Occipital nerve stimulation in pediatric patients with refractory occipital neuralgia.

PURPOSE: Occipital neuralgia (ON) is a disabling problem within the pediatric population. Many of these patients fail medical therapies and continue to suffer without further surgical management. Occipital nerve stimulation (ONS) is used to treat ON in the adult population leading to a 72-89% reduction in pain; however, there are limited studies regarding its use in the pediatric population. In this study, we examined the outcomes of ONS in pediatric patients with medically refractory ON. METHODS: We performed a chart review of pediatric patients at our institution who have undergone ONS for the same indications. RESULTS: We identified 3 patients at our institution who underwent ONS trial and/or permanent implantation for ON. One patient had complete pain relief after the trial and declined permanent implantation. The other patient had fewer attacks compared to his pre-trial baseline and controlled them by adjusting his permanent implant stimulation settings. The last patient had near complete relief of her symptoms and no longer required any pain medication. CONCLUSION: Our study highlights the paucity of studies evaluating the utility of ONS in the pediatric ON population. Limited data from both the literature and our institution's experience reveal that pediatric patients may benefit from trial and/or permanent implantation of ONS for medically refractory ON pain.

The Postconcussion Syndrome and Posttraumatic Headaches in Civilians, Soldiers, and Athletes.

Posttraumatic headaches are one of the most common and controversial secondary headache types. After a mild traumatic brain, an estimated 11% to 82% of people develop a postconcussion syndrome, which has been controversial for more than 160 years. Headache is estimated as present in 30% to 90% of patients after a mild head injury. Most headaches are tension-type-like or migraine-like. Headaches in civilians, soldiers, athletes, and postcraniotomy are reviewed. The treatments are the same as for the primary headaches. Persistent posttraumatic headaches can continue for many years.

Neuralgia in the occipital region associated with ipsilateral trigeminal herpes zoster: Three case reports.

BACKGROUND: Nerve fibers related to pain and temperature sensation in the trigeminal nerve territory converge with the upper cervical spinal nerves from the level of the lower medulla oblongata to the upper cervical cord. This structure is called the trigemino-cervical complex and may cause referred pain in the territory of the trigeminal or upper cervical spinal nerves. CASE SERIES: Here, we report three cases of paroxysmal neuralgia in the occipital region with mild conjunctivitis or a few reddish spots in the ipsilateral trigeminal nerve territory. The patients exhibited gradual progression of these reddish spots evolving into vesicles over the course of several days, despite the absence of a rash in the occipital region. The patients were diagnosed with trigeminal herpes zoster and subsequently received antiherpetic therapy. Remarkably, the neuralgia in the occipital region showed gradual amelioration or complete resolution before the treatment, with no sequelae reported in the occipital region. DISCUSSION: The trigemino-cervical complex has the potential to cause neuralgia in the occipital region, as referred pain, caused by trigeminal herpes zoster. These cases suggest that, even if conjunctivitis or reddish spots appear to be trivial in the trigeminal nerve territory, trigeminal herpes zoster should be considered when neuralgia occurs in the ipsilateral occipital region.

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.

A surgical decision aid for occipital neuralgia with literature review and single center case series.

BACKGROUND: Occipital neuralgia (ON) is a debilitating headache disorder. Due to the rarity of this disorder and lack of high-level evidence, a clear framework for choosing the optimal surgical approach for medically refractory ON incorporating shared decision making with patients does not exist. METHODS: A literature review of studies reporting pain outcomes of patients who underwent surgical treatment for ON was performed, as well as a retrospective chart review of patients who underwent surgery for ON within our institution. RESULTS: Thirty-two articles met the inclusion criteria. A majority of the articles were retrospective case series (22/32). The mean number of patients across the studies was 34 (standard deviation (SD) 39). Among the 13 studies that reported change in pain score on 10-point scales, a study of 20 patients who had undergone C2 and/or C3 ganglionectomies reported the greatest reduction in pain intensity after surgery. The studies evaluating percutaneous ablative methods including radiofrequency ablation and cryoablation showed the smallest reduction in pain scores overall. At our institution from 2014 to 2023, 11 patients received surgical treatment for ON with a mean follow-up of 187 days (SD 426). CONCLUSION: Based on these results, the first decision aid for selecting a surgical approach to medically refractory ON is presented. The algorithm prioritizes nerve sparing followed by non-nerve sparing techniques with the incorporation of patient preference. Shared decision making is critical in the treatment of ON given the lack of clear scientific evidence regarding the superiority of a particular surgical method.

