Efficacy of D-Wave Monitoring Combined With the Transcranial Motor-Evoked Potentials in High-Risk Spinal Surgery: A Retrospective Multicenter Study of the Monitoring Committee of the Japanese Society for Spine Surgery and Related Research

STUDY DESIGN

Retrospective multicenter cohort study.

OBJECTIVES

We aimed to clarify the efficacy of multimodal intraoperative neuromonitoring (IONM), especially in transcranial electrical stimulation of motor-evoked potentials (TES-MEPs) with spinal cord-evoked potentials after transcranial stimulation of the brain (D-wave) in the detection of reversible spinal cord injury in high-risk spinal surgery.

METHODS

We reviewed 1310 patients who underwent TES-MEPs during spinal surgery at 14 spine centers. We compared the monitoring results of TES-MEPs with D-wave vs TES-MEPs without D-wave in high-risk spinal surgery.

RESULTS

There were 40 cases that used TES-MEPs with D-wave and 1270 cases that used TES-MEPs without D-wave. Before patients were matched, there were significant differences between groups in terms of sex and spinal disease category. Although there was no significant difference in the rescue rate between TES-MEPs with D-wave (2.0%) and TES-MEPs (2.5%), the false-positivity rate was significantly lower (0%) in the TES-MEPs-with-D-wave group. Using a one-to-one propensity score-matched analysis, 40 pairs of patients from the two groups were selected. Baseline characteristics did not significantly differ between the matched groups. In the score-matched analysis, one case (2.5%) in both groups was a case of rescue (P = 1), five (12.5%) cases in the TES-MEPs group were false positives, and there were no false positives in the TES-MEPs-with-D-wave group (P = .02).

CONCLUSIONS

TES-MEPs with D-wave in high-risk spine surgeries did not affect rescue case rates. However, it helped reduce the false-positivity rate.

Role of Transcranial Motor Evoked Potential Monitoring During Traumatic Spinal Injury Surgery: A Prospective Multicenter Study of the Monitoring Committee of the Japanese Society for Spine Surgery and Related Research

STUDY DESIGN

A prospective multicenter observational cohort study.

OBJECTIVE

This study aimed to investigate the role of transcranial motor evoked potential (TcMEP) monitoring during traumatic spinal injury surgery, the timing of TcMEP alerts, and intervention strategies to avoid intraoperative neurological complications.

SUMMARY OF BACKGROUND DATA

Intraoperative neuromonitoring, including TcMEP monitoring, is commonly used in high-risk spinal surgery to predict intraoperative spinal cord injury; however, little information is available on its use in traumatic spinal injury surgery.

METHODS

The TcMEP monitoring data of 350 consecutive patients who underwent traumatic spinal injury surgery (mean age, 69.3 y) between 2017 and 2021 were prospectively reviewed. In this study, a TcMEP amplitude reduction ≥70% was established as a TcMEP alert. A rescue case was defined as a case with the recovery of TcMEP amplitudes after certain procedures and without postoperative neurological complications.

RESULTS

Among the 350 patients who underwent traumatic spinal injury surgery (TcMEP derivation rate 94%), TcMEP monitoring revealed seven true-positive (TP) (2.0%), three rescues (0.9%; rescue rate 30%), 31 false-positive, one false-negative, and 287 true-negative cases, resulting in 88% sensitivity, 90% specificity, 18% positive predictive value, and 99% negative predictive value. The TP rate in patients with preoperative motor deficits was 2.9%, which was higher than that in patients without preoperative motor deficits (1.1%). The most common timing of TcMEP alerts was during decompression (40%). During decompression, suspension of surgery with intravenous steroid injection was ineffective (rescue rate, 0%), and additional decompression was effective.

CONCLUSION

Given the low prevalence of neurological complications (2.3%) and the low positive predictive value (18.4%), single usage of TcMEP monitoring during traumatic spinal injury surgery is not recommended. Further efforts should be made to reduce FP alert rates through better interpretation of multimodal Intraoperative neuromonitorings and the incorporation of anesthesiology to improve the positive predictive value.

LEVEL OF EVIDENCE

3.

Impact of Preoperative Motor Status for the Positive Predictive Value of Transcranial Motor-Evoked Potentials Alerts in Thoracic Spine Surgery: A Prospective Multicenter Study by the Monitoring Committee of the Japanese Society for Spine Surgery and Related Research

STUDY DESIGN

Prospective multicenter study.

OBJECTIVE

To investigate the validity of transcranial motor-evoked potentials (Tc-MEP) in thoracic spine surgery and evaluate the impact of specific factors associated with positive predictive value (PPV).

METHODS

One thousand hundred and fifty-six cases of thoracic spine surgeries were examined by comparing patient backgrounds, disease type, preoperative motor status, and Tc-MEP alert timing. Tc-MEP alerts were defined as an amplitude decrease of more than 70% from the baseline waveform. Factors were compared according to preoperative motor status and the result of Tc-MEP alerts. Factors that showed significant differences were identified by univariate and multivariate analysis.

RESULTS

Overall sensitivity was 91.9% and specificity was 88.4%. The PPV was significantly higher in the preoperative motor deficits group than in the preoperative no-motor deficits group for both high-risk (60.3% vs 38.3%) and non-high-risk surgery groups (35.1% vs 12.8%). In multivariate logistic analysis, the significant factors associated with true positive were surgical maneuvers related to ossification of the posterior longitudinal ligament (odds ratio = 11.88; 95% CI: 3.17-44.55), resection of intradural intramedullary spinal cord tumor (odds ratio = 8.83; 95% CI: 2.89-27), preoperative motor deficit (odds ratio = 3.46; 95% CI: 1.64-7.3) and resection of intradural extramedullary spinal cord tumor (odds ratio = 3.0; 95% CI: 1.16-7.8). The significant factor associated with false positive was non-attributable alerts (odds ratio = .28; 95% CI: .09-.85).

CONCLUSION

Surgeons are strongly encouraged to use Tc-MEP in patients with preoperative motor deficits, regardless of whether they are undergoing high-risk spine surgery or not. Knowledge of PPV characteristics will greatly assist in effective Tc-MEP enforcement and minimize neurological complications with appropriate interventions.

Comparison of intraoperative neuromonitoring accuracies and procedures associated with alarms in anterior versus posterior fusion for cervical spinal disorders: A prospective multi-institutional cohort study

A prospective multicenter cohort study. To clarify the differences in the accuracy of transcranial motor-evoked potentials (TcE-MEPs) and procedures associated with the alarms between cervical anterior spinal fusion (ASF) and posterior spinal fusion (PSF). Neurological complications after TcE-MEP alarms have been prevented by appropriate interventions for cervical degenerative disorders. The differences in the accuracy of TcE-MEPs and the timing of alarms between cervical ASF and PSF noted in the existing literature remain unclear. Patients (n = 415) who underwent cervical ASF (n = 171) or PSF (n = 244) at multiple institutions for cervical spondylotic myelopathy, ossification of the posterior longitudinal ligament, spinal injury, and others were analyzed. Neurological complications, TcE-MEP alarms defined as a decreased amplitude of ≤70% compared to the control waveform, interventions after alarms, and TcE-MEP results were compared between the 2 surgeries. The incidence of neurological complications was 1.2% in the ASF group and 2.0% in the PSF group, with no significant intergroup differences (P-value was .493). Sensitivity, specificity, negative predictive value, and rate of rescue were 50.0%, 95.2%, 99.4%, and 1.8%, respectively, in the ASF group, and 80.0%, 90.9%, 99.5%, and 2.9%, respectively, in the PSF group. The accuracy of TcE-MEPs was not significantly different between the 2 groups (P-value was .427 in sensitivity, .109 in specificity, and .674 in negative predictive value). The procedures associated with the alarms were decompression in 3 cases and distraction in 1 patient in the ASF group. The PSF group showed Tc-MEPs decreased during decompression, mounting rods, turning positions, and others. Most alarms went off during decompression in ASF, whereas various stages of the surgical procedures were associated with the alarms in PSF. There were no significant differences in the accuracy of TcE-MEPs between the 2 surgeries.

The Utility of Transcranial Stimulated Motor-Evoked Potential Alerts in Cervical Spine Surgery Varies Based on Preoperative Motor Status

STUDY DESIGN

A prospective multicenter observational study.

