Posterior Atlantoaxial Screw Placement in a Portuguese Population: A Morphometric Analysis Based on Computed Tomography Scan Measurements / Colocação de parafusos atlantoaxiais posteriores em uma população portuguesa: Uma análise morfométrica baseada em medidas de tomografia computadorizada

Abstract Objective The present study aims to evaluate the screw length and trajectory angles for posterior atlantoaxial fixation in a Portuguese population, through the study of cervical computed tomography (CT) scans. Methods Cervical CT scans of 50 adults were measured according to predefined screw trajectories of C1-C2 transarticular (C1C2TA), C1 lateral mass (C1LM), C2 pedicle (C2P), C2 pars and C2 laminar (C2L) screws. For each of these trajectories, screw length and angles were measured and compared between males and females. Results For the C1C2TA screw trajectory, the mean length, medial, and cranial angles were 34.12 ± 3.19 mm, 6.24° ± 3.06, and 59.25° ± 5.68, respectively, and for the C1LM screw trajectory, they were 27.12 ± 2.15 mm, 15.82° ± 5.07, and 13.53° ± 4.80, respectively. The mean length, medial, and cranial angles for the C2P screw trajectory were 23.44 ± 2.49 mm, 27.40° ± 4.88, and 30.41° ± 7.27, respectively; and for the C2 pars screw trajectory, they were 16.84 ± 2.08 mm, 20.09° ± 6.83, and 47.53° ± 6,97. The mean length, lateral, and cranial angles for the C2L screw trajectory were 29.10 ± 2.48 mm, 49.80° ± 4.71, and 21.56° ± 7.76, respectively. There were no gender differences except for the lengths of the C1C2TA (p= 0,020) and C2L (p= 0,001) screws, which were greater in males than in females. Conclusion The present study provides anatomical references for the posterior atlantoaxial fixation in a Portuguese population. These detailed data are essential to aid spine surgeons to achieve safe and effective screw placement.

Resumo Objetivo O presente estudo tem como objetivo avaliar o comprimento e os ângulos de trajetória do parafuso para fixação atlantoaxial posterior em uma população portuguesa por meio do estudo de tomografia computadorizada (TC) cervical. Métodos Tomografias computadorizadas cervicais de 50 adultos foram analisadas quanto às trajetórias pré-definidas dos parafusos transarticulares C1-C2 (C1C2TA), na massa lateral de C1 (C1LM), no pedículo de C2 (C2P) e na pars de C2 e C2 laminar (C2L). O comprimento e os ângulos dos parafusos em cada uma destas trajetórias foram medidos e comparados entre homens e mulheres. Resultados O comprimento médio e ângulos medial e cranial da trajetória do parafuso C1C2TA foram de 34,12 ± 3,19 mm, 6,24° ± 3,06 e 59,25° ± 5,68, respectivamente; as medidas da trajetória do parafuso C1LM foram 27,12 ± 2,15 mm, 15,82° ± 5,07 e 13,53° ± 4,80. O comprimento médio e os ângulos medial e cranial da trajetória do parafuso C2P foram de 23,44 ± 2,49 mm, 27,40° ± 4,88 e 30,41° ± 7,27, respectivamente; as medidas da trajetória do parafuso da pars de C2 foram 16,84 ± 2,08 mm, 20,09° ± 6,83 e 47,53° ± 6,97. O comprimento médio e ângulos lateral e cranial da trajetória do parafuso C2L foram de 29,10 ± 2,48 mm, 49,80° ± 4,71 e 21,56° ± 7,76, respectivamente. Não houve diferenças entre os gêneros, à exceção do comprimento dos parafusos C1C2TA (p= 0,020) e C2L (p= 0,001), que foi maior no sexo masculino do que no feminino. Conclusão O presente estudo fornece referências anatômicas para a fixação atlantoaxial posterior em uma população portuguesa. Estes dados detalhados são essenciais para ajudar os cirurgiões de coluna a colocar os parafusos de maneira segura e eficaz.

Research progress of causes and strategies in revision surgery for atlantoaxial dislocation / 中国骨伤

Atlantoaxial dislocation (AAD) is a kind of life-threatening atlantoaxial structural instability and a series of neurological dysfunction caused by common multidisciplinary diseases. The operation risk is extremely high because it is adjacent to the medulla oblongata and the location is deep. With the increase of the number of operations in the upper cervical region, postoperative complications such as failure of internal fixation, non fusion of bone graft and poor prognosis gradually increase.Incomplete primary operation, non fusion of bone graft, infection and congenital malformation are the potential causes. In addition, considering the objective factors such as previous graft, scar formation and anatomical marks changes, revision surgery is further difficult. However, there is currently no standard or single effective revision surgery method. Simple anterior surgery is an ideal choice in theory, but it has high risk and high empirical requirements for the operator;simple posterior surgery has some defects, such as insufficient reduction and decompression;anterior decompression combined with posterior fixation fusion is a more reasonable surgical procedure, but many problems such as posterior structural integrity and multilevel fusion need to be considered.This article reviews the causes and strategies of AAD revision surgery.

