Congenital atlanto-occipital fusion and its effect on the myodural bridge: a case report utilizing the P45 plastination technique / Fusión atlanto-occipital congénita y su efecto sobre el puente miodural: reporte de un caso utilizando la técnica de plastinación P45

SUMMARY: The atlanto-occipital joint is composed of the superior fossa of the lateral masses of the atlas (C1) and the occipital condyles. Congenital Atlanto-occipital fusion (AOF) involves the osseous union of the base of the occiput (C0) and the atlas (C1). AOF or atlas occipitalization/assimilation represents a craniovertebral junction malformation (CVJM) which can be accompanied by other cranial or spinal malformations. AOF may be asymptomatic or patients may experience symptoms from neural compression as well as limited neck movement. The myodural bridge (MDB) complex is a dense fibrous structure that connects the suboccipital muscular and its related facia to the cervical spinal dura mater, passing through both the posterior atlanto-occipital and atlanto-axial interspaces. It is not known if atlas occipitilization can induce structural changes in the MDB complex and its associated suboccipital musculature. The suboccipital region of a cadaveric head and neck specimen from an 87-year-old Chinese male having a congenital AOF malformation with resultant changes to the MDB complex was observed. After being treated with the P45 plastination method, multiple slices obtained from the cadaveric head and neck specimen were examined with special attention paid to the suboccipital region and the CVJM. Congenital atlanto-occipital fusion malformations are defined as partial or complete fusion of the base of the occiput (C0) with the atlas (C1). In the present case of CVJM, unilateral fusion of the left occipital condyle with the left lateral mass of C1 was observed, as well as posterior central fusion of the posterior margin of the foramen magnum with the posterior arch of C1. Also noted was a unilateral variation of the course of the vertebral artery due to the narrowed posterior atlanto-occipital interspace. Surprisingly, complete agenesis of the rectus capitis posterior minor (RCPmi) and the obliques capitis superior (OCS) muscles was also observed in the plastinated slices. Interestingly, the MDB, which normally originates in part from the RCPmi muscle, was observed to originate from a superior bifurcation within an aspect of the nuchal ligament. Therefore, the observed changes involving the MDB complex appear to be an effective compensation to the suboccipital malformations.

RESUMEN: La articulación atlanto-occipital está compuesta por las caras articulares superiores de las masas laterales del atlas (C1) y los cóndilos occipitales. La fusión atlanto-occipital congénita (FAO) implica la unión ósea de la base del occipucio (C0) y el atlas (C1). La FAO u occipitalización/asimilación del atlas representa una malformación de la unión craneovertebral (MUCV) que puede presentar otras malformaciones craneales o espinales. La FAO puede ser asintomática o los pacientes pueden experimentar síntomas de compresión neural así como movimiento limitado del cuello. El complejo del puente miodural (PMD) es una estructura fibrosa densa que conecta el músculo suboccipital y su fascia relacionada con la duramadre espinal cervical, pasando a través de los espacios intermedios atlanto-occipital posterior y atlanto-axial. No se sabe si la occipitilización del atlas puede inducir cambios estructurales en el complejo PMD y en la musculatura suboccipital. Se observó en la región suboccipital de un espécimen cadavérico, cabeza y cuello de un varón chino de 87 años con una malformación congénita de FAO con los cambios resultantes en el complejo PMD. Se examinaron múltiples cortes obtenidos de la muestra de cabeza y cuello después de ser tratados con el método de plastinación P45, con especial atención a la región suboccipital y la MUCV. Las malformaciones congénitas por fusión atlanto-occipital se definen como la fusión parcial o completa de la base del occipucio (C0) con el atlas (C1). En el presente caso de MUCV se observó la fusión unilateral del cóndilo occipital izquierdo con la masa lateral izquierda de C1, así como fusión posterior central del margen posterior del foramen magnum con el arco posterior de C1. También se observó una variación unilateral del curso de la arteria vertebral por el estrechamiento del espacio interatlanto-occipital posterior. Se observó además agenesia completa de los músculos Rectus capitis posterior minor (RCPmi) y oblicuos capitis superior (OCS) en los cortes plastinados. Curiosamente, se observó que el MDB, que normalmente se origina en parte del músculo RCPmi, se origina en una bifurcación superior dentro de un aspecto del ligamento nucal. Por lo tanto, los cambios observados en el complejo PMD parecen ser una compensación de las malformaciones suboccipitales.

