Atlantoaxial Research Articles

Stress Maneuver for Basilar Invagination Reduction: A Technical Report

BackgroundBasilar invagination (BI) is a prolapse of the odontoid process cranially and posteriorly towards the foramen magnum. Several surgical treatment options are available for this condition. Herein, we describe a stress maneuver technique for BI reduction using a single-stage posterior approach. MethodsWe described the case of a 56-year-old male diagnosed with type A BI and brainstem compression, who was treated with posterior fossa decompression and occipitocervical fusion. The BI was reduced intraoperatively using a stress maneuver, and cranial traction or atlantoaxial joint distraction was not necessary. ResultsPostoperative imaging revealed a reduction of the odontoid process and adequate brainstem decompression. The patient showed progressive improvement of his symptoms. ConclusionIn selected cases, stress maneuvers for BI reduction can be a less morbid, easier, and replicable option within the already existing technical arsenal.

Two-Stage surgical approach for type III odontoid fracture with C1-C2 fracture dislocation: A case report and management overview

Introduction and Importance: Odontoid fractures of the second cervical vertebra (C2) are categorized into three types, with type III extending into the body of the axis. These fractures, often resulting from high-energy trauma, can cause significant instability and neurological issues. This case report discusses a 43-year-old male with a type III odontoid fracture and C1-C2 fracture dislocation, demonstrating the effectiveness of traditional neurosurgical techniques in managing such complex injuries. Case Presentation: A 43-year-old male presented with upper cervical pain and right upper limb weakness following a road traffic accident. Imaging revealed a type III odontoid fracture with posterior displacement and atlanto-axial (C1-C2) joint dislocation. The patient underwent a two-stage surgical procedure. The first stage involved transoral decompression to address the retropulsed odontoid fragment and relieve spinal cord compression. The second stage involved posterior craniocervical fixation using an autologous iliac bone graft for stabilization. The patient showed postoperative improvement and was discharged on the third day, with a stable condition at a one-month follow-up. Clinical Discussion: Managing type III odontoid fractures with C1-C2 dislocation is challenging, requiring a strategic approach to ensure spinal stability and neurological recovery. Transoral decompression provides direct access for effective decompression, while posterior fixation ensures robust stabilization. The use of an autologous iliac bone graft enhances fusion and long-term stability. This case illustrates the successful integration of traditional neurosurgical techniques with modern surgical principles. Conclusion: This case underscores the importance of traditional neurosurgical techniques in managing complex odontoid fractures. The two-stage approach of transoral decompression followed by posterior craniocervical fixation proved effective, highlighting the relevance of these techniques in achieving positive outcomes in contemporary neurosurgical practice.

C1-ring оsteosynthesis as a functionally preserving operation for unstable atlas fractures

Objective. To analyze the dynamics of pain syndrome, quality of life and functional status of patients with unstable atlas fractures after C1-ring osteosynthesis.Material and Methods. Study design: observational retrospective case series study (n = 15). The intensity of pain syndrome was assessed using the VAS scale before surgery, 3 days, and 3 and 6 months after surgery. The quality of life was assessed using the Neck Disability Index (NDI) before surgery, and 3 and 6 months after surgery. Functional status, as well as cervical spine range of motion (head turn left/right, flexion/extension) was assessed 3 and 6 months after surgery. The integrity of the atlas bone ring and the degree of fusion after fixation were assessed using axial CT scans; and the lateral mass separation was assessed using frontal CT scans. The criterion for transverse ligament injury was a separation of lateral masses of more than 8.1 mm. Results. All patients had C1 fractures type 3B according to Gehweiler, out of them 7 patients (46.7 %) had traumatic injury to the atlas transverse ligament according to Dickman type 1, and 8 patients (53.3 according to Dickman type 2. The average age of patients was 40 years (12; 71), the male/female ratio was 2/1. In 7 patients (46.7 %), the cause of injury was diving, in 6 (40.0 %) it was a traffic accident, and in 2 (13.3 %) – a fall from a standing height. Observation of patients revealed a positive dynamics in the form of statistically significant regression of pain according to VAS before and 6 months after surgery from 6.8 (6.0; 8.0) to 1.0 (1.0; 0.0) points (Z = -3.434; p = 0.001). A positive trend was also noted in the form of a decrease in NDI scores and an improvement in the quality of life after 3 (Z = -3.411; p = 0.001) and 6 months after surgery (Z = -3.410; p = 0.001). The range of motion (turn left/right, flexion/extension) increased statistically significantly by the 6th month after C1-ring osteosynthesis, and its indicators were close to physiological ones. Postoperative CT scans showed positive dynamics in the form of statistically significant regression of the lateral mass separation from 10.4 mm (8.9; 11.4) to 2.2 mm (1.8; 2.6); Z = -3.408; p = 0.001. Complete fusion of the atlas fracture was observed after 12.5 months (8.5; 16.5).Conclusion. Isolated posterior osteosynthesis of the atlas ring for Gehweiler type 3B injury using a repositioning compression maneuver under distraction conditions is physiologically justified. It is a reliable method of stabilization, ensures the restoration of congruence and the entire range of motion in the atlanto-occipital and atlantoaxial joints and stability of the occipital-atlantoaxial complex. This operation contributes to a considerable and long-term reduction in the intensity of pain syndrome and a significant improvement in the quality of life.

