Hitoshi Hase

Is posterior spinal cord shifting by extensive posterior decompression clinically significant for multisegmental cervical spondylotic myelopathy

Study Design. Posterior cervical spinal cord shifting after selective single laminectomy associated with partial laminotomies was compared with that after bilateral open-door laminoplasty between the C3 and C7 levels in relation to the clinical results of each procedure. Objectives. To investigate the clinical significance of posterior spinal cord shifting after extensive cervical laminoplasty. Summary of Background Data. Current techniques used for cervical laminoplasty for multisegmental cervical spondylotic myelopathy (CSM) are consecutively performed between the C3 and C6 or C7 levels with expectation that the spinal cord will shift backward to keep it clear of anterior compression. However, the clinical significance of the posterior spinal cord shifting remains controversial, and there has been no report verifying it by comparing limited posterior decompression procedures with conventional extensive ones. Methods. Twenty-six patients with consecutive 2- to 3-level CSM who underwent selective laminoplasty (Group A) were enrolled in the study, and among 56 CSM patients who underwent bilateral open-door laminoplasty between the C3 and C7 levels, 25 who had consecutive 2- or 3- level stenosis identified by preoperative magnetic resonance imaging were used as controls (Group B). The recovery rate was calculated using preoperative and postoperative Japanese Orthopedic Association (JOA) scores for each patient, and for each patient’s magnetic resonance imaging, the postoperative cervical curvature index was obtained according to Ishihara’s method and the magnitude of postoperative backward shifting of the spinal cord was measured. Results. There was no significant difference between the subjects in Groups A and B with respect to the spinal curvature index, preoperative JOA scores, and recovery rate, but the magnitude of the postoperative posterior shifting of the spinal cord was greater for those in Group B than for those in Group A. There was no correlation between the recovery rate and posterior shifting of the spinal cord for each group, and no correlation was also found between the curvature index and posterior shifting of the spinal cord. Conclusions. The outcome of posterior decompression surgery for multisegmental CSM is not correlated with the magnitude of postoperative backward shifting of the spinal cord. Extensive and consecutive decompression performed in conventional cervical laminoplasties is therefore not always necessary for multisegmental CSM.

Classification of vertebral compression fractures in the osteoporotic spine

Objective: The purpose of this study was to clarify the relationship between initial radiographs of osteoporotic vertebral compression fractures (VCFs) and clinical results. Methods: Of the 135 VCFs in the elderly, 73 consecutive patients (84 vertebrae) were reviewed retrospectively. All patients were treated without rigid immobilization. The subjects consisted of 15 men and 58 women. The mean age was 75.0 years with a range from 61 to 91 years. The early radiographic features were classified into five types based on lateral radiographs. Radiographic results during follow-up were evaluated according to the number of collapsed vertebrae and vacuum clefts. Clinical results were evaluated by Visual Analog Scale and activities of daily living. Results: Of the five types, swelled-front-type, bow-shaped-type, and projecting-type fractures had a poor prognosis with late collapse and often showing a vacuum cleft. On the other hand, concave-type and dented-type fractures had a good prognosis and almost achieved fusion. Clinical results of 28 patients with vacuum clefts were fair at the final follow-up. Nineteen patients had little back pain, and nine patients experienced moderate back pain. Regarding the activities of daily living, four patients had difficulty walking.

Muscle-preserving interlaminar decompression for the lumbar spine: a minimally invasive new procedure for lumbar spinal canal stenosis.

Study Design. Outcomes of muscle-preserving interlaminar decompression (MILD) for the lumbar spine are reported. Objective. To verify the clinical findings of lumbar MILD. Summary of Background Data. A preliminary short-term follow-up study of lumbar MILD demonstrated satisfactory neural recovery and reduced invasiveness. Methods. The initial 105 consecutive patients with lumbar spinal canal stenosis were included in this study. A total of 210 intervertebral levels were decompressed. There were 48 women and 57 men, and the mean patient age was 68.8 years. The postoperative follow-up period ranged from 8 to 44 months (mean 21.3months). Eighty-one patients showed cauda equina claudication, and 75 patients complained of radicular pain. Preoperative imaging studies demonstrated that all patients had moderate-to-severe spinal canal stenosis, 75 patients had degenerative spinal canal stenosis, and the remaining 30 had degenerative spondylolisthesis. Pre- and postoperative Japanese Orthopedic Association scores, intraoperative blood loss, surgical complications, and postoperative ambulation were recorded. Results. One hundred five patients underwent lumbar MILD procedure for 210 interspinous levels, 42 patients for 2 levels, 37 patients for 1 level, 17 for 3 levels, 7 for 4 levels, and 2 for 5 levels. Cerebrospinal fluid leakage due to dural tear occurred in 2 patients. Expansion of the operative field was not necessary to repair the dura mater. The mean operation time was 104.9 minutes per level, and mean intraoperative blood loss was 29.4 g per level. Neurologic improvement was demonstrated in all patients. The mean recovery rate calculated with pre- and postoperative Japanese Orthopedic Association scores was 64.9%. Patients started to stand or walk an average of 2.5 days after surgery. None of the patients presented with wound infection. There was no neurologic complication in this series. Conclusion. In MILD for the lumbar spine, damage to the posterior stabilizing structures such as the intervertebral facet joints, paravertebral muscles, thoracolumbar fascia, supra- and interspinous ligaments, can be minimized, while preserving the function of the spinous processes as lever arms for lumbar extension.

