Tokuhide Moriyama

C-5 palsy after cervical laminoplasty with instrumented posterior fusion

OBJECT Postoperative C-5 palsy is known as a common complication after cervical laminoplasty. The authors of this article have encountered postoperative C-5 palsy more often when laminoplasty was combined with instrumented posterior spinal fusion than when it was performed alone. The purpose of this clinical study was to examine the incidence of fifth cervical nerve root palsy (C-5 palsy) and surgical results in patients with cervical myelopathy who had undergone laminoplasty with or without instrumented spinal fusion. METHODS The authors retrospectively studied patients with cervical myelopathy who had undergone laminoplasty with or without instrumented posterior spinal fusion. RESULTS Clinical data on 58 patients were evaluated and analyzed. Preoperative diagnoses were cervical spondylotic myelopathy or ossification of the posterior longitudinal ligament of the cervical spine. Twenty-four patients with spondylolisthesis or kyphosis underwent laminoplasty combined with posterior spinal fusion using instrumented lateral mass fixation (fusion group), while the remaining 34 patients underwent laminoplasty without posterior spinal fusion (no-fusion group). In the fusion group, C-5 palsy developed in 6 patients; in the no-fusion group, it occurred in only 1 patient. There was a significant difference in the rate of this complication between the 2 groups. In the fusion group, local kyphosis and spondylolisthesis level were reduced at the fusion level, and all patients with C-5 palsy underwent C4-5 spinal fusion. CONCLUSIONS The incidence of postoperative C-5 palsy is significantly higher after laminoplasty when it is combined with spinal fusion. Correction of kyphosis and spondylolisthesis using posterior instrumentation may be a risk factor for iatrogenic intervertebral foraminal stenosis leading to C-5 palsy.

Comparison of clinical features and outcomes of staphylococcus aureus vertebral osteomyelitis caused by methicillin-resistant and methicillin-sensitive strains

The causative organism of vertebral osteomyelitis (VO) was almost exclusively Staphylococcus aureus. The purpose of this study was to delineate the differences in clinical features and outcomes between patients with methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) VO. This study retrospectively reviewed 85 consecutive patients with VO treated between 2005 and 2011. Surgical site infections were excluded. Diagnosis was made by cultures of either blood or biopsied samples. We identified 16 cases of MRSA VO and 14 cases of MSSA VO. The average follow-up period was 18.5 months. Clinical features and outcomes were analyzed. Males were more likely to have MRSA VO than MSSA VO (87.5% vs. 35.7%). In regards to the number of co-morbidities, patients with MRSA VO had significantly more co-mobidities than patients with MSSA VO. Additionally, the rate of patients who underwent surgical procedure (excluding spinal surgeries in the affected region) within 3 months were significantly higher in the MRSA VO group than the MSSA VO group (56.3% vs. 14.3%). White blood cell counts and C-reactive protein levels in patients with both strains significantly improved 4 weeks after the initial treatment compared with the pretreatment values. The recurrence rate within 6 months tended to be higher for MRSA VO (37.5% vs. 7.1%), but no significant difference in mortality was observed between the two VO types. In conclusion, male sex, multiple co-morbidities and previous non-spine surgery were significant risk factors for VO due to MRSA as compared to MSSA. The recurrence rate within 6 months tended to be higher for MRSA VO. Patients with MRSA VO should be monitored carefully for recurrence by sequential clinical, radiographic, and laboratory examinations during the treatment course.

Risk factors for intraoperative lateral mass fracture of lateral mass screw fixation in the subaxial cervical spine

OBJECT Although lateral mass screw fixation for the cervical spine is a safe technique, lateral mass fracture during screw fixation is occasionally encountered intraoperatively. This event is regarded as a minor complication; however, it poses difficulties in management that may affect fixation stability and clinical outcome. The purpose of this study is to determine the incidence and etiology of lateral mass fractures during cervical lateral mass screw fixation. METHODS A retrospective clinical review of patient records was performed in 117 consecutive patients (mean age 57 years, range 15-86 years) who underwent lateral mass screw fixation using a modified Magerl method from 1997 to 2010 at a single institution. A total of 555 lateral masses were included in this study. The outer diameters of the screws were 3.5 or 4.0 mm. In the retrospective clinical analysis, the incidence of intraoperative lateral mass fractures was reviewed. Potential risk factors for this complication were assessed using multivariate analysis. RESULTS The incidence of lateral mass fractures during cervical lateral mass screw fixation was 4.7% (26 lateral masses) among all cases. Among the disorders, the incidence was highest in patients with destructive spondyloarthropathy (DSA) (18.8%, 12 lateral masses). There was no significant difference with respect to lateral mass fracture between the use of 4.0-mm screws (5.6%) and 3.5-mm screws (3.6%). Independent risk factors identified by logistic regression were DSA (OR 7.89, p < 0.001) and screw insertion in the C-6 lateral masses (OR 2.80, p = 0.018). CONCLUSIONS The overall incidence of lateral mass fracture during cervical lateral mass screw fixation was 4.7%. Destructive spondyloarthropathy as an underlying cause of morbidity and screw placement in the C-6 lateral mass were identified as independent risk factors. Use of a 4.0-mm screw in patients with DSA may be a principal risk factor for this complication.

