Comparative Analysis of Microendoscopic and Open Laminectomy for Single-Level Lumbar Spinal Stenosis at L1-L2 or L2-L3

BACKGROUND

Several reports have highlighted comparable surgical outcomes between microendoscopic laminectomy (MEL) and open laminectomy (open) for lumbar spinal stenosis. However, the unilateral approach in MEL may present challenges for the upper lumbar levels, where facet joints are located deeper inside. Our objective was to compare surgical outcomes and radiographic evaluations for single-level decompression cases at L1-L2 or L2-L3 between MEL and open laminectomy.

METHODS

We analyzed patients who underwent single-level decompression for upper lumbar spinal stenosis at 12 distinguished spine centers from April 2017 to September 2021. Baseline demographics, preoperative, and 1-year postoperative patient-reported outcomes, along with imaging parameters, were compared between the MEL and open groups. To account for potential confounding, patients' backgrounds were adjusted using the inverse probability weighting method based on propensity scores.

RESULTS

Among the 2487 patients undergoing decompression surgery, 118 patients (4.7%) underwent single-level decompression at L1-L2 or L2-L3. Finally, 80 patients (51 in the MEL group, 29 in the open group) with postoperative data were deemed eligible for analysis. The MEL group exhibited significantly improved postoperative EuroQol 5-Dimension values compared to the open group. Additionally, the MEL group showed a lower facet preservation rate according to computed tomography examination, whereas the open group had a higher incidence of retrolisthesis.

CONCLUSIONS

Although overall surgical outcomes were similar, the MEL group demonstrated potential advantages in enhancing EuroQol 5-Dimension scores. The MEL group's lower facet preservation rate did not translate into a higher postoperative instability rate.

Coexisting Lower Back Pain in Patients With Cervical Myelopathy

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The aim of the present study is to investigate the coexisting lower back pain (LBP) in patients with cervical myelopathy and to evaluate changes in LBP after cervical spine surgery.

SUMMARY OF BACKGROUND DATA

Only a few studies with a small number of participants have evaluated the association between cervical myelopathy surgery and postoperative improvement in LBP.

METHODS

Patients who underwent primary cervical decompression surgery with or without fusion for myelopathy and completed preoperative and 1-year postoperative questionnaires were reviewed using a prospectively collected database involving 9 tertiary referral hospitals. The questionnaires included the patient-reported Japanese Orthopaedic Association (PRO-JOA) score and Numerical Rating Scales (NRS). The minimum clinically important difference (MCID) for NRS-LBP was defined as >30% improvement from baseline. Patient demographics, characteristics, and PRO-JOA score were compared between patients with and without concurrent LBP, and the contributor to achieving the MCID for LBP was analyzed using logistic regression analysis.

RESULTS

A total of 786 consecutive patients with cervical myelopathy were included, of which 525 (67%) presented with concurrent LBP. LBP was associated with a higher body mass index (P<0.001) and worse preoperative PRO-JOA score (P<0.001). Among the 525 patients with concurrent LBP, the mean postoperative NRS-LBP significantly improved from 4.5±2.4 to 3.4±2.7 (P<0.01) postoperatively, with 248 (47%) patients reaching the MCID cutoff. Patients with a PRO-JOA recovery rate >50% were more likely to achieve MCID compared with those with a recovery rate <0% (adjusted odd ratio 4.02, P<0.001).

CONCLUSIONS

More than 50% of patients with myelopathy reported improvement in LBP after cervical spine surgery, and 47% achieved the MCID for LBP, which was positively correlated with a better PRO-JOA recovery rate. Treating cervical myelopathy in patients with concomitant LBP may be sufficient to mitigate concomitant LBP.

LEVEL OF EVIDENCE

Level Ⅲ.

Impact of the COVID-19 pandemic on surgical volume and outcomes in spine surgery: a multicentre retrospective study in Tokyo

OBJECTIVES

To investigate the effect of the COVID-19 pandemic on surgical volume and outcomes in spine surgery.

DESIGN

A retrospective cohort study using prospectively collected data.

SETTING AND PARTICIPANTS

A total of 9935 patients who underwent spine surgery between January 2019 and December 2021 at eight high-volume spine centres in the Greater Tokyo metropolitan area were included.

OUTCOME MEASURES

The primary outcome measures were the number of surgical cases, perioperative complications and patient-reported outcomes, including numerical rating scales for each body part, Euro quality of life 5-dimension (EQ5D), Neck Disability Index and Oswestry Disability Index (ODI).

RESULTS

The total number of surgeries in 2020 and 2021 remained lower than that of 2019, with respective percentages of 93.1% and 95.7% compared with the prepandemic period, with a marked reduction observed in May 2020 compared with the same period in 2019 (56.1% decrease). There were no significant differences between the prepandemic and postpandemic groups in the incidence of perioperative complications, although the frequency of reoperation tended to be higher in the postpandemic group (3.04% vs 3.76%, p=0.05). Subgroup analysis focusing on cervical spine surgery revealed significantly worse preoperative EQ5D scores in the postpandemic group (0.57 vs 0.54, p=0.004). Similarly, in lumbar spine surgery, the postpandemic group showed higher levels of leg pain (5.7 vs 6.1 to 0.002) and worse ODI scores (46.2 vs 47.7 to 0.02). However, postoperative outcomes were not different between pre and post-pandemic groups.

CONCLUSIONS

The COVID-19 pandemic has significantly impacted spinal surgeries in Japan, leading to a decrease in surgical volumes and changes in patient characteristics and surgical procedures. However, surgical outcomes remained comparable between the pre and postpandemic periods, indicating the resilience and adaptability of healthcare systems.

Does surgical site infection affect patient-reported outcomes after spinal surgery? A multicenter cohort study

BACKGROUND

Surgical site infections are common in spinal surgeries. It is uncertain whether outcomes in spine surgery patients with vs. without surgical site infection are equivalent. Therefore, we assessed the effects of surgical site infection on postoperative patient-reported outcomes.

METHODS

We enrolled patients who underwent elective spine surgery at 12 hospitals between April 2017 and February 2020. We collected data regarding the patients' backgrounds, operative factors, and incidence of surgical site infection. Data for patient-reported outcomes, namely numerical rating scale, Neck Disability Index/Oswestry Disability Index, EuroQol Five-Dimensional questionnaire, and 12-Item Short-Form Health Survey scores, were obtained preoperatively and 1 year postoperatively. We divided the patients into with and without surgical site infection groups. Multivariate logistic regression analyses were performed to identify the risk factors for surgical site infection. Using propensity score matching, we obtained matched surgical site infection-negative and -positive groups. Student's t-test was used for comparisons of continuous variables, and Pearson's chi-square test was used to compare categorical variables between the two matched groups and two unmatched groups.

RESULTS

We enrolled 8861 patients in this study; 74 (0.8 %) developed surgical site infections. Cervical spine surgery and American Society of Anesthesiologists physical status classification ≥3 were identified as risk factors; microendoscopy was identified as a protective factor. Using propensity score matching, we compared surgical site infection-positive and -negative groups (74 in each group). No significant difference was found in postoperative pain or dysesthesia of the lower back, buttock, leg, and plantar area between the groups. When comparing preoperative with postoperative pain and dysesthesia, statistically significant improvement was observed for both variables in both groups (p < 0.01 for all variables). No significant differences were observed in postoperative outcomes between the matched surgical site infection-positive and -negative groups.

CONCLUSIONS

Patients with surgical site infections had comparable postoperative outcomes to those without surgical site infections.