Asociación de los grados de movilidad de la articulación atlanto-occipital con la clasificación de Cormack- Lehane como predictores de una vía aérea pediátrica difícil en pacientes de 0 a 12 años de edad en el Hospital Municipal Boliviano Holandés, 2017 / Association of the degrees of mobility of the atlanto-occipital joint with the Cormack-Lehane classification as predictors of a difficult pediatric airway in patients aged 0 to 12 years at the" Municipal Boliviano Holandés" Hospital, 2017

OBJETIVO. Determinar la asociación que existe entre las valoraciones de la articulación atlantooccipital durante la valoración preanestésica y la valoración del Cormack Lehane durante la intubación para predecir una vía aérea difícil en el paciente pediátrico de 0 a 12 años de edad que ingresaron a quirófano del Hospital Municipal Boliviano Holandés en los meses de agosto a octubre de la Gestión 2017. MATERIAL Y METODOS. Es un diseño observacional descriptivo de corte transversal, en 70 pacientes de 0 a 12 años de edad que siguiendo criterios estrictos de inclusión se evaluó la clasificación de vía aérea difícil pediátrica analizando la concordancia entre la asociación de la valoración de la articulación atlantooccipital con la escala de Cormack-Lehane. RESULTADOS. Se evaluaron pacientes entre 0 a 12 años, la Escala de Bellhouse Dore encontrada fue Grado I 39%, Grado III 29%, Grado II 24% y Grado IV 8% y el Cormack Lehane encontrado es grado I 39%, grado III 29%, grado II 24% y el grado IV 8%. La asociación de ambas escalas determinó como predictor de vía aérea normal al 63%, potencialmente difícil 29% y vía aérea difícil 8%. CONCLUSIÓN. Existe asociación entre las valoraciones de la articulación atlantooccipital durante la valoración preanestesica y la valoración del Cormack Lehane durante la intubación como predictor de una vía aérea difícil en el paciente pediátrico de 0 a 12 años de edad.

OBJECTIVE. To determine the association that exists between the assessments of the atlanto-occipital joint during the preanesthetic assessment and the assessment of the Cormack Lehane during intubation to predict a difficult airway in pediatric patients aged 0 to 12 who were admitted to the Municipal Boliviano Holandés Hospital in the months of August to October of the Management 2017. MATERIAL AND METHODS. It is an observational descriptive crosssectional design, in 70 patients from 0 to 12 years of age who, following strict inclusion criteria, evaluated the classification of pediatric difficult airway, analyzing the concordance between the association of the atlanto-occipital joint assessment with the Cormack-Lehane scale. RESULTS. Patients between 0 to 12 years old were evaluated, the Bellhouse Dore Scale found was Grade I 39%, Grade III 29%, Grade II 24% and Grade IV 8% and the Cormack Lehane found is grade I 39%, grade III 29 %, grade II 24% and grade IV 8%. The association of both scales determined a 63% normal airway as a predictor, 29% potentially difficult and 8% difficult airway. CONCLUSION. There is an association between the assessments of the atlanto-occipital joint during the pre-anesthetic assessment and the assessment of the Cormack Lehane during intubation as a predictor of a difficult airway in pediatric patients 0 to 12 years of age.

