Lateral atlanto-axial joint access using the C2 pedicle.

BACKGROUND: Neck pain and headaches can arise from the lateral atlanto-axial joint (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. OBJECTIVE: The objective was to describe and test a new technique for accessing the LAA joint that avoids structures that lie behind the joint. INTERVENTIONS: 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. CONCLUSIONS: 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.

Reference values of four measures of craniocervical stability using upright dynamic magnetic resonance imaging.

PURPOSE: To establish reference ranges for four most commonly used diagnostic measures of craniocervical instability (CCI) in three cervical sagittal positions. This necessitated development of a reliable measurement protocol using upright, dynamic MRI (udMRI), to determine differences in the extent of motion between positions, and whether age and sex correlate with these measures. MATERIALS AND METHODS: Deidentified udMRIs of 50 adults, referred for reasons other than CCI, were captured at three positions (maximal flexion, maximal extension and neutral). Images were analyzed, providing measures of basion-axial interval, basion-axial angle, basion-dens interval (BDI) and the Grabb-Oakes line (GOL) for all three positions (12 measures per participant). All measures were independently recorded by a radiologist and neurosurgeon to determine their reliability. Descriptive statistics, correlations, paired and independent t-tests were used. Mean (± 2 SD) identified the reference range for all four measures at each craniocervical position. RESULTS: The revised measurement protocol produced inter-rater reliability indices of 0.69-0.97 (moderate-excellent). Fifty adults' (50% male; mean age 41.2 years (± 9.7)) reference ranges for all twelve measures were reported. Except for the BDI and GOL when moving between neutral and full flexion, significant extents of movement were identified between the three craniocervical positions for all four measures (p ≤ 0.005). Only a minor effect of age was found. CONCLUSIONS: This is the first study to provide a rigorous standardized protocol for four diagnostic measures of CCI. Reference ranges are established at mid and ends of sagittal cervical range corresponding to where exacerbations of signs and symptoms are commonly reported.

Normal Range of Movement During Rotation Stress Testing for the Alar Ligaments: An Observational Study.

OBJECTIVE: The purpose of this study was to determine the normal range of rotation occurring during rotation stress testing for alar ligament integrity and to ascertain whether rotation range on testing is affected by an individual's age. METHOD: In this observational study, 88 people aged 18 to 86 years old with no current neck problems or known risk factors for craniocervical instability underwent rotation stress testing for the alar ligaments. The test was performed in each direction in neutral, flexion, and extension, with the participant both sitting and supine. Rotation range was recorded using an electromagnetic movement tracking system. Range was assessed overall and then compared by 10-year age groups using analysis of variance. Reliability of measurements was assessed by intraclass correlation coefficient(2,1) and standard error of measurement. RESULTS: Mean angles of upper cervical rotation ranged between 10.91° (standard deviation 3.38°) to 16.12° (standard deviation 5.13°). Overall measured rotation ranged from 1.37° to 33.22°. Participants in older age groups generally displayed reduced rotation; however, the reduction was less than 4°. Reliability of rotation measurements was good to excellent, with the intraclass correlation coefficient ranging from 0.80 to 0.99. CONCLUSIONS: Normal range of rotation measured during stress testing for the alar ligament varied widely but did not exceed 33o. All values measured in this study fell below recommendations for ligament integrity. Age-related change was not clinically significant in the interpretation of this test in this asymptomatic population.

Magnetic Resonance Imaging Investigation of Cervical-Spine Meniscoid Composition: A Validation Study.

OBJECTIVE: The composition of cervical-spine meniscoids may have clinical significance in neck-pain conditions, but the accuracy of assessment of meniscoid composition in vivo using magnetic resonance imaging has not been established. The aim of this study was to compare cervical-spine meniscoid composition by magnetic resonance imaging with histologic composition. METHODS: Four embalmed cadaveric cervical spines (mean [standard deviation] age, 79.5 [3.7] years; 1 female, 3 male) underwent magnetic resonance imaging, allowing radiologic classification of lateral atlantoaxial- and zygapophyseal-joint (C2-3 to C6-7) meniscoids as either mostly fatty, mixed tissue, or mostly connective tissue. Subsequently, each joint was dissected and disarticulated to allow excision of meniscoids for histologic processing. Each meniscoid was sectioned sagittally, stained with hematoxylin and eosin, examined using light microscopy, and classified as adipose, fibroadipose, or fibrous in composition. Data were analyzed using the kappa statistic with linear weighting. RESULTS: From dissection, 62 meniscoids were identified, excised, and processed; 46 of these 62 were visualized with magnetic resonance imaging. For single-rater identifying structures, agreement between assessment of meniscoid composition by magnetic resonance imaging and by microscopy was fair (κ = 0.24; 95% confidence interval, 0.02-0.46; P = .02). CONCLUSION: Findings suggest that the accuracy of this method of magnetic resonance imaging assessment of cervical-spine meniscoid composition may be limited. This should be considered when planning or interpreting research investigating meniscoid composition using magnetic resonance imaging.

