Characterization of a Novel Model of Lumbar Ligamentum Flavum Hypertrophy in Bipedal Standing Mice.

OBJECTIVE: To explore the main causes of hypertrophied ligamentum flavum (HLF) and the possibility of using bipedal standing mouse model to simulate the pathological changes in human HLF. METHODS: Thirty-two 8-week-old C57BL/6 male mice were randomly assigned to the experimental group (n = 16) and control group (n = 16). In the experimental group, mice were induced to adopt a bipedal standing posture by their hydrophobia. The experimental mice were maintained bipedal standing for 8 h a day with an interval of 2 h to consume food and water. The control mice were placed in a similar environment without bipedal standing. Eight 18-month-old C57BL/6 male mice were compared to evaluate the LF degeneration due to aging factor. Three-dimensional (3D) reconstruction and finite element models were carried out to analyze the stress and strain distribution of the mouse LF in sprawling and bipedal standing postures. Hematoxylin and Eosin (HE), Verhoeff-Van Gieson (VVG), and immunohistochemistry (IHC) staining were used to evaluate the LF degeneration of mice and humans. RT-qPCR and immunofluorescence analysis were used to evaluate the expressions of fibrosis-related factors and inflammatory cytokines of COL1A1, COL3A1, α-SMA, MMP2, IL-1ß, and COX-2. RESULTS: The von Mises stress (8.85 × 10-2 MPa) and maximum principal strain (6.64 × 10-1 ) in LF were increased 4944 and 7703 times, respectively, in bipedal standing mice. HE staining showed that the mouse LF area was greater in the bipedal standing 10-week-old group ([10.01 ± 2.93] × 104 µm2 ) than that in the control group ([3.76 ± 1.87] × 104 µm2 ) and 18-month-old aged group ([6.09 ± 2.70] × 104 µm2 ). VVG staining showed that the HLF of mice (3.23 ± 0.58) and humans (2.23 ± 0.31) had a similar loss of elastic fibers and an increase in collagen fibers. The cell density was higher during the process of HLF in mice (39.63 ± 4.81) and humans (23.25 ± 2.05). IHC staining showed that the number of α-SMA positive cells were significantly increased in HLF of mice (1.63 ± 0.74) and humans (3.50 ± 1.85). The expressions of inflammatory cytokines and fibrosis-related factors of COL1A1, COL3A1, α-SMA, MMP2, IL-1ß, and COX-2 were consistently higher in bipedal standing group than the control group. CONCLUSION: Our study suggests that 3D finite element models can help analyze the abnormal stress and strain distributions of LF in modeling mice. Mechanical stress is the main cause of hypertrophied ligamentum flavum compared to aging. The bipedal standing mice model can reflect the pathological characteristics of human HLF. The bipedal standing mice model can provide a standardized condition to elucidate the molecular mechanisms of mechanical stress-induced HLF in vivo.

Impact of lumbar fusion on sitting spinopelvic balance: Multisegmental versus monosegmental.

OBJECTIVES: To compare the differences in sagittal spinopelvic parameters between patients receiving monosegmental or multisegmental lumbar fusion and to assess the impact of fusion length on sitting balance. METHODS: The current study recruited 41 patients who had undergone lumbar fusion, consisting of 18 in the monosegmental group and 23 in the multisegmental group. And the control group included 50 lumbar degenerative patients who had no previous spinal fusion surgery. Spinopelvic parameters of patients were assessed: sagittal vertical axis, pelvic tilt, sacral slope, pelvic incidence, thoracic kyphosis, lumbar lordosis, and proximal femur angles. RESULTS: We observed significant differences in sitting TK (P = 0.031), LL (P = 0.012), PT (P = 0.009) and SVA (P = 0.009) among the three groups. When transitioning from standing to sitting, the multisegmental group had the least change in SVA (P = 0.016), PT (P = 0.043), and LL (P = 0.009), with a compensatory increase in TK (P = 0.021). Moderate to strong correlations were found between the change in the LL and those in the SVA (r = -0.548, P = 0.001), PT (r = -0.600, P = 0.001), and SS (r = 0.623, P = 0.001). CONCLUSION: Multisegmental lumbar fusion significantly limits the lumbar mobility and affects the ability to compensate postural changes. Reducing the fusion segments as much as possible is of particular value in preserving lumbar mobility and maintaining the compensatory mechanism of spinopelvis.

