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.

Biomechanical evaluation of four surgical techniques for ventral stabilization of the atlantoaxial joint in dogs

ABSTRACT Purpose: This study compared, through biomechanical evaluation under ventral flexion load, four surgical techniques for ventral stabilization of the atlantoaxial joint in dogs. Methods: In total, 28 identical atlantoaxial joint models were created by digital printing from computed tomography images of a dog, and the specimens were divided into four groups of seven. In each group, a different technique for ventral stabilization of the atlantoaxial joint was performed: transarticular lag screws, polyaxial screws, multiple screws and bone cement (polymethylmethacrylate-PMMA), and atlantoaxial plate. After the stabilization technique, biomechanical evaluation was performed under ventral flexion load, both with a predefined constant load and with a gradually increasing load until stabilization failure. Results: All specimens, regardless of stabilization technique, were able to support the predefined load without failing. However, the PMMA method provided significant more rigidity (p ≤ 0.05) and also best resisted the gradual increase in load, supporting a significantly higher maximum force (p ≤ 0.05). There was no statistical difference in flexural strength between the transarticular lag screws and plate groups. The polyaxial screws method was significantly less resistant to loading (p ≤ 0.05) than the other groups. Conclusions: The PMMA technique had biomechanical advantages in ventral atlantoaxial stabilization over the other evaluated methods.

Axial instrument strategy for atlantoaxial dislocation with complex artery variation / 中华骨科杂志

Objective:To evaluate the axial instrument strategy for atlantoaxial dislocation with complex vertebral artery variation.Methods:A total of 55 patients with atlantoaxial dislocation who underwent surgical treatment from January 2019 to December 2021 were retrospectively analyzed, including 14 males and 41 females, aged 54.0±12.8 years (range, 22-78 years). Among these patients, 10 patients with unilateral vertebral artery high ride with contralateral vertebral artery occlusion, 30 patients with bilateral vertebral artery high ride with single dominant vertebral artery, 15 patients with bilateral vertebral artery high ride. All patients underwent posterior reduction and internal fixation. Visual analogue scale (VAS) and Japanese Orthopaedic Association (JOA) score were used to evaluate the postoperative efficacy.Results:All patients completed the surgery successfully with a follow-up time of 14.6±5.5 months (range, 6-24 months). C 2 pedicle screw fixation was performed on the non-dominant side of unilateral vertebral artery high ride and the non-dominant side of bilateral vertebral artery high ride with one dominant vertebral artery (40 vertebraes). The dominant side of unilateral high vertebral artery and bilateral high vertebral artery with one dominant vertebral artery was fixed with C 2 medial "in-out-in" screw (10 vertebraes), C 2 isthmus screw (21 vertebraes), C 2 without screw (9 vertebraes) only extended the fixed segment. For bilateral vertebral artery high ride patients, one side was used C 2 "in-out-in" pedicle screws (right 10 vertebraes, left 5 vertebraes), and the other side was fixed with C 2 medial "in-out-in" screw (8 vertebraes), C 2 isthmus screw (5 vertebraes), C 2 without screw only extended the fixed segment (2 vertebraes). The JOA scores were 8.5±1.8, 13.9±1.3, and 14.4±1.1 preoperatively, 6 months postoperatively, and at the final follow-up, respectively, with statistically significant differences ( F=279.40, P<0.001). JOA at 6 months postoperatively and at the final follow-up was greater than preoperatively, and the differences were statistically significant ( P<0.05), whereas the differences in JOA scores at 6 months postoperatively and at the final follow-up was not statistically significant ( P>0.05). Preoperative, 6 months postoperatively and final follow-up cervical VAS scores were 3.7±1.9, 2.1±0.9 and 1.6±1.0, respectively, with statistically significant differences ( F=39.53, P<0.001). The cervical VAS at 6 months postoperatively and at the last follow-up was less than that before surgery, and the differences were statistically significant ( P<0.05). Cervical VAS scores at 6 months postoperatively were greater than at the last follow-up, with a statistically significant difference ( P<0.05). Conclusion:For patients with atlantoaxial dislocation with complex vertebral artery variation, C 2 lateral "in-out-in" screw, C 2 medial "in-out-in" screw, isthmus screw fixation or C 2 without screw only extended the fixed segment can obtain good clinical efficacy.

