Kyung-Chung Kang

Ossification of the ligamentum flavum of the thoracic spine in the Korean population

OBJECT Thoracic ossification of the ligamentum flavum (OLF), a main cause of thoracic myelopathy, is an uncommon disease entity. It is seen mostly in East Asia, although the majority of reports have issued from Japan. In the present study, the clinical features and prognostic factors of thoracic OLF were examined in a large number of Korean patients. METHODS Data from 51 consecutive patients who underwent decompressive laminectomy with or without fusion for thoracic OLF between 1998 and 2008 were retrospectively analyzed. Patients were evaluated pre- and postoperatively using the modified Japanese Orthopedic Association (JOA) scale (maximum total score of 11). Patient age, sex, preoperative symptoms, duration of initial symptoms, number of involved segments, duration of follow-up, presence of dural adhesion (dural tearing), intramedullary high signal intensity, morphological classification of OLF (axial or sagittal), coexisting disease, and fusion or no fusion were also evaluated. Surgical outcomes were assessed using JOA recovery rate/outcome scores, and patient satisfaction grades and prognostic factors were analyzed. RESULTS There were 18 men and 33 women with a mean age of 60.9 years (range 38-80 years). A mean preoperative JOA score of 5.5 improved to a mean score of 7.4 at the last follow-up (mean 52 months after surgery). The mean duration of the initial symptoms was 34.5 months (range 0.1-240 months) prior to surgery. The most common symptoms were motor dysfunction (80%); sensory deficit (67%); and pain, numbness, and claudication (59%) in the lower extremities. Knee hyperreflexia appeared in 69% of the patients. There were a total of 130 ossified segments, and the mean number of segments per patient was 2.6. Ninety-two (71%) of 130 segments were located below T-8. Recovery outcomes were good (18 patients), fair (16 patients), unchanged (11 patients), or worse (6 patients). Thirty-one patients (61%) were satisfied with their operations. Patients with a beak type of OLF on sagittal MR images experienced a higher recovery rate and a better satisfaction grade than did those with a round OLF. The patients with higher preoperative JOA scores demonstrated significantly higher JOA scores postoperatively (p < 0.001), and the preoperative JOA score had a significant correlation with the recovery rate in patients exhibiting mainly motor dysfunction (p = 0.040, r = 0.330). CONCLUSIONS Of the thoracic OLF studies published to date, the present analysis involves the largest Korean population. The most common symptoms of thoracic OLF were motor dysfunction and sensory deficit in the lower extremities, although pain, numbness, and claudication were observed in some patients and were notably accompanied by knee hyperreflexia. At a minimum of 2 years after surgery for thoracic OLF, operative outcomes were generally good, and the prognostic factors affecting good surgical outcomes included a beak type of OLF and a preoperative JOA score > 6.

Changes of upper thoracic curve and shoulder balance in thoracic adolescent idiopathic scoliosis treated by anterior selective thoracic fusion using VATS.

