Yutaka Nohara

Surgical results and related factors for ossification of posterior longitudinal ligament of the thoracic spine: A multi-institutional retrospective study

Study Design. Retrospective multi-institutional study Objective. To describe the surgical outcomes in patients with ossification of the posterior longitudinal ligament in the thoracic spine (T-OPLL) and to clarify factors related to the surgical outcomes. Summary of Background Data. Detailed analyses of surgical outcomes of T-OPLL have been difficult because of the rarity of this disease. Methods. The subjects were 154 patients with T-OPLL who were surgically treated at 34 institutions between 1998 and 2002. The surgical procedures were laminectomy in 36, laminoplasty in 51, anterior decompression via anterior approach in 25 and via posterior approach in 29, combined anterior and posterior fusion in 8, and sternum splitting approach in 5 patients. Instrumentation was conducted in 52 patients. Assessments were made on (1) The Japanese Orthopedic Association (JOA) scores (full score, 11 points), its recovery rates, (2) factors related to surgical results, and (3) complications and their consequences. Results. (1) The mean JOA score before surgery was 4.6 ± 2.0 and, 7.1 ± 2.5 after surgery. The mean recovery rate was 36.8% ± 47.4%. (2) The recovery rate was 50% or higher in 72 patients (46.8%). Factors significantly related to this were location of the maximum ossification (T1–T4) (odds ratio, 2.43–4.17) and the use of instrumentation (odds ratio, 3.37). (3) The frequent complications were deterioration of myelopathy immediately after surgery in 18 (11.7%) and dural injury in 34 (22.1%) patients. Conclusion. The factors significantly associated with favorable surgical results were maximum ossification located at the upper thoracic spine and use of instrumentation. T-OPLL at the nonkyphotic upper thoracic spine can be treated by laminoplasty that is relatively a safe surgical procedure for neural elements. The use of instrumentation allows correction of kyphosis or prevention of progression of kyphosis, thereby, enhancing and maintaining decompression effect, and its use should be considered with posterior decompression.

Different scapular kinematics in healthy subjects during arm elevation and lowering: Glenohumeral and scapulothoracic patterns

HYPOTHESIS The scapulothoracic (ST) joint affects glenohumeral (GH) joint function. We observed 3-dimensional scapular motions during arm elevation and lowering to identify the scapulohumeral rhythm in healthy subjects and to compare it between the dominant and nondominant arms. MATERIALS AND METHODS Twenty-one healthy subjects participated in this study. Participants randomly elevated and lowered the arms in the scapular plane, and data were recorded by a computerized 3-dimensional motion analyzer at each 10 degrees increment. RESULTS Of the 42 shoulders, 21 showed a greater ratio of GH motion relative to ST motion whereas the other 21 showed a smaller ratio of GH motion relative to ST motion. The angle of upward rotation of the scapula showed a statistically significant difference between both types. The mean maximum angles of upward rotation, posterior tilting, and internal rotation were 36.2 degrees +/- 7.0 degrees , 38.7 degrees +/- 5.7 degrees , and 36.8 degrees +/- 12.2 degrees , respectively. No significant difference was found in angles of 3 scapular rotations between the dominant and nondominant arms. DISCUSSION These results indicate that there are 2 distinctly different scapulohumeral rhythms in healthy subjects but without a significant difference between dominant and nondominant arms. These findings should be referred to when one is interpreting kinematics in a variety of shoulder disorders.

Distraction Rod Instrumentation with Posterolateral Fusion in Isthmic Spondylolisthesis: 53 Cases Followed for 18???89 Months

Fifty-three cases of isthmic spondylolisthesis were treated with distraction rod instrumentation and posterolateral fusion with or without nerve root decompression, and they were followed for an average of 39 months. Thirty-one cases without neurologic deficit were treated with instrumentation and fusion only. In 22 cases of predominant sciatic pain with neurologic deficit signs, nerve root decompression and instrumentation with fusion were conducted. The results showed a 90.6% solid union rate with satisfactory clinical improvement. Realignment of the vertebral displacement such as reduction of olisthesis and widening of the olisthetic disc spaces was obtained to some extent. No serious complications were encountered.

Outcomes of fusion surgery for ossification of the posterior longitudinal ligament of the thoracic spine: a multicenter retrospective survey: clinical article.

