Radiation Exposure During Lumbar Interbody Fusion Surgery Can Be Reduced by Using a Three-Dimensional Patient-Specific Template Guide.

BACKGROUND: The use of posterior lumber interbody fusion (PLIF) using cortical bone trajectory (CBT) with a patient-specific 3D template guide is increasingly widespread. To our knowledge, no studies have extensively evaluated the reduction of radiation exposure when using patient-specific drill template guides. The purpose of this study is to compare the intra-operative radiation dose and surgeon's exposure to radiation in CBT-PLIF when using a patient-specific drill guide with that in traditional minimally invasive (MIS)-PLIF. METHODS: In this observational study, we retrospectively compared data from five patients who were treated with single-level CBT-PLIF using a patient-specific drill guide (G group) and five patients who were treated with single-level traditional MIS-PLIF (M group). We compared the surgical time, surgeon's exposure to radiation, and intra-operative radiation time and dose between the two groups of patients. RESULTS: The mean age of the patients was 67.0 years in the M group and 74.2 years in the G group. The average surgical time was 242.8 min in the M group and 189.6 min in the G group (p = 0.020). The surgeon's exposure to radiation was 373.7 µSv in the M group and 81.75 µSv in the G group at chest level outside the protector (p = 0.00092); 42.0 µSv (M group) and 3.6 µSv (G group) at chest level inside the protector (p = 0.0000062); and 4.33 µSv (M group) and 1.20 µSv (G group) at the buttocks of the surgeon (p = 0.0013). Radiation time was 269.8 s (M group) and 56.6 s (G group) (p = 0.0097), and radiation dose was 153.7 mGy (M group) and 30.42 mGy (G group) (p = 0.00057). CONCLUSION: The patient-specific drill template guide is an invaluable tool that facilitates the safe insertion of CBT screws with a low radiation dose from the outset.

Quantitative evaluation of the lumbar ligamentum flavum using MRI T2-mapping: Efficacy of its clinical application in patients with lumbar spinal stenosis.

OBEJECTIVE: To perform a magnetic resonance imaging T2-mapping of the ligamentum flavum in healthy individuals and patients with lumbar spinal stenosis scheduled for surgery and compare the T2 relaxation times. SUBJECTS AND METHODS: The T2 relaxation time of the ligamentum flavum was compared among 3 groups, healthy young individuals (H group (age< 50)), healthy middle-aged and older individuals (H group (age≥50)), and patients with lumbar spinal stenosis (L group). Additionally, the thickness of the ligament was measured in the axial image plane, and the occupied area ratio of each fiber was measured by staining the surgically obtained ligament, and each was correlated with the T2 relaxation time. We also evaluated the adhesion of the ligamentum flavum with the dura mater during the surgery. RESULTS: The T2 relaxation times were significantly prolonged in H group (age ≥50) and L group (P < 0.001) compared to H group (age<50). The relationship between collagen fiber and T2 relaxation times was significantly positive (r = 0.720, P < 0.001). Moreover, the relaxation times were significantly prolonged in those with adhesion of the ligamentum flavum with the dura mater (P < 0.05). The cut-off for the relaxation time was 50 ms (sensitivity: 62.50%, false positive rate: 10.8%). CONCLUSION: Healthy middle-aged and older individuals and patients with lumbar spinal stenosis and adhesion of the ligamentum flavum with the dura mater have prolonged T2 relaxation times. Hence, the adhesion between the ligamentum flavum and dura mater should be considered in cases with a relaxation time ≥50 ms.

Objective Assessment of Sleep Disorders in Patients with Lumbar Spinal Stenosis Using Wearable Trackers.