Subluxación rotatoria atloaxoidea o síndrome de Grisel. A propósito de un caso / Rotatory subluxation of the atlantoaxial joint or Grisel's syndrome. Case report

La tortícolis es una contractura involuntaria unilateral del esternocleidomastoideo y de la musculatura posterior del cuello que causa la inclinación de la cabeza hacia un lado. Se han descrito múltiples causas de torticolis siendo una de ellas la subluxación atloaxoidea atraumática asociada a un proceso de carácter inflamatorio en la región de cabeza y cuello, llamada síndrome de Grisel. Aunque la mayoría de los pacientes suelen recuperarse sin secuelas tras tratamiento médico existe la posibilidad de complicaciones graves con déficits funcionales, de ahí la importancia de la realización de un diagnóstico y tratamiento precoz.

Torticollis is an unilateral involuntary contracture of the sternocleidomastoid and posterior neck musculature that causes the head tilts to the one side. Multiple causes of torticolis have been described, one of them being the non-traumatic rotatory subluxation of the atlantoaxial joint associated with an inflammatory process in the head and neck region, called Grisel's syndrome. Although most patients usually recover without sequels after medical treatment, there is the possibility of serious complications with functional deficits, that is why the importance of an early diagnosis and treatment of this potology.

Correlative analysis of cervical curvature and atlantoaxial instability / 中国骨伤

OBJECTIVE@#To investigate the correlation between the changes of cervical curvature and atlantoaxial instability.@*METHODS@#The correlation between the changes of cervical curvature and atlantoaxial instability was retrospectively studied in 50 outpatients with abnormal cervical curvature (abnormal cervical curvature group) from January 2018 to December 2019. There were 24 males and 26 females in abnormal cervical curvature group, aged from 18 to 42 years old with an average of(30.62±5.83) years. And 53 patients with normal cervical curvature (normal cervical curvature group) during the same period were matched, including 23 males and 30 females, aged from 21 to 44 years with an average of(31.98±6.11) years. Cervical spine X-ray films of 103 patients were taken in lateral position and open mouth position. Cervical curvature and variance of bilateral lateral atlanto-dental space(VBLADS) were measured and recorded, Pearson correlation coefficient analysis was used to study the correlation between the changes of cervical curvature and atlantoaxial instability.@*RESULTS@#Atlantoaxial joint instability accounted for 39.6%(21/53) in normal cervical curvature group and 84.0%(42/50) in abnormal cervical curvature group. There was significant difference between two groups(P<0.01). VBLADS in abnormal cervical curvature group was (1.79±1.01) mm, which was significantly higher than that in normal cervical curvature group(0.55±0.75) mm(P<0.01). Pearson correlation coefficient analysis showed that the size of cervical curvature was negatively correlated with VBLADS.@*CONCLUSION@#Cervical curvature straightening and inverse arch are the cause of atlantoaxial instability, the smaller the cervical curvature, the more serious the atlantoaxial instability.

Traumatic Atlantoaxial Rotatory Subluxation in Adult: Case Report

Traumatic atlantoaxial rotatory subluxation (AARS) is generally found in pediatric patients, rarely found in adults, being a life-threatening condition especially when early diagnosis is not possible, which can lead to severe late neurological deficits.We describe a 38-year-old patient, victim of physical aggression caused by strangulation attempt who developed AARS, an uncommontraumatic cause. During the hospital care, the early diagnosis allowed us to institute a conservative treatment, which made the case uncommon, since most of the time surgical treatment is imperative. With the patient awake and under analgesia, a closed reduction was performed that promoted immediate pain relief, followed by a prescription of wearing a Philadelphia-type collar for 8 weeks. During the follow-up, cervical spine radiographies demonstrated no subluxation after removing the cervical collar. The patient was asymptomatic after 6months of treatment. This case supports the importance of nonoperative management of AARS in selected cases.

