24-Month Prospective Results of a New Cervical Staple in Anterior Cervical Discectomy and Fusion: Quality of Life and Fusion

134S

Proceedings of the NASS 25th Annual Meeting / The Spine Journal 10 (2010) 1S–149S

PURPOSE: We hypothesize that cervical spine geometric parameters differ between asymptomatic and myelopathic patients, and that laminar roof pitch is more accurate than Pavlov-Torg ratio, Matsuura ratio, sagittal anterior-posterior canal diameter and transverse medial-lateral canal diameter in identifying myelopathic patients. STUDY DESIGN/SETTING: This is a retrospective study. PATIENT SAMPLE: We identified two cohorts: (1) asymptomatic controls and (2) symptomatic patients with myelopathy or both myelopathy and radiculopathy. Control patients were from a trauma registry and did not have cervical trauma, prior surgery or signs and symptoms of myelopathy. Myelopathic patients all had correlative compression on imaging, and Nurick score improved postoperatively. OUTCOME MEASURES: Sagittal measurements included (1) anteriorposterior (AP) canal diameter at mid-vertebra and (2) at disc level; (3) AP vertebral body diameter; (4) Pavlov-Torg ratio and (5) disc-level Pavlov-Torg ratio. Axial measurements included (1) laminar roof pitch angle (LRP) and (2) Matsuura ratio, which is AP canal diameter divided by the medial-lateral (ML) canal diameter at mid-pedicle. Mixed parameters are detailed in Table 1. METHODS: A two-way ANOVA using group and vertebral level as factors was followed by Tukey’s posthoc procedure. Receiver-operator analysis was used to study sensitivity and specificity. RESULTS: Eighteen control patients, average age 63.8613.4 years, and nineteen symptomatic patients, average age 60.3611 years, were identified. Neither LRP, Pavlov-Torg ratio nor Matsuura ratio differed between groups (all pO0.05). Transverse ML canal diameter, mid-vertebral and disc-level sagittal AP canal diameter differed between groups (p!0.05; Fig1). Mixed sum, a surrogate for canal perimeter, and mixed area at mid-vertebral and disc levels also differed (p!0.05). Transverse ML canal diameter and the mixed sum of transverse ML and sagittal AP canal diameters had the best combined sensitivities and specificities (Fig2). Transverse ML diameter less than 23.5 mm produced 82% sensitivity and 68% specificity. Mixed sum had 79% sensitivity and 78% specificity with a 36 mm threshold. CONCLUSIONS: Transverse ML canal diameter had the best combined sensitivity and specificity, despite studying spondylotic patients. Mediallateral reserve at the pedicle level may be more important than disc-level arthrosis in spondylotic myelopathy. The cross-sectional area at the midvertebral body and at the disc differed between control and symptomatic patients. This contrasts with prior findings that the canal area did not differ between normal patients and those who experienced cervical SCI. These data emphasize that risk factors for myelopathy and acute SCI may differ. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi: 10.1016/j.spinee.2010.07.345

P70. 24-Month Prospective Results of a New Cervical Staple in Anterior Cervical Discectomy and Fusion: Quality of Life and Fusion Vincent Fiere, MD1, Pierre Bernard2, Olivier Ricart3, Fahed Zairi, MD4; 1 Centre Orthope´dique Santy, Lyon, France; 2Centre Aquitain du Dos, Pessac, France; 3Clinique Ambroise Pare´, Thionville, France; 4Chru Roger Salengro, Lille, France BACKGROUND CONTEXT: Anterior cervical discectomy and fusion (ACDF) is currently by far the most used technique in cervical surgery. Arthrodesis is obtained with a bone graft or an intersomatic spacer generally secured using a screwed osteosynthesis plate. Implantation of cervical plate is time consuming and exposes the patient to additional adverse events which may require more surgery. To maintain the position of the intersomatic spacer and to increase bone fusion while maintaining dynamic compression, a cervical compressive staple has been developed. PURPOSE: To evaluate clinical and radiological results of a new cervical compressive staple used to stabilize a PEEK spacer in ACDF procedure.