Late Subaxial Lesion after Overcorrected Occipitocervical Reconstruction in Patients with Rheumatoid Arthritis

STUDY DESIGN: Retrospective case-control study, level 4. PURPOSE: To clarify the risk factors for late subaxial lesion after occipitocervical (O-C) reconstruction. We examined cases requiring fusion-segment-extended (FE) reconstruction in addition to/after O-C reconstruction. OVERVIEW OF LITERATURE: Patients with rheumatoid arthritis (RA) frequently require O-C reconstruction surgery for cranio-cervical lesions. Acceptable outcomes are achieved via indirect decompression using cervical pedicle screws and occipital plate–rod systems. However, late subaxial lesions may develop occasionally following O-C reconstruction. METHODS: O-C reconstruction using cervical pedicle screws and occipital plate–rod systems was performed between 1994 and 2007 in 113 patients with RA. Occipito-atlanto-axial (O-C2) reconstruction was performed for 89 patients, and occipito-subaxial cervical (O-under C2) reconstruction was performed for 24 patients. We reviewed the cases of patients requiring FE reconstruction (fusion extended group, FEG) and 26 consecutive patients who did not require FE reconstruction after a follow-up of >5 years (non-fusion extended group, NEG) as controls. RESULTS: FE reconstructions were performed for nine patients at an average of 45 months (range, 24–180 months) after O-C reconstruction. Of the 89 patients, three (3%) underwent FE reconstruction in cases of O-C2 reconstruction. Of the 24 patients, five (21%) underwent FE reconstruction in cases of O-under C2 reconstruction (p=0.003, Fisher exact test). Age, sex, RA type, and neurological impairment stage were not significantly different between FEG and NEG. O-under C2 reconstruction, larger correction angle (4° per number of unfixed segment), and O-C7 angle change after O-C reconstruction were the risk factors for late subaxial lesions on radiographic assessment. CONCLUSIONS: Overcorrection of angle at fusion segments requiring O-C7 angle change was a risk factor for late subaxial lesion in patients with RA with fragile bones and joints. Correction should be limited, considering the residual mobility of the cervical unfixed segments.

Atlanto-Occipital Dislocation: A Case Report / 대한신경손상학회지

Patients with atlanto-occipital dislocation (AOD) are increasingly being transported to emergency rooms, alive, by the improved pre-hospital emergency rescue system. The author reports a fatal case of AOD with severe neurovascular injuries following a high-speed pedestrian collision. Therefore, nowadays, neurosurgeons can expect an increase in the occurrence of such cases; an early diagnosis and prompt occipitocervical fusion can save lives. This report reviews the current concepts of AOD in mild to fatal conditions.

Anatomic Considerations of Anterior Transarticular Screw Fixation for Atlantoaxial Instability

STUDY DESIGN: Cadaveric, observational study.PURPOSE: Atlantoaxial instability (AAI) is characterized by excessive movement at the C1–C2 junction between the atlas and axis. An anterior surgical approach to expose the upper cervical spine for internal fixation and bone grafting has been developed to fix AAI. Currently, no anatomic information exists on the anterior transarticular atlantoaxial screw or screw and plate fixation between C1 and C2 in the Indian population. The objective of this study is to assess the anatomic landmarks of C1–C2 vertebrae: entry point, trajectory, screw length, and safety of the procedure.OVERVIEW OF LITERATURE: Methods outlined by Magerl and Harms are the optimal approaches among the dorsal techniques. Contraindications for these techniques include aberrant location of vertebral arteries, fractures of C1–C2 posterior structures. In these cases, anterior transarticular fixation is an alternative. Several available screw insertion trajectories have been reported. Biomechanical studies have demonstrated that adequate rigidity of this fixation is comparable with posterior fusion techniques.METHODS: Direct measurements using Vernier calipers and a goniometer were recorded from 30 embalmed human cadavers. The primary parameters measured were the minimum and maximum lateral and posterior angulations of the screw in the sagittal and coronal planes, respectively, and optimum screw length, if it was placed accurately.RESULTS: The posterior and lateral angles of screw placement in the coronal and sagittal planes ranged from 16° to 30° (mean±standard deviation [SD], 23.93°±3.93°) and 8° to 17° (mean±SD, 13.3°±2.26°), respectively. The optimum screw length was 25–38 mm (mean±SD, 28.76±3.69 mm).CONCLUSIONS: If the screw was inserted without lateral angulation, the spinal canal or cord could be violated. If a longer screw was inserted with greater posterior angulation, the vertebral artery at the posterior or posterolateral aspect of the C1 superior facet could be violated. Thus, 26° and 30° of lateral and posterior angulations, respectively, are the maximum angles permissible to avoid injury of the vertebral artery and violations of the spinal canal or atlanto-occipital joint.