Mobility of the upper cervical spine and muscle performance of the deep flexors in women with temporomandibular disorders.

BACKGROUND: Cervical spine disorders are frequently associated with temporomandibular disorders (TMDs). Although headache is common in TMD, few studies have considered headache regarding the functional performance of the cervical spine in TMD. OBJECTIVES: To evaluate TMD subjects with and without self-reported headache, assess the active and passive range of motion (ROM) of the upper cervical spine (C1-C2) and performance of the deep cervical flexors, and evaluate the correlation of these outcomes with neck disability and temporomandibular pain. METHODS: In this cross-sectional study, we assessed 57 women (40 with TMDs and 17 without TMDs [controls]). The TMD group was divided into 25 and 15 patients with and without self-reported headache, respectively. We assessed the active and passive upper cervical ROMs using the flexion-rotation test (FRT) and muscle performance using the craniocervical flexion test (CCFT). The neck disability index questionnaire and visual analog scale were used to assess self-reported neck disability and temporomandibular pain, respectively. RESULTS: Compared to controls, all TMD subjects showed reduced cervical mobility on flexion/extension movements, reduced FRT findings and worse performance in CCFT (P < .05 all). Additionally, the CCFT and FRT findings were correlated with temporomandibular pain (r = .4 and .5, respectively) and neck disability (r = .3 and .4, respectively). CONCLUSION: Women with TMDs, regardless of self-reported headaches, showed limited flexion/extension ROM, limited upper cervical spine (C1-C2) mobility and poor deep cervical flexor performance. Neck disability and temporomandibular pain showed a moderate correlation with the functional test findings, that is FRT and CCFT, in subjects with TMDs.

Reliability of Smartphone Inclinometry to Measure Upper Cervical Range of Motion.

CONTEXT: Assessment of upper cervical range of motion (UCROM) and mobility is commonly performed in the clinical setting for patients suffering from headache, neck pain, and vestibular dysfunction. Reliable and reproducible measurement of this motion is often difficult or too expensive to perform in the clinical setting. Smartphone applications using the device's internal gyroscope offer an easy and inexpensive means of measuring UCROM, but their reliability has not been reported in the literature. OBJECTIVE: To assess the reliability of an inclinometer application installed on 2 different devices (iPhone 6 [IP] and android [AN]) and to measure UCROM in a healthy population. DESIGN: Two examiners assessed passive UCROM. Each examiner was assigned to a specific smartphone, and a repeated-measures design consisting of 3 trials for each examiner-phone was performed. The order of testing was randomized, and the examiners were blinded to UCROM measures. SETTING: Laboratory. PARTICIPANTS: A total of 38 subjects (19 females and 19 males; age: 23.8 [1.2] y) without pain or injury to the neck or spine for at least 3 months. INTERVENTION: Each examiner passively flexed the head fully, rotated the head fully in 1 direction, and then in another. Peak rotation measures were recorded from each smartphone. Three trials were performed for each phone, with a 2-minute break between examiners/phones. MAIN OUTCOME MEASURES: Intraclass correlation coefficient using a 2-way mixed, absolute agreement model was obtained (1) between each examiner-phone and (2) within each examiner-phone for the measurements in each rotation direction. RESULTS: Interphone/examiner reliability comparing average peak and total UCROM for each device was excellent (.87, .81). Intraphone/examiner reliability, determined across 3 trials, was also excellent (AN right rot. = .91, AN left rot. = .96; IP right rot. = .98, IP left rot. = .95). CONCLUSION: UCROM can be reliably measured using a smartphone inclinometer application.

