Atlantoaxial Facet Joint Research Articles

Odontoid Fracture with Accompanying Severe Atlantoaxial Instability in Elderly Patients-Analysis of Treatment, Adverse Events, and Outcome.

(1) Background: In elderly patients with type II odontoid fractures, accompanying severe atlantoaxial instability (AAI) is discussed as a marker possibly warranting more aggressive surgical therapy. This study aimed to characterize adverse events as well as the radiological and functional outcomes of surgical vs. conservative therapy in patients with odontoid fracture and AAI. (2) Methods: Patients aged 65 years and older with type II odontoid fracture and AAI treated were included. AAI was assumed if the mean subluxation across both atlantoaxial facet joints in the sagittal plane was greater than 50%. Data on demographics, comorbidities, treatment, adverse events, radiological, and functional outcomes were analyzed. (3) Results: Thirty-nine patients were included. Hospitalization time was significantly shorter in conservatively treated patients compared to patients with ventral or dorsal surgery. Adverse events occurred in 11 patients (28.2%), affecting 10 surgically treated patients (35.7%), and 1 conservatively treated patient (9.1%). Moreover, 25 patients were followed-up (64.1%). One secondary dislocation occurred in the conservative group (11.1%) and three in the surgical group (18.8%). (4) Conclusions: Despite the potential for instability in this injury, conservative treatment does not seem to lead to unfavorable short-term results, less adverse events, and a shorter hospital stay and should thus be considered and discussed with patients as a treatment option, even in the presence of severe AAI.

Direct intraoperative two-step distraction and reduction for basilar invagination with atlantoaxial dislocation

Objective: To assess the clinical impact of direct two-step distraction reduction (TSDR) for basilar invagination (BI) with atlantoaxial dislocation (AAD). Methods: Retrospective analysis was conducted on the clinical data of patients who underwent TSDR and occipitocervical fusion in West China Hospital between October 2013 and March 2021. Depending on whether the preoperative decrease was greater than 50% on preoperative hyperextension X-rays, the patients were split into two groups. The neurological function [Japanese Orthopedic Association (JOA) score], atlantodens interval (ADI), the distance of odontoid process beyond McRae Line (ML) and Wackenheim Line (WL), cervicomedullary angle (CMA), O-C2 angle (OC2A), and complications incidence were compared between two groups preoperatively and postoperatively. Results: There were 12 men and 23 women among the 35 patients with BI and AAD, and the age ranged from 28 to 71 years, with an mean age of (52.0±13.4) years. In the preoperative reduction ≥50% group, there were 4 males and 9 females with an average age of (54.0±13.8) years; in the preoperative reduction <50% group, there were 8 males and 14 females with a mean age of (50.9±13.4) years. All the patients were followed-up for a mean time of (23.3±13.4) months. There was no significant difference in age, gender, bleeding, length of hospital stay and follow-up time between the two groups (all P>0.05). The JOA score, ADI, WL, ML and CMA of 35 patients were significantly improved when compared with those before operation (all P<0.05). The reduction degree of ADI, ML and WL was more than 80% in 31 cases (88.57%), 30 cases (85.71%) and 31 cases (88.57%), respectively. There was no significant difference in postoperative ADI, ML and WL between the two groups (all P>0.05). All patients had no incision infection, no loosening or breakage of the internal fixators. Dysphagia occurred in 3 patients, non-fusion happened in 1 patient, but no instability in X-ray of cervical dynamic position was found, no loosening or displacement occurred in internal fixators, and partial spontaneous fusion occurred between atlantoaxial lateral mass joints. Conclusions: For BI with AAD without atlantoaxial bony connection or serious atlantoaxial facet joint inclination, TSDR could obtain satisfactory reduction degree. The reduction degree on preoperative hyperextension X-ray doesn't affect the degree of intraoperative reduction.

Surgical management of Grisel syndrome in the adult patient: illustrative case.