Introduction: Low-back pain causes sleep disorders, which impairs the quality of life (QOL) of patients. Sleep disorders are associated with lumbar spinal stenosis (LSS); however, the postoperative effects of LSS surgery on sleep disorders are unknown. This study aimed to assess sleep disorders in patients with LSS using wearable activity trackers and determine whether surgery improves sleep quality. Methods: A total of 39 patients scheduled for LSS surgery (mean age 71.1±8.7 years; 22 men and 17 women) were studied. Sleep disorders in the participants were objectively evaluated using a wearable Motionlogger Micro system. Sleep efficiency (SEf), mean active count (MAC), and wake after sleep onset (WASO) were measured before and 6 months following surgery. Furthermore, the patient-based outcomes of pain and QOL-related scores were measured and compared with those of healthy participants. The group with improved SEf following surgery was designated as "nonpoor sleepers," whereas the group that did not exhibit improvements was designated as "poor sleepers." The two groups were compared based on patient factors, patient-based questionnaires, and sleep disorder measurements. Results: The SEf and WASO were significantly worse in patients with LSS compared with healthy participants (P<0.05). Furthermore, the SEf in patients with LSS was associated with the Oswestry Disability Index scores. No improvement was observed in the SEf, MAC, and WASO before and after surgery. Evaluation of each case revealed 21 and 12 cases of nonpoor and poor sleepers, respectively. Preoperative low-back pain was significantly associated with improvement in postoperative sleep quality. Conclusions: Sleep disorders in patients with LSS were evaluated, and improvement in sleep disorders following surgery was associated with the intensity of preoperative low-back pain. Sleep disorders are associated with QOL disorders, suggesting that focusing on the treatment of sleep disorders is important in the management of patients with LSS.

Novel within ring fixation using iliac screws and an iliosacral screw locking system technique for fragility fracture of the pelvis.

Background: Surgical indications for fragility fracture of the pelvis (FFP) have been reconsidered recently, and the indications to perform surgery have increased. However, the optimal surgical method to obtain sufficiently strong fixation in elderly patients with minimal invasiveness is not yet clear. In this report, we present the case of a patient with FFP who was treated with a novel posterior within ring fixation technique using a combination of iliac screws and an implant that locks the original iliosacral (IS) screw in the sacrum. Case Description: A 90-year-old man was diagnosed with FFP (Rommens classification: Type IIc) and hospitalized for conservative treatment. However, 6 weeks after the injury, pain reappeared in his right buttock and computed tomography showed additional fractures of the right subpubic branch and right sacrum (Rommens classification: Type IVb). The fracture was considered to have progressed from being stable to unstable, and surgical treatment was planned. To obtain strong fixation with minimal invasion, we performed posterior fixation using E.Spine Tanit (Euros, France) compact posterior thoracolumbar instrumentation, an implant that combines an IS screw with a sacral anchoring system. The patient started walking unaided 2 weeks after the surgery, suggesting a good outcome of this surgical approach to FFP. Conclusion: We performed posterior fixation surgery for a patient with an unstable FFP that recurred and progressed after conservative treatment. We have achieved good results using a minimally invasive, strong, and within ring fixation technique.

Penetrating Endplate Screw Fixation for Thoracolumbar Pathological Fracture of Diffuse Idiopathic Skeletal Hyperostosis.

With the advancement of cancer treatment and minimally invasive surgery, the indications for surgery for metastatic spinal tumors are expanding. Diffuse idiopathic skeletal hyperostosis (DISH) is a noninflammatory skeletal disease characterized by calcification and ossification of ligaments and entheses. In Japan, the prevalence of DISH is increasing with its superaging society. The purpose of this article is to report a case of applying a novel screw technique for pathological fracture in a patient with DISH and spinal metastasis. An 80-year-old man with spinal metastasis presented with acute onset of severe back pain, and investigations revealed a fracture of a metastatic lesion in T10-T12 in the range of DISH. We performed posterior fixation with a percutaneous pedicle screw system using a penetrating endplate technique. The patient's back pain improved, and he was able to mobilize with minimal assistance and survived for 8 months with a good quality of life. Spinal fracture accompanied by DISH sometimes occurs with severe instability because of injury across 3-column injury and its long lever arm. Spinal instability neoplastic score indicates instability of pathological fractures of spinal metastases but needs to be evaluated carefully when DISH is present. The prevalence of DISH is increasing in the elderly, and penetrating endplate screws can be an effective option in posterior fusion surgery for patients with DISH and spinal metastases.

Efficacy and Safety of Condoliase Disc Administration as a New Treatment for Lumbar Disc Herniation.