Outcomes of lumbar spinal fusion in super-elderly patients aged 80 years and over: Comparison with patients aged 65 years and over, and under 80 years.

ABSTRACT: Despite the increasing prevalence of spinal surgery in super-elderly (SE) patients, the outcomes and complication rates have not been fully elucidated. The purpose of this study was to compare the outcomes and complications of lumbar spinal fusion for degenerative lumbar spinal stenosis (DLSS) in SE patients aged 80 years and over with those in patients aged 65 years and over, and under 80 years.This study analyzed 160 patients who underwent spinal fusion for DLSS between January 2011 and November 2019. Thirty patients in the SE group (group SE, ≥80 years) and 130 patients in the elderly group (group E, ≥65 years and <80 years) were enrolled. The performance status was evaluated by preoperative American society of anesthesiologists (ASA) score. Visual analog scales for back pain (VAS-BP) and leg pain (VAS-LP), and Korean Oswestry disability index (K-ODI) were used to assess clinical outcomes preoperatively and 1 year postoperatively. Percent changes of VAS-BP, VAS-LP and K-ODI were also analyzed. Fusion rates were evaluated by computed tomography 6 months and 1 year postoperatively. Furthermore, bone mineral density, operative time, estimated blood loss, blood transfusion, hospital days, hospitalization in intensive care unit and postoperative complications were compared.The average age of group SE was 82.0 years and that of group E was 71.6 years. There were no differences in preoperative ASA score, preoperative or postoperative VAS BP and VAS-LP, bone mineral density, operative time, estimated blood loss, blood transfusion, hospital days, hospitalization in intensive care unit and fusion rates between the groups. Preoperative and postoperative K-ODI were higher in group SE than group E (all P < .05). However, percent changes of VAS-BP, VAS-LP and K-ODI showed no significant differences. Overall early and late complications were not significantly different between the groups; however postoperative delirium was more common in group SE than group E (P = .027). SE status was the only risk factor for postoperative delirium with odds ratio of 3.4 (P = .018).Spinal fusion surgery is considerable treatment to improve the quality of life of SE patients with DLSS, however careful perioperative management is needed to prevent postoperative delirium.

Comparison of walking variations during treadmill walking test between neurogenic and vascular claudication: a crossover study.

BACKGROUND: Lumbar spinal stenosis (LSS) and peripheral arterial disease (PAD) are two distinct conditions characterized by similar symptoms including leg pain and walking limitations due to claudication. Differentiation between both origins can be difficult and characteristics such as symptom manifestations, time to relief in rest position and pain localization should be considered when determining diagnosis and the treatment plan. The objectives of this study were to compare changes in walking time to symptom change during treadmill tests and self-reported outcomes measures related to claudication, kinesophobia and global health between individuals with LSS, PAD and non-specific low back pain (nLBP). METHOD: Fifty-five patients (23 with LSS, 14 with PAD and 18 with nLBP) were recruited from May 2018 to March 2020 to complete a treadmill walking test involving two 5-min walking tasks (Upright and Forward Leaning Trunk (FLT) Walking tasks). The speed was set at 1.9 km/h (1.2 mph), and each task was followed by a 5-min rest period. Walking time to symptom change and Total walking time were recorded during each walking task. Patients were asked to complete four questionnaires related to the impact of claudication, walking impairment, kinesiophobia and global health. One-way ANOVAs were performed to compare walking time difference from the Upright to the FLT walking tasks and to compare questionnaires results between groups. RESULTS: One-way ANOVAs showed a significant difference between groups regarding difference in Walking time to symptom change between both tasks (F = 4.12, p = 0.022). The LSS group improved its Walking time to symptom change from the Upright to the FLT walking tasks more than the PAD (p = 0.34) and the nLBP group (p = 0.12). The nLBP group was less impacted by claudication and less impaired during walking compared to the LSS and PAD groups (ps < 0.001). The nLBP group also had less kinesiophobia than the LSS one (p < 0.001), but was similar to the PAD group. The global health rating was not statistically different between groups (p = 0.118). CONCLUSION: The test was able to distinguish neurogenic from vascular or nLBP related claudication. However, further studies are needed to validate this new treadmill walking test. TRIAL REGISTRATION: clinicaltrials.gov ( NCT04058171 ), Registered August 15, 2019 -Registered during recruitment.

