Search Results

You are looking at 1 - 10 of 25 items for

  • Author or Editor: Motoki Iwasaki x
Clear All Modify Search
Restricted access

Kazuhiro Chiba, Itsuo Yamamoto, Hisashi Hirabayashi, Motoki Iwasaki, Hiroshi Goto, Kazuo Yonenobu and Yoshiaki Toyama

Object. Ossification of the posterior longitudinal ligament (OPLL) often progresses after surgery, and this may cause late-onset neurological deterioration. There have been few studies, however, to clarify any correlation between progression and clinical outcome, partly because of the lack of studies involving reliable and reproducible methods by which detection of progression is made possible. The authors conducted a multicenter study to investigate the occurrence of postoperative progression and to elucidate the possible risk factors in a large-scale patient population, and a novel computer-assisted measurement method was used to provide the basis for future clinical studies.

Methods. The authors analyzed lateral plain radiographs obtained immediately and at 1 and 2 years after surgery in 131 patients who underwent posterior decompression at 13 institutions. The x-ray films were transformed via scanner into digital images; the length and thickness of ossifications were measured using a new computer-assisted measurement system, and the incidence of progression was determined. Odds ratios for progression according to age group and types of OPLL were determined and compared to elucidate significant risk factors of progression.

Conclusions. This is the first multicenter study to investigate the incidence of OPLL progression after posterior decompression by using a standardized measurement method. The rate of postoperative progression at 2 years was 56.5%, which was comparable with results reported in other studies. Progression occurred more frequently in younger-age rather than in older-age patient populations at both 1 and 2 years postoperatively. Mixed-type and continuous-type OPLL progressed more frequently than the segmental-type lesion at 2 years. The results of the present study could serve as basis for future studies to assess the efficacy of drug therapy to prevent OPLL progression.

Full access

Shinya Okuda, Takenori Oda, Ryoji Yamasaki, Takafumi Maeno and Motoki Iwasaki

One of the most important sequelae affecting long-term results is adjacent-segment degeneration (ASD) after posterior lumbar interbody fusion (PLIF). Although several reports have described the incidence rate, there have been no reports of repeated ASD. The purpose of this report was to describe 1 case of repeated ASD after PLIF. A 62-year-old woman with L-4 degenerative spondylolisthesis underwent PLIF at L4–5. At the second operation, L3–4 PLIF was performed for L-3 degenerative spondylolisthesis 6 years after the primary operation. At the third operation, L2–3 PLIF was performed for L-2 degenerative spondylolisthesis 1.5 years after the primary operation. Vertebral collapse of L-1 was detected 1 year after the third operation, and the collapse had progressed. At the fourth operation, 3 years after the third operation, vertebral column resection of L-1 and replacement of titanium mesh cages with pedicle screw fixation between T-4 and L-5 was performed. Although the patient's symptoms resolved after each operation, the time between surgeries shortened. The sacral slope decreased gradually although each PLIF achieved local lordosis at the fused segment.

Full access

Tomiya Matsumoto, Shinya Okuda, Takafumi Maeno, Tomoya Yamashita, Ryoji Yamasaki, Tsuyoshi Sugiura and Motoki Iwasaki

OBJECTIVE

The importance of spinopelvic balance and its implications for clinical outcomes after spinal arthrodesis has been reported in recent studies. However, little is known about the relationship between adjacent-segment disease (ASD) after lumbar arthrodesis and spinopelvic alignment. The purpose of this study was to clarify the relationship between spinopelvic radiographic parameters and symptomatic ASD after L4–5 single-level posterior lumbar interbody fusion (PLIF).

METHODS

This was a retrospective 1:5 matched case-control study. Twenty patients who had undergone revision surgery for symptomatic ASD after L4–5 PLIF and had standing radiographs of the whole spine before primary and revision surgeries were enrolled from 2005 to 2012. As a control group, 100 age-, sex-, and pathology-matched patients who had undergone L4–5 PLIF during the same period, had no signs of symptomatic ASD for more than 3 years, and had whole-spine radiographs at preoperation and last follow-up were selected. Mean age at the time of primary surgery was 68.9 years in the ASD group and 66.7 years in the control group. Several radiographic spinopelvic parameters were measured as follows: sagittal vertical axis (SVA), thoracic kyphosis (TK), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), lumbar lordosis (LL), and segmental lordosis at L4–5 (SL) in the sagittal view, and C7–central sacral vertical line (C7-CSVL) in the coronal view. Radiological parameters were compared between the groups.

