework by two independent reviewers. RESULTS: In total, 22 PROMs (15 headache disorders related, 7 generic) were included. The median reading grade level varied between 7.1 (interquartile range [IQR] 6.3-7.8) and 12.7 (IQR 11.8-13.2). None of the PROMs were below the recommended reading grade level for patient-facing material (grade 6). Three PROMs, the Migraine-Treatment Assessment Questionnaire, the Eurolight, and the European Quality of Life 5 Dimensions 3 Level Version, were between reading grade levels 7 and 8; the remaining 19 PROMs were above reading grade level 8. In total, the PROMs included 425 items. Most items (n = 134, 32%) assessed physical function (e.g., work, activities of daily living). The remaining items assessed physical symptoms (n = 127, 30%; e.g., pain, nausea), treatment effects on symptoms (n = 65, 15%; e.g., accompanying symptoms relief, headache relief), treatment impact (n = 56, 13%; e.g., function, side effects), psychological well-being (n = 41, 10%; e.g., anger, frustration), social well-being (n = 29, 7%; e.g., missing out on social activities, relationships), psychological impact (n = 14, 3%; e.g., feeling [not] in control, feeling like a burden), and sexual well-being (n = 3, 1%; e.g., sexual activity, sexual interest). Some of the items pertained to treatment (n = 27, 6%), of which most were about treatment type and use (n = 12, 3%; e.g., medication, botulinum toxin), treatment access (n = 10, 2%; e.g., health-care utilization, cost of medication), and treatment experience (n = 9, 2%; e.g., treatment satisfaction, confidence in treatment). CONCLUSION: The PROMs used in studies of headache disorders may be challenging for some patients to understand, leading to inaccurate or missing data. Furthermore, no available PROM comprehensively measures the health-related quality-of-life impact of headache disorders or their treatment, resulting in a limited understanding of patient-reported outcomes. The development of an easy-to-understand, comprehensive, and validated headache disorders-specific PROM is warranted.

Peripheral neural interfaces: Skeletal muscles are hyper-reinnervated according to the axonal capacity of the surgically rewired nerves.

Advances in robotics have outpaced the capabilities of man-machine interfaces to decipher and transfer neural information to and from prosthetic devices. We emulated clinical scenarios where high- (facial) or low-neural capacity (ulnar) donor nerves were surgically rewired to the sternomastoid muscle, which is controlled by a very small number of motor axons. Using retrograde tracing and electrophysiological assessments, we observed a nearly 15-fold functional hyper-reinnervation of the muscle after high-capacity nerve transfer, demonstrating its capability of generating a multifold of neuromuscular junctions. Moreover, the surgically redirected axons influenced the muscle's physiological characteristics, by altering the expression of myosin heavy-chain types in alignment with the donor nerve. These findings highlight the remarkable capacity of skeletal muscles to act as biological amplifiers of neural information from the spinal cord for governing bionic prostheses, with the potential of expressing high-dimensional neural function for high-information transfer interfaces.

Prospective Sensory Outcomes for Targeted Nipple Areola Complex Reinnervation (TNR) in Gender-Affirming Double Incision Mastectomy with Free Nipple Grafting.

OBJECTIVE: This study analyses the anatomy and sensory outcomes of targeted nipple areola complex reinnervation (TNR) in gender-affirming double incision mastectomy with free nipple grafting (FNG). BACKGROUND: TNR is a novel technique to preserve and reconstruct intercostal nerves (ICN) to improve postoperative sensation. There is little evidence on relevant anatomy and outcomes. METHODS: 25 patients were prospectively enrolled. Data included demographics, surgical technique, and axon/fascicle counts. Quantitative sensory evaluation using monofilaments and qualitative patient reported questionnaires were completed preoperatively, and at one, three, six, nine and twelve months postoperatively. RESULTS: 50 mastectomies were performed. Per mastectomy, the median number of ICN found and used was 2 (1-5). Axon and fascicle counts were not significantly different between ICN branches ( P >0.05). BMI ≥30 kg/m 2 and mastectomy weight ≥800 g were associated with significantly worse preoperative sensation ( P <0.05). Compared to preoperative values, NAC sensation was worse at 1 month ( P <0.01), comparable at 3 months ( P >0.05), and significantly better at 12 months ( P <0.05) postoperatively. Chest sensation was comparable to the preoperative measurements at 1 and 3 months ( P >0.05), and significantly better at 12 months ( P <0.05) postoperatively. NAC sensation was significantly better when direct coaptation was performed compared to use of allograft only ( P <0.05), and with direct coaptation of ≥2 branches compared to direct coaptation of a single branch ( P <0.05). All patients reported return of nipple and chest sensation at one year postoperatively and 88% reported return of some degree of erogenous sensation. CONCLUSION: TNR allows for restoration of NAC and chest sensation within 3 months postoperatively. Use of multiple ICN branches and direct coaptation led to the best sensory outcomes.

