Takahito Fujimori

Long-term results of cervical myelopathy due to ossification of the posterior longitudinal ligament with an occupying ratio of 60% or more.

Study Design. Retrospective study. Objective. We sought to determine the long-term outcomes of laminoplasty versus anterior decompression and fusion in the treatment of cervical myelopathy caused by ossification of the posterior longitudinal ligament (OPLL) and to ascertain what factors should be considered in selecting appropriate surgical procedure. Summary of Background Data. There are little data about long-term results of cervical myelopathy due to OPLL with an occupying ratio 60% or more. Methods. We retrospectively studied 27 patients having OPLL with an occupying ratio 60% or more and a follow-up period of at least 2 years. Clinical outcome was evaluated using Japanese Orthopaedic Association scores and recovery rates (≥75%, excellent; 50%–74%, good; 25%–50%, fair; and <25%, poor). Results. The mean age and the mean duration of follow-up were 57 years and 10.2 years. The mean Japanese Orthopaedic Association score was 9.3 before surgery and 12.4 at the final follow-up examination. There were 15 patients in the laminoplasty group (LAM group) and 12 patients in the anterior decompression and fusion group (ADF group). The ADF group had a significantly better recovery rate at final evaluation (53% vs. 30%; P = 0.04), a longer duration of surgery (314 vs. 128 min; P < 0.01), and greater blood loss (600 vs. 240 mL; P < 0.01) than did the LAM group. In the LAM group, 4 patients with excellent or good results had a significantly larger degree of cervical lordosis (30°vs. 10°; P = 0.002) than others. Conclusion. The ADF group had a significantly better recovery rate than the LAM group, although the degree of surgical invasiveness was high. ADF is generally recommended for OPLL with an occupying ratio 60% or more. Level of Evidence: 3

Preservation of Muscles Attached to the C2 and C7 Spinous Processes Rather Than Subaxial Deep Extensors Reduces Adverse Effects After Cervical Laminoplasty

Study Design. Prospective study. Objective. To examine whether preservation of subaxial deep extensor muscles plays any significant role in reducing axial neck pain and unfavorable radiologic changes after cervical laminoplasty in patients with cervical spondylotic myelopathy and to confirm the benefits of preserving muscles attached to the C2 and C7 spinous processes. Summary of Background Data. Axial neck pain and unfavorable radiologic changes after cervical laminoplasty have been reported to mostly result from detachment of cervical extensor muscles, particularly muscles attached to the C2 and C7 spinous processes. Other surgeons have reported that preservation of subaxial deep extensor muscles reduces these adverse effects after cervical laminoplasty. Methods. Subjects comprised 36 patients with cervical spondylotic myelopathy who underwent C3–C6 open-door laminoplasty and were followed up for >24 months. Of these, 18 consecutive patients underwent our modified laminoplasty (muscles-preserved group) and the remaining 18 consecutive patients underwent the conventional procedure (muscles-disrupted group). Both procedures preserved all muscles attached to the C2 and C7 spinous processes. Subaxial deep extensor muscles on the hinged side were also preserved in the muscles-preserved group. Radiologic and clinical data were prospectively collected. Results. Both groups achieved equal neurologic improvement. Frequencies of axial neck pain showed no significant differences between groups. This value did not vary according to the side of preservation of subaxial deep extensor muscles or the side of muscle disruption. Postoperative loss of lordosis and range of motion of the cervical spine also demonstrated no significant difference between groups. Conclusion. These results indicate that preservation of subaxial deep extensor muscles plays no significant role in reducing axial neck pain and unfavorable radiologic changes after cervical laminoplasty, supporting the hypothesis that these adverse effects after laminoplasty largely result from detachment of muscles attached to the C2 and C7 spinous processes.