BACKGROUNDGrisel syndrome describes an infectious soft tissue process that destabilizes the cervical bony elements and ligamentous complexes. This nontraumatic atlantoaxial rotary subluxation occurs in children primarily. This case illustrates a rare case presentation of an adult with Grisel syndrome: infectious destruction of the right atlantoaxial facet joint caused the occiput-C1 vertebra (head) to rotate rightward with lateral horizontal displacement off the C2 vertebra.OBSERVATIONSBecause the infection destroyed the C1 bony arch and atlantoaxial facet joints with epidural extension, the rotated head and atlas pulled the brainstem–cervical spinal cord junction against a fixed odontoid process, resulting in a cord contusion. Because of the highly unstable craniocervical junction, the patient presented with torticollis and left upper extremity weakness.LESSONSTreatment entailed closed reduction under general anesthesia followed by occipitocervical fusion with an occipital plate, C1 lateral mass screws, and C2-C5 pedicle screws. This case describes the unique surgical pearls necessary for occipitocervical fusion of an unstable craniocervical junction, including tips with neuronavigation, trajectories of the cervical pedicle screws, aligning the lateral mass and pedicle screws with the occipital plate, and nuances with occipitocervical distraction.

Intraarticular bone grafting in atlantoaxial facet joints via a posterior approach: nonstructural or structural\u2014a minimum 24-month follow-up

ObjectiveTo investigate the necessity of nonstructural or structural intraarticular bone grafting in atlantoaxial facet joints via a posterior approach and the influence by the presence of basilar invagination (BI).MethodsFrom November 2016 to October 2018, patients who underwent posterior atlantoaxial or occipitocervical arthrodesis surgery at one institute were retrospectively reviewed. Operation records, preoperative and postoperative clinical status, and radiological films were analyzed.ResultsThirty-three patients (19 without BI, 14 with BI) underwent posterior facet joint release followed by intraarticular bone grafting were enrolled finally. Twenty-four nonstructural (15 without BI, 9 with BI) and 9 structural (4 without BI, 5 with BI) grafting were performed. The average follow-up was 32.15±6.73 months (24–47 months). Among them, 1 (3.03%) implant failure occurred, and 32 (96.97%) achieved satisfactory neurological outcomes, including 28 (84.85%) complete and 4 (12.12%) acceptable reductions with complete fusion within 6 months. For patients without BI, structural and nonstructural grafting showed no significant difference in terms of reduction maintenance (100% vs 73.33%, p = 0.530), while for those with BI, structural grafting significantly increased the postoperative height of the joint space (5.67±1.22 mm vs 3.43±1.78 mm, p = 0.002) and maintained it much better than nonstructural grafting (88.89% vs 20.00%, p = 0.023), contributing notably to BI correction.ConclusionIntraarticular structural bone grafting in atlantoaxial facet joints has the advantage of maintaining anterior column height in the case of lateral mass collapse or when BI correction is needed; otherwise, nonstructural bone grafting is enough.

Upper cervical spine tuberculosis

Tuberculosis is an infection caused by Mycobacterium tuberculosis; mainly affects the lungs; spinal tuberculosis presents 6 % of the extrapulmonary locations; Upper cervical spine tuberculosis is a rare condition and counts only 0.3 to 1 % of all spinal tuberculosis; that makes it a rare condition studied by few case reports. We report a case of upper cervical spine tuberculosis of the atlantoaxial facet joint.