Impact of the Shape of the Skull Base on Morphometric Parameters of the First and Second Cervical Vertebrae in 8–12-Year-Old Children: Assessment of the Condition Under Norm and Recurrent Subluxation in the C1–C2 System

The aim of the study is to determine the impact of the shape of the skull base on the morphometric parameters of the first (C1) and second (C2) cervical vertebrae in children aged 8–12 under normal conditions and under recurrent subluxation of C1–C2. Materials and methods. The authors analysed computed tomography (CT) scans of 212 children aged 8–12 without pathology of the cervical spine and 65 patients of the same age group with recurrent subluxations of the C1-C2 vertebrae. Computed tomography was performed on a computer tomography GE OPTIMA CT 660, 64-slice machine (Russia). CT morphometry was carried out using the Radiant program (Russia). The width and length of the skull base, parameters of the first (C1) and second (C2) cervical vertebrae, and interosseous parameters were determined, the basilar index was calculated; three groups of individuals with dolicho-, meso-, or brachybasilar shape of the skull base were formed based on the value of the basilar index. One-way analysis of variance was carried out. Results The impact of the shape of the skull base of moderate strength on the transverse dimensions of the upper articular surfaces of C1 on the right and left in children without pathology of the cervical spine was revealed. Among the examined individuals with recurrent subluxation in the C1–C2 system, there was a strong connection between the shape of the skull base and the longitudinal dimensions of the upper articular surfaces of the atlas. A moderately close relationship was revealed between the shape of the skull base and the height of the body of the second cervical vertebra and with the angle of inclination of the C2 tooth in the sagittal plane in those examined without pathology of the cervical spine. In children with recurrent subluxation, a strong relationship of the controlled factor was determined with the height of the C2 body and the angle of inclination of its tooth in the sagittal plane, and a mediumstrong relationship with the sagittal diameter of the tooth. The influence of the shape of the skull base of moderate strength on the size of the anterior atlantoaxial joint space was revealed both in children without pathology of the cervical spine and in children with recurrent subluxation. In case of right-sided subluxation, a mediumstrong relationship between the shape of the skull base and the lateral distance between the base of the tooth and the medial surface of the lateral mass of C1 on the side contralateral to the subluxation was revealed. Conclusion. The shape of the skull base affects a number of anatomical structures of the first two cervical vertebrae in children aged 8–12.

Upper cervical epidural abscess with emphasis on diabetes as a risk factor: a case report