Atlantoaxial subluxation in different intraoperative head positions in patients with rheumatoid arthritis

Background: Disorders of the cervical spine are often observed in patients with rheumatoid arthritis (RA). However, the best head position for RA patients with atlantoaxial subluxation in the perioperative period is unknown. This study investigated head position during general anesthesia for the patients with RA and proven atlantoaxial subluxation. Methods: During anesthesia of patients with RA and proven atlantoaxial subluxation, the authors used fluoroscopy to obtain a lateral view of the upper cervical spine in four different positions: the mask position, the intubation position, the flat pillow position, and the protrusion position. Copies of the still fluoroscopic images were used to determine the anterior atlantodental interval, the posterior atlantodental interval, and the angle of atlas and axis (C1–C2 angle). Results: The anterior atlantodental interval was significantly smaller in the protrusion position (2.3 mm) than in the flat pillow position (5.1 mm) (P < 0.05). The posterior atlantodental interval was significantly greater in the protrusion position (18.9 mm) than in the flat pillow position (16.2 mm) (P < 0.05). The C1–C2 angle was, on average, 9.3° greater in the protrusion position than in the flat pillow position (P < 0.05). Conclusion: This study showed that the protrusion position using a flat pillow and a donut-shaped pillow during general anesthesia reduced the anterior atlantodental interval and increased the posterior atlantodental interval in RA patients with atlantoaxial subluxation. This suggests that the protrusion position, which involves support of the upper cervical spine and extension at the craniocervical junction, might be advantageous for these patients.

Septic Arthritis of a Lumbar Facet Joint Associated with Epidural and Paraspinal Abscess

CASE REPORT A 59-year-old woman presented to our clinic two days after experiencing an onset of severe low back pain. There was no prior trauma or other known causal factor. The initial medical examination revealed no neurological abnormalities except for tenderness in her right lumbar region and a positive right Kemp sign. The patient had not developed a fever. Despite taking anti-inflammatory drugs, her low back pain continued. She was admitted 2 days after her initial visit. She had no history of spinal injections or history of diabetes mellitus. Her blood test showed that the inflammatory signs were high, the leukocyte count was 12.200/mm3 (normal range: 4.5008.500/mm3), the erythrocyte sedimentation rate was 84 mm/hr (normal: 3-15 mm/hr) and the C-reactive protein was 5.3 mg/dL (normal: 0.6 mg/dL). Plain radiographs showed no abnormal lumbar vertebrae or facet joint. A T1-weighted sagittal magnetic resonance imaging (MRI) revealed a cystic lesion on the posterior side of the spinal canal at the L2-L3 level (Figure 1). The cystic lesion showed high-signal intensity on T2-weighted axial MRI and it was observed in the epidural and paraspinal regions, communicating with the right L2-L3 facet joint (Figure 2). T1-weighted gadolinium-enhanced contrast was also noted with this lesion. There was no evidence of infection in the vertebral body or disk (Figure 3). Computed tomography scans showed swollen right paraspinal muscles, but no clear damage of the facet joint was observed. The patient’s temperature remained normal, but her C-reactive protein level increased to as high as 19.5 mg/dL 4 days after admission, and she was diagnosed as having septic arthritis of the lumbar facet joint associated with epidural and paraspinal abscess. After intravenous piperacillin sodium administration, the C-reactive protein level temporarily decreased, but her pain worsened. Three weeks later, she still had a fever that reached 38°C. Although no blood cultures showed growth, after continuous intravenous administration of sulbactam sodium/cefoperazon sodium, cefmetazole sodium, and imipenem/cilastatin sodium, her pain became intolerable; therefore, irrigation and debridement were performed 35 days after initial admission to our hospital. The L1-L3 was approached posteriorly and an abcess was noted under the multifidus muscle. The necrotic muscle was removed. The articular capsule and cartilage of the right L2L3 facet joint were debrided. An L1-L3 laminectomy was performed to drain the epidural abscess. Intraoperative cultures revealed no growth. After surgery, the low back pain resolved, and the patient did not report any recurrence at 18-month final follow-up.

Complete anterior fracture-dislocation of the fourth lumbar vertebra.

This report presents an extremely rare complete anterior fracture dislocation of L4 with incomplete paraplegia and its subsequent treatment, which resulted in anatomical reduction, excellent neurologic recovery, and solid bony fusion

Three-dimensional morphology and kinematics of the craniovertebral junction in rheumatoid arthritis.

