The effectiveness and safety of cranial nerve block in migraine: a critical review / A eficácia e segurança do bloqueio de nervos cranianos na enxaqueca: uma revisão crítica

Cranial nerve blocks (CNBs) have been used for the acute and preventive treatment of a variety of headaches, including migraine. The effectiveness of CNBs in migraine is usually observed beyond the duration of the nerve block, possibly due to central pain modulation. The most used target is the greater occipital nerve. Other commonly targeted nerves are the lesser occipital nerve and various branches of the trigeminal nerve, including the supratrochlear, supraorbital, and auriculotemporal nerves. CNBs are generally safe and well-tolerated procedures that can be performed in either emergency or outpatient settings. There is currently no guideline standardizing CNBs in migraine. In clinical practice, as well as the few published studies, the results are encouraging, justifying further studies in the area. In the present study we critically review the literature about the safety and efficacy of CNBs in the treatment of migraine attacks and in the preventive treatment of migraine.

Bloqueios de nervos cranianos (BNCs) têm sido usados ​​para o tratamento agudo e preventivo de uma variedade de dores de cabeça, incluindo enxaqueca. A eficácia dos BNC na enxaqueca é geralmente observada além da duração do bloqueio nervoso, possivelmente devido à modulação central da dor. O alvo mais utilizado é o nervo occipital maior. Outros nervos comumente alvo são o nervo occipital menor e vários ramos do nervo trigêmeo, incluindo os nervos supratroclear, supraorbital e auriculotemporal. Os CNBs são geralmente procedimentos seguros e bem tolerados que podem ser realizados em ambientes de emergência ou ambulatoriais. Atualmente não há nenhuma diretriz padronizando BNCs na enxaqueca. Na prática clínica, assim como nos poucos estudos publicados, os resultados são animadores, justificando novos estudos na área. No presente estudo revisamos criticamente a literatura sobre a segurança e eficácia dos BNC no tratamento de crises de enxaqueca e no tratamento preventivo da enxaqueca.

Dissection and observation of a large unnamed nerve in the posterior cervical triangle / 南方医科大学学报

<p><b>OBJECTIVE</b>To characterize the anatomical features of a large unnamed nerve in the posterior cervical triangle and clarify its relationship with the lesser occipital nerve.</p><p><b>METHODS</b>We dissected 31 adult formalin-fixed cadaver head and neck specimens (62 sides). The lateral cervical region, the anterior cervical region, the sternocleidomastoid region, and the occipital region were dissected to define the anatomical features of the unnamed nerve.</p><p><b>RESULTS</b>This unnamed nerve was identified in the posterior cervical triangle in 96.8% of the specimens. The main trunk of the nerve had a diameter of about 3 mm with a length of around 10 cm. The nerve arose from the anterior branch of the second cervical nerve (C2, C2-3), entered the posterior cervical triangle at 1-3 cm above the accessory nerve, and continued to ascend along or in parallel with the posterior border of the sternocleidomastoid muscle. It passed between the attachments of the sternocleidomastoid and the trapezius to the occiput and divided into 3-5 branches, which innervated the skin area between the lesser and greater occipital nerves.</p><p><b>CONCLUSIONS</b>We identified a large unnamed nerve in the posterior cervical triangle, for which we coined the name "long occipital nerve" based on its unique anatomical features. The discovery of this nerve can be important for local surgery and for diagnosis and treatment of related diseases.</p>

Neuralgias of the Head: Occipital Neuralgia

Occipital neuralgia is defined by the International Headache Society as paroxysmal shooting or stabbing pain in the dermatomes of the greater or lesser occipital nerve. Various treatment methods exist, from medical treatment to open surgical procedures. Local injection with corticosteroid can improve symptoms, though generally only temporarily. More invasive procedures can be considered for cases that do not respond adequately to medical therapies or repeated injections. Radiofrequency lesioning of the greater occipital nerve can relieve symptoms, but there is a tendency for the pain to recur during follow-up. There also remains a substantial group of intractable patients that do not benefit from local injections and conventional procedures. Moreover, treatment of occipital neuralgia is sometimes challenging. More invasive procedures, such as C2 gangliotomy, C2 ganglionectomy, C2 to C3 rhizotomy, C2 to C3 root decompression, neurectomy, and neurolysis with or without sectioning of the inferior oblique muscle, are now rarely performed for medically refractory patients. Recently, a few reports have described positive results following peripheral nerve stimulation of the greater or lesser occipital nerve. Although this procedure is less invasive, the significance of the results is hampered by the small sample size and the lack of long-term data. Clinicians should always remember that destructive procedures carry grave risks: once an anatomic structure is destroyed, it cannot be easily recovered, if at all, and with any destructive procedure there is always the risk of the development of painful neuroma or causalgia, conditions that may be even harder to control than the original complaint.