INTRODUCTION: Condoliase is a newly approved drug that improves symptoms associated with lumbar disk herniation (LDH) by intradiscal administration. This study aimed to evaluate the mid-term outcomes of condoliase injection, examine the adverse events, including cases that required surgery after condoliase administration, and verify cases in which condoliase could be effective. METHODS: We enrolled patients with LDH who were treated conservatively for at least six weeks and received condoliase. We assessed the visual analog scale (VAS) score, Japanese Orthopaedic Association Back Pain Evaluation Questionnaire, Oswestry Disability Index, disk height, and disk degeneration for up to 6 months, and we examined the complications. Furthermore, a 50% or more improvement in leg pain VAS score was considered effective. Factors related to symptom improvement were investigated by determining whether lower limb pain improved in six months. RESULTS: In total, 84 patients were recruited (52 men, 32 women; mean age, 44.2 ± 17.1 [16-86 years]). The duration of illness was 6.7 ± 6.8 (1.5-30) months. All patient-based outcomes significantly improved at 4 weeks after the administration compared with pretreatment. The intervertebral disc height decreased significantly at four weeks after condoliase administration compared with that before administration. Progression of intervertebral disc degeneration occurred in 50% of the patients. Eleven patients underwent herniotomy due to poor treatment effects. Moreover, treatment in 77.4% of the patients was considered effective. A logistic regression analysis revealed that L5/S1 disk administration (p = 0.029; odds ratio, 5.94; 95% confidence interval, 1.20-29.45) were significantly associated with clinical effectiveness. CONCLUSIONS: Condoliase disk administration improved pain and quality of life over time. Condoliase disk administration was more effective in L5/S1 intervertebral administration.

Nerve Growth Factor in Breast Cancer Cells Promotes Axonal Growth and Expression of Calcitonin Gene-related Peptide in a Rat Model of Spinal Metastasis.

BACKGROUND/AIM: Bone metastasis commonly causes severe pain. Nerve growth factor (NGF) contributes to pain, and promotes the production of pain-associated neuropeptides, such as calcitonin gene-related peptide (CGRP), from sensory nerve endings. We hypothesized that breast cancer cells have NGF levels that promote axonal growth from dorsal root ganglia (DRGs) neurons, and increase their CGRP production associated with pain from spinal metastases. MATERIALS AND METHODS: Expression of NGF by the cultured rat breast adenocarcinoma cell line CRL-1666 was determined using an enzyme-linked immunosorbent assay (ELISA). We constructed a rat model of spinal metastasis by implanting CRL-1666 into L6 vertebrae and determined the change in CGRP expression in DRG neurons innervating vertebrae immunohistochemically. RESULTS: NGF was expressed by CRL-1666. When DRG cells were co-cultured with CRL-1666, there were more CGRP-ir neurons and with a greater average length of axon growth than in cultures without CRL-1666 (p<0.05). In the rat model of metastasis, there were more CGRP-ir DRG neurons innervating vertebra treated with CRL-1666 than in vertebrae from sham surgery control rats (p<0.05). CONCLUSION: NGF from breast cancer may mediate spinal bone pain from metastasis via axonal growth and up-regulation of pain-associated neuropeptides.

Horner's Syndrome After Anterior Decompression and Fusion for Cervical Spine Pathologies: Report of Two Cases.

Horner's syndrome is caused by impairment of the sympathetic trunk, resulting in associated ptosis, miosis, and anhidrosis. The cervical sympathetic trunk is sometimes damaged during an anterior approach to the lower cervical spine. We report two cases of Horner's syndrome after anterior decompression and fusion for lower cervical spine pathologies. Case 1 was in a 58-year-old woman with a herniated C5-6 intervertebral disc presenting myelopathy who underwent anterior cervical discectomy and fusion of C5-6. After the operation, miosis and anhidrosis of the right face occurred, and the symptoms continued for more than 15 years. Case 2 was in a 40-year-old woman whose diagnosis was flexion myelopathy with kyphosis at C5-6 and canal stenosis, so she underwent anterior cervical C5-6 discectomy and fusion of C5-6. Immediately after surgery, ptosis and miosis occurred, which lasted for four months. Horner's syndrome tends to occur during anterior cervical spine procedures, especially at the lower level, and the syndrome may be transient or irreversible. During an anterior approach to the lower cervical spine, taking care not to damage the sympathetic trunk is important to avoid this complication.

