Kimiaki Sato

Incidence of complications associated with spinal endoscopic surgery: nationwide survey in 2007 by the Committee on Spinal Endoscopic Surgical Skill Qualification of Japanese Orthopaedic Association

BackgroundThis report was conducted to elucidate the current status of spinal endoscopic surgery and relevant incidents through analysis of the results of a questionnaire survey conducted in 2007 by the Committee on Spinal Endoscopic Surgical Skill Qualification of the Japanese Orthopaedic Association (JOA).MethodsQuestionnaire forms were sent to 2011 training facilities nationwide certified by the JOA, and 1082 of these facilities returned the filled questionnaires (response rate 53.8%). Of these facilities, 257 (23.8% of the responding facilities) undertook spinal endoscopic surgery in 2007. These institutions were asked to fill in the survey form with the details of the operations and relevant incidents as well as the incident levels.ResultsIn total, the 257 facilities performed 6239 spinal endoscopic surgeries during 2007. Posterior spinal endoscopic surgery constituted most of the operations (6217 cases, 98.2%) including 4336 cases of microendoscopic discectomy (MED), 1273 cases of microendoscopic laminectomy or fenestration, and 379 cases of transforaminal or posterior lumbar interbody fusion. The total number of incidents was 133 (2.13%). The numbers of incidents by operative method were 75 (56.4%) during MED, 57 (42.9%) during microendoscopic laminectomy or fenestration, and 1 (0.8%) during interbody fusion. Of 133 incidents, dural tear occurred in 99 (74.4%), injury of the cauda equina or a nerve root in 7 (5.3%), facet fracture in 7 (5.3%), hematoma and wrong level in 6 each (4.5%), and wrong side and bedsore in 1 each (0.8%). The incident level was level 1 in 6, level 2 in 24, level 3a in 82, level 3b in 16, level 4 in 5, and level 5 (fatal) in 0.ConclusionsThe results of this survey revealed an increasing trend of spinal endoscopic surgery and a decreasing trend of the complication rates. The complication rates of spinal endoscopic surgery were not higher than those of conventional surgery, indicating the safety of this surgical method.

Intradiscal pressure after repeat intradiscal injection of hypertonic saline: an experimental study

Abstract. Chemonucleolysis with chymopapain is an effective alternative to an operation for the treatment of some patients who have a lumbar intervertebral disc herniation. However, chymopapain is associated with rare but serious complications. Accordingly, alternative substances for chemonucleolysis have been sought. The main beneficial effect of chemonucleolysis derives from the decrease in the intradiscal pressure. We have previously reported that hypertonic saline injected into the intervertebral discs decreased the intradiscal pressure, but only temporarily. The present experimental study investigated changes in the intradiscal pressure after a repeat intradiscal injection of hypertonic saline. The lumbar intervertebral discs of 18 living rabbits were examined: 10% hypertonic saline was injected intradiscally just once in 12 rabbits, and the same dosage was injected again, 4 weeks later, in the same animals. The intradiscal pressure was measured at 1, 4, 8, and 12 weeks after the second injection. The remaining six rabbits were used as controls, without puncture and without injection. The intradiscal pressure of the group with repeat hypertonic saline injection at 4 weeks was significantly lower than that of the control group. The decreased pressure showed a tendency to increase at 8 weeks, and it had recovered at 12 weeks. The results of this study suggest that repeat hypertonic saline injections may be clinically useful.

Proline/arginine-rich end leucine-rich repeat protein converts stem cells to ligament tissue and Zn(II) influences its nuclear expression

Our objective was to facilitate ligament tissue reconstruction by characterizing the mechanism of expression of ligament tissue. To accomplish this, we searched for proteins specific to the tissue and introduced them into mesenchymal stem cells. In the two-dimensional phosphorescent gel electrophoresis, the spots in common with the normal human ligament tissue were selected after removing the spots of the normal bone tissue from those of the ossified tissue in the spinal ligament. Proline/arginine-rich end leucine-rich repeat protein (PRELP) was identified in ligament-specific locations by liquid chromatography-tandem mass spectrometry. Transfection of PRELP into mouse mesenchymal stem cells yielded ligament-like connective tissue comprised of parallel fibers. Thus, expression of the PRELP protein could reconstruct the ligament tissue. Since zinc-related proteins were found with high incidence as a result of an array analysis of PRELPs ProtoArray, it was considered that there is a relationship to the zinc metabolism. Tissue induction was mediated by the tumor necrosis factor (TNF)-α via the zinc pathway. PRELP may be a useful gene in syndesmoplasty, provided zinc is present for tissue reconstruction. Chromosome division becomes active with the addition of zinc, and rapid tissue induction takes place in the presence of zinc and TNF-α. Currently, the reconstruction of a ruptured ligament tissue is difficult, but we expect that the PRELP protein expression may facilitate this process. This study describes the discovery of the gene responsible for the differentiation of stem cells into ligament tissue. This important finding may lead to treatments for gonarthrosis, cruciate ligament, and periodontal ligament ruptures, and ossification of the posterior longitudinal ligament.