Treatment strategy and curative effect analysis of os odontoideum complicated with atlantoaxial joint dislocation / 中国骨伤

OBJECTIVE@#To explore the treatment strategy and clinical efficacy for os odontoideum complicated with atlantoaxial dislocation.@*METHODS@#The clinical data of 17 patients with os odontoideum complicated with atlantoaxial dislocation surgically treated from January 2006 to January 2015 were retrospectively analyzed, including 7 males and 10 females, aged 17 to 53 (43.1±11.3) years old;course of disease was 3 to 27(10.2±6.9) months. All patients received cranial traction before operation, 12 of 14 patients with reducible dislocation were treated by posterior atlantoaxial fixation and fusion, and 2 patients with atlantooccipital deformity were treated by posterior occipitocervical fixation and fusion;3 patients with irreducible alantoaxial dislocation were treated by transoral approach decompression combined with posterior atlantoaxial fixation and fusion. The operation time, intraoperative blood loss and perioperative complications were recorded. Visual analogue scale (VAS) and Japanese Orthopaedic Association (JOA) score were used to evaluate the change of neck pain and neurological function. Atlantoaxial joint fusion rate was evaluated by CT scan.@*RESULTS@#The operation time of posterior fixation and fusion ranged from 86 to 170 (92.2±27.5) min, and the intraoperative blood loss was 200-350 (250.7±65.2) ml. No vertebral artery injury and spinal cord injury were recorded. Among the patients underwent atlantoaxial fixation and fusion, 1 patient with reducible dislocation fixed by C@*CONCLUSION@#Surgical treatment of os odontoideum complicated with atlantoaxial dislocation can achieve satisfactory results, improve the patient's neurological function and improve the quality of life, however the surgical options needs to be individualized.

Grisel Syndrome: Case Report

We report a case of a rare disease, Grisel syndrome, which manifests as a kind of rotational fixation of the atlas on the axis, resulting from an infectious process of the upper airways. In the present report, we discuss etiology, clinical presentation, diagnosis, treatment and outcome after intervention.

Traction for the treatment of traumatic atlantoaxial subluxation in adults / 中国骨伤

OBJECTIVE@#To observe the application of modified traction therapy in traumatic atlantoaxial subluxation in adults.@*METHODS@#The clinical data of 31 patients with atlantoaxial subluxation treated from March 2018 to June 2019 were restropectively analyzed. There were 15 males and 16 females, aged from 18 to 68 years old with an average of 39 years old, including 10 cases of 18-40 years, 15 cases of 41-60 years, 6 cases of 51-68 years. The main manifestations of the patients were limited neck movement, pain, and atlantoaxial CT scan showed different degrees of atlantoaxial subluxation. Three dimensional multifunctional traction bed was used for traction for 2 min, relaxation for 10 s. The traction angle starts from the rearward extension of 5°-10° and weight from 3-6 kg. The weight increased by 1 kg every two days until the symptoms were improved. Traction time was 30 min twice a day and 10 days for a course of treatment. One course of treatment was performed in patients with 1-2 mm left and right equal width of atlantoaxial space, and two courses of treatment were performed in patients with 3-4 mm left and right equal width of atlantoaxial space, and the course of treatment could be increased to 3 months in especially patients with serious problems, such as 4 mm left and right equal width of atlantoaxial space and no improvement after conventional treatment. The criteria to evaluate the clinical effect was cure:no pain in the neck, normal range of neck movement, CT showed normal atlantoaxial space and odontoid process was in the middle, patients with normal neck movement were followed up 1 month after the end of treatment;improvement:neck pain was significantly improved and CT showed that the left and right atlantoaxial space was less than 1 mm in equal width.@*RESULTS@#Among the 31 patients, 17 cases were cured by one course of treatment, 11 cases were cured by 2 courses of treatment, and 2 caseswere improved.@*CONCLUSION@#The modified traction therapy has obvious effect on adult traumatic atlantoaxial subluxation, especially the subluxation of 3-4 mm equal width in left and right atlantoaxial space, and this method is safe and reliable with good efficacy and the patients without discomfort.

Retro-odontoid pseudotumor: a poorly recognized alteration of the craniocervical junction

SUMMARY INTRODUCTION Retro-odontoid pseudotumor (ROP) is a rare disease that affects the atlantoaxial joint and, in general, is associated with local biomechanical alterations that may or may not cause instability. METHODS Descriptive study of the literature available in databases MEDLINE/PubMed, LILACS, and Scopus. The research was conducted in April 2019. DISCUSSION ROP is, possibly, a syndromic designation that encompasses a significant variety of diseases of the atlantoaxial joint. There are different pathophysiological mechanisms implicated in its genesis. The patients, almost in their entirety, present with severe myelopathy, and most of them are treated surgically, with the posterior decompression being the most commonly used method, with or without arthrodesis. Evolution is usually favorable. CONCLUSION The ROP is still poorly recognized as a differential diagnosis between the diseases of the cranial-cervical junction. The information available in the literature analyzed was based mainly on the study of reports or case series; therefore, it is insufficient to define conducts with a high level of scientific evidence.