Comparison between intervertebral oblique lumbar interbody fusion and transforaminal lumbar interbody fusion: a multicenter study.

This study aimed to perform a comparative analysis of postoperative results between lumbar degenerative spondylolisthesis (LDS) treated with oblique lateral interbody fusion (OLIF) and transforaminal lumbar interbody fusion (TLIF) from the Chiba spine surgery registry database. Sixty-five patients who underwent single-level OLIF (O group) for LDS with ≥ 3 years' follow-up were retrospectively reviewed. The control group comprised 78 patients who underwent single-level TLIF (T group). The analyzed variables included global alignment, radiological parameters of fused segments, asymptomatic and symptomatic ASD incidence, clinical outcomes at 3 years postoperatively using the Japanese Orthopedic Association Back Pain Evaluation Questionnaire data, visual analogue scale scores for low back pain, lower extremity pain, and lower extremity numbness. There was no significant change in global alignment between the two groups. The rate of improvement in anterior intervertebral disc height was not significantly different between the groups at 1-month postoperatively. However, at the final evaluation, the anterior intervertebral disc height and incidence of asymptomatic ASD were significantly higher in the O group. There was no significant difference in symptomatic ASD, reoperation cases, or clinical results between groups. Thus, single-level OLIF can maintain the corrected disc height, but as it has no effect on global alignment, its benefit is limited.

An Injectable Hyaluronic Acid Hydrogel Promotes Intervertebral Disc Repair in a Rabbit Model.

STUDY DESIGN: An in vivo model to study the effect of an injectable hyaluronic acid (HA) hydrogel following puncture-induced lumbar disc injury in rabbits. OBJECTIVES: The aim of this study was to determine the efficacy of an injectable HA hydrogel to maintain disc height and tissue hydration, promote structural repair, and attenuate inflammation and innervation in the lumbar discs. SUMMARY OF BACKGROUND DATA: Previously, we have demonstrated that HA hydrogel alleviated inflammation, innervation, and pain to promote disc repair. Nevertheless, the effect of an injectable HA hydrogel in the lumbar disc in a weight-bearing animal model was not performed. METHODS: We have adopted a surgically puncture-induced disc injury at lumbar levels in a rabbit model. The discs were grouped into sham, puncture with water injection, and puncture with HA hydrogel injection. Postoperatively, we measured changes in disc height using x-ray. We used magnetic resonance imaging to assess disc degeneration on tissue hydration after euthanasia. Post-mortem, we determined histological changes, innervation (PGP9.5) and inflammation (interleukin [IL]-6, IL-1ß, and tumor necrosis factor [TNF]-α) in the discs. RESULTS: We have demonstrated a significant reduction of disc height and T2/T1ρ mapping with histological evidence of degenerative discs, increase of innervation and inflammation in puncture-induced disc injury over time. In the HA hydrogel group, disc height was increased at weeks four and eight. A slight increase of T2 mapping, but significantly in T1ρ mapping, was observed in the HA hydrogel group at week 8. We observed homogenous NP distribution and organised AF lamellae at week eight and a slight reduced innervation score in the treatment group. HA hydrogel significantly downregulated IL-6 expression at day 1. This, however, was only slightly reduced for IL-1ß and TNF-α. CONCLUSION: An injectable HA hydrogel had the protective effects in suppressing the loss of disc height, promoting tissue hydration for structural repair, and attenuating inflammation and innervation to prevent further disc degeneration.Level of Evidence: N/A.

Frequency of Adverse Drug Reactions and Analgesic Effects of Mirogabalin during Treatment of Peripheral Neuropathic Pain: A Retrospective Clinical Investigation.