Morphological Analysis on the Occipital Condyles and Review of the Literature / Análisis Morfológico de los Cóndilos Occipitales y Revisión de la Literatura

Most anatomical and biomechanical studies on the craniovertebral junction have involved morphological or morphometric analysis on the occipital condyles. Some of these studies have provided important findings based on different surgical procedures. The shape, size and angle of the occipital condyles and the locations of the intracranial and extracranial orifices of the hypoglossal canal are highly important because they may affect the lateral approaches to the craniovertebral junction. To determine the frequency of occurrence of different morphological types of occipital condyle. 214 occipital condyles in 107 dry human skulls were analyzed and the classification of their morphological types was determined through assessing digitized photographic images. Among the 107 skulls analyzed, 59.8 % were male and 40.2 % were female. Their ages ranged from 11 to 91 years, with a mean of 57.56 years. Of the total of 10 morphological types of occipital condyle that were found, more than 50 % were of the "8", "S" and ring types. Condyles of "8" and "S" shape were the main types found in male skulls: the "8" shape prevailed on the left side and the "S" shape on the right side. However, in female skulls, these two types had equal bilateral distribution.

La mayor parte de los estudios anatómicos y biomecánicos de la unión cráneo-vertebral han sido realizados sobre el análisis morfológico o de la morfometría de los cóndilos occipitales. Algunos de estos trabajos tienen previsto importantes hallazgos basados en diferentes procedimientos quirúrgicos. De tal forma, el tamaño y ángulo del cóndilo occipital bien como su localización de los orificios intracraneales y extracraneales del canal hipogloso son de gran importancia, ya que pueden afectar a los enfoques laterales de la unión cráneo-vertebral. El objetivo del estudio fue determinar la prevalencia de los tipos morfológicos de cóndilos occipitales. Fueron analizados 214 cóndilos de 107 cráneos secos de humanos y la clasificación de los tipos morfológicos fue determinada a partir de los análisis de estudio de imágenes fotográficas digitalizadas. De los 107 cráneos que fueron analizados, 59,8 % eran de sexo masculino y 40,2 % de sexo femenino, cuyas edades comprendidas entre 11 y 91 años con una media de 57.56 años. De un total de 10 tipos morfológicos de los cóndilos occipitales encontrados, más del 50 % eran de tipo ocho, S y anillo. Los cóndilos en forma de "8" y "S" fueron los principales tipos encontrados, en el sexo masculino, la forma en "8" prevaleció en el lado izquierdo, y el tipo morfológico en "S", en el lado derecho del cráneo. Mientras que en el sexo femenino esos dos tipos tuvieron una equitativa distribución bilateral.

Instrumentación cervical en pacientes menores de 10 años / Cervical instrumentation and fusion in children under 10 years old

Introducción: la instrumentación de la columna cervical pediátrica ha ganado terreno en la última década. Las diferencias anatómicas y biomecánicas entre la columna cervical pediátrica y del adulto hacen que la cirugía requiera de una minuciosa preparación toda vez que se utilizan implantes diseñados para adultos. El objetivo de este estudio fue evaluar los resultados posoperatorios en una serie de niños <10 años sometidos a fusión cervical instrumentada, y describir la técnica quirúrgica y las complicaciones. Materiales y Métodos: Se evaluó a 28 pacientes con patología cervical tratados con fusión instrumentada utilizando las técnicas descritas por Roy-Camille y Magerl para masas laterales, de Goel-Harms para C1-C2, y las fusiones occipitocervicales con placas occipitales o rótulas. Los criterios de inclusión fueron: pacientes <10 años, cirugía primaria y un seguimiento mínimo de 2 años. Resultados: La muestra incluyó 17 niñas y 11 niños, con un seguimiento promedio de 3.8 años (rango 2-10). La edad promedio fue de 6.1 años (rango 1.6-10). La tasa promedio de complicaciones generales fue del 32,1%. Los pacientes que tuvieron más complicaciones sufrían: síndromes genéticos [6 casos (21,4%)] y displasias esqueléticas [3 casos (10,7%)]. Trece tenían <6 años, 7 de ellos presentaron complicaciones (53,8%). Conclusiones: La instrumentación cervical en pacientes <10 años demostró ser un procedimiento factible y seguro. Las displasias vertebrales, las anomalías congénitas y los síndromes genéticos, sumados al factor edad <6 años, son las principales variables asociadas a las complicaciones observadas.