OBJECTIVE

The aim was to investigate the validity of transcranial motor-evoked potentials (Tc-MEP) in cervical spine surgery and identify factors associated with positive predictive value when Tc-MEP alerts are occurred.

SUMMARY OF BACKGROUND DATA

The sensitivity and specificity of Tc-MEP for detecting motor paralysis are high; however, false-positives sometimes occur.

MATERIALS AND METHODS

The authors examined Tc-MEP in 2476 cases of cervical spine surgeries and compared patient backgrounds, type of spinal disorders, preoperative motor status, surgical factors, and the types of Tc-MEP alerts. Tc-MEP alerts were defined as an amplitude reduction of more than 70% from the control waveform. Tc-MEP results were classified into two groups: false-positive and true-positive, and items that showed significant differences were extracted by univariate analysis and detected by multivariate analysis.

RESULTS

Overall sensitivity was 66% (segmental paralysis: 33% and lower limb paralysis: 95.8%) and specificity was 91.5%. Tc-MEP outcomes were 33 true-positives and 233 false-positives. Positive predictive value of general spine surgery was significantly higher in cases with a severe motor status than in a nonsevere motor status (19.5% vs . 6.7%, P =0.02), but not different in high-risk spine surgery (20.8% vs . 19.4%). However, rescue rates did not significantly differ regardless of motor status (48% vs . 50%). In a multivariate logistic analysis, a preoperative severe motor status [ P =0.041, odds ratio (OR): 2.46, 95% confidence interval (95% CI): 1.03-5.86] and Tc-MEP alerts during intradural tumor resection ( P <0.001, OR: 7.44, 95% CI: 2.64-20.96) associated with true-positives, while Tc-MEP alerts that could not be identified with surgical maneuvers ( P =0.011, OR: 0.23, 95% CI: 0.073-0.71) were associated with false-positives.

CONCLUSION

The utility of Tc-MEP in patients with a preoperative severe motor status was enhanced, even in those without high-risk spine surgery. Regardless of the motor status, appropriate interventions following Tc-MEP alerts may prevent postoperative paralysis.

Transcranial Motor-evoked Potentials for Intraoperative Nerve Root Monitoring During Adult Spinal Deformity Surgery: A Prospective Multicenter Study

STUDY DESIGN

A prospective, multicenter study.

OBJECTIVE

This study clarified the uses and limitations of transcranial motor-evoked potentials (Tc-MEPs) for nerve root monitoring during adult spinal deformity (ASD) surgeries.

SUMMARY OF BACKGROUND DATA

Whether Tc-MEPs can detect nerve root injuries (NRIs) in ASD surgeries remains controversial.

MATERIALS AND METHODS

We prospectively analyzed neuromonitoring data from 14 institutions between 2017 and 2020. The subjects were ASD patients surgically treated with posterior corrective fusion using multichannel Tc-MEPs. An alert was defined as a decrease of ≥70% in the Tc-MEP's waveform amplitude from baseline, and NRI was considered as meeting the focal Tc-MEP alerts shortly following surgical procedures with postoperative nerve root symptoms in the selected muscles.

RESULTS

A total of 311 patients with ASD (262 women and 49 men) and a mean age of 65.5 years were analyzed. Tc-MEP results revealed 47 cases (15.1%) of alerts, including 25 alerts after 10 deformity corrections, six three-column osteotomies, four interbody fusions, three pedicle screw placements or two decompressions, and 22 alerts regardless of surgical maneuvers. Postoperatively, 14 patients (4.5%) had neurological deterioration considered to be all NRI, 11 true positives, and three false negatives (FN). Two FN did not reach a 70% loss of baseline (46% and 65% loss of baseline) and one was not monitored at target muscles. Multivariate logistic regression analysis revealed that risk factors of NRI were preexisting motor weakness ( P <0.001, odds ratio=10.41) and three-column osteotomies ( P =0.008, odds ratio=7.397).

CONCLUSIONS

Nerve root injuries in our ASD cohort were partially predictable using multichannel Tc-MEPs with a 70% decrease in amplitude as an alarm threshold. We propose that future research should evaluate the efficacy of an idealized warning threshold (e.g., 50%) and a more detailed evoked muscle selection, in reducing false negatives.

Current Trends in Intraoperative Spinal Cord Monitoring: A Survey Analysis among Japanese Expert Spine Surgeons

Introduction

Although intraoperative spinal neuromonitoring (IONM) is recommended for spine surgeries, there are no guidelines regarding its use in Japan, and its usage is mainly based on the surgeon's preferences. Therefore, this study aimed to provide an overview of the current trends in IONM usage in Japan.

Methods

In this web-based survey, expert spine surgeons belonging to the Japanese Society for Spine Surgery and Related Research were asked to respond to a questionnaire regarding IONM management. The questionnaire covered various aspects of IONM usage, including the preferred modality, operation of IONM, details regarding muscle-evoked potential after electrical stimulation of the brain (Br(E)-MsEP), and need for consistent use of IONM in major spine surgeries.

Results

Responses were received from 134 of 186 expert spine surgeons (response rate, 72%). Of these, 124 respondents used IONM routinely. Medical staff rarely performed IONM without a medical doctor. Br(E)-MsEP was predominantly used for IONM. One-third of the respondents reported complications, such as bite injuries caused by Br(E)-MsEP. Interestingly, two-thirds of the respondents did not plan responses to alarm points. Intramedullary spinal cord tumor, scoliosis (idiopathic, congenital, or neuromuscular in pediatric), and thoracic ossification of the posterior longitudinal ligament were representative diseases that require IONM.

Conclusions

IONM has become an essential tool in Japan, and Br(E)-MsEP is a predominant modality for IONM at present. Although we investigated spine surgeries for which consistent use of IONM is supported, a cost-benefit analysis may be required.

Risk factors for early-onset radiographical adjacent segment disease in patients with spondylolytic spondylolisthesis after single-level posterior lumbar interbody fusion

BACKGROUND CONTEXT

The risk factors for radiographical adjacent segment disease (ASD) in patients with degenerative spondylolisthesis have been previously reported. However, there are only few reports on patients with spondylolytic spondylolisthesis who underwent single-level posterior lumbar interbody fusion (PLIF).

PURPOSE

The study aimed to investigate the risk factors for radiographical ASD in patients with L5-S1 spondylolytic spondylolisthesis who underwent single-level PLIF.

STUDY DESIGN/SETTING

A retrospective study PATIENT SAMPLE: This study retrospectively reviewed 135 consecutive patients (91 men and 44 women) with symptomatic L5-S1 spondylolytic spondylolisthesis who underwent single-level PLIF.

OUTCOME MEASURES

The pre- and postoperative (at the final follow-up) spinopelvic parameters, % slip, sacral slope, lumbar lordosis (LL), pelvic tilt, pelvic incidence (PI), PI minus LL (PI - LL), lumbosacral angle, C7 sagittal vertical axis, and thoracic kyphosis were measured using standing radiographs.

METHODS

Radiographical ASD was defined as disc height loss (>3 mm), increase of posterior angulation (>5°), or progression of spondylolisthesis (>3 mm) between the pre- and postoperative radiographs. Pfirrmann's classification was used to evaluate disc degeneration. The radiographical parameters and changes between the pre- and postoperative values were evaluated and compared for the non-ASD and ASD groups. Binary logistic regression analysis was performed to evaluate the adjusted associations between each potential explanatory variable and ASD development.

RESULTS

The radiographical ASD incidence was 11%. Additionally, 60% of the patients with ASD had radiographical ASD at 1 year and all cases of radiographical ASD in this follow-up period occurred within 3 years after the initial surgery. The mean period of ASD occurrence after initial surgery was 21.7 ± 12.6 months. No patients required reoperation for radiographical ASD. Multivariate analysis revealed that a preoperative (odds ratio [OR], 5.9; 95% confidence interval [CI], 1.2-28.9; p=.03) and a postoperative (OR, 6.5; 95% CI, 1.2-34.5; p=.03) PI - LL of ≥15° were risk factors for radiographical ASD.

CONCLUSIONS

Pre- and postoperative PI - LL value mismatch was identified as significant independent risk factors for radiographical ASD in patients with L5-S1 spondylolytic spondylolisthesis. Obtaining larger lordosis at L5-S1 may be the key to preventing radiographical ASD.

