Microsurgical Anatomy of the Hypoglossal and C1 Nerves: Description of a Previously Undescribed Branch to the Atlanto-Occipital Joint.

OBJECTIVE: Distal branches of the C1 nerve that travel with the hypoglossal nerve have been well investigated but relationships of C1 and the hypoglossal nerve near the skull base have not been described in detail. Therefore, the aim of this study was to investigate these small branches of the hypoglossal and first cervical nerves by anatomic dissection. METHODS: Twelve sides from 6 cadaveric specimens were used in this study. To elucidate the relationship among the hypoglossal, vagus, and first and cervical nerve, the mandible was removed and these nerves were dissected under the surgical microscope. RESULTS: A small branch was found to always arise from the dorsal aspect of the hypoglossal nerve at the level of the transverse process of the atlas and joined small branches from the first and second cervical nerves. The hypoglossal and C1 nerves formed a nerve plexus, which gave rise to branches to the rectus capitis anterior and rectus capitis lateralis muscles and the atlanto-occipital joint. CONCLUSIONS: Improved knowledge of such articular branches might aid in the diagnosis and treatment of patients with pain derived from the atlanto-occipital joint. We believe this to be the first description of a branch of the hypoglossal nerve being involved in the innervation of this joint.

Upper cervical facet joint and spinal rami blocks for the treatment of cervicogenic headache.

OBJECTIVE: To evaluate the efficacy of upper cervical facet joint injections and spinal rami blocks in the treatment of cervicogenic headache. BACKGROUND: Cervicogenic headache has been recognized as a common and often disabling disorder. The treatment of this headache type remains challenging. METHODS: We conducted a retrospective chart review of 31 patients with refractory cervicogenic headache who underwent fluoroscopically guided C(1/2), C(2/3) facet joint injections and C(2), C(3) spinal rami blocks using a mixture of 0.25% bupivacaine and 3 mg betamehtasone. The outcome measures were the change in headache severity, assessed using an 11-point numerical pain scale, after treatment, and the duration of head pain relief. RESULTS: Twenty-eight (90.3%) patients experienced >50% headache relief after treatment, with an average duration of 21.7 (1-90) days. Mean (+/-SD) head pain intensity decreased from 7.5 +/- 1.3 before treatment to 2.7 +/- 1.9 immediately after it (P < .0001). The procedures were well tolerated. CONCLUSIONS: C(1/2), C(2/3) facet joint injections and C(2), C(3) spinal rami blocks were effective and well tolerated for the treatment of cervicogenic headache in this study. The procedures provided significant and prolonged pain relief in the majority of patients. Larger controlled studies are needed to further evaluate the efficacy of this treatment modality in cervicogenic headache.

Estudio Ultrasonográfico de las Estructuras Nerviosas del Canal Vertebral a Nivel de la Articulación Atlantooccipital en Caninos Adultos / Ultrasonographic Study of the Nervous Structures of the Vertebral Canal at the Atlantooccipital Joint Level in Adult Dogs

Los objetivos de este estudio fueron describir y comparar, mediante el ultrasonido, las estructuras nerviosas que se encuentran en el canal vertebral a nivel de la articulación atlanto-occipital en caninos adultos de talla corporal pequeña y grande. Se utilizaron 20 caninos adultos clínicamente sanos: 10 caninos de talla corporal pequeña (peso < a 10 kg) y 10 a caninos de talla corporal grande (peso > a 20 kg). Se realizó el examen ultrasonográfico con un transductor de 7,5 MHz, utilizando para ello el espacio atlantooccipital como ventana ecográfica. Se midieron diámetros verticales y horizontales del saco dural y médula espinal, y áreas del saco dural, médula espinal y espacio subaracnoídeo. Se calcularon razones entre algunas mediciones. Las estructuras estudiadas se observaron ecográficamente de modo similar en los caninos de ambos grupos. La duramadre se observó como una línea hiperecoica continua, adherida al borde óseo del canal vertebral. La médula espinal se observó como una estructura ovalada hipoecoica, con un parénquima homogéneo. Los diámetros verticales y horizontales del saco dural, médula espinal y las áreas del saco dural, médula espinal y espacio subaracnoídeo fueron significativamente menores (p<0,05) en los caninos de talla corporal pequeña. Las diferencias entre las áreas de médula espinal entre los grupos fue menor a 0,1 cm² y entre las áreas de saco dural y espacio subaracnoídeo fue de aproximadamente 1 cm². Se concluye que el ultrasonido permite visualizar adecuadamente la médula espinal y estructuras asociadas en la región de la articulación atlanto-occipital en caninos adultos. Finalmente, existieron diferencias mínimas en los valores de áreas de médula espinal y notoriamente mayores en los valores de áreas del saco dural y espacio subaracnoídeo entre ambos grupos de animales.