Refractory occipital neuralgia treatment with nerve decompression surgery: a case series.

Background: The management of refractory occipital neuralgia (ON) can be challenging. Selection criteria for occipital nerve decompression surgery are not well defined in terms of clinical features and best preoperative medical management. Methods: In total, 15 patients diagnosed with ON by a board-certified, fellowship-trained headache specialist and referred to a plastic surgeon for nerve decompression surgery were prospectively enrolled. All subjects received trials of occipital nerve blocks (NB), at least three preventive medications, and onabotulinum toxin (BTX) prior to surgery before referral to a plastic surgeon. Treatment outcomes included headache frequency (headache days/month), intensity (0-10), duration (h), and response to medication/injectable therapies at 12 months postoperatively. Results: Preoperatively, median headache days/month was 30 (20-30), intensity 8 (8-10), and duration 24 h (12-24). Patients trialed 10 (±5.8) NB and 11.7 (±9) BTX cycles. Postoperatively, headache frequency was 5 (0-16) days/month (p < 0.01), intensity was 4 (0-6) (p < 0.01), and duration was 10 (0-24) h (p < 0.01). Median patient-reported percent resolution of ON headaches was 80% (70-85%). All patients reported improvement of comorbid headache disorders, most commonly migraine, and a reduction, discontinuation, or increased effectiveness of medications, NB and BTX. Conclusion: All patients who underwent treatment for refractory ON by a headache specialist and plastic surgeon benefited from nerve decompression surgery in various degrees. The collaborative selection criteria employed in this study may be replicable in clinical practice.

Targeted Nipple Reinnervation in Gender-affirming Mastectomy Using Autologous Nerve Graft.

Our team recently described targeted nipple reinnervation (TNR) during female-to-male gender-affirming mastectomy with free nipple grafting using either direct nerve coaptation or nerve allograft. The goals of TNR are to improve sensation (including erogenous sensation) and prevent numbness, paresthesias, chronic pain, and phantom sensation. Here, we describe our modified technique, which has evolved to use autologous intercostal nerve branches as donor nerves for reinnervation if direct nerve coaptation cannot be achieved. During TNR, the T3-T5 sensory branches are preserved and coapted to the repositioned nipple-areolar complex (NAC). In patients with donor nerves that were not adequate in length to allow for direct coaptation, autologous intercostal nerve branches were not used for coaptation (branches present along the chest wall that would otherwise be lost) or one of the T3-T5 branches were harvested. An end-to-end nerve repair between the autograft and donor nerves was done, and the donor nerve/autograft complex was coapted to the NAC. Targeted muscle reinnervation was performed after autograft harvest to prevent neuroma formation. TNR with intercostal nerve autograft is technically feasible in female-to-male gender-affirming mastectomy with free nipple grafting when direct coaptation is not possible. Chest reinnervation using autologous intercostal nerve branches as donor nerves is another option for reinnervation when the nerves are too short for direct coaptation. Because the collection of long-term data is ongoing, the effectiveness of NAC reinnervation using our technique will be described in a future publication.

Treatment Delay in Patients Undergoing Headache Surgery (Nerve Decompression Surgery).

Background: Although headache surgery has been shown to be an effective treatment option for refractory headache disorders, it has not been included as part of the headache disorder management algorithm by non-surgical providers. This study aims to evaluate the delay in surgical management of patients with headache disorders. In addition, a cost comparison analysis between conservative and operative treatment of headache disorders was performed, and the surgical outcomes of headache surgery were reported. Methods: Among 1112 patients who were screened, 271 (56%) patients underwent headache surgery. Data regarding the onset of headache disorder and pre- and postoperative pain characteristics were prospectively collected. To perform a cost comparison analysis, direct and indirect costs associated with the conservative treatment of headache disorders were calculated. Results: The median duration between onset of headache disorder symptoms and headache surgery was 20 (8.2-32) years. The annual mean cost of conservative treatment of headache disorders was $49,463.78 ($30,933.87-$66,553.70) per patient. Over the 20-year time period before surgery, the mean cost was $989,275.65 ($618,677.31-$1,331,073.99). In comparison, the mean cost of headache surgery was $11,000. The median pain days per month decreased by 16 (0-25) (p<0.001), the median pain intensity reduced by 4 (2-7) (p<0.001), and the median pain duration decreased by 11 hours (0-22) (p<0.001). Conclusion: This study shows that patients experience symptoms of headache disorders for an average of 20 years prior to undergoing headache surgery. Surgical treatment not only significantly improves headache pain but also reduces healthcare costs and should be implemented in the management algorithm of headache disorders.

