Atlantoaxial Subluxation in Different Intraoperative Head Positions in Patients with Rheumatoid Arthritis

Background: Disorders of the cervical spine are often observed in patients with rheumatoid arthritis (RA). However, the best head position for RA patients with atlantoaxial subluxation in the perioperative period is unknown. This study investigated head position during general anesthesia for the patients with RA and proven atlantoaxial subluxation.

Methods: During anesthesia of patients with RA and proven atlantoaxial subluxation, the authors used fluoroscopy to obtain a lateral view of the upper cervical spine in four different positions: the mask position, the intubation position, the flat pillow position, and the protrusion position. Copies of the still fluoroscopic images were used to determine the anterior atlantodental interval, the posterior atlantodental interval, and the angle of atlas and axis (C1-C2 angle).

Results: The anterior atlantodental interval was significantly smaller in the protrusion position (2.3 mm) than in the flat pillow position (5.1 mm) (P < 0.05). The posterior atlantodental interval was significantly greater in the protrusion position (18.9 mm) than in the flat pillow position (16.2 mm) (P < 0.05). The C1-C2 angle was, on average, 9.3[degrees] greater in the protrusion position than in the flat pillow position (P < 0.05).     

Rheumatoid arthritis in the cervical spine

The cervical spine often becomes involved early in the course of rheumatoid arthritis, leading to three different patterns of instability: atlantoaxial subluxation, atlantoaxial impaction, and subaxial subluxation. Although radiographic changes are common, the prevalence of neurologic injury is relatively low. The primary goal of treatment is to prevent permanent neurologic injury while avoiding potentially dangerous and unnecessary surgery. Strategies include patient education, lifestyle modification, regular radiographic follow-up, and early surgical intervention, when indicated. Magnetic resonance imaging is indicated when neurologic deficit (myelopathy) occurs or when plain radiographs show atlantoaxial subluxation with a posterior atlantodental interval < or =14 mm, any degree of atlantoaxial impaction, or subaxial stenosis with a canal diameter < or =14 mm. Surgery should be considered promptly for any of the following: progressive neurologic deficit, chronic neck pain in the setting of radiographic instability that does not respond to nonnarcotic pain medication, any degree of atlantoaxial impaction or cord stenosis, a posterior atlantodental interval < or =14 mm, atlantoaxial impaction represented by odontoid migration > or =5 mm rostral to McGregor's line, sagittal canal diameter <14 mm, or a cervicomedullary angle <135 degrees.     

Predictors of paralysis in the rheumatoid cervical spine in patients undergoing total joint arthroplasty

BACKGROUND: Rheumatoid arthritis is sometimes associated with radiographic evidence of instability of the cervical spine, most commonly an abnormal subluxation between vertebrae. When this instability compromises the space that is available for the spinal cord, it may be predictive of paralysis. However, the prevalence of radiographic signs of instability that are predictive of paralysis among patients with nonspinal orthopaedic manifestations of rheumatoid arthritis is unknown. METHODS: Radiographs of the cervical spine of patients with rheumatoid arthritis who had undergone total joint arthroplasty over a five-year period were retrospectively reviewed. The radiographs were evaluated for predictors of paralysis (a posterior atlantodental interval of <14 mm or a subaxial space available for the cord measuring <14 mm) and were compared with traditional parameters of instability (an anterior atlantodental interval of >3 mm or subaxial subluxation of >3 mm). RESULTS: Forty-nine of the sixty-five patients who were identified had flexion and extension lateral radiographs available for review. Only one of these patients had a posterior atlantodental interval of <14 mm, and only three had a space available for the cord that measured <14 mm at one level or more. In comparison, twenty patients had radiographic evidence of instability on the basis of traditional parameters. CONCLUSIONS: Although nearly one-half of the patients in the present study had radiographic evidence of cervical instability on the basis of traditional measurements, only four patients (8%) had a radiographic finding that was predictive of paralysis. Thus, while radiographic evidence of cervical instability was not infrequent in this population of patients who underwent total joint arthroplasty for rheumatoid arthritis, radiographic predictors of paralysis were much less common.     