Research progress of Chiari malformation type I and atlantoaxial instability / 中华骨科杂志

Chiari malformation (CM) is a group of congenital cerebellar tonsillar hernia malformations involving the craniocervical junction. Chiari malformation type I (CMI) is the most common in clinic, however its pathogenesis is still unclear, and there is no consensus on the surgical treatment standard of CMI. At present, the most widely accepted is the theory of posterior fossa incompatibility, so doctors at home and abroad use posterior fossa decompression (PFD) and posterior fossa compression with duraplasty (PFDD) as the gold standard for surgical treatment, and have their own experience and technical improvement. However, the volume of the posterior cranial fossa in some patients is no different from that in healthy people, and about 30% of the patients with CMI have poor results after posterior cranial fossa decompression. As a result, this operation cannot treat all patients with CMI. In recent years, with the development of imaging, the progress of diagnostic technology and the deepening of understanding of CM, some studies have shown that CMI may be related to atlantoaxial instability, and proposed that CMI is the secondary factor of atlantoaxial instability, and atlantoaxial fusion is the standard of surgical treatment, which has caused great controversy in academic circles. Different clinical research results of scholars support or oppose this theory: some studies have shown that the clinical symptom relief rate of patients with CMI treated with atlantoaxial fusion is 96.9%; another study showed that 70% of patients with CMI underwent atlantoaxial fusion had improved neurological function, but the overall postoperative effect was not satisfactory. In short, CMI is related to many diseases and its clinical manifestations are complex. Therefore, individualized management and treatment should be carried out in combination with the clinical manifestations and auxiliary examination results of patients.

Study on radiation dose and image quality differences between cone-beam CT and multi-slice spiral CT for atlantoaxial spine imaging / 中华放射医学与防护杂志

Objective:To compare the differences in radiation dose and image quality between cone-beam CT (CBCT) and multi-slice spiral CT (MSCT) applied to atlantoaxial spine imaging.Methods:Head and neck phantom was scanned at 30 exposure parameter combinations using Pramerica CBCT scanner and 15 parameter combinations using Toshiba 320-row MSCT. The effective dose ( E) of CBCT was calculated based on the Monte Carlo dose estimation software PCXMC, the E value of MSCT was obtained by multiplying the dose length product (DLP) by the related factor. t-test for two independent samples or Wilcoxon rank sum test were used for comparison of radiation dose and subjective and objective image quality between two modalities. The subjective evaluation was a 5-point subjective scale using double-blind method for edge sharpness, contrast, soft tissue level, and artifacts of the images. The signal and noise in the region of interest (ROI) were measured and the contrast signal-to-noise ratio (CNR) was calculated. Results:For radiation dose, the volumetric dose index and E values of 2.9 mGy and 27.61 μSv for CBCT were lower than those of 8.8 mGy and 433.16 μSv for MSCT, and the differences were statistically significant( z=-3.05, -5.25, P<0.05). For objective evaluation of image quality, the noise and CNR were 27.74 HU and 3.69 in CBCT group, 7.84 HU and 27.1 in MSCT group. The difference between them were statistically significant( z=-5.39, -5.42, P<0.05). The overall image quality, contrast and artifact scores of the CBCT group were 3.5, 3.0 and 5 were higher than those of the MSCT group at 2.0, 2.0, and 4.0, respectively ( z=-2.32, -2.46, -3.31, P<0.05). Conclusions:Both atlantoaxial CBCT and MSCT scans provide image quality that meets diagnostic requirements. Compared to MSCT, CBCT atlantoaxial scans can effectively reduce radiation dose according to the principle of optimization of radiation protection.

Efficacy evaluation of cluster nursing in robot-assisted surgery for the treatment of reducible atlantoaxial dislocation / 中华创伤杂志

Objective:To explore the effect of cluster nursing in robot-assisted surgery for the treatment of reducible atlantoaxial dislocation.Methods:A retrospective cohort study was conducted to analyze the clinical data of 41 patients with reducible atlantoaxial dislocation treated by robot-assisted surgery in Honghui Hospital affiliated to Xi′an Jiaotong University from January 2019 to December 2021, including 28 males and 13 females; aged 18-79 years [(45.2±10.3)years]. Ninteen patients received cluster nursing (cluster nursing group), with operating room nursing team set up on the basis of routine nursing and performed cluster nursing in line with evidence-based medicine. Twenty-two patients received routine nursing (routine nursing group). The operation time, intraoperative blood loss, frequency of intraoperative C-arm fluoroscopy, time of drainage tube placement and chief surgeon′s satisfaction for nursing were compared between the two groups. The degree of pain was evaluated by pain numerical score (NRS) at 12 hours, 24 hours, 48 hours, 72 hours, 1 month and 3 months after operation and at the last follow-up. The neck disability index (NDI) was assessed at 1 day before operation, 1 month after operation, 3 months after operation and at the last follow-up. The complications were observed.Results:All patients were followed up for 12-18 months [(16.7±3.7)months]. The operation time, intraoperative blood loss, frequency of C-arm fluoroscopy and time of drainage tube placement in cluster nursing group were (82.9±10.4)minutes, (105.9±11.8)ml, (3.8±0.6)times and (1.5±0.4)days, while those in routine nursing group were (125.7±12.8)minutes, (208.4±13.8)ml, (9.7±2.3)times and (3.6±0.6)days, respectively (all P<0.01). The chief surgeon′s satisfaction for nursing was 94.7% (18/19) in cluster nursing group and was 68.2% (15/22) in routine nursing group ( P<0.05). The NRS in cluster nursing group was (6.2±0.4)points, (6.0±0.7)points, (4.9±1.1)points, (2.7±0.5)points, (1.9±0.4)points, (1.8±0.4)points and (1.5±0.3)points at 12 hours, 24 hours, 48 hours, 72 hours, 1 month and 3 months after operation and at the last follow-up, while it was (7.6±0.6)points, (6.8±1.2)points, (5.8±1.5)points, (4.2±0.8)points, (3.4±0.7)points, (2.6±0.5)points and (2.2±0.5)points in routine nursing group ( P<0.05 or 0.01). There was no significant difference in the NDI between the two groups at 1 day before operation, but the NDI in cluster nursing group was 20.6±4.5, 14.6±2.8 and 10.7±2.5 at 1 month and 3 months after operation and at the last follow-up, while it was 26.9±4.1, 18.7±3.3 and 13.7±1.7 in routine nursing group (all P<0.01). There was no hematoma, infection or implant-related complications in both groups .Conclusion:For robot-assisted surgery in the treatment of reducible atlantoaxial dislocation, cluster nursing is associated with shortened operation time and time of drainage tube placement, decreased intraoperative blood loss and frequency of intraoperative fluoroscopy, increased chief surgeon′s satisfaction for nursing, reduced pain and accelerated functional recovery.

