Yasuo Morio

Correlation Between Operative Outcomes of Cervical Compression Myelopathy and Mri of the Spinal Cord

Study Design. Magnetic resonance images of cervical compression myelopathy were retrospectively analyzed in comparison with surgical outcomes. Objectives. To investigate which magnetic resonance findings in patients with cervical compression myelopathy reflect the clinical symptoms and prognosis, and to determine the radiographic and clinical factors that correlate with the prognosis. Summary of Background Data. Signal intensity changes of the spinal cord on magnetic resonance imaging in chronic cervical myelopathy are thought to be indicative of the prognosis. However, the prognostic significance of signal intensity change remains controversial. Methods. The participants in this study were 73 patients who underwent cervical expansive laminoplasty for cervical compression myelopathy. Their mean age was 64 years, and the mean postoperative follow-up period was 3.4 years. The pathologic conditions were cervical spondylotic myelopathy in 42 patients and ossification of the posterior longitudinal ligament in 31 patients. Magnetic resonance imaging (spin-echo sequence) was performed in all the patients. The transverse area of the spinal cord at the site of maximal compression was computed, and spinal cord signal intensity changes were evaluated before and after surgery. Three patterns of spinal cord signal intensity changes on T1-weighted sequences/T2-weighted sequences were detected as follows: normal/normal, normal/high-signal intensity changes, and low-signal/high-signal intensity changes. Surgical outcomes were compared among these three groups. The most useful combination of parameters for predicting prognosis was determined using a stepwise regression analysis. Results. The findings showed 2 patients with normal/normal, 67 patients with normal/high-signal, and 4 patients with low-signal/high-signal change patterns before surgery. Regarding postoperative recovery, the preoperative low-signal/high-signal group was significantly inferior to the preoperative normal/high-signal group. There was no significant difference between the transverse area of the spinal cord at the site of maximal compression in the normal/high-signal group and the low-signal/high-signal group. A stepwise regression analysis showed that the best combination of surgical outcome predictors included age (correlation coefficient R = −0.348), preoperative signal pattern, and duration of symptoms (correlation coefficient R = −0.231). Conclusions. The low-signal intensity changes on T1-weighted sequences indicated a poor prognosis. The authors speculate that high-signal intensity changes on T2 weighted images include a broad spectrum of compressive myelomalacic pathologies and reflect a broad spectrum of spinal cord recuperative potentials. Predictors of surgical outcomes are preoperative signal intensity change pattern of the spinal cord on radiologic evaluations, age at the time of surgery, and chronicity of the disease.

Cross-Sectional and Longitudinal Study of Osteoporosis in Patients with Rheumatoid Arthritis

Abstract: To elucidate the pathology of osteoporosis associated with rheumatoid arthritis (RA), bone mass measurements were performed in 146 female patients with RA and compared with those in 150 age-matched female patients with osteoarthritis (OA) and postmenopausal osteoporosis (OP). Bone mineral density (BMD) was measured at the lumbar spine (L-BMD), the mid-radius (MR-BMD) and the calcaneus (C-BMD) by dual-energy X-ray absorptiometry (DXA), and at the distal radius by peripheral quantitative computed tomography (pQCT). The RA group showed significantly lower BMD at all sites, except L-BMD, than the OA group. Compared with the OP group, the RA group showed a significantly higher L-BMD but no difference at other sites. BMD in RA decreased with disease severity at all sites and lean body mass was highly correlated with L-BMD and C-BMD. Cross-sectional analysis revealed early bone loss at the distal radius and a decrease of L-BMD, MR-BMD, and C-BMD with disease duration. Longitudinal analysis showed that the annual loss of L-BMD, MR-BMD and C-BMD tended to be lower with increasing disease duration. Glucocorticoid administration had no influence on L-BMD, MR-BMD or C-BMD. We concluded that, unlike postmenopausal osteoporosis, osteoporosis associated with RA is characterised by relatively preserved bone mass in the axial bone and marked loss in the peripheral bone. The risk factors for generalised osteoporosis are a long disease duration, severity of disease, and decreased lean body mass.

Does increased signal intensity of the spinal cord on MR images due to cervical myelopathy predict prognosis

We examined whether or not high signal intensity change on magnetic resonance imaging of the spinal cord of patients with cervical myelopathy is related to the clinical symptoms and prognosis. Twenty-five patients with cervical myelopathy were treated by decompressive surgery which involved laminoplasty or decompressive anterior interbody fusion. The pathological conditions were cervical disc herniation (n = 8), ossification of the posterior longitudinal ligament in the cervical spine (n = 7), and cervical spondylotic myelopathy (n = 10). The spinal cord compression and the intramedullary signal intensity at the site of maximum compression were evaluated pre- and postoperatively using T1- and T2-weighted images. There was no significant relationship between spinal cord compressive change and clinical symptoms. Patients in whom the high signal change of the spinal cord on T2-weighted sequence recovered after decompressive surgery had better recovery from clinical symptoms, but a statistical significance was not found. We suggest that signal changes on T2-weighted images may reflect pathological changes but cannot be used to predict prognosis at present.