Subaxial subluxation after atlantoaxial transarticular screw fixation in rheumatoid patients

The most common cervical abnormality associated with rheumatoid arthritis (RA) is atlantoaxial subluxation, and atlantoaxial transarticular screw fixation has proved to be one of the most reliable, stable fixation techniques for treating atlantoaxial subluxation. Following C1–C2 fixation, however, subaxial subluxation reportedly can bring about neurological deterioration and require secondary operative interventions. Rheumatoid patients appear to have a higher risk, but there has been no systematic comparison between rheumatoid and non-rheumatoid patients. Contributing radiological factors to the subluxation have also not been evaluated. The objective of this study was to evaluate subaxial subluxation after atlantoaxial transarticular screw fixation in patients with and without RA and to find contributing factors. Forty-three patients who submitted to atlantoaxial transarticular screw fixation without any concomitant operation were followed up for more than 1 year. Subaxial subluxation and related radiological factors were evaluated by functional X-ray measurements. Statistical analyses showed that aggravations of subluxation of 2.5 mm or greater were more likely to occur in RA patients than in non-RA patients over an average of 4.2 years of follow-up, and postoperative subluxation occurred in the anterior direction in the upper cervical spine. X-ray evaluations revealed that such patients had a significantly smaller postoperative C2–C7 angle, and that the postoperative AA angle correlated negatively with this. Furthermore, anterior subluxation aggravation was significantly correlated with the perioperative atlantoaxial and C2–C7 angle changes, and these two changes were strongly correlated to each other. In conclusion, after atlantoaxial transarticular screw fixation, rheumatoid patients have a greater risk of developing subaxial subluxations. The increase of the atlantoaxial angel at the operation can lead to a decrease in the C2–C7 angle, followed by anterior subluxation of the upper cervical spine and possibly neurological deterioration.     

Biomechanical rationale for the pathology of rheumatoid arthritis in the craniovertebral junction

STUDY DESIGN: A finite-element model of the craniovertebral junction was developed and used to determine whether a biomechanical mechanism, in addition to inflammatory synovitis, is involved in the progression of rheumatoid arthritis in this region of the spine. OBJECTIVES: To determine specific structure involvement during the progression of rheumatoid arthritis and to evaluate these structures in terms of their effect on clinically observed erosive changes associated with the disease by assessing changes in loading patterns and degree of anterior atlantoaxial subluxation. SUMMARY OF BACKGROUND DATA: Rheumatoid arthritis involvement of the occipito-atlantoaxial (C0-C1-C2) complex is commonly seen. However, the biomechanical contribution to the development and progression of the disease is neither well understood nor quantified. Although previous cadaver studies have elucidated information on kinematic motion and fusion techniques, the modeling of progressive disease states is not easily accomplished using these methods. The finite-element method is well suited for studying progressive disease states caused by the gradual changes in material properties that can be modeled. METHODS: A ligamentous, nonlinear, sliding-contact, three-dimensional finite-element model of the C0-C1-C2 complex was generated from 0.5 mm thick serial computed tomography scans. Validation of the model was accomplished by comparing baseline kinematic predictions with experimental data. Transverse, alar, and capsular ligament stiffness were reduced sequentially by 50%, 75%, and 100% (removal) of their intact values. All models were subjected to flexion moments replicating the clinical diagnosis of rheumatoid arthritis using full flexion lateral plane radiographs. Stress profiles at the transverse ligament-odontoid process junction were monitored. Changes in loading profiles through the C0-C1 and C1-C2 lateral articulations and their associated capsular ligaments were calculated. Anterior and posterior atlantodental interval values were calculated to correlate ligamentous destruction with advancement of atlantoaxial subluxation. RESULTS: Model predictions (at 0.3 Nm) fell within one standard deviation of experimental means, and range of motion data agreed with published in vitro and in vivo values. The model predicted that stresses at the posterior base of the odontoid process were greatly reduced with transverse ligament compromise beyond 75%. Decreases through the lateral C0-C1 and C1-C2 articulations were compensated by their capsular ligaments. Anterior and posterior atlantodental interval values indicate that the transverse ligament stiffness decreases beyond 75% had the greatest effect on atlantoaxial subluxation during the early stages of the disease (no alar and capsular ligament damage). Subsequent involvement of the alar and capsular ligaments produced advanced atlantoaxial subluxation, for which surgical intervention may be warranted. CONCLUSIONS: To the best of the authors' knowledge, this is the first report of a validated, three-dimensional model of the C0-C1-C2 complex with application to rheumatoid arthritis. The data indicate that there may be a mechanical component (in addition to enzymatic degradation) associated with the osseous resorption observed during rheumatoid arthritis. Specifically, erosion of the odontoid base may involve Wolff's law of unloading considerations. Changes through the lateral aspects of the atlas suggest that this same mechanism may be partially responsible for the erosive changes seen during progressive rheumatoid arthritis. Anterior and posterior atlantodental interval values indicate that complete destruction of the transverse ligament coupled with alar and/or capsular ligament compromise is requisite if advanced levels of atlantoaxial subluxation are present.     