[Reduction of the atlantoaxial dislocation associated with basilar invagination through single-stage posterior approach: using Xuanwu occipital-cervical reduction surgical suite].

Objective: To examine the effect of posterior reduction in atlantoaxial dislocation (AAD) associated with basilar invagination(BI) using Xuanwu occipital-cervical fusion system in single stage. Methods: Thirty-seven AAD accompanied with BI cases treated at Department of Neurosurgery, Xuanwu Hospital, Capital Medical Universiy and the Second Hospital of Hebei Medical University were retrospective analyzed. There were 15 males and 22 females with age of (42.3±12.3)years (range: 18-69 yars). All the cases had congenital osseous abnormalities, such as assimilation of atlas and abnormal cervical fusion. Anterior tissue was released through posterior route followed by cage implantation into facet joint and occipital-cervical fixation with cantilever technique. The clinical results were evaluated using Japanese Orthopedic Association scale(JOA) and the main radiological measurements including anterior atlantodental interval (ADI),the distance of odontoid tip above Chamberlain line,clivus-canal angle (CCA) and the length of syrinx were collected.The preoperative and postoperative JOA score and radiological measurements were compared by paired t-test. Results: The mean JOA score of the patients increased from 10.5 to 14.4 at the one-year follow-up(t=14.3,P=0.00).Complete reduction of AAD and BI was achieved in 34 patients.The mean clivus-canal angle improved from 118.0 degrees preoperative to 143.7 degrees postoperative(t=6.2,P=0.00). Shrinkage of the syrinx was observed 1 week after surgery in 24 patients, and 6 months in 31 patients. Twenty-eight patients achieved bone fusion 6 months after surgery. All the patients achieved bone fusion 12 months after surgery. One-side vertebral artery occlusion was diagnosed in 1 case postoperatively for transient dizziness, and relieved in 2 weeks. Two patients developed moderate neck pain after surgery, and relieved in 1 month. No implant failure, spacer subsidence or infection was observed. Conclusions: The treatment of AAD associated with BI using Xuanwu occipital-cervical fusion system from posterior approach in single stage is effective and safe. Cage implantation intraarticularly and fixation with cantilever technique achieve complete reduction in most cases.

[Long-term follow-up of C(1)-C(2) pedicle screw fixation for pediatric atlantoaxial dislocation].

Objective: To investigate the clinical curative effect of C(1)-C(2) pedicle screw fixation for pediatric atlantoaxial dislocation after a long-term follow-up. Methods: From March 2005 to April 2011, a total of 12 male and 9 female patients were included, with age from 3 to 9 years old (mean, 6.1 years old). Among them, 14 cases (67%) had typeⅠinstability atlantoaxial dislocation, 7 cases (33%) had type Ⅱ reducible atlantoaxial dislocation. All 21 pediatric patients with atlantoaxial dislocation underwent posterior pedicle screw fixations. Frankel Grade was used to evaluate function before and after treatment. Furthermore, the information of C(1)-C(2) bony fusion, cervical spine alignment, angle of sagittal curvature, and instability of the subaxial spine were collected from all patients preoperatively, immediately postoperatively and during follow-up period. Results: All 21 patients had regular follow-up with an average duration of 96.4 months (range, 65 to 127 months). All children had good bony fusion within 6 months after treatment. There were 9 patients with lordotic alignment and 12 patients with straight alignment before surgery. After surgery, there were 12 patients with lordotic alignment and 9 patients with straight alignment. At the time of the last follow-up, 17 patients had lordotic alignment and 4 patients had straight alignment. No difference was found between pre- and post-operation (P=0.354). The same result was found between post-operation and last follow-up (P=0.095). Neither kyphotic nor swan-neck deformity was found in any of the 21 patients. The mean angle of sagittal curvature decreased from 31.7°±4.3°preoperatively to 15.5°±2.5°postoperatively (P<0.001). The mean angle of sagittal curvature increased from 15.5°±2.5°postoperatively to 19.1°±2.7°at the final follow-up (P=0.343). No spinal deformities or subaxial instabilities were found. Of the four patients with preoperative neurological defects, Frankel Grade was significantly improved at 3 months follow-up compared with pretreatment values. None of the patients experienced worsening neurological symptoms or injury to the vertebral artery. Conclusion: The results demonstrate that C(1)-C(2) pedicle screw fixation could achieve satisfactory clinical effects for the management of pediatric atlantoaxial dislocation with long-term follow-up.