RESULTS

No significant change was found between pre- and postoperative radiographic parameters in each group. In terms of preoperative radiographic parameters, the ASD group had significantly lower LL (40.7° vs 47.2°, p < 0.01) and significantly higher PT (27° vs 22.9°, p < 0.05) than the control group. SVA ≥ 50 mm was observed in 10 of 20 patients (50%) in the ASD group and in 21 of 100 patients (21%, p < 0.01) in the control group. PI-LL ≥ 10° was noted in 15 of 20 patients (75%) in the ASD group and in 40 of 100 patients (40%, p < 0.01) in the control group on preoperative radiographs. Postoperatively, the ASD group had significantly lower TK (22.5° vs 30.9°, p < 0.01) and lower LL (39.3° vs 48.1°, p < 0.05) than the control group had. PI-LL ≥ 10° was seen in 15 of 20 patients (75%) in the ASD group and in 43 of 100 patients (43%, p < 0.01) in the control group.

CONCLUSIONS

Preoperative global sagittal imbalance (SVA > 50 mm and higher PT), pre- and postoperative lower LL, and PI-LL mismatch were significantly associated with ASD. Therefore, even with a single-level PLIF, appropriate SL and LL should be obtained at surgery to improve spinopelvic sagittal imbalance. The results also suggest that the achievement of the appropriate LL and PI-LL prevents ASD after L4–5 PLIF.

Restricted access

Yasuji Kato, Motoki Iwasaki, Takeshi Fuji, Kazuo Yonenobu and Takahiro Ochi

Object. This retrospective study was performed to assess the long-term results of cervical laminectomy in treating ossification of the posterior longitudinal ligament (OPLL) of the cervical spine.

Methods. The authors reviewed medical records in 44 of 52 patients who underwent cervical laminectomy between 1970 and 1985 (mean follow up 14.1 years). The neurological recovery rate after laminectomy was 44.2% after 1 year and 42.9% after 5 years. The surgical outcome was maintained after 5 years but worsened between 5 and 10 years postsurgery: the recovery rate at the last follow-up review was 32.8%. Using multivariate stepwise analysis, the preoperative factors that affected clinical results were found to be the age at operation, the severity of preexisting myelopathy, and a history of trauma. Late neurological deterioration was observed in 10 (23%) of 44 patients. The earliest deterioration occurred at 1 year and the latest was at 17 years postsurgery (mean 9.5 years). The most frequent cause of deterioration was trauma due to a fall (six patients), followed by ossification of the ligamentum flavum (three patients). Postoperative spread of the OPLL was noted in 70% of the patients, but it was clearly the cause of neurological deterioration in only one of them. After laminectomy, postoperative progression of kyphotic deformity was observed in 47% of patients, but these changes did not cause neurological deterioration.

Conclusions. The authors recommend early surgical decompression for OPLL because the outcome is better for younger patients and for those with a higher score as measured by the Japanese Orthopedic Association's system.

Restricted access

Motoki Iwasaki, Yoshiharu Kawaguchi, Tomoatsu Kimura and Kazuo Yonenobu

Object. The authors report the long-term (more than 10-year) results of cervical laminoplasty for ossification of the posterior longitudinal ligament (OPLL) of the cervical spine as well as the factors affecting long-term postoperative course.

Methods. The authors reviewed data obtained in 92 patients who underwent cervical laminoplasty between 1982 and 1990. Three patients were lost to follow up, 25 patients died within 10 years of surgery, and 64 patients were followed for more than 10 years. Results were assessed using the Japanese Orthopaedic Association (JOA) scoring system for cervical myelopathy. The recovery rate was calculated using the Hirabayashi method. The mean neurological recovery rate during the first 10 years after surgery was 64%, which declined to 60% at the last follow-up examination (mean follow up 12.2 years). Late neurological deterioration occurred in eight patients (14%) from 5 to 15 years after surgery. The most frequent causes of late deterioration were degenerative lumbar disease (three patients), thoracic myelopathy secondary to ossification of the ligamentum flavum (two patients), or postoperative progression of OPLL at the operated level (two patients). Postoperative progression of the ossified lesion was noted in 70% of the patients, but only two patients (3%) were found to have related neurological deterioration. Additional cervical surgery was required in one patient (2%) because of neurological deterioration secondary to progression of the ossified ligament. The authors performed a multivariate stepwise analysis, and found that factors related to better clinical results were younger age at operation and less severe preexisting myelopathy. Younger age at operation, as well as mixed and continuous types of OPLL, was highly predictive of progression of OPLL. Postoperative progression of kyphotic deformity was observed in 8% of the patients, although it did not cause neurological deterioration.

Conclusions. When the incidence of surgery-related complications and the strong possibility of postoperative growth of OPLL are taken into consideration, the authors recommend expansive and extensive laminoplasty for OPLL.

