RPNI, TMR, and Reset Neurectomy/Relocation Nerve Grafting after Nerve Transection in Headache Surgery

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.

Novel Utilization of the Regenerative Peripheral Nerve Interface Technique after Unsuccessful Nerve Release for Bilateral Frontal Migraines

Regenerative peripheral nerve interface (RPNI) is a surgical technique whose indications include preventing or treating painful neuromas after amputation or peripheral nerve injuries. The procedure involves implanting the distal end of a transected peripheral nerve containing sensory fibers into a selected free muscle graft. Although RPNI procedures have primarily been used after limb amputations, select case reports detail the potential for RPNI to mitigate other sources of neuropathic pain, introducing novel uses to its clinical utility. We present the case of a 49-year-old woman who presented to our clinic in June 2021 with chronic frontal migraines with right retro-orbital pain. Bilateral supraorbital and supratrochlear nerve releases with fat grafting were performed in August 2018 via a blepharoplasty approach; however, this procedure was unsuccessful in reducing her neuropathic pain. After discussion with the patient, we elected to proceed with transection of bilateral supraorbital and supratrochlear nerves with RPNI. The postoperative course was uneventful. Follow-up visits up to 1-year postoperative revealed that she had adequate pain control, discontinued her migraine medications, and reported satisfaction with the procedure. The novel RPNI surgical technique may be a low-risk adjunctive option in the surgical management of refractory supraorbital and supratrochlear neuralgia. Future studies should include a prospective randomized controlled trial comparing supraorbital and supratrochlear neurectomy alone to neurectomy with RPNI in refractory supraorbital and supratrochlear neuralgia management. Further exploration of RPNI may reveal additional uses and modifications, which may revolutionize the treatment of neuralgia and other similar ailments.

Regenerative Peripheral Nerve Interface Surgery for the Management of Chronic Posttraumatic Neuropathic Pain

Chronic pain resulting from peripheral nerve injury remains a common issue in the United States and affects 7 to 10% of the population. Regenerative Peripheral Nerve Interface (RPNI) surgery is an innovative surgical procedure designed to treat posttraumatic neuropathic pain, particularly when a symptomatic neuroma is present on clinical exam. RPNI surgery involves implantation of a transected peripheral nerve into an autologous free muscle graft to provide denervated targets to regenerating axons. RPNI surgery has been found in animal and human studies to be highly effective in addressing postamputation pain. While most studies have reported its uses in the amputation patient population for the treatment of neuroma and phantom limb pain, RPNI surgery has recently been used to address refractory headache, postmastectomy pain, and painful donor sites from the harvest of neurotized flaps. This review summarizes the current understanding of RPNI surgery for the treatment of chronic neuropathic pain.

Secondary Trigger Point Deactivation Surgery for Nerve Compression Headaches: A Scoping Review

Background

Primary trigger point deactivation surgery has been successful in reducing or eliminating nerve compression headaches between 79% and 90% of the time. The aim of this review article was to discuss the factors that contribute to index trigger point deactivation surgery failure, the importance of reevaluating trigger points following failure, and the options for secondary surgery.

Methods

A literature search was performed using a combination of keywords involving "chronic headache" and "nerve deactivation surgery," in databases until February 2023.

Results

Data of 1071 patients were evaluated and included (11 articles). The failure rate after index trigger point deactivation surgery occurs is approximately 12%, primarily due to incomplete primary trigger point deactivation. Secondary trigger points may not appear until the primary trigger is eliminated, which occurs in 17.8% of patients. Reevaluation of previously diagnosed trigger points as well as uncovered trigger points and additional preoperative testing is indicated to help determine candidacy for further surgical deactivation. To address scarring that could contribute to failure, corticosteroid injection, acellular dermal matrix, adipofascial fat, or expanded polytetrafluoroethylene sleeves have been described with beneficial effects. For neuroma management, regenerative peripheral nerve interface, targeted muscle reinnervation, a combination of both, relocation nerve grafting, or nerve capping have also been described. Neurectomy can be performed when patients prefer anesthesia and/or paresthesia over current pain symptoms.

Conclusion

Secondary trigger point deactivation surgery is indicated when there is suspicion of incomplete deactivation, internal scarring, neuroma, or newly-diagnosed trigger points.

Nerve Capping Techniques for Neuroma Management: A Comprehensive Literature Review

BACKGROUND/AIM OF THE STUDY

Nerve capping is a method of neuroma treatment or prevention that consists of the transplantation of a proximal nerve stump into an autograft or other material cap, after surgical removal of the neuroma or transection of the nerve. The aim was to reduce neuroma formation and symptoms by preventing neuronal adhesions and scar tissue. In this narrative literature review, we summarize the studies that have investigated the effectiveness of nerve capping for neuroma management to provide clarity and update the clinician's knowledge on the topic.

METHODS

A systematic electronic search following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria was performed in the PubMed database combining "neuroma," "nerve," "capping," "conduit," "treatment," "management," "wrap," "tube," and "surgery" as search terms. English-language clinical studies on humans and animals that described nerve capping as a treatment/prevention technique for neuromas were then selected based on a full-text article review. The data from the included studies were compiled based on the technique and material used for nerve capping, and technique and outcomes were reviewed.