[The rheumatic cervical spine]. / Die rheumatische Halswirbelsäule.

BACKGROUND: The cervical spine is one of the main sites of manifestation in rheumatoid arthritis outside of the extremities. It can have a decisive influence on disease course via the occurrence of mechanical instabilities as well as neurologic symptoms. Both adequate diagnosis and the corresponding surgical treatment represent a challenge for the involved physicians. MATERIALS AND METHODS: This review presents relevant diagnostic strategies and possibilities for surgical intervention which aim to avoid potentially fatal neurologic symptoms. Basic literature and expert opinions are also discussed. RESULTS AND CONCLUSION: Through target-oriented surgical management, as well as tight clinical and radiologic monitoring during conservative and surgical therapy, potentially fatal disease courses can be avoided.

[Treatment of single one-stage posterior atlantoaxial fixation in Chiari malformation].

Objective: To explore the effects of surgical technique of single one-stage posterior C(1-2) screw rod fixation of Chiari malformation (CM) associated with occipitalization and without atlantoaxial dislocation. Methods: A total of 23 patients with CM treated between January 2014 and October 2015 in Department of Neurosurgery of Chinese People's Liberation Army General Hospital were retrospective reviewed. All of them were diagnosis with CM associated with occipitalization and without atlantoaxial dislocation, including 8 males and 15 females, aging from 11 to 57 years (mean (35.5±10.52) years). Single one-stage posterior C(1-2) screw rod fixation with bone grafting fusion was performed. Operation time and intraoperative blood loss were recorded. Japanese Orthopaedic Association (JOA) scores and Odom rating were used to evaluate the clinical effects at pre- and post-operative. Regression of the cerebellar tonsillar was measured by MRI. The results were analyzed by paired samples t test. Results: Twenty-three patients were implanted screws successfully, the vertebral artery injury and cerebrospinal fluid leakage were not found. The mean operation time was (172.7±19.9) minutes, the intraoperative blood loss was (153.9±49.3) ml. Compared to preoperative, the JOA score increased (13.7±1.6 vs. 11.5±1.4) and the tonsillar herniation decreased ((0.8±0.6)cm vs. (1.9±0.6) cm) in the last follow-up, there were statistical difference (t=13.386, P<0.01; t=17.995, P<0.01). The results of the postoperative Odom grading were as follows: 6 cases were perfect (26.1%), 13 cases were good (56.5%), 4 cases were moderate (17.4%) and no case was poor.No signs of instrument loosen or screw broken was noticed. 100% bony fusion rate was achieved. The follow-up time was 6 to 23 months (mean (10.5±3.2) months). One case developed internal fixator related discomfort, the symptom was relieved by internal fixator removal surgery performed 4 months after the operation when osseous fusion had already been achieved. No new neurologic symptoms were observed in other 22 patients. Conclusions: The results of the study substantiates the effectiveness of single one-stage posterior fixation strategy for CM, which is associated with occipitalization and without atlantoaxial dislocation. This technique could be an alternative choice for this type of CM.

Neck-Tongue Syndrome.

Neck-tongue syndrome (NTS) is a headache disorder often initiated by rapid axial rotation of the neck resulting in unilateral neck and/or occipital pain and transient ipsilateral tongue sensory disturbance. In this review, we examine reported cases of NTS since its initial description in 1980 to highlight the significance of this condition in the differential diagnosis of headache in patients presenting with neck pain and altered tongue sensation. The anatomical basis of NTS centers on the C1-C2 facet joint, C2 ventral ramus, and inferior oblique muscle in the atlanto-axial space. NTS may be categorized as complicated (secondary to another disease process) or uncomplicated (hereditary, related to trauma, or idiopathic). Diagnosis is based on clinical suspicion after a thorough history and physical without a pathognomonic radiologic finding. It is typically treated conservatively with medications, local injections, immobilization with cervical collars, or physical therapy; rarely is surgical intervention pursued.

Biomechanical effects of the transcondylar approach on the craniovertebral junction.