Efficacy of Intraoperative Neuromonitoring Using Transcranial Motor-Evoked Potentials for Degenerative Cervical Myelopathy: A Prospective Multicenter Study by the Monitoring Committee of the Japanese Society for Spine Surgery and Related Research

STUDY DESIGN

A prospective multicenter observational study.

OBJECTIVE

To elucidate the efficacy of transcranial motor-evoked potentials (Tc(E)-MEPs) in degenerative cervical myelopathy (DCM) surgery by comparing cervical spondylotic myelopathy (CSM) to cervical ossification of the posterior longitudinal ligament (OPLL) and investigate the timing of Tc(E)-MEPs alerts and types of interventions affecting surgical outcomes.

SUMMARY OF BACKGROUND DATA

Although CSM and OPLL are the most commonly encountered diseases of DCM, the benefits of Tc(E)-MEPs for DCM remain unclear and comparisons of these two diseases have not yet been conducted.

METHODS

We examined the results of Tc(E)-MEPs from 1176 DCM cases (840 CSM /336 OPLL) and compared patients background by disease, preoperative motor deficits, and the type of surgical procedure. We also assessed the efficacy of interventions based on Tc(E)-MEPs alerts. Tc(E)-MEPs alerts were defined as an amplitude reduction of more than 70% below the control waveform. Rescue cases were defined as those in which waveform recovery was achieved after interventions in response to alerts and no postoperative paralysis.

RESULTS

Overall sensitivity was 57.1%, and sensitivity was higher with OPLL (71.4%) than with CSM (42.9%). The sensitivity of acute onset segmental palsy including C5 palsy was 40% (OPLL/CSM: 66.7%/0%) whereas that of lower limb palsy was 100%. The most common timing of Tc(E)-MEPs alerts was during decompression (63.16%), followed by screw insertion (15.79%). The overall rescue rate was 57.9% (OPLL/CSM: 58.3%/57.1%).

CONCLUSION

Since Tc(E)-MEPs are excellent for detecting long tract injuries, surgeons need to consider appropriate interventions in response to alerts. The detection of acute onset segmental palsy by Tc(E)-MEPs was partially possible with OPLL, but may still be difficult with CSM. The rescue rate was higher than 50% and appropriate interventions may have prevented postoperative neurological complications.Level of Evidence: 3.

Current progress of rehabilitative strategies in stem cell therapy for spinal cord injury: a review

Stem cell-based regenerative therapy has opened an avenue for functional recovery of patients with spinal cord injury (SCI). Regenerative rehabilitation is attracting wide attention owing to its synergistic effects, feasibility, non-invasiveness, and diverse and systemic properties. In this review article, we summarize the features of rehabilitation, describe the mechanism of combinatorial treatment, and discuss regenerative rehabilitation in the context of SCI. Although conventional rehabilitative methods have commonly been implemented alone, especially in studies of acute-to-subacute SCI, the combinatorial effects of intensive and advanced methods, including various neurorehabilitative approaches, have also been reported. Separating the concept of combined rehabilitation from regenerative rehabilitation, we suggest that the main roles of regenerative rehabilitation can be categorized as conditioning/reconditioning, functional training, and physical exercise, all of which are indispensable for enhancing functional recovery achieved using stem cell therapies.

Impact of leg numbness on patient satisfaction following decompression surgery for lumbar spinal stenosis

Decompression surgery is the most common surgical treatment for lumbar spinal stenosis (LSS). Relatively low satisfaction rate was reported. Patients often complaint of residual numbness despite significant pain relief. We hypothesized that numbness had a significant impact on patient satisfaction, but had not been evaluated, which is associated with low satisfaction rate. This study aimed to examine how much numbness is associated with patient satisfaction. We retrospectively reviewed prospectively collected data from consecutive patients who underwent decompression without fusion for LSS. We evaluated the Numeric Rating Scale (NRS) scores of low back pain (LBP), leg pain, and leg numbness preoperatively and at the final follow-up visit. Improvement was evaluated using minimum clinically important differences (MCIDs). Patient satisfaction was evaluated using the question, "How satisfied are you with the overall result of your back operation?". There are four possible answers consisting of "very satisfied (4-point)", "somewhat satisfied (3-point)", "somewhat dissatisfied (2-point)", or "very dissatisfied (1-point)". Spearman correlation was used to evaluate the association between patient satisfaction and reaching MCIDs. A total of 116 patients were included. All three components had correlation with patient satisfaction with the correlation efficient of 0.30 in LBP, 0.22 in leg pain, and 0.33 in numbness. Numbness had greatest correlation efficient value. We showed that numbness has a greater impact than leg/back pain on patient satisfaction in patients undergoing decompression for LSS. We suggest not only LBP and leg pain but also numbness should be evaluated pre- and postoperatively.

Understanding the effect of non-surgical factors in a transcranial motor-evoked potential alert: A retrospective cohort study

BACKGROUND

Intraoperative neuromonitoring (IONM) is important for detecting neurological dysfunction, allowing for intervention and reversal of neurological deficits before they become permanent. Of the several IONM modalities, transcranial electrical stimulation of motor-evoked potential (TES-MEP) can help monitor the activity in the pyramidal tract. Surgery- and non-surgery-related factors could result in a TES-MEP alert during surgery. Once the alert occurs, the surgeon should immediately intervene to prevent a neurological complication. However, TES-MEP monitoring does not provide sufficient data to identify the non-surgery-related factors. Therefore, this study aimed to identify and describe these factors among TES-MEP alert cases.

METHODS

In this multicenter study, data from 1934 patients who underwent various spinal surgeries for spinal deformities, spinal cord tumors, and ossification of the posterior longitudinal ligament of the spine from 2017 to 2019 were collected. A 70% amplitude reduction was set as the TES-MEP alarm threshold. All surgeries with alerts were categorized into true-positive (TP) and false-positive (FP) cases according to the assessment of immediate postoperative neurological deficits.

RESULTS

In total, TES-MEP alerts were observed in 251 cases during surgery: 62 TP and 189 FP IONM cases. Overall, 158 cases were related to non-surgery-related factors. We observed 22 (35.5%) TP cases and 136 (72%) FP cases, which indicated cases associated with non-surgery-related factors. A significant difference was observed between the two groups regarding factors associated with TES-MEP alerts (p < 0.01). The ratio of TP and FP cases (related to non-surgery-related factors) associated with TES-MEP alerts was 13.9% (22/158 cases) and 86.1% (136/158 cases), respectively.

CONCLUSIONS

Non-surgery-related factors are proportionally higher in FP than in TP cases. Although the surgeon should examine surgical procedures immediately after a TES-MEP alert, surgical intervention may not always be the best approach according to the results of this study.

Efficacy of Transcranial Motor Evoked Potential Monitoring During Intra- and Extramedullary Spinal Cord Tumor Surgery: A Prospective Multicenter Study of the Monitoring Committee of the Japanese Society for Spine Surgery and Related Research

STUDY DESIGN

Multicenter prospective study.

OBJECTIVES

Although intramedullary spinal cord tumor (IMSCT) and extramedullary SCT (EMSCT) surgeries carry high risk of intraoperative motor deficits (MDs), the benefits of transcranial motor evoked potential (TcMEP) monitoring are well-accepted; however, comparisons have not yet been conducted. This study aimed to clarify the efficacy of TcMEP monitoring during IMSCT and EMSCT resection surgeries.

METHODS

We prospectively reviewed TcMEP monitoring data of 81 consecutive IMSCT and 347 EMSCT patients. We compared the efficacy of interventions based on TcMEP alerts in the IMSCT and EMSCT groups. We defined our alert point as a TcMEP amplitude reduction of ≥70% from baseline.

RESULTS

In the IMSCT group, TcMEP monitoring revealed 20 true-positive (25%), 8 rescue (10%; rescue rate 29%), 10 false-positive, a false-negative, and 41 true-negative patients, resulting in a sensitivity of 95% and a specificity of 80%. In the EMSCT group, TcMEP monitoring revealed 20 true-positive (6%), 24 rescue (7%; rescue rate 55%), 29 false-positive, 2 false-negative, and 263 true-negative patients, resulting in a sensitivity of 91% and specificity of 90%. The most common TcMEP alert timing was during tumor resection (96% vs. 91%), and suspension surgeries with or without intravenous steroid administration were performed as intervention techniques.

