ABSTRACT
Objective:To evaluate the specialty of the clinical features, treatment procedure, clinical outcome, and prognosis in the patients with "sandwich" atlantoaxial dislocation (AAD).Methods:From 2008 to 2018, 160 cases with "sandwich" AAD were retrospectively selected from the case series of AAD in Peking University Third Hospital. The case series had 80 males and 80 females. The mean age at the initial visit was 35.5±14.6 years (range, 5-77). The clinical courses, treatment methodology and prognosis were reviewed. And the surgical approach, posterior fixation segment and the recovery of neurological function were mainly summarized. The atlantodental interval (ADI), the distance by which the odontoid exceeded the Chamberlain line and the cervical-medullary angle were analyzed.Results:The most common symptoms included weakness or numbness of the limbs (67.5%, 108/160), unstable gait (30%, 48/160) and vertigo (20%, 32/160). Among all, 130 cases (81.3%, 130/160) had myelopathy, with the Japanese Orthopaedic Association (JOA) scores from 4 to 16 (mean JOA scores 13.5±2.5). Cranial neuropathy was involved in 20 cases (12.5%). Radiological findings showed brainstem and/or cervical-medullar in 130 cases (81.3%), syringomyelia in 37 cases (23.1%) and Chiari malformation in 30 cases (18.8%). Computed tomography angiography (CTA) was performed in 90 cases, which showed vertebral artery anomalies in 55 cases (61.0%) and excessive medialized internal carotid artery in 5 cases (5.6%). All cases had no spinal cord or vertebral artery injury. The surgery included posterior occipito-cervical fusion (reducible dislocation, 145 cases), and transoral release followed by posterior fusion (irreducible dislocation, 15 cases). Fifty-seven cases were treated using alternative fixation technique. The average follow-up time was 50.5±22.4 months (range, 24 to 120 months). All of 152 cases (95.0%) achieved solid atlantoaxial fusion; there was no obvious osseous fusion formation on postoperative images in 6 cases (3.8%), but no atlantoaxial instability was found on dynamic radiographs; screw loosening happened in 2 patients (1.2%). Nine patients (5.6%) suffered complications, including 4 cases with recurrent dislocation, 2 screw loosening, 2 cases with bulbar paralysis and 1 wound infection. The mean postoperative JOA was 15.1±1.8 (range, 5-17), and the mean neurological improvement rate was 42.9%±33.3% in the patients with myelopathy.Conclusion:"Sandwich" AAD, a subgroup of AAD, has unique clinical features: earlier onset age and more severe myelopathy. The incidence of bone and vascular malformation is higher. So alternative surgical plan and hybrid fixation should be prepared for this subgroup of AAD.
ABSTRACT
Objective To quantitatively compare the effect of preservation or removal of atlas posterior arch on cervical posterior decompression,so as to provide a basis for reasonable selection of upper cervical spine decompression range and determination of surgical indications for atlas posterior arch resection.Methods The data of 45 patients with posterior decompression of upper cervical spine were retrospectively analyzed.According to the decompression range,the patients were divided into C2-C7 group and C1-C7 group.There were 25 cases in the C2-C7 group,19 males and 6 females,with an average age of 56.3 years (40-71 years),4 cases of cervical spondylotic myelopathy and 21 cases of ossification of the posterior longitudinal ligament of cervical spine.All of the 25 patients underwent open-door laminoplasty:20 cases with hinge side anchoring procedure and 5 cases with preservation of the unilateral posterior muscular-ligament complex procedure (titanium cable procedure).There were 20 cases in C1-C7 group,12 males and 8 females,with an average age of 58A years (44-75 years).All of the 20 cases underwent atlas posterior arch resection as well as C2-C7 open-door laminoplasty,including anchoring procedure in 1 case,titanium miniplate procedure in 4 cases,and titanium cable procedure in 15 cases.Standardized vertebral-cord distance (SVCD) at each level from atlas to level C~ was measured on T2-weighted images of MR on the mid-sagittal plane in the neutral position pedormed 3-12 months postoperatively at each individual level.As the main outcomes,the SVCD values obtained at the same level of the two groups were compared between the two groups.Shapiro-Wilk normality test was performed on the SVCD values at C1.2 and C2 levels of two groups.The area under the normal distribution curve of SVCDs was used to calculate the corresponding residual compression rate with different magnitude of compression mass to further discover the difference of the decompression effect between the two groups.Results The SVCD obtained at the level of the anterior arch of atlas (C1),the junction of odontoid process and axis (C1,2) and the middle part of axis body (C2) in the C2-C7 group was 9.91±1.34 mm,8.35±1.27 mm,and 8.22 ±1.43 mm,respectively.The SVCD at the same levels was 11.02±1.60 mm,9.72±1.24 mm,and 9.12±1.11 mm,respectively.SVCDs differed significantly in the above range between the two groups.However,from level C2,3 to C6,7,there was no significant difference in SVCDs between the two groups.The JOA score of group C2-C7 was 11.8±2.7 preoperatively and increased significantly to 14.7±1.8 at 12 months postoperatively(t=-7.006,P＜0.001) with a recovery rate of 57.0％±32.2％.The JOA score of group C1-C7 was 11.7±2.8 preoperatively and increased significantly to 14.2±2.3 at 12 months postoperatively(t=-6.177,P＜0.001) with a recovery rate of 51.9％±32.1％.Conclusion Atlas posterior arch resection can significantly increase the decompression effect of posterior cervical surgery from the anterior arch of atlas to the middle part of axis body,but it would not increase the decompression effect at level C2.3 or below.When the magnitude of the ventral compression factor exceeds the decompression limit (8.5 mm) available with C2-C7 decompression in the range from atlas to the middle of the axis body,extending the decompression range by atlas posterior arch resection is an effective means to achieve adequate decompression.
ABSTRACT
Objective To observe the perioperative complications for metastatic cervical tumor,and explore their possible risk factors.Methods From January 2012 to January 2016,57 patients undergoing surgery for cervical spine metastasis were retrospectively analyzed,who were followed-up for at least 12 months or until death.Data collected included pain (a 10-point visual analogue scale,VAS),Karnofsky performance status score,neurologic status according to Frankel scale,perioperative complications,postoperative mortality and so on.Results The VAS score decreased significantly postoperation (P＜0.001).The Frankel grade was significantly improved (P=0.025).The Karnofsky score was also significantly improved (P＜0.001).The rate of local recurrence was 12.3％.Perioperative mortality rate (30 days after surgery) was 3.5％.Perioperative complication incidence was 24.6％.Univariate analysis found that comorbidity,preoperative Karnofsky score ＜60,multisegmental resection,and intraoperative blood loss ＞300ml were significant risk factors for the complication.Multivariable analysis showed that iIntraoperative blood loss ＞300ml and preoperative Karnofsky score ＜60 were the independent predictors for the complication.Conclusions Surgical management for cervical spinal metastasis is effective in terms of neurological recovery,pain control,and performance status recovery.However,the surgery had a high risk of complications that special attention should be paid to.Furthermore,complications might be related to preoperative Karnofsky score and intraoperative blood loss.