寰枢关节类风湿性关节炎的影像学分析(附21例报告)

目的评估累及寰枢关节的21例RA患者经联合治疗的临床效果及其影像学特征。方法对平均病程为7．95年（2～26年）的21例患者行MTX＋其他DMARDs的联合治疗,同时行临床和影像学评估,明确16例存在寰枢椎前向半脱位、3例垂直半脱位、2例侧方半脱位。6例有明显枕颈部症状的寰枢不稳息者行后路寰枢或枕颈融合治疗。结果联合治疗的有效率为85．7％。RA病程越长,越易发生寰枢椎不稳和椎管矢状径减小,本组前向寰枢椎半脱位最常见。6例手术患者的齿突周围血管翳在随访中较术前明显减小。结论对累及寰枢关节的RA患者,无论有无寰枢椎不稳、有无症状或脊髓损伤的体征,均可成功行影像学评估且行MTX＋其他DMARDs的联合治疗可取得较好的疗效;为防止枕颈部脊髓压迫,宜对此类患者行常规、定期的临床和影像学评估。     

Effect of biological agents on cervical spine lesions in rheumatoid arthritis

STUDY DESIGN.: A retrospective cohort analysis. OBJECTIVE.: To determine the effect of biological agents (BAs) on the development and progression of cervical spine lesions and identify predictors of lesion progression. SUMMARY OF BACKGROUND DATA.: The introduction of BAs has facilitated advances in the treatment of rheumatoid arthritis (RA). BAs reduce disease activity and limit structural joint damage. However, the effect of BAs on cervical spine lesions remains unclear. METHODS.: Thirty-eight subjects who received more than 2 years of continuous BA treatment were enrolled. The mean x-ray interval was 4.4 years. RA activity was evaluated by disease activity score (DAS)-C reactive protein (CRP) and matrix metalloproteinase (MMP)-3. Radiographical definitions of cervical lesions were atlanto-dental interval (ADI) more than 3 mm for atlanto-axial subluxation (AAS), Ranawat value less than 13 mm for vertical subluxation (VS), and anterior or posterior listhesis more than 2 mm for subaxial subluxation (SS). Definitions of radiographical progression were an increase of ADI more than 2 mm for AAS, a decrease of both Ranawat and Redlund-Johnell values more than 2 mm for VS, and an increase of listhesis more than 2 mm for SS. RESULTS.: RA activity responded dramatically to BA therapy (DAS-CRP from 4.3 to 2.3, P < 0.01; MMP-3 from 207.9 ng/mL to 105.6 ng/mL, P < 0.01). Baseline radiographical evaluation showed no pre-existing cervical spine lesions in 12 cases, AAS in 15 cases, and VS in 11 cases. Radiological progression was found in 1 (8%) patient in the no lesion group, 12 patients (80%) in the AAS group, and 9 patients (80%) in the VS group. The incidence of progression was significantly lower in the no lesion group compared with the other groups. Multivariate regression analysis showed that the presence of pre-existing cervical lesions was the single greatest predictor of progression. CONCLUSION.: BAs prevented the development of de novo cervical spine lesions in patients with RA, but failed to inhibit progression of pre-existing RA lesions.     