The goals of this study were to describe and compare by ultrasound the nervous structures in the vertebral canal at the atlanto-occipital joint region in small and large size adult dogs. A total of 20 healthy adult dogs were selected for the study. They were 10 small dogs (< 10 kg) and 10 large dogs (> 20 kg). Ultrasonographic examination was performed with a 7,5 MHz transducer and using the atlanto-occipital space as an echographic window. In transverse images, vertical and horizontal diameters of the dural sac and spinal cord and areas of the dural sac, spinal cord and subarachnoid space were measured. Some ratios between measurements were also calculated. Analysed structures were observed in a similar way in both groups of dogs. The dura mater was observed as an echogenic continuous line and attached to the bony border. The subarachnoid space has an anechoic appearance. The pia mater was observed as a thin echogenic line covering the spinal cord surface. The spinal cord was observed as an oval hypoechogenic structure inside the vertebral canal and with a homogeneous parenchyma without differentiation between gray and white matter. Vertical and horizontal diameters of the dural sac and spinal cord and areas of the dural sac, spinal cord and subarachnoid space were significantly different (P<0,05) in both group of dogs. Differences of spinal cord areas between small and large dogs were minimal (<0,1 cm²), compared with differences between dural sac and subarachnoid space areas (around 1 cm x). In conclusion, ultrasound allows an adequate examination of spinal cord and associated structures at the atlanto-occipital joint region in adult dogs. Differences between groups are minor in areas of spinal cord and larger in areas of dural sac and subarachnoid space.

Role of the C2 articular branches in occipital headache: an anatomical study.

One of the most important structures involved in the pathogenesis of occipital headache is the lateral atlanto-axial joint. Previous studies demonstrated that injection of this joint with local anesthetic can alleviate occipital headache, while injection of contrast medium exacerbates it. The aim of our study is to improve the understanding of the nerve supply to the lateral atlanto-axial joint by the C2 nerve elements, in order to determine the optimal target for an anesthetic block of this area. Ten C2 spinal nerves and roots were dissected in five embalmed cadavers with the aid of a 40X microscope and the lateral atlanto-axial joint was shown to be extensively supplied by articular branches of C2 nerve elements (dorsal ganglion, spinal nerve, and ventral ramus). Following our observations on their distribution, we propose a target for local anesthetic injection of the C2 articular branches that is based on reliable landmarks and is easily identifiable at fluoroscopy. We suggest that local anesthetic injection at this target point could be of benefit in the relief of occipital pain due to cervical trauma or degenerative disease involving the lateral atlanto-axial joint.

Cervicogenic headache: interventional, anesthetic, and ablative treatment.

Cervicogenic headache is becoming an accepted clinical syndrome in which headache pain is thought to originate from the cervical spine. Unfortunately, there are no diagnostic imaging techniques of the cervical spine and associated structures that can determine the exact source of pain. Therefore, diagnosis and treatment are based on the major accepted criteria of clinical presentation and the use of diagnostic nerve blocks to identify the source of the pain generator before considering further interventional or neuroablative treatment. This suggests that consistent reproducible anatomic and neurophysiologic pathways exist for the reproduction of typical clinical pain patterns and the ability of neuroblockade to consistently interrupt these pain pathways. This article describes the essential anatomy required to understand the use of diagnostic nerve blocks, and their predictive value in anticipating response to neuroablative and interventional therapy with a review of the major interventional, anesthetic, and ablative techniques for cervicogenic headache.