BackgroundAn upper cervical spine epidural abscess (UCEA) is an epidural abscess that develops in the area between the occiput and the second cervical spine (axis). It is a rare diagnosis that carries the risk of instability of the atlantoaxial joint, and its management is not well-defined. It is known that the skin is the most common source of infection, and that diabetes mellitus (DM) is the most frequently reported risk factor. In this case, we present a patient diagnosed with UCEA, who achieved full neurological recovery postoperatively despite having neurological deficits for over five days prior to surgery.Case presentationWe report the case of a 56-year-old male patient with no history of any prior medical conditions, who presented with headache, neck pain, and weakness of the left side. The weakness started approximately three days prior to his presentation. His initial work up revealed hyperglycemia and elevated HbA1c of 86 mmol/mol (10%). Magnetic resonance imaging (MRI) of the cervical spine revealed spondylitis of the C2 spine with an abscess at the craniocervical junction. He underwent a two-staged surgical approach: decompression and stabilisation. The patient achieved full motor recovery approximately three months postoperatively.ConclusionsWe recommend screening for DM when a spinal epidural abscess (SEA) is diagnosed without readily identifiable risk factors. The optimal management in most SEA cases is surgical, which is particularly true for UCEA because of the risk of atlantoaxial joint instability. Full neurological recovery is possible even when the patient has been having deficits for more than five days.

Minimally Invasive Surgery for Posterior Atlantoaxial Lateral Mass Joint Fusion (MIS-PALF): A Muscle-Sparing Procedure for Atlantoaxial Instability or Dislocation.

Conventional surgical procedures for atlantoaxial instability or dislocation (AAI/D) have been associated with a high prevalence of postoperative occipitocervical pain and dysfunction, as well as substantial perioperative blood loss. We hypothesized that minimally invasive surgery for posterior atlantoaxial lateral mass joint fusion (MIS-PALF), a procedure that can largely avoid disruption of suboccipital musculature, would be superior to the standard Goel-Harms technique in terms of postoperative pain and perioperative blood loss. This was a prospective cohort study of patients undergoing MIS-PALF for AAI/D at Peking University Third Hospital's Department of Orthopaedics from January 2021 to December 2021 and a historical control group of patients with the same diagnoses who were treated with the Goel-Harms technique. The duration of surgery, perioperative blood loss, postoperative length of hospital stay, postoperative body temperature, pain, supplementary use of narcotics, spinal cord function/improvement (assessed using the Japanese Orthopaedic Association [JOA] scores), reduction of AAI/D (determined based on radiographic parameters), rate of successful fusion, and complication rate were all compared between the 2 groups. No significant differences were noted between the groups (43 MIS-PALF cases, 86 control cases) regarding baseline data, operative time, spinal cord function or improvement, reduction of AAI/D, rate of successful fusion, and complication rate. MIS-PALF was associated with significantly less perioperative blood loss, a shorter postoperative hospital stay (decreased by 30.8%), lower intensity and frequency of postoperative pain (decreased by 10.6% and 61.9%, respectively), less need for supplementary narcotics, and less frequent postoperative fever (decreased by 48.7%). This was the first prospective cohort study of which we are aware on minimally invasive procedures for atlantoaxial fusion. Clinical efficacy (AAI/D reduction, rate of successful atlantoaxial fusion, JOA score improvement), efficiency (operative time), and safety (complications) of MIS-PALF appeared to be noninferior to those of the Goel-Harms technique. MIS-PALF was superior in terms of postoperative occipitocervical pain and length of hospital stay, both of which directly affect overall patient satisfaction and postoperative recovery of quality of life. Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Clinical history correlates with lateral atlantoaxial (C1-2) joint edema. A pilot study

BackgroundClinical evaluation in the determination of the etiology of axial spine pain is limited. ObjectiveTo determine if a set of three features of the clinical history are indicative of C1-2 joint edema on MRI. MethodsAll patients from one physician's practice who had axial cervical spine pain from 2021 to 2023 were evaluated. Cases were defined as those with all 3 of the ASL criteria, defined as Age >65, Superior cervical/suboccipital pain, and exacerbation of pain primarily by Lateral cervical spine rotation. Age-matched controls had axial cervical spine pain without meeting the ASL criteria. Edema around the atlantoaxial joint and/or odontoid was evaluated by STIR MR sequences. ResultsThe ASL criteria had a sensitivity of 82 % [95 % CI: 64–100 %], specificity of 79 %, [95 % CI: 63–95 %], positive predictive value of 74 % [95 % CI: 54–94 %], and negative predictive value of 86 % [95 % CI: 72–100 %] in diagnosing C1-2 joint edema. ConclusionA positive ASL criteria is sensitive and specific in the diagnosis of C1-2 joint edema, which may have clinical implications.

Posterior Release, Reduction, and Intra-Articular Fusion for Irreducible Type III Atlantoaxial Rotary Fixation.

