Osteophyte Bridge Formation Correlates with Vascular Calcification and Cardiovascular Disease in Diffuse Idiopathic Skeletal Hyperostosis.

Diffuse idiopathic skeletal hyperostosis (DISH) is a noninflammatory spondyloarthropathy characterized by ectopic calcification of spinal cord tissue. Its etiology is possibly polygenic. However, its pathogenesis and systemic effects remain unclear. Recent studies have reported a high prevalence of DISH in heart failure patients. The authors investigated how the incidence and severity of DISH are associated with vascular calcification and the occurrence of cardiovascular events. In this retrospective chart review study, 500 patients with cardiovascular disease who underwent surgery (cardiovascular events group) and 500 patients with non-cardiovascular disease who underwent computed tomography scans (non-cardiovascular events group) were randomly selected to investigate the degree of ossification of the anterior longitudinal ligament and the incidence of DISH. We found that the incidence of DISH was higher in patients with cardiovascular events and that patients with DISH had more calcification of the coronary arteries and aorta. Next, we examined the relationship between the degree of coronary and aortic calcification, the incidence of DISH, and the degree of ossification of the anterior longitudinal ligament in the non-cardiovascular event group. The prevalence of DISH in the cardiovascular and non-cardiovascular groups was 31.4% and 16.5%, respectively (p = 0.007). Aortic calcification and a predominant degree of vascular calcification with a certain level of ossification of the anterior longitudinal ligament suggest some correlation between DISH and cardiovascular events. This study is important in understanding the pathophysiology and pathogenesis of DISH.

Repeated intravenous infusion of mesenchymal stem cells enhances recovery of motor function in a rat model with chronic spinal cord injury.

Spinal cord injury (SCI) can cause paralysis with a high disease burden with limited treatment options. A single intravenous infusion of mesenchymal stem cells (MSCs) improves motor function in rat SCI models, possibly through the induction of axonal sprouting and remyelination. Repeated infusions (thrice at weekly intervals) of MSCs were administered to rats with chronic SCI to determine if multiple-dosing regimens enhance motor improvement. Chronic SCI rats were randomized and infused with vehicle (vehicle), single MSC injection at week 6 (MSC-1) or repeatedly injections of MSCs at 6, 7, and 8 weeks (MSC-3) after SCI induction. In addition, a single high dose of MSCs (HD-MSC) equivalent to thrice the single dose was infused at week 6. Locomotor function, light and electron microscopy, immunohistochemistry and ex vivo diffusion tensor imaging were performed. Repeated infusion of MSCs (MSC-3) provided the greatest functional recovery compared to single and single high-dose infusions. The density of remyelinated axons in the injured spinal cord was the greatest in the MSC-3 group, followed by the MSC-1, HD-MSC and vehicle groups. Increased sprouting of the corticospinal tract and serotonergic axon density was the greatest in the MSC-3 group, followed by MSC-1, HD-MSC, and vehicle groups. Repeated infusion of MSCs over three weeks resulted in greater functional improvement than single administration of MSCs, even when the number of infused cells was tripled. MSC-treated rats showed axonal sprouting and remyelination in the chronic phase of SCI.

How Much Experience is Required to Acquire the Skills to Independently Perform Spine Surgery? What Milestones are Needed for Successful Surgery?

