Yoshito Katayama

Comparison of surgical outcomes between macro discectomy and micro discectomy for lumbar disc herniation: a prospective randomized study with surgery performed by the same spine surgeon.

Study Design A prospective study was conducted on the surgical procedures for lumbar disc herniation. Objective The objective of this study is to investigate the surgical outcomes of different methods when performed by the same surgeon, using a prospective study. Background Macro discectomy is widely known as a common surgical procedure for lumbar disc herniation, while microdiscectomy in place of Caspar technique (the Caspar method) and microendoscopic discectomy by a posterior approach are reported as less invasive surgical methods for this condition. However, there have not been a significant number of prospective studies conducted to compare different surgical procedures for lumbar disc herniation. Materials and Methods The target of our study was a group of 62 patients (male: 43, female: 19) who underwent surgery by macro discectomy (A group) and 57 patients (male: 33, female: 24) who underwent surgery by microdiscectomy in place of Caspar technique (B group). The mean ages at surgery were 34 (14 to 62) years and 41 (18 to 65) years respectively, and the mean duration of follow-up was 2 years and 8 months (12 months to 4 years). For all patients, the surgery was performed by 1 of the authors. The items investigated were the operation time, amount of bleeding, duration of hospitalization, amount of analgesic agent used after surgery, pre- and postoperative scores based on judgment criteria for treatment of lumbar spine disorders established by the Japanese Orthopaedic Association score, visual analog scales (VAS, 0 to 10) for lumbago before surgery and at discharge, VAS for sciatica before surgery and at discharge, perioperative complications, and cases requiring further surgery. Results There were no significant differences between the 2 surgical procedures in the frequency of use of an analgesic agent after surgery, the pre- and postoperative Japanese Orthopaedic Association scores or postoperative VAS for sciatica. Statistically significant differences were observed in the operation time, amount of bleeding, duration of hospitalization, and postoperative VAS for lumbar pain, but the differences were not large, and may not have been clinically significant. Conclusions For herniotomy for lumbar disc herniation, both macro discectomy and microdiscectomy are appropriate, as long as surgeons have mastery of the procedures.

Segmental pedicle screwing for idiopathic scoliosis using computer-assisted surgery.

Study Design Retrospective clinical study. Objectives To evaluate the accuracy of computer-assisted surgery for idiopathic scoliosis. Summary of Background Data Segmental pedicle screw fixation has been proven to enable enhanced correction of scoliotic deformities. However, both neurovascular and visceral structures are at potential risk from screw misplacement due to pedicle drift. No reports exist on the accuracy and benefits of computer-assisted surgery for pedicle screwing in scoliosis surgery. Methods A total of 40 consecutive patients with idiopathic scoliosis were evaluated. Postoperative computed tomography was assessed for the accuracy of pedicle screw placement in 20 cases treated without a navigation system and 20 cases with a computed tomography-based navigation system. Correlations between registered levels and pedicle perforation were investigated. Results Pedicle violation was observed in 28.0% of the control group and 11.4% of the navigation group, with significant differences. No screw misplacements at the registered levels were seen, and the longer the distance between the registered level and level of screw insertion, the higher the rate of pedicle violation. No intraoperative complications caused by pedicle perforation occurred. Conclusions In the navigation group, a tendency to lateral perforation at the concave side and medial perforation at the convex side was noted, like in the control group. Use of the navigation system significantly reduced the screw misplacement rate for rotated vertebrae as compared with the control group. Separate registration is recommended for rotated vertebrae when possible.

Surgical results of intramedullary spinal cord tumor with spinal cord monitoring to guide extent of resection.

