Clinical and Radiological Outcome of an Interspinous Dynamic Stabilization System in Degenerative Lumbar Disease:24 Cases with Over 24 Months of Follow-up

OBJECTIVE: The purpose of this study was to analyze the clinical and radiological outcomes of dynamic stabilization with DIAM implants. METHODS: We evaluated 24 cases in which lumbar decompressive surgery was performed with dynamic stabilization using DIAM and having more than 24 months of follow up. Indications consisted of spinal stenosis with or without a herniated disc and transition level stenosis of the instrumented fusion segment. Operative data, clinical outcome, and plain and flexion/extension radiographs were obtained and compared to preoperative and postoperative data. RESULTS: The mean age at operation was 56.2 years(range 47-68); the mean follow-up duration was 28.4 months(range 24-37 months).The mean pain and function scores improved significantly from baseline to follow-up, as follows: back pain VAS score from 6.2 to 2.5, leg pain VAS score from 7.2 to 2.4, and Prolo's economic and functional rating score from 5.8 to 8.2. Radiological data demonstrated that the heights of the intervertebral foramen and the posterior disc increased significantly after the procedure. There were no implant-associated complications except for two spinous process fractures which occurred during DIAM insertion, and one case of wound infection. Flexion instability and spondylolisthesis occurred in two cases during the follow-up period. CONCLUSION: These mid-term results suggest that DIAM is a safe and effective alternative surgical option in the treatment of degenerative lumbar stenosis without flexion instability. Careful follow-up is needed to watch for the development of flexion instability and spondylolisthesis.

Clinical Experience of the Dynamic Stabilization System for the Degenerative Spine Disease

OBJECTIVE: The aim of the present study was to assess the safety and efficacy of the dynamic stabilization system in the treatment of degenerative spinal diseases. METHODS: The study population included 20 consecutive patients (13 females, 7 males) with a mean age of 61+/-6.98 years (range 46-70) who underwent decompression and dynamic stabilization with the Dynesys system between January 2005 and August 2006. The diagnoses included spinal stenosis with degenerative spondylolisthesis (9/20, 45%), degenerative spinal stenosis (5/20, 25%), adjacent segmental disease after fusion (3/20, 15%), spinal stenosis with degenerative scoliosis (2/20, 10%) and recurrent intervertebral lumbar disc herniation (1/20, 5%). All of the patients completed the visual analogue scale (VAS) and the Korean version of the Oswestry Disability Index (ODI). The following radiologic parameters were measured in all patients : global lordotic angles and segmental lordotic angles (stabilized segments, above and below adjacent segments). The range of motion (ROM) was then calculated. RESULTS: The mean follow-up period was 27.25+/-5.16 months (range 16-35 months), and 19 patients (95%) were available for follow-up. One patient had to have the implant removed. There were 30 stabilized segments in 19 patients. Monosegmental stabilization was performed in 9 patients (47.3%), 9 patients (47.3%) underwent two segmental stabilizations and one patient (5.3%) underwent three segmental stabilizations. The most frequently treated segment was L4-5 (15/30, 50%), followed by L3-4 (12/30, 40%) and L5-S1 (3/30, 10%). TheVAS decreased from 8.55+/-1.21 to 2.20+/-1.70 (p<0.001), and the patients' mean score on the Korean version of the ODI improved from 79.58%+/-15.93% to 22.17%+/-17.24% (p<0.001). No statistically significant changes were seen on the ROM at the stabilized segments (p=0.502) and adjacent segments (above segments, p=0.453, below segments, p=0.062). There were no patients with implant failure. CONCLUSION: The results of this study show that the Dynesys system could preserve the motion of stabilized segments and provide clinical improvement in patients with degenerative spinal stenosis with instability. Thus, dynamic stabilization systems with adequate decompression may be an alternative surgical option to conventional fusion in selected patients.

The Results of Posterior Lumbar Inter-body Fusion using PEEK Cage andPedicle Screw Stabilization in Degenerative Lumbar Spinal Disorders / 대한정형외과학회잡지

PURPOSE: To evaluate the results of posterior lumbar interbody fusion (PLIF) using PEEK cage with local laminectomized bone and pedicle screws stabilization in multiple segment degenerative lumbar spinal disorders. MATERIALS AND METHODS: We performed a retrospective analysis (1 yr follow-up examination) on 152 patients with PLIF using PEEK cage. The 152 patients, were sub-categorized as follows: 1) group A - one level fusion (80 cases), 2) group B - two level fusion (60 cases), and 3) group C - three level fusion (12 cases). We compared each group based on operation time, amount of bleeding, number of complications, sagittal alignment, fusion rate, adjacent segment problems, and evaluation of the clinical result as per the criteria in Kim et al (1991). RESULTS: For operation time group A took 190.25+/-40.89 min, group B took 230.46+/-39.13 min, and group C took 243.25+/-39.13 min (p=0.08). Furthermore, amount of bleeding for group A was 1,140+/-704 ml, group B was 1,328+/-776 ml, and group C was 1,688+/-756 ml (p=0.07). Consequently, no significant difference was observed between each group. For lumbar lordosis, segmental lordosis, anterior and middle disc height, the last follow-up value was significantly greater than the preoperative value in all three groups. For the adjacent segmental problem, group A had 6 cases, group B had 6 cases, and group C had 2cases. The clinical result revealed a good result in 93.25% for group A, 91.67% for group B, 91.67% for group C. In addition, the fusion rate was 93.75% for group A, 95.00% for group B, and 91.67% for group C. Moreover, the number post-operative complication cases for group A totaled 2 postoperative infections with metal loosening, 5 non-union, and 2 hematomas. Group B had 1 postoperative infection with metal loosening, 3 nonunion, 1 dural tear, and 1 incomplete root injury. Lastly, in group C, 1 complete root injury occurred. CONCLUSION: A PLIF using PEEK cage with local laminectomized bone and posterior pedicle screw stabilization in multiple segments should be considered to be a useful surgical method as a result of favorable clinical results and a fusion rate similar to the rate of a single segment.