Purpose: To assess the number of surgeries needed to acquire the necessary skills to perform spine surgery independently. Patients and Methods: A questionnaire on 12 different spinal procedures was sent to orthopedic surgeons affiliated with the spine teams of orthopedic departments at either the Akita University or Sapporo Medical University. Participants were asked to identify whether they (A) could independently perform each procedure, (B) could perform each procedure with the assistance of a senior doctor, or (C) were unable to perform each procedure. Those whose response was (A) were asked how many surgeries were required to acquire the necessary skills. Those who responded to (B) or (C) were asked how many surgeries they believed were required to acquire the skills necessary to operate independently. Participants also responded to 10 questions on surgical training techniques and rated the usefulness of each method. Results: A total of 55 spine surgeons responded to the questionnaire. Group A required significantly fewer surgeries in the following categories to become independent than required Group C: upper cervical spine surgery (7.3/19.3), anterior cervical decompression/fusion (6.7/28.8), posterior cervical decompression/fusion (9.5/27.3), lumbar discectomy (12.6/26.7), endoscopic lumbar discectomy (10.2/24.2), spinal tumor resection (6.5/37.2), and spinal kyphosis surgery (10.3/32.3). Over 80% of participants responded that the following were effective methods: "surgeries where a senior doctor is the main surgeon, and the respondent is the assistant and observer"; "surgeries where the respondent is the main surgeon, and a senior doctor is an assistant"; "self-study using surgery manuals, articles, and textbooks"; and "training through video surgery sessions". Conclusion: Surgeons who do not perform specific procedures independently require more surgical experience than those who operate independently. Our results may help develop more efficient training methods for spine surgeons.

Broad and Asymmetric Lower Extremity Myotomes: Results from Intraoperative Direct Electrical Stimulation of the Lumbosacral Spinal Roots.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: This study aimed to accurately map the lower extremity muscles innervated by the lumbar spinal roots by directly stimulating the spinal roots during surgery. SUMMARY OF BACKGROUND DATA: Innervation of the spinal roots in the lower extremities has been estimated by clinical studies, anatomical studies, and animal experiments. However, there have been discrepancies between studies. Moreover, there are no studies that have studied the laterality of lower limb innervation. MATERIALS AND METHODS: In 73 patients with lumbar degenerative disease, a total of 147 spinal roots were electrically stimulated and the electromyographic response was recorded at the vastus medialis (VM), gluteus medius (GM), tibialis anterior (TA), biceps femoris (BF), and gastrocnemius (GC). The asymmetry index (AI) was obtained using the following equation to represent the left-right asymmetry in the CMAP amplitude. Paired t-tests were used to compare CMAP amplitudes on the right and left sides. Differences in the AI among the same spinal root groups were determined using one-way analysis of variance. RESULTS: The frequency of compound muscle action potentials (CMAP) elicitation in VM, GM, TA, BF, and GC were 100%, 75.0%, 50.0%, 83.3%, and 33.3% in L3 spinal root stimulation, 90.4%, 78.8%, 59.6%, 73.1%, and 59.6% in L4 spinal root stimulation, 32.2%, 78.0%, 93.2%, 69.5%, and 83.1% in L5 spinal root stimulation, and 40.0%, 100%, 80.0%, 70.0%, and 80.0% in S1 spinal root stimulation, respectively. The most frequent muscle with maximum amplitude of the CMAP in L3, L4, L5, and S1 spinal root stimulation was the VM, GM, TA, and GM respectively. Unilateral innervation occurred at high rates in the TA in L4 root stimulation and the VM in L5 root stimulation in 37.5% and 42.3% of patients, respectively. Even in patients with bilateral innervation, a 20-38% asymmetry index of CMAP amplitude was observed. CONCLUSIONS: The spinal roots innervated a much larger range of muscles than what is indicated in general textbooks. Furthermore, a non-negligible number of patients showed asymmetrical innervation of lower limb by the lumbar spinal roots.

Degenerative Lumbar Spondylolisthesis Patients With Movement-related Low Back Pain Have Less Postoperative Satisfaction After Decompression Alone.