Up-Regulation in Receptor for Advanced Glycation End-Products in Inflammatory Circumstances in Bovine Coccygeal Intervertebral Disc Specimens In Vitro

Study Design. This study investigated whether or not the receptor for advanced glycation end-products (RAGE) was up-regulated in inflammatory circumstances and consequently associated with aggrecan content in nucleus pulposus in vitro. Objective. To investigate the activation of AGEs-RAGE complex by the irritation of IL-1&bgr; in bovine intervertebral disc (IVD). Summary of Background Data. Although we have demonstrated that the accumulation of AGEs contributed to disc degeneration in human, it may be that acceleration in the AGEs-RAGE complex might be more important, mediated by expression levels of RAGE that increase in inflammatory mediators including IL-1&bgr; in some tissues. Therefore, we investigated, in this study, the correlation if any between IL-1&bgr; and AGEs-RAGE complex in bovine IVD. Methods. Samples of bovine coccygeal IVDs were harvested (n = 6). The presence of AGEs and RAGE were identified by immunohistochemistry. Real-time polymerase chain reaction (PCR) was used to quantify the messenger RNA levels of aggrecan after 6 days’ stimulation of AGEs. Real-time PCR and immunofluorescein cytochemistry were performed to analyze the expression of RAGE after 2 days’ stimulation of IL-1&bgr;. The aggrecan expressions were evaluated by real-time PCR after 2 days’ stimulation of combination of AGEs and/or IL-1&bgr;. Results. Immunohistochemical analysis revealed that AGEs and RAGE were localized within the bovine IVDs. AGEs significantly decreased the aggrecan expression in bovine IVD as in human IVD. The RAGE expression was significantly increased by 2 days’ stimulation of IL-1&bgr;. The aggrecan expression was decreased by stimulated AGEs and IL-1&bgr; together, although not decreased by stimulated AGEs or IL-1&bgr; separately. Conclusion. This is the first report to show the correlation between IL-1&bgr; and AGEs-RAGE complex in IVD. Our results suggested that the increased RAGE expression in inflammatory circumstances and interaction with AGEs are risk factors in decreasing of aggrecan content in nucleus pulposus.

Effect of a nonprotein bioactive agent on the reduction of cyclooxygenase-2 and tumor necrosis factor-alpha in human intervertebral disc cells in vitro.

OBJECT Neurotropin is a nonprotein extract from the inflamed skin of rabbits inoculated with vaccinia virus. In the present study the authors sought to clarify the focal antiinflammatory effects of Neurotropin in intervertebral disc cells, and these effects were compared with those induced by the selective cyclooxygenase (COX)-2 inhibitor 6-methoxy-2-naphthylacetic acid (nabumetone). METHODS Six human intervertebral disc specimens were harvested during spinal surgery for lumbar disc herniation. Cells were stimulated with 500 pg/ml of interleukin (IL)-1beta in the presence of various concentrations of Neurotropin (0, 10(-5), 10(-4), and 10(-3) Neurotropin Units/ml) or 50 microg/ml of nabumetone for 3 hours. The mRNA was extracted for polymerase chain reaction (PCR), and real-time PCR was used to quantify the mRNA levels of COX- 2, tumor necrosis factor (TNF)-alpha, and phospholipase A2. Cyclooxygenase-2, TNFalpha, and prostaglandin E2 (PGE2) protein concentrations were each determined by enzyme-linked immunosorbent assay. RESULTS Neurotropin was found to significantly suppress the expression of COX-2 and TNFalpha at mRNA levels as well as the concentration of COX-2 at protein levels in a dose-dependent manner. Nabumetone was found to significantly increase COX-2 at mRNA levels but directly suppress the concentration of PGE2 in culture medium. CONCLUSIONS Results in this study suggest that Neurotropin has an analgesic effect through the suppression of COX-2 and TNFalpha in a focal area, and nabumetone shows this same effect through the suppression of PGE2 production. Thus, Neurotropin could decrease pain by blocking the central pain pathway or increasing focal antiinflammatory effects.