Characterization of Alar Ligament in Young Adult on 3.0T MRI: A Cross-sectional Study in IIUM Medical Centre, Kuantan

@#Introduction: Alar ligament is a paired craniocervical junction ligaments which stabilizes the atlantooccipital and atlantoaxial joints. The main purpose of the study was to compare the normal anatomy of alar ligament on MRI between male and female. The prevalence of alar ligament visualized on MRI and its characteristics were also studied apart from determining the association between the heights of respondents with alar ligament signal intensity and dimensions. Methods: Fifty healthy volunteers were studied using 3.0T MR scanner (Siemens Magnetom Spectra) by 2-mm proton density, T2 and fat-suppression sequences. Alar ligament visualization, dimensions and variability of the ligament courses, shapes and signal intensity characteristics were determined. Results: The orientation of the ligament was laterally ascending in most of the subjects (60%), predominantly oval in shaped (54%) and 67% showed inhomogenous signal. Females are 70% less likely to exhibit alar ligament signal inhomogeneity than males. There were positive correlation between height and the craniocaudal diameter of the alar ligament as well as the anteroposterior diameter, which were statistically significant (r = 0.25, n = 100, p = 0.01 and r = 0.201, n = 100, p = 0.045 respectively). Conclusion: Tremendous variability of alar ligament shows that clinical and multimodality correlation needs to be exercised, especially in evaluating alar ligament MR signal in male. Taller individuals otherwise tend to have longer and thicker ligaments. Future studies with larger samples of alar ligaments including trauma cases are also recommended to supplant a new classification system of alar ligament injury.

Biomechanical Study on Atlantoaxial Dislocation Combined with Basilar Invagination by Different Posterior Internal Fixation Methods / 医用生物力学

Objective To investigate biomechanical differences of two posterior occipitocervical internal fixation techniques for treating basilar invagination with atlantoaxial dislocation (BI-AAD). Methods Intra-articular cage + posterior occipital plate+C2 pedicle screw (Cage+C2PS+OP), and intra-articular cage+C1 lateral mass screw+C2PS (Cage+C1LMS+C2PS) models were established based on occipitocervical CT data of the BI-AAD and clinical operation scheme, and the stability of atlantoaxial joint and stress distribution characteristics of C2 endplate and implanted instruments under different motion states were analyzed. Results Compared with the Cage+C1LMS+C2PS model, the atlantoaxial range of motion ( ROM) under flexion, extension, lateral bending and axial rotation in the Cage+C2PS+OP model were reduced by 5. 26% , 33. 33% , 43. 75% , -5. 56% , and stress peak of screw-rod fixation system were reduced by 47. 81% , 60. 90% , 48. 45% , 39. 14% , respectively. Under two internal fixation modes, stresses of C2 endplate and cage were mainly distributed on the compressive side during the motion, and both the screw-bone interface and the caudal side of screw subjected to large loading. Conclusions Two internal fixation methods could provide similar stability. However, the stress concentration of screw-rod system was more obvious and the possibility of screw loosening and fracture was greater under Cage+ C1LMS+C2PS fixation.

