Yuichi Takano

Types of lumbar herniated disc and clinical course.

Study Design. A retrospective study of different types of herniated discs and duration of symptoms in patients with lumbar disc herniation, and a trial of longer conservative treatment to reduce the number of operations. Objective. To determine whether noncontained and contained herniated discs have different clinical courses and to evaluate the results of the clinical trial of longer and vigorous conservative treatment. Summary of Background Data. The possibility of a difference in clinical features between contained and noncontained disc herniation has been suggested previously. Methods. In the first study, the medical history and intraoperative findings of 156 patients who had undergone herniotomy were reviewed. In the second study, conservative treatment of at least 2 months’ duration was recommended for all patients with lumbar disc herniation. Results. In the first study, patients with noncontained disc herniation had a shorter preoperative clinical course than those with contained disc herniation. It was rare for noncontained herniation to require surgery 4 months or more after the onset of symptoms. In the second study, the authors’ protocol reduced the number of herniotomies required, especially the number of operations for the patients with noncontained disc herniation. Conclusions. The authors believe that patients with noncontained lumbar disc herniation can be treated without surgery, if these patients can tolerate the symptoms for the first 2 months.

Treatment with active vitamin D metabolites and concurrent treatments in the prevention of hip fractures: a retrospective study.

Abstract: The purpose of this study was to determine the effect of treatment with active vitamin D metabolites and other concurrent medication on the prevention of hip fractures in elderly women. We inspected the medical records of the entire female population over 65 years of age on Sado Island, and followed a total of 11377 women for a 3-year period. Of these, 1208 osteoporotic patients were treated with either 1,25-(OH)2D3 or 1α-(OH)D3. The 765 patients who received the minimum effective dosage for more than 6 months made up the ‘treatment group’. Nearly half these patients were also treated with either calcitonin or calcium. The 443 patients who received treatment with active vitamin D metabolites, but at a dosage or for a duration that did not meet the criteria for the treatment group, were deemed the ‘ineffective group’. The remaining 10169 women were the ‘non-treatment group’. Fractures in the non-treatment group occurred at a rate of 39.8 fractures/10000 person-years. The rate in the treatment group was 10.8, which was significantly lower (p= 0.039). Interestingly, the fracture rate after ceasing treatment was 52.1, which was significantly higher (p= 0.002) than the rate in patients receiving treatment. No statistical differences in the fracture rate were found between the ineffective, non-treatment and post-treatment groups. A reduction in the fracture rate was observed only in the treatment subgroup that did not also receive calcitonin (p= 0.042), and not in the subgroup that also received calcitonin therapy (p= 0.333). However, there was no statistical difference in the hip fracture rates between these two subgroups (p= 0.157) and the actual number of fractures was minimal (0 vs 2). Therefore, in this study, the advantage of treatment with active vitamin D alone over combined treatment with calcitonin seems to be marginal. In conclusion: (1) treatment with active vitamin D metabolites and with combined therapy may be marginally effective in preventing hip fractures, and (2) stopping the treatment clearly increases the risk of hip fractures.

A histomorphometric study on effects of single and concurrent intermittent administration of human PTH (1-34) and bisphosphonate cimadronate on tibial metaphysis in ovariectomized rats

This study compared the single administration of hPTH(1-34), bisphosphonate cimadronate (YM-175), and concurrent therapy of these two for restoration of lost bone mass in ovariectomized (OVX) rats. Animals were untreated for 4 weeks after surgery, and then injected s.c. with vehicle (OVX+V), hPTH(1-34) (30 micrograms/kg) (OVX+P), YM-175 (5 micrograms/kg) (OVX+Y), or a combination of these two (OVX+P+Y), 3 days a week, for 8 weeks, and sacrificed. Their proximal tibia were processed undecalcified for quantitative bone histomorphometry. Although OVX+Y showed a reduction of bone turnover compared to OVX+V, it failed to restore lost bone mass in OVX rats. In contrast, OVX+P exhibited a stimulation of bone formation and restored cancellous osteopenia due to OVX. OVX+P+Y also resulted a recovery of osteopenia, however, stimulation of bone formation by PTH was suppressed by YM-175.

Effects of human PTH(1-34) and bisphosphonate on the osteopenic rat model

It has been demonstrated that the intermittent administration of human parathyroid hormone (hPTH) is beneficial for restoration of bone mass in osteoporotic patients. The mechanisms of anabolic effects of hPTH have been determined by ovariectomized rat models and other larger remodeling animals. However, treatment with hPTH may increase the cancellous bone mass at the expense of cortical bone mass and cessation of the treatment results in rapid bone loss. Efforts have been made to maintain newly formed bone mass after withdrawal of the hPTH treatment. These issues are not well understood. In this article, the authors would like to represent previous studies of their own and others concerning these issues.