Diagnostic Implication and Clinical Relevance of Dermatomal Somatosensory Evoked Potentials in Patients with Radiculopathy: A Retrospective Study.

Objective: Dermatomal somatosensory evoked potentials (DSEPs) are used to evaluate abnormalities of the somatosensory tract. There have been some studies on the diagnostic value of DSEP in radiculopathy, but it is still controversial. The purpose of our study is to evaluate the diagnostic implication and clinical relevance of DSEPs in patients with radiculopathy by comparing DSEP findings to radiculopathy symptoms and intervertebral foramen (IVF) or spinal canal stenosis in lumbar magnetic resonance imaging (MRI). Methods: This retrospective study reviewed the medical records of patients (n = 59) who were examined by DSEP (each L4 and L5 dermatome) and lumbar MRI. Radiculopathy symptoms and DSEPs results were compared. For the evaluation of IVF and spinal canal size, sagittal (each bilateral L4/5 and L5/S1 IVF) and axial MR images were selected at the most stenotic level. The sizes of the IVF and spinal canal were measured by the pixel counts of selected MR images. In addition, stenosis severity was morphologically graded on a 4-point scale. DSEP results were compared with the size and grade of the IVF or spinal canal stenosis. Results: DSEPs showed high sensitivity for radiculopathy symptoms. The IVF size at L4/5 and L5/S1 (pixel counts) was significantly related to either L4 or L5 dermatomal somatosensory pathway dysfunction, respectively. However, spinal stenosis (pixel counts and grade) and IVF stenosis grade were not significantly related to DSEPs. Conclusion: This paper could be helpful in the electrophysiologic diagnosis of lumbar radiculopathy.

Relationship between Scheuermann disease and symptomatic thoracic spinal stenosis: A retrospective study.

OBJECTIVE: This study aimed to investigate the possible relationship between Scheuermann disease (SD) and the pathophysiological factors of thoracic spinal stenosis (TSS), including ossification of the ligamentum flavum (OLF), ossification of the posterior longitudinal ligament (OPLL), and thoracic disc herniation (TDH) in patients with symptomatic TSS. METHODS: Demographic and radiological data from 66 consecutive patients diagnosed with symptomatic TSS from 2013 to 2018 were retrospectively collected and divided into 3 groups depending on the underlying pathomechanism of TSS: TDH group (18 patients; 6 women; mean age ± standard deviation [Sd] = 59.89 ± 11.34), OPLL group (12 patients; 8 women; mean age ± Sd = 56.08 ± 14.74), and OLF group (36 patients; 20 women; mean age ± Sd = 58.69 ± 9.77). A total of 41 age-matched healthy individuals (19 women; mean age ± Sd = 54.88 ± 13.63) were designated as the control group. In each group, both typical and atypical SD criteria were radiologically examined. The demographic data and presence of SD between the control group and 3 subgroups of TSS pathomechanisms were evaluated. RESULTS: SD characteristics were identified in 83.33% (15/18) of patients in the TDH group, 44.44% (16/36) in the OLF group, 25% (3/12) in the OPLL group, and 17.07% (7/41) of the control individuals. When analyzed by the chi-squared test and logistic regression analysis, the presence of SD was significantly associated with TDH (P < 0.01) and OLF (P < 0.05) but not OPLL (P > 0.05). Patients with TDH and OLF showed peak involvement of T10/11, and patients with OPLL did not. Furthermore, we determined that age, sex, body-mass index, and smoking status were not the risk factors for TDH, OPLL, and OLF (P > 0.05). SD was found to be a risk factor for TDH (P < 0.01) and OLF (P < 0.05) but not for OPLL (P > 0.05). CONCLUSION: Evidence from this study indicated that SD might be a risk factor for OLF and TDH but not for OPLL.