The Short-term Effectiveness of Three Manipulations for Atlantoaxial Joint Disorders and the Effects on Surface Electromyography of Sternocleidomastoid Muscle / 中医杂志

ObjectiveTo compare the short-term effectiveness of the three different manipulations for atlantoaxial joint disorders and their effects on surface electromyography of sternocleidomastoid muscle. MethodsNinty patients with atlantoaxial joint disorders were randomly divided into the tendon relaxing manipulation group， the tendon relaxing plus rehabilitation manipulation group， and the conventional manipulation group， with 30 cases in each group， and each group of patients received the corresponding manipulation treatment for 2 weeks. The changes of visual analogue score （VAS） of occipital neck pain， evaluation scale for cervical vertigo （ESCV）， and averaged electromyography （AEMG） of surface electromyography of bilateral sternocleidomastoid muscles before and after the treatment were observed， and the clinical effectiveness and safety of the patients were compared among groups. ResultsThe VAS scores of patients in each group decreased， and the ESCV scores increased after treatment （P＜0.01）， and the tendon relaxing manipulation group and the tendon relaxing plus rehabilitation manipulation group were significantly better than the conventional manipulation group （P＜0.01）. The AEMG of the bilateral sternocleidomastoid muscles of the three groups increased after treatment （P＜0.01）； when compared among the three groups， the AEMG of the bilateral sternocleidomastoid muscles of the tendon relaxing plus rehabilitation manipulation group was higher than that of the tendon relaxing manipulation group， and the tendon relaxing manipulation group was higher than that of the conventional manipulation group （P＜0.05 or P＜0.01）. The cure and markedly effective rates of the tendon relaxing manipulation group， the tendon relaxing plus rehabilitation manipulation group， and the conventional manipulation group were 56.67%， 86.67%， and 36.67% respectively， showing statistically difference （K=10.21， P＜0.01）. ConclusionThe tendon relaxing manipulation and tendon relaxing plus rehabilitation manipulation can effectively improve the symptoms of vertigo， headache， and neck pain for patients with atlantoaxial joint disorders， and can improve the contraction function of sternocleidomastoid muscle， whose effectiveness are better than that of conventional manipulation.

Research Progress on the Application of Goel Technique in Craniovertebral Junction Anomalies / 中国医学科学院学报

Craniovertebral junction anomalies are a group of diseases characterized by the pathological changes of occipital bone,atlantoaxial bone,cerebellar tonsil,surrounding soft tissue,and nervous system,which are caused by a variety of factors.Chiari malformation is a common type of craniovertebral junction anomalies,the conventional surgical therapy of which is posterior fossa decompression.Currently,scholars represented by Goel have proposed a new theory on the classification,pathogenesis,and treatment of Chiari malformation based on posterior atlantoaxial fixation (Goel technique).This article introduces the progress in Goel technique,aiming to provide reference for the clinical work.

Artritis reumatoide de la columna cervical: aspectos clave para el cirujano ortopédico / Rheumatoid arthritis of the cervical spine: key aspects for the orthopedic surgeon

La artritis reumatoide es una enfermedad inflamatoria autoinmune crónica que afecta con frecuencia a la columna cervical. El diagnóstico clínico de la afección cervical puede ser difícil; por lo tanto, se recomienda la evaluación radiográfica sistemática de todos los pacientes. El tratamiento oportuno de estas lesiones es importante para preservar la independencia, la función neurológica, e, incluso, la vida de los pacientes. Este artículo es una revisión actualizada de todos los aspectos de la artritis reumatoide de la columna cervical relevantes para el cirujano ortopédico.

Rheumatoid arthritis is a chronic inflammatory autoimmune disease that frequently affects the cervical spine. The clinical diagnosis can be difficult; therefore, a systematic radiographic evaluation of all patients is recommended. The timely treatment of these lesions is important to preserve the self-reliance, the neurological function, and even the lives of the patients. The present article is an update of all the aspects pertaining to cervical spine rheumatoid arthritis that are relevant to the orthopedic surgeon.

Fijación con tornillos transarticulares C1-2 combinada con técnica de Gallie en luxación atloaxoidea / C1-2 transarticular screw fixation combined with Gallie technique in atloaxial dislocation

RESUMEN Introducción: existen múltiples técnicas quirúrgicas para tratar la inestabilidad del complejo atlantoaxial. La fijación con tornillos transarticulares C1-2 (técnica de Magerl) ha mostrado altos índices de fusión, y puede ser combinada con los sistemas de alambrado descritos inicialmente, para garantizar mayor estabilidad al constructo. Presentación de caso: masculino, 62 años, que luego de una caída de dos metros, es traído a la institución con dolor cervical y con imposibilidad para mover las extremidades. Al examen neurológico, presentaba un grado B en la American Spinal Injury Classiffication Scale. Se diagnostica fractura odontoidea conminuta y luxación atloaxoidea. Se le aplica tracción cervical con lo que se logra la alineación vertebral. Se planifica tratamiento quirúrgico mediante técnica de Magerl. Ante trayectoria subóptima del tornillo inicial, se combina con fusión atloaxoidea posterior, mediante técnica de Gallie. Se mantuvo inmovilización externa durante dos semanas. Al egreso hospitalario, el paciente logra la deambulación, aunque con disparesia braquial con predominio distal. En estudios radiológicos evolutivos, no se observa fallo del sistema de instrumentación. Conclusiones: en este caso la utilización de la técnica de Gallie, ante la malposición de uno de los tornillos transarticulares C1-2, permitió conservar la estabilidad del constructo.