Introduction: pediatric cervical spine implants and construction designs had rapidly evolved in the last decade. Anatomic and biomechanical differences between pediatric and adult cervical spine require a thorough preoperative planning, because these implants were originally designed for adults. The objective of this study was to assess the postoperative results of cervical instrumented fusion in children under 10 years old, and to describe the surgical technique and complications. Methods: Twenty-eight children with different cervical pathology treated with instrumented fusion were evaluated. The following procedures were used: Roy-Camille’s and Magerl’s techniques for lateral masses, Goel-Harms’ technique for C1-C2 fusion, and occipital-cervical fusion with occipital plates or screws. Inclusion criteria were: children under 10 years, no prior spine surgery, and minimum follow-up of 2 years. Results: Sample included 17 girls and 11 boys, with a mean follow-up of 3.8 years (range 2-10). Mean age was 6.1 years (range: 1.6-10). Overall complication rate was 32.1%. The highest complication rates were associated with: genetic syndromes [6 cases (21.4%)], skeletal dysplasias [3 cases (10.7%)]. Thirteen patients were <6 years, 7 of them had complications (53.8%). Conclusions: Cervical instrumented fusion in patients <10 years old proved to be a feasible and safe surgical procedure. Vertebral dysplasias, congenital, syndromic anomalies, and being younger than 6 years old are the main factors associated with high complication rates.

New Radiographic Index for Occipito-Cervical Instability

STUDY DESIGN: Retrospective study. PURPOSE: To propose a new radiographic index for occipito-cervical instability. OVERVIEW OF LITERATURE: Symptomatic atlanto-occipital instability requires the fusion of the atlanto-occipital joint. However, measurements of occipito-cervical translation using the Wiesel-Rothman technique, Power's ratio, and basion-axial interval are unreliable because the radiologic landmarks in the occipito-cervical junction lack clarity in radiography. METHODS: One hundred four asymptomatic subjects were evaluated with lateral cervical radiographs in neutral, flexion and extension. They were stratified by age and included 52 young (20-29 years) and 52 middle-aged adults (50-59 years). The four radiographic reference points were posterior edge of hard palate (hard palate), posteroinferior corner of the most posterior upper molar tooth (molar), posteroinferior corner of the C1 anterior ring (posterior C1), and posteroinferior corner of the C2 vertebral body (posterior C2). The distance from posterior C1 and posterior C2 to the above anatomical landmarks was measured to calculate the range of motion (ROM) on dynamic radiographs. To determine the difference between the two age groups, unpaired t-tests were used. The statistical significance level was set at p<0.05. RESULTS: The ROM was 4.8+/-7.3 mm between the hard palate and the posterior C1, 9.9+/-10.2 mm between the hard palate and the posterior C2, 1.7+/-7.2 mm between the molar to the posterior C1, and 10.4+/-12.1 mm between the molar to the posterior C2. There was no statistically significant difference for the ROM between the young- and the middle-aged groups. The intra-observer reliability for new radiographic index was good. The inter-observer reliability for the ROM measured by the hard palate was low, but was better than that by the molar. CONCLUSIONS: ROM measured by the hard palate might be a useful new radiographic index in cases of occipito-cervical instability.

