Validating the Definition of Lumbar Instability-A Cross-Sectional Study with 420 Healthy Volunteers.

: Low back pain is thought to be caused by lumbar instability. To date, multiple definitions of radiological lumbar instability have been used without verifying the "normal range" of the lumbar segmental mobility. Ideally, normative data for lumbar mobility in healthy individuals are required to establish an acceptable threshold for lumbar instability.

Reliability of Conventional Two-Dimensional Magnetic Resonance Imaging for Diagnosing Extraforaminal Stenosis in Lumbosacral Transition.

Introduction: Three-dimensional (3D) magnetic resonance imaging (MRI) is reportedly superior to two-dimensional (2D) MRI for diagnosing lumbar foraminal stenosis at L5-S1. In this study, we strictly distinguished the intra- and extraforaminal regions and compared the diagnostic reliability and accuracy of 2D and 3D MRI in each region.

Methods: A total of 92 surgical cases of unilateral L5 radiculopathy were selected for imaging analysis, including 46 of foraminal stenosis at L5-S1 (Group F) and 46 of intraspinal canal stenosis at L4-5 (Group C) (48 men, 44 women; mean age, 66 years).

Radical decompression without fusion for L5 radiculopathy due to foraminal stenosis.

Background: The highest incidence of lumbar foraminal stenosis (LFS) occurs in the L5-S1 segment and its anatomical features differ from those of other segments. Few previous reports have exhaustively assessed surgical outcomes after decompression surgery, limiting the materials to patients with LFS at the L5-S1 segment. We aimed to prospectively investigate instability and neurological improvement following our novel surgical technique for LFS at L5-S1, named "radical decompression" of the nerve root.

Are T1-Weighted Three-Dimensional Magnetic Resonance Images Inferior to T2-Weighted Images for Diagnosing Lumbar Foraminal Stenosis in the Fifth Lumbar Nerve Root? A Prospective, Comparative Study in Identical Patients.

Introduction: Imaging analysis of foraminal stenosis in the fifth lumbar (L5) nerve root remains to be a challenge because of the anatomical complexity of the lumbosacral transition. T2-weighted three-dimensional (3D) magnetic resonance images (MRI) have been dominantly used for diagnosis of lumbar foraminal stenosis, while the reliability of T1-weighted images (WI) has also been proven. In this study, we aim to compare the reliability and reproducibility of T1- and T2-weighted 3D MRI in diagnosing lumbar foraminal stenosis (LFS) of the L5 nerve root.

Imaging diagnosis of lumbar foraminal stenosis in the fifth lumbar nerve root: reliability and reproducibility of T1-weighted three-dimensional lumbar MRI.

Background: Various magnetic resonance imaging (MRI) techniques have been reported in detection of lumbar foraminal stenosis (LFS), especially for T2-weighted three-dimensional MRI (3D-MRI) describing the shape of nerve roots. The detection of LFS in the fifth lumbar nerve root (L5 root), however, is still less reliable compared to other lumbar nerve roots. Then we have been using T1-weighted 3D-MRI aiming to depict the shape of, and also pathology affecting the L5 root.

The Effect of the COVID-19 Pandemic on South Korea's Stock Market and Exchange Rate.

This study examines COVID-19 pandemic effects on the stock market and exchange rate of South Korea. With daily data from January 2, 2019 to August 31, 2020, we show that a new infection spike increases stock price index volatility and decreases foreign investors' holdings of domestic stocks, and indirectly leads to the depreciation of the South Korean won. We indicate that investors may have repurchased the South Korean won seven days after an infection spike, thereby slightly increasing its value.

Reoperation Rates after Laminoplasty for Cervical Disorders: A 26-Year Period Survival Function Method Analysis.

Introduction: Laminoplasty is a common surgery for cervical myelopathy. Previous studies have analyzed the reoperation rates in posterior decompression surgeries of the cervical spine. However, few studies have solely focused on midline-splitting laminoplasty (MSL) using a large number of patients.

Rate of spinal surgery in a rapidly aging society: the 27-year changes in Miyagi prefecture, Japan.

Background: Japan has had a rapidly aging population during the past 30 years. This study aimed to investigate longitudinal changes in the surgical rate for spinal disorders in Miyagi Prefecture (2.35 million inhabitants) with a similar population composition to Japan.

Lumbosacral Transitional Vertebrae Cause Spinal Level Misconception in Surgeries for Degenerative Lumbar Spine Disorders.

Human lumbar spine usually consists of five vertebrae; however, some individuals have vertebral anomalies with four or six lumbar vertebrae because of sacralized fifth lumbar vertebra (L5 sacralization) or lumbarized first sacral vertebra (S1 lumbarization), respectively. These vertebral anomalies are called lumbosacral transitional vertebra (LSTV). Although LSTV is an asymptomatic anomaly, it is known to cause misconception in spinal counts and in spinal level at lumbar spinal surgery.

Increasing Incidence of Degenerative Spinal Diseases in Japan during 25 Years: The Registration System of Spinal Surgery in Tohoku University Spine Society.

Spinal disorders affect mainly older people and cause pain, paralysis and/or deformities of the trunk and/or extremities, which could eventually disturb locomotive functions. For ensuring safe and high-quality treatment of spinal disorders, in 1987, the Tohoku University Spine Society (TUSS) was established by orthopedic departments in Tohoku University School of Medicine and its affiliated hospitals in and around Miyagi Prefecture. All spine surgeries have been enrolled in the TUSS Spine Registry since 1988.