For irreducible atlantoaxial rotary fixation (AARF), anterior or posterior release was often needed before posterior reduction and fusion. Anterior atlantoaxial joint release has potential complications such as retropharyngeal abscess, persistent hoarseness, and infection. This study aims to assess the efficacy of posterior release, reduction, and intra-articular fusion without resecting the C2 nerve root on irreducible type III AARF. The data of 9 pediatric patients diagnosed with AARF who underwent posterior atlantoaxial release, reduction, and intra-articular fusion without resecting the C2 nerve root were retrospectively reviewed. Japanese Orthopaedic Association scores and Visual Analog Scale for Neck Pain were used to assess outcomes. The preoperative and follow-up assessments of atlantodens interval (ADI) were documented to evaluate the reduction of atlantoaxial joint. The patient demographics, surgery time, blood loss, bone fusion time, follow-up period, and surgery-related complications were meticulously documented. The mean follow-up duration was 35.1 ± 11.5 months. Complete reduction was achieved in 8 patients, while one patient did not achieve complete reduction. The ADI decreased significantly from 8.7 ± 2.2 mm before surgery to 2.1 ± 1.3 mm at the final follow-up. All patients demonstrated successful bone fusion, with an average fusion period of 3.7 ± 1.3 months. The Visual Analog Scale for Neck Pain at the final follow-up exhibited a significant decrease compared with preoperative values (P < .05), while no significant difference was observed in Japanese Orthopaedic Association scores. There were no complications related to surgery. Posterior atlantoaxial release, reduction, and intra-articular fusion with a C2 nerve root preservation technique is effective in the treatment of irreducible type III AARF.

Analysis of Failed Atlantoaxial Reduction: Causes of Failure and Strategies for Revision.

The craniovertebral junction (CVJ) presents intricate anatomical challenges. In severe or irreducible malformations, complications such as reduction loss and fixation failure may occur, necessitating revision surgery. The posterior facet joint distraction and fusion (PFDF) technique, offers a solely posterior approach for revisions. Hence, we delineate varied revision scenarios, proposing surgical strategies and technical details to enhance outcomes and mitigate risks, thereby enriching the neurosurgical community's repertoire. This was a retrospective cohort study, analyzed patient data from Xuanwu Hospital, between 2017 to 2023. All patients had a history of surgical treatment for CVJ malformations, and experienced failure or loss of reduction. The distance from the odontoid process tip to the Chamberlain's line (DCL), the atlantodental interval (ADI), clivus-canal angle, cervicomedullary angle, width of subarachnoid space, CVJ area, and width of syrinx were used for radiographic assessment. Japanese Orthopaedic Association (JOA) scores and SF-12 scores were used for clinical assessment. Independent sample t-tests were employed. A significance level of p < 0.05 indicates statistically significant differences. We analyzed data from 35 patients. For patients who underwent PFDF, the postoperative DCL, ADI, and clivus-canal angle significantly improved. For all patients, the postoperative cervicomedullary angle, width of subarachnoid space, CVJ area, and width of syrinx all demonstrated significant improvement, indicating the relief of neural compression. All patients showed significant improvement in both symptoms and clinical assessments. Severe atlantoaxial joint locking or ligament contracting are the fundamental cause of reduction and fixation failure. Anterior odontoidectomy is indicated for patients with robust bony fusion of the atlantoaxial joint in an unreduced position. The PFDF technique is safe and effective for patients with incomplete atlantoaxial bony fusion. Preoperative assessment of surgical feasibility and vertebral artery status ensures surgical safety and efficacy.

How cervical and cervicothoracic scoliosis influence the atlantoaxial joint.

