Shota Takenaka

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

Effect of Biological Agents on Cervical Spine Lesions in Rheumatoid Arthritis

Study Design. A retrospective cohort analysis. Objective. To determine the effect of biological agents (BAs) on the development and progression of cervical spine lesions and identify predictors of lesion progression. Summary of Background Data. The introduction of BAs has facilitated advances in the treatment of rheumatoid arthritis (RA). BAs reduce disease activity and limit structural joint damage. However, the effect of BAs on cervical spine lesions remains unclear. Methods. Thirty-eight subjects who received more than 2 years of continuous BA treatment were enrolled. The mean x-ray interval was 4.4 years. RA activity was evaluated by disease activity score (DAS)-C reactive protein (CRP) and matrix metalloproteinase (MMP)-3. Radiographical definitions of cervical lesions were atlanto-dental interval (ADI) more than 3 mm for atlanto-axial subluxation (AAS), Ranawat value less than 13 mm for vertical subluxation (VS), and anterior or posterior listhesis more than 2 mm for subaxial subluxation (SS). Definitions of radiographical progression were an increase of ADI more than 2 mm for AAS, a decrease of both Ranawat and Redlund-Johnell values more than 2 mm for VS, and an increase of listhesis more than 2 mm for SS. Results. RA activity responded dramatically to BA therapy (DAS-CRP from 4.3 to 2.3, P < 0.01; MMP-3 from 207.9 ng/mL to 105.6 ng/mL, P < 0.01). Baseline radiographical evaluation showed no pre-existing cervical spine lesions in 12 cases, AAS in 15 cases, and VS in 11 cases. Radiological progression was found in 1 (8%) patient in the no lesion group, 12 patients (80%) in the AAS group, and 9 patients (80%) in the VS group. The incidence of progression was significantly lower in the no lesion group compared with the other groups. Multivariate regression analysis showed that the presence of pre-existing cervical lesions was the single greatest predictor of progression. Conclusion. BAs prevented the development of de novo cervical spine lesions in patients with RA, but failed to inhibit progression of pre-existing RA lesions.

The use of cooled saline during bone drilling to reduce the incidence of upper-limb palsy after cervical laminoplasty: clinical article.

OBJECT No previous hypothesis has attempted to fully account for the occurrence of upper-limb palsy (ULP) after cervical laminoplasty. The authors propose that friction-generated heat from a high-speed drill may cause thermal injury to the nerve roots close to the drilled bone, which may then lead to ULP. The authors investigated the effect of cooling the saline used for irrigation during the drilling on the incidence of upper-limb (C-5) palsy following cervical laminoplasty. METHODS The irrigation saline for drilling was used at room temperature (RT, average temperature of 25.6°C) in operations of 79 patients (the RT group) and cooled to an average of 12.1°C in operations of 80 patients (the low-temperature [LT] group). The authors used a hand-held dynamometer to precisely assess muscle strength presurgery and 2 weeks postsurgery. RESULTS There was a 7.6% and 1.9% decrease in the strength of the deltoid muscle, a 10.1% and 4.4% decrease in the strength of the biceps brachii, a 1.3% and 0.6% decrease in the strength of the triceps brachii, and a 7.6% and 3.1% decrease in grip strength in the RT and LT groups, respectively. Multivariate analysis revealed that a significant predictor for decreased deltoid muscle strength was the use of irrigation saline at RT. CONCLUSIONS Using cooled irrigation saline during bone drilling significantly decreased the incidence of ULP and can thus be recommended as a simple method for the prevention of ULP.

Thoracic spinal epidural angiolipoma: report of two cases and review of the literature.