CONCLUSIONS

Postoperative MD rates in IMSCT and EMSCT surgeries using TcMEP monitoring were 25% and 6%, and rescue rates were 29% and 55%. We believe that the usage of TcMEP monitoring and appropriate intervention techniques during SCT surgeries might have predicted and prevented the occurrence of intraoperative MDs.

Improvement of Lower Back Pain in Lumbar Spinal Stenosis After Decompression Surgery and Factors That Predict Residual Lower Back Pain

STUDY DESIGN

Retrospective observational study.

OBJECTIVES

There is no consensus to predict improvement of lower back pain (LBP) in lumbar spinal stenosis after decompression surgery. The aim of this study was to evaluate the improvement of LBP and analyze the preoperative predicting factors for residual LBP.

METHODS

We retrospectively reviewed 119 patients who underwent lumbar decompression surgery without fusion and had a minimum follow-up of 1 year. LBP was evaluated using the numerical rating scale (NRS), Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) LBP score, and Roland-Morris Disability Questionnaire (RMDQ). All patients were divided into LBP improved group (group I) and LBP residual group (group R) according to the NRS score. Radiographic images were examined preoperatively and at the final follow-up. We evaluated spinopelvic radiological parameters and analyzed the differences between group I and group R.

RESULTS

LBP was significantly improved after decompression surgery (LBP NRS, 5.7 vs 2.6, P < .001; JOABPEQ LBP score, 41.3 vs 79.6, P < .001; RMDQ, 10.3 vs 3.6, P < .001). Of 119 patients, 94 patients were allocated to group I and 25 was allocated to group R. There was significant difference in preoperative thoracolumbar kyphosis between group I and group R.

CONCLUSIONS

Most cases of LBP in lumbar spinal stenosis were improved after decompression surgery without fusion. Preoperative thoracolumbar kyphosis predicted residual LBP after decompression surgery.

Factors Influencing Patient Satisfaction After Decompression Surgery Without Fusion for Lumbar Spinal Stenosis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

Decompression without fusion is a standard surgical treatment for lumbar spinal stenosis (LSS) with reasonable surgical outcomes. Nevertheless, some studies have reported low patient satisfaction (PS) following decompression surgery. The cause of the discrepancy between reasonable clinical outcomes and PS is unknown; moreover, the factors associated with PS are expected to be complex, and little is known about them. This study aimed to identify satisfaction rate and to clarify the factors related to PS following decompression surgery in LSS patients.

METHODS

We retrospectively reviewed 126 patients who underwent lumbar decompression with a minimum follow-up of 1 year. Patients were divided into 2 groups based on the PS question. The Japanese Orthopaedic Association (JOA) scores, and the Numeric Rating Scale (NRS) scores of low back pain (LBP), leg pain, and leg numbness were compared between the 2 groups preoperatively and at the latest visit. To identify the prognostic factors for dissatisfaction, multiple logistic regression analysis was performed.

RESULTS

Overall satisfaction rate was 75%. The JOA recovery rate, NRS improvement, and Short Form-8 (SF-8) were significantly higher in the satisfied group. Postoperative NRS scores of LBP, leg pain, and leg numbness were significantly lower in the satisfied group. Multivariate logistic regression analysis showed that smoking and scoliosis were significant risk factors for dissatisfaction.

CONCLUSIONS

Overall satisfaction rate was 75% in patients with LSS undergoing decompression surgery. This study found that smoking status and scoliosis were associated with patient dissatisfaction following decompression in LSS patients.

Minimum clinically important difference of major patient-reported outcome measures in patients undergoing decompression surgery for lumbar spinal stenosis

OBJECTIVE

A minimum clinically important difference (MCID) has been increasingly well known in the current era of patient-centered care because it reflects a smallest change that is meaningful for patients following a clinical intervention. Previous studies suggested MCID values are disease and/or procedure dependent. No MCID values have been reported on the lumbar spinal stenosis (LSS) following decompression surgery despite LSS is the most common spinal disease and the main treatment is decompression surgery. Therefore, this study aimed to determine the MCID values as major outcome measures including the Numeric Rating Scale (NRS) of back pain, leg pain and numbness, Roland-Morris Disability Questionnaire (RMDQ), and Physical Component Summary (PCS) and Mental Component Summary (MCS) of Short Form 8 (SF-8) for patients with LSS undergoing decompression surgery.

PATIENTS AND METHODS

This is a retrospective cohort study using prospectively collected data from consecutive patients who underwent lumbar decompression without fusion for LSS at a single institution between May 2014 and March 2016. Inclusion criteria were 1) minimum 1-year follow-up 2) a complete set of preoperative and final follow-up questionnaires available, including the NRS, RMDQ, and SF-8. Revision surgery or non-degenerative etiology such as infection or tumor was excluded. MCIDs of each outcome measure were determined using two major approaches, distribution- and anchor-based methods. The distribution-based method uses the distributional characteristics of the sample. This method expresses the observed degree of variation to obtain a standardized metric such as the standard deviation or standard error of measurement. The anchor-based method uses an external criterion known as anchor to determine the factors that should be considered by patients for an important improvement. Anchor-based methods assess how much changes in the measurement instrument correspond with a minimal important change defined on the anchor. We used symptom severity, physical function, and satisfaction scores from Zurich Claudication Questionnaire as anchors for NRS and RMDQ, PCS, and MCS, respectively.

RESULTS

A total of 126 patients were included. From the anchor-based method, MCIDs were determined to be 2 points for back pain, 4 points for leg pain and numbness, 5 points for RMDQ, 5 points for PCS, and 2 points for MCS. From the distribution-based method, MCIDs were determined to be 2 points for back pain, leg pain and numbness, 3-4 points for RMDQ, 6 points for PCS, and 5 points for MCS.

CONCLUSION

We first identified the MCIDs of the NRS, RMDQ, and SF-8 specific to patients undergoing decompression surgery for LSS.

Risk factors for persistent numbness following decompression surgery for lumbar spinal stenosis

OBJECTIVE

Decompression surgery is a mainstay of surgical treatment for lumbar spinal stenosis (LSS). However, up to 30% of patients have low satisfaction due to residual symptoms. In the clinical setting, improvements in leg pain are more significant than those in leg numbness. Residual numbness could be related to the relatively low satisfaction rate. However, few studies have focused on numbness; thus, elucidating the risk factors and rate of residual numbness would benefit surgeons and patients. This study aimed to clarify the risk factors for and rate of residual numbness after decompression surgery.

PATIENTS AND METHODS

We retrospectively reviewed prospectively collected data from consecutive patients who underwent lumbar decompression without fusion for LSS at a single institution between January 2014 and March 2016. Patients were included if preoperative and final follow-up questionnaires and radiographs were available. A minimum one-year follow-up was required. We evaluated the Numeric Rating Scale (NRS) scores of low back pain, leg pain, and leg numbness preoperatively and at the final follow-up visit. Residual numbness was defined as a postoperative NRS ≥ 1, whereas persistent numbness was defined as a postoperative NRS ≥ 5. We compared the clinical data of patients with or without residual numbness to those of patients with or without persistent numbness. Multivariate logistic regression analysis was performed to identify risk factors for residual and persistent numbness.

RESULTS

A total of 116 patients (73 men, 43 women) were included. Of them, 60% had residual numbness with a mean follow-up period of 25 months. Only durotomy differed significantly between patients with and those without residual numbness. However, the significance did not persist after logistic regression analysis. A total of 16% had persistent numbness. Diabetes mellitus, intraoperative durotomy, and preoperative NRS of numbness were identified as risk factors. There were no differences in smoking status, presence of spondylolisthesis or scoliosis, or severity of stenosis.

CONCLUSIONS

We found three risk factors for persistent numbness following decompression surgery for LSS; diabetes mellitus and durotomy were modifiable, whereas preoperative numbness was not. Our findings would help surgeons minimize the incidence of persistent numbness by adequately controlling diabetes and avoiding durotomy during surgery. Providing information about the potential for residual numbness during the informed consent process is important to ensuring realistic patient expectations.

