Tateru Shiraishi

Experimental scoliosis in melatonin‐deficient C57BL/6J mice without pinealectomy

Abstract:  The etiology of idiopathic scoliosis is unknown. Scoliosis with many characteristics closely resembling those seen in idiopathic scoliosis has been produced in young chickens and bipedal rats after pinealectomy. In this study, we induced experimental scoliosis in C57BL/6J mice without pinealectomy and melatonin treatment suppressed the development of scoliosis. A total of 100 mice were divided into four groups: 20 quadrupedal mice served as controls; 30 mice underwent resection of two forelegs and tail at 3 wk of age (bipedal mice); the remaining 20 quadrupedal and 30 bipedal mice received intraperitoneal melatonin (8 mg/kg BW) at 19:00 hr daily. Before killing, blood samples were collected in the middle of dark cycle and melatonin levels were measured by radioimmunoassay. Spine X‐ray and helical 3D‐CT were examined after killing at 5 months of age. The bipedal mice without a tail were able to walk with standing posture, whereas the quadrupedal mice did not walk with standing posture. In C57BL/6J mice, the serum melatonin was reduced to nearly zero; however, the normal level was restored in both bipedal and quadrupedal mice after the injection of melatonin. Scoliosis with rib humps developed in 29 of 30 bipedal and in five quadrupedal mice. None of mice with melatonin treatment developed scoliosis. The results suggest that melatonin deficiency in bipedal mice appears to play crucial role for development of scoliosis. Also the restoration of melatonin levels prevents the development of scoliosis.

New techniques for exposure of posterior cervical spine through intermuscular planes and their surgical application.

Study Design. Retrospective study of new muscle-preserving exposure techniques and their application to posterior cervical spine surgery. Objective. To describe muscle-preserving techniques for exposure of the posterior cervical spine, and to demonstrate how their application to a variety of posterior cervical spine surgeries for varying pathologies allows preservation of cervical mobility and stability. Summary of Background Data. Although surgical approaches through intermuscular planes have been applied to the extremities and anterior spinal column, to our knowledge, they have yet to be applied to the posterior cervical spine. Methods. We have used our new exposure techniques since 2000, applying them to selective mono laminoplasty (73 patients) for cervical myelopathy, muscle-preserving intervertebral foraminotomy (30 patients) for radiculopathy, posterior atlantoaxial instrumentation with muscle preservation (6 patients) for upper cervical instability, and muscle-reserving unilateral posterior arch recapping technique (11 patients) for cervical spinal cord tumors. A total of 120 patients were enrolled in this study. To evaluate surgical outcomes, we reviewed all their clinical records and pre- and postoperative images. Results. In selective mono laminoplasty, recovery rate according to Japanese Orthopaedic Association (JOA) scores averaged 60.7%. In muscle-preserving intervertebral foraminotomy, the averaged visual analogue scale for radicular pain decreased from 2.53 preoperatively to 0.47 postoperatively. Of 120 patients, 119 showed neither loss of curvature nor neck motion according to a comparison of pre- and postoperative plain x-rays, with only 1 patient who underwent unilateral posterior arch recapping technique for intramedullary ependymoma showing both. No trace of damage to the deep muscles was observed in any of the 17 patients who underwent posterior atlantoaxial instrumentation with muscle preservation or unilateral posterior arch recapping technique on postoperative magnetic resonance imaging. Conclusion. The muscle-preserving exposure techniques described here can be applied to a variety of posterior cervical spine surgeries for varying pathologies, with no adverse effect on cervical mobility or stability.

Similarities between giant cell tumor of bone, giant cell tumor of tendon sheath, and pigmented villonodular synovitis concerning ultrastructural cytochemical features of multinucleated giant cells and mononuclear stromal cells.

The authors investigated ultrastructural cytochemical features of multinucleated and mononuclear stromal cells in giant cell tumor of bone (GCTB), giant cell tumor of tendon sheath (GCTTS), and pigmented villonodular synovitis (PVNS). Specimens of each tumor, respectively numbering 4, 4, and 3, were stained for tartrate-resistant acid phosphatase (TRAP) reactions and examined with an electron microscope. In GCTB and GCTTS, multinucleated cells, including some relatively small giant cells, showed TRAP activity and cytoplasmic features characteristic of osteoclasts, and also sometimes abundant rough endoplasmic reticulum and siderosomes. A few giant cells with macrophage-like features and slight TRAP activity were demonstrated in GCCTS and PVNS. In each tumor type, mononuclear cells showing TRAP activity shared cytoplasmic features with osteoclast-like multinucleated giant cells, while some others had macrophage-like features, and still others were poorly differentiated; a few mononuclear cells showed cell-to-cell contact. Ultrastructural similarities of TRAP-positive mononuclear cells in the three tumor types, and those between TRAP-positive multinucleated cells in GCTB and GCTTS, suggest a common cell lineage capable of multinucleated giant cell formation in the 3 tumors, despite differing histogenesis.