INTRODUCTION: Mirogabalin should be equivalent to pregabalin, but with fewer incidences of adverse drug reactions (ADRs). To verify these benefits in actual clinical trials, our study investigated the frequency of ADRs and mirogabalin's analgesic effects during treatment of peripheral neuropathic pain. METHODS: This study included 74 patients with lower limb pain. We surveyed patient reports of ADRs during the follow-up period as the primary endpoint and examined the visual analog scale (VAS) reported for lower limb pain as the secondary endpoint (before administration, and two and four weeks after administration). RESULTS: The occurrence of ADR was 27.0%, like the frequency of ADRs in the clinical trials for other disorders. However, the discontinuation rate of administration was 10.8%, which was significantly lower than the frequency of ADR occurrences. When the analgesic effect was assessed, a significant decrease in the temporal change of VAS for lower limb pain was observed before administration, and two and four weeks after administration. CONCLUSIONS: In this study, the occurrence of ADRs reported by the patients was like the frequency of ADRs reported in the clinical trials for other disorders. When assessing the analgesic effect, the temporal change of VAS for lower limb pain was found to decrease significantly before administration, and two and four weeks after administration.

Myovascular Preserving Open-Door Laminoplasty for Cervical Spondylotic Myelopathy With Miniplate Fixation.

OBJECTIVE: Laminoplasty is an effective procedure for treating cervical spondylotic myelopathy. We conduct myovascular preserving open-door laminoplasty (MPLP) in combination with a laminoplasty plate to improve the stability of the enlarged lamina. We compare the details of the MPLP technique with conventional open-door laminoplasty. METHODS: We compared 25 cases of MPLP (mean age = 70.5, mean follow-up period = 19 months) with 15 controls who received conventional open-door laminoplasty using hydroxyapatite spacers (mean age = 74, mean follow-up period = 53 months). Regarding surgical outcomes, blood loss, operative time, Japanese Orthopaedic Association score, and postoperative visual analog score for neck pain were measured. Regarding image analysis, preoperative and postoperative range of motion (ROM), C2-7 angle, implant back out, hinge bone fusion time, presence or absence of hinge bone union failure, and posterior neck fat infiltration rate were evaluated. RESULTS: Operative time was significantly shorter for MPLP, and postoperative neck pain was significantly decreased. In image evaluation, %ROM was significantly increased in MPLP, but no difference in C2-7 angle existed between the 2 groups. Implant back out was not recognized in either group. In MPLP, the hinge union period was significantly shortened, and the postoperative fat infiltration rate was significantly decreased. CONCLUSIONS: We were able to reduce neck pain after surgery by an approach entailing longitudinal splitting of the spinous processes. We were able to ensure shorter operation times due to cervical plates and better hinge bone fusion times due to initial stability. LEVEL OF EVIDENCE: 4.

Spondylodiscitis and spinal epidural abscess related to long-term placement of an airway stent for malignant central airway obstruction.

A 70-year-old male was referred to our hospital with lower limb muscle weakness and numbness of the left hand. The patient had previously been diagnosed seven years ago with lung cancer accompanied by central airway obstruction and had received chemoradiotherapy following placement of a metallic stent. Computed tomography (CT) scan revealed an osteolytic lesion which was adjacent to the fractured stent. T2-weighted magnetic resonance imaging (MRI) demonstrated high signal intensity in the disc space. The patient was diagnosed with spondylodiscitis and spinal epidural abscess related to the airway stent. Despite hemilaminectomy, laminectomy and long-term antibiotic therapy, the infection was uncontrolled. Moreover, osteolytic destruction and kyphotic deformity progressed. Removal of the airway stent was necessary; however, it was impossible because bronchial resection was required and the risk of mediastinal injury was considered to be high. The patient subsequently received palliative care. Long-term airway stenting can cause spondylodiscitis and spinal epidural abscess. Indications for the placement of metallic stents for malignant central airway obstruction should be carefully evaluated after considering the difficulty in removal and the long-term risk of severe complications. KEY POINTS: Significant findings of the study Long-term placement and fracture of the airway stent can cause spondylodiscitis and spinal epidural abscess. What this study adds The indication of placement of a metallic stent for malignant central airway obstruction should be considered with caution, especially if long-term survival can be expected.

Radiological Assessment of Damage to the Iliopsoas Muscle by the Oblique Lateral Interbody Fusion Approach.

