Hiroshi Kitahara

Vertebral bone-marrow changes in degenerative lumbar disc disease. An MRI study of 74 patients with low back pain

We carried out MRI studies of 74 patients with end-plate and vertebral bone-marrow changes associated with degenerative lumbar disc disease. Abnormalities were classified into type A, with decreased signal intensities, and type B, with increased signal intensities on T1-weighted spin-echo images. Twenty-seven (73%) of the 37 patients with type-A changes had low back pain, in contrast to only four (11%) of the 37 patients with type-B changes. Lateral flexion-extension radiographs showed hypermobility in 26 patients (70%) with type-A changes, and in only six (16%) with type-B changes. Type-A changes correlated with segmental hypermobility and low back pain, while type-B changes were more common in patients with stable degenerative disc disease.

Quantitative Analysis of Bowel Gas Using Plain Abdominal Radiograph in Patients With Irritable Bowel Syndrome

OBJECTIVE:Ideally, the diagnosis of irritable bowel syndrome (IBS) would be achieved using a minimal number of procedures. It is presumed that bowel gas is related to IBS, and it is easily visualized by plain abdominal radiograph. In the present study, to clarify the relationship between IBS and the quantity of bowel gas, the measured bowel gas volume using plain abdominal radiographs was compared with the pathology of IBS.METHODS:Plain abdominal radiographs were digitized and transmitted to a computer (computed radiography) in 30 IBS patients and 30 normal controls. The quantity of bowel gas, determined as the pixel value on images and standardized by physique, was defined as the gas volume score (GVS). Using the mean ± 2SD of GVS in the control group as the normal score, IBS patients were divided into three groups: high, normal, and low. To examine the sequential reproducibility of a similar quantity of bowel gas, a second plain abdominal radiography was performed about 2 months later, and the GVS were compared. The colonic transit time was determined using radiopaque markers.RESULTS:There was a strong correlation between the quantities of bowel gas measured by two independent gastroenterologists. The mean GVS of IBS patients was significantly higher than that in the control group (p < 0.001). The sequential reproducibility was recognized in all 10 IBS patients. There was no significance between colonic transit time and GVS, nor between symptoms and GVS.CONCLUSIONS:Abdominal gas was analyzed objectively by using GVS, and GVS was considered to represent a useful tool for the diagnosis of IBS.

MECHANICAL STABILITY OF THE PEDICLE SCREW FIXATION SYSTEMS FOR THE LUMBAR SPINE

Five different pedicle screw systems: AO Fixator Interne, VSP Steffee plate, Luque ISF, modified Zielke, and Chibatype plate screw system (experimental device), were evaluated for biomechanical strength. A fatigue test for the screw, compressive, and torsional tests for the pedicle screw systems and a pull-out test of the pedicle screw were done. Even the Schanz screw, which showed the highest endurance limit, may be broken under the continuous loading condition in the body. The AO Fixator Interne and Steffee plate system themselves are rigid and are indicated for injuries that need reduction. The Luque ISF, modified Zielke, and Chiba-type plate screw systems, however, are indicated for degenerative lumbar disease requiring in situ fusion. There was a linear positive correlation between the bone mineral density of the vertebral body and the pull-out strength of the pedicle screw (correlation coefficient, 0.68). The fixation strength of the pedicle screw to the bone decreased remarkably in osteoporosis.

Scoliosis Associated with Syringomyelia

From January 1986 to December 1991, 1,059 patients with scoliosis of 20

Using cineradiography for continuous dynamic-motion analysis of the lumbar spine.

or more were reviewed, By magnetic resonance imaging, 43 patients were found to have syringomyelia. Thirty-eight patients had Chiarl type 1 malformation. Twenty-two of the patients were younger than 10 years, Scoliosis was the only presenting symptom in 32 patients, All patients had some neurologic abnormalities, Fifteen patients had left thoracic curves, The incidence of scoliosis with syringomyalia in our outpatient clinic was 4,0%: 18.4% in bays, and 2.6% in girls, Magnetic resonance imaging should be performad in patients who have abnormal reurologic findings.

Preoperative MRI analysis of patients with idiopathic scoliosis. A prospective study

Thirty-nine patients, 34 women and five men, underwent anterior decompression and interbody fusion for degenerative spondylolisthesis between February 1958 and August 1988. Their average age at surgery was 51 years (range, 34-74 years), and their average follow-up period was 12 years 7 months (range, 6 months to 30 years). Clinical evaluation was done by the score rating system of the Japanese Orthopaedic Association (JOA Score). Patients with JOA scores of 25 points or more were rated as “satisfactory.” Survivorship was analyzed by the method of Kaplan and Meier to determine the cumulative percentage of patients with satisfactory results. The following results were obtained: Seventy-six percent of the patients had satisfactory results for 10 years after the anterior interbody fusion, 60% for 20 years, and 52% for 30 years. Irrespective of their age at surgery, the patients generally maintained satisfactory results up to 65 years of age.