Children with cervical or cervicothoracic congenital scoliosis are limited in their ability to compensate for the main curve of the deformity because there are only a few mobile segments in their cervical spine. Over the years, we have frequently observed coronal atlantoaxial dislocation (CAAD) in a lateral direction (from left to right or vice versa) in these patients. It was anticipated that CAAD might compensate for the horizontal position of the head, and it is hypothesized that CAAD depends on the degree of scoliotic deformity. Thus, the aim of our study was to investigate whether there is a correlation between CAAD and scoliosis parameters in these patients. Retrospective analysis was performed based on CAT scans and preoperative X-rays of patients with cervical and cervicothoracic scoliosis with an apex between C4 and T6. Seventeen patients, with a mean age of 7.25 years, who were 9 girls and 8 boys, and who were treated between 2006 and 2022 were included. Cobb`s angle of the main curve (CA-MC), Cobb`s angle of the secondary curve (CA-SC), and T1-, C2- and UEV (upper end vertebra) tilt were measured on whole-spine radiographs in the standing position. The CAAD was measured via coronal CAT scan reconstruction and defined as the difference in the distances of the lateral masses to the midline of the axis. Pearson`s linear correlation coefficients (r) were determined using SPSS to evaluate correlations between CAAD and the measured parameters. p < 0.05 indicated statistical significance. CAAD toward the convex region in patients with scoliosis was typically observed; the mean CAAD was 3mm ± 3.7mm. The mean CA-MC was 46° ± 13°, the mean CA-SC was 16° ± 9.6°, the mean T1 tilt was 17° ± 8.8°, the mean C2 tilt was 9°± 8.8°, and the mean UEV tilt was 24° ± 7.2°. There was a strong linear correlation between CAAD and CA-MC (r = 0.784, p < 0.001), C2 tilt (r = 0.745; p < 0.001), and UEV tilt (r = 0.519; p = 0.033). There was no correlation between CAAD and either CA-SC or T1 tilt. Children with cervical or cervicothoracic scoliosis tend to have a CAAD toward the convexity of the scoliosis that correlates to CA-MC, C2-tilt, and UEV-tilt. CAAD may be seen as a compensatory mechanism to keep the head in a horizontal position. Severe or progressive CAAD may result in destruction of the atlantoaxial joint, including severe complaints, thus necessitating close follow-up and possibly early surgical treatment. Moreover, CAAD might be a useful additional radiographic parameter to be checked in future scoliosis studies.

Two-screw osteosynthesis is biomechanically superior to single-screw osteosynthesis for type II odontoid fractures

The data on the use of a one- or two-screw technique (1S, 2S) for ventral osteosynthesis of type II dens fractures are contradictory. The aim was to design an apparatus to mimic the physiological conditions and test stability with 1S, 2S, and a headless compression screw (HCS) for osteosynthesis of artificially created type II odontoid fractures. The apparatus was mounted on a Zwick materials testing machine. A total of 18 C1–2 specimens were stratified into three groups (1S, 2S, HCS). Odontoid fractures were artificially created, and osteosynthesis was performed. Each specimen was tested at loads increasing from 1 to 40 N. Screw loosening was observed visually, by fatigue data, and by a camera tracking system. Analysis of the Zwick data and the camera data revealed a significant higher stability after 2S compared to 1S and HCS treatment (Zwick data: p = 0.021, camera data: p < 0.001), while visible screw loosening showed a superiority of the 2S only over HCS (p = 0.038). The developed apparatus allowed the dynamic study of the atlantoaxial joint with a high approximation to physiological conditions. The results demonstrated superiority of the 2S over the 1S and HCS in biomechanical stability in the treatment of type II odontoid fractures.

Efficacy and Safety of Shi Cervical Rotational Manipulation in Patients With Atlantoaxial Joint Subluxation: Protocol for a Randomized Controlled Trial.