OBJECT The authors investigated the outcome of intramedullary spinal cord tumor surgery, focusing on the effect of preoperative neurological status on postoperative mobility and the extent of tumor excision guided by intraoperative spinal cord monitoring prospectively. METHODS Intramedullary spinal cord tumor surgery was performed in 131 patients between 1997 and 2007. The authors compared the pre- and postoperative neurological status and examined the type of surgery in 106 of these patients. A modified McCormick Scale (Grades I-V) was used to assess ambulatory ability (I = normal ambulation; II = mild motor sensory deficit, independent without external aid; III = independent with external aid; IV = care required; and V = wheelchair required). The type of surgery was classified into 4 levels: total resection, subtotal resection, partial resection, and biopsy. RESULTS The 106 patients consisted of 47 females and 59 males, whose average age was 42.5 years (range 6-75 years). The mean follow-up period was 7.3 years (range 2.5 months-21 years). The tumor types included astrocytoma (12 cases), ependymoma (46 cases), hemangioblastoma (16 cases), cavernous hemangioma (17 cases), and others (15 cases overall: gangliocytoma, 1; germ cell tumor, 1; lymphoma, 3; neurinoma, 1; meningioma, 1; oligodendroglioma, 1; sarcoidosis, 2; glioma, 1; and unknown, 4). Initial total excision, subtotal resection, partial resection, biopsy, and duraplasty were performed in 59, 12, 22, 12, and 1 patients, respectively. According to the preoperative McCormick Scale, ambulatory status was classified as Grades I, II, III, IV, and V in 41(38%), 30 (28%), 14 (13%), 19 (19%), and 2 (2%) patients, respectively. Thirty-three (31%) of 106 patients suffered postoperative neurological deterioration. The number of patients who did not lose ambulatory ability or who achieved an ambulatory status of Grade I or II postoperatively was 33 (80%), 21 (70%), 10 (71%), 8 (42%), and 1 (50%) in patients with preoperative Grades I, II, III, IV, and V, respectively. Total excision was performed in 31 (79%) of 39 patients with preoperative Grade I, 12 (40%) of 30 patients with Grade II, 7 (50%) of 14 patients with Grade III, and 9 of 21 patients (38%) with Grade IV or V, indicating that the rate of total excision was significantly higher in patients with Grade I status. CONCLUSIONS The postoperative ambulatory ability was excellent in patients with a good preoperative neurological status. Total excision in patients with Grade I or II ambulation was associated with a good prognosis for postoperative mobility. However, the rate of postoperative deterioration was 31.5%, which is relatively high, and patients should be fully informed of this concern prior to intramedullary spinal cord tumor surgery.

The effect of autologous fibrin tissue adhesive on postoperative cerebrospinal fluid leak in spinal cord surgery: a randomized controlled trial.

Study Design. A prospective randomized study evaluating the efficacy of autologous fibrin tissue adhesive for decreasing postoperative cerebrospinal fluid (CSF) leak in spinal cord surgery. Objective. To compare postoperative CSF leak in 3 groups (i.e., autologous fibrin tissue adhesive used, commercial fibrin glue used, and no fibrin tissue adhesive used) of patients undergoing spinal surgery who needed dural incision. Summary of Background Data. Spinal cord operations, particularly when dural incision is inevitable, sometimes involve postoperative CSF leak. Because CSF leak is a serious complication, countermeasure is necessary to prevent it after dural suture. Commercial fibrin tissue adhesive was formerly used. Because the possibility of prion infection was widely noticed, commercial fibrin tissue adhesive containing animal components has been used less often. Methods. In 13 of 39 cases in which dural incision would be made, 400 mL whole blood was drawn, and autologous fibrin tissue adhesive was made of plasma. Cases were divided into 3 groups: (1) dural closure alone, (2) use of autologous fibrin tissue adhesive after dural closure, and (3) use of commercial fibrin tissue adhesive after dural closure. The primary outcome measure was determined as postoperative (3 days) volume of drainage fluid, and results were analyzed using the analysis of variance. The secondary outcome measure was general blood test, coagulation assay, and plasma fibrinogen, and these were analyzed also using the analysis of variance. Results. There was a significant difference in the primary outcome between the autologous and control groups. No complications such as infection or continuous CSF leak were observed in any case. The mean volume of drainage fluid was 586.2 mL in the group with autologous fibrin tissue adhesive and 1026.1 mL in the group without fibrin tissue adhesive. The volume of drainage fluid was significantly lower in the former group than that in the latter group. There was no statistical difference between the volumes of the group with autologous adhesive and with commercial adhesive (639.2 mL). Conclusions. We used autologous fibrin tissue adhesive as a new sealant after dural closure instead of commercial fibrin tissue adhesive. No definitive CSF leak was observed, and the volume of drainage fluid was significantly lower in the group with autologous fibrin tissue adhesive than that in the group without fibrin tissue adhesive. The use of autologous fibrin tissue adhesive was superior to that of commercial fibrin tissue adhesive in cost.