Clinical significance of cerebrospinal fluid nitric oxide concentrations in degenerative cervical and lumbar diseases

In animal models of degenerative lumbar disease, inducible nitric oxide synthase (iNOS) is expressed in macrophages and Schwann cells following compression of the cauda equina. We previously reported that NO metabolites (nitrite plus nitrate: [NOx]) in the cerebrospinal fluid (CSF) correlate with postoperative pain relief in patients with degenerative lumbar disease and with neurologic recovery rate postoperatively or after conservative treatment in patients with spinal cord injury. The objective of the present study was to examine the relationship between [NOx] and neurologic severity, and recovery in degenerative cervical and lumbar diseases. Two hundred fifty-seven cases, including 85 patients with cervical compression myelopathy (CCM), 25 with cervical disc herniation (CDH), 70 with lumbar canal stenosis (LCS), and 77 with lumbar disc herniation (LDH), were examined. The CSF [NOx] was measured using the Griess method. Severity of neurologic impairment and clinical recovery was assessed using the Japanese Orthopedic Association score and Hirabayashi’s method. [NOx] in CCM and LCS, but not CDH and LDH groups, was significantly higher than that in controls, and correlated with postoperative recovery rates, but not with preoperative neurologic severity. [NOx] significantly correlated with neurologic recovery following surgery for CCM and LCS.

Effects of single and concurrent intermittent administration of human parathyroid hormone and bisphosphonate cimadronate on bone mineral densities of femur in ovariectomized rats

This study compared the single administration of human parathyroid hormone [hPTH(1-34)] or bisphosphonate cimadronate (YM-175), and concurrent therapy with both of these agents for restoration of lost bone mineral density (BMD) in ovariectomized (OVX) rats. Animals were untreated for 4 weeks after surgery, and then injected s.c. with vehicle (OVX+V), hPTH(l-34) (30μg/kg) (OVX+P), YM-175 (5μg/kg) (OVX+Y), or a combination of these two (OVX+P+Y), 3 days a week, for 8 weeks, and killed. BMD of distal, middle, and total femur were determined by dual-energy X-ray absorptiometry (DXA). BMD of distal and total femur, but not of midfemur, decreased at both 4 weeks and 12 weeks after ovariectomy. In the distal femoral BMD, although OVX+Y failed to restore lost BMD in OVX rats, either OVX+P or OVX+P+Y could reverse BMD lost due to OVX. Midfemoral BMD was unchanged through OVX or both single treatments, whereas this parameter was increased only in OVX+P+Y. These results suggest that concurrent treatment with PTH and YM-175 results in a bone anabolic effect not only in cancellous bone but also in cortical bone.

Role of 18F-fluoro-D-deoxyglucose PET/CT in diagnosing surgical site infection after spine surgery with instrumentation.

Study Design. Retrospective case series. Objective. To investigate the effectiveness of positron emission tomography/computed tomography (PET/CT) in diagnosing surgical site infection (SSI) after spinal surgery with instrumentation. Summary of Background Data. Several reports have indicated the usefulness of 18F-fluoro-D-deoxyglucose (F-18 FDG) PET in detecting sites of infection including spinal infection sites. However, no report has documented the efficacy of PET/CT in detecting SSI after spinal surgery with instrumentation. Methods. A total of 811 consecutive case patients who underwent minimally invasive posterior lumbar interbody fusion surgery with instrumentation from December 2008 to February 2012 were enrolled. Of these, for all case patients clinically suspected as having SSI by laboratory data and clinical symptoms, PET/CT was performed. Six patients with no apparent sign of SSI served as a control group. Image data were evaluated by 2 nuclear medicine physicians blinded to the clinical and pathological results. The data were quantitatively analyzed by the maximum standardized uptake value as an index of F-18 FDG uptake. Results. Visual assessment by PET/CT revealed that all 8 patients with suspected SSI were positive for infection whereas all 6 controls without apparent infection were negative for infection. There was a statistically significant difference in the maximum standardized uptake values (mean and range) between the SSI and control groups (9.0 and 5.5–14.7 vs. 3.3 and 2.0–4.3, respectively; P = 0.003). All 8 patients underwent surgical debridement with selective implant removal and achieved a good clinical course. Conclusion. PET/CT was effective in diagnosing SSI and identifying infection sites despite the presence of spinal instruments. Although further studies with a larger number of patients are required, PET/CT presents a good candidate for detecting early-phase SSI after instrumented spinal surgery. Level of Evidence: 4

Consideration of proper operative route for interlaminar approach for percutaneous endoscopic lumbar discectomy