Effectiveness of an exercise-based prehabilitation program for patients awaiting surgery for lumbar spinal stenosis: a randomized clinical trial.

Lumbar spinal stenosis is the most common reason for spine surgery in older adults, but the effects of prehabilitation on perioperative outcomes among these patients have not been investigated. This study aims to evaluate the effectiveness of a preoperative exercise-based intervention program compared with usual care on the improvement of clinical status, physical capacities and postoperative recovery of patients awaiting surgery for lumbar spinal stenosis. Sixty-eight participants were randomised to receive either a 6-week supervised exercise-based prehabilitation program or hospital usual care. The outcomes included both clinical and physical measures. Data collection occurred at post-intervention, and 6 weeks, 3- and 6-months post-surgery. Significant but small improvements were found in favour of the experimental group at the post-intervention assessment for pain intensity, lumbar spinal stenosis-related disability, lumbar strength in flexion, low back extensor muscles endurance, total ambulation time, and sit to stand performance. A significant difference in favor of the intervention group was found starting at the 3-month postoperative follow-up for low back-related disability. No adverse events were reported. Exercise-based prehabilitation did not improve short-term postoperative recovery in patients with lumbar spinal stenosis.

The impact of sagittal imbalance on walking in patients with lumbar spinal canal stenosis.

PURPOSE: Gait and posture disorder severely impedes the quality of life of affected patients with lumbar spinal canal stenosis (LSCS). Despite the major health concern, there is a paucity of literature about the relationships among spatiotemporal gait parameters and spinal sagittal parameters. This is a cross sectional study performed in a single tertiary referral center to determine the relationships among spatiotemporal gait parameters and spinal sagittal parameters in patients with LSCS. METHODS: A total of 164 consecutive patients with LSCS, 87 men and 77 women with mean age of 70.7 years, were enrolled. Spatiotemporal gait parameters were studied using a gait analysis system. Spinal sagittal parameters were studied including sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS), pelvic inclination (PI), and pelvic tilt (PT) both in the neutral and stepped positions. RESULTS: SVA was significantly larger in the stepped position than in the neutral position (neutral position, 72.5 mm; stepped position, 96.8 mm; p = 0.003). Parameters regarding the pelvis exhibited significant differences, which could represent pelvic anteversion in the stepped position. By stepwise multiple regression analysis, the prediction models, containing SVA (neutral) and PT (stepped) for double supporting phase, exhibited statistical significance, and accounted for approximately 50% of the variance. CONCLUSIONS: The present study provides statistically established evidence of correlation among spatiotemporal gait parameters and spinal sagittal parameters. Differences between sagittal parameters in neutral and stepped position may stand for the postural control during gait cycle, and increased SVA in neutral position and increased PT in stepped position may correlate with prolonged double supporting phase.

Responsiveness of Outcome Measures in Nonsurgical Patients with Lumbar Spinal Stenosis: A Secondary Analysis From a Randomized Controlled Trial.