类风湿性关节炎继发寰枢椎脱位的手术治疗

目的:总结手术治疗类风湿性关节炎(rheumatoid arthritis,RA)继发寰枢椎脱位的临床疗效。方法:2010年1月~2018年12月收治57例RA继发寰枢椎脱位的患者,男14例,女43例;年龄46~79岁(61.8±12.4岁)。类风湿性关节炎病史2.5~36.8年(17.5±3.7年),诊断RA后出现上颈椎相关症状时间为1.5~19.4年(8.9±2.4年)。患者均有不同程度的枕颈部疼痛、颈部姿势异常和活动受限。术前神经功能ASIA分级:B级3例,C级12例,D级20例,E级22例;JOA评分4~14分(8.7±1.8分),VAS 4~10分(7.4±1.5分)。寰椎前向脱位44例,其中寰齿前间距(anterior atlantodental interval,AADI)>10mm者8例;寰椎后向脱位9例;寰椎前后向脱位4例。6例合并下颈椎不稳,10例合并枕颈部其他畸形。13例枕寰关节先天性融合及骨性融合无枕寰关节活动度者采用枕颈固定融合术治疗(A组);44例有枕寰关节活动度的患者采用寰枢椎融合固定融合术治疗,其中16例寰枢椎脱位牵引不能复位的患者先行前路经下颌下寰枢椎关节松解术再一期后路行寰枢椎融合术治疗(B组),28例寰枢椎脱位牵引能复位的患者直接采用后路寰枢椎融合内固定术治疗(C组)。定期随访患者的临床症状和神经功能改善情况,影像学观察寰枢椎复位和植骨融合情况。结果:患者均顺利完成手术,A组手术时间100~130min(118.2±13.5min),术中出血量100~300ml(190.5±42.8ml);B组手术时间180~240min(221.4±20.3min),术中出血量100~260ml(157.3±36.1ml);C组手术时间100~130min(109.4±12.1min),术中出血量100~200ml(124.1±32.7ml)。术中均未发生椎动脉和脊髓损伤。所有患者随访期间复查颈椎CT及MRI显示寰枢椎序列重建满意,齿状突区域脑脊液线清晰,脊髓无压迫,术后AADI为2~3mm(2.4±0.4mm)。患者均获随访,随访时间12~84个月(34.4±10.3个月),术后12个月随访时,2例ASIA分级B级患者恢复至C级,C级患者6例恢复至D级、3例恢复至E级,9例D级患者恢复至E级,其余患者无变化;JOA评分改善至10~17分(14.6±3.5分),VAS评分降至1~5分(3.6±1.4分),与术前比较均有显著性差异(P<0.05)。1例患者植骨块发生自发性部分吸收,随访1年半时植骨块吸收停止并部分融合,未再次行植骨术;其余患者植骨均融合。随访期间均未发现螺钉松动、移位、断裂和寰枢椎再脱位、失稳现象。结论:RA累及上颈椎时会造成寰枢椎脱位导致脊髓受压,依据枕寰关节活动度情况采用寰枢椎融合术或枕颈融合术治疗可获得良好的临床效果。     

Atlantoaxial subluxation associated with ossification of posterior longitudinal ligament of the cervical spine