Lumbar disc degeneration and segmental instability: a comparison of magnetic resonance images and plain radiographs of patients with low back pain

We analyzed disc space height, angular displacement, tilting movement, and horizontal displacement in 109 patients with low back pain and/or sciatica, on plain radiographs of the lumbar spine. These parameters were compared with the grade of disc degeneration as evaluated by magnetic resonance imaging with the aim of studying lumbar segmental instability. Disc space height decreased in proportion to the grade of disc degeneration. Angular displacement was significantly less with severe disc degeneration, accompanied by a tendency to stabilization of the motion segment. Tilting movement and horizontal displacement. did not correlate with the grade of disc degeneration. Lumbar segmental instability was recognized at all levels even in individuals who appeared to be normal or to have mild disc degeneration. The incidence of lumbar segmental instability at the L3-4 level was significantly higher in patients with normal discs or mild disc degeneration. At the L4-5 and L5-S levels it did not differ between different grades of disc degeneration.

Clinicoradiologic study of cervical laminoplasty with posterolateral fusion or bone graft.

Study Design. A retrospective study of cervical expansive laminoplasty for cervical myelopathy from a clinicoradiologic perspective. Objective. To clarify the correlation among sagittal curvature of the cervical spine, cervical range of motion, sagittal plane translation, spinal cord atrophy, and myelopathic symptoms in patients who have undergone laminoplasty. Summary of Background Data. Laminoplasties were developed to diminish the undesirable effects of laminectomy, which include postoperative kyphotic changes and instability. However, the superiority of laminoplasty over laminectomy remains controversial. Methods. Fifty-one patients with cervical spondylotic myelopathy or ossification of the cervical posterior longitudinal ligament who underwent laminoplasty were radiologically assessed before and after surgery. The index of the sagittal curvature, intervertebral range of motion, listhesis, and the transverse area of the spinal cord at the site of maximal compression were measured to evaluate interrelations among those parameters and myelopathic symptoms. Results. There were no patients with kyphotic curvature before surgery. The postoperative curvature tended to be less lordotic. This tendency did not adversely affect postoperative symptoms. The intervertebral range of motion was significantly decreased except at C1–C2. The final C4–C5 range of motion and the postoperative myelopathic symptoms were negatively correlated. A significant correlation was observed between the postoperative spinal cord atrophy and the final myelopathic symptoms. Conclusions. The decrease in the lordotic curvature index and the decrease in the intervertebral range of motion after laminoplasty did not cause neurologic deterioration. In the C4–C5 intervertebral segment with a high incidence of listhesis, the restriction of the C4–C5 range of motion improved the clinical myelopathic symptoms. The radiologic prognostic factors were the postoperative restriction of intervertebral range of motion in preoperatively unstable segments and the anatomic reversibility of spinal cord insult.

Anterior-posterior knee laxity increased by exercise: Quantitative evaluation of physiologic changes

To quantify physiologic changes in anterior-posterior laxity of the normal knee caused acutely by exercise, we evaluated the exercise level and the duration of exercise needed to cause changes in laxity, the magnitude of changes in laxity, and the time needed for laxity to return to the level before exercise, by continuously applying a fixed exercise load. After a 20-minute run at 7 km/hr, anterior laxity with a displacement force of 133 N increased by about one third, and the compliance increased by one half with anterior drawer between 0 and 67 N. These changes were maintained at a similar level during exercise. The levels before exercise were restored gradually over 1 hour after exercise. As the muscle strength showed no changes during exercise, we consider these changes in laxity are not associated with a decrease in muscle strength. Furthermore, since the changes in knee laxity after triathlon (in which the knee is subjected to prolonged excessive exercise) are similar to those after running at 7 km/hr, we believe that the magnitude of changes in laxity after exercise is fixed, regardless of the level of the exercise load. Moreover, the threshold of exercise that causes the maximum change is low.