Ethanol Sclerosis Therapy for Aggressive Vertebral Hemangioma of the Spine: A Narrative Review

Vertebral hemangiomas of the spine are rare benign tumors. They occur primarily in the thoracic region and are often asymptomatic and found incidentally on radiological examination; however, some are symptomatic, aggressive, and gradually increase in size. Various therapeutic approaches have been proposed for their management. This study aimed to review the therapeutic management, focusing on ethanol sclerosis therapy. The PubMed database was searched from inception to January 2023 using the keywords "hemangioma", "spine OR vertebra", and "ethanol". Twenty studies were retrieved, including two letters. The first report of spinal therapy was published in 1994. Ethanol sclerosis therapy is effective in treating vertebral hemangiomas. It is performed independently or in combination with other techniques, such as vertebroplasty using cement and surgery. The therapy is performed under local or general anesthesia with fluoroscopic or computed tomography guidance. A total of 10-15 mL of ethanol is slowly injected via unilateral or bilateral pedicles. Complications of the therapy include hypotension and arrhythmia during the procedure, paralysis immediately after the procedure, and delayed compression fractures. This review could enable the refinement of knowledge regarding ethanol sclerosis therapy, which is a treatment option that could be adopted.

Tips and Complications of Two-step Open Procedure for Ethanol Sclerosis Therapy for a Venous Hemangioma of the Thoracic Spine: A Case Report

Introduction

Venous hemangiomas of the thoracic spine are rare tumors that are diagnose based on radiological findings. Ethanol sclerosis therapy through the percutaneous or open approaches has been reported to be useful treatment options. Therefore, radiological examination and the treatment procedure can be performed together. As pathological diagnosis of the tumor is important, a strategy that comprises biopsy followed by definitive treatment is ideal. The tips and complications of the two-step open procedure for ethanol sclerosis therapy have not been discussed in detail. This is the first report of this kind in the literature, especially about the tips and complications.

Case Report

A 51-year-old woman presented with pain in the upper part of her back. Radiological examination revealed a hypervascular tumor at the second thoracic vertebra. We first performed an open biopsy along with decompression and fixation surgery, because the patient developed a walking disability with motor weakness in her right leg. The tumor was pathologically diagnosed as a venous hemangioma. Therefore, we performed ethanol sclerosis therapy using the open approach as a curative technique for the tumor 17 days after the initial surgery. A total of 10 mL of a mixture of 100% ethanol and a lipid-soluble contrast medium - which improve visibility - was injected intermittently and slowly. This was followed by the injection of 3 mL of a water-soluble contrast medium to confirm sclerosis. Immediately after the last procedure, the amplitudes of motor-evoked potentials in all bilateral lower extremity muscles disappeared simultaneously. The patient incomplete paralysis of the lower extremity and transient dysuria postoperatively; however, she could walk without assistance after 5 months.

Conclusion

This case highlights the following: First, the two-step procedure of open biopsy followed by ethanol injection using the open approach allowed accurate diagnosis and effective treatment. Second, additional injection of a water-soluble contrast medium to confirm sclerosis after ethanol injection can cause paralysis. Third, a mixture of ethanol and a lipid-soluble contrast medium effective improves visibility to identify expansions. These experiences will be useful for following ethanol sclerosis therapy for a venous hemangioma of the thoracic spine.

Impact of body mass index on outcomes after lumbar spine surgery

The impact of body mass index (BMI) on outcomes after lumbar spine surgery is currently unknown. Previous studies have reported conflicting evidence for patients with high BMI, while little research has been conducted on outcomes for underweight patients. This study aims to examine the impact of BMI on outcomes after lumbar spine surgery. This prospective cohort study enrolled 5622 patients; of which, 194, 5027, and 401 were in the low (< 18.5 kg/m²), normal (18.5-30), and high (≥ 30) BMI groups, respectively. Pain was assessed via the numerical pain rating scale (NPRS) for the lower back, buttock, leg, and plantar area. Quality of life was assessed via the EuroQol 5 Dimension (EQ-5D) and Oswestry Disability Index (ODI). Inverse probability weighting with propensity scores was used to adjust patient demographics and clinical characteristics between the groups. After adjustment, the 1-year postoperative scores differed significantly between groups in terms of leg pain. The proportion of patients who achieved a 50% decrease in postoperative NPRS score for leg pain was also significantly different. Obese patients reported less improvement in leg pain after lumbar spine surgery. The outcomes of patients with low BMI were not inferior to those of patients with normal BMI.

Predictors for hemostatic thrombin-gelatin matrix usage in spine surgery: a multicenter observational study

STUDY DESIGN

A prospective cohort study.

OBJECTIVES

Thrombin-gelatin matrix (TGM) is a rapid and potent hemostatic agent, but it has some limitations, including the cost and its preparation time. The purpose of this study was to investigate the current trend in the use of TGM and to identify the predictors for TGM usage in order to ensure its proper use and optimized resource allocation.

METHODS

A total of 5520 patients who underwent spine surgery in a multicenter study group within a year were included in the study. The demographic factors and the surgical factors including spinal levels operated, emergency surgery, reoperation, approach, durotomy, instrumented fixation, interbody fusion, osteotomy, and microendoscopy-assistance were investigated. TGM usage and whether it was routine or unplanned use for uncontrolled bleeding were also checked. A multivariate logistic regression analysis was used to identify predictors for unplanned use of TGM.

RESULTS

Intraoperative TGM was used in 1934 cases (35.0%), among which 714 were unplanned (12.9%). Predictors of unplanned TGM use were female gender (adjusted odds ratio [OR]: 1.21, 95% confidence interval [CI]: 1.02-1.43, p = 0.03), ASA grade ≥ 2 (OR: 1.34, 95% CI: 1.04-1.72, p = 0.02), cervical spine (OR: 1.55, 95% CI: 1.24-1.94, p < 0.001), tumor (OR: 2.02, 95% CI: 1.34-3.03, p < 0.001), posterior approach (OR: 1.66, 95% CI: 1.26-2.18, p < 0.001), durotomy (OR: 1.65, 95% CI: 1.24-2.20, p < 0.001), instrumentation (OR: 1.30, 1.03-1.63, p = 0.02), osteotomy (OR: 5.00, 2.76-9.05, p < 0.001), and microendoscopy (OR: 2.24, 1.84-2.73, p < 0.001).

CONCLUSIONS

Many of the predictors for unplanned TGM use have been previously reported as risk factors for intraoperative massive hemorrhaging and blood transfusion. However, other newly revealed factors can be predictors of bleeding that is technically challenging to control. While routine usage of TGM in these cases will require further justification, these novel findings are valuable for implementing preoperative precautions and optimizing resource allocation.

A Propensity Score-matched Analysis of Clinical Outcomes Between Single-level and Multilevel Intervertebral Decompression for Cervical Radiculopathy

STUDY DESIGN

Retrospective multicenter study with propensity score matching.

OBJECTIVE

To compare the clinical outcomes of single-level and multilevel intervertebral decompression for cervical degenerative radiculopathy.

SUMMARY OF BACKGROUND DATA

In patients with cervical radiculopathy, physical examination findings are sometimes inconsistent with imaging data. Multilevel decompression may be necessary for multiple foraminal stenosis. Additional decompression is more invasive yet expected to comprehensively decompress all suspected nerve root compression areas. However, the surgical outcomes of this approach compared with that of single-level decompression remain unknown.

MATERIALS AND METHODS

The data of patients with spinal surgery for pure cervical radiculopathy were collected. Patients were categorized into the single-level (SLDG) or multilevel (MLDG) intervertebral decompression group at C3/C4/C5/C6/C7/T1. Demographic data and patient-reported outcome scores, including the Neck Disability Index (NDI) and Numerical Rating Scale (NRS) scores for pain and numbness in the neck, upper back, and arms, were collected. The NDI improvement rates and changes in NRS scores were analyzed one year postoperatively at patient-reported outcome evaluation. Propensity score matching was performed to compare both groups after adjusting for baseline characteristics, including the preoperative NDI and NRS scores.

RESULTS

Among the 357 patients in this study, SLDG and MLDG comprised 231 and 126 patients, respectively. Two groups (n=112, each) were created by propensity score matching. Compared with the MLDG, the SLDG had a higher postoperative NDI improvement rate ( P =0.029) and lower postoperative arm numbness NRS score ( P =0.037). Other outcomes tended to be more favorable in the SLDG than in the MLDG, yet no statistical significance was detected.