Three-dimensional measurement of growth of ossification of the posterior longitudinal ligament

OBJECT Ossification of the posterior longitudinal ligament (OPLL) is a progressive disease that causes cervical myelopathy. Because 2D evaluation of ossification growth with plain lateral radiographs has limitations, the authors developed a unique technique to measure ossification progression and volume increase by using multidetector CT scanning. METHODS The authors used serial thin-slice volume data obtained by multidetector CT scanning in 5 patients. The mean patient age was 63 years, and the mean follow-up duration was 3.1 years. First, a 3D model of OPLL was semiautomatically segmented at a specific threshold. Then, a preoperative model of OPLL was superimposed on a postoperative model using voxel-based registration of the vertebral bodies. Progression and volume increase were measured using a digital viewer that was developed by the authors. Progression was visualized using a color-coded contour on the surface of the OPLL model. RESULTS All patients had progression of 0.5 mm or greater. The mean values concerning OPLL growth were as follows: maximum progression length, 4.7 mm; progression rate, 1.5 mm/year; volume increase, 1622 mm(3); volume expansion rate, 37%; and volume increase rate, 484 mm(3)/year. The accuracy of superimposition by voxel-based registration, defined as closeness to the true value, was less than 0.31 mm. For intraobserver reproducibility of the volume measurement, the mean intraclass correlation coefficient, root mean square error, and coefficient of variation were 0.987, 16.0 mm(3), and 1.7%, respectively. CONCLUSIONS Ossification of the posterior longitudinal ligament progresses even after surgery. Three-dimensional evaluation with the aid of CT scans is a useful and reliable method for assessing that growth.

Long fusion from sacrum to thoracic spine for adult spinal deformity with sagittal imbalance: upper versus lower thoracic spine as site of upper instrumented vertebra.

OBJECT Despite increasing numbers of patients with adult spinal deformity, it is unclear how to select the optimal upper instrumented vertebra (UIV) in long fusion surgery for these patients. The purpose of this study was to compare the use of vertebrae in the upper thoracic (UT) versus lower thoracic (LT) spine as the upper instrumented vertebra in long fusion surgery for adult spinal deformity. METHODS Patients who underwent fusion from the sacrum to the thoracic spine for adult spinal deformity with sagittal imbalance at a single medical center were studied. The patients with a sagittal vertical axis (SVA) ≥ 40 mm who had radiographs and completed the 12-item Short-Form Health Survey (SF-12) preoperatively and at final follow-up (≥ 2 years postoperatively) were included. RESULTS Eighty patients (mean age of 61.1 ± 10.9 years; 69 women and 11 men) met the inclusion criteria. There were 31 patients in the UT group and 49 patients in the LT group. The mean follow-up period was 3.6 ± 1.6 years. The physical component summary (PCS) score of the SF-12 significantly improved from the preoperative assessment to final follow-up in each group (UT, 34 to 41; LT, 29 to 37; p = 0.001). This improvement reached the minimum clinically important difference in both groups. There was no significant difference in PCS score improvement between the 2 groups (p = 0.8). The UT group had significantly greater preoperative lumbar lordosis (28° vs 18°, p = 0.03) and greater thoracic kyphosis (36° vs 18°, p = 0.001). After surgery, there was no significant difference in lumbar lordosis or thoracic kyphosis. The UT group had significantly greater postoperative cervicothoracic kyphosis (20° vs 11°, p = 0.009). The UT group tended to maintain a smaller positive SVA (51 vs 73 mm, p = 0.08) and smaller T-1 spinopelvic inclination (-2.6° vs 0.6°, p = 0.06). The LT group tended to have more proximal junctional kyphosis (PJK), although the difference did not reach statistical significance. Radiographic PJK was 32% in the UT group and 41% in the LT group (p = 0.4). Surgical PJK was 6.4% in the UT group and 10% in the LT group (p = 0.6). CONCLUSIONS Both the UT and LT groups demonstrated significant improvement in clinical and radiographic outcomes. A significant difference was not observed in improvement of clinical outcomes between the 2 groups.

Kinematics of the thoracic spine in trunk rotation: in vivo 3-dimensional analysis.