STUDY DESIGN: Two case reports. OBJECTIVE: To demonstrate two rare cases of atlantoaxial subluxation associated with ossification of the posterior longitudinal ligament of the cervical spine, in which spastic quadriplegia developed. SUMMARY OF BACKGROUND DATA: There are only two reports of an association of diffuse idiopathic skeletal hyperostosis with atlantoaxial subluxation. This condition often accompanies ossification of the posterior longitudinal ligament of the cervical spine, but there is nothing in the literature about the association of ossification of the posterior longitudinal ligament with atlantoaxial subluxation. METHODS: Clinical and radiographic findings of these two cases were demonstrated. In both cases laminoplasty of the cervical spine was performed with occipitoaxial arthrodesis. RESULTS: The spastic quadriplegia of these two patients caused by myelocompression improved after surgical intervention. CONCLUSION: Ossification of the posterior longitudinal ligament of the cervical spine may cause atlantoaxial subluxation.     

Timing of cervical spine stabilisation and outcome in patients with rheumatoid arthritis

One complication of rheumatoid arthritis (RA) is the involvement of the cervical spine (CS). Although prophylactic stabilisation is recommended, the timing at which this should occur is poorly defined. The aim of our study was to evaluate the course of neurological symptoms in terms of the timing of surgery. A total of 34 patients with RA and CS involvement were surgically stabilised. These patients were classified using the Ranawat (RW) score both preoperatively and at an average of 54 months post-operatively. For each patient, the presence of atlantoaxial and subaxial subluxation as well as vertical migration of the odontoid was recorded. The anterior atlantodental interval was also assessed pre- and post-operatively. Improvement was obtained in 20 patients, the clinical situation remained unchanged in three patients and three patients manifested disease progression. In terms of the RW score, the 16 patients with pre-operative RW grades I-II showed no deterioration at the post-operative follow-up, with 13 of these patients showing an improvement; the 12 patients with pre-operative RW grades IIIA-IIIB did not show any improvement of neurological symptoms at follow-up, although seven of these patients subjectively assessed the symptoms to be less severe after surgery; three other patients showed a worsening of symptoms. Our results suggest that preventive stabilisation of CS in RA leads to acceptable results, although the complications of the surgery are obvious. However, early operative treatment may delay the detrimental course of cervical myelopathy in RA.     

Synovial cyst at the C1-C2 junction in a patient with atlantoaxial subluxation

Synovial cysts of the cervical spine causing myelopathy are rare. The pathogenesis of these cysts is often attributed to degenerative changes of the facet joints or microtrauma. The authors report a synovial cyst at the C1-C2 junction in a patient with atlantoaxial subluxation without a congenital anomaly or inflammatory conditions. A 72-year-old man presented with a progressive right-sided myelopathy attributed to a C1-C2 synovial cyst accompanied by atlantoaxial subluxation and C3-C6 spondylosis. Magnetic resonance imaging of the cervical spine showed a large cystic mass compressing the spinal cord located at the C1-C2 junction. A C1 hemilaminectomy, complete evacuation of the cyst contents, and posterior atlantoaxial fusion were performed, and a double-door laminoplasty was also done at C3-C6. The patient showed significant improvement of paresthesia and motor weakness of the right upper and lower extremities immediately after the operation. Synovial cysts should be considered in the differential diagnosis of an extradural mass of the upper cervical spine. Posterior fusion combined with direct excision of the cyst may be the optimum treatment of a synovial cyst at the C1-C2 junction in a patient with atlantoaxial subluxation.     