CONCLUSIONS

In patients with cervical radiculopathy, the surgical outcomes of the SLDG showed better improvement in clinical outcomes than those of the MLDG. Numbness remained on the distal (arms) rather than the central (neck and upper back) areas in patients receiving multilevel decompression.

Surgical outcomes between posterior decompression alone and posterior decompression with fusion surgery among patients with Meyerding grade 2 degenerative spondylolisthesis: a multicenter cohort study

Background

Whether lumbar decompression with fusion surgery is effective against Meyerding grade 2 degenerative spondylolisthesis (DS) is unknown. Therefore, the current study aimed to compare the surgical outcomes between posterior decompression alone and posterior decompression with fusion surgery among patients with grade 2 DS with central canal stenosis.

Methods

This retrospective cohort study included prospectively registered patients (n = 3863) who underwent surgery for degenerative lumbar spinal canal stenosis at nine high-volume spine centers from April 2017 to July 2019. Patients with grade 2 DS and central canal stenosis were included in the analysis. Patients with radiculopathy, including foraminal stenosis, degenerative scoliosis, and concomitant anterior spinal fusion, and those with a previous history of lumbar surgery were excluded. The participants were divided into the decompression alone group (group D) and decompression with fusion surgery group (group F). Data about patient-reported outcomes, including Numeric Rating Scale (low back pain, leg pain, leg numbness, and foot numbness), Oswestry Disability Index, EuroQol Five-Dimensional questionnaire, and 12-Item Short-Form Health Survey scores, were obtained preoperatively and 2 years postoperatively.

Results

In total, 2354 (61%) patients, including 42 (1.8%) with grade 2 DS (n = 18 in group D and n = 24 in group F), completed the 2-year follow-up. Group D had a higher proportion of female patients than group F. However, the two groups did not significantly differ in terms of other baseline demographic characteristics. Group D had a significantly shorter surgical time and lower volume of intraoperative blood loss than group F. Postoperative patient-reported outcomes did not significantly differ between the two groups, although the preoperative degree of low back pain was higher in group F than in group D. The slip degree of group D did not worsen during the follow-up period.

Conclusion

The surgical outcomes were similar regardless of the addition of fusion surgery among patients with grade 2 DS. Decompression alone was superior to decompression with fusion surgery as it was associated with a lower volume of intraoperative blood loss and shorter surgical time.

Postoperative outcomes after degenerative lumbar spine surgery in rheumatoid arthritis patients -a propensity score-matched analysis

Background

Although treatment options for rheumatoid arthritis (RA) have evolved significantly since the introduction of biologic agents, degenerative lumbar disease in RA patients remains a major challenge. Well-controlled comparisons between RA patients and their non-RA counterparts have not yet been reported. The objective of the present study was to compare postoperative outcomes of lumbar spine surgery between RA and non-RA patients by a retrospective propensity score-matched analysis.

Methods

Patients who underwent primary posterior spine surgery for degenerative lumbar disease in our prospective multicenter study group between 2017 and 2020 were enrolled. Demographic data including age, sex, body mass index (BMI), American Society of Anesthesiologists (ASA) physical status classification, diabetes mellitus, smoking, steroid usage, number of spinal levels involved, and preoperative patient-reported outcome (PRO) scores (numerical rating scale [NRS] for back pain and leg pain, Short Form-12 physical component summary [PCS], EuroQOL 5-dimension [EQ-5D], and Oswestry Disability Index [ODI]) were used to calculate a propensity score for RA diagnosis. One-to-one matching was performed and 1-year postoperative outcomes were compared between groups.

Results

Among the 4567 patients included, 90 had RA (2.0%). RA patients in our cohort were more likely to be female, with lower BMI, higher ASA grade and lower current smoking rate than non-RA patients. Preoperative NRS scores for leg pain, PCS, EQ-5D, and ODI were worse in RA patients. Propensity score matching generated 61 pairs of RA and non-RA patients who underwent posterior lumbar surgery. After background adjustment, RA patients reported worse postoperative PCS (28.4 vs. 37.2, p = 0.008) and EQ-5D (0.640 vs. 0.738, p = 0.03), although these differences were not significant between RA and non-RA patients not on steroids.

Conclusions

RA patients showed worse postoperative quality of life outcomes after posterior surgery for degenerative lumbar disease, while steroid-independent RA cases showed equivalent outcomes to non-RA patients.

Effect of Antimicrobial Prophylaxis Duration on Health Care-Associated Infections After Clean Orthopedic Surgery: A Cluster Randomized Trial

IMPORTANCE

Postoperative health care-associated infections are associated with a greater deterioration in patients' general health status and social and economic burden, with at least 1 occurring in approximately 4% of acute care hospital patients. Antimicrobial prophylaxis prevents surgical site infections in various orthopedic procedures; however, its relationship with health care-associated infections remains unknown.

OBJECTIVE

To examine whether a shorter antimicrobial prophylaxis duration of less than 24 hours after surgery is not inferior to a longer duration in preventing health care-associated infections after clean orthopedic surgery.

DESIGN, SETTING, AND PARTICIPANTS

This open-label, multicenter, cluster randomized, noninferiority clinical trial was conducted in 5 tertiary referral hospitals in greater Tokyo metropolitan area, Japan, from May to December 2018. Adult patients undergoing clean orthopedic surgery were recruited until the planned number of participants was achieved (500 participants per group). Statistical analysis was conducted from July to December 2019.

INTERVENTIONS

Antimicrobial prophylaxis was discontinued within 24 hours after surgery in group 24 and 24 to 48 hours after surgery in group 48. Group allocation was switched every 2 or 4 months according to the facility-based cluster rule. Study-group assignments were masked from participants.

MAIN OUTCOMES AND MEASURES

The primary outcome was the incidence of health care-associated infections requiring antibiotic therapies within 30 days after surgery. The noninferiority margin was 4%.

RESULTS

Of the 1211 participants who underwent cluster allocation, 633 participants were in group 24 (median [IQR] age, 73 [61-80] years; 250 men [39.5%] and 383 women [60.5%]), 578 participants were in group 48 (median [IQR] age, 74 [62-81] years; 204 men [35.3%] and 374 women [64.7%]), and all were eligible for the intention-to-treat analyses. Health care-associated infections occurred in 29 patients (4.6%) in group 24 and 38 patients (6.6%) in group 48. Intention-to-treat analyses showed a risk difference of -1.99 percentage points (95% CI, -5.05 to 1.06 percentage points; P < .001 for noninferiority) between groups, indicating noninferiority. Results of adjusted intention-to-treat, per-protocol, and per designated procedure population analyses supported this result, without a risk of antibiotic resistance and prolonged hospitalization.

CONCLUSIONS AND RELEVANCE

This cluster randomized trial found noninferiority of a shorter antimicrobial prophylaxis duration in preventing health care-associated infections without an increase in antibiotic resistance risk. These findings lend support to the global movement against antimicrobial resistance and provide additional information on adequate antimicrobial prophylaxis for clean orthopedic surgery.

TRIAL REGISTRATION

Identifier: UMIN000030929.

Minimal clinically important difference in patients who underwent decompression alone for lumbar degenerative disease

BACKGROUND CONTEXT

The minimal clinically important difference (MCID) represents the smallest change in an outcome measure recognized as clinically meaningful to a patient after receiving a clinical intervention. Most studies that discussed the MCIDs for lumbar spinal stenosis (LSS) included mixed pathologies or procedures despite that the MCID value should be different depending on the intervention. Moreover, despite the efficacy of adopting percentage-change improvement for the MCID threshold, there are limited reports and discussions in the field of lumbar surgery.

PURPOSE

The aim of the present study was to elucidate the MCIDs for the Oswestry Disability Index (ODI), EuroQOL 5-dimension 3-level (EQ-5D-3L), physical component summary (PCS) of the Short Form of the Medical Outcomes Study, and Numeric Rating Scale (NRS) in patients with degenerative LSS treated with decompression surgery without fusion.

STUDY DESIGN/SETTING

A multicenter retrospective cohort study was performed.