ABSTRACT Introduction: Multiple surgical techniques exist to treat instability of the atlantoaxial complex. Transarticular C1-2 screw fixation (Magerl's technique) has shown high fusion rates, and can be combined with the initially described wiring systems to guarantee greater stability to the construct. Case presentation: male, 62 years old, who after a two-meter fall, was brought to the institution reporting cervical pain and inability to move the limbs. On neurological examination, he had a grade B on the American Spinal Injury Classiffication Scale. A comminuted odontoid fracture and atloaxial dislocation were diagnosed. Cervical traction was applied and vertebral alignment was achieved. Surgical treatment was planned using Magerl's technique. Given the suboptimal trajectory of the initial screw, it was combined with posterior atloaxoid fusion, using Gallie technique. External immobilization was maintained for two weeks. At hospital discharge, the patient achieved ambulation, maintaining brachial dysparesis with distal predominance. In evolutionary radiological studies, no failure of the instrumentation system was observed. Conclusions: In our case, the use of the Gallie technique, in view of the malposition of one of the C1-2 transarticular screws, allowed preserving the stability of the construct.

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.

Effects of traction therapy on atlantoaxial joint dislocation-induced cervical vertigo

Cervical vertigo is a common complication of atlantoaxial joint dislocation. However, there is no consensus on the effects of different therapies on the recovery of the patients suffering cervical vertigo. The objective of this randomized controlled trial was to investigate the effect of traction therapy on reducing cervical vertigo induced by atlantoaxial joint dislocation. A total of 96 patients were randomized to receive traction therapy or traditional therapy for two weeks. The overall clinical efficacy was measured based on the 30-point cervical vertigo symptom and function evaluation form. The therapeutic effects were also evaluated based on lateral atlantodental space (LADS), vertigo scale, neck and shoulder pain scale, headache scale, daily life and work scale, psychosocial adaptation scale, and quality of life. Compared with the traditional therapy group, the traction group demonstrated markedly higher overall clinical efficacy (P=0.038). Both the traction therapy group and the traditional therapy group showed significant decrease in LADS (P<0.001), but the traction therapy group had a greater reduction of LAD compared with the traditional group (P<0.01). Traction therapy consistently led to significantly greater relief of cervical vertigo symptoms, including dizziness, neck and shoulder pain, headache, inconvenience in daily living and work activities, impaired psychosocial adaptation, while improving quality of life. The efficacy of traction therapy for cervical vertigo surpasses that of traditional therapy, suggesting that traction therapy is potentially more clinically useful in treating these patients.

Locked-in syndrome after traumatic atlantoaxial subluxation: a case report / Síndrome do encarceramento decorrente de subluxação atlantoaxial traumática: relato de caso / Síndrome de enclaustramiento por subluxación atlantoaxoidea traumática: informe de caso

ABSTRACT Traumatic atlanto-axial subluxation is a rare and underdiagnosed condition due to its high rate - reported to be between 60 and 80% - of early mortality. Its diagnosis takes into account the trauma mechanism, precise analyses of the imaging tests and the clinical presentation of the patient. This article describes a rare presentation of atlanto-axial subluxation associated with craniocervical dislocation as a case of locked-in syndrome. Level of evidence V; Retrospective observational study - Case report.

RESUMO Subluxação atlantoaxial traumática é uma condição de diagnóstico raro e subestimado, devido a sua alta taxa - descrita entre 60% e 80% - de mortalidade precoce. Seu diagnóstico leva em conta o mecanismo do trauma, as análises precisas dos exames de imagem e a apresentação clínica do paciente. Este artigo relata um quadro raro de subluxação atlantoaxial associada à luxação craniocervical como um caso de síndrome do encarceramento. Nível de evidência V; Estudo observacional retrospectivo - Relato de caso.

RESUMEN La subluxación atlantoaxoidea traumática es una afección rara y subdiagnosticada debido a su alta tasa - descrita entre el 60 y el 80%-de mortalidad temprana. Su diagnóstico tiene en cuenta el mecanismo del traumatismo, los análisis de imagen precisos y la presentación clínica del paciente. Este artículo informa de una rara condición de subluxación atloaxoidea asociada a una dislocación craniocervical como un caso de síndrome de enclaustramiento. Nivel de evidencia V; Estudio observacional retrospectivo - Informe de caso.