Study Design. A case-series study. Objectives. To measure the 3-dimensional (3D) morphology and kinematics of the craniovertebral junction (CVJ) using a 3D computed tomography (CT) model; to reveal abnormal patterns and the relationships between pathology and kinematics. Summary of Background Data. Evaluations using radiography, 2-dimensional (2D) CT and magnetic resonance imaging have limitations because of the complex 3D structure of the CVJ. Methods. Twenty-four rheumatoid arthritis patients (21 females, 3 males) with cervical involvement underwent CT scanning of the cervical spine from the basilar process of the occipital bone to the first thoracic vertebra in neutral and flexed positions. The 3D morphology of the occipital condyle, atlas, and axis were classified based on the type of deformity observed. Periodontoid lesions (continuous bony lesions between the atlas and the odontoid process) were also noted. The 3D kinematics in the atlanto-occipital and atlantoaxial joints were evaluated using the volume merge method. Results. Deformities in the atlanto-occipital joints appeared more frequently than those in the atlantoaxial joints. The most common instability pattern was flexural rotation during flexion at the CVJ. The direction of translational motions during flexion was posterior in the atlanto-occipital joint and anterior and caudal in the atlantoaxial joint. Conclusion. The results suggest that bilateral occipital condyle deformation, unilateral and bilateral mass collapse, and periodontoid lesions may affect flexion/extension rotational instability in the atlantoaxial joint. In addition, unilateral occipital condyle deformation and atlantoaxial joint stability may affect sagittal translational instability to the posterior side in the atlanto-occipital joint. The noninvasive 3D CT imaging technique employed here would be useful for predicting the prognosis of patients with rheumatoid deformities at the CVJ.

The clinical usefulness of preoperative dynamic MRI to select decompression levels for cervical spondylotic myelopathy.

The study subjects included 54 patients with cervical spondylotic myelopathy who underwent a selective laminoplasty. The patients were divided into three groups according to the number of decompressed levels: two levels, three levels and four or five levels. The number of cord compressions at every intervertebral level was determined in the flexion, neutral, and extension position using a dynamic magnetic resonance imaging (MRI) scan in consideration of both static and dynamic compressions. For each group, the clinical outcomes were evaluated. Moreover, the patients were divided into two groups according to their age. Then, the appearance ratios of cord compression between the neutral and extension position were compared at each intervertebral level. The clinical outcomes were satisfactory. There were no statistical differences among the three groups, except for the age and operation time. The position of the neck influenced the number of cord compressions. The appearance ratios of cord compression, which were especially prominent at C2/3, C3/4 and C4/5, showed high scores in the aged. The preoperative dynamic MRI scan was clinically useful. In the aged, attention should be given to C2/3, C3/4 and C4/5.

Evaluation of lumbosacral nerve root lesions using evoked potentials recorded by a surface electrode technique.

Study Design Patients with lumbar disc herniation were studied with lumbosacral evoked potentials (EPs). Objectives. To evaluate lumbosacral EPs for the functional diagnosis of nerve root lesions in patients with lumbar disc herniation. Summary of Background Data. No clinical studies have been conducted using lumbosacral EPs elicited by body surface leads. Methods. Lumbosacral EPs elicited by stimulating the posterior tibial nerve were recorded using surface electrodes placed over the interspinous processes of T12-S1. By subtracting the waveform recorded at NT12 (T12/L1 potential) from that at NL3 (L3/L4 potential), NL3′ (residual potential) potentials were clearly identified. NT12 and NL3′ potentials were classified into four groups based on the degree of the reduction of amplitude and/or the prolongation of latency. Results. Significant correlations were found between the NL3′ score and the straight-leg raising test score (r = 0.36, P < 0.05) and between the NT12 amplitude and sensory disturbance (r = 0.37, P < 0.02). The NL3′ score was 1.2 ± 0.5 points before surgery, and it significantly improved to 2.5 ± 0.5 points 2 months after surgery (P < 0.05). Short-term, the NT12 amplitude did not change significantly. Twelve months after surgery, the NT12 amplitude improved significantly to 1.1 ± 0.5 &mgr;V (P < 0.05). Conclusions. The results of this study indicated that the NL3′ score may reflect impairment of the impulse traversing the nerve root in the acute clinical stage, whereas the NT12 amplitude reflects a neurologic deficit. The postoperative clinical course can be estimated by observing recovery of the NL3′ score and NT12 amplitude.

Radiological grading of cervical destructive spondyloarthropathy in long-term hemodialysis patients.

On the basis of the radiological findings of dialysis patients, we made a radiological grading and analyzed the progression of destructive spondyloarthropathy (DSA) using this grading system. In this system, the radiological features of the vertebral endplates and intervertebral disc spaces were divided into 4 grades (grade 0 to grade III). Grades II and III were defined as DSA. In this study, out of the 787 dialysis patients (447 men and 340 women, mean age: 60.0 years) examined, 133 patients (16.9%) were diagnosed with DSA. During 7 years follow-up, 108 dialysis patients were examined to investigate the clinical characteristics of DSA. Fifteen of 90 non-DSA cases progressed to DSA. Six of 18 DSA cases showed grade progression. The duration required for progression of each grade was analyzed. A new classification of DSA, namely, degenerative DSA and classical DSA, was applied in this study. The degenerative DSA showed faster grade progression than the classical DSA. Therefore, great attention should be paid in the radiological follow-up of elderly patients with grade I who start dialysis at an old age.