Functional outcomes between headache surgery and targeted botox injections: A prospective multicenter pilot study.

Introduction: Chronic migraine headaches (MH) are a principal cause of disability worldwide. This study evaluated and compared functional outcomes after peripheral trigger point deactivation surgery or botulinum neurotoxin A (BTA) treatment in patients with MH. Methods: A long-term, multicenter, and prospective study was performed. Patients with chronic migraine were recruited at the Ohio State University and Massachusetts General Hospital and included in each treatment group according to their preference (BTA or surgery). Assessment tools including the Migraine Headache Index (MHI), Migraine Disability Assessment Questionnaire (MIDAS) total, MIDAS A, MIDAS B, Migraine Work and Productivity Loss Questionnaire-question 7 (MWPLQ7), and Migraine-Specific Quality of Life Questionnaire (MSQ) version 2.1 were used to evaluate functional outcomes. Patients were evaluated prior to treatment and at 1, 2, and 2.5 years after treatment. Results: A total of 44 patients were included in the study (surgery=33, BTA=11). Patients treated surgically showed statistically significant improvement in headache intensity as measured on MIDAS B (p = 0.0464) and reduced disability as measured on MWPLQ7 (p = 0.0120) compared to those treated with BTA injection. No statistical difference between groups was found for the remaining functional outcomes. Mean scores significantly improved over time independently of treatment for MHI, MIDAS total, MIDAS A, MIDAS B, and MWPLQ 7 (p<0.05). However, no difference in mean scores over time was observed for MSQ. Conclusions: Headache surgery and targeted BTA injections are both effective means of addressing peripheral trigger sites causing headache pain. However, lower pain intensity and work-related disabilities were found in the surgical group.

Treatment Delay From Onset of Occipital Neuralgia Symptoms to Treatment with Nerve Decompression Surgery: A Prospective Cohort Study.

BACKGROUND: The aim of this study was to a) evaluate the time between onset of occipital neuralgia symptoms and nerve decompression surgery, b) perform a cost comparison analysis between surgical and non-surgical treatment of occipital neuralgia and c) report postoperative results of nerve decompression for occipital neuralgia. METHODS: 1,112 subjects who underwent screening for nerve decompression surgery were evaluated for occipital neuralgia. 367 (33%) patients met the inclusion criteria. Timing of occipital neuralgia symptom onset and pain characteristics were prospectively collected. Cost associated with the non-surgical treatment of occipital neuralgia was calculated for the period between onset of symptoms and surgery. RESULTS: 226 (73%) patients underwent occipital nerve decompression. The average time between onset of occipital neuralgia and surgery was 19 years (7.1-32). Postoperatively, the median number of pain days per month decreased by 17 (0-26, 57%) (p < 0.001), the median pain intensity decreased by 4 (2-8, 44%) (p < 0.001), and median pain duration in hours was reduced by 12 (2-23, 50%) (p < 0.001). The annual mean cost of non-surgical occipital neuralgia treatment was $28,728.82 ($16,419.42-$41,198.41) per patient. The mean cost during the 19-year timeframe prior to surgery was $545,847.75($311,968.90-$782,769.82). CONCLUSION: This study demonstrates that patients suffer from occipital neuralgia for an average of 19 years prior to undergoing surgery. Nerve decompression reduces symptom severity significantly and should be considered earlier in the treatment course of occipital neuralgia that is refractory to conservative treatment to prevent patient morbidity and decrease direct and indirect healthcare costs. IRB REGISTRATION NUMBER & NAME: Weill Cornell Medicine: 23-04025985, Prospective Cohort Study Investigating Long- Term Outcomes After Headache Surgery.The Massachusetts General Hospital: 2012P001527, Correlation of pre-operative pain self-efficacy and post-operative migraine-specific symptoms and disability.

Anatomic Anomalies of the Nerves Treated during Headache Surgery.