Study Design A retrospective radiographic analysis. Objectives To evaluate changes of upper thoracic curve and shoulder balance in thoracic adolescent idiopathic scoliosis patients treated by anterior selective thoracic fusion using video-assisted thoracoscopic surgery and to identify adequacy of earlier criteria of double thoracic (DT) curve for anterior correction. Summary of Background Data Although anterior and posterior scoliosis correction show many differences in correction mechanisms, fusion levels, loss of correction etc., the criteria of DT curve was applied without differences. There are no reports about these differences. Materials and Methods Forty patients were followed for a minimum of 3 years (range, 3-8 y). The magnitude and flexibility of upper thoracic, lower thoracic, and the superior portion of the lower thoracic curve were measured using full length standing and side-bending radiographs before surgery, at 1 week postoperatively, and at last follow-up. The correction rate and loss of correction of these curves were calculated and preoperative and postoperative radiographic shoulder heights (RSHs) were measured. RSH was defined as balanced (shoulder height difference <10 mm), mildly imbalanced (10-20 mm), or moderately imbalanced (>20 mm). T1 tilt and coronal balance were also evaluated. Patients were divided into groups based on these factors and postoperative RSH was compared. Results Flexibility of the upper thoracic curve was 46% and magnitude of the upper thoracic curve was corrected spontaneously from 28.6±7.8 degrees to 17.9±7.0 degrees with a 37.4% correction rate that did not change during follow-up. On average, preoperative left shoulder was 6.3±10.5 mm lower than right shoulder and this changed to 10.4±11.8 mm and 6.0±8.2 mm higher than right shoulder at 1 week postoperatively and at last follow-up, respectively. The group with an upper thoracic curve of ≥30 degrees or a superior portion of the lower thoracic curve of ≥30 degrees preoperatively had a higher left shoulder postoperatively (P=0.016, 0.040). Of the 12 patients with a symmetric or higher left shoulder (≥0 mm) preoperatively, 9 patients had a balanced shoulder (−10-10 mm) and 3 patients showed mild shoulder imbalance (<20 mm) at last follow-up. Conclusions Among patients who have DT curve, patients with mild left shoulder elevation (<20 mm) can be treated by anterior correction unless the magnitude of upper thoracic curve or superior portion of lower thoracic curve are ≥30 degrees. For anterior correction, criteria of DT curve might be applied less strictly.

The factors that influence the postoperative segmental range of motion after cervical artificial disc replacement

BACKGROUND CONTEXT Advantages of cervical artificial disc replacement (ADR) are to preserve segmental range of motion (ROM) and avoid adjacent segmental disease. To achieve successful outcome after cervical ADR, ROM maintenance is important, but few authors have investigated the factors that influence the postoperative segmental ROM. PURPOSE To evaluate the factors that influence the postoperative segmental ROM after cervical ADR. STUDY DESIGN/SETTING A retrospective clinical study. PATIENT SAMPLE Forty-one consecutive cervical ADR cases were analyzed. OUTCOME MEASURES Disc height, segmental and overall ROM, and clinical parameters checked with Neck Disability Index (NDI) and visual analog scale (VAS) in neck and arm pain were assessed. METHODS There were 21 men and 20 women with a mean age of 45 years (range, 27-61 years). All cases were followed up for more than 2 years (range, 24-54 months; average, 31 months). Angles of the inserted implant on the immediate postoperative lateral radiographs, segmental and overall ROM (full flexion angle-full extension angle), disc height increment (immediate postoperative disc height-preoperative disc height), and adjacent segment changes at cephalad and caudal disc space were measured. Correlations between the factors and segmental ROM at last follow-up were analyzed. RESULTS Mean preoperative NDI was improved from 61.0 preoperatively to 11.5 at last follow-up, and mean VAS in the neck pain decreased from 56.8 preoperatively to 11.8 postoperatively and arm pain decreased from 68.1 to 18.0. The mean preoperative segmental ROM changed from 7.4+/-3.2 degrees preoperatively to 10.4+/-5.9 degrees at last follow-up, and mean preoperative disc height increased from 6.4+/-1.0 (4.1-8.4) mm preoperatively to 7.9+/-1.0 (6.3-9.9) mm postoperatively. The segmental ROM at last follow-up was not significantly correlated with preoperative segmental and overall ROM, angle of inserted implant, VAS, or age (p>.05). However, the segmental ROM at last follow-up was significantly correlated with the disc height increment (p=.046, r=0.374) and preoperative NDI (p=.026, r=0.412). The patient group with the postoperative segmental ROM greater than 10 degrees had a significantly lower mean preoperative disc height than the group with the segmental ROM less than 10 degrees (p=.050). CONCLUSIONS At a minimum of 2 years after cervical ADR, clinical outcomes were satisfactory in terms of function and pain scores. Within our results, the segmental ROM was not affected by preoperative ROM but postoperative disc height increment positively and preoperative disc height negatively.

Outcomes and Related Factors of C5 Palsy Following Cervical Laminectomy With Instrumented Fusion Compared With Laminoplasty.

