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Purpose : To analyze extraosseous signal changes (ESCs) on magnetic resonance imaging (MRI) in pediatric patients with stress fractures occurring in the lamina. Methods : This study was a retrospective review of 69 consecutive pediatric patients with stress fractures occurring in the lamina. We analyzed MRI scans obtained at the first presentation. Results : We used mainly axial short tau inversion recovery images acquired through the pedicle of these 84 fracture sites to identify the ESCs. These were then divided into three groups: “invisible” when no ESC was detected, “periosteal” for ESC seen on only the dorsal side of the lamina, and “perimuscular” for ESC distinctly spread around / in the paravertebral muscles. In total, 78 (92.9%) fracture sites showed ESCs on the dorsal side of the lamina among which 72 ESCs were located on only the “dorsal” side, while 6 ESCs were on the ventral side against the transverse process. Conclusion : ESCs on MRI were detected in more than 90% of patients before stress fracture became apparent in the lamina, which was considered similar to findings of periosteal thickening / edema detected at the onset of stress fracture in long bone.

Study design: A study using rat spondylolisthesis models. Objective: To elucidate the mechanism for correction of vertebral rounding deformity. Summary of Background Data: Vertebral rounding deformity is the strongest risk factor for high-grade slippage associated with spondylolisthesis in adolescents. We previously reported that inadequate endochondral ossification of the anterior upper corner of the vertebral growth plate in response to mechanical stress could be the pathological mechanism of vertebral rounding deformity. Methods: We created a model of spondylolisthesis using 4-week-old rats. They were divided into a tail suspension group that underwent tail suspension to decrease mechanical stress starting at 2 weeks postoperatively and a ground control group with no intervention. Radiographs and micro-computed tomography scans were obtained once weekly for 6 weeks postoperatively. The lumbar spines were then harvested for histological analysis. Immunohistochemical studies detected types I, II, and X collagen in the growth plate cartilage. Bone histomorphometrical analysis was also performed. Results: Radiological and histological evidence in the ground control group showed progress the rounding deformity with time as previously reported. Formation of normal cancellous bone was observed radiologically over time in the tail suspension group, indicating correction of rounding deformity. Histologically, the site showing radiological evidence of correction was derived from cartilage tissue. After starting tail suspension, the growth plate stained positive for type X collagen and the corrected site stained for types II and X collagen in a mosaic pattern. Chondrocytes expressing types I and II collagen and tartrate-resistant acid phosphatase-positive cells were also present at the corrected site. Histomorphometrically, more endochondral bone was detected at the corrected site than in the posterior aspect of the normal growth plate. Conclusion: Correction of vertebral rounding deformity was associated with improvement of chondrocyte differentiation, furthermore, there is possible involvement of a third mechanism, namely transchondroid bone ossification., It is possible to correct the rounding deformity of the vertebral body associated with isthmus slippage by decrease the load on the vertebral body in pediatric patients. In addition to improved chondrocyte differentiation and promotion of redifferentiation, there is possible involvement of a third mechanism, namely transchondroid bone ossification.

Transforaminal endoscopic discectomy has been established as the least minimally invasive spine surgical procedure because it avoids the surgical morbidity from surgical dissection and denervation of normal anatomy responsible for the functional stability of the spine. There have been few reports on endoscopic spine surgery for professional athletes who are dependent on the preservation of vital anatomy to maintain the highest level of function. This report is on five Japanese professional baseball players who underwent transforaminal endoscopic foraminoplasty-discectomy with pulsed radiofrequency thermal annuloplasty under the local anesthesia. There were no adverse surgical events nor complications. Three athletes suffered from discogenic back pain, one from symptomatic herniated nucleus pulposus (HNP), and another player from sciatica due to foraminal stenosis. Three players decided to undergo surgery at the beginning of the off-season. Therefore, they returned to professional play at the beginning of the following season. The remaining two players underwent surgery just before the beginning of the next season. They all returned to play sooner than with traditional open decompression. Two players returned to play about one month after the start of the season. All five players quickly returned to their sport within three months despite the rigors required of their sport to maintain high proficiency and were able to complete the season.

