Kyung Jin Song

Ossification of the Posterior Longitudinal Ligament: A Review of Literature

Ossification of the posterior longitudinal ligament (OPLL) is most commonly found in men, in the elderly, and in Asian patients. The disease can start with mild or no symptoms, but some patients progress slowly to develop symptoms of myelopathy. An accurate diagnosis through the use plain radiograph, computed tomography, and magnetic resonance imaging findings is very important to monitor the development of symptoms and to make decisions regarding a treatment plan. When symptoms are mild and non-progressive, conservative treatments and periodic observations are good enough, but once symptoms of myelopathy are present and neurologic symptoms are progressive, the treatment of choice is surgery to relieve spinal cord compression. Surgical management of OPLL continues to be controversial. Each surgical technique has some advantages and disadvantages, and the choice of operation should be decided carefully with various considerations. The patients neurological condition, location and extent of pathology, cervical kyphosis, presence or absence of accompanied instability, and the individual surgeons experience must be an important factors that should be considered before surgery.

Efficacy of PEEK Cages and Plate Augmentation in Three-Level Anterior Cervical Fusion of Elderly Patients

Background To evaluate the clinical efficacy of three-level anterior cervical arthrodesis with polyethyletherketone (PEEK) cages and plate fixation for aged and osteoporotic patients with degenerative cervical spinal disorders. Methods Twenty one patients, who had undergone three-level anterior cervical arthrodesis with a cage and plate construct for degenerative cervical spinal disorder from November 2001 to April 2007 and were followed up for at least two years, were enrolled in this study. The mean age was 71.7 years and the mean T-score using the bone mineral density was -2.8 SD. The fusion rate, change in cervical lordosis, adjacent segment degeneration were analyzed by plain radiographs and computed tomography, and the complications were assessed by the medical records. The clinical outcomes were analyzed using the SF-36 physical composite score (PCS) and neck disability index (NDI). Results Radiological fusion was observed at a mean of 12.3 weeks (range, 10 to 15 weeks) after surgery. The average angle of cervical lordosis was 5° preoperatively, 17.6° postoperatively and 16.5° at the last follow-up. Degenerative changes in the adjacent segments occurred in 3 patients (14.3%), but revision surgery was unnecessary. In terms of instrument-related complications, there was cage subsidence in 5 patients (23.8%) with an average of 2.8 mm, and loosening of the plate and screw occurred in 3 patients (14.3%) but there were no clinical problems. The SF-36 PCS before surgery, second postoperative week and at the last follow-up was 29.5, 43.1, and 66.2, respectively. The respective NDI was 55.3, 24.6, and 15.9. Conclusions For aged and osteoporotic patients with degenerative cervical spinal disorders, three-level anterior cervical arthrodesis with PEEK cages and plate fixation reduced the pseudarthrosis and adjacent segment degeneration and improved the clinical outcomes. This method is considered to be a relatively safe and effective treatment modality.

Treatment Outcomes of Triplane and Tillaux Fractures of the Ankle in Adolescence

Background To identify the fracture configuration and treatment results for patients with triplane and Tillaux fractures in the ankle joint. Methods A retrospective study was performed on 14 patients with a more than one year follow-up. This study investigated the fracture configuration, concomitant fibula fracture, treatment methods and complications. The treatment outcomes were analyzed using modified Weber protocol. Results Among the 14 cases, 11 were triplane fractures and 3 were Tillaux fractures. Seven were two part triplane fractures, and 4 were three part triplane fractures. Eight were lateral triplane fractures, and 3 were medial triplane fractures. A fibula fracture was accompanied by 7. The fibular fracture comprised of oblique fractures in all cases. A closed and open reduction was performed in 6 and 8 cases, respectively. All but one showed excellent treatment outcomes at the final follow-up. Traumatic arthritis developed in 1 case. Conclusions Precisely detecting the fracture configuration by computed tomography and understanding the injury mechanism have greatly improved the outcomes of triplane fractures and Tillaux fractures of the ankle in adolescent patients.