The Effect of Muscle Relaxant on the Paraspinal Muscle Blood Flow : A Randomized Controlled Trial in Patients With Chronic Low Back Pain

Study Design. A randomized controlled trial. Objective. To investigate the effect of muscle relaxant for muscle blood flow at the trunk muscle in patients with chronic low back pain (LBP). Summary of Background Data. Paraspinal muscle function is widely believed to play a role and considered to be of etiologic significance in LBP, and intramuscular pressure increases and blood flow decreases in the flexion position. Decrease in oxygenated hemoglobin at the trunk muscle is seen in patients with LBP. Methods. A total of 74 male patients with LBP lasting more than 6 months were randomized to 3 treatment groups: (1) physical therapy only (control) (n = 25), (2) administration of eperisone hydrochloride (EMPP) for 4 weeks (n = 24), and (3) McKenzie therapy (n = 25). The primary outcome variables, observed at 2 and 4 weeks, are the Japanese Orthopedic Association LBP score, visual analogue scale (VAS), Faces Pain Scale-Revised, and SF-36. Intramuscular oxygenation was evaluated using near-infrared spectroscopy during lumbar extension and flexion, and oxygenated hemoglobin and deoxygenated hemoglobin were compared. Results. VAS was significantly lower at 4 weeks in the McKenzie group than in the control group. There were no significant changes at 2 weeks in all parameters, however, the relative change of oxygenated hemoglobin during lumbar extension at 4 weeks was significantly higher in the EMPP group when compared with the other 2 groups. The relative change of deoxygenated hemoglobin during lumbar flexion showed a significant difference at 4 weeks in the EMPP group when compared with the control group. Conclusion. Administration of EMPP for 4 weeks improved the LBP in VAS, though not as effective as McKenzie therapy. Our data demonstrated the effects of eperisone hydrochloride on paraspinal muscle hemodynamics improving intramuscular oxygenation during lumbar extension and flexion in patients with chronic LBP.

Association of gene polymorphisms with intervertebral disc degeneration and vertebral osteophyte formation.

Study Design. Cross-sectional cohort study of elderly people. Objectives. To examine the factors influencing osteophyte formation without lumbar disc degeneration and to estimate the implications of osteophytes from the viewpoint of low back pain and gene polymorphisms. Summary of Background Data. The degenerative changes that occur in the intervertebral discs are the point of departure of osteophyte formation. Several studies on factors associated with genetic susceptibility to spinal osteophyte formation, such as VDR and TGF-β1. However, there are no detailed studies concerning osteophytes not accompanied with disc degeneration. Methods. A total of 387 elderly persons were recruited, and disc degeneration and osteophyte formation were evaluated. The cases with osteophyte formation were classified into 3 groups: osteophyte formation with disc height narrowing (n = 217), osteophyte formation without disc height narrowing (n = 99), and control group defined as the cases without osteophyte formation (n = 71). Twelve genotypes were characterized. Correlations between these degenerative factors and the polymorphisms were analyzed. Results. The prevalence of low back pain was significantly greater in the group of osteophyte formation with disc height narrowing than the other 2 groups. In the polymorphism of alcohol dehydrogenase (ADH2), prevalence of osteophyte formation without disc height narrowing was less in His/Arg (odds ratio = 0.57, P = 0.041) and Arg/Arg (odds ratio = 0.41, P = 0.18) than His/His. Conclusions. Patients with osteophyte formation preceding intervertebral disc narrowing had a lower risk of low back pain compared with those without osteophytes. The 47Arg polymorphism in the ADH2 may act to suppress osteophyte formation unaffected by disc degeneration.