STUDY DESIGN: Retrospective analysis of prospectively collected multicenter observational data. OBJECTIVE: The aim was to examine the preoperative factors affecting postoperative satisfaction following posterior lumbar interbody fusion (PLIF) and microendoscopic muscle-preserving interlaminar decompression (ME-MILD) in patients with degenerative lumbar spondylolisthesis (DLS). SUMMARY OF BACKGROUND DATA: The technique involved in DLS surgery may either be decompression alone or decompression-fixation. Poor performance may occur after either of these surgical treatments. The author hypothesized that evaluating the correlation between preoperative quality of life and postoperative performance would aid in determining the optimal procedure. MATERIALS AND METHODS: This study included 138 patients who underwent surgery for 1-level mild DLS. The authors performed PLIF for 79 patients and ME-MILD for 59 patients. When the satisfaction subscale of the Zurich Claudication Questionnaire exceeded 2 points, postoperative satisfaction was considered poor. The clinical characteristics were investigated. Responses to preoperative health-related quality of life questionnaires, such as the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ), short form-36 health survey (SF-36), and visual analog scale, were compared between the satisfied and unsatisfied groups. RESULTS: In the PLIF group, no endogenous factors influenced postoperative satisfaction. The ME-MILD cohort's satisfied and unsatisfied patients differed significantly in terms of preoperative lumbar spine dysfunction ( P <0.001) items of the JOABPEQ, role physical ( P =0.03), and role emotional ( P =0.03) items of the SF-36. A strong correlation ( r =-0.609 P =0.015) was found between preoperative lumbar spine dysfunction and postoperative satisfaction. CONCLUSIONS: In the ME-MILD group, preoperative lumbar spine function was correlated with postoperative satisfaction. Decompression alone may be ineffective in cases with decreased lumbar spine function prior to surgery. The degree of low back pain on movement should be considered before selecting the surgical method. LEVEL OF EVIDENCE: 3.

Risk Factors for Postoperative Loss of Correction in Thoracolumbar Injuries Caused by High-Energy Trauma Treated via Percutaneous Posterior Stabilization without Bone Fusion.

Background and Objectives: Percutaneous pedicle screws were first introduced in 2001, soon becoming the cornerstone of minimally invasive spinal stabilization. Use of the procedure allowed adequate reduction and stabilization of spinal injuries, even in severely injured patients. This decreased bleeding and shortened surgical time, thereby optimizing outcomes; however, postoperative correction loss and kyphosis still occurred in some cases. Thus, we investigated cases of percutaneous posterior fixation for thoracolumbar injury and examined the factors affecting the loss of correction. Materials and Methods: Sixty-seven patients who had undergone percutaneous posterior fixation for thoracolumbar injury (AO classifications A3, A4, B, and C) between 2009 and 2016 were included. Patients with a local kyphosis angle difference ≥10° on computed tomography at the postoperative follow-up (over 12 months after surgery) or those requiring additional surgery for interbody fusion were included in the correction loss group (n = 23); the no-loss group (n = 44) served as the control. The degree of injury (injury level, AO classification, load-sharing score, local kyphosis angle, cuneiform deformity angle, and cranial and caudal disc injury) and surgical content (number of fixed intervertebral vertebrae, type of screw used, presence/absence of screw insertion into the injured vertebrae, and presence/absence of vertebral formation) were evaluated as factors of correctional loss and compared between the two groups. Results: Comparison between each group revealed that differences in the wedge-shaped deformation angle, load-sharing score, degree of cranial disc damage, AO classification at the time of injury, and use of polyaxial screws were statistically significant. Logistic regression analysis showed that the differences in wedge-shaped deformation angle, AO classification, and cranial disc injury were statistically significant; no other factors with statistically significant differences were found. Conclusion: Correction loss was seen in cases with damage to the cranial intervertebral disc as well as the vertebral body.

Extraforaminal Stenosis at L2-L3 Treated with Microendoscopic Surgery: Report of Two Cases.

Introduction: The many cases of far-out syndrome that have been reported have involved extraforaminal stenosis at L5-S1. We report two cases of extremely rare extraforaminal stenosis at L2-L3. Case Report 1: A 59-year-old man presented with a 1/2-year history of the right leg pain. Radiological examination revealed stenosis of the right L2 spinal nerve between the osteophyte of the vertebral body and the L3 right transverse process. The right L2 spinal nerve was decompressed with microendoscopic surgery. Postoperatively, the pain in the right lower extremity was relieved. Case Report 2: An 80-year-old man presented with a ½-year history of the right leg pain. He had undergone posterior lumbar fusion (L4-L5 and L5-S1) approximately 30 years earlier. Radiological examination revealed stenosis of the right L2 spinal nerve between the osteophyte of the vertebral body and the L3 right transverse process. The right L2 spinal nerve was decompressed with microendoscopic surgery. Postoperatively, the patient had no symptoms and his course over the next 6 months was good. Conclusions: In both cases, we performed microendoscopic decompression of the L2 spinal nerve with good post-operative results. In both our patients, extraforaminal stenosis was caused by osteophytes that formed as a result of degenerative spondylosis.