Correlation between osteoarthritis of the atlantoaxial facet joint and a high\u2010riding vertebral artery

BackgroundA high-riding vertebral artery (HRVA) is an intraosseous anomaly that narrows the trajectory for C2 pedicle screws. The prevalence of a HRVA is high in patients who need surgery at the craniovertebral junction, but reports about HRVAs in subaxial cervical spine disorders are limited. We sought to determine the prevalence of HRVAs among patients with subaxial cervical spine disorders to elucidate the potential risk for VA injury in subaxial cervical spine surgery.MethodsWe included 215 patients, 94 were with a main lesion from C3 to C7 (subaxial group) and 121 were with a main lesion from T1 to L5 (thoracolumbar group). A HRVA was defined as a maximum C2 pedicle diameter of < 3.5 mm on axial CT. The sex, age of patients, body mass index (BMI), osteoarthritis of the atlantoaxial (C1-2) facet joints, and prevalence of a HRVA in the 2 groups were compared and logistic regression was used to identify the factors correlated with a HRVA.ResultsThe patients in the subaxial group were younger than those in the thoracolumbar group, but their sex and BMI did not differ significantly between the 2 groups. The mean osteoarthritis grade of the C1-2 facet joints of patients in the subaxial group was significantly higher than that in those in the thoracolumbar group. A HRVA was found in 26 patients of 94 (27.7 %) in the subaxial group and in 19 of 121 (15.7 %) in the thoracolumbar group. The prevalence of a HRVA in the subaxial group was significantly higher and osteoarthritis of C1-2 facet joints correlated significantly with a HRVA.ConclusionsThe prevalence of a HRVA in patients with subaxial cervical spine disorders is higher than in those without and osteoarthritis of the C1-2 facet joints is correlated with a HRVA.

Analysis of three-dimensional facet joint displacement during two passive upper cervical mobilizations

BackgroundUnderstanding the 3D-kinematics of the upper cervical spine during manual mobilization is essential for clinical examination and therapy. Some information about rotational motion is available in literature but translational components are often ignored, complicating the understanding of the complex inter-segmental motions. ObjectivesThis study aims to describe the amount, trajectories and reproducibility of atlanto-occipital facet joints’ displacement during a flexion-extension mobilization and of the atlanto-axial facet joints during an axial rotation mobilization. DesignOriginal research using quantitative data. Methods20 fresh frozen human cervical specimens were examined with a Zebris® CMS20 ultrasound-based motion tracking system. Two physiotherapists performed regionalmobilizations in flexion-extension and axial rotation. The amount of displacement and the trajectories were calculated along the XYZ axes. Difference between measurements was evaluated with the Friedman two-way ANOVA test. Intra- and inter-rater reliability were estimated through ICC scores. Results3D-displacement (2.6–23.4 mm) was larger at C1–C2 during axial rotation, Atlanto-occipital flexion displayed the greatest variability in the C0 trajectory. During a right rotation, the left C1 facet moved mainly forward, and the right C1 facet moved backward. During a left rotation, the left C1 facet moved backward, while the right C1 facet moved forward. Intra-tester and Inter-tester ICCs varied between 0.5 and 0.90 (p < 0.005). ConclusionsDuring passive spinal motion, there is an important variability in magnitude and trajectory of joints’ displacement. Nevertheless, different clinicians may be able to achieve the same position at the end of the mobilization.

New Classification and Its Value Evaluation for Atlantoaxial Dislocation.