Spinal Myxopapillary Ependymoma : Neurological Deterioration in Patients Treated With Surgery

Study Design. A retrospective multicenter study of series of 20 patients with myxopapillary ependymomas, which underwent surgery. Objective. To evaluate the postoperative outcomes of patients surgically treated for spinal myxopapillary ependymoma. Neurologic deterioration after tumor resection is discussed in terms of the tumor encapsulation. Summary of Background Data. Myxopapillary ependymomas occur most commonly in the cauda equina and/or conus medullaris region. Most series published in the literature have covered postoperative tumor recurrence and role of adjuvant radiotherapy. Few contradistinctive studies in postoperative neurological deficit were reviewed from the standpoints of MRI and histopathologic findings. Methods. A total of 20 patients were recruited and charts, MRI, intraoperative findings, and pathologic findings were reviewed. The follow-up period ranged from 2 to 12 years (median, 72.9 months). The surgical procedures were defined as gross total removal, piecemeal total removal, and subtotal removal. Postoperative radiotherapy was given in 3 patients in whom removal had been subtotal. Results. Gross total removal was achieved in 14 patients, piecemeal gross total and subtotal removal in 3 patients each. Neurologic deterioration after surgery was seen in 5 patients, all of which were unencapsulated tumors consisting of piecemeal gross total removal in 2 patients and subtotal removal in 3 patients. Recovery of postoperative bladder dysfunction remained unchanged in 2 patients. There were no tumor recurrence and progression of the remaining tumors. Unencapsulated tumors were more frequently seen in heterogeneously enhanced tumors on MRI than in homogenously enhanced tumors with significant difference. Conclusion. In the unencapsulated ependymomas, tumor separation and manipulation of the surrounding neural tissue caused neurologic injury. The heterogeneously enhanced ependymoma not only should be evaluated and treated meticulously, but also surgeons should not stick to total removal in infiltrated and adhering tumors as subtotally resected tumors with postoperative radiotherapy have not always recurred.

Surgical complications and management of occipitothoracic fusion for cervical destructive lesions in RA patients.

Study Design Retrospective clinical study. Objective The objective of this study is to evaluate the clinical outcome of occipitothoracic fusion for severe destructive cervical lesions in rheumatoid arthritis (RA) patients with myelopathy and/or occipitocervical pain, and to discuss surgical complications. The complication rates are compared between 2 groups treated with different instrumentation techniques. Summary of Background Data Few studies have reported on the results of occipitothoracic fusion in RA patients. Methods In this study, 56 RA patients with myelopathy and/or occipitocervical pain caused by destructive cervical lesions were studied. The patients were divided into 2 groups A and B, according to the used rod diameter and the application of the cervical pedicle screw system. Group A included 38 patients treated with Unit rods (4.75 mm). Group B included 18 patients treated with cervical pedicle screw system (3.2 mm or 3.5 mm diameter rod). Clinical results and surgical complications were evaluated. Results Mean follow-up time was 36.2 months. Fifteen patients died during follow-up at the mean age of 67.3 years. None died from their cervical lesions. The neurologic status in 46 patients (82%) had improved at least 1 class in the modified Ranawat scale. Perioperative complications occurred in 16 (28.6%), thoracic spine lesions in 11 (19.6%), implant failure in 13 (23.2%), and surgical site infection in 8 (14.3%). There was a tendency for more fractures and pedicle screw pullouts at the lowest level of the fusion area to occur in group B. The neurologic improvement of patients undergoing occipitothoracic fusion after becoming unable to sit owing to their neurologic deficit was poor. Conclusions The current study suggests that occipitothoracic fusion for rheumatoid destructive cervical lesions can be effective in improving neurologic deficit if performed while patients can still sit. Improvements to methodology of this surgery can be made.