Full-endoscopic spinal surgery was first developed for the lumbar herniated nucleus pulposus. Mainly, there are two types in the full-endoscopic lumbar surgery : i.e., transforaminal (TF) and interlaminar approach. The surgery can be done under the local anesthesia for the TF approach ; therefore, we need to further develop the TF approach to variety of the spinal disorders. Recently, the TF full-endoscopic surgery has been applied for the spinal canal stenosis. First, transforaminal full-endoscopic lumbar foraminoplasty for the foraminal stenosis ; then, transforaminal lumbar lateral recess decompression for the lateral recess stenosis has been developed. Finally, we have developed the surgical technique to decompress the central stenosis via TF approach under the local anesthesia. Prior to initiate the clinical case, we have attempted the lumbar undercutting laminectomy using a fresh cadaveric spine. After we technically confirmed that the transforaminal full-endoscopic lumbar undercutting laminectomy (TE-LUL) is possible, we applied the technique to the patient whose lung capacity did not allow general anesthesia. The 72 years old female patient with central canal stenosis could be improved her left leg pain and muscle weakness after TE-LUL under the local anesthesia. In this paper, we introduce the surgical technique of the TE-LUL and discuss of the efficacy of the TE-LUL.

Background : There is few reports evaluated accurately the pain generator of low back pain in elite athletes. The purpose of this report was to show case series and to investigate the cause of unidentified low back pain of elite athletes. Methods : Twenty-three adult elite athletes consulted our sports spine clinic to seek a second opinion for low back pain between April 2013 and March 2016. Their cause of low back pain had not been identified by nearby doctor. Spine surgeons had diagnosed using diagnostic injection and STIR-MRI and the final diagnosis made by the spine surgeon were collected. Results : The mean age of 23 patients (16 male, 7 female) was 30.4 years. The most common sport played was baseball. The final diagnosis made by a spine surgeon was as follows : disc related low back pain (n = 12), facet joint arthritis (n = 5), vertebral endplate injury (n = 4), early-stage lumbar spondylolysis (n = 1), supraspinous ligament injury (n = 1). Conclusions : A thorough medical interview, careful physical examination, appropriate diagnostic imaging, and injection block examination can effectively identify the cause of low back pain.

A 73-year-old woman complained of right medial side of scapular pain associated with winged scapula to miss without observing the back in minute detail. Additional treatment was required due to overlooking caused by insufficient examination. We performed micro-endoscopic foraminotomy that provided the disappearance of scapular pain and improvement of winged scapula in relatively early. It was commonly said that winged scapula is an extremely rare condition that causes dysfunction of the upper extremities. We suggest that there are the meaning of winged scapula in diagnosis and the importance of physical examination. Further studies should be required to research the morbidity of winged scapula associated with cervical disease. By sharing our experience of this attention arousing case, we provide information not to repeat the same mistakes.

Introduction: In past biomechanical studies, repetitive motion of lumbar extension, rotation, or a combination of both, frequently seen in batting or pitching practice in baseball, shooting practice in soccer, and spiking practice in volleyball, have been considered important risk factors of lumbar spondylolysis. However, clinically, these have been identified in many athletes performing on a running track or on the field, which requires none of the practices described above. The purpose of this study was to verify how much impact running has on the pathologic mechanism of lumbar spondylolysis. Methods: In study 1, 89 consecutive pediatric patients diagnosed with lumbar spondylolysis at a single outpatient clinic between January 2012 and February 2017 were retrospectively analyzed. In study 2, motion analysis was performed on 17 male volunteers who had played on a soccer team without experiencing low back pain or any type of musculoskeletal injury. A Vicon motion capture system was used to evaluate four movements: maximal effort sprint (Dash), comfortable running (Jog), instep kick (Shoot), and inside kick (Pass). Results: In study 1, 13 of the 89 patients with lumbar spondylolysis were track and field athletes. In study 2, motion analysis revealed that the hip extension angle, spine rotation angle, and hip flexion moment were similar in Dash and Shoot during the maximum hip extension phase. The pelvic rotation angle was significantly greater in the kicking conditions than in the running conditions. Conclusions: Kinematically and kinetically, the spinopelvic angles in Dash were considered similar to those in Shoot. Dash could cause mechanical stress at the pars interarticularis of the lumbar spine, similar to that caused by Shoot, thus leading to spondylolysis.