ObjectiveTo introduce the TOI classification system (the Traction reduction type [T type], Operation reduction type [O type], and Irreducible type [I type] classification system) and to determine the interobserver and intraobserver reliability of the TOI classification system.MethodsBased on the characteristics of atlantoaxial dislocation (AAD), AAD was divided into Traction reduction type (T type), Operation reduction type (O type), and Irreducible type (I type). The analysis of interobserver and intraobserver agreements was done using kappa statistics. From July 2016 to January 2019, 213 AAD patients were retrospectively studied at four hospitals. Plain radiographs including extension and flexion views and three‐dimensional CT images were obtained. Twenty independent observers, including eight experienced spine specialists and 12 orthopaedic fellows from four different residency training hospitals, completed the survey.ResultsThe classification of the TOI system was based on etiology, the course of the disease, flexion–extension X‐rays, three‐dimensional CT reconstruction, and curative effects of skull traction. Flexion–extension X‐rays demonstrating a successful reduction of the dislocated atlantoaxial joint and three‐dimensional CT images showing osseous fusion of atlantoaxial facet joints and cervical traction reveal characteristics of T‐type. Furthermore, this type can be divided into two subtypes, T1 and T2, according to the etiology and course of the disease. Unsatisfactorily reduction after 1–2 weeks of strict cervical traction, no reduction shown on flexion–extension X‐rays, and no destruction or boneless fusion of atlantoaxial facet joints demonstrated in three‐dimensional CT images are characteristics of type O. Atlantoaxial facet joint showing bone fusion or failure of reduction after cervical traction or three‐dimensional CT images showing failure of surgical release are characteristics of type I. Interobserver and intraobserver reliability of the TOI classification system were moderate (κ = 0.543) and substantial (κ = 0.658), respectively. Interobserver and intraobserver reliability of the treatment choice were moderate (κ = 0.568) and substantial (κ = 0.675), respectively. There were no significant differences in the interobserver and intraobserver reliability between experienced spine specialists and fellows for all κ‐values (P > 0.05).ConclusionsThe TOI classification system had satisfactory reliability and, therefore, can be applied clinically and used by less experienced surgeons. We believe TOI can help surgeons choose appropriate treatment strategies.

Posterior intra-articular distraction with cage placement to treat congenital atlantoaxial dislocation associated with basilar invagination.

Congenital atlantoaxial dislocation (AAD) associated with basilar invagination (BI) is a complex congenital malalignment at the craniovertebral junction. The olisthesis, atlantoaxial facet joint arthropathy, and the contraction of the anterior soft tissue make the treatment challenging. Our video demonstrates the surgical technique for posterior intra-articular distraction with cage placement to treat congenital atlantoaxial dislocation associated with basilar invagination.The video can be found here: https://youtu.be/7EQqW96HhN8

Posterior atlantoaxial facet joint reduction, fixation and fusion as revision surgery for failed suboccipital decompression in patients with basilar invagination and atlantoaxial dislocation: Operative nuances, challenges and outcomes

ObjectiveTo report the technical nuances and clinical outcomes of posterior atlantoaxial facet joint reduction, fixation and fusion (AFRF) technique as a revision procedure for BI and AAD patients with failed suboccipital decompression and large occipital bone defect. Patients and methodsWe reviewed 32 patients with BI and AAD who were misdiagnosed as a simple Chiari malformation and received a suboccipital decompression surgery before admission. All patients underwent AFRF as a revision surgery. The separating, fusing, opacifying and false-coloring-volume rendering (SFOF-VR) technique was used to identify the course of the VA. Clinical and radiological outcomes were assessed after revision surgeries. ResultsClinical symptoms improved in all patients. The postoperative atlantodens interval, Wackenheim line and clivus-canal angle significantly improved (all P < 0.01). Intraoperative dural tear and cerebrospinal fluid leakage occurred in 3 patients and were managed by suture repair and lumbar drain. Abnormal VA was identified in 7 patients and no VA injury occurred with the aid of SFOF-VR technique. The average follow-up was 19.1 months and atlantoaxial bone fusion was confirmed in 31 patients. ConclusionFor BI and AAD patients with failed suboccipital decompression, revision surgery is challenging. Occipitocervical fixation and posterior midline bone grafting are rather difficult due to the large occipital bone defect. The current study demonstrated that the posterior AFRF is a simple, safe and highly effective technique in revision surgery for such cases. For VA variations, the SFOF-VR technique is an effective tool to delineate the course VA.