Enhanced Network in Corticospinal Tracts after Infused Mesenchymal Stem Cells in Spinal Cord Injury.

Although limited spontaneous recovery occurs after spinal cord injury (SCI), current knowledge reveals that multiple forms of axon growth in spared axons can lead to circuit reorganization and a detour or relay pathways. This hypothesis has been derived mainly from studies of the corticospinal tract (CST), which is the primary descending motor pathway in mammals. The major CST is the dorsal CST (dCST), being the major projection from cortex to spinal cord. Two other components often called "minor" pathways are the ventral and the dorsal lateral CSTs, which may play an important role in spontaneous recovery. Intravenous infusion of mesenchymal stem cells (MSCs) provides functional improvement after SCI with an enhancement of axonal sprouting of CSTs. Detailed morphological changes of CST pathways, however, have not been fully elucidated. The primary objective was to evaluate detailed changes in descending CST projections in SCI after MSC infusion. The MSCs were infused intravenously one day after SCI. A combination of adeno-associated viral vector (AAV), which is an anterograde and non-transsynaptic axonal tracer, was injected 14 days after SCI induction. The AAV with advanced tissue clearing techniques were used to visualize the distribution pattern and high-resolution features of the individual axons coursing from above to below the lesion. The results demonstrated increased observable axonal connections between the dCST and axons in the lateral funiculus, both rostral and caudal to the lesion core, and an increase in observable axons in the dCST below the lesion. This increased axonal network could contribute to functional recovery by providing greater input to the spinal cord below the lesion.

Effect of Minimally Invasive Selective Laminectomy for Cervical Spondylotic Myelopathy on Degenerative Spondylolisthesis.

STUDY DESIGN: Retrospective analysis of prospectively collected observational data. OBJECTIVE: This study aimed to evaluate the slippage, sagittal alignment, and range of motion (ROM) after selective laminectomy (SL) in patients who had cervical spondylotic myelopathy (CSM) with degenerative spondylolisthesis (DS). SUMMARY OF BACKGROUND DATA: Clinical outcomes have been reported for both decompression and fusion surgeries for DS of the lumbar spine. However, only a few reports have examined cervical spine spondylolisthesis. MATERIALS AND METHODS: This study included 178 patients who underwent SL for CSM. Those with ossification of the posterior longitudinal ligament were excluded. Slippage >2 mm was defined as spondylolisthesis, and spondylolisthesis progression was defined as an additional displacement >2 mm on a neutral radiograph. The slippage, translational motion, C2-C7 angle, local kyphosis, and ROM were examined before and ≥2 years after surgery. Radiologic parameters were evaluated according to the slip direction and the number of laminae removed. RESULTS: DS was observed in 29 patients (16.3%); 24 patients, comprising 9 and 15 in the anterolisthesis and retrolisthesis groups, respectively, were successfully followed up for more than 2 years. Preoperative and postoperative radiologic changes in slippage, translational motion, C2-C7 angle, local kyphosis, and ROM were not remarkable in either group regardless of the number of laminae removed. Revision surgery for the progression of DS and alignment deterioration was not required in any patient of either group. CONCLUSIONS: SL does not affect DS, sagittal alignment, or ROM irrespective of the slip direction and the number of laminae removed, even after >2 years after surgery. Given the preservation of the posterior elements, SL may be an effective treatment for CSM with DS. LEVEL OF EVIDENCE: Level IV.

Prevalence of Multiple-Level Spondylolysis and the Bone Union Rates among Growth-Stage Children with Lower Back Pain.