Surgical Treatment for Atlanto-Occipital Subluxation due to Destructive Spondyloarthropathy in a Patient Undergoing Long-Term Hemodialysis

Destructive spondyloarthropathy (DSA) has been reported in patients undergoing long-term hemodialysis. Cervical spinal lesions, including those of the upper cervical spine, are reported to be some of the most common. To our knowledge, we report for the first time, a case of atlanto-occipital subluxation requiring surgical treatment due to severe myelopathy and nuchal pain in a patient undergoing long-term hemodialysis. The patient was a 66-year-old woman who had undergone hemodialysis for 40 years. She visited our hospital due to an acute progression of gait disturbance and severe nuchal pain. Computed tomography showed posterior subluxation of the atlanto-occipital joints. DSA was also observed in the lower cervical spine. Magnetic resonance imaging showed spinal canal stenosis at both the upper and lower cervical levels. We performed Oc-C7 fixation, C1 laminectomy, and C3-C7 laminoplasty. We first recognized that the atlanto-occipital subluxation was caused by the extremely long-term, in this case, 40 years, hemodialysis.

Pitfalls in the Management of Atlanto-Occipital Dislocation

Atlanto-occipital dislocation (AOD) is rarely seen in clinic because it is characteristically immediately fatal. With recent progress in the pre-hospital care, an increasing number of AOD survivors have been reported. However, because the pathophysiology of AOD is not clearly understood yet, the appropriate strategy for the initial management remains still unclear. We report a case of successful AOD treatment and describe important points in the management of this condition. It is important to note that abducens nerve palsy is a warning sign of AOD and that AOD can result in a life-threatening distortion of the arteries and the brain stem. We recommend the application of a halo vest to protect the patient's neural and vascular competence as the immediate initial step in the treatment of AOD. Horn's grading system is useful in assessing indications for surgery. Finally, when performing posterior fixation, C2 should be included because of the anatomy of the ligamentous architecture.

Pathomorphological change of the atlanto-occipital segment of vertebral artery related with cervical vertigo / 中国骨伤

<p><b>OBJECTIVE</b>To explore the pathomorphological change of the atlanto-occipital segment of vertebral artery (V3 part) related with cervical vertigo.</p><p><b>METHODS</b>From June 1999 to November 2011, the pathomorphological change of the atlanto-occipital segment of vertebral artery were observed in 1680 patients with cervical vertigo using 3D-CTA technology. The clinical data of these patients were analyzed. There were 783 males and 897 females, aged from 22 to 70 years old with an average of 52.8 years old. Doppler examination showed vertebral basilar artery flow velocity to speed up or slow down.</p><p><b>RESULTS</b>The blood vessel of 3360 branches were detected in 1680 patients and 2778 branches were detected out vascular anomaly. And 829 branches were in V1 segment, 421 were in V2, 328 were in V3, 1190 were in V4. The pathomorphological changes in the atlanto-occipital segment (V3) of vertebral artery included angiospasm, congenital absence, abnormal exit, localized stenosis.</p><p><b>CONCLUSION</b>There are 4 kinds of pathomorphological changes in the atlanto-occipital segment of vertebral artery related with cervical vertigo. The 3D-CTA result can be used to judge prognosis and adopt reasonable treatment for the patients.</p>

Posterior atlanto-occipital and atlanto-axial area and its surgical interest / Interesse cirúrgico da junção atlanto-occipital e atlanto-axial

Classic anatomical studies describe two membranes – atlanto-occipital and atlanto-axial in the posterior aspect of the craniocervical region. During many surgical procedures in this area, however, we have not found such membranes. Objective To clarify the anatomical aspects and structures taking part of the posterior atlanto-occipital and atlanto-axial area. Method Analysis of histological cuts of three human fetuses and anatomical studies of 8 adult human cadavers. Results In both atlanto-occipital and atlanto-axial areas, we have observed attachment between suboccipital deep muscles and the spinal cervical dura. However, anatomical description of such attachments could not be found in textbooks of anatomy. Conclusion Our study shows the absence of the classical atlanto-occipital and atlanto-axial membranes; the occipito-C1 and C1-C2 posterior intervals are an open area, allowing aponeurotic attachment among cervical dura mater and posterior cervical muscles. .