Usefulness of 3D Printed Models in the Management of Complex Craniovertebral Junction Anomalies: Choice of Treatment Strategy, Design of Screw Trajectory, and Protection of Vertebral Artery

To evaluate the usefulness of 3-dimensional (3D) printed models as an aid for the treatment of complex CVJ anomalies. 3D printed models were fabricated for 21 patients with complex CVJ anomalies, including vertebral artery anomaly, thin C2 pedicle, vertical atlantoaxial facet joint, or rotational dislocation combined with atlantoaxial dislocation and basilar invagination. Preoperative planning, surgical simulation, and intraoperative reference were achieved using the 3D model during the surgical treatment. The usefulness of 3D printed models, and postoperative clinical and radiological outcomes were assessed. Direct posterior reduction and atlantoaxial fixation were achieved in 19 patients. Transoral odontoidectomy followed by posterior fixation was implemented for 2 patients with vertical facet joint and rotational dislocation. All screws were safely inserted with no complication, and 90% patients achieved a >60% reduction of both horizontal and vertical dislocation. Clinical symptoms improved in all patients, with the averaged Japanese Orthopedic Association scores increasing from 11.14 to 14.43 (P < 0.01). The patient-specific 3D printed model would be an effective tool for evaluation of the reducibility of the atlantoaxial dislocation and basilar invagination, decision making in choosing the optimal surgical approach and way of fixation, and precise placement of the screw while protecting the vertebral artery and spinal cord. The risk of neurovascular injury was minimized, and encouraging outcomes were achieved with the aid of this technique.

Traumatic Chronic Irreducible Atlantoaxial Rotatory Fixation in Adults: Review of the Literature, With Two New Examples.

Atlantoaxial rotatory fixation (AARF) is a rare condition in adults and is almost always due to an accompanying trauma. The first example of traumatic AARF in adults was reported by Corner in 1907 and since then only 55 adult cases with this rare traumatic scenario have been published so far. Approximately 80% of adults with traumatic AARF are diagnosed soon after the traumatic events. However, in the remaining casualties, the condition might be missed with some delay from the diagnosis to treatment. If this pathology is diagnosed early enough, the conservative attempts for a closed reduction are usually effective. After closed reduction, external immobilization is required to prevent recurrence of the dislocation. However, with delayed diagnosis, the condition may remain refractory to traction on manipulation and require an open reduction instead. In the literature, such irreducible chronic AARFs are rarely reported, being confined to only 14 adult examples, in whom surgical intervention for correction of the deformity will be required. In such cases, release of the atlantoaxial facet joints is the first surgical step. In the subsequent step, reduction of the dislocated facet joints can be done via one of the already described maneuvers. As the final step, C1-C2 fixation will be necessary for prevention of re-dislocation. Herein, 2 adult patients with chronic rotatory atlantoaxial dislocation of traumatic origin are presented. In both cases, cranial traction and manipulations were ineffective and therefore an open reduction procedure was proposed and accomplished via the posterior midline corridor. The transverse rod technique was implemented subsequent to the atlantoaxial facet release. After correction of the deformity, a C1-C2 fixation was accomplished followed by arthrodesis. In addition to the outlined procedure, an historical review of the literature on this subject from the beginning of 20th century is demonstrated.

Role of Posterior Interfacetal Distraction and Grafting in Complex Atlanto-Axial Dislocation