RESUMO INTRODUÇÃO O pseudotumor retro-odontoide (PRO) é uma patologia rara que acomete a articulação atlantoaxial e, em geral, está associada a alterações biomecânicas locais que podem ou não causar instabilidade. METODOLOGIA Estudo descritivo da literatura disponível nas bases de dados Medline/PubMed, Lilacs e Scopus. A pesquisa foi realizada em abril de 2019. DISCUSSÃO O PRO é, possivelmente, uma designação sindrômica que abrange uma variedade significativa de doenças da articulação atlantoaxial. Existem diferentes mecanismos fisiopatológicos implicados em sua gênese. Os pacientes, quase em sua totalidade, apresentam quadro de mielopatia grave e a maioria deles é tratada cirurgicamente, sendo a descompressão posterior o método mais utilizado, com ou sem artrodese. A evolução costuma ser favorável. CONCLUSÃO O PRO ainda é pouco reconhecido como diagnóstico diferencial entre as doenças da junção crânio-cervical. As informações disponíveis na literatura analisada foram baseadas principalmente no estudo de relatos ou séries de casos, sendo, portanto, insuficientes para definir condutas com alto nível de evidência científica.

One stage temporary atlantoaxial segmental fixation and reduction for Grauer type IIB dens fractures in teenagers / 中国骨伤

OBJECTIVE@#To assess the clinical results of one stage temporary atlantoaxial segmental fixation and reduction for Grauer type IIB dens fractures in teenagers.@*METHODS@#From February 2009 to April 2015, 19 teenagers with Grauer type IIB dens fractures not amenable to anteiror screw fixation were enrolled and treated using one stage temporary atlantoaxial segmental fixation and reduction without fusion. There were 14 males and 5 females, aged from 14 to 32 years with an average of (24.6±5.0 ) years. The internal fixation was removed after bone healing confirmed by CT scan. At the last follow-up (at least 1 year after internal fixation removal), dynamic CT was used to assess the atlantoaxial rotation activity. Visual analogue scale (VAS) was recorded before the first operation, before the second operation (removal of internal fixation) and at the last follow-up. Neck Disability Index(NDI) was used to evaluate the efficacy before the second operation (removal of internal fixation) and the last follow-up.@*RESULTS@#After operation, 2 patients developed the symptoms of occipital nerve stimulation such as numbness and pain in the occipitocervical region, and were treated with drugs such as dehydration and neurotrophic drugs, and the symptoms were relieved after 1 to 2 months. All the internal fixations were removed and all the patients were followed up more than 1 year, with time ranging from 18 to 25 months and an average of (21.47±2.41) months. The time of bone fusion after operation was 6 to 10 months with the mean of(8.21±1.27) months. Secondary surgical removal of internal fixation were performed immediately after fracture healing without internal fixation failure. The symptoms of neck pain improved significantly after operation, VAS score decreased from 6.74±0.65 before operation to 0.42±0.51 at the last follow-up after the second operation (removal of internal fixation), with statistically significant differences(<0.01). The NDI value decreased from (10.58±2.04)% before the second operation (removal of internal fixation) to (3.79±2.23)% at the last follow-up after the second operation (removal of internal fixation), with statistically significant difference(<0.01). At the last follow-up after the second operation (removal of internal fixation), dynamic CT showed that the unilateral rotation of the atlantoaxial spine reached (15.73±5.57)° to the left, (15.55±5.78)° to the right, and the overall rotation of the atlantoaxial spine was (31.28±10.71)°.@*CONCLUSIONS@#One stage temporary atlantoaxial segmental fixation and reduction for the treatment of Grauer type IIB dens fractures not amenable to anteiror screw fixation in teenagers can avoid the loss of atlantoaxial rotation function caused by atlantoaxial fusion, and to some extent retain the rotation activity of atlanto-axial joint.

