Yat Wa Wong

C5 nerve root palsy after cervical laminoplasty and posterior fusion with instrumentation.

Study Design Consecutive case series. Objective To compare the incidence and clinical characteristics of postoperative fifth cervical nerve root palsy (C5 palsy) in patients with cervical myelopathy treated by laminoplasty alone and laminoplasty with posterior instrumentation. Summary of Background Data In patients who have multilevel cervical myelopathy with reducible kyphosis or instability, the authors have performed laminoplasty together with instrumented fusion to restore lordosis and stability. There seems to be a high incidence of postoperative C5 palsy in these patients. Methods Seventy-three patients with a mean age of 60.5 years and multilevel cervical myelopathy treated by laminoplasty from 1995 to 2005 were reviewed. Incidence, side, and severity of muscle weakness from patients with C5 palsy after posterior instrumented fusion (instrumented group) was compared with those without instrumentation (noninstrumented group). Radiologic parameters were assessed to identify predisposing factors. Results Overall 10 of 73 (14%) patients developed the C5 palsy, of which 5 (50%) of 10 patients were in instrumented group, and 5 of 63 (8%) patients were in noninstrumented. Three of 5 (60%) had the palsy on the same side of the opened lamina in the instrumented group, in the same proportion as the noninstrumented. Three (60%) patients in instrumented group developed deltoid weakness grade 1, but none in the noninstrumented had weaker than grade 3. All of the palsied in the instrumented group recovered within 2 years after surgery without removal of implant. Of the 5 patients with the palsy in the instrumented group, 3 had anterolisthesis before surgery and posterior translation of C4 on C5 by the surgery, and no patient without the palsy had the anterolisthesis. Conclusions Posterior cervical fusion using instrumentation for restoration of lordotic alignment combined with laminoplasty is highly associated with severe postoperative C5 palsy in patients with multilevel cervical myelopathy and C4 anterolisthesis.

Selection of fusion levels in adolescent idiopathic scoliosis using fulcrum bending prediction - a prospective study

Study Design. A prospective study of 50 consecutive patients undergoing selective thoracic fusion for idiopathic scoliosis with minimum 2 year follow-up. Objective. We aim to establish the validity and safety of a new strategy using fulcrum bending (FB) radiographs and the inherent flexibility of the curve to select fusion levels for King type 2 and 3 curves (Lenke 1a, 1b, and 1c). The purpose of this new strategy is to preserve motion segments compared to the traditional method of selecting fusion levels. Summary of Background Data. The aim of fusion in idiopathic scoliosis is to achieve a balanced spine with the shortest fusion preserving motion segments particularly in the lumbar spine. Conventional strategies for choosing fusion levels have been based on the standing radiographs and have not taken into account the flexibility of the curve. Methods. We followed 50 consecutive patients who underwent selective thoracic fusion for King 2 and 3 curves (Lenke 1a, 1b, and 1c). The fusion levels were chosen based on our new strategy using the FB radiograph. Twenty-five patients were fused using a hook system and 25 with a hybrid system of hooks and screws. All patients were observed until skeletal maturity and a minimum of 2 years. The curve correction, trunk shift, radiographic shoulder height, list were recorded at the preoperative stage, postoperative stage, and final follow-up. Results. The patients had an average age of 15.4 years. The average preoperative Cobb angle was 55.4° and final follow-up Cobb angle for the primary curve was 24.1°, with no difference between the 2 groups. With the new strategy, we were able to save levels in 31 patients (62%), compared to the conventional method of selecting the lowest instrumented vertebra. There was a statistically significant difference in the correction of the fusion mass Cobb angle between the hook and hybrid groups. There was significant improvement in the trunk shift after surgery. Ninety-six percent of patients had balanced or minimally imbalanced shoulders at final follow-up. Three patients had tilting of the vertebra below the fusion mass into the primary curve that did not progress at skeletal maturity. Conclusion. The new objective strategy for determining fusion levels using FB radiographs is safe and effective. With considering the flexibility of the curve, we are able to save levels distally in over 60% of patients. This strategy takes into account the power of modern instrumentation.