Background data: Atlanto-axial fixation, unlike subaxial spine, is still challenging due to complex topographical anatomy. Nowadays, atlas lateral mass screws and transpedicular axis screws fixation is a well-accepted technique for the management of atlantaoaxial instability due to their rigid fixation and higher fusion rate. However, in complex cases like basilar invagination, further reduction and proper bony alignment is needed. Study design: a retrospective descriptive clinical case series. Objective: The aim of this work was to assess the safety and efficiency of bilateral posterior atlanto-axial facet joint distraction and insertion of spacer in reducing complex cases of atlantoaxial instability. Patients and methods: Out of 17 patients with atlanto-axial instability, five patients underwent posterior fixation and atlanto-axial facet joint distraction and insertion of spacer for reduction of irreducible atlantoaxial dislocation. Clinical results were evaluated by using the criteria of Japanese Orthopaedic Association Scoring System for Cervical Myelopathy (JOA score). The surgical technique, results and morbidity and mortality were assessed. Results: There were 3 females and 2 males; the age ranged from 10y-50y). The cause of significant instability was trauma (2 patients), while each of the 3 other patients suffered from Down syndrome, rheumatoid arthritis and post tuberculous infection. All 5 patients had pyramidal tract compression manifestations. At the end of follow up (mean 18m), the average preoperative JOA score improved from 13.2 ± 1 SD to 15.9 ± 0.2 SD (p = 0.04) and the average recovery rate was 69% ± 12 % SD. Postoperative CT scans showed the mean atlantodens interval improved from 6.2mm ± 1.6 to 1.8mm ± 0.8 (p = 0.04), the mean clivus-canal angle increased from 119.8° ± 3.7° to 135.2° ± 7°(p = 0.04). The average extra time and blood loss of bilateral facet distraction and grafting was about 65m (p value = 0.004) and 72.5 ml respectively. There was no mortality, vertebral artery injury, CSF leak or construct failure. Conclusions: Bilateral posterior atlanto-axial facet joint distraction and placement of spacer is a safe and effective adjunct procedure for reduction of complex atlanto-axial instability.

Torticollis and rotatory atlantoaxial dislocation: A clinical review.

Rotatory atlantoaxial instability can manifest as an acute episode following subtle or minor injury or even following a gentle tap on head in young children and can manifest as a painless deformity of the head. Goel technique of direct surgical opening of the atlantoaxial facet joint, manual manipulation of the facets can lead to reduction of rotatory atlantoaxial dislocation and recovery from torticollis. Torticollis can be a protective natural phenomenon in response to atlantoaxial instability and related basilar invagination. Only atlantoaxial fixation can lead to immediate postoperative reduction of torticollis. Spasmodic torticollis related to muscle hyperactivity is unrelated to atlantoaxial instability.

Applied anatomy study of C2 nerve root and its surrounding venous plexus

Objective To study the anatomical structure of cervical 2 nerve root and its surrounding venous plexus at the lateral joint of atlantoaxial joint, and to explore the optimal operation mode of atlantoaxial dislocation and fixation with cervical screws. Methods Six adult head and neck specimens were perfused. The bilateral C2 nerve roots and their surrounding venous plexuses were dissected and observed under microscope. Measurement and analysis of related anatomical structures were performed. Results Atlantoaxial lateral posterior joint was rich in venous plexus. The medial part of the venous plexus covered the normal dura mater and had a clear membrane boundary. The C2 nerve root coursed inside the venous plexus from the medial superior side towards lateral inferior direction. The total width of the plexus was 21.1±2.1 mm. The distance from the medial border of the venous plexus to the posterior median line was 5.7±1.3 mm. After sufficient dissection of plexus from the dura mater, the distance was increased to 14.1±1.0 mm. The distance from the middle line of C2 pedicle to the lateral and median side of venous plexus was 10.7±2.1 mm and 5.9±1.2 mm, respectively. The upper and lower distances between C2 nerve root and lateral margin of plexus were 6.3±1.3 mm and 2.6±0.6 mm, respectively. Atlantoaxial lateral facet joint was exposed after cleaning of venous plexus and dissection of C2 nerve root. The height and width of exposed C1 lateral joint were 6.6±0.3 mm and 13.7±0.5 mm, respectively. The height of exposed superior articular process of C2 was 4.9±0.3 mm, and the width of C2 pedicle was 8.2±0.3 mm. Conclusions It is of significance in instructing surgical operations to clearly understand the anatomy of C2 nerve root and its surrounding venous plexus. During implantation of C1 lateral mass screw and C2 pedicle screw, the incision along the middle line of C2 pedicle to dissect the C2 nerve root could provide maximal exposure and help reduce venous bleeding. Key words: C2 nervous root; Venous plexus; C1/2 lateral facet; Anatomy

Distraction Arthrodesis of the Atlantoaxial Facet Joint with Preservation of the C2 Root for the Management of Intractable Occipital Neuralgia Caused by C2 Root Compression