Restricted access

Hiroyuki Aono, Tetsuo Ohwada, Noboru Hosono, Hidekazu Tobimatsu, Kenta Ariga, Takeshi Fuji and Motoki Iwasaki

Object

Neurological deterioration due to spinal epidural hematoma (SEH) is a rare but significant complication of spinal surgery. The frequency of hematoma evacuation after spinal surgery is reportedly 0.1%–3%. The objective of this study was to investigate the symptomatology of SEH and the frequency of evacuation for each surgical procedure after spinal decompression surgery.

Methods

This is a retrospective study of 26 patients who underwent SEH evacuation after spinal decompression surgery between 1986 and 2005. During this period, 6356 spinal decompression surgeries were performed. The factors studied were the frequency of SEH evacuation for each surgical procedure, symptoms, time to SEH evacuation, comorbidities, and neurological recovery.

Results

The frequency of SEH evacuation was 0.41% (26 of 6356) for all operations. The frequency for each surgical procedure was 0% (0 of 1568) in standard lumbar discectomy, 0.50% (8 of 1614) in lumbar laminectomy, 0.67% (8 of 1191) in posterior lumbar interbody fusion, 4.46% (5 of 112) in thoracic laminectomy, 0.44% (4 of 910) in cervical laminoplasty, and 0.21% (1 of 466) in cervical anterior spinal fusion. Nine patients had comorbidities involving hemorrhage. Spinal epidural hematoma evacuation was performed between 4 hours and 8 days after the initial operation. Whereas severe paralysis was observed within 24 hours in most patients undergoing cervical and/or thoracic surgery, half of the patients undergoing lumbar surgery had symptoms of SEH such as leg pain or bladder dysfunction after suction drain removal. The shorter the period to evacuation, the better were the results of neurological recovery.

Conclusions

Postoperative SEH was most frequent after thoracic laminectomy. In cervical and thoracic surgeries, symptoms of SEH were noted within 24 hours, mostly severe paralysis, and almost half of the lumbar surgery patients had symptoms after suction drain removal.

Full access

Junichi Kushioka, Tomoya Yamashita, Shinya Okuda, Takafumi Maeno, Tomiya Matsumoto, Ryoji Yamasaki and Motoki Iwasaki

OBJECTIVE

Tranexamic acid (TXA), a synthetic antifibrinolytic drug, has been reported to reduce blood loss in orthopedic surgery, but there have been few reports of its use in spine surgery. Previous studies included limitations in terms of different TXA dose regimens, different levels and numbers of fused segments, and different surgical techniques. Therefore, the authors decided to strictly limit TXA dose regimens, surgical techniques, and fused segments in this study. There have been no reports of using TXA for prevention of intraoperative and postoperative blood loss in posterior lumbar interbody fusion (PLIF). The purpose of the study was to evaluate the efficacy of high-dose TXA in reducing blood loss and its safety during single-level PLIF.

METHODS

The study was a nonrandomized, case-controlled trial. Sixty consecutive patients underwent single-level PLIF at a single institution. The first 30 patients did not receive TXA. The next 30 patients received 2000 mg of intravenous TXA 15 minutes before the skin incision was performed and received the same dose again 16 hours after the surgery. Intra- and postoperative blood loss was compared between the groups.

RESULTS

There were no statistically significant differences in preoperative parameters of age, sex, body mass index, preoperative diagnosis, or operating time. The TXA group experienced significantly less intraoperative blood loss (mean 253 ml) compared with the control group (mean 415 ml; p < 0.01). The TXA group also had significantly less postoperative blood loss over 40 hours (mean 321 ml) compared with the control group (mean 668 ml; p < 0.01). Total blood loss in the TXA group (mean 574 ml) was significantly lower than in the control group (mean 1080 ml; p < 0.01). From 2 hours to 40 hours, postoperative blood loss in the TXA group was consistently significantly lower. There were no perioperative complications, including thromboembolic events.

CONCLUSIONS

High-dose TXA significantly reduced both intra- and postoperative blood loss without causing any complications during or after single-level PLIF.