''Spring-back'' closure associated with open-door cervical laminoplasty

BACKGROUND CONTEXT Spring-back complication after open-door laminoplasty as described by Hirabayashi is a well-known risk, but its definition, incidence, and associated neurologic outcome remain unclear. OBJECTIVE To investigate the incidence and the neurologic consequence of spring-back closure after open-door laminoplasty. STUDY DESIGN A retrospective radiographic and clinical review. OUTCOME MEASURES Lateral cervical spine X-rays were evaluated. Anteroposterior diameters (APD) of the vertebral canal of C3-C7 were measured. Spring-back was defined as loss of APD on follow-up in comparison to immediate postoperative canal expansion. The loss of the end-on lamina silhouette with consequent reappearance of the lateral profile of the spinous processes was also assessed to verify the presence of spring-back. Spring-back closure was classified based on whether the collapse was total or partial, and whether all the operated levels or only a subset had collapsed (ie, complete vs. partial closure, segmental closure vs. total-construct closure). Neurologic status was documented using the Japanese Orthopaedic Association (JOA) score. METHODS Thirty consecutive patients who underwent open-door laminoplasty from 1995 to 2005 at a single institution with a minimum follow-up of 2 years were assessed. They were all operated on using the classic Hirabayashi technique. Radiographic outcomes were assessed independently by two individuals. RESULTS Sixteen men and 14 women with an average follow-up of 5 years (range, 2-12 years) were included. Of these patients, 24 had cervical spondylotic myelopathy and six had ossification of the posterior longitudinal ligament. Spring-back closure was found in three patients (10%) and 7 of 117 laminae (6%) within 6 months of the operation, which was further confirmed by computed tomography and magnetic resonance imaging. All spring-back closures were partial segmental closures. Gender and age were not significant factors related to spring back (p>.05). The mean JOA score on follow-up was 12.5, with a recovery rate of 40%. All patients with spring back and available JOA data exhibited postoperative neurologic deterioration. Of the three patients with spring back, two patients underwent revision surgery, whereas one declined. CONCLUSIONS Spring-back closure occurred in 10% of our patients at or before 6 months after surgery. The incidence of spring-back by level (ie, 117 laminae) was 6%, mainly occurring at the lower cervical spine. All spring-back closures were partial segmental closures, most commonly involving C5 and C6. Postoperative neurologic deficit was associated with spring-back closure; therefore, surgeons should adopt preemptive surgical measures to prevent the occurrence of such a complication.

A Multidisciplinary Rehabilitation Programme for Patients with Chronic Low Back Pain: A Prospective Study

Purpose. To examine the effectiveness of a multidisciplinary rehabilitation programme for patients with chronic low back pain in Hong Kong, and to identify factors associated with work resumption. Methods. 57 men and 8 women aged 20 to 56 (mean, 39) years who had a >3-month history of low back pain and were unresponsive to >6 months of conventional treatment participated in a 14-week multidisciplinary rehabilitation programme involving physical conditioning, work conditioning, and work readiness. Training protocols entailed flexibility and endurance training, hydrotherapy, weight lifting, and work stimulation. Patients were assessed at baseline (week 1), week 7, week 14, and month 6 with regard to the intensity of low back pain, self-perceived disability, range of lumbar motion, isoinertial performance of the trunk muscles, and depression level. Patient demographics that influenced work resumption were identified using a prediction model. Patients who did and did not return to work were compared. Results. Of the 54 patients who completed all follow-up assessments, 28 returned to work and 26 did not. The latter was significantly older (37 vs. 42 years, p=0.038) and absent from work longer (11 vs. 22 months, p=0.029) than the former. The rehabilitation programme helped patients regain physical function and the ability to work. Patients who returned to work showed greater improvement in self-perceived disability and physical function. Conclusion. This rehabilitation programme facilitated regain of physical functioning and the ability to return to work. The pre-programme employment status, duration of absence from work, and patient age were the most important predictors for work resumption.

Quality of life of traumatic spinal cord injured patients in Hong Kong.

OBJECTIVE To assess the health-related quality of life of patients with traumatic spinal cord injury living in Hong Kong. DESIGN A cross-sectional retrospective study. SUBJECTS Subjects with paraplegia following traumatic spinal cord injury were recruited from our department, which is one of the 3 main regional spinal cord injury rehabilitation centres in Hong Kong. A total of 120 potential participants were invited to join the study. The final study group comprised 58 patients (25 (43%) men and 33 (57%) women, 30 (50%) of whom were under 40 years of age). METHODS Health-related quality of life was assessed using the Hong Kong Chinese version of the World Health Organization Quality of Life Measure Abbreviated version (WHO-QOL-BREF(HK)). Results were summarized and compared with previous results from healthy and other disease populations in Hong Kong. RESULTS There was no significant difference in quality of life between men and women, or between different durations of spinal cord injury, different educational levels or different marital status (p > 0.05). However, a significant difference in quality of life was found in different age groups and between people with incomplete and complete paraplegia (p < 0.05). Compared with healthy and other disease populations, people with paraplegia had the lowest quality of life in Hong Kong (p < 0.001). CONCLUSION People with paraplegia in Hong Kong have a lower quality of life than the general Hong Kong population. More community support is required to meet the needs of these patients in the areas of transportation, medical care and social life, in particular.