Introduction Vertical collapse of the C1-C2 facet joint may cause narrowing of the C2 root foramen with root compression, resulting in severe occipital neuralgia. The purpose of this study was to evaluate the prospectively collected outcomes data of a distraction arthrodesis surgical group (Study group) in comparison to a Control group in a non-randomized design. Material and Methods The Study group underwent intraoperative skeletal traction, preservation of the C2 nerve roots, facet joint distraction and insertion of a bone block and cancellous bone into the joint along with posterior fusion, and segmental screw fixation using posterior C1 arch screws instead of lateral mass screws. The Control group had C2 root transection with C1-C2 segmental screw fixation and arthrodesis. Inclusion criteria for both groups were (1) occipital neuralgia caused by C2 root compression confirmed by clinical manifestation and imaging studies including radiographs, CT scan, and MRI, (2) intractable pain (VAS≥7) unresponsive to nonoperative treatment, and (3) follow-up period ≥12 months. We compared the preoperative and postoperative 10-point VAS scores for occipital neuralgia and neck pain; NDI; and JOA scores and recovery rates. Results There were 15 patients in the Study group and 8 in the Control group. All had facet joint destruction and/or collapse caused by underlying disorders including rheumatoid arthritis (Study group: 5 ; Control group: 3), rheumatoid arthritis with odontoid nonunion (2, 0), odontoid nonunion (3, 1), unifacet spondylosis (3, 2), os odontoideum (2, 1), and cerebral palsy (0, 1). There was no significant difference in age (61 ± 6, 62 ± 9), gender (4 and 3 men, respectively), and the number of cases with accompanying myelopathy (5, 2) between the 2 groups. The follow-up period averaged 21 ± 12 versus 33 ± 25 months, respectively. There was no significant difference in the VAS score for the preoperative occipital neuralgia (8.2 ± 0.9, 7.9 ± 0.6, p = 0.39). However, it was significantly lower in the Study group at 1, 3, 6, and 12 months postoperatively (p = &lt;0.01, respectively). At 12 months, the VAS was 0.4 ± 0.6 versus 2.5 ± 2.6 ( p = 0.01). In the Study group, all patients had little or no pain (VAS ≤2) while 2 patients (25%) in the Control group were still on medication (Gabapentin) with moderate to severe pain (VAS 4 and 8 respectively). There was no significant difference in preoperative and postoperative VAS scores for neck pain, NDI, and JOA scores and recovery rate, since these values are minimally influenced by occipital neuralgia. Conclusion Our results suggest that our novel technique of distraction arthrodesis can be an effective option for the management of intractable occipital neuralgia caused by C2 root compression. Prospective randomized studies are required for better evaluation.

Posterior Reduction of Fixed Atlantoaxial Dislocation and Basilar Invagination by Atlantoaxial Facet Joint Release and Fixation: A Modified Technique With 174 Cases.

Treatment of fixed atlantoaxial dislocation (AAD) with basilar invagination (BI) is challenging. To introduce a modified technique to reduce fixed AAD and BI through a posterior approach. From 2007 to 2013, 174 patients with fixed AAD and BI underwent surgical reduction by posterior atlantoaxial facet joint release and fixation technique. There was 1 death in the series, and 3 patients were lost to follow-up. The follow-up period ranged from 12 to 52 months (mean: 35.2 months) for the remaining 170 patients. Neurological improvement was observed in 168 of 170 patients (98.8%), and was stable in 1 (0.06%) and exacerbated in 1 (0.06%), with the Japanese Orthopedic Association scores increasing from 11.4 preoperatively to 15.8 postoperatively (P < .01). Radiologically, complete or >90% reduction was attained in 107 patients (62.9%), 60% to 90% reduction was attained in 51 patients (30%), and <50% reduction was attained in 12 patients (7.1%), who underwent additional transoral decompression. Complete decompression was demonstrated in all 170 patients. Solid bony fusion was demonstrated in 167 patients at follow-up (98.2%). This series showed the safety and efficacy of the posterior C1-2 facet joint release and reduction technique for the treatment of AAD and BI. Most fixed AAD and BI cases are reducible via this method. In most cases, this method avoids transoral odontoidectomy and cervical traction. Compared with the occiput-C2 screw method, this short-segment C1-2 technique exerts less antireduction shearing force, guarantees longer bone purchase, and provides more immediate stabilization.