OBJECT The aim of this study was to evaluate the outcomes of fusion surgery in patients with ossification of the posterior longitudinal ligament in the thoracic spine (T-OPLL) and to identify factors significantly related to surgical outcomes. METHODS The study included 76 patients (34 men and 42 women with a mean age of 56.3 years) who underwent fusion surgery for T-OPLL at 7 spine centers during the 5-year period from 2003 to 2007. The authors evaluated the patient demographic data, underlying disease, preoperative comorbidities, history of spinal surgery, radiological findings, surgical methods, surgical outcomes, and complications. Surgical outcomes were assessed using the Japanese Orthopaedic Association (JOA) scale score for thoracic myelopathy (11 points) and the recovery rate. RESULTS The mean JOA scale score was 4.6 ± 2.1 points preoperatively and 7.7 ± 2.5 points at the time of the final follow-up examination, yielding a mean recovery rate of 45.4% ± 39.1%. The recovery rates by surgical method were 38.5% ± 37.8% for posterior decompression and fusion, 65.0% ± 35.6% for anterior decompression and fusion via an anterior approach, 28.8% ± 41.2% for anterior decompression via a posterior approach, and 57.5% ± 41.1% for circumferential decompression and fusion. The recovery rate was significantly higher in patients without diabetes mellitus (DM) than in those with DM. One or more complications were experienced by 31 patients (40.8%), including 20 patients with postoperative neurological deterioration, 7 with dural tears, 5 with epidural hematomas, 4 with respiratory complications, and 10 with other complications. CONCLUSIONS The outcomes of fusion surgery for T-OPLL were favorable. The absence of DM correlated with better outcomes. However, a high rate of complications was associated with the fusion surgery.

Acute Cervical Spinal Cord Injury Complicated by Preexisting Ossification of the Posterior Longitudinal Ligament : A Multicenter Study

Study Design. Retrospective multicenter study. Objective. To review the clinical characteristics of traumatic cervical spinal cord injury (SCI) associated with ossification of the posterior longitudinal ligament (OPLL). Summary of Background Data. Despite its potentially devastating consequences, there is a lack of information about acute cervical SCI complicated by OPLL. Methods. This study included consecutive patients with acute traumatic cervical SCI (Frankel A, B, and C) who were admitted within 48 hours of injury to 34 spine institutions across Japan. For analysis of neurologic outcome, patients who had completed at least a 6-month follow-up were included. Neurologic improvement was defined as at least one grade conversion in Frankel grade. Results. A total of 453 patients were identified (367 men, 86 women; mean age, 59 years). OPLL was found in 106 (23%) patients (87 men, 19 women; mean age, 66 years). Most of the patients with OPLL (94 of 106) were without bone injury, presenting with incomplete SCI. The prevalence of OPLL reached 34% in SCI without bone injury. The cause of SCI was predominantly falls (74%). Only 25% of the patients were aware of OPLL. Half of the OPLL patients reported gait disturbance before injury. Forty-eight (52%) OPLL patients without bone injury underwent surgery (median, 13.5 days after injury), mostly laminoplasty. Overall, no significant difference was noted in neurologic improvement between surgery group and conservative group. However, further stratification showed that surgery was associated with greater neurologic recovery in patients who had gait disturbance before injury (P = 0.04). Conclusion. Prevalence of OPLL among cervical SCI was alarmingly high, especially in those without bone injury. Most of cervical SCI associated with OPLL were incomplete, without bone injury, and caused predominantly by low-energy trauma. The majority of the patients were unaware of OPLL. Surgery produced better neurologic recovery in patients who had gait disturbance before injury.

Discriminative validity and responsiveness of the Oswestry Disability Index among Japanese outpatients with lumbar conditions

The Oswestry Disability Index (ODI) is one of the most used assessment scales for patients with spine conditions, and translations into several languages have already been available. However, the scale’s discriminative validity and responsiveness to the clinical change was somewhat understudied in these translated versions of the ODI. In this study, we independently developed a Japanese version of the ODI, and tested its discriminative and responsive performances among outpatients with various spinal conditions. We recruited 167 outpatients from seven participating clinics, and concurrently measured the translated ODI and MOS Short Form 36 (SF36) as a reference scale. We also obtained from medical records clinical information such as diagnoses, the past history of surgery, and existence of subjective symptoms and clinical signs. For testing discriminative validity, scores were compared by the number of symptoms and signs, with the trend test. Receiver operating characteristics (ROC) analysis was also conducted to compare ODI and SF36 in their performance to discriminate the existence of signs/symptoms, by chi-square test on the area under ROC curve (AUC). For 35 patients (17 clinically stable, 18 undergoing surgery and clinically significantly changed), the two scales were repeatedly administered after 3–6 months to compare responsiveness by using ROC analysis. The translated ODI and the SF36 Physical Function (PF) subscale showed a significant trend increase as the numbers of symptoms/signs increased. They also showed comparable performance in discriminating the existence of signs/symptoms (AUC=0.70–0.76 for ODI, 0.69–0.70 for SF36 PF, P=0.15–0.81), and clinical status change over time (AUC=0.82 for ODI, 0.72 for SF36 PF, P=0.31). Our results showed that the translated Japanese ODI showed fair discriminative validity and responsiveness as the original English scale showed.