Gender Differences in Pre- and Postoperative Health-Related Quality of Life Measures in Patients Who Have Had Decompression Surgery for Lumbar Spinal Stenosis

Study Design

Retrospective chart audit.

Purpose

This study aimed to investigate the gender difference in pre- and postoperative health-related quality of life (HRQOL) in patients who have had decompression surgery for lumbar spinal stenosis (LSS).

Overview of Literature

Gender differences may contribute to variations in disease presentations and health outcomes. The influence of gender on pre- and postoperative HRQOL in spinal disorders remains unclear.

Methods

We reviewed 125 patients (79 men and 46 women) who had lumbar spinous process splitting laminectomy (LSPSL) for LSS. We assessed the following clinical information: Japanese Orthopedic Association (JOA) score; numerical rating scale (NRS) for low back pain (LBP), leg pain, and leg numbness; Zurich Claudication Questionnaire; JOA Back Pain Evaluation Questionnaire; Roland- Morris Disability Questionnaire (RMDQ); and Short Form 8 (SF-8) as HRQOL. We compared the HRQOLs of men and women pre- and postoperatively.

Results

Although the preoperative NRS results for LBP were significantly higher in women (p <0.05), there were no significant differences in clinical outcomes between men and women postoperatively. For HRQOL, the RMDQ scores were significantly worse in women preoperatively (p <0.05), but no significant differences were found postoperatively between men and women. Similarly, the SF-8 mental health score was also significantly lower in women preoperatively (p <0.05), but no significant differences were noted between the two groups postoperatively.

Conclusions

LSPSL greatly reduced LBP, leg pain, and leg numbness in both genders. There were limited differences in pain and several HRQOL questionnaire responses between men and women after surgery. We found that women had greater sensitivity to and/or lower tolerance for pain than men, which led to lower HRQOL mental health scores preoperatively.

Incidences and Risk Factors for Postoperative Non-Union after Posterior Lumbar Interbody Fusion with Closed-Box Titanium Spacers

Study Design

A retrospective, single-center clinical study with follow-up of more than 24 months.

Purpose

To evaluate the union rates and relevant risk factors for non-union after posterior lumbar interbody fusion (PLIF) using porous-coated closed-box titanium spacers.

Overview of Literature

Although the use of a closed-box interbody spacer for PLIF could avoid potential complications associated with the harvesting of autologous bone, few studies have reported detailed follow-up of fusion progression and risk factors for non-union in the early postoperative period.

Methods

PLIF using closed-box spacers without filling the autologous bone was performed in 78 (88 levels) consecutive patients. Surgical procedures included PLIF using traditional pedicle screw fixation (PLIF, n=37), PLIF using cortical bone trajectory screw fixation (CBT-PLIF, n=30), and transforaminal lumbar interbody fusion with traditional pedicle screw fixation (TLIF, n=11). Lateral dynamic radiography and computed tomography findings were investigated, and the relationship between the union status and variables that may be related to the risk of non-union was tested statistically.

Results

The overall bone union rates at 12 and 24 months were 68.0% and 88.5%, respectively. Incidences of bone cyst formation, subsidence, and retropulsion of spacers were 33.3%, 47.4%, and 14.1%, respectively. Union rates at 24 months were 94.6% in PLIF, 80.0% in CBT-PLIF, and 90.9% in TLIF. Multivariate logistic regression analyses showed that at 12 months postoperatively, the risk factor for non-union was age >75 years (p =0.02). In contrast, no significant risk factor was observed at 24 months.

Conclusions

These findings demonstrated the efficacy of interbody closed-box spacers for PLIF without the need to fill the spacer with autologous bone. However, the risk of non-union should be considered in elderly patients, especially intra-operatively and during the early postoperative stage.

The influence of preoperative mental health on clinical outcomes after laminectomy in patients with lumbar spinal stenosis

OBJECTIVE

The influence of preoperative mental health on health-related quality of life (HRQOL) in patients with lumbar spinal stenosis (LSS) remains unclear. This study aims to investigate the influence of preoperative mental health HRQOL after laminectomy in patients with LSS.

PATIENTS AND METHODS

We retrospectively reviewed 122 patients who had lumbar spinous process splitting laminectomy (LSPSL) for LSS. We assessed clinical information; Japanese Orthopedic Association (JOA) score; numerical rating scale (NRS) for low back pain, for leg pain, and for leg numbness; Zurich Claudication Questionnaire (ZCQ); JOA Back Pain Evaluation Questionnaire (JOABPEQ); Roland-Morris Disability Questionnaire (RMDQ); and Short Form 8 (SF-8) as patient reported outcomes. Patients were divided into two groups (Group L ≤ 36.2 points and Group NL > 36.2 points) based on the results of the preoperative mental health (MH) score in SF-8 to examine the influence of MH in LSS. We compared the HRQOL between the two groups postoperatively.

RESULTS

The JOA score, NRS, and ZCQ score significantly improved after surgery. HRQOL outcomes including JOABPEQ, RMDQ, and SF-8 showed that the LSPSL improved not only the physical but also the mental function in patients with LSS. All HRQOL outcomes in Group L exhibited significantly worse scores preoperatively; however, no significant differences between two groups were found postoperatively.

CONCLUSIONS

LSPSL greatly reduced low back pain, leg pain, and leg numbness. LSPSL resulted in a significant improvement based on HRQOL questionnaires even in patients with preoperative depressive mood. Not only the physical status but also the mental health may improve after LSPSL even in patients with LSS with a depressive mood preoperatively.

Impact of decompression surgery without fusion for lumbar spinal stenosis on sagittal spinopelvic alignment: minimum 2-year follow-up

OBJECTIVE

The importance of global sagittal alignment is well known. Patients with lumbar spinal stenosis (LSS) generally tend to bend forward to relieve their neurological symptoms, i.e., they have a positive sagittal vertical axis (SVA). We hypothesized that the positive SVA associated with LSS is symptom related and should improve after surgery. However, little is known about the changes in sagittal alignment in LSS patients after decompression surgery. In this study the authors aimed to evaluate midterm radiographical changes in sagittal spinopelvic alignment after decompression surgery for LSS and to determine the factors influencing the improvement in sagittal spinopelvic alignment.

METHODS

The authors retrospectively reviewed 89 patients who underwent lumbar decompression without fusion between January 2014 and September 2015 with a minimum follow-up of 2 years. Standing whole-spine radiographs at the preoperative stage and at the final follow-up were examined. We analyzed SVA, lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), thoracolumbar kyphosis (TLK), and thoracic kyphosis (TK).

RESULTS

LL and TK were significantly increased postoperatively. SVA and PI minus LL (PI-LL) were significantly decreased. There were no significant differences between the preoperative and postoperative PT, PI, SS, or TLK. Twenty-nine patients had preoperative sagittal malalignment with SVA > 50 mm. Thirteen of the 29 patients improved to SVA < 50 mm after decompression surgery. Lower ASA grade, preoperative higher LL, and lower PI-LL were related to patient improvement. A receiver operating characteristic curve for the preoperative PI-LL had an area under the curve value of 0.821, indicating moderate accuracy (p = 0.003). A cutoff value for preoperative PI-LL of 19.2° showed a sensitivity of 93.5% and a specificity of 71.4%.

CONCLUSIONS

Lumbar decompression can lead to a reactive improvement in the lumbar and global sagittal alignment. However, some of the sagittal malalignment in LSS was irreversible. Preoperative PI-LL was a useful predictor to distinguish reversible from irreversible sagittal malalignment.

Impact of sagittal spinopelvic alignment on clinical outcomes and health-related quality of life after decompression surgery without fusion for lumbar spinal stenosis

OBJECTIVE

Patients with lumbar spinal stenosis (LSS) tend to bend forward to relieve neurological symptoms. They therefore have a positive sagittal vertical axis (SVA). The importance of the SVA value is well known in the field of adult spinal deformity; however, little is known about its impact on LSS. The authors sought to investigate the impact of sagittal spinopelvic alignment on clinical outcome and health-related quality of life (HRQOL) after decompression surgery for LSS.