INTRODUCTION: There are several reports about invasive muscle injury during posterior spinal surgery. However, few reports have evaluated the association between the clinical symptoms and changes in the physical properties of the psoas major after oblique lateral interbody fusion (OLIF). Therefore, the current study aimed to investigate the relationship between the clinical symptoms and changes in the psoas major muscle before and after OLIF. METHODS: Twenty-seven patients who underwent single-level OLIF following the diagnosis of degenerative lumbar disease were included in the study. The cross-sectional areas (CSAs) of the psoas major on the approaching and contralateral sides were measured in the axial computed tomography view of the surgical intervertebral space preoperatively and postoperatively at 1 week and 3, 6, and 12 months. The preoperative and postoperative changes in the CSAs were compared. Muscle degeneration was evaluated using axial magnetic resonance images at the same level as that in the CSA evaluation preoperatively and at 12 months postoperatively. Additionally, the relationship between these parameters and postoperative lower limb symptoms was investigated. RESULTS: Significant swelling of the psoas major on the approach side was observed 1 week postoperatively (p < 0.05). No postoperative muscle degeneration was observed. Three cases of paresthesia in the front of the thigh were observed, but no association was found with changes in CSA in any of the cases. CONCLUSIONS: The OLIF approach caused swelling of the psoas major 1 week postoperatively with no more muscle degeneration in the mid-term. Although numbness of the lower limbs was found in some cases, no association was found with changes in CSA. Our study findings suggest that the OLIF approach causes temporary injury or swelling of the psoas major, but the long-term damage to the muscle is not significant.

Evaluating Spinal Canal Lesions Using Apparent Diffusion Coefficient Maps with Diffusion-Weighted Imaging.

STUDY DESIGN: Observational study. PURPOSE: To evaluate healthy volunteers and patients with spinal canal lesions using apparent diffusion coefficient (ADC) maps with diffusion-weighted imaging. OVERVIEW OF LITERATURE: Decompression surgery for lumbar spinal stenosis (LSS) is selected on the basis of subjective assessment and cross-sectional magnetic resonance imaging (MRI). However, there is no objective standard for this procedure. METHODS: We performed 3T MRI in 10 healthy volunteers and 13 patients with LSS. The ADC values in the spinal canal were evaluated at 46 vertebrae (L4/5 and L5/S1 for each participant), and the reduced and conventional fields of view were compared. RESULTS: The ADC values were 2.72±0.12 at L4/5 in healthy volunteers, 2.76±0.19 at L5/S1 in healthy volunteers, 1.77±0.58 at L4/5 in patients with LSS, and 2.35±0.29 at L5/S1 in patients with LSS. The ADC value at L4/5 in patients with LSS was significantly lower than that at L5/S1 in patients with LSS and that at L4/5 and L5/S1 in healthy volunteers (p <0.05). With an ADC cutoff value of 2.46 to identify LSS, this approach provided an area under the curve of 0.81, sensitivity of 0.92, and specificity of 0.76 (p <0.05). CONCLUSIONS: Preoperative examination using ADC maps permits visualization and quantification of spinal canal lesions, thus proving the utility of ADC maps in the selection of decompression surgery for LSS.

Objective evaluation of postoperative changes in real-life activity levels in the postoperative course of lumbar spinal surgery using wearable trackers.