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.

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.

Debunking myths in headache diagnosis for the pain practitioner.

With headache being one of the most common chief complaints, it is essential for pain practitioners to interpret and differentiate a variety of headache characteristics to accurately diagnose and treat specific headache disorders. Certain misconceptions often lead to misdiagnosis. This article presents and discusses six myths about several common headache disorders (migraine, tension-type headache, cluster headache, cervicogenic headache, sinus headache, and occipital neuralgia) often encountered in clinical practice. The discussion is based primarily on the International Classification of Headache Disorders, 3rd edition and the latest studies. Recognizing and understanding the intricacies behind key headache diagnoses will help providers devise appropriate plans to better care for their patients.

Nerve blocks for occipital headaches: A systematic review and meta-analysis.

Migraine surgeons have identified six "trigger sites" where cranial nerve compression may trigger a migraine. This study investigates the change in headache severity and frequency following nerve block of the occipital trigger site. This PRISMA-compliant systematic review of five databases searched from database inception through May 2020 is registered under the PROSPERO ID: CRD42020199369. Only randomized controlled trials utilizing injection treatments for headaches with pain or tenderness in the occipital scalp were included. Pain severity was scored from 0 to 10. Headache frequency was reported as days per week. Included were 12 RCTs treating 586 patients of mean ages ranging from 33.7 to 55.8 years. Meta-analyses of pain severity comparing nerve blocks to baseline showed statistically significant reductions of 2.88 points at 5 to 20 min, 3.74 points at 1 to 6 weeks, and 1.07 points at 12 to 24 weeks. Meta-analyses of pain severity of nerve blocks compared with treatment groups of neurolysis, pulsed radiofrequency, and botulinum toxin type A showed similar headache pain severity at 1 to 2 weeks, and inferior improvements compared with the treatment groups after 2 weeks. Meta-analyses of headache frequency showed statistically significant reductions at 1 to 6-week follow-ups as compared with baseline and at 1 to 6 weeks as compared with inactive control injections. The severity and frequency of occipital headaches are reduced following occipital nerve blocks. This improvement is used to predict the success of migraine surgery. Future research should investigate spinous process injections with longer follow-up.

Surgical management of pediatric occipital neuralgia: a single-center experience of an uncommon pathology.

OBJECTIVE: Occipital neuralgia (ON) is a rare headache disorder characterized by sharp pain in the distribution of the greater occipital nerve (GON), lesser occipital nerve, or third occipital nerve. ON is commonly associated with traumatic injury, and effective identification and diagnosis can be difficult given the infrequent presentation and similarities to other pediatric headache disorders. While GON decompression has been well described in adults for refractory pain, there is a paucity of data in the pediatric population, with no previously published series on ON. The primary aim of this study was to identify the characteristics of pediatric patients with ON prior to surgical intervention and to describe the natural history of postoperative outcomes after decompression or neurectomy in a pediatric population. METHODS: A single-center retrospective case series was performed to evaluate factors predisposing children to refractory ON and the surgical efficacy of GON decompression or neurectomy. Six patients (mean age 15.0 ± 2.2 years) were identified for inclusion from October 2021 to October 2022. All patients had refractory ON as diagnosed by a pediatric neurologist. After medical therapy and repeated occipital nerve blocks failed, the patients were referred for GON decompression. Five patients had a history of trauma. RESULTS: Six patients were identified and treated in our cohort, highlighting the infrequency of this pathology. All had at least one occipital nerve block, with 83% receiving varied relief. All underwent bilateral decompression or neurectomy of the GON and experienced relief, reporting improved visual analog scale scores (mean 8.3 ± 0.9 preoperatively to 1.0 ± 2.2 postoperatively, p = 0.0009). The patients were followed for an average of 10 months, and their mean number of medications decreased from 2.7 ± 0.5 preoperatively to 0.8 ± 0.7 postoperatively (p = 0.019). Each patient reported numbness or tingling in the GON distribution postoperatively, which spontaneously resolved over time. Two patients had recurrent pain in a delayed fashion. CONCLUSIONS: GON decompression and neurectomy are efficacious treatments of refractory ON in the pediatric population.

The Occipital Nerves Applied Strain Test to Support Occipital Neuralgia Diagnosis.