Rheumatoid Arthritis of the Cervical Spine

Cervical involvement in patients with rheumatoid arthritis occurs primarily in the upper cervical spine. The characteristic deformities are atlantoaxial subluxation, vertical settling, and subaxial subluxation. The typical patient complaints are neck pain and occipital pain. Subtle signs of myelopathy may also be present. Useful radiologic studies include plain radiography, tomography, and functional magnetic resonance imaging. The most helpful radiographic measurements are the anterior atlantodens interval, the posterior atlantodens interval, and assessment of vertical settling. Atlantoaxial subluxation greater than 9 mm with vertical settling and a posterior atlantodens interval less than 14 mm correlate with neurologic deficit. Nonoperative management does not change the natural history of cervical disease. Traditional surgical indications include intractable pain and neurologic deficit. The author discusses more controversial indications and proposes a rationale and protocol for treatment. The primary surgical objectives are to achieve stabilization of the affected segments and to relieve neural compression by reduction of subluxations or direct decompression. Arthrodesis provides reliable pain relief. Neurologic recovery occurs more consistently in patients with lower grades of preoperative myelopathy.     

Predictors of aggravation of cervical spine instability in rheumatoid arthritis patients: the large joint index

Background

Improved rheumatic drugs have provided significant benefits, but activities of daily living are not improved if spinal symptoms are overlooked. Furthermore, the appropriate timing for examining the cervical spine during follow-up is unclear.

Methods

To evaluate the relations of cervical spine instabilities and an index for cervical spine lesion in rheumatoid arthritis (RA) based on extremity radiographs, we examined preoperative radiographs of 100 RA patients who underwent total knee arthroplasty. Radiographic results for eight large joints (bilateral shoulders, elbows, hips, and knees) were graded as follows: Larsen grade ≥2 for each joint was scored as 1 point, which we refer to as the “large joint index” (LJI), based on 0–8 points. The associations of radiographic cervical lesions with LJI, Ranawat class, the disease duration, RA drugs, or blood analysis data were evaluated.

Results

Atlantoaxial subluxation (AAS) (≥5 mm) was found in 45 patients, vertical subluxation (VS) (≤13 mm) in 42, a posterior atlantodental interval (PADI) (<14 mm) in 21, and subaxial subluxation (SAS) (≥3 mm) in 23. Most patients with a PADI < 14 mm (19/21, 90%) were complicated with both AAS and VS. LJI had a significant association with AAS (P < 0.0001), VS (P < 0.01), and PADI (P < 0.01). The PADI was significantly lower (P < 0.0001) and the LJI was significantly higher (P < 0.01) in patients of Ranawat class II compared to patients of Ranawat class I. The disease duration, age at surgery, and age at onset were also significantly associated with cervical instabilities.

Conclusions

PADI should be recognized as a predictor of paralysis with anteroposterior instability and vertical and middle-low cervical spine instability. The LJI proposed in this study has the possibility of being a predictor of cervical lesions. Patients with RA onset at a young age and a long disease duration also have a risk of progression of cervical spine instability.     

The cervical spine in juvenile chronic arthritis.

BACKGROUND CONTEXT: In patients with juvenile chronic arthritis (JCA) the cervical spine is often affected, leading to pain and functional limitations. PURPOSE: To describe the frequency of the radiographic abnormalities in the cervical spine of a large series of patients with JCA, examined after skeletal maturity. STUDY DESIGN: Consecutive patients with JCA, who had cervical spine radiographs available taken at adult age (>18 years) were included in the study from one outpatient clinic and one rheumatology ward in the Rheumatism Foundation Hospital, Heinola, Finland. PATIENT SAMPLE: The series consisted of 159 patients fulfilling the diagnostic criteria of the European League Against Rheumatism for JCA. OUTCOME MEASURES: Evaluation of cervical spine radiographs for inflammatory changes. METHODS: Inflammatory changes in the cervical spine radiographs were measured as well as the size of the fourth cervical vertebra. Patient records were studied. The statistical analysis was calculated by Student's t-test or Mann-Whitney U test. RESULTS: In 98 cases (62%) some inflammatory changes were detected in the cervical spine. Apophyseal joint ankylosis was noted in 65 patients (41%), anterior atlantoaxial subluxation in 27 (17 %) and atlantoaxial impaction in 39 (25 %). The fourth cervical vertebra was abnormally small in 41 patients (26%). CONCLUSIONS: Radiographically, the most frequent inflammatory change in the cervical spine of patients with JCA was apophyseal joint ankylosis at multiple levels. Atlantoaxial impaction and anterior atlantoaxial subluxation were typical of the upper cervical spine. Clinically, these changes tend to limit neck movements. A small C4 vertebral body was seen in patients with early disease onset and short body stature.     