BACKGROUND Percutaneous endoscopic lumbar discectomy (PELD) is one of the less invasive treatments of lumbar disc herniation (LDH), and has three different operative approaches. This study focused on the interlaminar approach (ILA) and investigated the appropriate operative route for this approach. METHODS ILA was performed in 41 patients with LDH. The width of the interlaminar space, LDH size, and positional relation between LDH and the corresponding nerve root were radiologically evaluated. Thirty-three LDHs were removed via the shoulder of the corresponding nerve root and eight were removed via the axilla of the corresponding nerve root and dural sac. Pre- and postoperative status were evaluated using the modified Japanese Orthopedic Association (mJOA) and numerical rating scale (NRS) scores. RESULTS The mean age was 41.5 years; there was single-level involvement, mostly at L5/S1 (33 cases). The mean recovery rate of mJOA score was 59.8% and mean pre- and postoperative NRS scores were 5.8 and 0.98, respectively. Relatively severe complications developed in three patients treated by ILA via the shoulder. There was persistent numbness in the corresponding nerve area, transient muscular weakness, and transient bladder and rectal disturbance, may be due to excessive compression of the nerve root and/or dural sac by the endoscopic sheath. CONCLUSIONS ILA can be used to treat LDH revealing an interlaminar space of ≥20 mm. The procedure is minimally invasive and effective; however, appropriate selection of an operative route is important to avoid operative complications. Particularly for large LDH, the operative route via the axilla should be considered.

Microendoscopic Posterior Decompression for the Treatment of Lumbar Lateral Recess Stenosis

Lateral recess stenosis (LRS) is a characteristic type of lumbar spinal canal stenosis, with symptoms of nerve root compression. The most common etiology is hypertrophy of the superior articular process. Conventional laminectomy and medial facetectomy are commonly used to treat LRS. This study investigated microendoscopic posterior decompression for the treatment of LRS. Microendoscopic decompression was performed on 28 patients. Computed tomography and magnetic resonance imaging were used to calculate the lateral recess angle and depth. A 16 mm diameter tubular retractor and endoscopic system were used. Unilateral paramedian approaches were performed in all patients. Even using a unilateral paramedian approach, both sides of the nerve roots were decompressed in patients with bilateral radiculopathy. Preand postoperative status was evaluated using the visual analogue scale (VAS). Patient’s mean age was 62.9 years; there was single-level involvement, mostly at L4-5 (85.7%). Intraoperative findings revealed that the most common cause of nerve root compression was hypertrophy of the superior articular process and ligamentum flavum. VAS score improved in all patients following posterior decompression. Pre- and postoperative mean VAS scores were 6.5 and 1.1, respectively (P value < 0.01). No intra- or postoperative complications were observed during a mean follow-up of 10.5 months.

Does intrawound vancomycin powder reduce surgical site infection after posterior instrumented spinal surgery? A propensity score-matched analysis

BACKGROUND CONTEXT Recent reports suggested that placing vancomycin powder into surgical wounds before closure can prevent surgical site infections (SSIs) in spinal surgery. PURPOSE The present study aimed to evaluate if intrawound vancomycin powder could prevent SSIs after spinal surgery with posterior instrumentation. STUDY DESIGN This is a multicenter retrospective cohort study using propensity score matching. PATIENT SAMPLE We reviewed all spinal surgeries performed with posterior instrumentation from July 2012 to December 2014 at 11 institutions among patients aged ≥15 years. OUTCOME MEASURES The incidence of SSIs was compared between patients who received intrawound vancomycin powder (vancomycin group) and those who did not (control group). METHODS Demographic and operative data and microbiological findings of SSI cases were analyzed. After a preliminary whole-cohort analysis, we performed one-to-one propensity score matching to adjust for the differences between the two groups and then compared the incidence of SSIs between the matched groups. No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript. RESULTS A total of 2,859 patients were included in the study. In the vancomycin and control groups (n=694 and n=2165, respectively), 12 (1.73%) and 21 (0.97%) patients developed SSIs, respectively, but the difference was not statistically significant (p=.10, chi-square test). During the propensity score-matched analysis, 507 pairs were analyzed. No significant change in the rate of SSIs was seen between the vancomycin and control groups (8 SSIs [1.58%] vs. 9 SSIs [1.78%], respectively; p=.81, chi-square test). Microbiological analysis revealed that 5 of 12 (42%) and 11 of 21 (52%) SSIs in the vancomycin and control groups, respectively, were caused by Staphylococcus (p=.72, Fisher exact test). CONCLUSIONS Intrawound application of vancomycin powder was not associated with a significant decrease in the incidence of SSIs after posterior instrumented spinal surgeries in a propensity score-matched analysis. However, the rate of infections caused by Staphylococcus species was lower in the vancomycin group.