Em livros clássicos de anatomia é referida a existência de duas membranas, atlanto-occipital e atlanto-axial, participando do fechamento da região cranio-cervical. Entretanto, em frequentes procedimentos cirúrgicos que envolvem esta região, jamais detectamos a presença de tais membranas. Objetivo Estudar os aspectos anatômicos e as estruturas que participam do fechamento posterior dos espaços atlanto-occipital e atlanto-axial. Método Estudo de cortes histológicos de três fetos humanos e estudos anatômicos em 8 cadáveres humanos adultos. Resultados Em ambos os espaços, atlanto-occipital e atlanto-axial, encontramos uma aderência entre as estruturas musculares profundas e a dura-mater, sem as membranas atlanto-occipital e atlanto-axial descritas nos livros clássicos de anatomia. Conclusão Não foram encontradas as membranas atlanto-occipital e atlanto-axial no material estudado; os espaços atlanto-occipital e atlanto-axial são abertos permitindo expansões aponeuróticas entre os músculos profundos e a dura-mater. .

Fratura de côndilos occipitais / Occipital condyles fractures

A fratura de côndilos occipitais é uma afecção considerada rara, mas que pode estar sendo subdiagnosticada. Fatores como a apresentação clínica variável, o exame físico frustro e a não identificação por radiografia simples dificultam esse diagnóstico, podendo levar a complicações como paralisia de nervos cranianos caudais e até mesmo a óbito. O presente estudo tem como objetivo revisar a literatura pertinente às fraturas de côndilos occipitais, com enfoque nas considerações anatômicas da junção craniocervical e ressaltando aspectos fisiopatológicos, parâmetros clínicos e as controvérsiasquanto ao tratamento. O incremento das técnicas radiológicas e a maior disponibilidade e uso de tomografia computadorizada possibilitaram o aumento do número de casos descritos dessas fraturas nas últimas décadas. A apresentação clínica é inespecífica e a tomografia da junção craniocervical é o método diagnóstico de escolha. A ausência de diagnóstico é responsável por sequelas, como déficits neurológicos, e foram descritas taxas de mortalidade de até 16% em casos de fraturas bilaterais. Omecanismo de injúria exato não é bem conhecido, mas a maioria dos autores indica a hiperextensão do pescoço associada à força vertical sobre a junção craniocervical. O tratamento é controverso, por causa da inconsistência nos resultados obtidos com o tratamento conservador baseado na classificação de Anderson e Montesano, em comparação com o escasso número de doentes tratados cirurgicamente.

The occipital condyle fractures are rare lesions, but they may have been under-diagnosed. Factors such as variable clinical presentation, inconclusive physical examination and no identification in the simple radiography difficult the diagnosis and may lead to complications such as paralysis of cranial nerves and death. This study aims to review the literature about occipital condyle fractures, emphasizing the anatomical considerations of the craniovertebral junction, pathophysiological view, clinical presentationand controversies regarding treatment. The improvement in radiological techniques and the increased availability and usage of computed tomography allowed the growth of reported cases of these fracturesin recent decades. The clinical presentation is nonspecific and CT of the craniocervical junction is the diagnostic method of choice. The absence of a diagnosis is responsible for sequel, such as neurologic deficits, and as mortality rates are of up to 16% in cases of bilateral fractures. The exact mechanism of injury is not well known, but most authors indicate the hyperextension of the neck associated with the vertical force on the craniocervical junction. The treatment is controversial due to the inconsistencies in the results obtained with conservative treatment based on the classification of Anderson and Montesano, compared to the small number of patients treated surgically.

Traumatic Atlanto-Occipital Dislocation Presenting With Dysphagia as the Chief Complaint: A Case Report

We report a patient with traumatic atlanto-occipital dislocation who presented with dysphagia as the chief complaint. A 59-year-old man complained of swallowing difficulty for 2 months after trauma to the neck. On physical examination, there was atrophy of the right sternocleidomastoid and upper trapezius muscles, and the tongue was deviated to the right. In a videofluoroscopic swallowing study, penetration and aspiration were not seen, food residue remained in the right vallecula and pyriform sinus, and there was decreased motion of the soft palate, pharynx and larynx. Electromyography confirmed a right spinal accessory nerve lesion. Magnetic resonance imaging confirmed atlanto-occipital dislocation. Dysphagia in atlanto-occipital dislocation is induced by medullary compression and lower cranial nerve injury. Therefore, in survivors who are diagnosed with atlanto-occipital dislocation, any neurological symptoms should be carefully evaluated.