Contribution of the anterior longitudinal ligament to ossification and growth of the vertebral body: an immunohistochemical study using the human fetal lumbar vertebrae

Using 15 mid-term human fetuses, we examined the role of the spine anterior and posterior longitudinal ligaments (ALL, PLL) in ossification of the lumbar vertebral body. By 18xa0weeks, a pair of calcified tissue or cortical walls had developed on the anterior and posterior sides of the ossification center. These calcified cortical walls were more highly eosinophilic than trabecular or woven bone in the ossification center. Vimentin-positive osteoblasts were arranged in line along the outer surface of the walls. However, few CD68-positive osteoclasts were evident around the walls, suggesting that the calcification in the walls was similar to periosteal ossification. The anterior cortical wall was connected tightly with the ALL by fiber bundles, but the posterior wall was separated from the PLL by the basivertebral (central) vein and loose tissues. Notably, by 30xa0weeks, the anterior cortical wall had become attached to and incorporated into the ALL. Thus, the ALL seemed to act as an active periosteum for ossification. Although our materials were limited in number and stage, we hypothesized that, in contrast to the PLL, the mature anterior cortical wall corresponds to a calcified fibrocartilage adjacent to the ALL and forms a bone–ligament interface maintaining an ossification potential.

Treatment of O dontoid Fractures with Single Anterior Screw Fixation

Purpose : To evaluate the availability and safety of single anterior screw fixation in the treatment of type II and III odontoid process fractures through an analysis of the treatment outcomes. Materials and Methods : This study analyzed 16 patients who underwent surgery between May 1996 and Oct. 2003 by single anterior screw fixation for type II and III odontoid process fractures with at least a 1 year follow up. The radiographic findings such as the fusion rate, union time, changes in the fracture shape, and metal migration were evaluated. In addition, the Robinson modification criteria were used for the clinical assessment. Results : There were 12 and 4 patients with Anderson and DAlonzo type II and type III fractures, respectively. Of the 16 patients, 15 (93%) achieved bony union after an average of 13.8 weeks. There were 2 cases of malunion with a normal range of cervical motion, and 1 case requiring posterior fusion as a result of nonunion. A full range of cervical motion was maintained in 11 cases. Three cases had a limitation of less than 25% and 2 cases had a limitation greater than 25%. Conclusion : Single anterior screw fixation is an effective treatment modality with a high fusion rate and low complication rates. However, precise preoperative planning and technical experience is essential for preventing unwanted complications.

Interobserver Reliability between MRI, CT-myelogram and Myelogram in the Evaluation of Lumbar Spinal Stenosis

Purpose : We designed this study to evaluate the interobserver reliability of magnetic resonance imaging (MRI), post-myelographic computed tomography (CT-myelogram) and myelography for the diagnosis of lumbar spinal stenosis. Materials and Methods : Thirty two patients with lumbar spinal stenosis were evaluated preoperatively by MRI, CT-myelography, and myelography by four observers. For each set of scans, the examiners assessed the presence or absence of; 1) intervertebral disk protrusion, 2) facet arthrosis, 3) ligamentum flavum hypertrophy, and 4) nerve root impingement. The severities of 1) central, 2) lateral, 3) foraminal and 4) entire spinal stenosis were graded using a four-point scale range from 1 (no stenosis) to 4 (severe stenosis). Results : Kappa statistical analysis revealed moderate interobserver agreement in terms of disk protrusion (0.49), nerve root impingement (0.42) and lateral stenosis grade based on MRI. Low levels of agreement were found for facet arthrosis and ligamentum flavum hypertrophy. Relatively higher levels of agreement were found for nerve root impingement, lateral stenosis and entire stenosis, graded by MRI and for central stenosis graded by myelography. Conclusion : The results of this study reflect that MRI showed relatively higher levels of interobserver reliability than the other diagnostic modalities in the evaluation of patients with lumbar spinal stenosis.