INTRODUCTION: Occipital neuralgia (ON) is a disabling cephalalgia form with demanding diagnostic workflow. We report the description and reliability analyses of the occipital nerves-applied strain (ONAS) test for occipital neuralgia (ON) early-stage diagnosis in cephalalgia patients. METHODS: In a retrospective and observational study, we evaluated, among n = 163 consecutive cephalalgia patients, the sensitivity, specificity, and prior probability [positive (PPV) and negative (NPV) predictive values] of the ONAS test against two reference tests (occipital nerve anesthetic block and the painDETECT questionnaire). Multinomial logistic regression (MLR) and χ2 analyses verified the ONAS test outcome's dependence upon independent variables (gender, age, pain site, block test, and painDETECT outcomes). We assessed inter-rater agreement with Cohen's kappa statistic. RESULTS: ONAS test showed sensitivity and specificity of 81 and 18%, respectively, against the painDETECT and of 94 and 46%, respectively, against the block test. PPV was > 70% against both tests, while NPV was 81% against the block test and 26% against the painDETECT. Interrater agreement Cohen's kappa was excellent. Significant association (χ2 analyses) and relationship (MLR) were found only between ONAS test and pain site but not with the other independent predictors. CONCLUSIONS: The ONAS test showed satisfactory reliability among cephalalgia patients; thus, it might be considered a valuable early stage tool for ON diagnosis in these patients.

We report the description and reliability features of an occipital neuralgia diagnostic tool. The latter is based on the assertion that applying a strain on putatively compromised occipital nerves prompts abnormal nerve discharges and subjective pain reactions and thus may reveal occipital neuralgia. Among 163 cephalalgia patients, the test showed sensitivity and specificity of 81 and 18%, respectively, against the painDETECT questionnaire and 94 and 46%, respectively, against the occipital nerves' block test. Interrater agreement was excellent, and significant associations and relationships were found only between the tool and congruent pain site but not with the other independent predictors. This tool may help clinicians' early detection of occipital neuralgia in cephalalgia patients.

H7N9 avian influenza with first manifestation of occipital neuralgia: A case report.

BACKGROUND: Most of the first symptoms of avian influenza are respiratory symptoms, and cases with occipital neuralgia as the first manifestation are rarely reported. CASE SUMMARY: A middle-aged patient complaining of paroxysmal pain behind the ear was admitted to our hospital. The patient's condition changed rapidly, and high fever, unexpected respiratory failure, and multiple organ failure developed rapidly. The patient was diagnosed with H7N9 avian influenza based on etiology. CONCLUSION: We believe that the etiology of occipital neuralgia is complex and could be the earliest manifestation of severe diseases. The possibility of an infectious disease should be considered when occipital neuralgia is accompanied by fever. Avian influenza is one of these causative agents.

Tourette's Syndrome cervical dystonia induced occipital neuralgia remedied by peripheral nerve stimulation: A case report / Síndrome de Tourette, distonia cervical induzida por neuralgia occipital remediada por estimulação nervosa periférica: relato de caso

BACKGROUND: Dystonia is uncommon in Tourette's syndrome, and occipital neuralgia secondary to Tourette's dystonia is more rare, affecting quality of life. Occipital peripheral nerve stimulation (PNS) is an excellent alternative by being adjustable and minimally invasive. Our case demonstrates occipital PNS as an effective option for refractory Tourette's dystonia. CASE PRESENTATION: A thirty-four-year-old male with poorly controlled Tourette's cervical dystonia presented with severe occipital neuralgia. Various medications were prescribed including propranolol and amitriptyline, and bilateral third-occipital nerve rhizotomies and occipital nerve blocks were trialed. Distal nerve blocks at the occipital protuberance were most effective. Therefore, an occipital PNS trial was done, and a PNS was implanted with no complications. Upon follow-up, the patient reported drastic pain reduction. CONCLUSION: Our case illustrates neuromodulation benefits for a rare presentation of refractory occipital neuralgia secondary to Tourette's-related dystonia. Occipital PNS should be considered for refractory cases because it is safe, easy to implant, and effective.