BACKGROUND: Lumbar spinal disease causes disabilities in performing daily activities. Operative treatments are aimed at pain relief and rapid return to routine activity. Patient-based outcome measures are used to evaluate pathologies and therapeutic effects associated with lumbar spinal disease. Nevertheless, it remains unknown as to how much such treatment improves activity levels. The purpose of the current study was to measure changes in activity levels before and after lumbar spinal surgery using a wearable activity tracker and to analyze the differences between results and patient-based outcomes. METHODS: Sixty patients who underwent lumbar surgery were studied. The physical activity of participants was objectively evaluated using a wearable Micro-Motion logger system (Actigraph). We measured the amount of activity before and at 1, 3, 6, and 12 months after the surgery to evaluate postoperative changes. The Japanese Orthopaedic Association Back Pain Evaluation Questionnaire, Oswestry Disability Index, Roland-Morris Disability Questionnaire and visual analog scale were used to assess patient-based outcomes of pain and activities of daily living-related scores; we analyzed the relationships between scores and actual activity levels. RESULTS: The amount of actual activity decreased significantly 1 month after the surgery compared to that during the preoperative period, which then improved after 3 months postoperatively (p < 0.01). Furthermore, there was a significant improvement 6 months after the surgery compared to that during the preoperative period (p < 0.05). The changes in activity for each period were strongly correlated, regardless of the period. In contrast, a significant improvement was observed at 1 month after the surgery in almost all items of the patient-based questionnaires (p < 0.05). CONCLUSIONS: The objective activity tracker demonstrated that lumbar surgery results in the amount of activity decreasing 1 month just after surgery followed by gradual postoperative recovery within 3 months. By contrast, patient-based outcomes showed improvement in 1 month that was significantly different from the change in actual activity, indicating a gap between patient-oriented clinical scores and their actual activities.

Dual-Energy X-ray Absorptiometry and Bioelectrical Impedance Analysis are Beneficial Tools for Measuring the Trunk Muscle Mass of Patients with Low Back Pain.

INTRODUCTION: Limb muscle mass measurement using dual-energy X-ray absorptiometry (DXA) is considered the gold standard for the diagnosis of sarcopenia. Moreover, bioelectrical impedance analysis (BIA) is also recognized as a beneficial tool considering its high correlation with DXA. However, it remains to be elucidated whether DXA and BIA can accurately measure trunk lean mass. The aim of this study was to investigate the correlation between DXA and BIA measurements of trunk muscle mass and the cross-sectional area (CSA) of trunk muscles measured using magnetic resonance imaging (MRI) and to compare measures of trunk muscle mass obtained using DXA and BIA in patients with low back pain (LBP). METHODS: In total, 65 patients participated in the study. The correlation between DXA and BIA measurements and the CSA of trunk and paraspinal muscles at the L4-5 level were calculated. In addition, the correlation between DXA and BIA measurements of trunk muscle mass and the differences between these two measurements were determined. RESULTS: The correlation coefficient between DXA and BIA trunk muscle mass measurement and trunk muscle CSA was 0.74 and 0.56 for men and 0.69 and 0.44 for women, respectively. DXA and BIA measurement values showed a significantly moderate correlation with the CSA of the erector spinae (ES) and psoas major (PM). The multifidus (MF) CSA did not correlate with measurements of DXA and BIA in both men and women. Although DXA and BIA measurements were significantly correlated, a significant difference between these two measurements was found. BIA overestimated the trunk muscle mass significantly compared with DXA. CONCLUSIONS: Trunk muscle mass measured with DXA and BIA was correlated with the CSA of most trunk muscles. Although the measurement of DXA and BIA showed a high correlation, BIA overestimated trunk muscle mass compared with DXA. Both DXA and BIA are beneficial for measuring trunk muscle mass.

Comparison of the Activity Level of the Upper Limbs and Trunk in Patients with Low Back Pain Evaluated Using a Wearable Accelerometer: A Validation Study.

INTRODUCTION: Wearable accelerometers can be used to evaluate waking and sleeping movements. Although a correlation between accelerometer data captured at the wrist and waist has been reported, it has not been evaluated in patients with low back pain. Therefore, this study aimed to evaluate correlations between movement measured at the wrist and waist, using wearable accelerometers, in patients with low back pain. METHODS: Twenty patients with chronic low back pain and 20 healthy volunteers were enrolled. Two identical accelerometers were simultaneously worn by each participant, one on the nondominant wrist and the other at the waist, for 1 week. We compared the mean number of active movements and mean total amount of movement between the wrist and the waist to evaluate daytime and sleep activities. During sleep, we also evaluated sleep efficiency and time awake after sleep onset. RESULTS: In daytime activity, the mean number of active movements and mean total amount of movement was greater for the wrist than for the waist, and the amount of waist movements relative to wrist movements was significantly lower in patients with low back pain than in healthy volunteers (p < 0.05). Despite these differences, the mean number of active movements and mean total amount of movement at the wrist and waist were strongly correlated in both groups. During sleep, although there was no difference in either measured sleep efficiency at the wrist or waist or time awake after sleep onset, measurements were strongly correlated in both groups. CONCLUSIONS: A strong correlation between movement data at the wrist and waist during both daytime activities and sleep was identified in patients with low back pain. Therefore, a wearable accelerometer worn on the wrist can reliably measure the movement of patients with low back pain, simplifying data capture for clinical and research purposes and improving patient comfort.