Immunohistochemical demonstration of advanced glycation end products and the effects of advanced glycation end products in ossified ligament tissues in vitro.

Study Design. This study correlates advanced glycation end products with ossified ligament tissues of the cervical spine in vitro. Objective. To investigate the effect of advanced glycation end products on ossification of the spinal ligaments in vitro. Summary of Background Data. We have hypothesized that an accumulation of advanced glycation end products in the spinal ligament might result in some observable change in specific growth factors responsible for ossification in the spinal ligaments. Methods. Samples of the posterior longitudinal and yellow ligaments were harvested from patients (n = 5) with ossification of the posterior longitudinal ligament, and analyzed for the presence of advanced glycation end products and their receptor advanced glycation end product receptor by immunohistochemistry. Real-time polymerase chain reaction (PCR) was used to quantify the messenger ribonucleic acid (mRNA) levels of bone morphogenetic protein (BMP)-2, BMP-7, alkaline phosphatase, an osteoblast-specific transcription factor 1 (Cbfa1), and osteocalcin from yellow ligament cells treated with advanced glycation end products. Results. Immunohistochemical analysis revealed that advanced glycation end products and advanced glycation end product receptor were localized to within the posterior longitudinal and yellow ligaments. Advanced glycation end products were found to increase significantly the expression of BMP-2, BMP-7, Cbfa1, and osteocalcin at the mRNA levels after treatment with advanced glycation end products (1 &mgr;g/mL). Conclusions. This is the first report to investigate the correlation, if any, between the ossified spinal ligament and advanced glycation end products. These results suggested that accumulation in advanced glycation end products and their interaction with advanced glycation end product receptor were 1 of the important risk factors in the process of ossification in the spinal ligaments.

Fall-related deterioration of subjective symptoms in patients with cervical myelopathy

Study design. Retrospective multi-center study. Objective. This study was conducted to clarify the incidence and neurological outcomes of fall-related deterioration of subjective symptoms in patients undergoing surgical treatment. Summary of Background Data. The evidence that minor trauma, including falls, increases the risk of worsening cervical myelopathy is insufficient. Methods. A retrospective analysis of patients who had undergone surgery for cervical myelopathy at 12 participating institutes was conducted. Patients who had undergone surgery for symptomatic cervical myelopathy from January 2012 to December 2013 and completed at least 1-year follow-up were included in this study. Data were collected by chart review and a questionnaire that included numbers of recalled falls during the last preoperative year and first postoperative year, circumstances of falls, and whether the patient had experienced fall-related deterioration of subjective symptoms. Results. A total of 360 eligible patients were recruited into the study. Of these, 177 (49%) reported at least one fall during the last preoperative year, and 105 (29%) experienced fall-related deterioration of subjective symptoms. Forty (11%) reported deterioration of numbness in the arms or legs, and 65 (18%) reported deterioration of motor deficits. Incidences of falls and fall-related deterioration of symptoms decreased significantly after surgery. Patients who experienced fall-related deterioration of motor deficits showed significantly worse surgical outcomes as assessed by Japanese Orthopaedic Association (JOA) score compared with those who did not experience deterioration. The optimal cut-off for preoperative JOA score in predicting an increased risk of fall-related deterioration in motor deficits was 8. Conclusion. Patients with cervical myelopathy commonly experienced preoperative fall-related deterioration of subjective symptoms, associated with significantly worse neurological outcomes. Surgical treatment significantly reduced the incidence of both falls and fall-related deterioration of subjective symptoms. Level of Evidence: 4

Diagnostic Imaging of Cervical Ossification of the Posterior Longitudinal Ligament