STUDY DESIGN: Secondary analysis from a randomized controlled trial on nonsurgical interventions for patients with lumbar spinal stenosis (LSS). OBJECTIVE: The aim of this study was to assess the responsiveness of the Self-Paced Walking Test (SPWT), Swiss Spinal Stenosis Questionnaire (SSS), and Oswestry Disability Index (ODI) and determine their minimal clinically important differences (MCID) in nonsurgical LSS patients. SUMMARY OF BACKGROUND DATA: Limited information is available about the responsiveness of these tests in nonsurgical LSS population. METHODS: A total of 180 participants completed the SPWT, SSS, and ODI at baseline, 2, and 6 months. Responsiveness was assessed by distribution-based method, including effect size and standardized response mean, and anchor-based method, using the patient global index of change (PGIC) as the external anchor to distinguish responders and non-responders. Areas under the curve (AUC) were calculated along with MCIDs for "minimal" and "moderate improvement" subgroups. RESULTS: The following values represent 2- and 6-month analyses of each outcome measure, respectively. Standard effect sizes: 0.48 and 0.50 for SPWT, -0.42 and -0.36 for SSS, and -0.29 and -0.25 for ODI. Spearman correlation coefficients between PGIC and outcomes were: 0.44 and 0.39 for SPWT, -0.53 and -0.55 for SSS, and -0.46 and -0.54 for ODI. MCIDs for the "minimal improvement" subgroup were: 375.9 and 319.3 ms for SPWT, -5.3 and -5.8 points for SSS, and -9.3 and -10.8 points for ODI. AUCs was 0.68 to 0.76. MCIDs for the "moderate improvement" subgroup were: 344.2 and 538.2 m for SPWT, -5.5 and -7.5 points for SSS, and -9.1 and -13.6 points for ODI. AUCs ranged from 0.68 to 0.76. CONCLUSION: The SPWT, SSS, and ODI are responsive outcome measures to assess nonsurgical patients with LSS. This finding, along with the reported MCIDs, can help clinicians to monitor changes in their patients' walking and physical function over time and make clinical decisions. They also provide researchers with reference for future studies in LSS.Level of Evidence: 2.

The Restless Spinal Cord in Degenerative Cervical Myelopathy.

BACKGROUND AND PURPOSE: The spinal cord is subject to a periodic, cardiac-related movement, which is increased at the level of a cervical stenosis. Increased oscillations may exert mechanical stress on spinal cord tissue causing intramedullary damage. Motion analysis thus holds promise as a biomarker related to disease progression in degenerative cervical myelopathy. Our aim was characterization of the cervical spinal cord motion in patients with degenerative cervical myelopathy. MATERIALS AND METHODS: Phase-contrast MR imaging data were analyzed in 55 patients (37 men; mean age, 56.2 [SD,12.0] years; 36 multisegmental stenoses) and 18 controls (9 men, P = .368; mean age, 62.2 [SD, 6.5] years; P = .024). Parameters of interest included the displacement and motion pattern. Motion data were pooled on the segmental level for comparison between groups. RESULTS: In patients, mean craniocaudal oscillations were increased manifold at any level of a cervical stenosis (eg, C5 displacement: controls [n = 18], 0.54 [SD, 0.16] mm; patients [n = 29], monosegmental stenosis [n = 10], 1.86 [SD, 0.92] mm; P < .001) and even in segments remote from the level of the stenosis (eg, C2 displacement: controls [n = 18], 0.36 [SD, 0.09] mm; patients [n = 52]; stenosis: C3, n = 21; C4, n = 11; C5, n = 18; C6, n = 2; 0.85 [SD, 0.46] mm; P < .001). Motion at C2 differed with the distance to the next stenotic segment and the number of stenotic segments. The motion pattern in most patients showed continuous spinal cord motion throughout the cardiac cycle. CONCLUSIONS: Patients with degenerative cervical myelopathy show altered spinal cord motion with increased and ongoing oscillations at and also beyond the focal level of stenosis. Phase-contrast MR imaging has promise as a biomarker to reveal mechanical stress to the cord and may be applicable to predict disease progression and the impact of surgical interventions.

Rare case of osteomyelitis caused by Gardnerella vaginalis and Streptococcus parasanguinis in a postmenopausal woman.

Vertebral osteomyelitis is an infection of the vertebrae that can lead to spinal degeneration, most commonly caused by Staphylococcus aureus Here, we report an unusual case of pyogenic osteomyelitis caused by Gardnerella vaginalis and Streptococcus parasanguinis in a 61-year-old postmenopausal woman. The patient presented with a 2-week history of worsening lower back pain and fever and a recent episode of cystitis following re-engagement of sexual activity. Imaging revealed a deterioration of vertebrae discs and spinal canal stenosis at the L3-L4 levels with a formation of abscess in the right psoas muscle. Needle aspiration of the abscess identified G. vaginalis and S. parasanguinis and the patient was successfully treated with a 6-week course of ceftriaxone and metronidazole. This case describes an unusual coinfection of two pathogens that normally reside in the urogenital tract and oral cavity, respectively, and highlights the risk posed when these organisms breach the body's normal barriers.