PATIENT SAMPLE

A total of 422 patients who underwent decompression surgery for LSS and answered a complete set of questionnaires were included in the study. Patients who underwent endoscopic or revision surgery were excluded.

OUTCOME MEASURES

Preoperative and 1-year postoperative scores of each health-related quality of life questionnaires (HRQOLs) and patient satisfaction questionnaire response METHODS: The patient satisfaction question was used as an anchor, and the cutoff values were estimated based on absolute point improvement from baseline using a receiver-operating characteristic (ROC) curve analysis and the "mean change" method for MCIDs. The MCID values for percentage-change in HRQOLs were also calculated using ROC curve analysis. The three cutoff values for each HRQOL were validated using the Youden index for determining the most robust MCIDs.

RESULTS

Of the patients, 356 (84.4%) were at least "somewhat satisfied" with the treatment results. The two cutoff values of absolute point-change in each HRQOL, which were estimated by two different anchor-based methods, were similar. The area under the curve of the ROC curve for percentage-change tended to be higher than that for absolute point-change. Moreover, the Youden index of the percentage-change in each HRQOL was higher than that of the absolute point-change calculated by either the "mean change" method or the ROC curve analysis. Based on these results, it was proposed that MCID was 42.4% for percentage-change in ODI, 22.0% for EQ-5D-3L, 13.7% for PCS, 25.0% for NRS (low back pain), 55.6% for NRS (leg pain), 22.2% for NRS (leg numbness).

CONCLUSIONS

The MCIDs of HRQOLs were calculated in patients with LSS treated with decompression surgery without concomitant fusion procedure. The MCID cutoffs based on percentage-change from baseline were more effective than those of absolute point-change.

Treatment of restenosis after lumbar decompression surgery: decompression versus decompression and fusion

OBJECTIVE

The aim of this study was to compare perioperative complications and postoperative outcomes between patients with lumbar recurrent stenosis without lumbar instability and radiculopathy who underwent decompression surgery and those who underwent decompression with fusion surgery.

METHODS

For this retrospective study, the authors identified 2606 consecutive patients who underwent posterior surgery for lumbar spinal canal stenosis at eight affiliated hospitals between April 2017 and June 2019. Among these patients, those with a history of prior decompression surgery and central canal restenosis with cauda equina syndrome were included in the study. Those patients with instability or radiculopathy were excluded. The patients were divided between the decompression group and decompression with fusion group. The demographic characteristics, numerical rating scale score for low-back pain, incidence rates of lower-extremity pain and lower-extremity numbness, Oswestry Disability Index score, 3-level EQ-5D score, and patient satisfaction rate were compared between the two groups using the Fisher's exact probability test for nominal variables and the Student t-test for continuous variables, with p < 0.05 as the level of statistical significance.

RESULTS

Forty-six patients met the inclusion criteria (35 males and 11 females; 19 patients underwent decompression and 27 decompression and fusion; mean ± SD age 72.5 ± 8.8 years; mean ± SD follow-up 18.8 ± 6.0 months). Demographic data and perioperative complication rates were similar. The percentages of patients who achieved the minimal clinically important differences for patient-reported outcomes or satisfaction rate at 1 year were similar.

CONCLUSIONS

Among patients with central canal stenosis who underwent revision, the short-term outcomes of the patients who underwent decompression were comparable to those of the patients who underwent decompression and fusion. Decompression surgery may be effective for patients without instability or radiculopathy.

Comparison between microendoscopic laminectomy and open posterior decompression surgery for single-level lumbar spinal stenosis: a multicenter retrospective cohort study

Background

Microendoscopic laminectomy (MEL), in which a 16-mm tubular retractor with an internal scope is used, has shown excellent surgical results for patients with lumbar spinal canal stenosis. However, no reports have directly compared MEL with open laminectomy. This study aimed to elucidate patient-reported outcomes (PROs) and perioperative complications in patients undergoing MEL versus open laminectomy.

Methods

This is a multicenter retrospective cohort study of prospectively registered patients who underwent lumbar spinal surgery at one of the six high-volume spine centers between April 2017 and September 2018. A total of 258 patients who underwent single posterior lumbar decompression at L4/L5 were enrolled in the study. With regard to demographic data, we prospectively used chart sheets to evaluate the diagnosis, operative procedure, operation time, estimated blood loss, and complications. The follow-up period was 1-year. PROs included a numerical rating scale (NRS) for lower back pain and leg pain, the Oswestry Disability Index (ODI), EuroQol 5 Dimension (EQ-5D), and patient satisfaction with the treatment.

Results

Of the 258 patients enrolled, 252 (97%) completed the 1-year follow-up. Of the 252, 130 underwent MEL (MEL group) and 122 underwent open decompression (open group). The MEL group required a significantly shorter operating time and sustained lesser intraoperative blood loss compared with the open group. The MEL group showed shorter length of postoperative hospitalization than the open group. The overall complication rate was similar (8.2% in the MEL group versus 7.7% in the open group), and the revision rate did not significantly differ. As for PROs, both preoperative and postoperative values did not significantly differ between the two groups. However, the satisfaction rate was higher in the MEL group (74%) than in the open group (53%) (p = 0.02).

Conclusions

MEL required a significantly shorter operating time and resulted in lesser intraoperative blood loss compared with laminectomy. Postoperative PROs and complication rates were not significantly different between the procedures, although MEL demonstrated a better satisfaction rate.

Influence of Perioperative Antithrombic Agent Discontinuation in Elective Posterior Spinal Surgery: A Propensity-Score-Matched Analysis

OBJECTIVE

To investigate the influence of perioperative antithrombotic agent (antiplatelet agents and anticoagulants) discontinuation in elective posterior spinal surgery in terms of bleeding complications, such as epidural hematoma and postoperative thromboembolism.

METHODS

We enrolled patients undergoing elective posterior spinal surgery at 9 hospitals between April 2017 and August 2020. We collected data regarding patient baseline characteristics, surgical details, intraoperative estimated blood loss, and postoperative complication rates, including epidural hematoma and thromboembolism. We divided the patients into a discontinuation group, in which antithrombic agents were discontinued perioperatively, and a control group without antithrombic agents. Propensity scores for taking any antithrombic agents were calculated, with 1-to-1 matching based on the estimated propensity scores to adjust for patient baseline characteristics and surgical details. Intraoperative estimated blood loss and 30-day postoperative complication rates were compared between the groups.

RESULTS

We enrolled 9853 patients, including 1123 patients (11.4%) who discontinued antithrombic agents perioperatively. One-to-one propensity score matching yielded 1111 pairs with and without antithrombic agents. Intraoperative estimated blood loss per 10 minutes (8.2 mL vs. 8.9 mL) and the incidence of epidural hematoma requiring revision (0.97% vs. 0.72%) were similar between the groups. Although postoperative cardiac events and stroke were observed only in the discontinuation group (0.27% and 0.09%, respectively), these incidences were not significantly different between the groups.

CONCLUSIONS

Perioperative antithrombic agent discontinuation in elective posterior spinal surgery normalized the intraoperative bleeding tendency and the incidence of postoperative epidural hematoma and did not influence in a significative way the incidence of postoperative thromboembolism.

Effect of Early vs Delayed Surgical Treatment on Motor Recovery in Incomplete Cervical Spinal Cord Injury With Preexisting Cervical Stenosis: A Randomized Clinical Trial

IMPORTANCE

The optimal management for acute traumatic cervical spinal cord injury (SCI) is unknown.

OBJECTIVE

To determine whether early surgical decompression results in better motor recovery than delayed surgical treatment in patients with acute traumatic incomplete cervical SCI associated with preexisting canal stenosis but without bone injury.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter randomized clinical trial was conducted in 43 tertiary referral centers in Japan from December 2011 through November 2019. Patients aged 20 to 79 years with motor-incomplete cervical SCI with preexisting canal stenosis (American Spinal Injury Association [ASIA] Impairment Scale C; without fracture or dislocation) were included. Data were analyzed from September to November 2020.

INTERVENTIONS

Patients were randomized to undergo surgical treatment within 24 hours after admission or delayed surgical treatment after at least 2 weeks of conservative treatment.