Arthroscopic removal of intra-articular osteoid osteoma in the knee : case report and review of the literature

Abstract Osteoid osteoma is a relatively common benign bone tumor first described by Jaffe [1]. It most frequently arises in the long bones and exhibits a characteristic X-ray appearance, that is, a small radiolucent zone surrounded by reactive circumferential sclerosis (nidus) [2, 3]. Nocturnal pain, which can be alleviated by aspirin, is one of the characteristic clinical manifestations of this bone tumor [4]. Although it is relatively rare, osteoid osteoma can also arise in the intra-articular regions, and we found 14 such cases arising in the knee joint in the literature [5–18]. Patients with intra-articular osteoid osteoma often present with joint pain, intracapsular effusion, restricted motion, and muscle atrophy in the affected limb, which can be mistaken for more common entities, such as traumatic or degenerative pathologies of the joint. Furthermore, X-ray examination often fails to show the characteristic nidus that is typically seen in extra-articular osteoid osteoma and therefore can result in a delayed diagnosis. We herein present a case of intra-articular osteoid osteoma arising in the knee joint, which was successfully treated by arthroscopy, and review the reported cases of intra-articular osteoid osteoma arising in the knee.

The dural tube continues to expand after muscle-preserving cervical laminectomy

Introduction The purpose of this study was to elucidate the duration for which the dural tube continues to expand after muscle-preserving cervical laminectomy and the extent to which the expansion affects surgical outcomes. Methods We analyzed 83 patients with cervical myelopathy who underwent muscle-preserving selective laminectomy of three consecutive laminae between C4 and C6. On the lateral radiographs, parameters considered were C2-7 Cobb angles, range of flexion-extension neck motions, and C2-7 sagittal vertical axis. Neck alignment was classified into four types with lateral radiographs. Anteroposterior (AP) diameter of the dural tube was measured at mid-level of the C5 vertebral body on T2 sagittal image. Expansion ratio (ER) was defined as the extent of expansion at a particular time divided by the final extent of expansion of the dural tube diameter. Operative outcomes were examined using the Japanese Orthopaedic Association scores. Results The mean age was 62.3 years, and the mean follow-up period was 2 years and 9 months. AP diameter of the dural tube had been expanding until 1-year after surgery. ER in cases with kyphosis was lower at 6 months than that in cases without kyphosis, indicating that the speed of dural expansion was slower in cases with kyphosis. There was no correlation between the extent of expansion of the dural tube and neurological recovery. Conclusions The dural tube continued to expand for approximately 1-year after surgery. The dural tube of patients with kyphosis slowly expanded possibly because of the hardness of the dura mater. A small extent of dural expansion does not necessarily indicate bad surgical outcomes.

Characteristic findings on imaging of cervical spondylolisthesis: Analysis of computed tomography and X-ray photography in 101 spondylolisthesis patients

Introduction The characteristics of cervical spondylolisthesis are not currently fully understood, because of the shortage of reports covering the large population of patients with cervical spondylolisthesis. The purpose of this study was to elucidate the characteristics of cervical spondylolisthesis by examining a relatively large number of cases. Methods We analyzed 101 cases with more than 2 mm of vertebral listhesis as determined from X-ray or computed tomography (CT) images among 731 patients who underwent surgery at a single institute. We considered the C2-7 angle, range of motion, and C2-7 sagittal vertical axis on lateral X-ray images. From sagittal CT images, classifications into five grades based on the slipped disc and adjacent caudal levels were made. We examined the orientation of facet joints at the slipped level using axial CT images. Results Spondylolisthesis was recognized in 101 cases at 124 levels. Anterior and posterior spondylolisthesis were detected in 68 and 40 cases, respectively. Anterior spondylolisthesis developed predominantly at C3 or C4, usually at the level adjacent to the narrowed disc, or at C7, adjacent to the stiffened thoracic spine. The disc height was relatively preserved at the anterior slipped level. Posterior spondylolisthesis developed predominantly at the level of the significantly narrowed disc associated with advanced intervertebral osteoarthritis. At the segment with listhesis in the lower cervical spine, the direction of the facet joint in the axial plane tended to be posteromedial. Conclusions Cervical degenerative spondylolisthesis was classified into two types. The first and more common listhesis occurred adjacent to stiffened levels, and anterior slippage was common in this type. The second and less common listhesis occurred within progressively degenerated segments, and posterior slippage was prominent. We have uniquely described the morphological changes in orientation of the cervical facet joints at the slipped level in the transverse plane.