Background: Headache surgery is a well-established, viable option for patients with chronic head pain/migraines refractory to conventional treatment modalities. These operations involve any number of seven primary nerves. In the occipital region, the surgical targets are the greater, lesser, and third occipital nerves. In the temporal region, they are the auriculotemporal and zygomaticotemporal nerves. In the forehead, the supraorbital and supratrochlear are targeted. The typical anatomic courses of these nerves are well established and documented in clinical and cadaveric studies. However, variations of this "typical" anatomy are quite common and relatively poorly understood. Headache surgeons should be aware of these common anomalies, as they may alter treatment in several meaningful ways. Methods: In this article, we describe the experience of five established headache surgeons encompassing over 4000 cases with respect to the most common anomalies of the nerves typically addressed during headache surgery. Descriptions of anomalous nerve courses and suggestions for management are offered. Results: Anomalies of all seven nerves addressed during headache operations occur with a frequency ranging from 2% to 50%, depending on anomaly type and nerve location. Variations of the temporal and occipital nerves are most common, whereas anomalies of the frontal nerves are relatively less common. Management includes broader dissection and/or transection of accessory injured nerves combined with strategies to reduce neuroma formation such as targeted reinnervation or regenerative peripheral nerve interfaces. Conclusions: Understanding these myriad nerve anomalies is essential to any headache surgeon. Implications are relevant to preoperative planning, intraoperative dissection, and postoperative management.

Feasibility of Ultrasound Measurements of Peripheral Sensory Nerves in Head and Neck Area in Healthy Subjects.

Background: Current diagnostic methods for nerve compression headaches consist of diagnostic nerve blocks. A less-invasive method that can possibly aid in the diagnosis is ultrasound, by measuring the cross-sectional area (CSA) of the affected nerve. However, this technique has not been validated, and articles evaluating CSA measurements in the asymptomatic population are missing in the current literature. Therefore, the aim of this study was to determine the feasibility of ultrasound measurements of peripheral extracranial nerves in the head and neck area in asymptomatic individuals. Methods: The sensory nerves of the head and neck in healthy individuals were imaged by ultrasound. The CSA was measured at anatomical determined measurement sites for each nerve. To determine the feasibility of ultrasound measurements, the interrater reliability and the intrarater reliability were determined. Results: In total, 60 healthy volunteers were included. We were able to image the nerves at nine of 11 measurement sites. The mean CSA of the frontal nerves ranged between 0.80 ± 0.42 mm2 and 1.20 ± 0.43 mm2, the mean CSA of the occipital nerves ranged between 2.90 ± 2.73 mm2 and 3.40 ± 1.91 mm2, and the mean CSA of the temporal nerves ranged between 0.92 ± 0.26 mm2 and 1.40 ± 1.11 mm2. The intrarater and interrater reliability of the CSA measurements was good (ICC: 0.75-0.78). Conclusions: Ultrasound is a feasible method to evaluate CSA measurements of peripheral extracranial nerves in the head and neck area. Further research should be done to evaluate the use of ultrasound as a diagnostic tool for nerve compression headache.

The Use of Nerve Caps after Nerve Transection in Headache Surgery: Cadaver and Case Reports.

Background: Nerve transection with nerve reconstruction is part of the treatment algorithm for patients with refractory pain after greater occipital nerve (GON) and lesser occipital nerve (LON) decompression or during primary decompression when severe nerve injury or neuroma formation is present. Importantly, the residual nerve stump is often best addressed via contemporary nerve reconstruction techniques to avoid recurrent pain. As a primary aim of this study, nerve capping is explored as a potential viable alternative that can be utilized in certain headache cases to mitigate pain. Methods: The technical feasibility of nerve capping after GON/LON transection was evaluated in cadaver dissections and intraoperatively. Patient-reported outcomes in the 3- to 4-month period were compiled from clinic visits. At 1-year follow-up, subjective outcomes and Migraine Headache Index scores were tabulated. Results: Two patients underwent nerve capping as a treatment for headaches refractory to medical therapy and surgical decompressions with significant improvement to total resolution of pain without postoperative complications. These improvements on pain frequency, intensity, and duration remained stable at a 1-year time point (Migraine Headache Index score reductions of -180 to -205). Conclusions: Surgeons should be equipped to address the proximal nerve stump to prevent neuroma and neuropathic pain recurrence. Next to known contemporary nerve reconstruction techniques such as targeted muscle reinnervation/regenerative peripheral nerve interface and relocation nerve grafting, nerve capping is another viable method for surgeons to address the proximal nerve stump in settings of GON and LON pain. This option exhibits short operative time, requires only limited dissection, and yields significant clinical improvement in pain symptoms.