MAIN OUTCOMES AND MEASURES

The primary end points were improvement in the mean ASIA motor score, total score of the spinal cord independence measure, and the proportion of patients able to walk independently at 1 year after injury.

RESULTS

Among 72 randomized patients, 70 patients (mean [SD] age, 65.1 [9.4] years; age range, 41-79 years; 5 [7%] women and 65 [93%] men) were included in the full analysis population (37 patients assigned to early surgical treatment and 33 patients assigned to delayed surgical treatment). Of these, 56 patients (80%) had data available for at least 1 primary outcome at 1 year. There was no significant difference among primary end points for the early surgical treatment group compared with the delayed surgical treatment group (mean [SD] change in ASIA motor score, 53.7 [14.7] vs 48.5 [19.1]; difference, 5.2; 95% CI, -4.2 to 14.5; P = .27; mean [SD] SCIM total score, 77.9 [22.7] vs 71.3 [27.3]; P = .34; able to walk independently, 21 of 30 patients [70.0%] vs 16 of 26 patients [61.5%]; P = .51). A mixed-design analysis of variance revealed a significant difference in the mean change in ASIA motor scores between the groups (F1,49 = 4.80; P = .03). The early surgical treatment group, compared with the delayed surgical treatment group, had greater motor scores than the delayed surgical treatment group at 2 weeks (mean [SD] score, 34.2 [18.8] vs 18.9 [20.9]), 3 months (mean [SD] score, 49.1 [15.1] vs 37.2 [20.9]), and 6 months (mean [SD] score, 51.5 [13.9] vs 41.3 [23.4]) after injury. Adverse events were common in both groups (eg, worsening of paralysis, 6 patients vs 6 patients; death, 3 patients vs 3 patients).

CONCLUSIONS AND RELEVANCE

These findings suggest that among patients with cervical SCI, early surgical treatment produced similar motor regain at 1 year after injury as delayed surgical treatment but showed accelerated recovery within the first 6 months. These exploratory results suggest that early surgical treatment leads to faster neurological recovery, which requires further validation.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01485458; umin.ac.jp/ctr Identifier: UMIN000006780.

The Impact of Cefazolin Shortage on Surgical Site Infection Following Spine Surgery in Japan

STUDY DESIGN

Retrospective study using prospectively collected data.

OBJECTIVE

This study aimed to investigate the effect of alternative antimicrobial prophylaxis agents on surgical site infections (SSIs) after spine surgery.

SUMMARY OF BACKGROUND DATA

Although the use of alternative antimicrobial prophylaxis agents might have a negative effect on SSI prevention, their association with SSI risk in spine surgery remains unclear.

METHODS

We used the registry data of consecutive patients undergoing spine surgery from April 2017 to January 2020 in four institutions participating in the University of Tokyo Spine Group. Before March 2019, all institutions used cefazolin for antimicrobial prophylaxis. After March 2019, the institutions used broad-spectrum beta-lactam agents as an alternative due to a cefazolin shortage in Japan.

RESULTS

Among the 3841 enrolled patients (2289 males), 2024 received cefazolin and 1117 received alternative agents. The risk of reoperation for deep SSI within 30 days of spine surgery was significantly higher in the alternative antimicrobial prophylaxis agent group (adjusted odds ratio [aOR] 1.96; 95% confidence interval [CI], 1.15-3.35; P = 0.014). In subgroup analyses, the SSI risk was significantly higher in the thoracolumbar surgery group (aOR 1.98; 95% CI, 1.06-3.73; P = 0.03). A nonsignificant consistent trend was found in all other subgroups: posterior decompression (aOR 1.91; 95% CI, 0.86-4.21; P = 0.11); posterior fixation (aOR 2.05; 95% CI, 0.99-4.24; P = 0.05); and cervical spine surgery (aOR 2.30; 95% CI, 0.82-6.46; P = 0.11).

CONCLUSION

Alternative antimicrobial prophylaxis agents increased the risk of reoperation for SSI after spine surgery compared with cefazolin. Our study supports the current practice of using first-generation cephalosporins as first-line antimicrobial prophylaxis agents in spine surgery as recommended in multiple guidelines.Level of Evidence: 3.

Relative Risks and Benefits of Crossing the Cervicothoracic Junction During Multilevel Posterior Cervical Fusion: A Multicenter Cohort

OBJECTIVE

To compare the clinical and radiographic outcomes and complications in patients undergoing multilevel posterior cervical fusion surgery, ending at C7 or crossing the cervicothoracic junction (CTJ).

METHODS

A total of 96 patients undergoing multilevel posterior cervical fusion surgery ending at C7, T1, or T2 were screened. The patients who fulfilled the inclusion criteria were divided into 2 groups based on the lower instrumented vertebra (LIV) level: group C7 (ending at C7) and group T1-T2 (crossing the CTJ). The radiographic and clinical outcomes were compared between the 2 groups, and the risk factors for instrument failure at LIV were investigated.

RESULTS

In total, 73 patients (76%) completed at least 1 year follow-up and divided into group C7 (n = 43) and group T1-T2 (n = 30). Preoperative and postoperative radiographic parameters, the Japanese Orthopaedic Association score, and patient-reported outcomes were not significantly different between the 2 groups. Significantly longer surgical time, increased blood loss, and higher incidence rates of perioperative or postoperative complications were noted in group T1-T2. On the other hand, the incidence of instrument failures at LIV was significantly higher in group C7. Multivariate analysis showed that ending at C7, skipping screw insertion at the proximal vertebra adjacent to LIV, and a large postoperative cervical sagittal vertical axis (>40 mm) were risk factors for instrument failure at LIV.

CONCLUSIONS

Crossing the CTJ during multilevel posterior cervical fusion surgery reduced instrument failures at LIV, but increased the surgical invasiveness and perioperative and postoperative complications.

Risk factors for worsening sexual function after lumbar spine surgery and characteristics of non-responders to the questionnaire of sex life

PURPOSE

To precisely assess the Oswestry Disability Questionnaire (ODQ) and its total score (Oswestry Disability Index: ODI) and reveal characteristics of non-responders of the 8th item of ODQ (ODI-8) relating to sexual function. Furthermore, we evaluated risk factors for aggravation of postoperative sexual function.

METHODS

We enrolled patients undergoing lumbar spine surgery at eight hospitals between April 2017 and November 2018. Patients' background data and operative factors were collected. We also assessed pain or dysesthesia (lower back, buttock, leg, and plantar area) on a numerical rating scale, EuroQol 5 Dimension, core outcome measures index back, and ODI before and 1 year after surgery. Factor analysis was conducted for the ODQ. Non-responders of the ODI-8 were compared with full-responders using propensity score matching. Risk factors for worsening ODI-8 were evaluated by multivariate logistic regression analysis.

RESULTS

Of the 2,610 patients enrolled, 601 (23.0%) answered all but the ODI-8 item; these patients were likely to show better preoperative clinical symptoms than full-responders, even after adjusting for age and gender using propensity scores. Age, spinal deformity, and the American Society of Anesthesiologists physical status (ASA-PS) 3/4 were significant risk factors for postoperative aggravation of the ODI-8. Factor analysis revealed that the ODQ was composed of dynamic and static activities; the ODI-8 was considered a dynamic activity.

CONCLUSION

Almost a fourth of the patients skipped the ODI-8. Age, the presence of spinal deformity, and worse ASA-PS were found to be risk factors for postoperative aggravation of sexual function.

LEVEL OF EVIDENCE I

Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Validity of the Japanese core outcome measures index (COMI)-neck for cervical spine surgery: a prospective cohort study

PURPOSE

To investigate the psychometric properties of the Japanese version of the Core Outcome Measures Index-Neck (COMI-Neck) in patients undergoing cervical spine surgery.