Supervised physical therapy versus unsupervised exercise for patients with lumbar spinal stenosis: 1-year follow-up of a randomized controlled trial.

OBJECTIVE: To compare the 1-year outcomes of patients with lumbar spinal stenosis treated with supervised physical therapy or unsupervised exercise. DESIGN: A single-center randomized controlled trial with concealed allocation, blinded assessor and intention-to-treat analysis. SETTING: Spine care center. SUBJECTS: A total of 86 patients presenting with symptoms of neurogenic claudication caused by lumbar spinal stenosis. INTERVENTIONS: The physical therapy group received supervised physical therapy sessions twice a week for 6 weeks and home exercise program. The home exercise group received 6-week home exercise program only. MAIN MEASURES: The primary outcome was symptom severity on the Zurich claudication questionnaire at 1 year. Secondary outcomes included physical function, pain, health-related quality of life and the surgery rate after 1 year. RESULTS: At 1 year, more patients in the physical therapy group than in the home exercise group achieved minimum clinically important differences in Zurich claudication questionnaire symptom severity (60.5% vs 32.6%; adjusted odds ratio [AOR] 4.3, [95% CI [1.5-12.3], P = 0.01); Zurich claudication questionnaire physical function (55.8% vs 32.6%; AOR 3.0 [1.1-8.1], P = 0.03); SF-36 bodily pain (48.8% vs 25.6%; AOR 2.8 [1.1-7.3], P = 0.03), and SF-36 general health (20.9% vs 7.0%; AOR 6.1 [1.1-33.0], P = 0.04). The surgery rate at 1 year was lower in the physical therapy than in the home exercise group (7.0% vs 23.3%; AOR 0.2 [0.04-0.9] P = 0.04). CONCLUSIONS: Supervised physical therapy produced greater improvements in symptom severity and physical function than unsupervised exercise and was associated with lower likelihood of receiving surgery within 1 year.

Grinding trajectory generator in robot-assisted laminectomy surgery.

PURPOSE: Grinding trajectory planning for robot-assisted laminectomy is a complicated and cumbersome task. The purpose of this research is to automatically obtain the surgical target area from the CT image, and based on this, formulate a reasonable robotic grinding trajectory. METHODS: We propose a deep neural network for laminae positioning, a trajectory generation strategy, and a grinding speed adjusting strategy. These algorithms can obtain surgical information from CT images and automatically complete grinding trajectory planning. RESULTS: The proposed laminae positioning network can reach a recognition accuracy of 95.7%, and the positioning error is only 1.12 mm in the desired direction. The simulated surgical planning on the public dataset has achieved the expected results. In a set of comparative robotic grinding experiments, those using the speed adjustment algorithm obtained a smoother grinding force. CONCLUSION: Our work can automatically extract laminar centers from the CT image precisely to formulate a reasonable surgical trajectory plan. It simplifies the surgical planning process and reduces the time needed for surgeons to perform such a cumbersome operation manually.

Motor Unit Number Index in Evaluating Patients With Lumbar Spinal Stenosis.

OBJECTIVE: Motor unit number index is a quantitative electrophysiological measure that provides an index of the number of motor neurons supplying a muscle. The aim of this exploratory study was to assess the utility of motor unit number index in the evaluation of patients with lumbar spinal stenosis. DESIGN: Participants were assigned to three groups: clinical and radiological lumbar stenosis (lumbar spinal stenosis with neurogenic intermittent claudication), group A; radiological lumbar spinal stenosis without neurogenic intermittent claudication, group B; and a control group, group C. Patients self-rated their pain and functional disability using the numerical rating scale and a series of functional questionnaires. An electromyographer performed nerve conduction tests, electromyography, and motor unit number index testing. RESULTS: Seventeen patients completed the study. There were 9, 5, and 3 patients in groups A, B, and C, respectively. There were no discernable differences in motor unit number index values of any individual muscle or combined motor unit number index score between the three groups. Motor unit number index values did not correlate to pain/functional measures. CONCLUSIONS: In this exploratory study, motor unit number index did not demonstrate discriminatory ability between patients with lumbar spinal stenosis and was not correlated with pain and functional measures. Further study is needed to explore motor unit number index's role in longitudinal evaluation of patients with the clinical syndrome of lumbar spinal stenosis.