Prognosis of spontaneous thoracic curve correction after the selective anterior fusion of thoracolumbar/lumbar (Lenke 5C) curves in idiopathic scoliosis

BACKGROUND CONTEXT Prognosis of minor lumbar curve correction after selective thoracic fusion in idiopathic scoliosis is well defined. However, the prognosis of minor thoracic curve after isolated anterior fusion of the major lumbar curve has not been well described. PURPOSE To define the prognosis of spontaneous thoracic curve correction after selective anterior fusion of the lumbar/thoracolumbar curve in idiopathic scoliosis. STUDY DESIGN A retrospective cohort study on the prognosis of the minor curve after selective anterior correction and fusion of the lumbar/thoracolumbar curve in idiopathic scoliosis. PATIENT SAMPLE Idiopathic lumbar scoliosis patients treated with anterior spinal fusion. OUTCOME MEASURES The Scoliosis Research Society 22 questionnaire was used as an outcome measure at the final follow-up. METHODS Twenty-eight patients were included in this study. Four patients were male, 24 patients were female, and average age at the time of surgery was 16 years. Mean follow-up was 48 months. According to the Lenke Classification, 22 patients were 5CN, 5 were 5C-, and 1 was 5C+. All operations were performed in the same institution. Standing long posterior-anterior and lateral radiographs were taken just before surgery, 1 week after surgery, and at final follow-up. RESULTS The mean preoperative Cobb angle of the lumbar (major) curve was 53° (standard deviation [SD]=8.6) and that of the thoracic (minor) curve was 38.4° (SD=6.24). The lumbar and thoracic curves were corrected to 10° (SD=7.6) and 25° (SD=8.3) postoperatively and measured 17° (SD=10.6) and 27° (SD=7.7), respectively, at the last follow-up. There was a significant difference between the preoperative and postoperative measurements of the minor curves (p<.05). However, there was no significant difference between the early postoperative and the final follow-up measurements (p>.05). Regarding the overall sagittal balance, there was no significant difference between preoperative, early, and late postoperative measurements (p>.05). CONCLUSIONS Selective anterior fusion of the major thoracolumbar/lumbar curve was an effective method for the treatment of Lenke Type 5C curves. Minor thoracic curves did not progress after selective fusion of thoracolumbar/lumbar curves in minimum 2-year follow-up.

A population-based cohort study of 394,401 children followed for 10 years exhibits sustained effectiveness of scoliosis screening

BACKGROUND CONTEXT The value of scoliosis screening has been recently shown in a multicenter randomized controlled trial. However, the long-term sustainability of the clinical effectiveness of scoliosis screening as a routine health service remains unknown. PURPOSE The aim of this study was to assess the sustainability of the clinical effectiveness of school scoliosis screening. STUDY DESIGN/SETTING A large population-based cohort study with a 10-year follow-up was conducted. PATIENT SAMPLE A total of 394,401 students who were in the fifth grade during the five academic years from 1995/1996 to 1999/2000 formed five consecutive annual cohorts. The students were eligible for the Hong Kong scoliosis screening program, with their screening history and medical records until their nineteenth birthdays being assessed. OUTCOME MEASURES The outcome measures considered in the study were development of adolescent idiopathic scoliosis by the 19 years of age and the Cobb angle. METHODS The clinical effectiveness of scoliosis screening was assessed by referral rate for radiographic diagnosis, sensitivity, specificity, and predictive values. RESULTS A total of 306,144 students (78%) participated in scoliosis screening, which used a two-tier system. The prevalence of curves of 20° or greater was 1.8% (95% confidence interval [CI], 1.7-1.8%), whereas the referral rate for radiography, the sensitivity, and the positive predictive value (PPV) for curves of 20° or greater were 4.1% (95% CI, 4.0-4.2%), 91% (95% CI, 90-92%), and 40% (95% CI, 39-41%), respectively. Across the five consecutive annual cohorts, the prevalence and sensitivity for curves of 20° or greater increased by 0.23% (95% CI, 0.21-0.25%; p<.001) and 0.76% (95% CI, 0.43-1.04%; p<.001) per year, respectively; however, the PPV was reduced by 1.71% (95% CI, 1.09-2.33%; p<.001) per year. CONCLUSIONS This report describes the first large population-based study with a long-term follow-up indicating that a scoliosis screening program can have sustained clinical effectiveness in identifying patients with adolescent idiopathic scoliosis needing clinical observation. As the prevalence of adolescent idiopathic scoliosis increases, scoliosis screening should be continued as a routine health service in schools or by general practitioners if there is no scoliosis screening policy.

Effect of stimulation parameters on intraoperative spinal cord evoked potential monitoring.

The purpose of this study was to investigate the effects of the stimulus parameters on spinal cord evoked potential (SCEP) and to recommend a practical epidural stimulation protocol for intraoperative spinal cord monitoring. This prospective study compared the latencies and amplitudes of SCEP obtained on epidural stimulation of 30 patients with scoliosis under anesthesia using different stimulus pulse duration and stimulation rates. SCEP was found to be undetectable with shorter stimulus duration (<0.05 ms). The SCEP latencies did not show any significant difference among different stimulation parameters. However, the SCEP amplitude showed significant changes with differing stimulus durations. The SCEP amplitudes were found to significantly decrease when the pulse durations become shorter than 0.2 ms. Stimulus parameters showed significant effects on SCEP amplitude but not latency. Stimulus rates in the range of 21 to 61 Hz are equivalent for quick and reliable detection of SCEP. Considering the short latency of SCEP, a pulse duration of 0.2 ms is recommended for SCEP using epidural stimulation.