METHODS

A total of 177 patients undergoing cervical spine surgery for spinal disorders from April to December 2017 were enrolled. Patient-reported outcomes (PROs) included EuroQOL, Neck Disability Index, and treatment satisfaction. To address whether the questionnaire's scores relate to other outcomes based on a predefined hypothesis, the correlations between the COMI-Neck and the other PROs were measured (Spearman's rank correlation coefficients). The minimum clinically important difference (MCID) of the COMI summary score was calculated using the receiver operating characteristic (ROC) curve with a 7-point Likert scale of satisfaction with the treatment results. To assess reproducibility, another group of 59 volunteers with chronic neck pain were asked to reply to the COMI-Neck twice with an interval of 7-14 days.

RESULTS

The COMI summary score showed no floor or ceiling effects preoperatively or postoperatively. Each of the COMI domains and the COMI summary score correlated to the hypothesized extent with the scores of the reference questionnaires (ρ = 0.40-0.79). According to the ROC curve with satisfaction (including "very satisfied" and "satisfied"), the area under the curve and MCID of the COMI summary score were 0.78 and 2.1. The intraclass correlation coefficient and the minimum detectable change (MDC 95%) of the COMI summary score were 0.97 and 0.77.

CONCLUSION

The Japanese version of the COMI-Neck is valid and reliable for Japanese-speaking patients with cervical spinal disorders.

Validation study of a diagnostic scoring system for sacroiliac joint-related pain

Background

There are no specific radiological findings for the diagnosis of sacroiliac joint-related pain. A diagnostic scoring system had been developed in 2017. The score comprised the sum of scores of six items. The score ranged from 0 to 9 points, and the cutoff was calculated as 4.

Objective

To evaluate the validity of the diagnostic scoring system for sacroiliac joint-related pain.

Patients and methods

The sacroiliac joint-related pain group (n=31) comprised patients diagnosed with sacroiliac joint-related pain based on patient history, physical findings, and responses to analgesic periarticular injection. In addition, it was confirmed that they had no other lumbar or hip joint diseases. The non-sacroiliac joint-related pain group (n=123) comprised patients with low back pain due to a reason other than sacroiliac joint-related pain. We evaluated scores for all subjects. We analyzed the differences in each item between both groups and performed receiver-operating characteristic curve analysis to evaluate the score validity.

Results

There were no significant differences in patient characteristics between groups. There were significant differences for the following four of six items: one-finger test results (P<0.0001), pain while sitting on a chair (P=0.0141), sacroiliac joint shear test results (P<0.0001), and tenderness of the posterosuperior iliac spine (P<0.0001). The cut-off value was 5 points, the area under the curve was 0.80239, sensitivity was 77.4%, and specificity was 76.4%.

Conclusion

The score demonstrated moderate validity for diagnosing sacroiliac joint-related pain.

The associations between magnetic resonance imaging findings and low back pain: A 10-year longitudinal analysis

PURPOSE

To conduct a 10-year longitudinal analysis of the relationship between magnetic resonance imaging (MRI) findings and low back pain (LBP).

MATERIALS AND METHODS

Ninety-one volunteers with a history of LBP, but without current LBP were recruited between 2005 and 2006. Participants' baseline demographics and MRI findings were recorded. All volunteers were invited for a follow-up MRI in 2016; of these, 49 volunteers (53.8%) participated in the follow-up. We enquired whether they had LBP history during the 10 years between the baseline and follow-up examinations. Sagittal T1 and T2-weighted MRI were used to assess the intervertebral space from T12/L1 to L5/S1. We evaluated the presence of disc degeneration by Pfirrmann's grading system, disc bulging, high intensity zone (HIZ), spondylolisthesis, and any type of Modic changes in the follow-up MRIs. We compared the follow-up MRI findings with the baseline findings; the progress of each finding over the 10 years were also compared between the groups with (n = 36) and without (n = 13) LBP.

RESULTS

Average age of the study participants at follow-up was 44.8 years; 25 were female and 24 were male. Average age, sex, body mass index, and smoking habits of those who did and did not participate in the follow-up study, as well as the demographic characteristics of those who did and did not have LBP history during the 10 years, were not significantly different. Compared with the group without LBP history, the group that had LBP history during the 10 years did not have a significantly increased prevalence of disc degeneration, disc bulging, and HIZ in the follow-up and baseline MRIs. Spondylolisthesis and any type of Modic changes were also not associated with LBP history during the 10 years.

CONCLUSIONS

Follow-up MRI findings consistent with Pfirrmann grading ≥4, disc bulging, HIZ, spondylolisthesis, and any type of Modic changes were not associated with LBP history during the 10 years between the baseline and follow-up study. The progresses of these findings were also not associated with the LBP history. In addition, baseline MRI findings were not associated with LBP history during the 10 years; therefore, our data suggest that baseline MRI findings cannot predict future LBP.

The relationship between findings on magnetic resonance imaging and previous history of low back pain

The objective of this study was to evaluate the relationship between magnetic resonance imaging (MRI) findings and previous low back pain (LBP) in participants without current LBP. Current LBP was defined as LBP during the past month. Previous LBP was defined as a history of medical consultation for LBP. Ninety-one participants without current LBP were included. Sagittal T2-weighted MRI was used to assess the intervertebral space from T12/L1 to L5/S1. These images were classified into five grades based on the Pfirrmann grading system. Furthermore, we evaluated the presence of disk bulging, high-intensity zone, and spondylolisthesis. We compared the MRI findings between groups with (27 participants) and without (64 participants) previous LBP without current LBP. Intraobserver and interobserver kappa values were evaluated. Participants had an average age of 34.9 years; 47 were female and 44 were male; and their average body mass index was 21.8 kg/m². Compared to the group of participants without previous LBP, the group of participants with previous LBP had a significantly higher incidence of disk degeneration such as a Pfirrmann grade ≥3, disk bulging, and high-intensity zone in the analyses adjusted by age and sex. There were no significant differences in spondylolisthesis between the groups. An odds ratio of >10 was only found for Pfirrmann grade ≥3, ie, a Pfirrmann grade ≥3 was strongly associated with a history of previous LBP in participants without current LBP.

Hypnotics Use and Falls in Hospital Inpatients Stratified by Age

<p><strong>BACKGROUND:</strong> Little is known about the association between hypnotics use and falls among inpatients in young and middle-aged populations. We aimed to determine whether the use of hypnotics elevated the fall risk in adult inpatients aged 20 and above.</p><p><strong>METHODS:</strong> Patients admitted to the Kanto Rosai Hospital, Kanagawa, Japan, between April 1, 2013 and January 31, 2014 were followed up until discharge. We estimated the incidence rate ratio (IRR) and 95% confidence intervals (CI) of falls for the use of hypnotic drugs with a Poisson regression model, adjusted for sex, age, activities of daily living, and comorbidities.</p><p><strong>RESULTS:</strong> For the 6,949 inpatients whose medical records were examined, the incidence of falls was significantly higher in hypnotics’ users than in non-users. The IRR was 1.52 (95% CI, 1.10-2.11). When stratified by age, the risk of hypnotics use in the patients aged 65 and above was statistically elevated (IRR, 1.48; 95% CI, 1.02-2.13); the risk in the patients aged 25-64 was elevated but not significant (IRR, 1.33; 95% CI, 0.63-2.81).</p><p><strong>CONCLUSION:</strong> Usage of hypnotics elevated fall risk in the older inpatients, though this association was not significant in the young and middle-aged inpatients. Further studies are needed.</p>