Study Design. In vivo 3-dimensional (3D) study of the thoracic spine. Objective. To demonstrate axial rotations (ARs) and coupled motions of the thoracic spine. Summary of Background Data. In vivo 3D kinematics of the thoracic spine in trunk rotation with intact thorax and soft tissues has not been well-known. There were no quantitative data of AR in the consecutive thoracic spinal segments. Patterns of coupled motion with AR have been controversial. Methods. Thirteen healthy volunteers underwent 3D computed tomography of the thoracic spine in 3 positions; neutral, right, and left maximum trunk rotation. Relative motions of vertebrae were calculated by automatically superimposing the vertebrae in a neutral position over images in rotational positions, using voxel-based registration. Motions were represented with 6 degrees of freedom by Euler angles and translations on the local coordinate system. Results. Mean (±SD) relative rotational angles of T1 with respect to L1 to 1 side were 24.9° ± 4.9° in maximum trunk rotation. AR of each thoracic segment with respect to the inferior adjacent vertebra to 1 side was 1.2° ± 0.8° at T1–T2, 1.6° ± 0.7° at T2–T3, 1.4° ± 0.9° at T3–T4, 1.6° ± 0.8° at T4–T5, 1.8° ± 0.7° at T5–T6, 1.9° ± 0.6° at T6–T7, 2.3° ± 0.7° at T7–T8, 2.5° ± 0.8° at T8–T9, 2.7° ± 0.6° at T9–T10, 2.6° ± 0.8° at T10–T11, 1.3° ± 0.7° at T11–T12, and 0.5° ± 0.4° at T12–L1. Significantly larger segmental AR was observed at the middle thoracic segments (T6–T11) than at the upper (T1–T6) and lower (T11–L1) segments. At the upper thoracic segments, coupled lateral bending with AR was observed in the same direction as AR. However, at the middle and lower thoracic segments, coupled lateral bending occurred both in the same and opposite directions. Conclusion. In vivo 3D ARs and coupled motions of the consecutive thoracic spinal segments in trunk rotation were investigated accurately for the first time.

Does Transforaminal Lumbar Interbody Fusion Have Advantages over Posterolateral Lumbar Fusion for Degenerative Spondylolisthesis

Study Design Retrospective cohort study. Objective To compare the clinical and radiographic outcomes of transforaminal lumbar interbody fusion (TLIF) and posterolateral lumbar fusion (PLF) in the treatment of degenerative spondylolisthesis. Methods This study compared 24 patients undergoing TLIF and 32 patients undergoing PLF with instrumentation. The clinical outcomes were assessed by visual analog scale (VAS) for low back pain and leg pain, physical component summary (PCS) of the 12-item Short-Form Health Survey, and the Oswestry Disability Index (ODI). Radiographic parameters included slippage of the vertebra, local disk lordosis, the anterior and posterior disk height, lumbar lordosis, and pelvic parameters. Results The improvement of VAS of leg pain was significantly greater in TLIF than in PLF unilaterally (3.4 versus 1.0; p = 0.02). The improvement of VAS of low back pain was significantly greater in TLIF than in PLF (3.8 versus 2.2; p = 0.02). However, there was no significant difference in improvement of ODI or PCS between TLIF and PLF. Reduction of slippage and the postoperative disk height was significantly greater in TLIF than in PLF. There was no significant difference in local disk lordosis, lumbar lordosis, or pelvic parameters. The fusion rate was 96% in TLIF and 84% in PLF (p = 0.3). There was no significant difference in fusion rate, estimated blood loss, adjacent segmental degeneration, or complication rate. Conclusions TLIF was superior to PLF in reduction of slippage and restoring disk height and might provide better improvement of leg pain. However, the health-related outcomes were not significantly different between the two procedures.

Prevalence, Concomitance, and Distribution of Ossification of the Spinal Ligaments: Results of Whole Spine CT Scans in 1500 Japanese Patients.