Post-Operative Spinal Epidural Hematoma after Thoracic and Lumbar Spinous Process-Splitting Laminectomy for Thoracic and Lumbar Spinal Stenosis.

INTRODUCTION: To investigate the risk of epidural hematoma after spinous process-splitting laminectomy (SPSL). METHODS: A total of 137 cases (mean age, 72.4 years; 68 men) of SPSL were included. Of these, there were instances (3.7%; mean age, 70.5 years; all male) of postoperative development of new neurologic deficit due to epidural hematoma requiring reoperation. The 133 subjects (72.5 years; 64 men) with normal postoperative course were used as controls, and comparisons were made between both groups using chi-squared and Student's t-tests. Regarding our investigation of risk factors for epidural hematoma, logistic regression was conducted with presence or absence of hematoma as our primary outcome variable, and age, gender, disease duration, number of laminectomies, which levels were decompressed, blood loss, length of case, drain output, coagulopathy, and whether or not there was an intraoperative dural tear were our explanatory variables. RESULTS: All cases of hematoma were single-level laminectomies; there was one case of T9-10 and 3 cases of L2-3. In our direct comparison of both groups (hematoma versus control), the proportion of men was significantly higher in the hematoma group (100% versus 48%, p < 0.05); levels decompressed were also significantly higher (p < 0.05) in the hematoma group, and drain outputs were significantly lower (113 mL versus 234 mL, p < 0.05). From our logistic regression analysis, the levels were significantly higher (χ2 = 15, p = 0.0001) and the drain outputs were smaller (χ2 = 4.6, p = 0.03) in the hematoma group. CONCLUSIONS: Single-level decompression higher than the L2-3 level and reduced drain output were risk factors for spinal epidural hematoma. With this method of spinous process suturing and reconstruction there is less decompression compared with more conventional methods; therefore, the effect of hematoma may be more pronounced at higher vertebral levels with reduced canal width, and drain failure may also occur with this limited space.

Tumor Necrosis Factor-α Produced by Osteoclasts Might Induce Intractable Pain in a Rat Spinal Metastasis Model of Breast Cancer.

INTRODUCTION: Causes of pain due to spinal metastases have been insufficiently investigated. Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were the focus of this study. Both are known as proinflammatory cytokines associated with the pathophysiology of pain syndromes1 ). It is well known that cancer cells produce these cytokines, but whether osteoclasts produce them as well remains unclear. We hypothesize that osteoclasts produce these cytokines; in other words, pain from spinal metastasis is stronger than pain from the primary tumor. METHODS: We made a rat spinal metastasis model of breast cancer (metastasis group) and models with a hole in the vertebrae (puncture group) and resected the vertebrae. Tartrate-resistant acid phosphatase (TRAP) staining was performed to reconfirm that osteoclasts increase in vertebrae with spinal metastasis. We then evaluated TNF-α and IL-6 expression using immunohistochemistry and real-time polymerase chain reaction (PCR). RESULTS: The results of TRAP staining showed that osteoclasts increase in metastatic vertebrae. The osteoclasts in the puncture models were TNF-α negative but were TNF-α positive in the metastasis model. The osteoclasts in the puncture models and metastasis model were both IL-6 positive. According to the real-time PCR results, TNF-α in vertebrae increased in the metastasis model, but IL-6 did not increase in the metastasis model compared with in the puncture model. CONCLUSIONS: The number of osteoclasts is higher in the metastasis model. While TNF in the osteoclasts increased in the spinal metastasis model, IL-6 did not. This probably means that breast cancer affects TNF production in osteoclasts. This increase of TNF-α may lead to pain from spinal metastasis.