The clinical diagnosis of atlantoaxial joint subluxation (AJS) in traditional Chinese medicine (TCM) is characterized by an unequal distance between the lateral mass of the atlas and the odontoid process on imaging, resulting in neck pain accompanied by symptoms such as dizziness, headache, and limited cervical mobility. In Shanghai, Shi cervical rotational manipulation (SCRM) is a commonly employed TCM manual therapy for treating this condition. Nevertheless, there is a lack of evidence-based medical information regarding the clinical efficacy and safety of this technique. The principal aim of this study is to evaluate the efficacy and safety of SCRM in patients diagnosed with AJS. This study is a prospective randomized controlled clinical trial that will be conducted at a single center and that has a follow-up period of 24 weeks. A total of 96 patients diagnosed with AJS will be recruited from outpatient and inpatient clinics at Shanghai Baoshan Hospital of Integrated Traditional Chinese and Western Medicine. These patients will be randomly assigned to either the experimental group (SCRM) or the comparison group (basic cervical manipulation [BCM]). Treatment sessions consisting of SCRM or BCM will be administered twice a week for a duration of 4 weeks. Clinical monitoring indicators include the presence or absence of clinical symptoms as recorded on a symptom recording form, cervical imaging examination findings using cervical computed tomography, degree of neck pain measured by a visual analog scale (VAS), cervical range of motion assessed through cervical mobility measurement, degree of vertigo evaluated using the Vertigo Symptoms Scale-Chinese Version (VSS-C), and adverse events that may occur during the follow-up period. The time points for data collection and follow-up are baseline and postintervention (weeks 4, 8, 12, 16, 20, and 24). This paper presents an overview of the reasoning and structure of a prospective randomized controlled trial with the objective of investigating the clinical efficacy and safety of SCRM in patients with AJS by assessing improvements in clinical symptoms, neck pain severity, and vertigo severity and evaluating changes in cervical imaging findings. Recruitment was started in March 2023. By the end of May 2024, 76 patients were included in this project. The last follow-up data are predicted to be collected by the end of February 2025. This investigation will yield dependable evidence regarding the efficacy and safety of SCRM in patients with AJS. Chinese Clinical Trial Registry ChiCTR2300068510; https://www.chictr.org.cn/showprojEN.html?proj=186883. DERR1-10.2196/57865.

Cervical vertigo due to rotational fixation of atlantoaxial joint combined with benign paroxysmal positional vertigo: A case report and literature review.

Vertigo is the most common clinical complaint, misdiagnosed patients are not rare, so it is very important to exclude and identify vertigo. For vertigo caused by multiple causes, including cervical vertigo with atlantoaxial rotation fixation combined with benign paroxysmal positional vertigo (BPPV), tuina can correct joint misalignment. The reduction technique will return the fallen otolith to the correct position. The use of massage and reduction can improve clinical symptoms and improve quality of life and may be a simple, safe, and effective treatment strategy for this disease. We report on a patient with both cervical vertigo due to atlantoaxial rotational fixation and BPPV, including his imaging examination, clinical manifestations, and treatment methods. Cervical vertigo (atlantoaxial rotatory fixation) and BPPV. Tuina combined with atlantoaxial directional inverted reduction technique and reduction manipulation. The patient's vertigo symptoms improved significantly, nystagmus disappeared, cervical occipital pain, nausea, head distension, and other symptoms disappeared, and cervical motion rotation reached 60°. This study proved the effectiveness of massage combined with a reduction in the treatment of cervical vertigo and BPPV, as well as the importance of vertigo diagnosis and differential diagnosis, and provided a new treatment idea for the future diagnosis and treatment of vertigo caused by a variety of causes.

Sagittal slope angle of lateral atlantoaxial articulation is associated with the severity of basilar invagination with atlantoaxial dislocation and predicts reduction degree after surgery

ObjectiveTo investigate (1) lateral atlantoaxial articulation (LAA) morphology in patients with basilar invagination (BI) with atlantoaxial dislocation (AAD) and healthy individuals and its relationship with the severity of dislocation and (2) the effect of the LAA morphology on reduction degree (RD) after surgery.MethodsIn this retrospective propensity score matching case-control study, imaging and baseline data of 62 patients with BI and AAD from 2011 to 2022 were collected. Six hundred thirteen participants without occipitocervical junctional deformity served as controls. Logistic regression and receiver operating characteristic (ROC) curve were used for analysis.ResultsThe age, BMI and sex did not differ significantly between the two groups after propensity score matching. Sagittal slope angle (SSA) and coronal slope angle (CSA) was lower and greater, respectively, in the patient group than in the control group. A negative SSA value usually indicates anteverted LAA. Regression analysis revealed a significant negative correlation between SSA and severity of dislocation. However, no relationship was found between CSA and the severity of dislocation. The multivariate logistic regression analysis revealed that minimum-SSA emerged as an independent predictor of satisfactory reduction (RD ≥ 90%). The ROC curve demonstrated an area under the curve of 0.844, with a cut-off value set at -40.2.ConclusionSSA in patients group was significantly smaller and more asymmetric than that in the control group. Dislocation severity was related to SSA but not to CSA. Minimum-SSA can be used as a predictor of horizontal RD after surgery.

