Tehran University Medical Journal

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This was a retrospective review of a consecutive series of patients with spinal disease in year 2000, who underwent posterior fusion and instrumentation with Harrington distraction and Cotrel-Dobousset system to evaluate causes of hardware failure. Many cases of clinical failure has been observed in spinal instrumentation used in spinal disorder like spondylolisthesis, fractures, deformities, … . Thirty six cases that were operated because of spinal disorders like spondylolisthesis, fractures, deformities, …, were included in this study. Seventeen of this cases had breakage of device. Factors like age at surgery, type of instrumentation, angles before and after surgery and …, were compared in two groups of patients. The most common instrument breakage was pedicle screw breakage. Pseudoarthrosis was the main factor that was presented in failure group (P value<0.001). Other important causes were, age of patient at surgery (P value=0.04), pedicle screw placement off center in the sagittal or coronal plane of the pedicle (P value=0.04). Instrumentation loads increased significantly as a direct result of variations in surgical technique that produce pseudoarthrosis, pedicle screw placement off center in the sagittal plane of the pedicle, or using less than 6 mm diameter screw. This factor can be prevented with meticulous surgical technique and using proper devices.

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Background: Congenital scoliosis is a developmental disorder defined as a lateral curvature of the spine. Its progressive trend and complications, such as cosmetic problems, pain and pulmonary symptoms, have put scoliosis as an important skeletal deformity that should be corrected. One of the currently accepted methods of treatment is posterior spinal fusion (PSF) that may be performed with or without instrumentation. However, the use of implants in conjunction with PSF in congenital spine deformity has been debated over the past three decades primarily because of increased risk of neurological deficit and implant displacement. The aim of this study was to compare short-term and long-term outcomes of spinal fusion with and without posterior instrumentation in congenital scoliosis.

Methods: In this historical cohort study, 41 patients with congenital scoliosis were recruited. All patients underwent PSF surgery between 1977 and 1996. They were divided into two groups according to the use of instrumentation: 22 congenital scoliotic patients who were treated by PSF without any instrumentation (group A), and 19 instrumented PSF patients (group B). Instrumentation was mostly performed using the Harrington rod. The major curve angle was measured before surgery, two weeks and one year after PSF surgery and at the end of the follow-up period.

Results: The mean baseline curve angles were 66.3° and 69.1° in groups A and B, respectively. The mean Cobb angles one year after PSF were 43.1° and 38.4° in groups A and B, respectively. The mean follow-up period was 8 years (SD=3) and, at the end of this period, the final Cobb angles were 47.3° and 39.4° in groups A and B, respectively. Therefore, the final angle correction was 28.7% in patients without instrumentation and 43% in patients with instrumentation. The mean loss of correction was 5.5% and 4.3% in groups A and B, respectively. The final curve angles was significantly more corrected for those patients in whom instrumentation was used than those without instrumentation (p<0.05).

Conclusion: The treatment of congenital scoliosis can be very challenging despite the benefits of modern surgeries and instrumentation methods. The results of our study demonstrate that the application of an implant with PSF surgery may lead to increased improvement of the scoliotic curvature in the short-term and long-term periods, as well as a decrease in the loss of correction and the rate of reoperation. In addition, the low incidence of complications in our study indicates the safety of the posterior instrumentation for the treatment of congenital scoliosis.

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Background: Degenerative spondylolisthesis is a common disease of the lumbar spine especially in older ones. The disease represents a challenge to the treating physician. At present, for those patients that deteriorate clinically, there are many proposed algorithms for the surgical treatment. This before and after study was undertaken to assess the surgical results of decompression and instrumented posterolateral fusion in these patients.

Methods: The study population consisted of 23 patients who had undergone no prior surgery for degenerative spondylolisthesis on the lumbar spine. These patients were treated by decompression, bilateral posterolateral fusion, and segmental (pedicle screw) instrumentation with mean follow-up of 29 months (range, 13-73 months). Finally, The clinical results were evaluated for all patients by means of an Oswestry Disability Index (ODI) version 2.1, the Henderson's functional capacity, and persistence of leg symptoms, low back pain or claudication. Mann-Whitney and Chi-Square tests were used to assess the average values and comparison, respectively.

Results: Henderson's functional capacity at the last visit session was excellent in 14 (60.9%), good in 7 (30.4%), fair in 2 (8.7%) cases. ODI decreased from 72.2% (50-88%) preoperatively to 14.4% (0-54%) at the latest follow-up visit. A history of leg pain or claudication was correlated significantly with the amount of decline in ODI score and Henderson's functional capacity (p<0.05).

Conclusion: In spite of limited number of our patients, decompressive surgery plus instrumented posterolateral fusion is a safe, reliable, and satisfactory procedure for treating degenerative lumbar spondylolisthesis. This procedure may be done when conservative treatment was failed and psychological problems can be ruled out.