Atlanto-occipital joint pain. A report of three cases and description of an intraarticular joint block technique.

BACKGROUND AND OBJECTIVES: The atlanto-occipital (AO) joint is a true, innervated synovial joint with the potential to cause pain. METHODS: A detailed description of an AO joint injection technique is provided, as none was found on review of the literature. RESULTS: Using this technique, three illustrative cases provide preliminary evidence that intraarticular injection of the AO joint may have both diagnostic and therapeutic value for the treatment of upper cervical pain and headaches. CONCLUSIONS: Although AO joint injections may prove to be an effective adjunct to more traditional forms of conservative treatment, additional prospective studies are needed to better define the role of intraarticular AO joint injections in the diagnosis and treatment of head and neck pain.

Atlanto-occipital and lateral atlanto-axial joint pain patterns.

STUDY DESIGN: Five asymptomatic subjects underwent provocative injections of the lateral atlanto-axial and atlanto-occipital joints. OBJECTIVES: This study isolated and stimulated the lateral atlanto-axial and atlanto-occipital joints via fluoroscopically guided intra-articular injections to determine if they are potential pain generators. If they are pain generators, preliminary pain pattern maps will be constructed. SUMMARY OF BACKGROUND DATA: The cervical zygapophyseal joints (C2-3 to C6-7) are potential pain generators as demonstrated by referred pain induced via isolated intra-articular joint injections in normal subjects. Tentative referral patterns based on direct mechanical stimulation of the lateral atlanto-axial and atlanto-occipital joints have not been reported. METHODS: Five volunteers without histories of upper cervical pain underwent two joint injections each. In all five subjects, the left atlanto-occipital and right lateral atlanto-axial joints were stimulated via injection of contrast medium causing distension of the joint capsule. RESULTS: Referred pain was produced with all ten injections. The lateral atlanto-axial injections resulted in consistent referral patterns, whereas the atlanto-occipital referral patterns varied significantly. A tentative composite diagram of the experimentally induced pain was created for each joint. CONCLUSION: This study confirms the nociceptive ability of these cervical synovial joints. This study may assist the clinician in the differential diagnosis of head and neck pain.

[Earache and functional disorders of the cervical spine]. / Ohrschmerz und Funktionsstörungen der Halswirbelsäule.

The importance of the cervical spine in routine ENT practice is discussed, using the example of otalgia due to disorders of the cervical vertebra: Evaluation and follow-ups of 13,000 patients showed that 6% had diseases caused by the cervical spine. Frequency, pathophysiology and treatment results of cervicogenic otalgia are presented. The principles of adequate functional diagnostics and therapy of cervical spine disorders are explained.

[Characteristics of the topographical anatomical interrelations of the vertebral artery, muscles and connective tissue and neural formations in the area of the atlanto-occipital joint]. / Osobennosti topografoanatomicheskikh vzaimootnoshenii pozvonochnoi arterii, myshts, soedinitel'notkannykh i nervnykh obvazovanii v oblasti atlantozatylochnogo sustava.

A topographical-anatomical investigation has been performed in the atlanto-occipital joint area by means of Pirogov's saw cuts and the histopographic section technique in 28 corpses of fetuses, newborns and mature persons. Peculiarities of interrelations between the vertebral artery, veins, muscles, nerves and the joint elements have been considered at the level of three horizontal and two sagittal planes made in the joint area. The vertebral artery and its venous plexus have been demonstrated to go in the nearest vicinity to the joint, the veins adhere the joint, and the common fascial vascular sheath entwines in the joint capsule. The proper occipital muscles situating here: the superior and inferior oblique muscles and the musculus rectus capitis posterior major press these vessels, as well as the anterior and posterior branches of the first cervical nerve, to the joint. These tight relations of the muscles, vertebral vessels and branches of the first cervical nerve create conditions for compression of the neuro-vascular formations in the atlanto-occipital joint area.