The Immediate Effect of Dry Needling Electric Muscle Stimulation on the Position of Atlas.

Background: cervicogenic headaches are common and are believed to be the cause of dysfunction in the upper cervical spine. The mobility and the position of the atlas have been identified as a cause of upper cervical dysfunction. The mobility of the atlas is entirely under the control of the suboccipital muscles. The oblique capitis inferior muscle has a rotatory effect on the atlas when contracted. This study evaluated the immediate effects of a dry needling electrical stimulation-induced contraction of the left oblique capitis inferior muscle on the position and mobility of the atlas in the atlantoaxial joint. Methods: thirty-one subjects participated in this within-subject repeated measure study design. Each subject underwent a pre-measures neck flexion rotation test, palpation of the atlas position, and measurement of the length of the right oblique capitis inferior muscle with musculoskeletal ultrasound imaging. The pre-measures were repeated after two five-second tetanic contractions of the oblique capitis inferior muscle. Results: post-intervention analysis revealed significant changes in the length of the right oblique capitis inferior muscle. This length change correlated with the palpated positional default position immediately after the intervention. Conclusions: two five-second tetanic contractions of the left oblique capitis inferior muscle immediately affected the position of the atlas in the atlantoaxial joint. In our subjects, 90% displayed a positional default in the left rotation, and this was correlated with a change in the neck flexion rotation test. This study supports the notion that suboccipital muscle tonicity can result in mobility dysfunction and, thus, conditions such as cervicogenic headaches.

Three Diverse, Nearly Misdiagnosed Inflammatory, and Infectious Diseases at Atlantoaxial Joint

Three Diverse, Nearly Misdiagnosed Inflammatory, and Infectious Diseases at Atlantoaxial Joint

Lateral atlanto-axial joint access using the C2 pedicle.

Neck pain and headaches can arise from the lateral atlanto-axial (LAA) joint. This pain can be diagnosed with intra-articular injections of local anesthetic. A widely used technique for access to the lateral atlanto-axial joint uses a posterior approach, but this approach can be hazardous because of the proximity of the vertebral artery, the dural sac, and the C2 spinal nerve and dorsal root ganglion. The objective was to describe and test a new technique for accessing the LAA joint that avoids structures that lie behind the joint. The new technique was described and tested for tolerance in 10 patients with unilateral suboccipital pain and tenderness over the LAA joint, along with evidence of LAA joint arthropathy on SPECT CT. The technique requires inserting a needle along a trajectory tangential to the dorsal surface of the C2 lamina. It involves obtaining a declined view of the C2 lamina and C2 pedicle. In all cases, the C2 pedicle was easily identified and allowed the needle to pass asymptomatically underneath the neurovascular structures behind the joint. The tactile response of the lamina of C2 provided important feedback regarding needle depth caudal to the LAA joint.

A quantitative study of mechanics in the treatment of atlantoaxial joint disorder by tendon relaxation manipulation

To explore dose-effect relationship of biomechanical parameters in treating atlantoaxial joint disorder by slimming manipulation. From October 2022 to May 2023, 18 patients with atlantoaxial joint disorders were treated, including 10 males and 8 females;aged from 24 to 27 years old with an average of (25.50±1.10) years old;CT of cervical vertebra showed 16 patients with right side distortion and 2 patients with left side distortion. The mechanical parameters of treatment of atlantoaxial joint disorder by tendon relaxation manipulation were measured by wearing massage manipulation gloves. The magnitude, frequency and mechanical curve of force during tendon relaxation and starting force, pulling force, pulling time and mechanical curve during rehabilitation were quantified, the differences between the affected and contralateral manipulations were compared. The maximum force and frequency of Fengchi(GB20) on the affected side were (19.82±2.02) N and (116.83±14.49) times/min, and opposite side were (13.87±2.19) N and (188.89±16.03) times/min, respectively. There were statistically difference in the maximum force and frequency of both sides (P<0.05). The maximum force and frequency of Quepen (ST12) on the affected side were (14.44±3.27) N and (139.06±28.47) times/min, and those on the opposite side were (9.41±1.38) N and (142.50±28.47) times/min. There was difference in maximum force on both sides (P<0.05). The starting force, turning force and turning time of the affected side were (14.16±5.98) N, (11.56±6.63) N, (0.14±0.03) S, and the contralateral side were (8.94±3.39) N, (8.30±4.64) N, (0.18±0.04) S, respectively. The difference of starting force, turning force and turning time on both sides were statistically significant (P<0.05). By applying a light relaxation force on the affected side, the mechanical balance between cervical vertebrae could be restored, and recovery trend of atlantoaxial joint disorder could be strengthened. On this basis, the atlantoaxial odontoid process could be reversed by applying a light rotation force, which reflects the characteristics of high safety of the manipulation.