Background: Despite facet joints being three-dimensional structures, previous computed tomography and magnetic resonance imaging studies have evaluated facet joint orientation in only the axial plane. Facet joint orientation in the sagittal plane has rarely been studied using these imaging techniques. The aim of this study was to elucidate facet joint orientation in both the axial and sagittal planes on computed tomography. Methods: A total of 568 patients (343 men, 225 women) (excluding orthopedic outpatients) for whom abdominal and pelvic computed tomography scans were obtained at our hospital between September 2010 and October 2012 were included. Mean age was 63 (range 21-90) years. Patients were divided into a degenerative spondylolisthesis group (67 patients; 30 men, 37 women) and a control group (313 patients; 313 men, 188 women). Facet joint orientation was evaluated in the control group according to patient age (≤50, 51-60, 61-70, or ≥71 years). The findings in the control group were then compared with those in the degenerative spondylolisthesis group. The orientation of the lumbar facet joints at each level was measured in the axial and sagittal planes on computed tomography images. Results: Facet joint angles decreased with age at L4/5 and L5/S1 in women in the axial plane and at L4/5 in men and L3/4 and L4/5 in women in the sagittal plane. The variation in facet joint angle was greatest at L4/5 in women. Patients with degenerative spondylolisthesis showed more sagittally and horizontally oriented facet joints in the axial and sagittal planes; facet tropism showed an association with degenerative spondylolisthesis in the axial plane. Conclusions: The axial and sagittal orientation of facet joints in the lower lumbar vertebra, especially L4/5, was negatively correlated with age. This finding could help to explain why older people are more prone to degenerative spondylolisthesis.

Introduction. Synovial cysts rarely develop in the atlantoaxial joint. We report a case of posterior C1-2 laminectomy for a synovial cyst of the atlantoaxial joint which passed through the dorsal dura and put pressure on the cervical spinal cord. Case Presentation. A 62-year-old man with rapid progression of pain and weakness in the left upper extremity presented to our hospital. A cervical spine X-ray showed left C5-6 and C6-7 stenoses. A cervical magnetic resonance imaging showed an intradural extramedullary cystic lesion on the right side of the ventral cervical spinal cord at the C1-2 level and severe compression of the cervical spinal cord. Because a cyst was partially enhancing, a tumor lesion was not identifiable. Due to severe spinal cord compression, we performed intradural cyst removal via a posterior intradural approach with C1-2 laminectomy and left-sided C5-6 and C6-7 foraminotomies. One year after surgery, the cyst did not recur, and atlantoaxial instability did not appear. Discussion. A compressive lesion on the cervical spinal cord was not identified preoperatively as a synovial cyst. However, intraoperative and pathological findings suggested that the compressive lesion can be a synovial cyst which passed through the dorsal dura. The surgical treatment strategy for a synovial cyst of the atlantoaxial joint is controversial due to factors, such as the presence of atlantoaxial instability, level of cyst causing compression of the cervical spinal cord, severity of myelopathy, and cyst location. In the present study, the cervical spinal cord was highly compressed and the cyst was located on the right side of the cervical spinal cord; we chose cyst removal through a posterior intradural approach with C1-2 laminectomy.