Craniovertebral Junction Instability: A Review of Facts about Facets.

Craniovertebral junction surgery involves an appropriate philosophical, biomechanical and anatomical understanding apart from high degree of technical skill and ability of controlling venous and arterial bleeding. The author presents his 30-year experience with treating complex craniovertebral junction instability related surgical issues. The facets of atlas and axis form the primary site of movements at the craniovertebral junction. All craniovertebral junction instability is essentially localized to the atlantoaxial facet joint. Direct manipulation and fixation of the facets forms the basis of treatment for instability.

Prevalence of degenerative changes of the atlanto-axial joints

Background contextDegeneration of the atlantodens and atlanto-axial joints is associated with cervical spine pain and may also be associated with an increased risk of dens fracture. However, there is paucity of literature describing the prevalence of specific degenerative changes in the atlantodens and atlanto-axial facet joints. PurposeTo document age-related degenerative changes of the cervical spine in a large cohort of patients. Study design/settingThis is a retrospective cohort study. Patient sampleAdult trauma patients were admitted to our Level 1 trauma center. Outcome measuresOsteoarthritis of the atlantodens and atlanto-axial facet joints of the cervical spine and the presence of intraosseous cyst and calcific synovitis, as determined by computed tomography (CT) scans. MethodsWe conducted a retrospective study of 1,543 adult trauma patients who received a cervical spine CT scan. The anterior atlantodens joint interval was measured. The presence or absence of intraosseous cysts and calcific synovitis was recorded. Degeneration of the atlantodens and atlanto-axial facet joints at age intervals was quantified. ResultsThe atlantodens interval narrowed linearly with age (R2=0.992, p<.001). The prevalence of intraosseous cysts increased exponentially with age from 4.2% to 37.4%, and calcific synovitis increased from 0% to 11.1%. Intraosseous cyst formation generally began in the second and third decades of life and synovitis in the fifth and sixth decades of life. Facet joints also demonstrated age-related changes; however, the rate of degenerative changes was lower than in the atlantodens joint. ConclusionsTo our knowledge, this is the first study that documents specific changes of both atlantodens and atlanto-axial facet joints as a function of age in a large cohort of 1,543 patients. These changes increased exponentially with age and may contribute to pain and limitation in motion. In light of our findings and recent studies demonstrating the association between degeneration and dens fracture in elderly, cervical spine radiographs of elderly patients should be carefully assessed for these changes.

A fourth atlantoaxial joint: an initial description

Background contextThe presence of a supernumerary posterior atlantoaxial facet joint has not been reported in the literature. PurposeTo describe a patient who presented with a unilateral anomalous posterior facet joint and discuss its possible embryological origin. Study design/settingCase report. MethodsA 35-year-old woman presented with severe neck pain, headaches, and tingling radiating down her left arm. Radiological studies showed an anomalous right C1–C2 facet joint causing dorsal compression of the spinal cord and cord compression secondary to a C5–C6 herniated disc. The patient underwent resection of the abnormal facet via a posterior approach followed by anterior cervical discectomy and fusion at C5–C6. ResultsThe patient reported marked improvement in her neck pain and partial improvement in her left upper extremity numbness and tingling. Postoperative radiographs showed no abnormal motion at C1–C2. ConclusionsThe authors hypothesize that, in this patient, the C1 and C2 sclerotomes may have fused abnormally posteriorly, followed by the initiation of events at this site that eventually led to the formation of a morphologically normal synovial joint in an abnormal location.