An exclusionary screening method based on 3D morphometric features to sort commingled atlases and axes

In forensic commingled contexts, when the disarticulation occurs uniquely at the atlantoaxial joint, the correct match of atlas and axis may lead to the desirable assembly of the entire body. Notwithstanding the importance of this joint in such scenarios, no study has so far explored three-dimensional (3D) methodologies to match these two adjoining bones. In the present study, we investigated the potential of re-associating atlas and axis through 3D–3D superimposition by testing their articular surfaces congruency in terms of point-to-point distance (Root Mean Square, RMS). We analysed vertebrae either from the same individual (match) and from different individuals (mismatch). The RMS distance values were assessed for both groups (matches and mismatches) and a threshold value was determined to discriminate matches with a sensitivity of 100%. The atlas and the corresponding axis from 41 documented skeletons (18 males and 23 females), in addition to unpaired elements (the atlas or the axis) from 5 individuals, were superimposed, resulting in 41 matches and 1851 mismatches (joining and non-joining elements). No sex-related significant differences were found in matches and mismatches (p = 0.270 and p = 0.210, respectively), allowing to pool together the two sexes in each group. RMS values ranged between 0.41 to 0.77 mm for matches and between 0.37 and 2.18 mm for mismatches. Significant differences were found comparing the two groups (p < 0.001) and the highest RMS of matches (0.77 mm) was used as the discriminative value that provided a sensitivity of 100% and a specificity of 41%. In conclusion, the 3D–3D superimposition of the atlanto-axial articular facets cannot be considered as a re-association method per se, but rather as a screening one. However, further research on the validation of the 3D approach and on its application to other joints might provide clues to the complex topic of the reassociation of crucial adjoining bones.

Evaluation of the Bone Union Occurring Subsequent to C1-2 Fusion Combined With C1 Laminectomy for the Surgical Treatment of Retro-Odontoid Pseudotumor.

Introduction Surgical treatments for retro-odontoid pseudotumors (ROPs) include C1 laminectomies and C1-2 and occipitocervical (OC) fusions. When a C1 laminectomy is combined with a C1-2 fusion, concerns arise regarding an increased risk of pseudarthrosis due to decreased bone grafting space. Extension of the fusion area to the OC region may be considered to ensure an adequate bone graft bed. However, this procedure is associated with a risk of complications. Thus, in this study, we investigated the bone fusion and clinical outcomes of C1-2 fusion combined with a C1 laminectomy. Methods Between January 2017 and December 2022, seven patients with ROPs who had undergone C1-2 fusion combined with a C1 laminectomy were included in the study. All patients were followed up for >1 year. Bone fusion was evaluated by computed tomography (CT) at one year postoperatively, while implant failure was assessed by radiography at the final follow-up. Clinical evaluations included preoperative and one-year postoperative Japanese Orthopaedic Association (JOA) scores and recovery rates. Results This study included five male and two female patients, with an average age of 71.9 years. The average follow-up duration was 3.3 years. The primary anchor choices included the C1 lateral mass screw and the C2 pedicle screw. In one case, the transarticular screw was utilized unilaterally, and in another case, a lamina screw was utilized unilaterally. One year postoperatively, CT revealed bone fusion in three of the seven patients. Fusion occurred at the lateral and median atlantoaxial joints in two cases and one case, respectively. Screw loosening was observed in one case. None of the patients required reoperations. The average JOA recovery rate was 34.6%. Conclusion This surgical technique is useful for stabilizing and decompressing the C1-2 region while preserving mobility at the OC joint. However, further long-term follow-up studies are required.