INTRODUCTION: Lumbar spondylolysis is usually single level, and only a few multiple-level cases have been reported. We investigated the frequency of multiple-level spondylolysis and the bone union rates among growth-stage children with lower back pain (LBP). METHODS: The subjects were growth-stage children examined for LBP between April 2013 and December 2018. All patients with LBP persisting for at least 2 weeks and severe enough to make playing sports difficult underwent lumbar plain radiogram, computed tomography, and magnetic resonance imaging. The cases diagnosed as multiple-level spondylolysis and classified as early or progressive stage received conservative treatment to achieve bone union. RESULTS: A total of 782 growth-stage children were examined for LBP. Of them, 243 children (31.1%) were diagnosed with lumbar spondylolysis. Of these 243 children, 23 (9.5%) children had multiple-level spondylolysis. Of the children diagnosed with multiple-level spondylolysis, most children (87.0%) had pars defects in the early or progressive stage in which bone union could be expected. Most children (78.3%) had pars defects in the terminal stage and combined with these defects, had pars defects in the early or progressive stage at a different spinal level. Twenty children diagnosed with multiple-level spondylolysis who also had pars defects in the early or progressive stage received conservative treatment for bone union, which was achieved in 31 of 39 sites (79.5%). The bone union rate by stage was 92.9% (26 of 28 sites) in the early stage and 45.5% (5 of 11 sites) in the progressive stage. CONCLUSIONS: In cases of multiple-level spondylolysis, bone union is likely to be achieved with conservative treatment when the pars defects are in the early or progressive stage. Therefore, the first choice of treatment should be conservative treatment to achieve bone union, the same for single-level spondylolysis.

Reconstruction after Subtotal Sacrectomy for Sacral Ewing's Sarcoma Using Tibial Allograft Strut Grafting: A Case Report.

We present the case of a 15-year-old girl. Two months after becoming aware of pain, she was diagnosed with a sacral tumor and referred to our department. She was diagnosed with a sacral Ewing's sarcoma; after chemotherapy, it was determined that the tumor could be resected, so surgical treatment was performed. The sacrum and ilium were partially resected at the lower end of S1, and the lumbar vertebrae and pelvis were fixed with a pedicle screw and two iliac screws on each side of L3, and the sacral resection was reconstructed with a tibial strut allograft. No tumor recurrence or metastasis has been observed 1 year postoperatively. She developed bladder and rectal dysfunction, but she remained independent in activities of daily living and her daily life was not limited. The bone fusion in the reconstructed area confirmed the lack of instrumentation looseness. Surgical treatment for sacral Ewing's sarcoma was performed to cure the patient. We believe that the tibial allograft contributed to the patient's ability to walk on her own due to its high mechanical stability. Postoperative bone healing was observed with the same material, suggesting that the tibial allograft is useful for similar procedures.

Risk Factor for Poor Patient Satisfaction After Lumbar Spine Surgery in Elderly Patients Aged Over 80 years.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To clarify the poor patient satisfaction after lumbar spinal surgery in elderly patients. SUMMARY OF BACKGROUND DATA: As the global population continues to age, it is important to consider the surgical outcome and patient satisfaction in the elderly. No studies have assessed patient satisfaction in elderly patients undergoing surgical treatment and risk factors for poor satisfaction in elderly patients after lumbar spinal surgery. MATERIALS AND METHODS: A retrospective multicenter survey was performed in 169 patients aged above 80 years who underwent lumbar spinal surgery. Patients were followed up for at least 1 year after surgery. We assessed patient satisfaction from the results of surgery by using a newly developed patient questionnaire. Patients were assessed by demographic data, surgical procedures, complications, reoperation rate, pain improvement, and risk factors for poor patient satisfaction with surgery for lumbar spinal disease. RESULTS: In total, 131 patients (77.5%, G-group) were satisfied and 38 patients (22.5%, P-group) were dissatisfied with surgery. The 2 groups did not differ significantly in baseline characteristics and surgical data. Postoperative visual analog scale score for low back pain and leg pain were significantly higher in the P-group than in the G-group (low back pain: G-group, 1.7±1.9 vs. P-group, 5.2±2.5, P<0.001; leg pain: G-group, 1.4±2.0 vs. P-group, 5.5±2.6, P<0.001). Multivariate regression analysis revealed that postoperative vertebral fracture (P=0.049; odds ratio, 3.096; 95% confidence interval, 1.004-9.547) and reoperation (P=0.025; odds ratio, 5.692; 95% confidence interval, 1.250-25.913) were significantly associated with the patient satisfaction after lumbar spinal surgery. CONCLUSIONS: Postoperative vertebral fracture and reoperation were found to be risk factors for poor patient satisfaction after lumbar spinal surgery in elderly patients, which suggests a need for careful treatment of osteoporosis in addition to careful determination of surgical indication and procedure in elderly patients. LEVEL OF EVIDENCE: Level III.