Study Design. Cross-sectional study. Objective. To investigate the prevalence, concomitance, and distribution of various types of ossification of the spinal ligaments in healthy subjects using computed tomography (CT). Summary of Background Data. CT has better diagnostic accuracy for ossification of the spinal ligaments compared to plain radiography. Currently there is no study that examines the prevalence of ossification of the spinal ligaments using whole spine CT scans. Methods. One thousand five hundred Japanese patients (888 men and 612 women) who underwent positron emission tomography and CT (PETCT) in a private health check center between 2006 and 2013 were included. This PETCT was performed on self-paying participants as a preventive cancer screen. Existence of ossification of the posterior longitudinal ligament (OPLL), ligamentum flavum (OLF), anterior longitudinal ligament (OALL), diffuse idiopathic skeletal hyperostosis (DISH), and nuchal ligament (ONL) was examined. Results. The prevalence of spinal ligament ossifications was found to be 6.3% in cervical OPLL (8.3% in men and 3.4% in women), 23% in ONL (33% in men and 8.8% in women), 1.6% in thoracic OPLL (1.4% in men and 2.0% in women), 12% in thoracic OLF (15% in men and 7.7% in women), 37% in thoracolumbar OALL (45% in men and 26% in women), and 12% in DISH (16% in men and 6.2% in women). Thirteen percent of patients with cervical OPLL had thoracic OPLL, 34% of cervical OPLL had thoracic OLF, 45% of cervical OPLL had ONL, and 36% of cervical OPLL had DISH. The most common level was C5 for cervical OPLL, T1/2 for thoracic OPLL, T11 for thoracic OLF, and T8/9 for OALL. Conclusion. Accurate prevalence of various types of ossification of the spinal ligaments evaluated by CT was revealed. High concomitance was observed in each classification of spinal ligament ossification. Level of Evidence: 3

Ossification of the posterior longitudinal ligament of the cervical spine in 3161 patients: a CT-based study.

Study Design. A cross-sectional study. Objective. To examine the prevalence of ossification of the posterior longitudinal ligament (OPLL) and ossification of the nuchal ligament (ONL) of the cervical spine in the San Francisco area. Summary of Background Data. The prevalence of OPLL and ONL is unknown in the non-Asian population. Methods. This computed tomography–based cross-sectional study assessed the prevalence of OPLL and ONL within the cervical spine of patients treated at a level 1 trauma center between 2009 and 2012. The prevalence of both OPLL and ONL was compared between racial groups. Results. Of the 3161 patients (mean age, 51.2 ± 21.6 yr; 66.1% male), there were 1593 Caucasians (50.4%), 624 Asians (19.7%), 472 Hispanics (14.9%), 326 African Americans (10.3%), 62 Native Americans (2.0%), and 84 Others (2.7%). The prevalence of cervical OPLL was 2.2% (95% confidence interval [CI]: 1.7–2.8). The adjusted prevalence was 1.3% in Caucasian Americans (95% CI: 0.7–2.3), 4.8% in Asian Americans (95% CI: 2.8–8.1), 1.9% in Hispanic Americans (95% CI: 0.9–4.0), 2.1% in African Americans (95% CI: 0.9–4.8), and 3.2% in Native Americans (95% CI: 0.8–12.3). The prevalence of OPLL in Asian Americans was significantly higher than that in Caucasian Americans (P = 0.005). ONL was detected in 346 patients and the prevalence was 10.9% (95% CI: 10.0–12.0). The adjusted prevalence of ONL was 7.3% in Caucasian Americans (95% CI: 5.8–9.3), 26.4% in Asian Americans (95% CI: 21.9–31.5), 7.4% in Hispanic Americans (95% CI: 5.2–10.5), 2.5% in African Americans (95% CI: 1.2–4.9), and 25.8% in Native Americans (95% CI: 16.5–37.5). ONL was significantly more common in Asian Americans than in Caucasian Americans, Hispanic Americans, and African Americans (P = 0.001). Conclusion. This study also demonstrated that OPLL and ONL were significantly more common in Asian Americans than in Caucasian Americans. Level of Evidence: 3

Patient satisfaction with surgery for cervical myelopathy due to ossification of the posterior longitudinal ligament