METHODS

The authors retrospectively reviewed 83 patients who underwent lumbar decompression without fusion between January 2014 and September 2015 with a minimum follow-up of 2 years. Standing whole-spine radiographs were examined preoperatively and at final follow-up. Based on the SVA, patients were allocated to a sagittal balance group (group B; SVA < 50 mm) or a sagittal imbalance group (group I; SVA ≥ 50 mm). The authors compared the groups using Japanese Orthopaedic Association (JOA), Zurich Claudication Questionnaire (ZCQ), Roland-Morris Disability Questionnaire (RMDQ), and the 8-item Short Form Health Survey (SF-8) scores.

RESULTS

Preoperative groups B (group pre-B) and I (group pre-I) included 58 and 25 patients, respectively. Preoperative sagittal malalignment had negative effects on the JOA score recovery rate, postoperative ZCQ physical function domain score, and numeric rating scale (NRS) score of postoperative low-back pain (LBP), but no significant effects were observed for RMDQ and SF-8 domain scores. Postoperatively, groups B (group post-B) and I (group post-I) included 60 and 23 patients, respectively. Group post-I had a significantly worse JOA score recovery rate, postoperative symptom severity domain score in the ZCQ, and NRS score for postoperative LBP. Similarly, the postoperative RMDQ score and the Physical Component Summary score of the SF-8 were significantly worse in group post-I.

CONCLUSIONS

Positive SVA had significantly negative effects on clinical outcome and HRQOL in LSS patients after lumbar decompression surgery.

A New Treatment for Dialysis-Related Amyloidosis with β 2-Microglobulin Adsorbent Column

Dialysis-related amyloidosis (DRA) is characterized by the presence of β 2-microglobulin (β 2-m) in the plasma. In order to eliminate β 2-m from the circulating blood, the β 2-m selective adsorbent for direct hemoperfusion (DHP) was developed. A DHP column (BM-01), containing 350 ml of the adsorbent, was subjected to clinical trials. The column was connected with a PAN (AN69) membrane dialyzer in series and used 3 times a week for 1 week (11 patients), 4 weeks (5 patients), 6 months (1 patient) and 12 months (2 patients). The percent reduction (%) of β 2-m was for 16 patients (for 1 or 4 weeks), more than 65, and for 3 patients (for more than 6 months), 76.5 ± 4.9, 73.5 ± 5.7, 72.2 ± 6.2. At the end of each session, β 2-m plasma levels were found to be below 10 mg/L, with 3.4 mg/L being the lowest. The total amounts of β 2-m removed were 172.5 ± 22.3, 257.0 ± 75.6, 157.6 ± 32.2 and 429.8 mg/session at max. Two out of these three patients had a favorable effect on joint symptoms and ocular fundus. It can be concluded that this selective adsorption therapy may delay the progression of DRA, and is worth considering for wide application.

Risk factor analysis of kyphotic malalignment after cervical intramedullary tumor resection in adults

OBJECTIVE

A number of studies have reported that surgery for cervical intramedullary tumors via the posterior approach can result in postoperative sagittal malalignment of the cervical spine; however, the risk factors remain unclear. The purpose of this study was to investigate the changes in cervical spinal alignment after surgery for cervical intramedullary tumors in adults and to elucidate the risk factors for cervical spinal sagittal misalignment.

METHODS

Data for the period from April 2001 to December 2011 for all adults who had undergone surgery for cervical intramedullary spinal cord tumors at a single institution were retrospectively analyzed to determine the postoperative changes in cervical spine alignment. Patients younger than 20 years of age and those who required postoperative radiotherapy were excluded from the study. Patients were divided into 2 groups according to tumor location: upper tumor (U) group, in which the central region of the tumor was above the C-5 level; and lower tumor (L) group, in which the central region of the tumor was at or below the C-5 level. Changes in alignment of the cervical spine were measured on plain lateral radiographs. Data on atrophy of the deep extensor muscles (DEMs), tumor location, detachment of the DEMs from the C-2 spinous process, the C2–7 angle before surgery, patient age at surgery, tumor histology, patient sex, tumor size, and number of laminae affected were reviewed for each patient, and the correlation of each of these factors with cervical spinal malalignment was evaluated using statistical analysis.

RESULTS

The 54 adults eligible for analysis had a mean age of 49.1 years. Ependymoma was the most common cervical intramedullary tumor (63.0%) in this series. In the tumor location U group, the kyphotic angle of the C2–7 spinal segments increased after surgery (−5.8° ± 2.8°). In contrast, in the L group, the C2–7 lordotic angle increased after surgery (6.4° ± 2.6°). In the univariate analysis, atrophy of the DEMs, detachment of the DEMs from the C-2 spinous process, and an upper cervical location of the tumor were identified as factors significantly correlated with the development of cervical spinal kyphosis after surgery. Multiple linear regression analysis revealed the following as risk factors for kyphotic change of the cervical spine after surgery: 1) atrophy of the DEMs after surgery (β = −0.54, p < 0.01), and 2) detachment of the DEMs from the C-2 spinous process (β = −0.37, p < 0.01).

CONCLUSIONS

Atrophy of the DEMs after surgery and detachment of the DEMs from the C-2 spinous process are directly related to the risk of cervical spinal kyphosis after surgery for cervical intramedullary tumors in adults. Therefore, preservation of the DEMs, especially those attached to the C-2 spinous process, is important for the prevention of kyphotic malalignment of the cervical spine after surgery for intramedullary tumors.

Enhanced Functional Recovery from Spinal Cord Injury in Aged Mice after Stem Cell Transplantation through HGF Induction

The number of elderly patients with spinal cord injury (SCI) is increasing worldwide, representing a serious burden for both the affected patients and the community. Previous studies have demonstrated that neural stem cell (NSC) transplantation is an effective treatment for SCI in young animals. Here we show that NSC transplantation is as effective in aged mice as it is in young mice, even though aged mice exhibit more severe neurological deficits after SCI. NSCs grafted into aged mice exhibited better survival than those grafted into young mice. Furthermore, we show that the neurotrophic factor HGF plays a key role in the enhanced functional recovery after NSC transplantation observed in aged mice with SCI. The unexpected results of the present study suggest that NSC transplantation is a potential therapeutic modality for SCI, even in elderly patients.

Denervation-Associated Change in the Palatinus and Levator Veli Palatini Muscles of Dogs with Elongated Soft Palate

Muscle lesions and decreased numbers of peripheral nerve branches have been reported in the soft palates of dogs presenting with brachycephalic airway obstruction syndrome (BAOS). Myosin adenosine triphosphatase staining was employed to investigate whether muscle lesions in the elongated soft palate (ESP) of dogs with BAOS reflect the presence of denervation. Soft palates were collected from nine brachycephalic dogs during surgical intervention for BAOS and from five healthy beagle dogs as controls. In the control soft palates, myofibres with relatively uniform diameters and a random mosaic pattern of type I and II myofibres were observed in the palatinus muscle (PM), while almost all of the myofibres in the levator veli palatini muscle (LVPM) were of type II. In the ESPs, small group atrophy, large group atrophy and angular-shaped atrophy were observed in myofibres of the PM and rarely in the LVPM. Fibre type grouping and an increase in type IIC myofibres were found only in the PM. Morphometric analysis of ESPs revealed a significant increase in the number of type I and II myofibres in the PM showing atrophy or hypertrophy compared with controls. A significant increase in atrophic type II myofibres was found in the LVPM of affected dogs. Myopathy consistent with denervation was observed in the PM, but rarely in the LVPM, of ESP specimens. The results suggest that the myopathy seen in dogs with ESP may partly reflect atrophy of myofibres resulting from damage to peripheral nerve branches, with subsequent reinnervation of myofibres.

Sustained Effect of Hyaluronic Acid in Subcutaneous Administration to the Cochlear Spiral Ganglion

The spatiotemporal distribution of drugs in the inner ear cannot be precisely evaluated because of its small area and complex structure. In the present study, we used hyaluronic acid (HA)-dispersed luciferin to image transgenic mice and to determine the effect of HA on controlled drug delivery to the cochlea. GFAP-luc mice, which express luciferase in cochlear spiral ganglion cells, were subcutaneously administered HA-luciferin (HA-sc) or luciferin dissolved in saline (NS-sc) or intraperitoneally administered luciferin dissolved in saline (NS-ip). The bioluminescence of luciferin was monitored in vivo in real time. The peak time and half-life of fluorescence emission were significantly increased in HA-sc-treated mice compared with those in NS-sc- and NS-ip-treated mice; however, significant differences were not observed in peak photon counts. We detected differences in the pharmacokinetics of luciferin in the inner ear, including its sustained release, in the presence of HA. The results indicate the clinical potential of using HA for controlled drug delivery to the cochlea.

