퇴행성 요추 질환으로 후방 극돌기간 고정술을 시행받은 환자의 1년 추시 결과

Abstract

Objectives : A transpedicular screw fixation has been introduced as the treatment of choice for stabilization in segmental instability and in cases which need wide decompression due to spinal stenosis. However, there have been some disadvantages such as postoperative back pain through wide muscle dissection, long operative time and adjacent segmental degeneration (ASD). In the present study, the authors present the effectiveness of the posterior interspinous fusion device to replace the pedicle screw fixation.

Materials and Methods : From Jan 2008 to Aug 2009, 40 patients underwent spinal fusion with a posterior interspinous fusion device (Spire, Medtronics, Sofamor Danek, USA) for various degenerative spine diseases. The posterior interspinous fixation was performed with posterior lumbar interbody fusion (PLIF). 36 patients underwent spinal fusion with a pedicle screw fixation. Dynamic lateral radiographs, Visual analogue scale (VAS), and Korean version of the Oswestry disability index (K-ODI) scores were evaluated immediately, 1 month, 6 months, and 12 months after the surgery in both groups. At 6 months, a lumbar computed tomography was checked to identify the bony fusion process.

Results : The surgical level of the SPIRE plate was 19 in L45. The main lumbar spine diseases in the SPIRE plate treated group were as follows; spinal stenosis in 26 patients, degenerative spondylolisthesis (grade I) in 12 patients, and intervertebral disc herniation with severe intervertebral disc height loss in 2. The VAS scores averaged preoperatively 7.16±2.1 and 8.03±2.3 in the patients of the SPIRE and pedicle screw groups, respectively, and improved postoperatively to 1.3±2.9 and 1.2±3.2 in the SPIRE and pedicle screw groups, respectively in 1-year clinical follow ups (p<0.05). The K-ODI decreased significantly in an equal amount in the patients of both groups one year postoperatively (p<0.05). The range of motion at the upper adjacent segments increased significantly after surgery in the pedicle screw group, which did not manifest in the SPIRE group. The Fisher's exact test revealed a higher incidence of developing ASD in the pedicle screw group than the SPIRE group (p=0.029). Of the 40 patients, bone fusion was evaluated in 37 patients (92.5%). One patient complained of sustained back pain, and Lumbar-CT revealed fusion failure and a fracture on the L4 inferior articular process. Two patients showed fusion failure and cage malposition.

Conclusion : Posterior interspinous fusion devices have some advantages such as a good fusion rate with little muscle dissection and simple manipulation. Although the SPIRE plate is placed only on the spinous process, biomechanical strength may be the same as pedicle screws. The SPIRE plate is an alternative device only if commanded under absolute indication.