Imaging study of simple Chiari malformation type I and atlantoaxial instability / 中华骨科杂志

Objective:To investigate the relationship between simple Chiari malformation type I (CMI) and atlantoaxial instability from the imaging point of view.Methods:A retrospective analysis were performed on 46 patients diagnosed with simple CMI from January 2014 to December 2020. Forty-six normal people matched for age and sex were selected as the normal control group, while 30 patients with atlantoaxial dislocation were selected as the dislocation group. The degree of atlantoaxial joint degeneration in each group was assessed according to Weishaupt degeneration grading; the atlantoaxial joint angulation angle was measured in the control group of patients with simple CMI; and the sagittal imaging parameters of cervical spine X-ray were measured, including C 0-C 1 Cobb angle, C 0-C 2 Cobb angle, C 1-C 2 Cobb angle, C 1-C 7 Cobb angle, C 2-C 7 Cobb angle, C 7 Slope, C 2 Tilt, spino cranial angle (SCA), and C 2-C 7 sagittal vertebral axis (SVA). All radiographic parameters were measured twice independently by two spine surgeons, and intraclass correlation coefficient (ICC) were determined to demonstrate intra- and inter-observer reliability. Results:ICC ranged between 0.842 and 0.974 in the current study, demonstrating "excellent" reliability of radiographic measurements. No significant difference was noted regarding age and the distribution of genders among the three groups. There were significant differences in the distribution of Weishaupt degeneration grading of atlantoaxial joints between simple CMI, normal and dislocation group ( H=53.68, P<0.001 on the left side; H=43.39, P<0.001 on the right side). There were significant differences in the degree of atlantoaxial joint degeneration between the normal group and dislocation group (left, Z=6.60, P<0.001; right, Z=6.29, P<0.001); There were significant differences in the degree of atlantoaxial joint degeneration between the normal group and simple CMI patients (left, Z=5.31, P<0.001; right, Z=4.13, P<0.001); There were significant differences in the degree of atlantoaxial joint degeneration between simple CMI and dislocation group (left, Z=3.20, P=0.001; right, Z=3.15, P=0.002). There were significant difference in the angulation angle of the atlantoaxial articular surface between the normal group and simple CMI patients (left, Z=3.32, P<0.001; right, Z=5.74, P<0.001). There were significant differences in C 0-C 1 Cobb angle ( t=2.41, P=0.018), C 1-C 7 Cobb angle ( t=2.88, P=0.005), C 2-C 7 Cobb angle ( t=3.29, P=0.001), and C 2-C 7 SVA ( t=2.87, P=0.005) between the normal group and simple CMI patients, but there was no significant difference in other parameters. Conclusion:The degree of atlantoaxial joint degeneration in patients with simple CMI is higher than that in normal people, the angulation angle is larger, and the cervical lordosis is larger, suggesting that there may be atlantoaxial joint instability. This study provides further evidence that Chiari malformation type I is associated with atlantoaxial instability.

Surgical strategies of atlantoaxial dislocation in mucopolysaccharidosis IVa / 中华骨科杂志

Objective:To discuss the surgical strategies of atlantoaxial dislocation in children with mucopolysaccharidosis IVA.Methods:8 cases of atlantoaxial dislocation in children with mucopolysaccharidosis IVA treated with posterior atlantoaxial reduction, decompression, bone graft and internal fixation from April, 2019 to October, 2020 were retrospectively analyzed, including 6 males and 2 females, aged 6.2±3.1 years (range, 2-10 years). All the 8 children had lower limb weakness and walking instability, and some of them could not even stand and walk, and all of them had odontoid hypoplasia, atlantoaxial dislocation and systemic skeletal dysplasia. Measures, including American Spinal injury Association (ASIA) grade, modified atlanto-dental interval (mADI) and reduction rate, screw placement type and fusion of bone graft, were recorded and analyzed.Results:The follow-up time was 17.8±7.4 months (range, 8-27 months). The total operation time was 144.0±43.1 mins (range, 90-220 min) and the blood loss during the surgery was 89.1±55.1 ml (range, 15-180 ml). The ASIA grade were 3 cases of "C" level, 4 cases of "D" level and 1 case of "E" level before the operation, and 1 case of "C" level, 1 case of "D" level and 6 cases of "E" level at the latest follow-up. The mADI reduced from 7.38±2.62 mm pre-surgery to 2.50±1.60 mm ( t=5.71, P=0.001). The reduction rate of the latest follow-up mADI was 65.0%±26.3%. 31 pedicle screws were inserted, including 26 Type I screws (83.9%), 4 Type II screws (12.9%) and 1 Type III screw (3.2%), and no injury of spinal cord or blood vessels were observed associated with the Type III screw. One unilateral axial lamina screw was used in 1 case. 5 patients showed fusion (autogenous bone) 6 months after the surgery, 2 patients got fusion (allogeneic bone) 1 year after the surgery, and other patients showed bone graft resorption (allogeneic bone) at the latest follow-up. One patient developed type II respiratory failure on the night of operation and recovered after rescue. Other patients had no complications such as vascular and nerve injury, screw loosening and so on. Conclusion:The majority of children with type IVa mucopolysaccharidosis are accompanied by absence of odontoid process. If such children are complicated with atlantoaxial dislocation and cervical spinal canal stenosis resulting in cervical spinal cord injury, timely surgical intervention should be carried out. Posterior atlantoaxial fusion is a safe and effective surgical method. As children have the characteristics of multi-system involvement, multi-disciplinary cooperation may be needed to ensure perioperative safety.