Sagittal alignment of the subaxial cervical spine after C1-C2 transarticular screw fixation in rheumatoid arthritis

Several articles reported the association between the development of subaxial kyphosis and the hyperlordotic fixation of C1-C2. However, their patients were heterogeneous in both primary disease and operative procedure. Transarticular screw fixation has become a popular procedure for C1-C2 arthrodesis instead of wiring techniques in which C1-C2 is difficult to fix in the intended alignment. Furthermore, in rheumatoid arthritis (RA) patients, subaxial lesions play an important role in potential subaxial alignment changes. The subaxial influences after C1-C2 transarticular screw fixation in patients with RA are unclear. To investigate the radiographic features of the subaxial cervical spine after C1-C2 transarticular screw fixation for RA, we reviewed 28 cases of C1-C2 transarticular screw fixation for rheumatoid atlanto-axial subluxation. The sagittal alignment of C1-C2 and the subaxial cervical spine was measured and the factors that affect subaxial alignment were investigated. Subaxial alignment became less lordotic in the postoperative course. The C1-C2 fixation angle and subaxial alignment showed a negative linear correlation. However, no significant correlation was found between changes in the C1-C2 angle and changes in the subaxial alignment. Four patients had a postoperative kyphotic subaxial deformity. Neurologic deterioration recurred in 4 patients, because of the postoperative development of subaxial subluxation. Common radiographic changes included an increase in C1-C2 lordosis, constant inclination of C1, an anterior shift of C2, and a decrease in C2-C7 lordosis. Many factors, not only C1-C2 angle, are associated with subaxial sagittal alignment change after C1-C2 transarticular screw fixation.     

Transoral anterior approach for extensive anterior decompression at the C3 vertebra level in a patient with severe atlantoaxial vertical subluxation and rheumatoid arthritis

STUDY DESIGN: We report a successful extensive transoral anterior decompression for an elderly patient with myelopathy and occipitalgia due to severe atlantoaxial vertical subluxation and posterior subluxation of the axis associated with rheumatoid arthritis (RA). OBJECTIVE: To describe the treatment of an exceptional pathological condition involving severe vertical subluxation. SETTING: University-affiliated hospital in Gifu, Japan. METHODS: A 73-year-old woman was referred to our clinic because of myelopathy and occipitalgia due to severe atlantoaxial vertical subluxation and posterior subluxation of the axis associated with RA. Plain radiographs revealed severe atlantoaxial vertical subluxation and sagittal magnetic resonance (MR) imaging revealed severe compression of the spinal cord at the level of the C2/3 disc space due to both posterior subluxation of C2 and rheumatoid pannus at the C2/3 disc space. As MR images demonstrated that the C2/3 disc space was located just behind the retropharyngeal wall, we performed successful anterior decompression from C2 to C3 via the standard transoral approach without mandibular osteotomy. RESULTS: The patient has been followed for 4 years and her symptoms are currently much improved without further surgical treatment. CONCLUSIONS: The present case illustrates that severe atlantoaxial vertical subluxation and posterior subluxation of the axis associated with RA can be treated successfully by anterior decompression of C2 and C3 via the standard transoral approach.     