In vivo measurement of three-dimensional motion of the upper cervical spine using CT three-dimensional reconstruction / 中国骨伤

OBJECTIVE@#Using the CT three-dimensional reconstruction to measure the activity degree of atlanto-occipital joint and the atlantoaxial joint in different directions and its coupling movement in healthy volunteers, and three dimensional motion range of the maximum rotation position of the upper cervical spine of cervical spondylosis patients, and to analyze the differences, verifing the reliability of the method at the meantime.@*METHODS@#From January 2014 to June 2015, 20 healthy adult subjects(healthy adult group), and 26 patients with cervieal spondylosis(cervical spondylosis group) were selected. In healthy adult group, there were 11 males and 9 females, aged from 22 to 26 years old with an average of (24.0±1.2) years, and in cervical spondylosis group, there were 24 males and 2 females, aged from 36 to 72 years old with an average of (52.8±8.6) years. Healthy adults underwent CT examination in neutral position, maximum right rotation, maximum right lateral bending, maximum flexion and extention, and cervical spondylosis patients underwent CT examination in neutral position, maximum right rotation. Then the software Mimics was used to reconstruct occiput (Oc), atlas(C1) and axial(C2) vertebral three-dimensional image. Three virtual non-collinear markers were positioned on prominent structures of foramen magnum, C1 and C2. The 3D spatial coordinates of these virtual anatomical markers entail the definition of an anatomical local coordinate system which represent the position and orientation of the bones. Segmental motions were calculated using Eulerian angle in three major planes, and the difference between cervical spondylosis group and healthy adult group were compared. Due to the inaccuracy in anatomical landmark idenrification, two groups were measured 3 times, and the reliability of the experimental metnod was verified by the intra-group correlation (intra-group ICC) and the inter-group correlation coefficient(inter-group ICC).@*RESULTS@#Reliability verification results:the intra-group ICC and inter-group ICC results were all above 0.90, and the measurement method had high reliability. Three-dimensional activity of the upper cervical spine in healthy adults:the atlanto-occipital joint had(-6.8±1.5)° coupled left lateral bending and (8.9±2.0)° coupled extension in the maximum right rotation position, and the motion of atlanto-occipital joint had low activity[maximum was(5.3±2.6)°] in the remaining 3 positions; the rotation of atlanto-axial joint was(37.9±5.1)°, accounting for 52.34% of the total cervical spine activity[(72.4±5.0)°] in the maximum right rotation position, and rotational motion was still prominent in the remaining three positions. The relative translations of the upper cervical spine in all direction were small. The average axial rotation angle [(62.0±3.4)] ° of the total cervical spine in cervical spondylosis group was significantly lower than that in the healthy adult group, but the mean axial rotation angles of the atlanto-occipital and the atlantoaxial joint were not significantly different from those of the healthy adults(>0.05).@*CONCLUSIONS@#The three-dimensional CT reconstruction method has high reliability, which can be applied to measure the movement of spine. The upper cervical spine contributed the most to the direction of rotation, and the movement in all directions are accompanied by coupled motion in the other direction. There was no significant difference in the rotation of the upper cervical spine between cervical spondylosis patients and normal subjects.

Bilateral atlantoaxial lamina hook and atlantoaxial joint space screw for the treatment of acute type I transverse ligament injury in school-age children / 中国骨伤

OBJECTIVE@#To evaluate the effect of bilateral atlantoaxial lamina hook and atlantoaxial joint space screw combined with autologous iliac bone graft on atlantoaxial dislocation caused by acute type I transverse ligament injury in school-age children.@*METHODS@#From February 2006 to February 2019, 8 school-age children with atlantoaxial dislocation caused by acute type I transverse ligament injury were systematically reviewed, including 6 males and 2 females; aged 9 to 12 years old; 8 acute injuries included 4 high-level falls, 2 car accidents and 2 sports injuries; the atlantoaxial interval(ADI) was 5 to 8 mm. Eight cases presented with pain, stiffness, numbness and cervical spine dysfunction in different degrees. Two of them were accompanied by nerve compression and ASIA grade D. The preoperative C₁,₂ angle averaged 20.7° to 23.4°. All patients received cranial traction and surgical treatment after complete reduction or atlantoaxial reduction. The changes of Japanese Orthopaedic Association(JOA) score, space available for the cord(SAC), neck disability index(NDI), ADI, ASIA classification(ASIA) injury classification(1992) and C₁,₂ angle before and after treatment were observed.@*RESULTS@#The average follow-up time was 8 to 156 months. Clinical and radiological follow-up showed that the atlantoaxial joint was completely relieved, the reduction was satisfactory and the arthrodesis was stable. Nerve and vascular injuries associated with this technique were not observed. JOA score, SAC, NDI, C₁,₂ angle of the last follow-up of the children were significantly improved. Two children of ASIA grade D recovered to grade E.@*CONCLUSIONS@#Bilateral atlantoaxial lamina hook and atlantoaxial joint space screw combined with autologous iliac bone graft is simple, less bleeding, strong stability and high fusion rate. It is an ideal surgical procedure for acute type I transverse ligament injury with atlantoaxial dislocation in school-age children.