Cervical Myelopathy Secondary to Atlanto-occipital Assimilation: The Usefulness of the Simple Decompressive Surgery

Atlanto-occipital assimilation is one of the most common osseous anomalies observed at the craniocervical junction. Most patients with atlas assimilation show no symptom, but some have neurological problems such as myelopathy that may require surgical treatment. Occipitocervical fusion may be required if atlato-occipital assimilation is accompanied by occipito-axial instability. However, in cases of symptomatic atlas assimilation with minor cord compression without instability, simple decompressive surgery may be the treatment modality. This report describes a case of successful treatment of a patient with myelopathy secondary to atlanto-occipital assimilation without instability, using posterior simple decompressive surgery.

Combined Chronic Occipito-atlantal and Atlanto-axial Rotator Fixation with Cerebral Palsy

Occipito-atlantalrotatory subluxation that occurs in conjunction with atlanto-axial rotator fixation is extremely rare. The common clinical characteristics are painful torticollis and cock robin position presented with the head tilted to one side and rotated to the other side. The object of this report is to emphasize that AARF combined with OARF may be caused by a variety of conditions, to be must need algorithm for proper management, apparently. A torticollis patient who had cerebral palsy presented with severe nuchal pain and wryneck for a long period. The patient had a history of fallen down 16 years ago which caused severe nuchal pain. The conservative management had failed to correct the deformity and instability. we decided to operate using occiput-C1-C2 arthrodesis and C3-4-5 bilateral screw fixation for reinforcement. Now he doesn't have neurologic deficit and shows good outcome enough to sustain his head, not using his hands, in his daily life.

Surgical Outcomes and Complications after Occipito-Cervical Fusion Using the Screw-Rod System in Craniocervical Instability

OBJECTIVE: Although there is no consensus on the ideal treatment of the craniocervical instability, biomechanical stabilization and bone fusion can be induced through occipito-cervical fusion (OCF). The authors conducted this study to evaluate efficacy of OCF, as well as to explore methods in reducing complications. METHODS: A total of 16 cases with craniocervical instability underwent OCF since the year 2002. The mean age of the patients was 51.5 years with a mean follow-up period of 34.9 months. The subjects were compared using lateral X-ray taken before the operation, after the operation, and during last follow-up. The Nurick score was used to assess neurological function pre and postoperatively. RESULTS: All patients showed improvements in myelopathic symptoms after the operation. The mean preoperative Nurick score was 3.1. At the end of follow-up after surgery, the mean Nurick score was 2.0. After surgery, most patients' posterior occipito-cervical angle entered the normal range as the pre operation angle decresed from 121 to 114 degree. There were three cases with complications, such as, vertebral artery injury, occipital screw failure and wound infection. In two cases with cerebral palsy, occipital screw failures occurred. But, reoperation was performed in one case. CONCLUSION: OCF is an effective method in treating craniocervical instability. However, the complication rate can be quite high when performing OCF in patients with cerebral palsy, rheumatoid arthritis. Much precaution should be taken when performing this procedure on high risk patients.

Feasibility of Ultrasound Guided Atlanto-occipital Joint Injection

OBJECTIVE: To evaluate the feasibility of ultrasound guided atlanto-occipital joint injection. METHOD: Six atlanto-occipital joints of three cadavers were examined. Cadavers were placed in prone position with their head slightly rotated towards the contra-lateral side. The atlanto-occipital joint was initially identified with a longitudinal ultrasound scan at the midline between occipital protuberance and mastoid process. Contrast media 0.5cc was injected into the atlanto-occipital joint using an in-plane needle approach under ultrasound guide. The location of the needle tip and spreading pattern of the contrast was confirmed by fluoroscopic evaluation. RESULTS: After ultrasound guided atlanto-occipital joint injection, spreading of the contrast media into the joint was seen in all the injected joints in the anterior-posterior fluoroscopic view. CONCLUSION: The ultrasound guided atlanto-occipital injection is feasible. The ultrasound guided injection by Doppler examination can provide a safer approach to the atlanto-occipital joint.