Association between Spinopelvic Alignment and Lumbar Intervertebral Disc Degeneration Quantified with Magnetic Resonance Imaging T2 Mapping in Patients with Chronic Low Back Pain.

INTRODUCTION: Although intervertebral disc degeneration (IVDD) and spinopelvic malalignment are likely key structural features of spinal degeneration and chronic low back pain (CLBP), the correlation analysis has not been fully conducted. This cross-sectional quantitative magnetic resonance imaging (MRI) T2 mapping study aimed to elucidate the association between IVDD and spinopelvic alignment in CLBP patients. METHODS: The subjects included 45 CLBP patients (19 men and 26 women; mean age, 63.8 ± 2.0 years; range, 41-79 years). The T2 values of the anterior annulus fibrosus (AF), the nucleus pulposus (NP), and the posterior AF were evaluated using MRI T2 mapping. We compared the possible correlations of spinopelvic parameters with T2 values of anterior AF, NP, and posterior AF using Pearson's correlation coefficient analysis. T2 values in these regions were classified into upper (L1-L2 and L2-L3), middle (L3-L4), and lower (L4-L5 and L5-S1) disc levels, and we analyzed the correlations with spinopelvic parameters. RESULTS: There were significant correlations of the anterior AF T2 values with lumbar lordosis (r = 0.51, p < 0.01), sacral slope (r = 0.43, p < 0.01), sagittal vertical axis (r = -0.40, p < 0.01), and pelvic tilt (r = -0.33, p < 0.01). In all lumbar levels, T2 values of anterior AF had significantly positive correlation with LL and significantly negative correlation with SVA. In lower disc level, T2 values of anterior AF had significantly positive correlation with SS and significantly negative correlation with PT. T2 values of NP and posterior AF had no significant correlations with spinopelvic parameters in all lumbar disc levels. CONCLUSIONS: In summary, this study indicated that the anterior AF degeneration is associated with hypolordosis of the lumbar spine, anterior translation of the body trunk, and posterior inclination of the pelvis in CLBP. Anterior AF degeneration in all lumbar disc levels was associated with hypolordosis of the lumbar spine and anterior translation of the body trunk. Anterior AF degeneration in lower disc level was associated with posterior inclination of the pelvis.

Glossopharyngeal and Hypoglossal Nerve Paralysis Secondary to Prevertebral Phlegmon.

A 50-year-old man presented to the clinic with severe neck pain, fever, and difficulty breathing and was subsequently admitted to the local orthopedics department with possible retropharyngeal abscess and pyogenic spondylitis. Antibiotic therapy was initiated; however, due to poor oxygenation, he was referred and transferred to our department and admitted. Magnetic resonance imaging showed signal changes at the left C1/2 lateral atlantoaxial joint, posterior pharynx, longus colli muscle, carotid space, and medial deep cervical region, predominantly on the left side. In addition, despite lymph node enlargement from the posterior pharynx to the deep cervical region, there was no abscess formation. There were no signs of a space-occupying lesion or signal changes in the jugular foramen. One day postadmission, the patient's temperature had risen to 39.1°C and his SpO2 had fallen. His neck pain had also worsened, and emergency surgery was decided. Preoperatively, we suspected retropharyngeal abscess and pyogenic spondylitis. On day 13 postadmission, the patient exhibited dysphagia, deviated tongue protrusion, and the curtain sign. Glossopharyngeal and hypoglossal nerve paralysis were diagnosed. The patient's swallowing functions recovered and he was discharged on day 36. We experienced a case of glossopharyngeal and hypoglossal nerve paralysis secondary to pyogenic cervical facet joint arthritis.