寰枢椎后路融合角度与下位颈椎曲度的相关性研究

目的 评价寰枢椎后路融合角度与术后下位颈椎矢状面曲度之间的联系并确定最佳的寰枢椎固定角度以保护颈椎生理曲度.方法 对1995年2月至2005年6月因寰枢椎脱位而行后路C1,C2融合术的92例患者进行术后随访.术前测量颈椎侧位片C1-C2,C2-C7夹角,并且进行术后长期随访,以观察术后随访C1-C2,C2-C7夹角之间的相关性. 结果所有患者均获得随访,时间2.0～10.3年,平均5.2年.术前及术后随访时C1-C2夹角平均值分别为18.4°±9.3°、26.0°±6.8°,差异有统计学意义(t=10.4,P<0.05);术前及术后随访时C2-C7夹角平均值分别为14.5°±10.1°、5.6°±12.0°,差异有统计学意义(t=6.0,P<0.05);其中术后随访C1-C2固定角度<20°(10°～20°)共计30例,≥20°(20.0°～43.6°)共计62例.C1-C2固定角度<20°者,术后随访C1-C2角度与C2-C7夹角之间无明确的相关性;C1-C2固定角度≥20°者,术后随访C1-C2角度与C2-C7夹角之间存在线性负相关;C1-C2术前、术后随访夹角的变化值与C2-C7术前、术后随访夹角的变化值之间也存在线性负相关. 结论寰枢关节行后路手术固定于高度前凸位时将导致术后下位颈椎的脊柱后凸,并且固定角度越大,下位颈椎的后凸程度就越大;为了保持下位颈椎的生理性曲度,手术中应尽量将C1-C2固定的角度控制在10°～20吨围内.     

Atlantoaxial subluxation in Reiter's syndrome. A report of three cases and review of the literature

Three patients with the unusual manifestation of atlantoaxial subluxation in Reiter's syndrome are studied. Each patient had mild symptoms referable to the cervical spine and radiologic evidence of erosive disease elsewhere in the skeleton. One patient had an 11-year history of Reiter's syndrome when the atlantoaxial subluxation was detected. The other two had atlantoaxial subluxation detected within 1 year of initial presentation, at variance with three other such patients that were reported previously, in whom there was a 6- to 10-year interval from initial presentation until radiographic documentation of atlantoaxial subluxation. Cervical spine radiographs, including flexion and extension views, are recommended for all patients with Reiter's syndrome and cervical spine symptoms.     

The prevalence of cervical spondylolisthesis.

This study assessed the prevalence of cervical spondylolisthesis in patients undergoing radiographic studies for reasons unrelated to their cervical spine. Scout lateral cervical spine radiographs of 174 patients who had barium swallows were reviewed for the degree and level of cervical spondylolisthesis. Nine patients were found to have >2 mm of anterior subluxation of the cervical spine for a prevalence of 5.2%. Two patients had involvement at the C2-C3 level, one patient at C3-C4, four patients at C4-C5, one patient at C5-C6, and one patient at C7-T1. Subluxation ranged from 2 to 4 mm. Posterior subluxation (retrolisthesis) was not found in any patient. None of the nine patients with spondylolisthesis had complaints of neck pain or upper extremity symptoms, and none had a history of rheumatoid arthritis or cervical trauma.     

Conservative management of idiopathic anterior atlantoaxial subluxation without neurological deficits in an 83-year-old female: A case report

Atlantoaxial subluxation that is not related to traumatic, congenital, or rheumatological conditions is rare and can be a diagnostic challenge. This case report details a case of anterior atlantoaxial subluxation in an 83-year-old female without history of trauma, congenital, or rheumatological conditions. She presented to the chiropractor with insidious neck pain and headaches, without neurological deficits. Radiographs revealed a widened atlantodental space (measuring 6 mm) indicating anterior atlantoaxial subluxation and potential sagittal atlantoaxial instability. Prompt detection and appropriate conservative management resulted in favourable long-term outcome at 13-months follow-up. Conservative management included education, mobilizations, soft tissue therapy, monitoring for neurological progression, and co-management with the family physician. The purpose of this case report is to heighten awareness of the clinical presentation of idiopathic anterior atlantoaxial subluxation without neurological deficits. Discussion will focus on the incidence, mechanism, clinical presentation, and conservative management of a complex case of anterior atlantoaxial subluxation.