Intraoperative anatomical variations during greater occipital nerve decompression

Comprehensive Criteria for Differential Diagnosis and a Surgical Management Algorithm for Occipital Neuralgia and Migraine Headaches

The differential diagnoses and nuances of the surgical management of occipital migraine and occipital neuralgia have not been clearly discussed in the available literature. This study aims to highlight additional diagnostic features and offers an algorithm for the surgical treatment of occipital migraine and occipital neuralgia based on the vast experience of the senior author spanning over 23 years. A retrospective cohort study was conducted to review the number and distribution of patients who underwent surgical treatment for occipital migraine headaches and neuralgia and the signs and symptoms observed. Among the 660 patients who underwent surgical treatment for headaches within the territory of the greater occipital nerves, 86 patients underwent isolated deactivation of the greater occipital site (site IV) or combined greater and lesser occipital sites (site IV and site VI surgical). Within the isolated occipital headache group, 43 patients met the criteria for migraine headaches and 43 for occipital neuralgia. Our additional observation on the differences between the occipital neuralgia and migraine groups included that occipital neuralgia is more commonly unilateral, less commonly familial, and more commonly associated with a whiplash-type injury. In addition, the patient with occipital neuralgia can consistently identify the distinct point of pain using the index finger. An ultrasound Doppler signal can also be detected at the pain site and a pulse is often palpable in the site identified by the patient. Occipital neuralgia is also commonly continuous and unrelenting, with occasional spikes of shooting pain, and is less likely to respond to botulinum toxin-A injection. Patients with occipital neuralgia often have a single-site headache while patients with migraine headaches often suffer from headaches in multiple sites. Additional clinical criteria are offered for the differential diagnosis of occipital migraine headaches and occipital neuralgia based on the vast experience of the senior author and the developed surgical management algorithm.

Morphological features of the greater occipital nerve and its possible importance for interventional procedures

Being one of the most prevalent neurological symptoms, headaches are burdensome and costly. Blocks and decompression surgeries of the greater occipital nerve (GON) have been frequently used for migraine, cervicogenic headache, and occipital neuralgia which are classified under headache by International Headache Society. Knowledge of complex anatomy of GON is crucial for its decompression surgery and block. This study was performed to elucidate anatomical features of this nerve in detail. Forty-one cadavers were dissected bilaterally. According to its morphological features, GON was classified into four main types that included 18 subtypes. Moreover, potential compression points of the nerve were defined. The number of branches of the GON up to semispinalis capitis muscle and the number of its branches that were sent to this muscle were recorded. The most common variant was that the GON pierced the aponeurosis of the trapezius muscle, curved around the lower edge of the obliquus capitis inferior muscle, and was loosely attached to the obliquus capitis inferior muscle (Type 2; 61 sides, 74.4%). In the subtypes, the most common form was Type 2-A (44 sides, 53.6%), in which the GON pierced the aponeurosis of each of the trapezius muscle and fibers of semispinalis muscle at one point and there was a single crossing of the GON and occipital artery. Six potential compression points of the GON were detected. The first point was where the nerve crossed the lower border of the obliquus capitis inferior muscle. The second and third points were at its piercing of the semispinalis capitis muscle and the muscle fibers/aponeurosis of the trapezius, respectively. Fourth, fifth, and sixth compression points of GON were located where the GON and occipital artery crossed each other for the first, second, and third times, respectively. On 69 sides, 1-4 branches of the GON up to the semispinalis capitis muscle were observed (median = 1), while 1-4 branches of GON were sent to the semispinalis capitis muscle on 67 sides (median = 1). The novel anatomical findings described in this study may play a significant role in increasing the success rate of invasive interventions related with the GON.

Minimally Invasive Nerve- and Muscle-Sparing Surgical Decompression for Occipital Neuralgia

BACKGROUND

Occipital neuralgia is a well-defined type of headache, and its treatment algorithm is still debated across medical specialties. From the analysis of the literature, it appears that surgical decompression of the occipital nerves is the most effective invasive approach to improve the quality of life of patients with occipital neuralgia refractory to medications. The authors describe here a minimally invasive nerve- and muscle-sparing technique to decompress the occipital nerves.

METHODS

The results in terms of reduction of migraine days per month, use of medications, pain evaluation, and decrease in Migraine Headache Index were analyzed by means of a retrospective chart review of 87 patients who underwent nerve- and muscle-sparing surgical decompression of the greater and lesser monolateral or bilateral occipital nerves in their institution and were followed up for at least 12 months. The surgical technique is described in detail.