Action of chondroitinase ABC on epidurally transplanted nucleus pulposus in the rabbit.

STUDY DESIGN After autotransplanting the nucleus pulposus into the epidural space of rabbits, chondroitinase ABC was administered, and the effect of chondroitinase ABC was examined. OBJECTIVES To examine whether chondroitinase ABC accelerates resolution of the nucleus pulposus transplanted into the epidural space. SUMMARY OF BACKGROUND DATA No previous reports exist on the effect of chondroitinase ABC on the nucleus pulposus in the epidural space. METHODS In Study 1, autotransplantation of the nucleus pulposus into the epidural space was performed in rabbits. Histologic change was observed. In Study 2, dry weight, deoxyribonucleic acid content, and the amount of glycosaminoglycans of autotransplanted nucleus pulposus were quantified and compared with the respective values in the control group, chondroitinase-ABC-injected group, and phosphate-buffered saline-injected group. In Study 3, granulocytes obtained from the blood of a rabbit treated with chondroitinase ABC or phosphate-buffered saline were added to the nucleus pulposus taken from the same rabbit. RESULTS In chondroitinase ABC group, inflammatory cells tended to infiltrate earlier than those in the control group (Study 1). The dry weight of recollected nucleus pulposus in the chondroitinase ABC group was significantly less than in the other groups. Deoxyribonucleic acid content in the nucleus pulposus tended to be larger in the chondroitinase ABC group, although no significant difference in content compared with that in the other groups was found. Regarding the residual glycosaminoglycans in the transplanted nucleus pulposus, the amount of chondroitin sulfate markedly decreased in the chondroitinase ABC group (Study 2). The number of granulocytes infiltrating the nucleus pulposus was distinctly large in the chondroitinase ABC group (Study 3). CONCLUSION Chondroitinase ABC can enhance resolution of the nucleus pulposus in the epidural space.

Epidemiological aspects of scoliosis in a cohort of Japanese patients with Prader-Willi syndrome

BACKGROUND CONTEXT The prevalence of scoliosis in Prader-Willi syndrome (PWS) is high; however, the prevalence of PWS is rare, with one person in 10,000 to 20,000 affected. The etiology and characteristics of scoliosis associated with PWS remain unidentified. In addition, it is believed that the speedup of growth associated with growth hormone (GH) supplement treatment may influence the deterioration of scoliosis in PWS. PURPOSE To investigate scoliosis in Japanese patients with PWS. STUDY DESIGN Retrospective observational study. PATIENT SAMPLE We investigated 101 patients (67 men, 34 women) who were followed up from November 2002 to January 2008. All patients were diagnosed using fluorescence in situ hybridization or the methylation test. Of the 101 patients, 80 had an inherited deletion of chromosome 15q11-13 (deletion) and 21 patients had no deletion, including those with uniparental disomy. OUTCOME MEASURES 1) Prevalence of scoliosis; 2) association of scoliosis with GH treatments; 3) association of scoliosis with genotype; 4) clarification of PWS scoliosis characteristics; and 5) analysis of severe PWS scoliosis patients (Cobb angle greater than 40 degrees ). Scoliosis for our study was defined as scoliosis with a Cobb angle greater than 10 degrees . METHODS To investigate PWS-associated scoliosis, we used spinal X-ray examinations. The pattern of scoliosis was classified into three types: primary single lumbar or thoracolumbar curve (Type 1), double curve (Type 2), and primary single thoracic curve (Type 3). For statistical analysis, chi-square tests for the distribution of patients were used (p<.05). RESULTS 1) Scoliosis was found in 38.6% (39/101) of patients with PWS. 2) There was no statistical difference in the prevalence of scoliosis between the GH treatment group (32.8%) and the GH nontreatment group (group with no GH treatments) (46.5%) (p=.16, chi-square test). 3) There was no statistical difference in the prevalence of scoliosis between the deletion group (38.8%) and the nondeletion group (38.1%) (p=.84, chi-square test). 4) Scoliosis was classified into three types, according to single or double curve scoliosis and position of scoliosis. The prevalence of these groups was 61.5% for Type 1 (primary single lumbar and thoracolumbar curve), 48.7% for lumbar curve convex on the left side, 28.2% for Type 2 (double curve), and 10.3% for Type 3 (primary single thoracic curve). 5) Severe scoliosis was found in nine patients (8.9%, 9/101). Type 2 was found in 66.7% (6/9) of patients with severe scoliosis. During the follow-up period, two patients changed from Type 1 to Type 2. CONCLUSIONS Scoliosis in PWS can be classified into three types. A lumbar curve convex on the left side was found in most patients. In addition, severe deterioration of scoliosis was found in Type 2 patients. Therefore we recommend careful, ongoing observations for patients showing double curve tendencies.