FUNDAMENTO: A distonia é incomum na síndrome de Tourette, e a neuralgia occipital secundária à distonia de Tourette é mais rara, afetando a qualidade de vida. A estimulação do nervo periférico occipital (SNP) é uma excelente alternativa por ser ajustável e minimamente invasiva. Nosso caso demonstra o SNP occipital como uma opção eficaz para a distonia de Tourette refratária. APRESENTAÇÃO DO CASO: Um homem de 34 anos com distonia cervical de Tourette mal controlada apresentou neuralgia occipital grave. Vários medicamentos foram prescritos, incluindo propranolol e amitriptilina, e foram testadas rizotomias bilaterais do nervo terceiro-occipital e bloqueios do nervo occipital. Os bloqueios dos nervos distais na protuberância occipital foram mais eficazes. Portanto, foi feito um ensaio de PNS occipital e um PNS foi implantado sem complicações. Após o acompanhamento, o paciente relatou redução drástica da dor. CONCLUSÃO: Nosso caso ilustra os benefícios da neuromodulação para uma apresentação rara de neuralgia occipital refratária secundária à distonia relacionada a Tourette. O PNS occipital deve ser considerado para casos refratários porque é seguro, fácil de implantar e eficaz.

Narrative review of peripheral nerve blocks for the management of headache.

OBJECTIVE: To provide an overview of the current available literature on peripheral nerve blocks for the management of migraine and other headache disorders in adults. BACKGROUND: Peripheral nerve blocks have been commonly performed in the headache practice for migraine, cluster headache, occipital neuralgia, and other headache disorders, despite a paucity of evidence supporting their use historically. In the past decade, there has been an effort to explore the efficacy and safety of peripheral nerve blocks for the management of headache, with the greatest interest centered around greater occipital blocks. DESIGN: We performed a search in PubMed using key words including "occipital nerve blocks," "peripheral nerve blocks," "occipital nerve," "migraine," "cluster headache," and "neuralgia." We reviewed the randomized controlled trials (RCTs), observational studies, and case series, and summarized the anatomy, techniques, and the evidence for the use of peripheral nerve blocks in different headache disorders, with particular focus on available RCTs. Case reports were included for a detail review of adverse events. RESULTS: Of 12 RCTs examining the use of greater occipital nerve blocks for migraine, all but one demonstrate efficacy with reduction in headache frequency, intensity, and/or duration compared to placebo. Studies have not demonstrated a difference in clinical outcomes with the use of corticosteroids for nerve blocks compared to blocks with local anesthetic in the treatment of migraine. There are two RCTs supporting the use of greater occipital blockade for cluster headache, both showing benefit of suboccipitally injected corticosteroid. One RCT suggests benefit of greater occipital nerve blocks for cervicogenic headache. Observational studies and case series/reports show that greater occipital nerve block may be effective in prolonged migraine aura, status migrainosus, post-dural puncture headache, and occipital neuralgia. Overall, peripheral nerve blocks are well tolerated. Serious side effects are rare but have been reported, including acute cerebellar syndrome and infection. CONCLUSIONS: Peripheral nerve blocks, especially occipital nerve blocks, are a viable treatment option for migraine and may be helpful in cluster headache as a transitional therapy or rescue therapy. Additional prospective studies are needed to investigate the efficacy and safety of occipital nerve blocks for long-term migraine prevention, as well as for other headache disorders, such as occipital neuralgia.

Surgical therapy of occipital (Arnold) neuralgia: A case series.

Objective: The idea to treat occipital neuralgia patients with a surgical procedure is relatively recent. The aim of this paper was to describe the surgical techniques and our 12-year experience in this field. Materials and methods: From June 2011 till February 2022 we have performed surgery over 232 patients with occipital neuralgia. Results: The surgical procedure elicited a positive response in 86% of the patients. Conclusions: The described techniques allowed to obtain an high rate of positive results with a minimum percentage of complications.

Occipital Neuralgia following Acoustic Neuroma Resection.

Background While postoperative outcomes of acoustic neuroma (AN) resection commonly consider hearing preservation and facial function, headache is a critical quality of life factor. Postoperative headache is described in the literature; however, there is limited discussion specific to occipital neuralgia (ON) following AN resection. Objective The aim of this study is to investigate the effectiveness of conservative management and surgery. Methods We conducted a retrospective review of 872 AN patients who underwent resection at our institution between 1988 and 2017 and identified 15 patients (1.9%) that met International Classification of Headache Disorders criteria for ON. Results Of the 15 ON patients, surgical approaches included 13 (87%) retrosigmoid (RS), one (7%) translabyrinthine (TL), and one (7%) combined RS + TL. Mean clinical follow-up was 119 months (11-263). Six (40%) patients obtained pain relief through conservative management, while the remaining nine (60%) underwent surgery or ablative procedure. Three (38%) patients received an external neurolysis, four (50%) received a neurectomy, one (13%) had both procedures, and one (13%) received two C2 to 3 radio frequency ablations. Of the nine patients who underwent procedural ON treatment, seven (78%) patients achieved pain relief, one patient (11%) continued to have pain, and one patient (11%) was lost to follow-up. Of the six patients whose pain was controlled with conservative management and nerve blocks, five (83%) found relief by using neuropathic pain medication and one (17%) found relief on nonsteroidal anti-inflammatory drug. Conclusion Our series demonstrates success with conservative management in some, but overall a minority (40%) of patients, reserving decompression only for refractory cases.