Transplantation of Neural Stem/Progenitor Cells at Different Locations in Mice with Spinal Cord Injury

Transplantation of neural stem/progenitor cells (NS/PCs) promotes functional recovery after spinal cord injury (SCI); however, few studies have examined the optimal site of NS/PC transplantation in the spinal cord. The purpose of this study was to determine the optimal transplantation site of NS/PCs for the treatment of SCI. Wild-type mice were generated with contusive SCI at the T10 level, and NS/PCs were derived from fetal transgenic mice. These NS/PCs ubiquitously expressed ffLuc-cp156 protein (Venus and luciferase fusion protein) and so could be detected by in vivo bioluminescence imaging 9 days postinjury. NS/PCs (low: 250,000 cells per mouse; high: 1 million cells per mouse) were grafted into the spinal cord at the lesion epicenter (E) or at rostral and caudal (RC) sites. Phosphate-buffered saline was injected into E as a control. Motor functional recovery was better in each of the transplantation groups (E-Low, E-High, RC-Low, and RC-High) than in the control group. The photon counts of the grafted NS/PCs were similar in each of the four transplantation groups, suggesting that the survival of NS/PCs was fairly uniform when more than a certain threshold number of cells were transplanted. Quantitative RT-PCR analyses demonstrated that brain-derived neurotropic factor expression was higher in the RC segment than in the E segment, and this may underlie why NS/PCs more readily differentiated into neurons than into astrocytes in the RC group. The location of the transplantation site did not affect the area of spared fibers, angiogenesis, or the expression of any other mediators. These findings indicated that the microenvironments of the E and RC sites are able to support NS/PCs transplanted during the subacute phase of SCI similarly. Optimally, a certain threshold number of NS/PCs should be grafted into the E segment to avoid damaging sites adjacent to the lesion during the injection procedure.

Focal transplantation of human iPSC-derived glial-rich neural progenitors improves lifespan of ALS mice

Transplantation of glial-rich neural progenitors has been demonstrated to attenuate motor neuron degeneration and disease progression in rodent models of mutant superoxide dismutase 1 (SOD1)-mediated amyotrophic lateral sclerosis (ALS). However, translation of these results into a clinical setting requires a renewable human cell source. Here, we derived glial-rich neural progenitors from human iPSCs and transplanted them into the lumbar spinal cord of ALS mouse models. The transplanted cells differentiated into astrocytes, and the treated mouse group showed prolonged lifespan. Our data suggest a potential therapeutic mechanism via activation of AKT signal. The results demonstrated the efficacy of cell therapy for ALS by the use of human iPSCs as cell source.

Novel method for analyzing locomotor ability after spinal cord injury in rats: technical note

In the research for the treatment of spinal cord injury (SCI), the evaluation of motor function in model rats must be as objective, noninvasive, and ethical as possible. The maximum speed and acceleration of a mouse measured using a SCANET system were previously reported to vary significantly according to severity of SCI. In the present study, the motor performance of SCI model rats was examined with SCANET and assessed for Basso-Beattie-Bresnahan (BBB) score to determine the usefulness of the SCANET system in evaluating functional recovery after SCI. Maximum speed and acceleration within the measurement period correlated significantly with BBB scores. Furthermore, among several phased kinematic factors used in BBB scores, the capability of “plantar stepping” was associated with a drastic increase in maximum speed and acceleration after SCI. Therefore, evaluation of maximum speed and acceleration using a SCANET system is a useful method for rat models of SCI and can complement open field scoring scales.

Abstract 216: HMGB1 regulates homing capacity of human mesenchymal stromal cells into colon cancer

Recently a growing corpus of studies has highlighted the important aspect of Mesenchymal Stem Cell (MSC) therapy: systemically administered MSCs home to sites of cancer. In this study, we focused on a homing mechanism of human MSCs into cancer. First, we examined if cultured medium from cancer cell lines could modulate migration of MSCs, the secretion level of HMGB1 from six different colon cancer cell lines affected the migration capacity of MSCs. In addition, recombinant HMGB1 could increase the migration capacity in dose dependent manner. Finally, we applied MSCs intracutaneously into mice bearing colon cancer using a cell line which secreted high level of HMGB1. The in vivo bioluminescence live-image showed that MSCs surrounded the tumors within 48hours after their injection, additionally the immunohistochemistry revealed the existence of MSCs in the tumors. These findings are critical in understanding the role of MSCs in solid cancer, further they might facilitate therapeutic application of MSCs in the treatment of cancer.

Citation Format: Go Hoshino, Hiroshi Yagi, Hirotoshi Hasegawa, Yoshiyuki Ishii, Takashi Endo, Koji Okabayashi, Akimasa Yasuda, Masaya Nakamura, Hideyuki Okano, Yumi Matsuzaki, Yuko Kitagawa. HMGB1 regulates homing capacity of human mesenchymal stromal cells into colon cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 216. doi:10.1158/1538-7445.AM2013-216

Time-dependent changes in the microenvironment of injured spinal cord affects the therapeutic potential of neural stem cell transplantation for spinal cord injury

Background

The transplantation of neural stem/progenitor cells (NS/PCs) at the sub-acute phase of spinal cord injury, but not at the chronic phase, can promote functional recovery. However, the reasons for this difference and whether it involves the survival and/or fate of grafted cells under these two conditions remain unclear. To address this question, NS/PC transplantation was performed after contusive spinal cord injury in adult mice at the sub-acute and chronic phases.

Results

Quantitative analyses using bio-imaging, which can noninvasively detect surviving grafted cells in living animals, revealed no significant difference in the survival rate of grafted cells between the sub-acute and chronic transplantation groups. Additionally, immunohistology revealed no significant difference in the differentiation phenotypes of grafted cells between the two groups. Microarray analysis revealed no significant differences in the expression of genes encoding inflammatory cytokines or growth factors, which affect the survival and/or fate of grafted cells, in the injured spinal cord between the sub-acute and chronic phases. By contrast, the distribution of chronically grafted NS/PCs was restricted compared to NS/PCs grafted at the sub-acute phase because a more prominent glial scar located around the lesion epicenter enclosed the grafted cells. Furthermore, microarray and histological analysis revealed that the infiltration of macrophages, especially M2 macrophages, which have anti-inflammatory role, was significantly higher at the sub-acute phase than the chronic phase. Ultimately, NS/PCs that were transplanted in the sub-acute phase, but not the chronic phase, promoted functional recovery compared with the vehicle control group.

Conclusions

The extent of glial scar formation and the characteristics of inflammation is the most remarkable difference in the injured spinal cord microenvironment between the sub-acute and chronic phases. To achieve functional recovery by NS/PC transplantation in cases at the chronic phase, modification of the microenvironment of the injured spinal cord focusing on glial scar formation and inflammatory phenotype should be considered.

MRI characterization of paranodal junction failure and related spinal cord changes in mice

The paranodal junction is a specialized axon-glia contact zone that is important for normal neuronal activity and behavioral locomotor function in the central nervous system (CNS). Histological examination has been the only method for detecting pathological paranodal junction conditions. Recently, diffusion tensor MRI (DTI) has been used to detect microstructural changes in various CNS diseases. This study was conducted to determine whether MRI and DTI could detect structural changes in the paranodal junctions of the spinal cord in cerebroside sulfotransferase knock-out (CST-KO) mice. Here, we showed that high-resolution MRI and DTI characteristics can reflect paranodal junction failure in CST-KO mice. We found significantly lower T1 times and significantly higher T2 times in the spinal cord MRIs of CST-KO mice as compared to wild-type (WT) mice. Spinal cord DTI showed significantly lower axial diffusivity and significantly higher radial diffusivity in CST-KO mice as compared to WT mice. In contrast, the histological differences in the paranodal junctions of WT and CST-KO mice were so subtle that electron microscopy or immunohistological analyses were necessary to detect them. We also measured gait disturbance in the CST-KO mice, and determined the conduction latency by electrophysiology. These findings demonstrate the potential of using MRI and DTI to evaluate white matter disorders that involve paranodal junction failure.