Stability of volar locking plate systems for AO type C3 fractures of the distal radius: biomechanical study in a cadaveric model

BackgroundThe purpose of the present study was to compare the relative stability of five volar locking plates (all of which are available for the treatment of intraarticular fractures of the distal radius) under loading conditions simulating the physiological forces that occur during early active mobilization.MethodsFive plating techniques were applied to surgically simulated AO type C3.2 distal radius fractures in formalin-fixed cadavers. The specimens were tested with a servohydraulic materials testing machine with 250 N of axial compression load for 3000 cycles. After cyclic loading, the specimens were loaded until they demonstrated failure in axial compression. The five fixation systems studied included a DRV locking plate (group 1), a Stellar plate (group 2), an Acu-Loc plate (group 3), AO Locking Distal Radius System 2.4 (group 4); and a Matrix SmartLock plate (group 5).ResultsNone of the plate fixations tested failed during the cyclic loading. Group 2 had a higher elastic limit than groups 4 and 5. There were no significant differences among the five groups for the failure load. Failure occurred at the distal portion of the fixation system, at the ulnar side locking pin, or the locking screw was bent (groups 1, 2, 3); the ulnar side locking screw was broken (groups 3, 4); the locking screw became loose (group 4); and the ulnar side locking screw was uncoupled from the screw hole (group 5).ConclusionsAll of the five volar plate fixation systems provided sufficient stability to permit 3000 repeated motions of the digits after surgery for AO type C3 distal radius fractures.

Minimum 20 Years Long-term Clinical Outcome After Spinal Fusion and Instrumentation for Scoliosis: Comparison of the SRS-22 Patient Questionnaire With That in Nonscoliosis Group.

Study Design. A retrospective minimum 20-year follow-up study using 4 standard self-administered questionnaires, one of which, the SRS-22 was also administered to control groups. Objective. To evaluate long-term postoperative pain and other clinical outcomes of scoliosis correction and fusion surgery with Harrington instrumentation using Moe square-ended rods for better preservation of sagittal alignment. Summary of Background Data. Only a few long-term outcome studies have used standardized and validated self-administered tools, and no studies have established SRS-22 control data within their own population. There is no previous minimum 20-year follow-up evaluation after correction surgery preserving thoracic kyphosis and lumbar lordosis. Methods. Of 86 consecutive patients who underwent instrumentation surgery for scoliosis by a single surgeon, 61 patients participated using Japanese Orthopaedic Association, Roland-Morris Disability Questionnaire, Oswestry Disability Index, and Scoliosis Research Society (SRS-22) questionnaires and 51 patients were included in this study. Results were analyzed for pain and other clinical outcomes. A total of 771 hospital employees were sent SRS-22 questionnaires. A total of 763 responded, resulting in 2 control groups composed of nonscoliosis and untreated mild scoliosis controls of the same culture and language as the long-term follow-up group. Results. The prevalence of continuous low back pain was about 15%. Average Japanese Orthopaedic Association, Oswestry Disability Index, and Roland-Morris Disability Questionnaire scores at follow-up were 25 points, 7.3%, and 1.6, respectively. The average SRS-22 scores were 4.2 (function), 4.3 (pain), 3.7 (self-image), and 3.9 (mental health) for the postoperative follow-up group compared with 4.5 (function), 4.3 (pain), 3.5 (self-image), and 3.5 (mental health) for the nonscoliosis controls. Conclusion. Improved preservation of normal sagittal alignment resulted in a prevalence of low back pain comparable with the age-matched general population. Moreover, SRS-22 results for self-image and mental health were positive compared with the controls, possibly reflecting the surgeons emphases on mental health and management of patient expectations. Level of Evidence: 4