Trigeminal Herpes Zoster Transited to Ipsilateral Occipital Neuralgia.

The pain of occipital neuralgia (ON) is thought to be secondary to trauma or injury to the occipital nerve at any point along the course of the nerve. ON may also be caused by an infectious process (herpes zoster) or compression of the nerve. The patient, in this case, presented to our clinic with complaints of occipital pain and rash and swelling of the right lower jaw. One week before presenting to our clinic, the patient developed severe pain in the first division of the trigeminal region with erythema and vesicles. A blood test showed a remarkably high antibody titer for varicella-zoster virus (VZV). The patient was prescribed oral valacyclovir (Valtrex®) (3000 mg/day), which resulted in the complete remission of the rash and blisters in the occipital region. This highlights the importance of considering neuroanatomy of the trigeminal region and cervical nerve.

Intrathecal Morphine Infusion for Trigeminal Deafferentation Pain Following Percutaneous Intervention for Unexplained Facial Pain: A Case Report.

Chronic pain in painful post-traumatic trigeminal neuropathy, formerly called trigeminal deafferentation pain (TDP) or anesthesia dolorosa, is virtually incurable neuropathic pain. In severe cases, no effective method has yet been established. A 58-year-old woman presented with chronic dysesthetic pain in the right side of her face that had persisted for 8 years. It was caused by percutaneous balloon compression for an unexplained, persistent right gingival pain. The TDP did not respond to any medications or radiosurgery. Considering the typical occipital neuralgia that occurred later, the incomprehensible gum pain was interpreted as referred trigeminal pain from occipital neuralgia. Decompression of the greater occipital nerve improved occipital neuralgia; however, TDP did not respond to internal neurolysis or invasive brain stimulation. The last attempt was made to administer an intrathecal opioid because of pain sufficiently severe to cause suicidal ideation. Trial administration of intrathecal opioids had some effect on pain relief. Although incomplete, the effects of intrathecal morphine infusion were maintained up to 1 year later. Invasive neurosurgical interventions should be cautiously performed for continuous pain in persistent idiopathic facial pain and referred facial pain cases that do not show typical neuralgic pain in primary trigeminal neuralgia because of the risk of TDP.

Anatomy of the greater occipital nerve: implications in posterior fossa approaches.

PURPOSE: Because of its superficial location in the dorsal regions of the scalp, the greater occipital nerve (GON) can be injured during neurosurgical procedures, resulting in post-operative pain and postural disturbances. The aim of this work is to specify the course of the GON and how its injuries can be avoided while performing posterior fossa approaches. METHODS: This study was carried out at the department of anatomy at Bordeaux University. 4 specimens were dissected to study the GON course. Posterior fossa approaches (midline suboccipital, paramedian suboccipital, retrosigmoid and petrosal) were performed on 4 other specimens to assess potential risks of GON injuries. RESULTS: The GON runs around the obliquus capitis inferior (100%), crosses the semispinalis capitis (100%) and the trapezius (75%) or its aponeurosis (25%). Direct GON injuries can be seen in paramedian suboccipital approaches. Stretching of the GON can occur in midline suboccipital and paramedian suboccipital approaches. We found no evidence of direct or indirect GON injury in retrosigmoid or petrosal approaches. CONCLUSION: Our study provides interesting data regarding the risk GON injury in posterior fossa approaches. Direct GON injuries in paramedian suboccipital approaches can be avoided with careful dissection. Placing retractors in contact with the periosteum and performing a minimal retraction may help to avoid excessive GON stretching in midline suboccipital and paramedian suboccipital approaches. Furthermore, the incision for retrosigmoid approaches should be as lateral as possible and not too caudal. Finally, avoiding extreme patient positioning reduces the risk of GON stretching in all approaches.