Do We Have Adequate Flexion-extension Radiographs for Evaluating Instability in Patients With Lumbar Spondylolisthesis?

STUDY DESIGN: A retrospective cohort study of consecutive patients. OBJECTIVE: To investigate whether adequate flexion-extension was acquired in standard functional radiographs in lumbar spondylolisthesis. SUMMARY OF BACKGROUND DATA: In lumbar spondylolisthesis, flexion-extension radiographs taken in the standing position are most commonly used to evaluate spinal instability. However, these functional radiographs occasionally depend on the patient's effort and cooperation, they can provide different results. METHODS: This study included 92 consecutive patients diagnosed with L4-5 degenerative lumbar spondylolisthesis. We analyzed the flexion-extension radiographs taken with the patient being led by the hand (LH) and those taken without LH (NLH). Sagittal translation (ST), segmental angulation (SA), posterior opening (PO), and lumbar lordosis (LL) were measured on functional radiographs taken in both tests. Then, ST, SA, PO, detection rate of instability, and LL observed in LH were compared with those observed in NLH. Furthermore, the correlation of the difference was evaluated between ST, lumbar angulation, and LL. RESULTS: A relative value of ST was 9.5% ±â€Š4.3% in LH and 5.6% ±â€Š3.3% in NLH, which differed significantly (P < 0.001). SA and PO were also significantly greater in LH than in NLH. The detection rate of instability was 71.7% in LH and 30.4% in NLH (P < 0.001). LL measurement on flexion showed 17.6°â€Š±â€Š13.5° in LH and 28.2°â€Š±â€Š12.2° in NLH, which differed significantly (P < 0.001). However, no significant difference was found in LL on extension between LH and NLH. There was a moderate correlation between the difference of ST, SA, PO, and LL on flexion. CONCLUSION: Flexion with physical assistance was useful for the detection of abnormal lumbar mobility. Taking radiation exposure into consideration, physical assistance such as using a table in front of a patient could lead the similar evaluation of the segmental instability. LEVEL OF EVIDENCE: 2.

Comparison of Posterior Lumbar Interbody Fusion and Microendoscopic Muscle-preserving Interlaminar Decompression for Degenerative Lumbar Spondylolisthesis With >5-Year Follow-up.

STUDY DESIGN: Retrospective analysis of prospectively collected observational multicenter data. OBJECTIVE: To compare the clinical results and rates of revision surgery after posterior lumbar interbody fusion (PLIF) and microendoscopic muscle-preserving interlaminar decompression (ME-MILD) in patients with single-level, mild degenerative lumbar spondylolisthesis (DLS) and follow-up of at least 5 years. SUMMARY OF BACKGROUND DATA: Surgery for symptomatic DLS remains controversial. Evaluating long-term results may reveal problems such as adjacent segmental diseases of the PLIF and decreased quality of life because of slippage and restenosis of the ME-MILD. METHODS: We enrolled 116 patients who underwent PLIF (79 patients) or ME-MILD (37 patients). Operative times, blood losses, surgical complications, Short-Form 36 (SF-36), Japanese Orthopedic Association (JOA) score, the JOA Back Pain Questionnaire (JOABPEQ), visual analog scales (VAS), and Zurich Claudication Questionnaire (ZCQ) were evaluated. RESULTS: PLIF was observed to require significantly longer operative times and entailed greater operative blood losses than did ME-MILD (151.1 vs. 119.9 min; 202.2 vs. 6.4 mL, respectively). Surgery-related complications were identified in 3 cases in the PLIF group and 2 cases in the ME-MILD group. Seventy-eight patients (50 and 28 patients in the PLIF and ME-MILD groups, respectively) were successfully followed-up for >5 years. The follow-up rate was 67.2%. No significant differences between the groups were found in terms of preoperative and postoperative JOA scores, postoperative JOABPEQ, VAS, or ZCQ. Significant improvements in JOA scores were observed in both groups. Significant improvements in the SF-36 were observed in all subscales except in role physical, general health, vitality, and mental health in the ME-MILD group. Revision surgical procedures were performed in 2 patients in the ME-MILD group and 4 patients in the PLIF group. CONCLUSIONS: PLIF and ME-MILD resulted in equivalent improvements in SF-36 and JOA scores. There were no differences in revision surgery rates among patients with single-level, mild DLS. LEVEL OF EVIDENCE: Level III-a retrospective analysis.

