Early-Onset Facioscapulohumeral Muscular Dystrophy: Significance of Pelvic Extensor in Sagittal Spinal Imbalance / 대한정형외과학회잡지

An 11-year-old girl with early-onset facioscapulohumeral muscular dystrophy (FSHD) presented with progressive gait disturbance and lumbar hyperlordosis. The motor power of her pelvic extensor muscles was grade 3. Pelvic tilt and hip flexion were markedly increased as determined by gait analysis. This FSHD case is an impressive example of a patient demonstrating the concept that weak pelvic extensor muscles cannot keep the spine upright and balanced. The most important factor in the development of hyperlordosis is the weakness of the pelvic extensor muscles, and the results of gait analysis exquisitely explain the pathophysiology. The patient stands with her spine hyperextended to maintain upright posture by a compensatory mechanism of relatively strong back extensor muscles. Corrective surgery for lumbar hyperlordosis was not considered as it could eliminate the compensatory lumbar hyperextension, thus making the spine of the patient stoop forward through the hip joint during walking, being caused by the weakness of her pelvic extensor muscles.

The Comparison of the Results Between AO Internal Fixator (Long lever-arm) and Screw-Rod System (Short lever-arm) Through Posterior Approach in Unstable Thoracolumbar Fractures / 대한척추외과학회지

STUDY DESIGN: Prospective study. OBJECTIVES: To analyze the outcome of posterior reduction and fixation with the AO internal fixator and with the screw-rod system in unstable thoracolumbar fractures and to investigate differences in effectiveness between the two methods. SUMMARY OF LITERATURE REVIEW: In unstable thoracolumbar fractures, fixation with the AO internal fixator is an effective method for posterior reduction. However, the results of correction are quite variable. MATERIALS AND METHODS: We analyzed 51 patients with unstable thoracolumbar fractures who underwent correction through posterior approach between 1997 and 2003. We divided the patients into two groups: Patients in Group A (25 cases) were treated with the AO internal fixator, and patients in Group B (26 cases) were treated with the screw-rod system. We added transpedicular bone grafts for 17 patients in Group A. We evaluated correction of deformity (anterior and posterior height of vertebral body, sagittal index, disc height), loss of correction, spinal canal clearance, and neurological recovery. RESULTS: Comparing correction of deformity, we saw better results in Group A than in Group B in regards to sagittal index and anterior height of vertebral body. However, we saw a higher degree of correction loss in the anterior height of the vertebral body in Group A. We grafted autogenous bone into the fracture site by transpedicular approach for 17 patients in Group A. We saw less correction loss in the anterior vertebral body height and sagittal index. In regard to spinal canal clearance, we saw better results in Group A (18%) than in Group B (10%). As for neurological recovery, we could not find any statistically significant difference between the two groups. CONCLUSIONS: Through an operative procedure, we could achieve better results in restoration of anterior vertebral height and canal clearance with the AO internal fixator system. Further study is necessary to keep the reduced state of vertebral height.

Scoliosis Correction with Thoracic Pedicle Screws: Posteroanterior C-arm Rotation Method / 대한정형외과학회잡지

Purpose: This study evaluated a practical, safe and accurate method of thoracic pedicle screw insertion for the surgical treatment of scoliosis using the posteroanterior C-arm fluoroscopy rotation method. Materials and Methods: A total of 611 thoracic pedicle screws were inserted in 45 patients using the posteroanterior (PA) C-arm rotation method. CT scans were taken postoperatively in the transverse and sagittal sections to evaluate the pedicle screw placement. Results: A mean preoperative curve of 57.7o was corrected to 17.1o (range, 3o-45o) in the coronal plane. The postoperative CT scans revealed that 10 screws (1.6%) had penetrated the medial cortex by a mean distance of 3.0 mm and 56 screws (9.2%) penetrated the lateral cortex by a mean distance of 3.5 mm. No screw penetrated the inferior or superior cortex in the sagittal plane. However, 21 screws (3.4%) penetrated the anterior cortex. No neurological or vascular complications were encountered, and none of the screws required replacement. Conclusion: Thoracic pedicle screw insertion in scoliosis patients using the posteroanterior C-arm rotation method is a practical, simple and safe technique that allows the en face visualization of both pedicles by rotating the C-arm to compensate for the rotational deformity.

Minimum 4 Year Follow-up Results of Metalon Metal Hip Resurfacing Arthroplasty / 대한정형외과학회잡지

PURPOSE: To report the minimum 4 year follow up results of metal on metal hip resurfacing arthroplasty. MATERIALS AND METHODS: 39 hips from 36 patients, who received hip resurfacing from November 1998 to September 2001 and were followed up for at least 4 years, were enrolled in this study. The average age was 45 years (28-69 years) and the average follow up period was 51.9 months (48-82 months). A clinical evaluation was performed with the Harris Hip Score and gait analysis postoperatively. A radiologic evaluation was performed regularly after surgery using anteroposterior and lateral simple radiographs. The post-operative cobalt-chrome serum concentration was measured and compared using 21 cases of ceramic-on-ceramic total hip arthroplasty as a control group. RESULTS: The Harris Hip Score improved from 61 points (31-74) preoperatively to 96 points (85-99) postoperatively. There were no cases of acetabular loosening, and the average angle of femoral insert to the shaft was 136 degrees with 22 hips (61.1%) being within 130-140 degrees. The 4 year follow-up survival rate was 97.4%. The serum cobalt and chrome levels were higher than the control group (p<0.05). CONCLUSION: Hip resurfacing showed excellent survival rate after a short-term follow-up, but still requires a long-term evaluation with more cases and further metal ion release studies.