Study Design. A retrospective study. Objective. The aim of this study was to analyze the clinical outcomes and related factors of C5 palsy (C5P) following posterior cervical laminectomy with fusion (LF) compared with laminoplasty (LP). Summary of Background Data. C5P is more common after LF than after LP. There have not been any studies on C5P-LF compared with C5P-LP. Methods. We retrospectively analyzed consecutive cases that underwent cervical LF for nontraumatic cervical myelopathy or myeloradiculopathy (CMR). To analyze the related factors, C5P-LF and non-C5P-LF groups were compared. To assess the clinical parameters, preoperative diagnosis, clinical symptoms, surgical procedures, and outcome instruments were analyzed. Radiographically, we analyzed preoperative maximal spinal cord compression ratio, presence of C4–5 foraminal stenosis (FS), and correction angles on the sagittal plane. To compare with C5P-LP, we analyzed the incidence, time of onset, grade of muscle weakness, other accompanying cervical nerve root palsies, recovery time, and degree of final recovery in the C5P-LF and the C5P-LP groups of 100 consecutive LPs. Results. A total of 90 LF patients were enrolled (M:F = 54:36, mean age 61.1 yr, mean follow-up 35 months). C5P occurred in 26 patients (28.9%), and 14 cases (53.8%) demonstrated other cervical nerve root palsies. Clinically significant differences were observed between the C5P-LF and non-C5P-LF groups with regard to preoperative clinical diagnosis (CMR 88.5:42.2%, P < 0.001) and presence of preoperative upper extremity weakness (57.7:32.3%, P = 0.02). Comparison between the C5P-LF and C5P-LP groups showed significant differences between incidence (28.9:4%), mean grade of weakness (2.1:3.5), accompanying nerve root symptoms (53.8:0%), recovery time (20.8:10.5 weeks), and incidence of incomplete recovery (15.4:0%). Conclusion. C5P-LF patients showed higher incidence, more severe weakness, frequent involvement of multiple cervical nerve roots, and longer recovery time than C5P-LP patients. Preoperative clinical manifestation of CMR and preexisting upper extremity weakness were the related factors of C5 palsy. Level of Evidence: 3

How does back muscle strength change after posterior lumbar interbody fusion

OBJECTIVE There is a lack of evidence of how back muscle strength changes after lumbar fusion surgery and how exercise influences these changes. The aim of this study was to evaluate changes in back muscle strength after posterior lumbar interbody fusion (PLIF) and to measure the effects of a postoperative exercise program on muscle strength and physical and mental health outcomes. METHODS This prospective study enrolled 59 women (mean age 58 years) who underwent PLIF at 1 or 2 spinal levels. To assess the effects of a supervised lumbar stabilization exercise (LSE), the authors allocated the patients to an LSE (n = 26) or a control (n = 33) group. The patients in the LSE group performed the LSEs between 3 and 6 months postoperatively. Back extensor strength, visual analog scale (VAS) scores in back pain, and physical component summary (PCS) and mental component summary (MCS) scores on the 36-Item Short Form Health Survey were determined for the both groups. RESULTS Mean strength of the back muscles tended to slightly decrease by 7.5% from preoperatively to 3 months after PLIF (p = 0.145), but it significantly increased thereafter and was sustained until the last follow-up (38.1%, p < 0.001). The mean back muscle strength was similar in the LSE and control groups preoperatively, but it increased significantly more in the LSE group (64.2%) than in the control group (21.7%) at the last follow-up 12 months after PLIF (p = 0.012). At the last follow-up, decreases in back pain VAS scores were more significant among LSE group patients, who had a pain reduction on average of 58.2%, than among control group patients (reduction of 26.1%) (p = 0.013). The patients in the LSE group also had greater improvement in both PCS (39.9% improvement) and MCS (20.7% improvement) scores than the patients in the control group (improvement of 18.0% and 1.1%, p = 0.042 and p = 0.035, respectively). CONCLUSIONS After PLIF, strength in back muscles decreased until 3 months postoperatively but significantly increased after that period. The patients who regularly underwent postoperative LSE had significantly improved back strength, less pain, and less functional disability at 12 months postoperatively.

A Broken Drill-bit Fragment Causing Severe Radiating Pain after Cervical Total Disc Replacement: A Case Report.