Mid-term Clinical Results of Microendoscopic Decompression for Lumbar Foraminal Stenosis.

INTRODUCTION: There have been several reports on surgical techniques involving microendoscopy or percutaneous endoscopy for treating lumbar foraminal stenosis (LFS). However, no studies have assessed the mid-term clinical results of endoscopic techniques in spite of their relatively long history. In this study, we report 20 consecutive cases of LFS treated by our microendoscopic technique focusing on clinical results with a follow-up of at least two years. METHODS: Twenty consecutive cases of LFS treated with microendoscopic decompression were followed up at 1, 2, 6, and 12 months postoperatively and annually thereafter. The patients were 14 males and 6 females, and the mean age at the time of surgery was 64.7 years. The Japanese Orthopaedic Association (JOA) score was used as the clinical outcome index. RESULTS: Of the 20 patients, 16 were monitored successfully for more than 2 years. The follow-up rate was 80.0%, and the mean follow-up period was 66.3 months. The JOA score improved from 13.8 points before surgery to 24.6 points at final follow-up. Revision fusion surgeries were performed in two cases for LFS recurrence. CONCLUSIONS: The microendoscopic technique effectively treats LFS.

Quantitative Analysis Concerning Atrophy and Fat Infiltration of the Multifidus Muscle with Magnetic Resonance Spectroscopy in Chronic Low Back Pain.

INTRODUCTION: Magnetic resonance spectroscopy (MRS) enables detailed analysis of the composition of muscular fat tissues such as intramyocellular lipids (IMCLs) and extramyocellular lipids (EMCLs). The aim of this study was to analyze the EMCL and IMCL of the multifidus muscle (Mm) using MRS in chronic low-back pain (CLBP) patients and identify their possible correlations with age, body mass index (BMI), low-back pain (LBP) visual analog scale (VAS) score, cross-sectional area (CSA), and fat infiltration of the Mm. METHODS: Eighty patients (32 men and 48 women; mean age, 64.7 ± 1.3 years; range, 22-83 years) with VAS scores >30 mm for CLBP were included. We analyzed the gender difference and the possible correlations of age, BMI, LBP VAS, CSA, and fat infiltration of the Mm with the IMCL and EMCL of the Mm. The subjects were divided into five groups as per their age range: < 40s, 50s, 60s, 70s, and 80s. We also analyzed the EMCL and IMCL of the Mm as per the fat infiltration classification. RESULTS: CSA was larger in the male group, EMCL was higher in the female group, and there was no significant difference in IMCL between the female and male groups. There was a significant positive correlation of EMCL with age (r = 0.33, p < 0.01) and BMI (r = 0.42, p < 0.01) and a significant negative correlation of EMCL with CSA (r = -0.61, p < 0.01). There was a significant positive correlation between IMCL and VAS (r = 0.43, p < 0.01). The EMCL and CSA of the Mm decreased with age, whereas fat infiltration increased with age. CONCLUSIONS: These results suggest that EMCL could indicate Mm degeneration associated with aging, and IMCL could be an effective objective indicator of CLBP. The EMCL and IMCL of the Mm may be useful prognostic markers in rehabilitation strategies.