Postoperative spinal cord herniation with pseudomeningocele in the cervical spine: a case report

BACKGROUND CONTEXT Postoperative spinal cord herniation with pseudomeningocele is a rare disease, with only five cases reported before the present study. PURPOSE To describe the clinical features and radiologic findings of postoperative spinal cord herniation with pseudomeningocele. STUDY DESIGN Case report. METHODS A case of a 51-year-old man who suffered from postoperative spinal cord herniation with pseudomeningocele was reported, and previous reports on this subject are reviewed. RESULTS He had undergone excision of a spinal cord tumor in the cervical spine 10 years previously. He had progressive paraparesis and urinary disturbance 10 years later. The Computed Tomography Multi Planner Reconstruction myelogram showed dilation of the ventral subarachnoid space with left deviation of the spinal cord into the pseudomeningocele at C7. On observation at surgery, the spinal cord appeared displaced dorsally and herniated through the defect of the dorsal dura mater. The spinal cord was tightly adhesive around the dural defect. We released the adhesion of the spinal cord and the dural defect under the spinal cord, and the dural defect was repaired using an artificial dura mater. CONCLUSIONS The release of adhesion around dural defect and repair of dural defect under spinal cord monitoring resulted in a satisfactory neurologic recovery. Surgical repair of the dural defect with a dural substitute was necessary.

Subarachnoid-subarachnoid bypass for spinal adhesive arachnoiditis

The authors report a case of adhesive arachnoiditis (AA) and arachnoid cyst successfully treated by subarachnoid to subarachnoid bypass (S-S bypass). Arachnoid cysts or syringes sometimes compress the spinal cord and cause compressive myelopathy that requires surgical treatment. However, surgical treatment for AA is challenging. A 57-year-old woman developed leg pain and gait disturbance. A dorsal arachnoid cyst compressed the spinal cord at T7-9, the spinal cord was swollen, and a small syrinx was present at T9-10. An S-S bypass was performed from T6-7 to T11-12. The patients gait disturbance resolved immediately after surgery. Two years later, a small arachnoid cyst developed. However, there was no neurological deterioration. The myelopathy associated with thoracic spinal AA, subarachnoid cyst, and syrinx improved after S-S bypass.

Prognosis and adjacent segment disease after lumbar spinal fusion surgery for destructive spondyloarthropathy in long-term hemodialysis patients

BACKGROUND Lumbar destructive spondyloarthropathy (DSA) is a serious complication in long-term hemodialysis patients. There have not been many reports regarding the surgical management for lumbar DSA. In addition, the adjacent segment pathology after lumbar fusion surgery for DSA is unclear. The objective of this study was to assess the clinical outcome and occurrence of adjacent segmental disease (ASD) after lumbar instrumented fusion surgery for DSA in long-term hemodialysis patients. MATERIALS AND METHODS A consecutive series of 36 long-term hemodialysis patients who underwent lumbar instrumented fusion surgery for DSA were included in this study. The mean age at surgery was 65 years. The mean follow-up period was 4 years. Symptomatic ASD was defined as symptomatic spinal stenosis or back pain with radiographic ASD. The Japanese Orthopedic Association score (JOA score), recovery rate (Hirabayashi method), complications, and reoperation were reviewed. RESULTS The mean JOA score significantly increased from 13.5 before surgery to 21.3 at the final follow-up. The mean recovery rate was 51.4%. Six of the 36 patients died within 1 year after index surgery. One patient died due to perioperative complication. Symptomatic ASD occurred in 43% (13 of 30) of the cases. Of these 13 cases, 5 had adjacent segment disc degeneration and 8 had adjacent segment spinal stenosis. Three cases (10%) required reoperation due to proximal ASD. Multi-level fusion surgery increased the risk of ASD compared with single-level fusion surgery (59% vs. 23%). The recovery rate was significantly lower in the ASD group than the non-ASD group (38% vs. 61%). DISCUSSION This study demonstrated that symptomatic ASD occurred in 43% of patients after surgery for lumbar DSA. A high mortality rate and complication rate were observed in long-term hemodialysis patients. Therefore, care should be taken for preoperative planning for surgical management of DSA.