Restricted access

Tomoya Yamashita, Hironobu Sakaura, Kazuya Oshima, Motoki Iwasaki and Hideki Yoshikawa

The authors report on the case of a 64-year-old man with solitary intradural extramedullary non-Hodgkin lymphoma of the cervical spine. The lesion mimicked the appearance of meningioma on MR imaging. Positron emission tomography showed increased accumulation of fluorine-18–labeled fluorodeoxyglucose only in the cervical lesion. Serum levels of C-reactive protein and soluble interleukin-2 receptor were mildly elevated. At surgery, the intradural tumor in the subarachnoid space was totally extirpated. Based on histopathological findings, diffuse, large B-cell type non-Hodgkin lymphoma was diagnosed. Postoperatively, the patient was treated with 2 courses of chemotherapy by intrathecal injection of methotrexate, cytarabine, and prednisolone and 4 courses of intravenous rituximab, an antibody binding to CD20 on the surface of B cells. All preoperative symptoms completely resolved after surgery. Two years postoperatively, the patient was faring well with no evidence of local recurrence or new lesions at any other site. To the best of the authors' knowledge, this case is the first reported instance of solitary intradural extramedullary non-Hodgkin lymphoma of the cervical spine.

Full access

Shinya Okuda, Takenori Oda, Ryoji Yamasaki, Takamitsu Haku, Takafumi Maeno and Motoki Iwasaki

Object

The management of isthmic spondylolisthesis remains controversial, especially with respect to reduction. There have been no reports regarding appropriate slip reduction. The purpose of this study was to investigate the following issues: 1) surgical outcomes of posterior lumbar interbody fusion (PLIF) with total facetectomy for low-dysplastic isthmic spondylolisthesis, including postoperative complications; 2) effects of slip reduction on surgical outcomes; and 3) appropriate slip reduction.

Methods

A total of 106 patients who underwent PLIF with total facetectomy for low-dysplastic isthmic spondylolisthesis and who were followed for at least 2 years were reviewed. The average follow-up period was 8 years. Surgical outcomes, including the scores assessed using the Japanese Orthopaedic Association scoring system, the recovery rate, and postoperative complications were investigated. As for radiographic evaluations, pre- and postoperative slip and disc height, instrumentation failure, and fusion status were also examined.

Results

The pre- and postoperative average Japanese Orthopaedic Association scores were 14 (range 3–25) and 25 (range 11–29) points, respectively. The average recovery rate was 73% (range 0%–100%). The average pre- and postoperative slip was 24% and 10%, respectively. A significant correlation between postoperative slip and clinical outcomes was found; clinical outcomes were better in proportion to slip reduction. Although no statistical difference was detected in clinical outcomes between postoperative slip of less than 10% and from 10% to 20%, patients with postoperative slip of more than 20% showed significantly worse clinical outcomes. Postoperative complications included neurological deficits in 7 patients (transient motor loss in 6 and permanent motor loss in 1), instrumentation failures in 7, adjacent-segment degeneration in 5, and nonunion in 4. Instrumentation failures occurred significantly more often in patients with more slip reduction, although slip reduction did not affect the other postoperative complications. All patients with instrumentation failure showed postoperative slip reduction within 10%.

Conclusions

The use of PLIF with total facetectomy for low-dysplastic isthmic spondylolisthesis appears to produce satisfactory clinical outcomes, with an average of 73% recovery rate and few postoperative complications. Although clinical outcomes were better in proportion to slip reduction, excessive reduction caused instrumentation failure, and patients with less reduction demonstrated worse clinical outcomes. Appropriate reduction resulted in a postoperative slip ranging from 10% to 20%.

Restricted access

Shinya Okuda, Akira Miyauchi, Takenori Oda, Takamitsu Haku, Tomio Yamamoto and Motoki Iwasaki

Object

Previous studies of surgical complications associated with posterior lumbar interbody fusion (PLIF) are of limited value due to intrastudy variation in instrumentation and fusion techniques. The purpose of the present study was to examine rates of intraoperative and postoperative complications of PLIF using a large number of cases with uniform instrumentation and a uniform fusion technique.

Methods

The authors reviewed the hospital records of 251 patients who underwent PLIF for degenerative lumbar disorders between 1996 and 2002 and who could be followed for at least 2 years. Intraoperative, early postoperative, and late postoperative complications were investigated.

Intraoperative complications occurred in 26 patients: dural tearing in 19 patients and pedicle screw malposition in seven patients. Intraoperative complications did not affect the postoperative clinical results. Early postoperative complications occurred in 19 patients: brain infarction occurred in one, infection in one, and neurological complications in 17. Of the 17 patients with neurological complications, nine showed severe motor loss such as foot drop; the remaining eight patients showed slight motor loss or radicular pain alone, and their symptoms improved within 6 weeks. Late postoperative complications occurred in 17 patients: hardware failure in three, nonunion in three, and adjacent-segment degeneration in 11. Postoperative progression of symptomatic adjacentsegment degeneration was defined as a condition that required additional surgery to treat neurological deterioration.

Conclusions

The most serious complications of PLIF were postoperative severe neurological deficits and adjacent-segment degeneration. Prevention and management of such complications are necessary to attain good long-term clinical results.