A new criterion for the alarm point for compound muscle action potentials.

OBJECT The purpose of this study was to review the present criteria for the compound muscle action potential (CMAP) alert and for safe spinal surgery. METHODS The authors conducted a retrospective study of 295 patients in whom spinal cord monitoring had been performed during spinal surgery. The waveforms observed during spinal surgery were divided into the following 4 grades: Grade 0, normal; Grade 1, amplitude decrease of 50% or more and latency delay of 10% or more; Grade 2, multiphase pattern; and Grade 3, loss of amplitude. Waveform grading, its relationship with postoperative motor deficit, and CMAP sensitivity and specificity were analyzed. Whenever any wave abnormality occurred, the surgeon was notified and the surgical procedures were temporarily suspended. If no improvements were seen, the surgery was terminated. RESULTS Compound muscle action potential wave changes occurred in 38.6% of cases. With Grade 1 or 2 changes, no paresis was detected. Postoperative motor deficits were seen in 8 patients, all with Grade 3 waveform changes. Among the 287 patients without postoperative motor deficits, CMAP changes were not seen in 181, with a specificity of 63%. The false-positive rate was 37% (106 of 287). However, when a Grade 2 change was set as the alarm point, sensitivity was 100% and specificity was 79.4%. The false-positive rate was 20% (59 of 295). CONCLUSIONS Neither the Grade 1 nor the Grade 2 groups included patients who demonstrated a motor deficit. All pareses occurred in cases showing a Grade 3 change. Therefore, the authors propose a Grade 2 change (multiphasic waveform) as a new alarm point. With the application of this criterion, the false-positive rate can be reduced to 20%.

Age-related and Degenerative Changes in the Osseous Anatomy, Alignment, and Range of Motion of the Cervical Spine: A Comparative Study of Radiographic Data From 1016 Patients With Cervical Spondylotic Myelopathy and 1230 Asymptomatic Subjects

Study Design. A prospective comparative study. Objective. This study aimed to establish cervical spine morphometry, alignment, and range of motion (ROM) and to clarify the impact of these age-related and degenerative changes. Summary of Background Data. There are no studies that have evaluated differences in the results of cervical spine radiographs between a large series of cervical spondylotic myelopathy (CSM) patients and healthy subjects. Methods. We enrolled 1016 consecutive CSM patients who underwent laminoplasty. CSM patients were also divided based on each decade of life between the fourth and ninth decades. We also enrolled a total of 1230 healthy volunteers as asymptomatic subjects in this study. There were at least 100 men and 100 women in each decade of life between the third and eighth decades. Cervical sagittal alignment on neutral and flexion-extension views was measured by the Cobb method at C2–7. ROM was assessed by measuring the difference in alignment between flexion and extension. Results. Cervical lordosis in the neutral position increased gradually with age in both groups. CSM patients showed significantly smaller lordotic angles compared with those shown by asymptomatic subjects within each decade. The total ROM decreased with increasing age in both groups. The total ROM of females was larger than males. The ROM of CSM patients was significantly smaller than asymptomatic subjects. The flexion ROM did not change with aging in either group. There was no significant difference in the flexion ROM between males and females in the two groups. However, the extension ROM decreased gradually in both groups. The extension ROM of CSM patients was significantly smaller than asymptomatic subjects. Conclusion. Age-related and degenerative changes in the cervical spine, alignment, and ROM in each decade of life were established between CSM patients and asymptomatic subjects. Level of Evidence: 1