The transcondylar variation of the far-lateral, retrosigmoid approach is intended for pathologies in the anterolateral portion of the foramen magnum. That area is more clearly visualized when a fraction of the ipsilateral occipital condyle is removed. In this study, the biomechanical effect of this approach on occiput-C2 rotation was investigated. Our hypothesis was that the biomechanical characteristics are significantly altered following the transcondylar approach. Five human cadaveric upper cervical spine specimens (occiput-C7) were used in the study. Torsional moments were applied from zero to a maximum of 1.5 N m to the left and to the right using a mechanical testing machine. The resulting rotational motions of the O-C1, C1-2, and O-C2 segments were measured in the intact specimen and after a simulated right-sided transcondylar approach with resection of 2/3 of the condyle, confirmed by CT scanning and visual inspection. After the posterior two-thirds of the occipital condyle were removed, the neutral zone (NZ) increased 1.3° to the left and 2° to the right at C0-C1, and 7.4° to the left and 6.2° to the right at C1-2. The cumulative increase in NZ between O and C2 was 8.7° to the left and 8.2° to the right. The transcondylar approach also resulted in significant increases in range of motion (ROM) in axial rotation to both sides in all segments. ROM increased 2.8° to the left and 2.4° to the right between C0 and C1, 7.3° to the left and 5.4° to the right between C1 and C2, and 10.1° to the left and 7.8° to the right between CO and C2. Upon inspection, the area of the occipital condyle where the alar ligament attaches had been completely removed in three of the five specimens. Removing the posteromedial two-thirds of one occipital condyle alters the normal axial rotational movements of the craniovertebral junction on both sides. The insertion of the alar ligament can be inadvertently removed during condylar resection, and this could contribute to atlanto-axial instability. There is a biomechanical substrate to cranio-cervical instability following a transcondylar approach; these patients may need to be followed over several years to ensure it does not progress and necessitate occipito-cervical fusion.

Intrafacet Spacer Placement as a Mobility-Sparing Bailout Option in Atlantoaxial Fusion Construct Salvage.

Background: Salvage revisions of atlantoaxial (AA) joint complex posterior segmental instrumented fusion constructs require careful individualized planning to prevent occipital extension. In this case report, we describe the use of bilateral intrafacet spacer placement as a mobility-sparing bailout option for the revision surgery. Case Report: A 64-year-old male with a history of diffuse idiopathic skeletal hyperostosis, extremely limited baseline cervical mobility, and prior AA posterior segmental instrumented fusion presented with increasing pain at his 6-month follow-up. Imaging showed fusion and hardware failures and dynamic instability. To prevent occipitocervical fixation, AA intra-articular fusion via a DTRAX spinal system (Providence Medical Technology, Inc) was used as an adjunct to a navigated C1 lateral mass and C2 pars screw posterior segmental instrumented fusion construct. The patient had an uneventful postoperative course and was discharged with resolution of symptoms. Three-month postoperative follow-up confirmed persistent resolution of symptoms and absence of complaints, along with successful arthrodesis on imaging. Conclusion: AA posterior segmental instrumented fusion revision is technically challenging, particularly when partial preservation of craniovertebral junction mobility is required. Bilateral intra-articular cages may be used as an adjunct to hardware revision in construct salvage when sturdy arthrodesis is desired without occipital extension and may represent a major potential strength of intra-articular cages.

Unexpected postoperative atlantoaxial rotatory subluxation after excision of melanocytic nevi of the head and neck in older children: two case reports and literature review.

Postoperative atlantoaxial rotatory subluxation (AARS) is a rare complication that develops almost exclusively in children following oropharyngeal and otologic surgeries, proposing that oropharyngeal inflammatory responses and excessive head rotation are responsible factors. However, there have been no reports of AARS after excision of a nevus on the head and neck. Here, we present two cases of AARS following limited head rotation during simple nevus excision. Patient 1, a 9-year-old girl, complained of neck pain and limited range of motion after excision of the nevus on the neck. After 2 months, computed tomography and magnetic resonance imaging finally revealed AARS with a ruptured transverse atlantal ligament. A month of halo traction was required for the treatment. Patient 2, an 11-year-old girl, presented with immediate pain and limited neck extension after tissue expander insertion under the upper chest and excision of the nevus on her left cheek. The diagnosis was promptly made using cervical spine radiography. A cervical collar was applied for 1 month. Both patients recovered without any complications after treatment. This report highlights the importance of suspicion for AARS after surgery regardless of surgical duration or amount of head rotation.

Clinical characteristics of upper cervical spine injuries in children: a retrospective case series.