Idiopathic scoliosis in twins studied by DNA fingerprinting: THE INCIDENCE AND TYPE OF SCOLIOSIS

Study Design. Cineradiography was used to analyze continuous dynamic motion in the lumbar spine. Objectives. To identify motion patterns of the lumbar spine in asymptomatic volunteers and symptomatic patients with L4 degenerative spondylolisthesis, and to use the findings to discuss segmental instability in this disorder. Summary of Background Data. The use of radiographic findings to assess lumbar spine instability remains controversial. Although some studies have reported on lumbar kinematics during actual movement, the motion patterns in asymptomatic volunteers and symptomatic patients with L4 degenerative spondylolisthesis have not been fully clarified. Methods. While asymptomatic volunteers (n=20; mean age, 27; control group) and symptomatic patients with L4 degenerative spondylolisthesis (n=41; mean age, 63; degenerative spondylolisthesis [DS] group) flexed from a sitting neutral position and back to the neutral position (flexion course), cineradiography was used to record lateral segmental lumbar motions. Twelve frames were selected during the flexion course, and flexion-extension angle (f-e angle) and translation in the sagittal plane were measured at each motion segment (L2–L3, L3–L4, L4–L5, and L5–S1). The DS group was classified into 2 subgroups according to percentage of slip: DS group I, with a slip equal to or less than 15%; and DS group II, with a slip of more than 15%. The motion pattern was compared between the groups. Results. In the control group, f-e angle and translation at the L2–L3, L3–L4, and L4–L5 segments moved simultaneously, although the L5–S1 segment showed an initial delay. The amount of f-e angle and translation changed almost symmetrically. In both f-e angle and translation, the L4–L5 segment showed a large motion pattern. In DS group I (n=21), the L4–L5 segment showed a large motion pattern in f-e angle and an intermediate motion pattern in translation. In DS group II (n=20), the L4–L5 segment showed an intermediate motion pattern in f-e angle, and a small motion pattern in translation. The relative range of f-e angle at the L4–L5 segment had the largest range in DS group I, and the relative translation showed a serial decrease from the control group through DS group II. A significant correlation between f-e angle and translation (harmonious motion pattern) was noted at the L2–L3, L3–L4, and L4–L5 segments in the control group. The harmonious motion pattern at the L4–L5 segment was significantly less in the DS group than in the control group. The loss of harmonious motion pattern (disordered motion pattern) at L4–L5 was well-revealed in the DS group II. Conclusions. Motion analyses using cineradiography helped to explain the phenomena of lumbar spine kinematics. Based on continuous dynamic-motion analysis with cineradiography, large f-e angle and disordered motion pattern during the flexion-backward course in the DS group I was considered to be caused by segmental instability. The decreased translation and disordered motion pattern throughout the flexion course in the DS group II was considered to be caused by restabilization.

Natural history of scoliosis in children with syringomyelia

Study Design. A prospective trial of preoperative MRI study in patients with “idiopathic” scoliosis. Objectives. To investigate the prevalence of neural axis malformations and the clinical relevance of MRI in the evaluation of patients with idiopathic scoliosis undergoing surgical intervention. Summary of Background Data. With the development of MRI, neural axis abnormalities such as syringomyelia or Chiari malformations are increasingly being found in patients with “idiopathic” scoliosis. The risk of neurologic complications during correction of scoliosis without prior decompression surgery for syringomyelia has been documented; however, there have been no prospective studies for identifying the risk of neurologic complications as a result of scoliosis surgery in patients with asymptomatic neural axis malformations. Methods. A total of 250 patients who were classified as having “idiopathic” scoliosis at first presentation and admitted for spinal surgery were evaluated. All patients were examined for neural axis abnormalities using MRI. The presence of neurologic symptoms and abnormal neurologic signs was also examined before and after surgical intervention. Neurologic complications during scoliosis surgery were reviewed in patients with neural axis abnormalities. Results. There were 44 (18%) patients (13 males and 31 females) who had neural axis abnormalities on MRI, including syringomyelia with Chiari malformations in 22 patients, syringomyelia with tonsillar ectopia in 2, Chiari malformations in 13, tonsillar ectopia in 6, and low conus medullaris in 1. On clinical examination, 44 (18%) patients had abnormal neurologic signs and 26 (7%) patients complained of headache or back pain. There were significant differences between patients with and without neural axis abnormalities regarding the age at first visit, gender, curve pattern, sagittal profile of thoracic spine, presence of neurologic deficit, and complaint of pain. Only 12 of 44 patients needed neurosurgical treatment for foramen magnum decompression before correction of scoliosis. Neurologic status temporarily worsened in 3 patients, including 2 patients with neurosurgical treatment and 1 patient without neurosurgical treatment; however, there were no permanent neurologic complications as a result of scoliosis surgery. All patients without neurologic deficits or complaints of pain did not receive neurosurgical treatment, while they had no permanent neurologic complications. Conclusions. Foramen magnum decompression for neural axis malformations could prevent permanent neurologic complications during scoliosis surgery. There is little risk of neurologic complications in patients with “idiopathic” scoliosis whose neurologic status is normal, even if these patients have a neural axis malformation on MRI.

Visualisation of symptomatic nerve roots. Prospective study of contrast-enhanced MRI in patients with lumbar disc herniation

We investigated 21 pairs of twins for zygosity and idiopathic scoliosis. DNA fingerprinting confirmed that 13 pairs were monozygotic and eight were dizygotic. There was concordance for idiopathic scoliosis in 92.3% of monozygotic and 62.5% of dizygotic twins. Of the 12 pairs of monozygotic twins concordant for idiopathic scoliosis, six showed discordant curve patterns but eight had differences in Cobb angle of less than 10 degrees. Seven of the ten pairs of monozygotic twins had similar back shapes. Our findings suggest that there is a genetic factor in the aetiology of idiopathic scoliosis; they also indicate that there is a genetic factor in both the severity of the curve and the general shape of the back.