The range of ossifi cation in the ligaments of the cervical spine that can be examined using imaging include ossifi cation of the posterior longitudinal ligament (OPLL), ossifi cation of the yellow ligament (ligamentum fl avum) (OYL), ossifi cation of the anterior longitudinal ligament, and ankylosing spondylitis. OPLL is one of a group of diffuse idiopathic skeletal hyperostoses that can affect the various spinal ligaments. Cervical OPLL is the most common among this group and often leads to compression myelopathy. Clinical guidelines for diagnosing and treating OPLL were published in 2005 by a committee within the Japanese Orthopedic Association and funded by the Japanese Ministry of Public Health and Welfare [1]. This section describes the diagnostic imaging for cervical OPLL based on those clinical guidelines and on the research referred to by the guidelines. The presence of cervical OPLL is generally confi rmed on a lateral plain radiograph. Tomography and computed tomography (CT) are, however, much more sensitive for visualizing the detailed outlines of any ossifi ed mass. The guidelines committee proposed that the diagnostic criteria for OPLL include clear radiographic fi ndings as well as documentation of the clinical symptoms; thus, early small ossifi cation not visible on lateral plane radiography and that can be detected only by CT does not fulfi ll the diagnostic defi nition for OPLL [1]. Cervical OPLL

Three stress fractures at different sites in the same tibia-a case report

An 8-year-old boy who had no significant past medical history had right leg pain for 2 months while practicing judo and with walking. He had been participating in 2 hours of judo practice twice a week and running almost every day for 2 years. He denied direct trauma to the leg. The anterior midshaft of the right leg was tender, without swelling or redness. Plain radiographs revealed a lucent area in the anterior cortex of the midshaft of the tibia. A bone scan with technetium-99 demonstrated locally increased uptake at the site of symptoms. MRI showed an abnormal signal intensity at the same spot. These findings were compatible with a stress fracture of the midanterior cortex of the tibia. He was treated with cast immobilization, no weight bearing and ambulation on crutches. The cast was removed after 2 months and he had no pain on standing, although he complained of mild tenderness over the anterior midshaft of the tibia. The lucent area was visible on repeated radiographs, but less distinct than on the initial radiographs. We removed the cast and permitted ankle motion, no weight bearing and use of crutches, but prohibited physical activities for 3 more months. 3 months later, he still had some pain and radiographs demonstrated a lucent area in the anterior cortex with linear sclerotic changes in the upper third of the tibia. We continued prohibition of weight bearing on the right leg for 2 more months. Nevertheless, 2 months later he still had pain and radiographs revealed sclerotic changes in the lower third of the tibia, in addition to findings in the midshaft and upper third. At that time, he confessed that he had been running now and then in order to maintain his competitive level with fellow athletes. We strictly prohibited weight bearing and sports activities, except swimming. 4 months later, he said he had been following our recommendation and had no symptoms and radiographs were normal. 1 year later he had no symptoms. He had a normal physical constitution, normal skin condition, normal ocular and auditory systems, normal laxity and range of motion in his joints, with normal alignment of his legs. Laboratory findings including blood count, sedimentation rate, calcium, phosphate, alkaline phosphate, thyroid and parathyroid hormones were normal. There was no evidence of rickets at the end of the long bones and bone density was normal.

Clinical Studies of Expansive Laminoplasty for Ossification of the Posterior Longitudinal Ligament of the Cervical Spine.

We investigated the clinical results of 39 patients with ossification of the posterior longitudinal ligament (OPLL) of the cervical spine who underwent expansive laminoplasty by sagittal splitting of the spinous process (Kurokawa’s method), from January 1995 to October 2000. The mean age was 62 (42 to 75) years. The operative results were evaluated according to the Japanese Orthopaedic Association (JOA) score, after a mean follow-up period of 38 (12 to 77) months. The mean JOA score was 7.82 points before surgery and 12.73 points after surgery. The overall mean recovery rate by JOA score was 52.5%. The patients were divided into two groups; Group 1 consisting of 8 patients with spinal canal stenosis due to OPLL or ossification of the ligamentum flavum etc. at the thoracic and/or lumbar level, and Group 2 consisting of 31 patients without stenosis. The mean JOA score of Group 1 was 6.75 points before surgery and 10.94 points after surgery, while the score of Group 2 was 8.10 points before surgery and 13.20 points after surgery, with no significant difference in the score before surgery between the two groups. However, the JOA score after surgery was significantly lower in patients with spinal canal stenosis at the thoracic and/or lumbar level of Group 1, than the patients without stenosis in Group 2.