AIM Spinal angiolipoma is a benign uncommon neoplasm composed of mature lipocytes admixed with abnormal blood vessels, and accounts for only 0.14-1.2% of all spinal tumors. MATERIAL AND METHODS Retrospective data analysis. RESULTS We report two cases of a 64-year-old woman and a 65-year-old man with thoracic myelopathy due to spinal angiolipoma. Magnetic resonance imaging showed isointensity on T1-weighted imaging and hyperintensity on T2-weighted imaging and enhance with gadolinium administration. In one case, angiography elucidated the vascularity of the tumor and the relationship with concomitant hemangioma. Laminoplasty was performed to achieve tumor resection, and the postoperative course was uneventful with neurological improvement. Histopathological examination of the resected tumors revealed angiolipomas. CONCLUSION Although extremely rare, thoracic spinal epidural angiolipoma should be considered in the differential diagnosis of thoracic spinal lesions. Prognosis after surgical management of this lesion is favorable. Angiography was useful for preoperative evaluation of vascularity and the relationship with concomitant tumors.

Postoperative 24-hour result of 15-second grip-and-release test correlates with surgical outcome of cervical compression myelopathy.

Study Design. A prospective follow-up study to detect the early neurological improvement after decompression surgery and to clarify its correlation with the late neurological outcome in patients with cervical compression myelopathy. Objective. To reveal the suitability of a simple performance, 15-second grip-and-release test for postoperative neurological recovery in patients with cervical myelopathy. Summary of Background Data. Although various parameters have been advocated as prognostic factors, there still remain arguments against them. Furthermore, neurological status after decompression surgery has been evaluated weekly or monthly in previous studies, but not hourly or daily. To follow the postoperative neurological recovery, we used our original performance test. Methods. Forty-eight patients who were admitted to undergo decompressive laminoplasty for cervical myelopathy were enrolled in the study. Twenty-five patients who were admitted for lumbar spine surgery were used as controls. Subjects were asked to fully grip and release with their right (or left) hand fingers as fast as possible for 15 seconds, which was recorded by a digital camera. And the number of grip-and-release cycles was counted (15-second test) in the recorded video files. Results. In the myelopathy group, the number of grip-and-release cycles before surgery and 4 hours, 24 hours, 48 hours, 1 week, and 2 weeks after surgery was 26.7 ± 10.0, 29.7 ± 9.9, 35.0 ± 11.3, 35.1 ± 9.8, 36.2 ± 9.6, and 37.2 ± 10.2, respectively. The number increased steeply after surgery until 24 hours, and the number was 94% after 24 hours of the number recorded 2 weeks after surgery. In the control group, the number of grip-and-release cycles at each time point was 37.9 ± 9.7, 34.7 ± 9.1, 39.2 ± 9.0, 38.5 ± 8.9, 38.9 ± 9.7, and 38.0 ± 9.3, respectively. There was a transient reduction 4 hours after surgery. Conclusion. Because the number recorded 24 hours after surgery was significantly correlated with both the maximum gain in the number on the 15-second test and the gain in the Japan Orthopaedic Association score, it could be used as a prognostic factor for neurological outcome in patients with cervical myelopathy.

Surgical outcomes of temporary short-segment instrumentation without augmentation for thoracolumbar burst fractures

BACKGROUND Short-segment posterior spinal instrumentation for thoracolumbar burst fracture provides superior correction of kyphosis by an indirect reduction technique, but it has a high failure rate. We investigated the clinical and radiological results of temporary short-segment pedicle screw fixation without augmentation performed for thoracolumbar burst fractures with the goal of avoiding treatment failure by waiting to see if anterior reconstruction was necessary. METHODS We studied 27 consecutive patients with thoracolumbar burst fracture who underwent short-segment posterior instrumentation using ligamentotaxis with Schanz screws and without augmentation. Implants were removed approximately 1 year after surgery. Neurological function, kyphotic deformity, canal compromise, fracture severity, and back pain were evaluated prospectively. RESULTS After surgery, all patients with neurological deficit had improvement equivalent to at least 1 grade on the American Spinal Injury Association impairment scale and had fracture union. Kyphotic deformity was reduced significantly, and maintenance of the reduced vertebra was successful even without vertebroplasty, regardless of load-sharing classification. Therefore, no patients required additional anterior reconstruction. Postoperative correction loss occurred because of disc degeneration, especially after implant removal. Ten patients had increasing back pain, and there are some correlations between the progression of kyphosis and back pain aggravation. CONCLUSION Temporary short-segment fixation without augmentation yielded satisfactory results in reduction and maintenance of fractured vertebrae, and maintenance was independent of load-sharing classification. Kyphotic change was caused by loss of disc height mostly after implant removal. Such change might have been inevitable because adjacent endplates can be injured during the original spinal trauma. Kyphotic change after implant removal may thus be a limitation of this surgical procedure.

