Choon Sung Lee

Risk factors for adjacent segment disease after lumbar fusion

The incidence of adjacent segment problems after lumbar fusion has been found to vary, and risk factors for these problems have not been precisely verified, especially based on structural changes determined by magnetic resonance imaging. The purpose of this retrospective clinical study was to describe the incidence and clinical features of adjacent segment disease (ASD) after lumbar fusion and to determine its risk factors. We assessed the incidence of ASD in patients who underwent lumbar or lumbosacral fusions for degenerative conditions between August 1995 and March 2006 with at least a 1-year follow-up. Patients less than 35xa0years of age at the index spinal fusion, patients with uninstrumented fusion, and patients who had not achieved successful union were excluded. Of the 1069 patients who underwent fusions, 28 (2.62%) needed secondary operations because of ASD and were included in this study. In order to identify the risk factors, we matched a disease group and a control group. The disease group consisted of 26 of the 28 patients with ASD, excluding the 2 patients for whom we did not have initial MRI data. Each patient in the disease group was matched by age, sex, fusion level and follow-up period with a control patient. The assumed risk factors included disc and facet degeneration, instability, listhesis, rotational deformity, and disc wedging. The mean age of the 28 patients with ASD requiring surgical treatment was 58.4xa0years, which did not differ significantly from that of the population in which ASD did not develop (58.2xa0years, pxa0=xa00.894). Of the 21 patients who underwent floating fusion, only 1 developed distal ASD. Facet degeneration was a significant risk factor (pxa0<xa00.01) on logistic regression analysis. The incidence of distal ASD was much lower than that of proximal ASD. Pre-existing facet degeneration may be associated with a high risk of adjacent segment problems following lumbar fusion procedures.

Clinical and radiographic outcomes following hinge fracture during open-door cervical laminoplasty

To investigate the clinical and radiographic fate of fractured hinges in open-door cervical laminoplasty, 135 segments of 36 patients who had undergone follow-up for more than two years after open-door cervical laminoplasty due to compressive cervical myelopathy were reviewed clinically and radiographically. Hinge fractures were identified by the intraoperative finding of obvious instability or click sounds (an obvious fracture), or by immediate postoperative computed tomography (CT) images showing a discontinuity of both the inner and outer cortex or a displacement of more than 1mm at the lamina hinge site (an occult fracture). At two years post-surgery, union and displacement of the fractured hinges were evaluated with CT and the clinical outcome was assessed by the Japanese Orthopedic Association (JOA) and Neck Disability Index (NDI) scores. Immediate postoperative CT scans revealed 28 hinge fractures in 16 patients. Only three fractures were identified during surgery, with most being identified on postoperative CT. Nineteen laminae showed non-displaced cortical discontinuity, five were anteriorly displaced by more than 1mm, and four were displaced posteriorly. Twenty-five laminae (89.3%) had achieved union according to the two-year postoperative CT scan. No de novo neurologic symptoms were found to be associated with hinge fracture. The two-year postoperative JOA and NDI scores did not differ significantly between patients with or without a hinge fracture. Most fractures at the hinge site occurred without intraoperative recognition, and usually re-unified without significant displacement or adverse clinical effects. When hinge fractures occur, careful observation without additional intervention is recommended.

Referral patterns and patient characteristics at the first visit to a scoliosis center: a 2-year experience in South Korea without a school scoliosis-screening program

OBJECTIVE The need for scoliosis screening remains controversial. Nationwide school screening for scoliosis has not been performed in South Korea, and there are few studies on the referral patterns of patients suspected of having scoliosis. This study aimed to examine the referral patterns to the largest scoliosis center in South Korea in the absence of a school screening program and to analyze the factors that influence the appropriateness of referral. METHODS The medical records of patients who visited a single scoliosis center for a spinal deformity evaluation were reviewed. Among 1895 new patients who visited this scoliosis center between April 2014 and March 2016, 1211 with presumed adolescent idiopathic scoliosis were included in the study. Patients were classified into 4 groups according to the referral method: non-health care provider, primary physician, hospital specialist, or school screening program. The appropriateness of referral was labeled as inappropriate, late, or appropriate. In total, 213 of 1211 patients were excluded because they had received treatment at another medical facility; 998 patients were evaluated to determine the appropriateness of referral. RESULTS Of the 998 referrals of new patients with presumed adolescent idiopathic scoliosis, 162 (16.2%) were classified as an inappropriate referral, 272 (27.3%) were classified as a late referral, and 564 (56.5%) were classified as an appropriate referral. Age, sex, Cobb angle of the major curve, and skeletal maturity were identified as statistically significant factors that correlated with the appropriateness of referral. The referral method did not correlate with the appropriateness of referral. CONCLUSIONS Under the current health care system in South Korea, a substantial number of patients with presumed adolescent idiopathic scoliosis are referred either late or inappropriately to a tertiary medical center. Although patients referred by school screening programs had a significantly lower late referral rate and higher appropriate referral rate than the other 3 groups, the referral method was not a significant factor in terms of the appropriateness of referral.