A temporary disc-like structure at the median atlanto-axial joint in human fetuses / 대한해부학회지

Torticollis and Atlantoaxial Rotatory Subluxation after Chiropractic Therapy

Torticollis is an abnormal, asymmetric head or neck position which usually caused by imbalance of paracervical muscles. The traumatic torticollis can be caused by following events; atlantoaxial rotatory subluxation, atlantoaxial dislocation, cervical vertebral fractures, and injury to the cervical musculature. Especially, acute traumatic atlantoaxial rotatory subluxation usually presents limitation of cervical range of motion without pain or neurologic deficit. We report a case of a 58 year-old man who developed the acute atlantoaxial rotatory subluxation right after the chiropractic therapy, which induced the limitation of cervical range of motion to 52.5% of normal range. The magnetic resonance image revealed the facture of the odontoid process and the partial injury in transverse ligaments of the atlas. He underwent intramuscular botulinum toxin injection and 10 days of continuous cervical traction 15 hours a day using a 5 kg weight. The range of the cervical motion restored up to 90.2% of normal range.

Análisis morfométrico del axis para la fijación atlantoaxial / Morphometric analysis of the axis for atlantoaxial fixation

El objetivo de este estudio fue evaluar de manera integral los parámetros morfométricos de la vértebra axis (C2) en la población mexicana involucrados en la realización de procedimientos quirúrgicos con el fin de proveer datos cuantitativos indispensables en su abordaje quirúrgico. Para este estudio se utilizaron un total de 576 vértebras axis (C2) de población mexicana contemporánea. Las mediciones de las vértebras se efectuaron bilateralmente utilizando un vernier digital milimétrico con una precisión de 0.01 mm (Mitutoyo Digimatic w/Absolute Encoders- Series 500). Un total de 576 vértebras axis (C2), fueron medidas de manera bilateral, todas nuestras mediciones se reportaron en mm. El promedio del ancho del pedículo fue de 8,96 mm con una DE ± 2,11 mm. El promedio de la altura del pedículo fue de 10,82 mm con una DE de ± 1,89 mm. El promedio de la altura del proceso odontoideo fue de 16,90 mm con una DE de ± 2,99 mm. El promedio del ancho del proceso odontoideo fue de 9,99 mm con una de DE de ± 0,80 mm. El promedio del diámetro de la faceta articular fue de 8,44 mm con una DE de ± 1,04 mm. El promedio del diámetro AP del cuerpo vertebral fue de 15,11 mm con una DE de ± 1,88 mm. El promedio del diámetro trasverso del cuerpo vertebral fue de 17,93 mm con una DE de ± 2,22 mm. El promedio de la altura del cuerpo vertebral fue de 18,54 mm con una DE de 2,38 mm. El promedio de la altura de las láminas fue de 11,53 mm con una DE de ± 1,39 mm. El promedio del ancho de las láminas fue de 6,10 mm con una DE de ± 1,44 mm. Los resultados obtenidos en nuestras mediciones demuestran una variación con los resultados de otros autores en diferentes estudios de piezas osteológicas y de estudios de imagen del axis (C2), lo que sugiere, con el fin de reducir los riesgo de daño a estructuras neurovasculares, utilizar técnicas y medidas especiales para la estabilización atlantoaxial de la población mexicana.

The aim of the study was to evaluate the morphometric parameters of the axis vértebra (C2) in the Mexican population involved in the performance of surgical procedures in order to provide essential quantitative data in their surgical approach. A total of 576 axis vertebrae (C2) of contemporary Mexican population were used for this study. The measurements of the vertebrae were made bilaterally using a millimeter digital vernier with an accuracy of 0.01 millimeters (Mitutoyo Digimatic w / Absolute Encoders - Series 500). A total of 576 axis vertebrae (C2) were measured bilaterally, all our measurements were reported in millimeters. The average width of the pedicle was 8.96 mm with a SD ± 2.11 mm. The average height of the pedicle was 10.82 mm with a SD of ± 1.89 mm. The average height of the odontoid process was 16.90 mm with a SD of ± 2.99 mm. The average width of the odontoid process was 9.99 mm with a SD of ± 0.80 mm. The average diameter of the articular facet was 8.44 mm with a SD of ± 1.04 mm. The average diameter of the AP of the vertebral body was 15.11 mm with a SD of ± 1.88 mm. The average transverse diameter of the vertebral body was 17.93 mm with a SD of ± 2.22 mm. The average height of the vertebral body was 18.54 mm with a SD of 2.38 mm. The average height of the lamina was 11.53 mm with a SD of ± 1.39 mm. The average width of the lamina was 6.10 mm with a SD of ± 1.44 mm. The results obtained in our measurements show a variation with the results of other authors in different studies of osteological pieces and studies of the axis image (C2), which suggests the use of techniques and special measures for the atlantoaxial stabilization of the Mexican population in order to reduce the risk of damage to neurovascular structures.