Cervical anterior approach atlantodentoplasty for the treatment of irreducible atlantoaxial dislocation complicated with bony abnormality of atlanto-dental joint / 中华骨科杂志

Objective:To evaluate the clinical efficacy of cervical anterior approach atlantodentoplasty for the treatment of irreducible atlantoaxial dislocation complicated with bony abnormality of atlanto-dental joint.Methods:Retrospective analysis was conducted to study the clinical data of 31 patients with irreducible atlantoaxial dislocation complicated with bony abnormality of atlanto-dental joint, including 7 males and 24 females; age ranged from 23 to 74 years, with an average of 49.0±12.0 years. All patients underwent cervical anterior approach soft tissue release, atlantodentoplasty and one-stage posterior occipito-cervical fixation and fusion. Twenty-one patients with atlantodental osteoarthritis underwent simplex atlantodental osteophyte resection, 5 patients with anterior tubercle hypertrophy of atlas and 5 patients with anterior tubercle hypertrophy of atlas and atlantodental osteoarthritis underwent atlantodental osteophyte resection and partial anterior tubercle resection. The operation time and blood loss of anterior procedure and total procedure were recorded. The anterior tubercle thickness (ATT), the atlantodental interval (ADI)were recorded before and 1 week after the operation. The available space of the cord (SAC), clivus-canal angle (CCA), cervicomedullaryangle (CMA), and the Japanese Orthopaedic Association (JOA) scores were recorded before the operation, 1 week, 3 months and 12 months after the operation, and at the last follow-up. The JOA improvement rate at the last follow-up was calculated, the time of postoperative bone graft fusion was recorded, and the complications were observed.Results:All patients were followed up for 12-60 months, with an average of 34.5±13.8 months. The operation time of anterior cervical atlantodentoplasty was 120.9±15.9 min, and the overall operation time was 315.1±31.4 min; The blood loss of anterior procedure was 101.2±31.2 ml, and that of overall procedure was 372.7±56.0 ml. The one week postoperative ATT (7.4±1.6 mm) of patients with anterior tubercle partial resection of atlas was lower than that before operation 10.8±1.5 mm ( t=4.94, P=0.001). The one week postoperative ADI 0.9±1.2 mm decreased compared with the preoperative ADI 8.3±2.2 mm ( t=17.91, P<0.001). The preoperative SAC was 10.4±2.8 mm, which increased to 19.2±3.6 mm one week after operation and 19.4±3.7 mm ( F=41.31, P<0.001) at last follow-up. The preoperative CCA was 119.4°±17.9°, which increased to 142.6°±13.0° one week after operation and 141.6°±12.2° ( F=35.86, P<0.001) at last follow-up. The preoperative CMA was 121.7°±14.1°, which increased to 148.9°±9.4° one week after operation and 149.4°±9.0° ( F=52.07, P<0.001) at last follow-up. The preoperative JOA score was 12.0±2.6, which was 14.3±1.3 one week after operation and 15.9±1.0 ( F=23.81, P<0.001) at last follow-up. JOA improvement rate was 78.9%±17.1%, while 23 cases were excellent (74.2%), 8 cases were good (25.8%), and the excellent and good rate was 100%; Thd fusion time of grafted bone was 5.7±1.5 months with the fusion rate of 100%; There were 12 patients with dysphagia after operation, all of which relieved spontaneously 5-10 days after operation; There were 3 cases of irritating choking after drinking or eating, and 2 cases were gradually alleviated 3-5 days after operation. One case was complicated with aspiration pneumonia due to stubborn choking, which gradually alleviated after 1 month of nasal feeding. No hardware failure or reduction loss, no serious complications such as esophageal injury, cerebrospinal fluid leakage, incision infection or vertebral artery injury occurred. Conclusion:Cervical anterior approach atlantodentoplasty for the treatment of irreducible atlantoaxial dislocation complicated with bony abnormality of atlanto-dental joint can anatomically reduce the atlantoaxial joint, and the clinical effect is satisfactory.