This is a case report of a 38-year-old man with severe radiating pain on upper extremity after cervical total disc replacement (TDR). We faced an unusual complication that has not been reported yet. He underwent cervical TDR for left central disc protrusion on C5-6. After the surgery, preoperative symptom disappeared. However, at postoperative 1 year, he complained severe right-sided radiating pain that had a sudden onset. On postoperative X-ray, a metal fragment which seemed like a broken drill bit was shown within the spinal canal. To remove that, right-sided anterior microforaminotomy on C5-6 was performed and the metal fragment was removed successfully. After that, anterior fusion was done because the motion of the artificial disc was minimal and the removed structure seemed to attenuate stability during cervical motion. The operation resulted in prompt symptomatic relief. During cervical TDR, particular attention should be paid to the procedures that require using drill-bits.

Incidence of microbiological contamination of local bone autograft used in posterior lumbar interbody fusion and its association with postoperative spinal infection.

OBJECTIVE The aim of this study was to examine the results of microbiological cultures from local bone autografts used in posterior lumbar interbody fusion (PLIF) and to identify their association with postoperative spinal infection. METHODS The authors retrospectively evaluated cases involving 328 patients who had no previous spinal surgeries and underwent PLIF for degenerative diseases with a minimum 1-year follow-up. Local bone was obtained during laminectomy, and microbiological culture was performed immediately prior to bone grafting. The associations between culture results from local bone autografts and postoperative spinal infections were evaluated. RESULTS The contamination rate of local bone was 4.3% (14 of 328 cases). Coagulase-negative Staphylococcus (29%) was the most common contaminant isolated, followed by Streptococcus species and methicillin-sensitive Staphylococcus aureus. Of 14 patients with positive culture results, 5 (35.7%) had postoperative spinal infections and were treated with intravenous antibiotics for a minimum of 4 weeks. One of these 5 patients also underwent reoperation for debridement during this 4-week period. Regardless of the microbiological culture results, the infection rate after PLIF with local bone autograft was 2.4% (8 of 328 cases), with 5 (62.5%) of 8 patients showing positive results on autograft culture. CONCLUSIONS The incidence of contamination of local bone autograft during PLIF was considerable, and positive culture results were significantly associated with postoperative spinal infection. Special attention focused on the preparation of local bone for autograft and its microbiological culture will be helpful for the control of postoperative spinal infection.

Myelopathy-mimicking symptoms of epidural venous engorgement and syringomyelia due to inferior vena cava stenosis at the thoracolumbar junction in a patient with Budd-Chiari syndrome.

Epidural venous engorgement can result from various lesions, such as arteriovenous malformation, thrombosis or occlusion of the inferior vena cava (IVC), or an abdominal masslike lesion. Most patients with these problems complain of low-back pain, radicular pain, or neurogenic claudication, which are symptoms suggestive of disc herniation or spinal stenosis. However, these patients rarely exhibit neurological deficits or cauda equina syndrome. The authors encountered a case of a 60-year-old man presenting with lower-extremity weakness and voiding difficulty for a period of 1 year. To investigate the patients myelopathy-mimicking symptoms, a lumbar spine MRI scan was performed. The MR images exhibited tortuous and dilated spinal vessels compressing the spinal cord and thecal sac at the T11-L3 level, which were concurrent with syringomyelia evidenced by a 22 × 2.5-mm cyst at the T11-12 level. 3D CT scanning of the whole aorta revealed total occlusion and regression of the IVC in the intrahepatic region 3 cm inferior to the right atrium and dilation of multiple collateral veins. The patient was diagnosed with chronic Budd-Chiari syndrome Type I. The authors performed venography, followed by intrahepatic IVC recanalization via stent placement under fluoroscopic and ultra sonographic guidance and without surgical exploration. After this treatment, there was a marked decrease in epidural venous engorgement and the patients symptoms resolved almost completely. This case indicates that epidural venous engorgement at thoracolumbar levels may cause symptoms suggestive of myelopathy and can be successfully treated by minimally invasive procedures to eliminate the underlying causes.