OBJECTIVE: Pediatric cervical spine injuries (CSI) can be devastating, and children < 8 years are particularly at risk for upper CSI given unique anatomical differences. Diagnosis of these injuries can be delayed due to variable clinical presentations and a paucity of existing literature. The authors aimed to characterize the spectrum of pediatric upper CSI. METHODS: This was a retrospective, single-center case series of trauma patients aged < 16 years who were assessed at a level I pediatric trauma center and diagnosed with upper CSI between 2000 and 2020. Patients were included if they had evidence of bony or ligamentous injury from the occiput to C2 on imaging or autopsy. Data were obtained from manual chart review and analyzed using descriptive statistics. RESULTS: In total, 502 patients were screened and 202 met inclusion criteria. Of these, 31 (15%) had atlanto-occipital (AO) joint distractions, 10 (5%) had atlanto-axial (AA) joint distractions, 31 (15%) had fractures of C1-2, and 130 (64%) had ligamentous injury without joint distraction. Of the patients with AO injury, 15 patients had complete dislocation. They presented as hemodynamically unstable with signs of herniation and 14 died (93%). In contrast, 16 had incomplete dislocation (subluxation). They usually had stable presentations and survived with good outcomes. Of the patients with AA injury, 2 had complete dislocation, presented with arrest and signs of herniation, and died. In contrast, 8 patients with subluxation mostly presented as clinically stable and all survived with little residual disability. The most common fractures of C1 were linear fractures of the lateral masses and of the anterior and posterior arches. The most common fractures of C2 were synchondrosis, hangman, and odontoid fractures. Overall, these patients had excellent outcomes. Ligamentous injuries frequently accompanied other brain or spine injuries. When these injuries were isolated, patients recovered well. CONCLUSIONS: Among upper CSI, AO and AA joint injuries emerged as particularly severe with high mortality rates. Both could be divided into complete dislocations or incomplete subluxations, with clear clinical differences and the former presenting with much more severe injuries. Lateral cervical spine radiography should be considered during resuscitation of unstable trauma patients to assess for these CSI subtypes. Fractures and ligamentous injuries were clinically heterogeneous, with presentations and outcomes depending on severity and associated injuries.

Posterior-only approach for treatment of irreducible traumatic Atlanto-axial dislocation, secondary to type-II odontoid fracture; report of a missed case, its management and review of literature.

INTRODUCTION AND IMPORTANCE: Odontoid fracture (OF) is among the most common and challenging cervical spine fractures in regards to the treatment and surgical approach. Atlanto-axial dislocation (AAD) is considered a significant complication after failed non-surgical treatment of OF. Traditionally, it requires anterior odontoidectomy followed by posterior C1-C2 reduction and fusion. In latest studies, Atlanto-axial joint (AAJ) remodeling in a posterior-only approach has got attention. CASE PRESENTATION: We herein present a 30-year-old man with missed type-II OF, presenting with irreducible anterior AAD and progressive neurological deficit. Old non-united OF with dorsal callous formation, compressing spinal cord, was detected. The patient underwent correction of the deformity and reduction of the fracture utilizing the posterior-only approach. AAJ remodeling, callous release and C1-C2 fusion was performed in standard prone position, under fluoroscopic guide and intraoperative electrophysiological monitoring. The patient had uneventful surgery and postoperative course and was neurologically intact with appropriate alignment in 6-month follow-up. CLINICAL DISCUSSION: The irreducible AAD following type-II OF could be successfully treated with posterior-only approach (C1-C2 fusion). CONCLUSION: Type-II OF is considered unstable requiring surgical management. Close follow-up and appropriate patient education is mandatory in non-surgical treatment. Irreducible AAD has been managed with anterior odontoid resection and posterior fusion. Several complications of anterior surgery, makes posterior-only approach a noticeable choice.

Improvement in JOA Score of Treatment for Complex Atlas-Axis fractures.