Transoral stepped atlantoaxial release theory for irreducible atlantoaxial dislocation / 中华骨科杂志

Objective:To investigate the clinical efficacy of different grade transoral atlantoaxial release for the treatment of irreducible atlantoaxial dislocation.Methods:From January 2010 to December 2019, 297 patients with irreducible atlantoaxial dislocation treated by different grade releases were retrospectively analyzed, including 132 males and 165 females, aged 42.3±12.14 years (range, 10-63 years). All cases were treated by different grade releases, Grade I (196, 66.0%), Grade II (54, 18.2%), Grade III (28, 9.4%) and Grade IV (19, 6.4%). The American Spinal Injury Association (ASIA) grade and Japanese Orthopedic Association (JOA) score were recorded as the clinical evaluation index. The clivus-canal angle (CCA) and cervico-medullary angle (CMA) were measured to evaluate the reduction. The surgery time, blood loss, duration of bony fusion and complications were also analyzed.Results:The follow-up time was 14.8±10.2 months (range, 9-36 months). The surgery time of Grade I-IV were 2.02±0.35 min, 3.00±0.36 min, 4.07±0.96 min and 5.24±0.83 min, respectively ( F=385.43, P<0.001), blood loss was 84.08±27.21 ml, 153.61±31.36 ml, 268.93±48.94 ml and 444.21±109.51 ml, respectively ( F=582.39, P<0.001). The preoperative ASIA motor score of Grade I-IV were 83.85±6.68, 84.06±5.47, 84.07±5.99 and 85.00±4.11, respectively. The last follow-up were 98.34±2.38, 98.67±1.79, 98.86±1.58 and 98.32±2.11, respectively, with statistically significant differences from preoperative ( P<0.05). The preoperative JOA score of Grade I-IV were 11.44±1.73, 11.59±1.72, 11.61±1.47 and 11.32±1.80, respectively. The last follow-up were 16.22±1.00, 16.28±1.02, 16.14±1.04 and 16.16±1.07, respectively, with statistically significant differences from preoperative ( P<0.05). The preoperative CCA of Grade I-IV were 110.19°±8.76°, 112.48°±7.66°, 106.61°±6.54° and 109.05°±7.79°, respectively. The last follow-up were 140.22°±8.04°, 141.86°±7.04°, 142.35°±8.62° and 140.15°±6.49°, respectively, with statistically significant differences from preoperative ( P<0.05). The preoperative CMA of Grade I-IV were 113.48°±9.54°, 116.03°±8.38°, 109.55°±7.13°, and 112.46°±8.33°, respectively. The last follow-up were 144.28°±7.75°, 146.40°±6.98°, 145.81°±8.27° and 143.24°±6.36°, respectively, with statistically significant differences from preoperative ( P<0.05). Solid bony fusion was obtained except for 3 cases, the fusion time was 9.71±2.55 months (range 3-14 months). Altogether 33 complications occurred in all cases (11.1%), including 3 fusion failure, 3 cerebrospinal leak, 3 wound infection, 2 death (1 case caused by cerebrospinal leak), 11 pharyngeal discomfort, 4 postoperative pain surrounding iliac crest, and 8 malunion of iliac crest. Conclusion:Transoral stepped atlantoaxial release theory could provide guidelines for atlantoaxial dislocation treatment, and make the transoral release technique more effective and safer.

Prevalence and radiographic morphology of atlantoaxial dislocation in Kashin-Beck disease / 西安交通大学学报(医学版)

【Objective】 Until now, most clinical and basic studies on Kashin-Beck disease (KBD) have focused on the visible deformed extremities, and there is a lack of reports concerning their spinal features, especially for the atlantoaxial joint. The purpose of this study was to determine the prevalence and radiographic features of atlantoaxial dislocation (AAD) in KBD in adult patients. 【Methods】 The prevalence and radiographic features of AAD were determined by the basic information collected, clinical symptoms, and lateral and dynamic plain radiography in 111 KBD patient and 120 non-KBD participants. In the KBD group, AAD and non-AAD patients were compared in age, gender, height, weight, BMI, smoking history, chronic history, disease duration and grade of disease so as to identify the related factors of the occurrence of AAD. 【Results】 Symptoms at the neck or neurological manifestations were present in 17.5% (21/120) in the non-KBD population and 39.6% (44/111) patients with KBD. AAD case was not detected in the non-KBD population, while in 16.2% (18/111) of KBD patients in the endemic area. The prevalence was higher in the KBD patients than in the non-KBD population, and there was a significant difference in the detection rate of AAD between the two groups (χ2=21.10, P<0.001). Plain radiography demonstrated that there were 10 (55.6%) cases with separation of the odontoid process and the other 8 (44.4%) cases with hypoplasia of odontoid process. Anterior AAD was noted in 12 (66.7%) patients and posterior AAD in 6 (33.3%) cases based on the displacement direction, while 16 (88.9%) cases were reducible and 2 (11.1%) cases were irreducible on the basis of the reducibility. Comparing the 93 patients with non-AAD KBD patients and 18 patients with AAD patients, there was no significant difference in age, sex, BMI, history of medical disease or smoking (all P>0.05). There were significant differences in height, weight, disease duration and grade of disease between AAD and non-AAD patients (all P<0.05). 【Conclusion】 KBD can cause the occurrence of atlantoaxial dislocation by inducing separation or hypoplasia of the odontoid process. This research may provide clinical evidence for screening, earlier prevention and treatment of atlantoaxial dislocation in adult KBD patients.