Elderly-onset degenerative "lumbar spondylotic myelopathy" in a patient with a low-placed spinal cord successfully treated by laminotomy: a case report.

The authors report a rare case of elderly-onset "lumbar spondylotic myelopathy" occurred on a low-placed spinal cord compressed at multiple levels with thickened ligamenta flava. A posterior decompression surgery could alleviate neurological symptoms successfully instead of untethering of the spinal cord, a widely accepted surgery for tethered cord.

Bilateral spondylolysis of inferior articular processes of the fourth lumbar vertebra: a case report.

Lumbar spondylolysis, a well known cause of low back pain, usually affects the pars interarticularis of a lower lumbar vertebra and rarely involves the articular processes. We report a rare case of bilateral spondylolysis of inferior articular processes of L4 vertebra that caused spinal canal stenosis with a significant segmental instability at L4/5 and scoliosis. A 31-year-old male who had suffered from low back pain since he was a teenager presented with numbness of the right lower leg and scoliosis.

Fracture and contralateral dislocation of the twin facet joints of the lower cervical spine.

Purpose: The combination of a facet fracture and a contralateral facet dislocation at the same intervertebral level of the cervical spine (a fracture and contralateral dislocation of the twin facet joints) has not been described in detail. The aims of this study are to report a series of 11 patients with this injury, to clarify the clinical features and to discuss its pathomechanism.

Methods: Among 251 patients with lower cervical spine fractures and/or dislocations surgically treated, 11 (9 males and 2 females, averaged age, 52 years) had this kind of injury.

Cervical myelopathy due to degenerative spondylolisthesis.

Objective: To investigate clinical-radiological features of cervical myelopathy due to degenerative spondylolisthesis (DSL).

Methods: A total of 448 patients were operated for cervical myelopathy at Nishitaga National Hospital between 2000 and 2003. Of these patients, DSL at the symptomatic disc level was observed in 22 (4.

Severe facet joint arthrosis caused c7/t1 myelopathy: a case report.

Cervical myelopathy is caused by degenerative processes of the spine including intervertebral disc herniation and posterior spur usually developing at C3/4 to C5/6. C7/T1 single level myelopathy is very rare because of the anatomical characteristics. Facet joint arthrosis can be a cause of cervical myelopathy but only a few cases have been reported.

Eighteen microsatellite loci in Salix arbutifolia (Salicaceae) and cross-species amplification in Salix and Populus species.

Salix arbutifolia is a riparian dioecious tree species that is of conservation concern in Japan because of its highly restricted distribution. Eighteen polymorphic loci of dinucleotide microsatellites were isolated and characterized. Among these, estimates of the expected heterozygosity ranged from 0.

Spine-shortening vertebral osteotomy in a patient with tethered cord syndrome and a vertebral fracture. Case report.

The authors report a rare case of tethered cord syndrome with low-placed conus medullaris complicated by a vertebral fracture that was successfully treated by a spine-shortening vertebral osteotomy. The patient was a 57-year-old woman whose neurological condition worsened after a T-12 vertebral fracture because a fracture fragment and the associated local kyphotic deformity directly compressed the tethered spinal cord. An osteotomy of the T-12 vertebra was performed in order to correct the kyphosis, remove the fracture fragment, and reduce the tension on the spinal cord.

Sagittal alignment changes after thoracic laminectomy in adults.

Object: The increased kyphosis after thoracic laminectomy in adult patients was retrospectively evaluated and various factors affecting this spinal deformity were analyzed.

Methods: The authors conducted a retrospective study of 58 cases in which laminectomy was performed and more than half of the facet joints were left intact. The study group included 44 men (mean age 59 years) and 14 women (mean age 61 years) with thoracic myelopathy due to ossifications of the ligamentum flavum and/or the posterior longitudinal ligament or due to posterior bone spurs.

Spinal dumbbell tumors: an analysis of a series of 118 cases.

Object: The authors analyzed a series of 118 cases of spinal dumbbell tumors to elucidate the feature of the tumors.

Methods: Of 674 cases of spinal cord tumors, the incidence of dumbbell tumors was studied. The tumors were analyzed, and the authors focus on the distribution of age and sex, the pathological diagnoses, their locations, Eden classification, and the surgical methods used.

Thoracic myelopathy in Japan: epidemiological retrospective study in Miyagi Prefecture during 15 years.

Thoracic myelopathy is defined as spinal cord compression in the thoracic region, leading to sensory and motor dysfunctions in the trunk and lower extremities, and can be caused by various degenerative processes of the spine. Thoracic myelopathy is rare, and there are many unsolved problems including its epidemiological and clinical features. We have established a registration system of spinal surgeries, which covered almost all surgeries in Miyagi Prefecture, and enrolled the data of 265 patients with thoracic myelopathy from 1988 to 2002.

Flexion-distraction injuries in the thoracolumbar spine: an in vitro study of the relation between flexion angle and the motion axis of fracture.

A new concept, the motion axis of fracture (MAF), which is defined as the transitional point from anterior compressive to posterior splitting failure on a lateral radiograph, has provided a true understanding of the mechanisms of flexion-distraction injuries in clinical cases. This study was designed to produce in vitro injuries that have MAFs and to clarify the relation between the flexion angle and the MAF location. Adolescent porcine thoracolumbar spines were exposed to a vertical compressive load to failure at three different flexion angles and then examined radiographically.