Sensory Complications in Patients after Scalp Mass Excision and Its Anatomical Considerations

OBJECTIVE: To evaluate the incidence of postsurgical sensory complications in patients with scalp masses and classify the locations of them from a surgical standpoint according to anatomical considerations. METHODS: A total of 121 patients who underwent surgery for scalp mass were included in this study. The authors reviewed medical records and preoperative radiologic images. We investigated the complications related to sensory changes after procedure. Enrolled patients have been divided into three groups. Group A included patients with tumors above the superior nuchal line (SNL), Group B with tumors within the trapezius muscle area and patients who had tumors on the lateral trapezius muscle area were assigned to Group C. We compared the incidence related to postoperative sensory complications and summarized their additional treatments for these with clinical outcome. RESULTS: There were 12 patients (10%) with sensory complications related on the mass excision site (Group A: 1 patient, Group B: 2 patients, Group C: 9 patients). Six patients were affected with lesser occipital nerve (LON), 2 patients on greater occipital nerve (GON) and 4 patients on GON and LON. Over 6 months after surgery, two of the twelve patients with sensory complications did not have complete recovered pain in spite of proper medications and local chemical neurolysis with 1.0% lidocaine and dexamethasone. CONCLUSION: Occipital neuropathy should be considered as a complication related excision of scalp mass. The sensory complications are more frequent in Group C because of the anatomical characteristics of the occipital nerves and there were no statistical difference for other variables.

The lesser occipital nerve in fetuses / El nervio occipital menor en fetos

The lesser occipital nerve (LON) is an ascending superficial branch of the cervical plexus that has a variable origin either from the ventral ramus of the second cervical nerve or second and third cervical nerves and is purely sensory. Forty fetuses (right side: 40/80; left: 40/80) with gestational ages between 15 to 28 weeks were microdissected to document the anatomy of the LON. Results: a) Incidence and Morphometry: LON present in 100 percent specimens, with average length on the right and left sides of 23.59 +/- 2.32 mm and 23.45 +/- 2.27 mm, respectively; b) Course: In its ascent towards the occipital region, the LON was located on the splenius capitus muscle in 85 percent of specimens and in 15 percent of the specimens, it ascended vertically on the sternocleidomastoid muscle towards the ear, innervating its superior third; c) Branching pattern: LON displayed (i) single: 70 percent; (ii) duplicate: 26 percent and (iii) triplicate: 4 percent patterns; d) Variation in the course of LON was observed in 6 percent of the specimens. Knowledge of the anatomy and variations of the LON may assist in the understanding of cervicogenic headaches and may be of assistance to anesthetists performing regional anesthesia for surgical procedures in the neck.

El nervio occipital menor (NOM) es una rama ascendente superficial del plexo cervical que tiene un origen variable ya sea del ramo ventral del segundo nervio cervical o de los nervios cervicales segundo y tercero, y es solamente sensitivo. Cuarenta fetos (lado derecho: 40/80; izquierdo: 40/80), con edades gestacionales de 15 a 28 semanas fueron microdisecados para documentar la anatomía del NOM. a) Incidencia y morfometría: el NOM estuvo presente en el 100 por ciento de los especímenes, con una longitud media de los lados derecho e izquierdo de 23,59 +/- 2,32 mm y 23,45 +/- 2,27 mm, respectivamente; b) Curso: en su ascenso hacia la región occipital, el NOM se localiza en el músculo esplenio de la cabeza en el 85 por ciento de las muestras y en el 15 por ciento de las muestras, ascendió verticalmente sobre el músculo esternocleidomastoideo hacia el oído, inervando el tercio superior, c) Patrón de ramificación: el NOM se observa (i) individual: 70 por ciento, (ii) duplicado: 26 por ciento y (iii) triplicado: 4 por ciento de los patrones; d) Variación en el curso de NOM se observó en el 6 por ciento de las muestras. El conocimiento de la anatomía y las variaciones del NOM puede ayudar en la comprensión de los dolores de cabeza cervical y puede ser de ayuda a los anestesiólogos a realizar la anestesia regional para procedimientos quirúrgicos en el cuello.