Surgical outcomes for painless drop foot due to degenerative lumbar disorders.

Study Design: Twenty patients presenting with painless drop foot who had undergone lumbar spine surgery for degenerative lumbar diseases were included in this retrospective study. Objective: This study aims to investigate which causative factors and patient symptoms significantly affected surgical outcome. Summary of Background Data: Drop foot is a neuromuscular condition that results in dorsiflexion palsy of the ankle. Patients with drop foot often complain of leg pain. Rarely, patients experience painless drop foot due to lumbar degenerative disease. For these patients, the only purpose of surgery is to improve the palsy; this makes it difficult to determine whether surgical intervention is indicated. No studies have focused on the results of surgical treatment for painless drop foot caused by degenerative lumbar diseases. Methods: Preoperative strength of the tibialis anterior and duration of palsy were recorded and considered with surgical outcome. Results: Sixty-five percent of patients recovered from drop foot after surgery. Drop foot was caused mainly by impairment of the L5 nerve root. Patients with a longer duration of palsy had poorer results. Conclusions: Duration of palsy had the greatest effect on recovery. As the only goal of this surgery is improvement in the strength of the tibialis anterior, caution must be exercised when considering surgery for patients with longstanding palsy.

Risk factors for poor patient-reported quality of life outcomes after posterior lumbar interbody fusion: An analysis of two-year follow-up.

Study Design. A retrospective review of prospectively collected data. Objective. The present study aimed to identify risk factors for poor patient-reported quality of life (QOL) outcomes, based on five categories (pain-related disorders, lumbar spine dysfunction, gait disturbance, social life dysfunction, and psychological disorders) of the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ), after posterior lumbar interbody fusion (PLIF) at the 2-year follow-up. Summary of Background Data. Many studies have been reported on patient QOL outcomes after lumbar surgery; however, few reports have focused on risk factors for poor postoperative QOL outcomes in terms of the various disabilities and dysfunctions after PLIF. Methods. One hundred consecutive patients (39 men and 61 women; mean age 69.6 [44–84] yr) who underwent single- or two-level PLIF for degenerative spondylolisthesis and/or foraminal stenosis with a 2-year follow-up were included. The effectiveness of surgery in each category of the JOABPEQ was evaluated. Demographic and clinical data and radiographic parameters were reviewed. Risk factors for poor postoperative QOL outcomes in each category of the JOABPEQ were investigated by multivariate logistic regression analysis. Results. Older age and spinopelvic malalignment (preoperative high pelvic tilt or postoperative decrease in lumbar lordosis [=postoperative increase in the mismatch between pelvic incidence and lumbar lordosis]) were risk factors for poor postoperative QOL outcomes in all categories of the JOABPEQ, except for lumbar spine dysfunction. In contrast, increase in number of PLIF segments, non-union, and radiographic adjacent segment degeneration were risk factors for poor postoperative QOL outcomes in lumbar spine dysfunction and gait disturbance. Conclusion. The risk factors for poor QOL outcomes after PLIF differed among the five categories of the JOABPEQ. In particular, surgery-related factors (e.g., increase in number of PLIF segments, nonunion, and radiographic adjacent segment degeneration) had a negative effect on the improvement of lumbar spine dysfunction and gait disturbance. Level of Evidence: 4

Preoperative retrolisthesis as a risk factor of postdecompression lumbar disc herniation.