Central pain in patients with Parkinson disease evaluated by pain-related evoked potentials

Pain is a well-recognized nonmotor manifestation of Parkinson disease (PD). This might be related to not only peripheral factors but also abnormal processing of nociceptive input in the central nervous system (CNS). To investigate possible dysfunction of pain pathway or of the processing of pain input in the CNS, we recorded pain-related evoked potentials induced by intra-epidermal electrical stimulation in patients with PD. Pain-related evoked potentials were recorded in 13 patients with PD and 21 healthy controls. The evoked potentials were recorded from the Cz electrode by intra-epidermal electrical stimulation, which is known to selectively stimulate A delta fibers, at the second digit on each of the 4 limbs. The amplitudes between N1 and P1, which are thought to originate from the cingulate cortex and the insula, were significantly lower in patients with PD compared with controls. Patients with PD showed no significant correlation between the severity of clinical parameters, such as Unified Parkinsons Disease Rating Scale or Hoehn and Yahr score, and the amplitudes between N1 and P1. In addition, no differences were found in mean N1 or P1 latency between the two groups. These results may reflect the existence of abnormal central processing of pain inputs in PD, which appears to be independent of the clinical expression of motor dysfunction.

Pain-Related Evoked Potentials in Normal subjects and Patients with persistent pain after spinal surgery

Our final purpose is to investigate the pathway of pain in patient with persistent pain after spinal surgery. This time we recorded a pain related potential for normal subjects and patients with persistent pain after spinal surgery stimulating skin surface electrode Inui developed. Target is 21 normal subjects and 6 patients with persistent pain after spinal surgery. We stimulated index finger and second toe at random using intra epidermal electrical stimulation. The evoked potentials were recorded from Cz. During the patients, we recorded from 16 painful legs. In normal subjects, the latency of upper leg stimulation is significantly faster than that of lower leg stimulation. And there was not significant difference in N1 and P1 latency of upper, lower leg between patients and normal subjects. But the N1 and P1 amplitude in patient with persistent pain after spinal surgery decreased compared with normal subjects. There is possibility of this potential contributing to activity of temporal lobe and cingulate gyrus, ability of calculation for pain and emotion.

4. CMAP derived from proximal and distal muscle by stimulating Erb point and CMCT in cervical spondylotic amyotrophy

The usefulness of the electrophysiological tests on the differentiation of the affected regions (either the nerve root or the anterior horn of the spinal cord) of cervical spondylotic amyotrophy (CSA) was examined on 14 patients with proximal type and 3 patients with distal type CSA. The compound muscle action potentials (CMAP) stimulated at supramaximal Erb point were recorded from the proximal (deltoid and biceps) and distal muscles (extensor digitorum and abductor digiti minimi), and central motor conduction time (CMCT) was calculated from motor evoked potentials and F wave. CMAP was correlated with the manual muscle testing. In distal type CSA patients, decrease in CMAP was observed from both of the distal and the proximal muscles. The delayed CMCT and F wave abnormalities, which suggests the anterior horn legions, were found in 5 proximal and all distal type CSA patients. Furthermore 4 patients with poor prognosis out of 8 operated cases showed the delayed CMCT. Thus, these electrophysiological tests appear to be useful not only to differentiate the affected regions in CSA patients but to predict the prognosis after operation.

P30.47 Electrophysical diagnosis of spinal function in patients with cervical myelopathy using MEP and SEP

KC. Moving the average area backward and forward by two segments from the onset of KCs, 43 traces of BAEPs were calculated (‘B26’, 3.0 ± 0.4 s; . . . ‘onset’, 0.4 ± 0.4 s; ‘A16’, 1.2 ± 0.4 s), each separated by 0.1 s. EEG trends were subtracted by fitting a polynomial curve before the average (160 points). Amplitudes of wave-III and -V were measured and normalized in each case, then temporal changes of the parameters were tested by oneway ANOVA. Results: Wave-III amplitude showed a triphasic change (inactivation–activation–inactivation) preand during KCs (F = 1.96, p < 0.01; from ’B21’ to ’A7’). Wave-V amplitude showed a biphasic change (inactivation–sustained activation; F = 1.56, p < 0.05; from ’B26’ to ’A9’). Conclusion: The results suggest that, in humans, KCs are triggered by a transient but sustained activation of the brainstem.