STUDY DESIGN/SETTING: Prospective multicenter non comparative study. PATIENT SAMPLE: Patient inclusion criteria consisted of single level cervical disc herniation (at C4-Th1 levels), without previous surgery and with cervicobrachial neuralgias which had not responded to conservative treatment. Eighty-two patients from 5 centers were prospectively included in the study. OUTCOME MEASURES: Preoperative and Postoperative neurological status was evaluated by the Neck Disability Index (NDI) and Visual analogic pain scales (VAS) and general health status by the SF-12. Functional outcome (odom criteria) and patient satisfaction were also considered. Neck disability success was based on the postoperative NDI score being better than pre-operative score by at least 15 points (if preoperative score O30 points) or at least 50% (if preoperative score !30 points). Arm and Neck pain success was defined by at least a 2 point improvement in pain score (in patients with a preoperative score $4) or maintenance of the preoperative score in patients with preoperative score of !4 or less. Radiographic examinations including dynamic flexion-extension and lateral films were used to assess fusion, mobility or signs of pseudarthrosis. METHODS: All patients were treated with an anterior cervical discectomy and fusion using a Peek spacer prefilled with bone substitute (tricalcium phosphate) and secured by the cervical compressive staple. At follow-up, each patient has completed self-questionnaires (NDI, VAS, SF-12 and satisfaction), radiographic control and a clinical evaluation were done. X-rays were reviewed by two independent observers. RESULTS: The average operating time was 35 min (range 30 to 40), and the average stay at hospital was 1.5 days (range 1 to 2 days). 90% of the patients had a solid fusion. Mean NDI score (range) was significantly improved by 20.2 (0–43) preoperatively to 6.6 (0–34) at last follow-up. 87% of the patients reported a NDI success. Mean Neck and Arm pain were significantly improved by 6.1 (0–10) and 7.0 (0–10) to 1.8 (0–8.6) and 2.2 (0–9.5), respectively at last follow-up. 90% and 88% of the patients reported a Neck pain and Arm Pain success respectively. Mean SF-12 Physical Component Summary (PCS) and Mental Component Summary (MCS) scores were significantly improved by 37.0 and 38.4 respectively to 48.9 and 50.9 at last follow-up. 91% of the patients are completely satisfied or satisfied by the surgery and 89% had a successful functional outcome at last follow-up. On the 82 patients, 1 had a preoperative vascular lesion without consequences for the patient, 1 had experimented a transient dysphagia which were relieved at 2 month follow-up. 3 patients had experimented a hardware-related events (2 breakage and 1 minor back-out) without clinical consequences and without revision: all patients reported no complains and X-rays showed solid fusion. 2 revision surgeries were required for pseudarthrosis and 2 additional surgeries for a degeneration at the superior adjacent level. CONCLUSIONS: Patients presented solid fusion with significant pain relief and improvement of their quality of life. Compared to previous data, success rate and occurrence of complication were similar. The staple seems to provide a safe and effective new way to secure an intersomatic spacer with a reduced surgical time. FDA DEVICE/DRUG STATUS: C-JAWS staple: Not approved for this indication. doi: 10.1016/j.spinee.2010.07.346

P71. Changes in Coronal and Sagittal Plane Alignment after XLIF Procedure in the Treatment of Degenerative Scoliosis Leonardo Oliveira, BSc1, Luis Marchi, MSc2, Etevaldo Coutinho, MD2, Luiz Pimenta, MD, PhD2; 1Universidade Federal de Sa˜o Paulo, Sa˜o Paulo, Brazil; 2Instituto de Patologia da Coluna, Sa˜o Paulo, Brazil BACKGROUND CONTEXT: The traditional treatments to degenerative scoliosis consist in open surgeries, with high incidence of morbidity. Here we present a lateral retroperitoneal minimally invasive approach for the treatment of adult scoliosis. Symptomatic adult scoliosis deformity

All referenced figures and tables will be available at the Annual Meeting and will be included with the post-meeting online content.