OBJECT In this study, the authors aimed to identify specific risk factors for postdecompression lumbar disc herniation (PDLDH) in patients who have not undergone discectomy and/or fusion. METHODS Between 2007 and 2012, 493 patients with lumbar spinal stenosis underwent bilateral partial laminectomy without discectomy and/or fusion in a single hospital. Eighteen patients (herniation group [H group]: 15 men, 3 women; mean age 65.1 years) developed acute sciatica as a result of PDLDH within 2 years after surgery. Ninety patients who did not develop postoperative acute sciatica were selected as a control group (C group: 75 men, 15 women; mean age 65.4 years). Patients in the C group were age and sex matched with those in the H group. The patients in the groups were also matched for decompression level, number of decompression levels, and surgery date. The radiographic variables measured included percentage of slippage, intervertebral angle, range of motion, lumbar lordosis, disc height, facet angle, extent of facet removal, facet degeneration, disc degeneration, and vertebral endplate degeneration. The threshold for PDLDH risk factors was evaluated using a continuous numerical variable and receiver operating characteristic curve analysis. The area under the curve was used to determine the diagnostic performance, and values greater than 0.75 were considered to represent good performance. RESULTS Multivariate analysis revealed that preoperative retrolisthesis during extension was the sole significant independent risk factor for PDLDH. The area under the curve for preoperative retrolisthesis during extension was 0.849; the cutoff value was estimated to be a retrolisthesis of 7.2% during extension. CONCLUSIONS The authors observed that bilateral partial laminectomy, performed along with the removal of the posterior support ligament, may not be suitable for lumbar spinal stenosis patients with preoperative retrolisthesis greater than 7.2% during extension.

BMP-2/7 heterodimer strongly induces bone regeneration in the absence of increased soft tissue inflammation

BACKGROUND CONTEXT Bone morphogenetic protein (BMP)-2/7 heterodimer is a stronger inducer of bone regeneration than individual homodimers. However, clinical application of its potent bone induction ability may be hampered if its use is accompanied by excessive inflammatory reactions. PURPOSE We sought to quantitatively evaluate bone induction and inflammatory reactions by BMP heterodimer and corresponding BMP homodimers using ultra-high resolution magnetic resonance imaging (MRI) and micro-computed tomography. STUDY DESIGN An experimental animal study was carried out. METHODS A total of 32 absorbable collagen sponge implantations into dorsal muscle were performed in rats of four different groups (control group, 0 µg BMP; recombinant human (rh)BMP-7 group, 3 µg rhBMP-7; rhBMP-2 group, 3 µg rhBMP-2; rhBMP-2/7 group, 3 µg rhBMP-2/7). Inflammatory reactions were evaluated by 11.7-T MRI (axial T2-weighted imaging using rapid acquisition with relaxation enhancement) at postoperative days 2 and 7. Bone volumes (BVs) of the induced ectopic bone were quantified at postoperative day 7. In addition, immunohistochemical staining for interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α was performed in samples obtained on postoperative day 2. Bone formation (BF)-to-inflammation (IM) ratios were calculated by dividing BVs by values of inflamed areas. RESULTS At postoperative day 2, the mean volume of T2 high area on MRI scans in BMP-2 group was significantly larger than that in control group. In contrast, the BMP-2/7 had no difference in the mean volume of T2 high area compared with the control group; however, there was no difference between the BMP-2/7 compared with BMP-2 group. At postoperative day 7, the volumes of T2 high area were not different between the groups. Mean BV of the newly formed bone on postoperative day 7 was significantly greater in BMP-2/7 group than in BMP-7 groups. No new bone formation was observed in control group. BF-to-IM ratio in BMP-2/7 group was significantly higher than those in BMP-2 and BMP-7 homodimer groups. Immunohistochemistry experiments did not reveal differences in expression levels of IL-1β, IL-6, or TNF-α in samples from BMP-2, BMP-7, and BMP-2/7 groups. CONCLUSIONS This study demonstrated that BMP-2/7 heterodimer has stronger bone induction ability without accompanying increased inflammatory reactions (the increased BF-to-IM ratio) than those observed by BMP-2 or BMP-7 homodimers. These results suggest that BMP-2/7 heterodimer can be an alternative to BMP-2 and BMP-7 homodimers in clinical applications, although further translational studies, including whether lower doses of BMP heterodimer may produce similar bone formation compared with the BMP homodimers but produce a reduced inflammatory response, are required.