RESULTS

Surgical decompression significantly reduced occipital neuralgia burden (at least 50% improvement) in 91% of patients, with 45% reporting a complete remission of occipital pain. Days with pain per month decreased by 80%, chronic background pain intensity decreased by 81%, and pain intensity during crisis decreased by 76%. Accordingly, drug use dropped by approximately 70%. Only minor complications were reported in four patients.

CONCLUSIONS

The described technique could contribute to and further support surgical decompression as the first option among the invasive approaches to treat occipital neuralgia. Results corroborate previous findings, adding a less-invasive, nerve- and muscle-sparing approach.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

A Correlation between Upper Extremity Compressive Neuropathy and Nerve Compression Headache

BACKGROUND

Compressive neuropathies of the head/neck that trigger headaches and entrapment neuropathies of the extremities have traditionally been perceived as separate clinical entities. Given significant overlap in clinical presentation, treatment, and anatomical abnormality, the authors aimed to elucidate the relationship between nerve compression headaches and carpal tunnel syndrome, and other upper extremity compression neuropathies.

METHODS

One hundred thirty-seven patients with nerve compression headaches who underwent surgical nerve deactivation were included. A retrospective chart review was conducted and the prevalence of carpal tunnel syndrome, thoracic outlet syndrome, and cubital tunnel syndrome was recorded. Patients with carpal tunnel syndrome, cubital tunnel syndrome, and thoracic outlet syndrome who had a history of surgery and/or positive imaging findings in addition to confirmed diagnosis were included. Patients with subjective report of carpal tunnel syndrome/thoracic outlet syndrome/cubital tunnel syndrome were excluded. Prevalence was compared to general population data.

RESULTS

The cumulative prevalence of upper extremity neuropathies in patients undergoing surgery for nerve compression headaches was 16.7 percent. The prevalence of carpal tunnel syndrome was 10.2 percent, which is 1.8- to 3.8-fold more common than in the general population. Thoracic outlet syndrome prevalence was 3.6 percent, with no available general population data for comparison. Cubital tunnel syndrome prevalence was comparable between groups.

CONCLUSIONS

The degree of overlap between nerve compression syndromes of the head/neck and upper extremity suggests that peripheral nerve surgeons should be aware of this correlation and screen affected patients comprehensively. Similar patient presentation, treatment, and anatomical basis of nerve compression make either amenable to treatment by nerve surgeons, and treatment of both entities should be an integral part of a formal peripheral nerve surgery curriculum.

Trigger-Site Deactivation Surgery for Nerve Compression Headaches

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Identify patients who are candidates for headache surgery. 2. Counsel the patient preoperatively with regard to success rates, recovery, and complications. 3. Develop a surgical plan for primary and secondary nerve decompression. 4. Understand the surgical anatomy at all trigger sites. 5. Select appropriate International Classification of Diseases, Tenth Revision, and CPT codes.

SUMMARY

Headache surgery encompasses release of extracranial peripheral sensory nerves at seven sites. Keys to successful surgery include correct patient selection, detailed patient counseling, and meticulous surgical technique. This article is a practical step-by-step guide, from preoperative assessment to surgery and postoperative recovery. International Classification of Diseases, Tenth Revision, and CPT codes, in addition to complications and salvage procedures, are discussed. Intraoperative photographs, videos, and screening questionnaires are provided.

Muscle Fascia Changes in Patients with Occipital Neuralgia, Headache, or Migraine

SUMMARY

In an ongoing effort to understand the pathogenesis of occipital neuralgia/headache/migraine, it is critical to describe the anatomical/tissue changes encountered during surgery. Greater occipital nerve anatomical studies mainly focus on the greater occipital nerve course through muscle/fascial planes and interaction with the occipital vessels. However, structural soft-tissue changes have not been described in detail. Anecdotally, trapezius fascia is thickened at the greater occipital nerve trigger site. This study further investigates this observation. Patients undergoing greater occipital nerve decompression surgery were enrolled prospectively in this observational study (n = 92). Tissue changes were recorded intraoperatively. The resulting data were examined. Trapezius fascia was more than 3 mm thick and appeared fibrotic in 86 patients (94 percent), whereas semispinalis muscle appeared normal in all subjects. The greater occipital nerve was macroscopically abnormal, defined as edematous, flattened, and discolored in 29 cases (32 percent). The occipital artery interacted significantly with the greater occipital nerve in 88 percent of cases. The authors conclude that the tissue structure is abnormal in patients undergoing greater occipital nerve decompression surgery. This is the first study that describes the prevalence of thickened and fibrotic appearing trapezius fascia at the occipital trigger site, a phenomenon encountered in the vast majority of patients (94 percent). This structural anomaly has a resemblance to thickened fascial tissues seen in other nerve compression syndromes, and could be related to microtrauma/overuse or actual trauma in the head and neck region.