RESULTS

We found 10 applicable human studies from our literature search. Several capping materials were described: epineurium, nerve, muscle, collagen nerve conduit, Neurocap (synthetic copolymer of lactide and caprolactone, which is biocompatible and resorbable), silicone rubber, and collagen. Overall, 146 patients were treated in the clinical studies. After surgery, many patients were completely pain-free or had considerable improvement in pain scores, whereas some patients did not have improvement or were not satisfied after the procedure. Nerve capping was used in 18 preclinical animal studies, using a variety of capping materials including autologous tissues, silicone, and synthetic nanofibers. Preclinical studies demonstrated successful reduction in rates of neuroma formation.

CONCLUSIONS

Nerve capping has undergone major advancements since its beginnings and is now a useful option for the treatment or prevention of neuromas. As knowledge of peripheral nerve injuries and neuroma prevention grows, the criterion standard neuroprotective material for enhancement of nerve regeneration can be identified and applied to produce reliable surgical outcomes.

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.

Vascularized Denervated Muscle Targets for Headache Surgery-Presentation and Surgical Management

Patients with substantial trauma to their occipital nerves and those with recurrent or persistent chronic headaches after occipital nerve decompression surgery require transection of their greater occipital and/or lesser occipital nerves to control debilitating pain. Current techniques, such as burying the transected nerve stump in nearby muscle, do not prevent neuroma formation, and more advanced techniques, such as targeted muscle reinnervation and regenerative peripheral nerve interface, have demonstrated only short-term anecdotal success in the context of headache surgery. Vascularized denervated muscle targets (VDMTs) are a novel technique to address the proximal nerve stump after nerve transection that has shown promise to improve chronic nerve pain and prevent neuroma formation. However, VDMTs have not been described in the context of headache surgery. Here authors describe the etiology, workup, and surgical management of 2 patients with recurrent occipital neuralgia who developed vexing neuromas after previous surgery and were successfully treated with VDMTs, remaining pain-free at 3-year follow-up.

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.

Expanding Our Role in Headache Management: A Systematic Review and Algorithmic Approach to Surgical Management of Postcraniotomy Headache

BACKGROUND

Chronic postcraniotomy headache (PCH) is common and debilitating. Unfortunately, the literature on this topic is sparse without clear management algorithms. Possible etiologies of PCH include nerve injury and/or entrapment, hardware, dural adhesions, or musculoskeletal injury. The purpose of this study was to present the results of both a systematic review of the literature and a single-center case series, both of which informed the development of a novel treatment algorithm that may be applied to this patient population.

METHODS

Using Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, we performed a systematic review of the literature, identifying articles describing the surgical management of PCH. A retrospective chart review was performed to identify patients who met the criteria for PCH treated at our institution. A patient's history and physical examination determined the etiology and management, and pain severity scores were the primary outcome measured.

RESULTS

Nineteen articles encompassing 131 patients described surgical management techniques for PCH. 83 patients (63.3%) had complete resolution of pain (χ2 = 52.1, P < 0.0001). At our institution, 19 patients underwent surgical management for PCH. A significant reduction in pain scores from 7.57 to 2.16 (P < 0.001) was demonstrated, and 84 percent of patients achieved complete or significant pain reduction.

CONCLUSIONS

Through a literature review and our own case series, we demonstrate that surgical management of PCH can achieve remarkable results. Plastic surgeons, with their expanding role in treating migraine and headaches, are well suited to manage these patients. We present an algorithmic approach to simplify the management of this common and debilitating condition.

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.

Nonsurgical Treatment of Neuralgia and Cervicogenic Headache: A Systematic Review and Meta-analysis

Background:

Extracranial compression of peripheral sensory nerves is one of many origins of chronic headaches. Identifying these patients can be difficult, and they are often diagnosed with neuralgia or cervicogenic headache. The recent literature provides the outcomes of surgical decompression in patients with these headaches. This study aimed to give an overview of the current literature on the nonsurgical treatment options and to evaluate the effectiveness of these treatments in patients with neuralgia and cervicogenic headache.

Methods:

Databases were searched to identify all published clinical studies investigating nonsurgical treatment outcomes in patients with neuralgia or cervicogenic headaches. Studies that reported numerical pain scores, nonnumerical pain scores, headache-free days, or the number of adverse events after nonsurgical treatment were included.

Results:

A total of 22 articles were included in qualitative analysis. The majority of studies included patients who received injection therapy. Treatment with oral analgesics achieved good results in only 2.5% of the patients. Better outcomes were reported in patients who received local anesthetics injection (79%) and corticosteroid injection (87%). Treatment with botulinum toxin injection yielded the highest percentage of good results (97%; 95% CI, 0.81–1.00). The duration of headache relief after injection therapy varied from 30 minutes to 5 months.

Conclusions:

The nonsurgical treatment of patients with neuralgia or cervicogenic headache is challenging. Injection therapy in patients with these types of headaches achieved good pain relief but only for a limited time. Surgical decompression may result in long-lasting pain relief and might be a more sustainable treatment option.