OBJECT Surgical results in cervical myelopathy caused by ossification of the posterior longitudinal ligament (OPLL) evaluated with a patient-based method have not yet been reported. The purpose of this study was to examine patient satisfaction with surgery for cervical myelopathy due to OPLL and to clarify factors related to satisfaction. METHODS Clinical data in 103 patients (74 male and 29 female) who underwent surgery for cervical OPLL were retrospectively reviewed. The average age at surgery was 57 years, and the average follow-up period was 9.3 years. Outcomes were assessed using an original satisfaction questionnaire, the conventional Japanese Orthopaedic Association (JOA) scoring system, the JOA Cervical Myelopathy Evaluation Questionnaire, the 36-Item Short Form Health Survey, and the hospital anxiety and depression scale. Spearman rank correlation coefficients for 5-scale patient satisfaction against outcome measures were calculated to test relationships between variables. All variables were compared between the satisfied (responses of very satisfied or satisfied) and dissatisfied (responses of dissatisfied or very dissatisfied) groups. Parameters exhibiting a significant Spearman rank correlation or difference between the groups were entered in a stepwise logistic regression analysis model, with satisfaction as the dependent variable. RESULTS Sixty-nine patients were included in the analysis. There was not a significant difference in clinical data between these 69 study patients and the other 34 patients. Fifty-five patients (80%) were satisfied with the results of the surgery, and 58 patients (84%) reported that their condition was improved by the surgery. All patients who reported being very improved were either very satisfied or satisfied with the results of surgery. Quality of life (QOL), physical function (PF), and role physical (RP) were significantly correlated with patient satisfaction. The dissatisfied group had significantly more severe pain; lower maximum conventional JOA scores; lower maximum recovery rates; worse lower-extremity function (LEF); reduced QOL; and lower PF, RP, and vitality scores. Stepwise logistic regression analysis showed that PF, QOL, LEF, and maximum recovery rate based on JOA score were correlated with satisfaction. CONCLUSIONS Eighty percent of patients were satisfied with the surgical results after treatment of cervical myelopathy due to OPLL. Surgery for cervical OPLL was effective, as evaluated by both doctor- and patient-based methods. Patient satisfaction was related to QOL, PF (especially LEF), and improvement.

Kinematics of the thoracic spine in trunk lateral bending: in vivo three-dimensional analysis

BACKGROUND CONTEXT In vivo three-dimensional kinematics of the thoracic spine in trunk lateral bending with an intact rib cage and soft tissues has not been well documented. There is no quantitative data in the literature for lateral bending in consecutive thoracic spinal segments, and there has not been consensus on the patterns of coupled motion with lateral bending. PURPOSE To demonstrate segmental ranges of motion (ROMs) in lateral bending and coupled motions of the thoracic spine. STUDY DESIGN In vivo three-dimensional biomechanics study of the thoracic spine. PATIENT SAMPLE Fifteen healthy male volunteers. OUTCOME MEASURES Computed analysis by using voxel-based registration. METHODS Participants underwent computed tomography of the thoracic spine in three supine positions: neutral, right maximum lateral bending, and left maximum lateral bending. The relative motions of vertebrae were calculated by automatically superimposing an image of vertebrae in a neutral position over images in bending positions, using voxel-based registration. Mean values of lateral bending were compared among the upper (T1-T2 to T3-T4), the middle-upper (T4-T5 to T6-T7), the middle-lower (T7-T8 to T9-T10), and the lower (T10-T11 to T12-L1) parts of the spine. RESULTS At lateral bending, the mean ROM (±standard deviation) of T1 with respect to L1 was 15.6°±6.3° for lateral bending and 6.2°±4.8° for coupled axial rotation in the same direction as lateral bending. The mean lateral bending of each spinal segment with respect to the inferior adjacent vertebra was 1.4°±1.3° at T1-T2, 1.3°±1.2° at T2-T3, 1.4°±1.3° at T3-T4, 0.9°±0.9° at T4-T5, 0.8°±1.0° at T5-T6, 1.1°±1.1° at T6-T7, 1.7°±1.2° at T7-T8, 1.3°±1.2° at T8-T9, 1.6°±0.7° at T9-T10, 1.8°±0.8° at T10-T11, 2.3°±1.0° at T11-T12, and 2.2°±0.8° at T12-L1. The smallest and the largest amounts of lateral bending were observed in the middle-upper and the lower parts, respectively. There was no significant difference in lateral bending between the upper and the middle-lower parts. Coupled axial rotation of each segment was generally observed in the same direction as lateral bending. However, high variability was found at the T2-T3 to T5-T6 segments. Coupled flexion was observed at the upper and middle parts, and coupled extension was observed at the lower part. CONCLUSIONS This study revealed in vivo three-dimensional motions of consecutive thoracic spinal segments in trunk lateral bending. The thoracolumbar segments significantly contributed to lateral bending. Coupled axial rotation generally occurred in the same direction with lateral bending. However, more variability was observed in the direction of coupled axial rotation at T2-T3 to T5-T6 segments in the supine position. These results are useful for understanding normal kinematics of the thoracic spine.