High pH-Sensitive TRPA1 Activation in Odontoblasts Regulates Mineralization

Calcium hydroxide and mineral trioxide aggregate are widely used for indirect and direct pulp capping and root canal filling. Their dissociation into Ca(2+) and OH(-) in dental pulp creates an alkaline environment, which activates reparative/reactionary dentinogenesis. However, the mechanisms by which odontoblasts detect the pH of the extracellular environment remain unclear. We examined the alkali-sensitive intracellular Ca(2+) signaling pathway in rat odontoblasts. In the presence or absence of extracellular Ca(2+), application of alkaline solution increased intracellular Ca(2+) concentration, or [Ca(2+)]i Alkaline solution-induced [Ca(2+)]i increases depended on extracellular pH (8.5 to 10.5) in both the absence and the presence of extracellular Ca(2+) The amplitude was smaller in the absence than in the presence of extracellular Ca(2+) Each increase in [Ca(2+)]i, activated by pH 7.5, 8.5, or 9.5, depended on extracellular Ca(2+) concentration; the equilibrium binding constant for extracellular Ca(2+) concentration decreased as extracellular pH increased (1.04 mM at pH 7.5 to 0.11 mM at pH 9.5). Repeated applications of alkaline solution did not have a desensitizing effect on alkali-induced [Ca(2+)]i increases and inward currents. In the presence of extracellular Ca(2+), alkaline solution-induced [Ca(2+)]i increases were suppressed by application of an antagonist of transient receptor potential ankyrin subfamily member 1 (TRPA1) channels. Ca(2+) exclusion efficiency during alkaline solution-induced [Ca(2+)]i increases was reduced by a Na(+)-Ca(2+) exchanger antagonist. Alizarin red and von Kossa staining revealed increased mineralization levels under repeated high pH stimulation, whereas the TRPA1 antagonist strongly reduced this effect. These findings indicate that alkaline stimuli-such as the alkaline environment inside dental pulp treated with calcium hydroxide or mineral trioxide aggregate-activate Ca(2+) mobilization via Ca(2+) influx mediated by TRPA1 channels and intracellular Ca(2+) release in odontoblasts. High pH-sensing mechanisms in odontoblasts are important for activating dentinogenesis induced by an alkaline environment.

Anterior screw fixation for an odontoid fracture using an Acutrak 4/5 screw: a case report

The direct anterior screw fixation of odontoid fractures by a single cancellous screw, especially for osteoporotic vertebrae, has a potential risk of leading to insufficient stability and implant failures. We experienced good results following surgery using a single Acutrak 4/5 screw to obtain sufficient stability for an odontoid fracture in a patient with osteopenia. The screw is a cannulated self-tapping headless screw and has a tapered profile and full threads with variable pitches, and it can yield sufficient compression force as the screw is inserted. The preoperative severe neck pain of the patient was diminished immediately after the surgery. The patient achieved bone union in a short time and had a good clinical result for at least 3 years. Some biomechanical studies showed that the compression force of Acutrak standard screws was stronger than that of both 4.0-mm cancellous screws inserted with the lag screw technique and Herbert screws, and other studies showed that the compression force of Acutrak 4/5 screws was equivalent to that of 4.5-mm cortical screws. However, there has been no clinical report of surgery using an Acutrak 4/5 screw for odontoid fractures. This is the first clinical report of fixation by an Acutrak 4/5 screw.

Hormonal therapy with external radiation therapy for metastatic spinal cord compression from newly diagnosed prostate cancer

BACKGROUND

Although hormonal therapy is effective for treatment of prostate cancer, its effect in the treatment of metastatic spinal cord compression (MSCC) has not been established. The objective of this study was to clarify the efficacy of conservative treatment of MSCC-induced paralysis resulting from prostate cancer for patients without a previous treatment history.

METHODS

We reviewed data from 38 patients with MSCC-induced paralysis from newly diagnosed prostate cancer who presented to our service between 1984 and 2010. Conservative treatment consisted of hormonal therapy with external radiation therapy (ERT). Patient demographic data, treatment details, involved spine MRI images, complications, and the course of neurologic recovery were investigated.

RESULTS

Twenty-five patients were treated conservatively. Mean follow-up period was 36.8 months. Sixteen patients (two with Frankel B, 14 with Frankel C) were unable to walk at initial presentation. After initiating conservative treatment, 75% (12 of 16) of these patients regained the ability to walk within 1 month, 88% (14 in 16) did so within 3 months, and all non-ambulatory patients did so within 6 months. No one had morbid complications. Four patients who did not regain the ability to walk at 1 month were found to have progressed to paraplegia rapidly, and tended to have severe compression as visualized on MRI, with a delay in the start of treatment in comparison with those who did so within 1 month (21.0 vs. 7.8 days).

CONCLUSIONS

Hormonal therapy associated with ERT is an important option for treatment of MSCC resulting from newly diagnosed prostate cancer.

Mechanisms underlying catabolic and anabolic functions of parathyroid hormone on bone by combination of culture systems of mouse cells

Since bone resorption and formation by continuous and intermittent parathyroid hormone (PTH) treatments involve various types of cells in bone, this study examined the underlying mechanism by combining culture systems using mouse primary calvarial osteoblasts and bone marrow cells. The PTH/PTHrP receptor (PTH1R) expression and the cAMP accumulation in response to PTH were increased in accordance with the differentiation of osteoblasts. Osteoclast formation was strongly induced by continuous PTH treatment in the monolayer co-culture of osteoblasts and bone marrow cells, which was associated with RANKL expression in differentiated osteoblasts. Bone formation determined by ALP activity and the type I collagen mRNA expression was stimulated by intermittent PTH treatment in the monolayer co-culture and in the bone marrow cell layer of the separated co-culture in a double chamber dish, but not in the culture of bone marrow cells alone. The stimulation in the separated co-culture, accompanied by IGF-I production by osteoblasts, was abolished when bone marrow cells were derived from knockout mice of insulin-receptor substrate-1 (IRS-1-/-) or when osteoblasts were from PTH1R-/- mice. We conclude that differentiated osteoblasts are most likely the direct target of both continuous and intermittent PTH, while bone marrow cells are likely the effector cells. The osteoblasts stimulated by continuous PTH express RANKL which causes osteoclastogenesis from the precursors in bone marrow via cell-to-cell contact, leading to bone resorption; while the osteoblasts stimulated by intermittent PTH secrete IGF-I which activates IRS-1 in osteoblast precursors in bone marrow via a paracrine mechanism, leading to bone formation.

Transcriptional induction of SOX9 by NF-kappaB family member RelA in chondrogenic cells

OBJECTIVE

Although SOX9 is a key molecule for chondrogenic differentiation, little is known about the upstream signal. The present study attempted to identify transcription factors to induce SOX9 expression and examined the mechanism.

METHODS

Sequences of about 1 kb of 5'-end flanking regions were compared between human and mouse SOX9 genes. In vivo localization was examined by immunohistochemistry in the limb cartilage of fetal mice. Promoter activities of the SOX9, SOX6, and type II collagen (COL2A1) genes were determined in human non-chondrogenic HeLa cells and mouse chondrogenic ATDC5 cells transfected with a luciferase-reporter gene containing the promoter fragments. Protein-DNA binding was examined by electrophoretic mobility shift and chromatin immunoprecipitation assays. The chondrogenic differentiation was assessed by endogenous SOX9, SOX6, and COL2A1 mRNA levels, and by Alcian blue staining and alkaline phosphatase activity.

RESULTS

Among transcription factors whose binding motifs were identified in the highly-conserved regions between human and mouse SOX9 promoters, a nuclear factor kappa B (NF-kappaB) member RelA strongly activated the promoter activity. RelA and SOX9 were co-localized in the limb cartilage. Deletion, mutagenesis, and tandem-repeat analyses identified the core region responsive to RelA at the NF-kappaB binding motif to be around -250bp of the human SOX9 promoter, and this was confirmed to show specific binding to RelA. RelA induced the chondrogenic differentiation parameters in HeLa and ATDC5 cells.

CONCLUSION

We have identified RelA as a transcriptional factor for SOX9 induction and chondrogenic differentiation via binding to an NF-kappaB binding motif in the SOX9 promoter.