La severidad de la artritis reumatoide como predictor oportuno de inestabilidad de la columna cervical asintomática / The severity of rheumatoid arthritis as a timely predictor of instability in the asymptomatic cervical spine

Resumen: Introducción: La afectación de la columna cervical es común en pacientes con artritis reumatoide (AR), factores de riesgo como la actividad de la enfermedad puede estar relacionada con inestabilidad cervical asintomática. Objetivo: Determinar los factores asociados a la inestabilidad de la columna cervical asintomáticos en pacientes con artritis reumatoide. Material y métodos: Estudio de casos y controles provenientes de la consulta externa de reumatología y columna de un centro de trauma de nivel II para identificar a todos los pacientes diagnosticados con AR e inestabilidad cervical asintomáticos. Con radiografías simples de la columna cervical que hacen mediciones radiográficas, se realizó el diagnóstico de inestabilidad cervical, se evaluaron los factores de riesgo como la presencia de factor reumatoide (FR), cirugías articulares previas, las elevaciones de los valores de proteína C reactiva (PCR), la severidad y actividad de la enfermedad medida en el índice de actividad de la enfermedad de 28 articulaciones (DAS 28), además del índice de actividad de la enfermedad simplificada (SDAI). Resultados: Se evaluaron 32 pacientes, nueve (28.1%) cumplieron con los criterios para inestabilidad de la columna cervical con subluxación atlantoaxial anterior (SAAa) (100%), también un paciente con SAAa presentaba subluxación vertical (SV), los factores de riesgo más relevantes: el DAS 28 con un OR = 3.54, SDA con un OR = 2.34 y por último el PCR > 1.0 su OR = 2.88. Conclusión: Los factores de riesgo asociados oportunamente en nuestra población son la severidad de la actividad de la enfermedad que podemos observar en el DAS y SDAI al aplicarlos en los pacientes y PCR > 1.0.

Abstract: Introduction: Cervical spine involvement is common in patients with RA, risk factors such as disease activity may be related to asymptomatic cervical instability. Objective: To determine the associated factors for asymptomatic cervical spine instability in patients with rheumatoid arthritis. Material and methods: Case and control study from the external spine and rheumatology consultation of a level II trauma center to identify all patients diagnosed with rheumatoid arthritis (RA) and asymptomatic cervical instability. With simple X-rays of the cervical spine, carrying out radiographic measurements, the diagnosis of cervical instability was performed, risk factors such as the presence of rheumatoid factor (FR), previous articular surgeries, elevations of the C-reactive protein (PCR) values were evaluated. The severity and activity of the disease measured in the activity index of 28 articulations (DAS 28) in addition to the index of activity of the simplified disease (SDAI). Results: We assessed 32 patients, nine patients (28.1%) met the criteria for instability of the anterior cervical spine atlantoaxial subluxation (SAAa) (100%), also one patient with SAAa presented vertical subluxation (SV), risk factors more relevant: DAS 28 with an OR = 3.54, SDA with an OR = 2.34 and finally the PCR > 1.0 its OR = 2.88. Conclusion: The risk factors associated opportunely in our population are the severity of the activity of the disease that we can see in the DAS and SDAI when applied in patients and PCR > 1.0.

Reduction and internal fixation of complex fractures of the odontoid by the transoral approach / Redução e osteossíntese de fratura complexa do odontoide por via transoral / Reducción y fijación interna de fracturas complejas de la odontoides por la vía transoral

ABSTRACT Type II odontoid fractures with irreducible posterior displacement are uncommon, and can cause spinal cord compression, respiratory failure and even death. Treatment is usually surgical, with transoral decompression and posterior fusion or with reduction and fusion of C1-C2 by the transoral approach. We describe a case of type II odontoid fracture with irreducible posterior atlantoaxial dislocation that was treated exclusively by the transoral approach with osteosynthesis of the odontoid, thus preserving functional segmental mobility. Level of Evidence III; therapeutic study.