Patient Pain Sketches Can Predict Surgical Outcomes in Trigger-Site Deactivation Surgery for Headaches

BACKGROUND

Patient selection for headache surgery is an important variable to ensure successful outcomes. In the authors' experience, a valuable method to visualize pain/trigger sites is to ask patients to draw their pain. The authors have found that there are pathognomonic pain patterns for each site, and typically do not operate on patients with atypical pain sketches, as they believe such patients are poor surgical candidates. However, a small subset of these atypical patients undergo surgery based on other strong clinical findings. In this study, the authors attempt to quantify this clinical experience.

METHODS

Patients were prospectively enrolled and completed pain sketches at screening. One hundred six diagrams were analyzed/categorized by two independent, blinded reviewers as follows: (1) typical (pain over nerve distribution, expected radiation); (2) intermediate (pain over nerve distribution, atypical radiation); or (3) atypical (pain outside of normal nerve distribution, atypical radiation). Preoperative and postoperative Migraine Headache Index was compared between subgroups using unpaired t tests.

RESULTS

Migraine Headache Index improvement was 73 ± 38 percent in the typical group, 78 ± 30 percent in the intermediate group, and 30 ± 40 percent in the atypical group. There was a significant difference in Migraine Headache Index between the typical and atypical groups (p = 0.03) and between the intermediate and atypical groups (p < 0.01). The chance of achieving Migraine Headache Index improvement greater than 30 percent in the atypical group was 20 percent.

CONCLUSIONS

Patient pain sketches classified as atypical (facial pain, atypical pain point origin, diffuse pain) can predict poor outcomes in headache surgery. As the authors continue to develop patient selection criteria for headache surgery, patient sketches should be considered as an effective, cheap, and simple-to-interpret tool for selecting candidates for surgery.

Great Occipital Nerve as Donor Nerve for Neurotization With Suprascapular Nerve in Total Braqchial Plexus Injuries: Nerve Transfer Technique

Complete brachial plexus injuries continue to be a technical and strategic challenge in surgical reconstruction to restore function and sensitivity in a paralyzed and insensitive limb. The use of donor's nerves to perform neurotizations is limited, and, in reconstructions for preganglionic lesions, these techniques have gained prominence, even leaving comorbidities in the donor sites. The purpose of this paper is to present the great suboccipital nerve as a new donor nerve bases on our anatomic research with the transfer technique from the great occipital nerve to the suprascapular nerve.

Greater Occipital Nerve Block for the Treatment of Chronic Migraine Headaches: A Systematic Review and Meta-Analysis

BACKGROUND

Few treatment options exist for chronic migraine headaches, with peripheral nerve blocks having long been used to reduce the frequency and severity of migraines. Although the therapeutic effects have been observed in clinical practice, the efficacy has never been fully studied. In the past decade, however, several randomized controlled clinical trials have been conducted to assess the efficacy of greater occipital nerve block in the treatment of chronic migraine headaches.

METHODS

A systematic review of the literature was performed in the citation databases PubMed, Embase, MEDLINE, and the Cochrane Library. The initial search of databases yielded 259 citations, of which 33 were selected as candidates for full-text review. Of these, nine studies were selected for inclusion in this meta-analysis.

RESULTS

Studies were analyzed that reported mean number of headache days per month in both intervention and control groups. A total of 417 patients were studied, with a pooled mean difference of -3.6 headache days (95 percent CI, -1.39 to -5.81 days). This demonstrates that greater occipital nerve block intervention significantly reduced the frequency of migraine headaches compared with controls (p < 0.00001). Pooled mean difference in pain scores of -2.2 (95 percent CI, -1.56 to -2.84) also demonstrated a significant decrease in headache severity compared with controls (p < 0.0121).

CONCLUSIONS

Greater occipital nerve blocking should be recommended for use in migraine patients, particularly those that may require future surgical intervention. The block may act as an important stepping stone for patients experiencing migraine headache because of its usefulness for potentially assessing surgical candidates for nerve decompression.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.