Adaptive conductive electrotherapeutic scaffolds for enhanced peripheral nerve regeneration and stimulation.

BACKGROUND: While peripheral nerve stimulation (PNS) has shown promise in applications ranging from peripheral nerve regeneration to therapeutic organ stimulation, clinical implementation has been impeded by various technological limitations, including surgical placement, lead migration, and atraumatic removal. METHODS: We describe the design and validation of a platform technology for nerve regeneration and interfacing: adaptive, conductive, and electrotherapeutic scaffolds (ACESs). ACESs are comprised of an alginate/poly-acrylamide interpenetrating network hydrogel optimized for both open surgical and minimally invasive percutaneous approaches. FINDINGS: In a rodent model of sciatic nerve repair, ACESs significantly improved motor and sensory recovery (p < 0.05), increased muscle mass (p < 0.05), and increased axonogenesis (p < 0.05). Triggered dissolution of ACESs enabled atraumatic, percutaneous removal of leads at forces significantly lower than controls (p < 0.05). In a porcine model, ultrasound-guided percutaneous placement of leads with an injectable ACES near the femoral and cervical vagus nerves facilitated stimulus conduction at significantly greater lengths than saline controls (p < 0.05). CONCLUSION: Overall, ACESs facilitated lead placement, stabilization, stimulation, and atraumatic removal, enabling therapeutic PNS as demonstrated in small- and large-animal models. FUNDING: This work was supported by K. Lisa Yang Center for Bionics at MIT.

The Peripheral Nerve Surgeon's Role in the Management of Neuropathic Pain.

Neuropathic pain (NP) underlies significant morbidity and disability worldwide. Although pharmacologic and functional therapies attempt to address this issue, they remain incompletely effective for many patients. Peripheral nerve surgeons have a range of techniques for intervening on NP. The aim of this review is to enable practitioners to identify patients with NP who might benefit from surgical intervention. The workup for NP includes patient history and specific physical examination maneuvers, as well as imaging and diagnostic nerve blocks. Once diagnosed, there is a range of options surgeons can utilize based on specific causes of NP. These techniques include nerve decompression, nerve reconstruction, nerve ablative techniques, and implantable nerve-modulating devices. In addition, there is an emerging role for preoperative involvement of peripheral nerve surgeons for cases known to carry a high risk of inducing postoperative NP. Lastly, we describe the ongoing work that will enable surgeons to expand their armamentarium to better serve patients with NP.

Relative Pain Reduction and Duration of Nerve Block Response Predict Outcomes in Headache Surgery: A Prospective Cohort Study.

BACKGROUND: Experts agree that nerve block (NB) response is an important tool in headache surgery screening. However, the predictive value of NBs remains to be proven in a prospective fashion. METHODS: Pre-NB and post-NB visual analogue pain scores (0 to 10) and duration of NB response were recorded prospectively. Surgical outcomes were recorded prospectively by calculating the Migraine Headache Index (MHI) preoperatively and postoperatively at 3 months, 12 months, and every year thereafter. RESULTS: The study population included 115 patients. The chance of achieving MHI percentage improvement of 80% or higher was significantly higher in subjects who reported relative pain reduction of greater than 60% following NB versus less than or equal to 60% [63 of 92 (68.5%) versus 10 of 23 (43.5%); P = 0.03]. Patients were more likely to improve their MHI 50% or more with relative pain reduction of greater than 40% versus 40% or less [82 of 104 (78.8%) versus five of 11 (45.5%); P = 0.01]. In subjects with NB response of greater than 15 days, 10 of 13 patients (77.0%) experienced MHI improvement of 80% or greater. Notably, all of these patients (100%) reported MHI improvement of 50% or greater, with mean MHI improvement of 88%. Subjects with a NB response of 24 hours or more achieved significantly better outcomes than patients with a shorter response (72.7% ± 37.0% versus 46.1% ± 39.7%; P = 0.02). However, of 14 patients reporting NB response of less than 24 hours, four patients had MHI improvement of 80% or greater, and seven, of 50% or greater. CONCLUSIONS: Relative pain reduction and duration of NB response are predictors of MHI improvement after headache surgery. NBs are a valuable tool to identify patients who will benefit from surgery. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.