OBJECTIVE: The aim of this study was to explore the role of treatment for complex Atlas-Axis fractures, and compare the JOA score of surgical and conservation methods. METHODOLOGY: From June 2008 to May 2012, 33 patients suffering from Atlas-Axis fracture were included in our study. Fifteen patients received posterior cervical pedicle screw fixation, and 18 patients received the conservation treatment. All the patients were followed up for 12 months after discharge. RESULTS: The mean operative time was about 128 minutes (ranged: 92 to 165 minutes), the mean hospital stay time was 15.5 days (ranged: 8-21 days), and the mean follow-up of all the patients was 27months (ranged: 7 to 43 months). All patients gained a solid fusion, and no one showed any disability at the end of the follow-up. The JOA scores before treatment were 6.4±0.3 and 7.1±0.4 before and after treatment, and they significantly increased to 13.8±0.8 and 13.7±0.9 when following up for 12 months (P<0.05). CONCLUSIONS: Posterior cervical pedicle screw fixation is a feasible, effective and safe method for complex atlantoaxial fractures. This technique could achieve high JOA score, decreased blood loss and post-operative complications.

Traumatic C2-C3 subluxation with atlanto-axial dislocation managed by posterior approach - A rare case report.

INTRODUCTION AND IMPORTANCE: Traumatic subluxation of C2-C3 with Atlanto-Axial dislocation is very rare and uncommon condition. Only a very few case reported. What constitutes appropriate management in cases of traumatic C2-C3 subluxation with Atlato-axial dislocation is still controversial due to the infrequency of this injury. We managed a patient who had traumatic C2-C3 subluxation with Atlanto-axial dislocation following a history of trauma through posterior approach successfully. CASE DESCRIPTION: A 45-year male day laborer presented with neck pain with progressive neurological deficit after two episodes of fall with heavy object within 1 year. Imaging revealed complete dislocation of C2 over C3 with Atlanto-Axial Dislocation. The patient was approached for posterior fixation with attempt to reduction per-operatively with skeletal traction and C1, C2, C3 joint distraction. After distraction of the joint, we achieved to do reduction of the C2-C3 and Atlanto-Axial joint. We did C1 lateral mass, C2 pedical and C3, C4 lateral mass screw and put a spacer in between C1-C2 facet joint. The patient was improved immediately after the operation. One year follow up shows, he was completely well. One year follow up shows in radiography proper alignment with fusion between C1, C2 and C3. CLINICAL DISCUSSION: Traumatic subluxation of the C2 vertebra is due to fractures of the lamina, articular facets, pedicles, or pars interarticularis and was first described by Bouvier in1843. To the best of our knowledge there has been 3/4 cases reported till now with traumatic C2-C3 subluxation with AAD. In three similar cases before ours, one was reported to be reduced after 3 weeks of bidirectional cervical traction and another two cases were managed by open reduction and stabilization. We managed this rare case surgically successfully through posterior approach with good outcome. CONCLUSION: Our management through posterior approach between C1 to C4 shows very good outcome with proper fusion. But it needs proper understanding the anatomy and mechanism of reduction by careful reading the image. Its needs more case description and management to establish a standard treatment for this type of disease.

Dual-Energy Computed Tomography Collagen Density Mapping of the Cranio-Cervical Ligaments-A Retrospective Feasibility Study.

The objectives of this study were to investigate the mean collagen content of the atlanto-axial joint (AAJ) ligaments in a cohort without inflammatory disease and to analyze clinical confounders such as age, sex, and presence of ligamentous calcifications. A total of 153 patients who underwent dual-energy computed tomography (DECT) due to various reasons (e.g., suspected cancer or infection) were included in this retrospective study. Reconstruction of collagen density maps from the DECT dataset was performed. Region of interest (ROI) analysis was performed to assess densities in the following regions: ligamentum transversum atlantis (LTA), ligamenta alaria, fasciculi longitudinales, ligamentum nuchae, and retro-odontoid soft tissue (RDS). Osteoarthritis (OA) and the presence of calcifications were assessed by two experienced readers blinded to clinical data. Subgroup comparisons were performed using unpaired t-tests. The correlation of collagen density and clinical factors was investigated using Pearson's correlation coefficient. Mean LTA collagen density was 141.7 (SD 35.7). Ligamentous calcifications were rare (14.4 %). OA of the AAJ was common (91.5 %). LTA collagen density was not associated with age (Pearson's r of 0.109; p = 0.180) and was not significantly higher in patients with OA (p = 0.070). No correlations between RDS thickness, collagen density or calcifications were found. Our results show collagen density mapping of the cranio-cervical joint ligaments to be feasible; collagen densities are not significantly associated with age, sex, AAJ degeneration, or asymptomatic ligamentous calcification.

[Correlative analysis of cervical curvature and atlantoaxial instability].

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