Bone Mass Changes of Tibial and Vertebral Bones in Young and Adult Rats With Collagen-induced Arthritis

To study the effect of arthritis on bone mass, bone mineral density (BMD) of cancellous and cortical bone in the tibial metaphysis and diaphysis in 2- and 7-month-old rats with collagen-induced arthritis (CIA) was serially measured using peripheral quantitative computed tomography (pQCT). BMD in the fourth lumbar vertebra in 7-month-old CIA rats was also measured by pQCT. The fourth lumbar vertebral body, distal femur, and proximal tibia in 7-month-old CIA rats were analyzed histomorphometrically. Changes in BMD differed between 2-month-old (young) and 7-month-old (adult) CIA rats. Although the BMD for the proximal tibia (2 mm and 5 mm distal from the growth cartilage) in young CIA rats decreased compared with that in control rats, the values exceeded the initial value during the arthritis course. On the other hand, bone loss in adult CIA rats occurred predominantly in the cancellous bone of the periarticular region of the tibia (2 mm distal from the growth cartilage), in which the enhancement of bone resorption and reduced bone formation were observed histomorphometrically. No remarkable changes were demonstrated in BMD or histomorphometrical analysis for the lumbar vertebra during the experimental course. These results suggest that bone loss in adult CIA rats resembles the osteoporosis that develops during the early stage of human rheumatoid arthritis. We conclude that adult CIA rats are more appropriate than young CIA rats as an experimental model of secondary osteoporosis due to rheumatoid arthritis.

Radiological pathogenesis of cervical myelopathy in 60 consecutive patients with cervical ossification of the posterior longitudinal ligament.

Study design: The radiological pathogenetic factors for cervical myelopathy in 60 consecutive patients with cervical ossification of the posterior longitudinal ligament (OPLL) were investigated retrospectively. Objective: To clarify which patients with OPLL will develop cervical myelopathy. Methods: Sixty consecutive patients with OPLL were radiologically assessed comparing the myelopathic patient group (M group, n=41) and the mild or non-myelopathic patient group (non-M group, n=19). Results: The narrowing ratio of the spinal canal in the M group (47.1%) was significantly greater (P=0.026) than that in the non-M group (38.3%). The two groups showed a significant difference (P=0.0016) with regard to the Pavlov ratio (M group, 0.73; non-M group, 0.84). The total range of motion of the cervical spine did not differ between the two groups but the per cent range of motion was significantly greater (P=0.037) in the M group than in the non-M group. Conclusion: This study suggests that factors important in the onset or aggravation of myelopathy are factors related to pathological compression by OPLL, cervical soft disc herniation, developmentally narrow spinal canal, and local or non-proportional hypermobility.

Sacral cyst managed with cyst-subarachnoid shunt : A technical case report

Study Design This report describes the cyst–subarachnoid shunt, a novel surgical treatment, for sacral cysts. Objective To introduce a new surgical technique for sacral cysts. Summary of Background Data There is no consensus on the appropriate treatment for symptomatic sacral cysts. The hydrostatic and pulsatile forces of cerebrospinal fluid are attributed to the growth of the cyst and their becoming symptomatic. Methods The clinical and radiologic features of a 41-year-old man with a symptomatic sacral cyst are detailed. A cyst–subarachnoid shunt was set to equalize the cerebrospinal fluid pressure between the cephalad thecal sac and the cyst. Results Immediately after surgery, the patient had no pain in his left leg and was free of pain at 2 years. Magnetic resonance imaging 1 year after surgery showed a decrease in the size of the cyst. Conclusion Although this is a preliminary study, a cyst–subarachnoid shunt can be a useful alternative for symptomatic sacral cysts.

Clinical features and surgical outcomes of cervical myelopathy in the elderly.

Treatment of cervical myelopathy in elderly patients is controversial. We retrospectively studied 113 patients who had decompression surgery from 1990-2001 to clarify how pre-operative conditions, duration of symptoms, involved levels, surgical outcomes, and complications differ between younger and elderly patients. We also asked whether elderly patients would likely have reasonable outcomes of surgery. The patients were divided into five age groups: Group 1, 36-45 years (12 patients); Group 2, 46-55 years (22 patients); Group 3, 56-65 years (31 patients); Group 4, 66-75 years (32 patients); and Group 5, 76-85 years (16 patients). The duration of symptoms was similar among the five groups. The involved level was more cephalic in the older groups, and the most frequently involved level in patients older than 75 years was C3-C4. Neurologic symptoms were more severe preoperatively and postoperatively in older patients. The recovery ratio also was lower in older patients; however, in Group 5 it was 36.9%, which indicated that patients older than 75 years could regain approximately 40% of their function postoperatively. Decompression surgery can be a reasonable treatment option for cervical myelopathy, even in elderly patients.Level of Evidence: Therapeutic Study, Level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.