Phosphorylation of GSK-3beta by cGMP-dependent protein kinase II promotes hypertrophic differentiation of murine chondrocytes

cGMP-dependent protein kinase II (cGKII; encoded by PRKG2) is a serine/threonine kinase that is critical for skeletal growth in mammals; in mice, cGKII deficiency results in dwarfism. Using radiographic analysis, we determined that this growth defect was a consequence of an elongated growth plate and impaired chondrocyte hypertrophy. To investigate the mechanism of cGKII-mediated chondrocyte hypertrophy, we performed a kinase substrate array and identified glycogen synthase kinase-3beta (GSK-3beta; encoded by Gsk3b) as a principal phosphorylation target of cGKII. In cultured mouse chondrocytes, phosphorylation-mediated inhibition of GSK-3beta was associated with enhanced hypertrophic differentiation. Furthermore, cGKII induction of chondrocyte hypertrophy was suppressed by cotransfection with a phosphorylation-deficient mutant of GSK-3beta. Analyses of mice with compound deficiencies in both protein kinases (Prkg2(-/-)Gsk3b(+/-)) demonstrated that the growth retardation and elongated growth plate associated with cGKII deficiency were partially rescued by haploinsufficiency of Gsk3b. We found that beta-catenin levels decreased in Prkg2(-/-) mice, while overexpression of cGKII increased the accumulation and transactivation function of beta-catenin in mouse chondroprogenitor ATDC5 cells. This effect was blocked by coexpression of phosphorylation-deficient GSK-3beta. These data indicate that hypertrophic differentiation of growth plate chondrocytes during skeletal growth is promoted by phosphorylation and inactivation of GSK-3beta by cGKII.

Kruppel-like factor 5 causes cartilage degradation through transactivation of matrix metalloproteinase 9

Although degradation of cartilage matrix has been suggested to be a rate-limiting step for endochondral ossification during skeletal development, little is known about the transcriptional regulation. This study investigated the involvement of KLF5 (Krüppel-like factor 5), an Sp/KLF family member, in the skeletal development. KLF5 was expressed in chondrocytes and osteoblasts but not in osteoclasts. The heterozygous deficient (KLF5+/-) mice exhibited skeletal growth retardation in the perinatal period. Although chondrocyte proliferation and differentiation were normal, cartilage matrix degradation was impaired in KLF5+/- mice, causing delay in replacement of cartilage with bone at the primary ossification center in the embryonic limbs and elongation of hypertrophic chondrocyte layer in the neonatal growth plates. Microarray analyses identified MMP9 (matrix metalloproteinase 9) as a transcriptional target, since it was strongly up-regulated by adenoviral transfection of KLF5 in chondrogenic cell line OUMS27. The KLF5 overexpression caused gelatin degradation by stimulating promoter activity of MMP9 without affecting chondrocyte differentiation or vascular endothelial growth factor expression in the culture of chondrogenic cells; however, in osteoclast precursors, it affected neither MMP9 expression nor osteoclastic differentiation. KLF5 dysfunction by genetic heterodeficiency or RNA interference was confirmed to cause reduction of MMP9 expression in cultured chondrogenic cells. MMP9 expression was decreased in the limbs of KLF5+/- embryos, which was correlated with suppression of matrix degradation, calcification, and vascularization. We conclude that KLF5 causes cartilage matrix degradation through transcriptional induction of MMP9, providing the first evidence that transcriptional regulation of a proteinase contributes to endochondral ossification and skeletal development.

Neurologic level diagnosis of cervical stenotic myelopathy

STUDY DESIGN

A cross-sectional analysis.

OBJECTIVE

To elucidate the accuracy of neurologic level diagnosis of cervical stenotic myelopathy.

SUMMARY OF BACKGROUND DATA

Neurologic level diagnosis in cervical myelopathy has not been well established.

METHODS

A total of 106 patients with cervical stenotic myelopathy, with a single-level intramedullary high-intensity area confirmed on both preoperative and postoperative T2-weighted magnetic resonance imaging (MRI), were included in this study. We performed a level diagnosis on the basis of neurologic signs (the uppermost muscle with weakness, diminished or exaggerated deep tendon reflex, the uppermost level of sensory disturbance of the upper extremities) and compared it with a level diagnosis made by T2-weighted MRI. The sensitivity, specificity, and accuracy of neurologic signs on our index corresponding to each intervertebral level were calculated.

RESULTS

The averages of sensitivity, specificity, and accuracy were 42%, 80%, and 70%, respectively, in the uppermost muscle with weakness, 66%, 89%, and 83% in deep tendon reflex, and 74%, 91%, and 87% in the sensory disturbance area. The positive and negative predictive values were 40% and 91%, respectively, in the uppermost muscle with weakness, 66% and 89% in deep tendon reflex, and 74% and 91% in the sensory disturbance area. Accuracy of a diagnosis based on muscle weakness was less high, the reason being that in many patients, the uppermost muscle with weakness was extensor digiti communis or the intrinsic muscles of the hands, and this led to a lower sensitivity.

CONCLUSIONS

The average accuracy of neurologic level diagnosis based on the index we proposed was > or =70%. The level diagnosis by a sensory disturbance area showed the highest accuracy (87%).

[Interactions of chondrocytes and osteoblasts during endochondral bone formation]

During endochondral bone formation, mesenchymal condensations, chondrocyte differentiation and proliferation, termination of proliferation, hypertrophic differentiation, and replacement by bone occur sequentially. This sequence is spatially represented by the structure of the growth plate of the embryo, and reflects the evolution of bone. Endochondral bone formation is mainly regulated by the interactions of chondrocytes and osteoblasts; a variety of signals are implicated in this regulation. The roles of factors regulating chondrocyte proliferation and hypertrophy including the Sox trio, PTH related peptide (PTHrP), Indian hedgehog (Ihh), the runt-related transcription factor (Runx) family, fibroblast growth factor receptor 3 (FGFR3) and bone morphogenetic protein (BMP) and other factors including hypoxia-inducible factor 1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) will be discussed.

Image-guided surgery for thoracic ossification of the posterior longitudinal ligament. Technical note

The authors describe an anterior decompression procedure for thoracic ossification of the posterior longitudinal ligament (PLL) in which they used an image guidance system in three cases. To make registration possible in anterior thoracic surgery, they devised a surgical reference frame that could be connected to a rod and attached to an external fixation device, which was then attached to the thoracic VB. The mean fiducial error at the registration was acceptable (range 0.5-0.8 mm). They were able to confirm the success of decompression on postoperative computerized tomography scans. In the removal of an ossified thoracic PLL, an image guidance system has been shown to be a useful tool.

Validity and reliability of SRSI and SF-36 in Japanese patients with scoliosis

We have examined the validity and reliability of Japanese SRS-24 and SF-36 in patients with scoliosis. 278 patients with scoliosis were recruited. Their average age was 24.8 years (range 17-84 years) and 83% of patients had idiopathic curves. The major coronal curve averaged 43 degrees (range 10 degrees -114 degrees). Questionnaires surveyed were SRS-24 and SRS-22, and SF-36. Only domains applicable to untreated patients were analyzed. Scale level analysis was evaluated by the ceiling and floor effect. The Cronbach alpha and item-scale correlations were calculated as representatives of internal consistency reliability and item internal consistency, respectively. Most domains of SF-36 had large ceiling effects. Both the SRS questionnaires had limited ceiling/floor effects. SRS-22 had a better internal consistency than SRS-24. Low item-scale correlations (<0.25) were found in question 14, 15, and 18 of SRS-22. The Japanese version of SRS-22 was the most useful measure for patients with scoliosis. However, some questions have low item-scale correlations, lowering reliability of the Function domain.

Correction of scoliosis using segmental pedicle screw instrumentation versus hybrid constructs with hooks and screws

Eighteen consecutive patients with scoliosis surgically treated by posterior correction and fusion were recruited. The major coronal curve averaged 65.8 degrees (range 51 degrees -87 degrees ). Eight patients were treated by hybrid constructs and four of them had anterior release before posterior surgery. Ten patients were treated by posterior correction and fusion alone with pedicle screw instrumentation. Flexibility was assessed by radiographs using the active bending and the fulcrum bending techniques. Two correction indices were not statistically different between the two groups. However, there was a tendency towards better correction in the screw group: mean surgical correction was 62.6+/-11.8% in the hook group and 71.6+/-12.3% in the screw group (p=0.07). Comparable pre- and post-operative radiographic results may indicate the advantages of posterior-only segmental pedicle screw instrumentation over hybrid constructs.