Pre-evaluated safe human iPSC-derived neural stem cells promote functional recovery after spinal cord injury in common marmoset without tumorigenicity

Murine and human iPSC-NS/PCs (induced pluripotent stem cell-derived neural stem/progenitor cells) promote functional recovery following transplantation into the injured spinal cord in rodents. However, for clinical applicability, it is critical to obtain proof of the concept regarding the efficacy of grafted human iPSC-NS/PCs (hiPSC-NS/PCs) for the repair of spinal cord injury (SCI) in a non-human primate model. This study used a pre-evaluated “safe” hiPSC-NS/PC clone and an adult common marmoset (Callithrix jacchus) model of contusive SCI. SCI was induced at the fifth cervical level (C5), followed by transplantation of hiPSC-NS/PCs at 9 days after injury. Behavioral analyses were performed from the time of the initial injury until 12 weeks after SCI. Grafted hiPSC-NS/PCs survived and differentiated into all three neural lineages. Furthermore, transplantation of hiPSC-NS/PCs enhanced axonal sparing/regrowth and angiogenesis, and prevented the demyelination after SCI compared with that in vehicle control animals. Notably, no tumor formation occurred for at least 12 weeks after transplantation. Quantitative RT-PCR showed that mRNA expression levels of human neurotrophic factors were significantly higher in cultured hiPSC-NS/PCs than in human dermal fibroblasts (hDFs). Finally, behavioral tests showed that hiPSC-NS/PCs promoted functional recovery after SCI in the common marmoset. Taken together, these results indicate that pre-evaluated safe hiPSC-NS/PCs are a potential source of cells for the treatment of SCI in the clinic.

Novel in vivo imaging analysis of an inner ear drug delivery system in mice: comparison of inner ear drug concentrations over time after transtympanic and systemic injections

Objective

Systemic steroid injections are used to treat idiopathic sudden-onset sensorineural hearing loss (ISSHL) and some inner ear disorders. Recent studies show that transtympanic (TT) steroid injections are effective for treating ISSHL. As in vivo monitoring of drug delivery dynamics for inner ear is lacking, its time course and dispersion of drugs is unknown. Here, we used a new in vivo imaging system to monitor drug delivery in live mice and to compare drug concentrations over time after TT and systemic injections.

Methods

Luciferin delivered into the inner ears of GFAP-Luc transgenic mice reacted with luciferase in GFAP-expressing cells in the cochlear spiral ganglion, resulting in photon bioluminescence. We used the Xenogen IVIS® imaging system to measure how long photons continued to be emitted in the inner ear after TT or systemic injections of luciferin, and then compared the associated drug dynamics.

Results

The response to TT and IP injections differed significantly. Photons were detected five minutes after TT injection, peaking at ∼20 minutes. By contrast, photons were first detected 30 minutes after i.p. injection. TT and i.p. drug delivery time differed considerably. With TT injections, photons were detected earlier than with IP injections. Photon bioluminescence also disappeared sooner. Delivery time varied with TT injections.

Conclusions

We speculate that the drug might enter the Eustachian tube from the middle ear. We conclude that inner-ear drug concentration can be maintained longer if the two injection routes are combined. As the size of luciferin differs from that of therapeutics like dexamethasone, combining drugs with luciferin may advance our understanding of in vivo drug delivery dynamics in the inner ear.

[Posterior mediastinal hemangioma with extramedullary haematopoieisis]

We report a very rare coexistence of posterior mediastinal hemangioma with extramedullary haematopoieisis. A 69-year-old woman was detected to have an abnormal mass on the chest radiograph during a routine medical examination. No disorders were found by hematologic exams before and after surgery. Chest computed tomography (CT) revealed a well circumscribed posterior mediastinal tumor measured 32×11 mm in diameter, located on paravertebral space. The most likely diagnosis was a benign neurogenic tumor and we were planning to remove this tumor by video-assisted thoracic surgery (VATS) via a right transthoracic approach. Thoracoscopic finding revealed that this tumor was brownish and soft, such as hemangioma. Initially, incisional biopsy was done to obtain definitive diagnosis. Since intraoperative microscopic examination of the biopsy specimen revealed extramedullary haematopoieisis, we obtained another larger samples and finished the operation. Interestingly, the postoperative final histological diagnosis was mediastinal hemangioma with extramedullary haematopoieis.

Bioluminescent system for dynamic imaging of cell and animal behavior

The current utility of bioluminescence imaging is constrained by a low photon yield that limits temporal sensitivity. Here, we describe an imaging method that uses a chemiluminescent/fluorescent protein, ffLuc-cp156, which consists of a yellow variant of Aequorea GFP and firefly luciferase. We report an improvement in photon yield by over three orders of magnitude over current bioluminescent systems. We imaged cellular movement at high resolution including neuronal growth cones and microglial cell protrusions. Transgenic ffLuc-cp156 mice enabled video-rate bioluminescence imaging of freely moving animals, which may provide a reliable assay for drug distribution in behaving animals for pre-clinical studies.

Beneficial compaction of spinal cord lesion by migrating astrocytes through glycogen synthase kinase-3 inhibition

The migratory response of astrocytes is essential for restricting inflammation and preserving tissue function after spinal cord injury (SCI), but the mechanisms involved are poorly understood. Here, we observed stimulation of in vitro astrocyte migration by the new potent glycogen synthase kinase-3 (GSK-3) inhibitor Ro3303544 and investigated the effect of Ro3303544 administration for 5 days following SCI in mice. This treatment resulted in accelerated migration of reactive astrocytes to sequester inflammatory cells that spared myelinated fibres and significantly promoted functional recovery. Moreover, the decreased extent of chondroitin sulphate proteoglycans and collagen IV demonstrated that scarring was reduced in Ro3303544-treated mice. A variety of in vitro and in vivo experiments further suggested that GSK-3 inhibition stimulated astrocyte migration by decreasing adhesive activity via reduced surface expression of β1-integrin. Our results reveal a novel benefit of GSK-3 inhibition for SCI and suggest that the stimulation of astrocyte migration is a feasible therapeutic strategy for traumatic injury in the central nervous system.

Schwann-spheres derived from injured peripheral nerves in adult mice--their in vitro characterization and therapeutic potential

Multipotent somatic stem cells have been identified in various adult tissues. However, the stem/progenitor cells of the peripheral nerves have been isolated only from fetal tissues. Here, we isolated Schwann-cell precursors/immature Schwann cells from the injured peripheral nerves of adult mice using a floating culture technique that we call “Schwann-spheres." The Schwann-spheres were derived from de-differentiated mature Schwann cells harvested 24 hours to 6 weeks after peripheral nerve injury. They had extensive self-renewal and differentiation capabilities. They strongly expressed the immature-Schwann-cell marker p75, and differentiated only into the Schwann-cell lineage. The spheres showed enhanced myelin formation and neurite growth compared to mature Schwann cells in vitro. Mature Schwann cells have been considered a promising candidate for cell-transplantation therapies to repair the damaged nervous system, whereas these “Schwann-spheres" would provide a more potential autologous cell source for such transplantation.

Transmission of cytomegalovirus via breast milk in extremely premature infants

OBJECTIVE

We prospectively evaluated the rate of postnatal cytomegalovirus (CMV) transmission through breast milk in extremely premature infants to address the impact of CMV infection on preterm infants during lactation.

STUDY DESIGN

A total of 25 mothers and 27 infants (two sets of twins) with birth weights <1000 g and/or gestational ages <28 weeks were enrolled in the study. They were mostly fed frozen-thawed breast milk. Breast milk, serum and urine samples were collected every 2 weeks and screened for CMV infection using the real-time polymerase chain reaction.

RESULT

All of the 21 CMV-seropositive mothers had detectable CMV DNA in their breast milk, with a peak at 4 to 6 weeks postpartum. CMV infection was confirmed in only one infant (4.3%) who displayed almost no clinical symptoms.

CONCLUSION

At our institutes, we mainly use frozen-thawed breast milk. We found low CMV transmission rates even in extremely premature infants, and the CMV-positive infant did not develop serious symptoms.