Posterior spinal cord shift does not affect surgical outcomes after muscle-preserving selective laminectomy

Postoperative posterior spinal cord shift (PSS) has been considered a required radiographic endpoint of posterior decompression procedures. To achieve PSS, laminoplasty for cervical compressive myelopathy (CCM) has been consecutively performed on four or more laminae (C2-C7, C3-C7, or C3-C6). However, the clinical significance of PSS remains controversial. By selecting the surgically treated laminae, selective laminectomy (SL) can achieve adequate decompression without disturbing the extensor musculature and facet joints. The clinical features and radiological findings from 162 patients with CCM whose decompression included C4/5 level were investigated. The postoperative C2-C7 angle, PSS at C4/5 level, and laminectomy width were measured. Radiologic factors affecting PSS and the relationship between PSS and functional outcome were analyzed. Smaller PSS was observed in cases involving two or fewer consecutive laminectomies than in cases involving three or more consecutive laminectomies. The number of consecutive laminae (CLs) surgically treated and the postoperative C2-C7 angle correlated with PSS. Multiple linear regression analyses showed that the number of surgically treated CLs was the greatest predictor of PSS. No correlation was observed between PSS and the recovery rate (RR) of the Japanese Orthopaedic Association (JOA) score; RR of the JOA score was not affected even in patients with no PSS. PSS was affected by the number of CLs surgically treated and the postoperative C2-C7 angle. The magnitude of PSS never affected the RR of JOA score after SL. Therefore, for patients with CCM, PSS is not mandatory to obtain satisfactory functional recovery.

Extremely high preoperative C7 slope limits compensatory cervical lordosis after muscle-preserving selective laminectomy

PurposeA high C7 slope induces C2–C7 lordosis to compensate for cervical sagittal balance adjustments. A muscle-preserving selective laminectomy (SL) can maintain this compensation postoperatively. This study evaluated the effect of an extremely high C7 slope on C2–C7 lordotic compensation following SL.MethodsThis study enrolled 151 cervical compressive myelopathy patients who underwent SL. Lateral cervical spine radiographs were taken before surgery and during final follow-up. Patients were divided into extremely high C7 slope (≥ 30°) (EH) and non-high C7 slope (< 30°) (NH) groups and the influence of a high C7 slope on radiological and surgical outcomes was examined.ResultsMean age was higher in group EH (p < 0.001). Preoperatively, patients in group EH had a larger C2–C7 sagittal vertical axis (SVA) (p = 0.001) and greater cervical lordosis (p < 0.001). Although C2–C7 SVA increased after surgery, mean C2–C7 angle of group EH decreased. Mismatches between C7 slope and C2–C7 angle increased for group EH postoperatively (p = 0.015). Postoperative Japanese Orthopedic Association (JOA) score and recovery rate (RR) were slightly lower in group EH (p = 0.001 and p = 0.006, respectively). Multiple linear regression analyses revealed that extremely high C7 slope, not age, affected the RR of JOA score (p = 0.006).ConclusionsPatients in group EH were older and had highly compensated cervical sagittal alignment preoperatively. They demonstrated postoperative cervical sagittal balance mismatch increases and slightly worse functional recovery. An extremely high C7 slope limited compensatory cervical lordosis following SL.Graphical abstractThese slides can be retrieved under Electronic Supplementary Material.

A Rare Case of an Osteoid Osteoma of the Rib Treated under Computed Tomography Guidance: A Case Report and Review of the Literature

Osteoid osteoma (OO) usually occurs in the extremities of young adults. The tumor can arise in any part of the skeletal tissue; however, it is rarely found in the rib, with limited reports to date. In this report, we present a rare case of OO arising in the rib, which was successfully treated under computed tomography guidance with minimal invasiveness. At the final follow-up after 4 years, no local recurrence was observed.