RESUMO As fraturas do odontoide tipo II com deslocamento posterior irredutível não são comuns e podem causar compressão medular, insuficiência respiratória e até óbito. O tratamento habitualmente é cirúrgico, com descompressão transoral e fusão posterior, ou com a redução e fusão C1-C2 pela via transoral. Descrevemos um caso de fratura do odontoide tipo II, com deslocamento atlantoaxial posterior irredutível, que foi tratado exclusivamente por via transoral, com a osteossíntese do odontoide, preservando, assim, a mobilidade funcional segmentar. Nível de Evidência III; Estudo terapêutico

RESUMEN Las fracturas tipo II de la odontoides con desplazamiento posterior irreductible son poco comunes y pueden causar compresión de la médula espinal, insuficiencia respiratoria e incluso la muerte. El tratamiento suele ser quirúrgico con descompresión transoral y fusión posterior o con reducción y fusión de C1-C2 por vía transoral. Se describe un caso de fractura tipo II de la odontoides con luxación atlantoaxial posterior irreductible que fue tratada exclusivamente por vía transoral con osteosíntesis de la odontoides, preservando así la movilidad segmentaria funcional. Nivel de Evidencia III; Estudio terapéutico.

Minimally Invasive Microscope-Assisted Stand-Alone Transarticular Screw Fixation without Gallie Supplementation in the Management of Mobile Atlantoaxial Instability

STUDY DESIGN: Retrospective study. PURPOSE: To evaluate the clinico-radiological efficacy of stand-alone minimally invasive transarticular screw (MIS-TAS) fixation without supplemental Gallie fixation in the management of mobile C1–C2 instability. OVERVIEW OF LITERATURE: Data evaluating the efficacy and feasibility of MIS-TAS in the literature is scanty. METHODS: Patients with mobile atlantoaxial instability and >2 years follow-up were included and managed by stand-alone TAS fixation using the Magerl technique and morselized allograft without additional fixation. Patient demographics and intra-operative parameters were noted. Clinical parameters (Visual Analog Scale [VAS] and Oswestry Disability Index [ODI]), neurology (modified Japanese Orthopaedic Association [mJOA]), and radiological factors (anterior atlanto-dens interval and space available for cord) were evaluated pre and postoperatively. Computed tomography (CT) was performed in patients who did not show interspinous fusion on X-ray at 1 year, to verify intra-articular fusion. Statistical analysis was performed using IBM SPSS ver. 20.0 (IBM Corp., Armonk, NY, USA); the Student t-test and analysis of variance were used to assess statistical significance (p <0.05). RESULTS: A total of 82 consecutive cases (three males, one female; mean age, 36.26±5.78 years) were evaluated. In total, 163 TASs were placed. Significant improvement was noticed in clinical (mean preoperative VAS=7.2±2.19, postoperative VAS=3.3±1.12; mean preoperative ODI=78.3±4.83, postoperative ODI=34.05±3.26) and neurological features (mean preoperative mJOA=14.73±2.68, postoperative mJOA=17.5±2.21). Radiological evidence of fusion was noted in 97.5% cases at final follow-up. Seventeen patients were found to have no interspinous fusions upon X-rays, but CT revealed facet fusion in all patients except in two. Inadvertent vertebral artery injury was noted in three cases. CONCLUSIONS: Stand-alone TAS fixation with morselized allograft provides excellent radiological and clinical outcomes. The addition of a supplementary tension band and structural graft are not essential. This provides the opportunity to avoid the complications associated with graft harvesting and wiring.

Diagnosis of C2 Spondylotic Radiculopathy by Physical Examination and Imaging Studies and Treatment by Microscopic Posterior Foraminotomy: A Case Report / 대한척추외과학회지

STUDY DESIGN: Case report. OBJECTIVES: We report the case of a patient with C2 spondylotic radiculopathy who was treated by microscopic posterior foraminotomy. SUMMARY OF LITERATURE REVIEW: C2 spondylotic radiculopathy is rare, but it can occur due to spondylosis, compression by a venous plexus or vertebral artery, or hypertrophy of the atlantoepistrophic ligament. MATERIALS AND METHODS: A 64-year-old woman was hospitalized with severe occipital pain radiating toward the left cervical area and posterior to the left ear. It started 3 years previously, and became aggravated 3 months previously. Foraminal stenosis of C1-2 was observed on magnetic resonance imaging (MRI) and degenerative changes of the facet joint of C1-2 and osteophytes originating from the left atlantoaxial joint were shown on computed tomography (CT). Dynamic rotational CT showed narrowing of the left C1-2 neural foramen when it was rotated to the left. Selective C2 root block was done, but the pain was aggravated. Thus, we decompressed the C2 nerve root by microscopic posterior laminotomy of the C1 vertebra. After surgery, the patient's occipitocervical pain mostly resolved. By the 6-month follow up, pain had not recurred, and instability was not observed on plain radiographs. RESULTS: C2 Spondylotic radiculopathy was diagnosed by physical examination and imaging studies and it was treated by a surgical approach. CONCLUSIONS: C2 spondylotic radiculopathy should be considered when a patient complains of occipitocervical pain triggered by cervical rotation and C1-2 foraminal stenosis is observed on MRI and CT.