The effects of differences on sagittal kinematics and muscle coordination during step up and step down in patients with spinal stenosis.

BACKGROUND AND OBJECTIVE: Lumbar spinal stenosis (LSS) is a common spinal disorder that causes patients to assume a forward-trunk posture. Spinal alignment affects swing limb angles and stance limb muscle activities. Therefore, we investigated the effects of differences in step up (SU) and step down (SD) tasks on the kinematics of the trunk and swing limb as well as stance limb muscle coordination in patients with LSS. METHODS: Nine elderly female patients diagnosed with LSS were recruited for this study. The sagittal kinematics of the trunk and swing limb and isolated contraction ratio of the gluteus medius (GMed) and vastus lateralis (VL) during SU and SD tasks were measured using a motion analysis system and surface electromyography system. RESULTS: Thoracic (17.71∘± 7.77∘) and spine angles (13.64∘± 11.34∘) as well as swing hip (48.48∘± 12.76∘) and pelvic angles (7.52∘± 10.33∘) were significantly greater during SU than SD (10.14∘± 8.41∘, 10.03∘± 11.03∘, 29.42∘± 10.57∘, 3.21∘± 10.11∘, all P< 0.05, respectively). The isolated contraction ratio of the GMed of the stance limb (34.12% ± 13.28%) was significantly higher during SU than during SD (26.65% ± 10.02%), whereas that of the VL of the stance limb (65.88% ± 13.28%) was significantly lower during SU than during SD (73.35% ± 10.02%, P= 0.011 for both comparisons). CONCLUSIONS: Patients with LSS demonstrated trunk compensatory mechanisms to address swing hip and knee angles. Trunk position affected pelvic limb muscle coordination in the standing support limb. These findings demonstrate that SD are more challenging than SU for patients with LSS, possibly due to reduced ability to generate adequate leg extensor muscular output to safely control the motion of the body's center of mass. Therefore, trunk positions must be considered when patients with LSS undergo rehabilitation programs, particularly those involving SD or descending stairs, so that healthcare professionals can better assist patients with LSS. In addition, this study provides a background for further studies.

Association of Lumbar Spinal Stenosis with Severe Disability and Mortality Among Community-Dwelling Older Adults: The Locomotive Syndrome and Health Outcomes in the Aizu Cohort Study.

STUDY DESIGN: This prospective cohort study analyzed data from the Locomotive Syndrome and Health Outcomes in the Aizu Cohort Study. OBJECTIVE: To investigate the association between lumbar spinal stenosis (LSS) and severe disability and mortality among community-dwelling older adults. SUMMARY OF BACKGROUND DATA: Only a few studies have investigated LSS longitudinally, and the study participants were limited to selected patients diagnosed with LSS during a hospital visit. Additionally, the prognosis of LSS remains unclear. METHODS: We enrolled independent community-dwelling older adults aged 65 years or older at the time of a baseline health checkup in 2008. LSS was diagnosed using a validated diagnostic support tool for LSS. The primary endpoint was a composite of severe disability (long-term care insurance certification grade 4 or 5) and mortality. We used 1 minus Kaplan-Meier failure estimates and the log-rank test to compare the interval between baseline and the predetermined endpoint as well as a Cox proportional hazards model to estimate hazard ratios (HRs) for the LSS group with adjustment for possible confounders. Multiple imputation by chained equations was performed for sensitivity analysis. RESULTS: Of 2058 subjects enrolled, 1560 did not have missing covariates; 269 (17%) were diagnosed with LSS. After a median follow-up of 5.8 years, the rates of severe disability and mortality were 0.022 per year in subjects with LSS and 0.012 per year in those without (P = 0.006). The adjusted HR for the composite endpoint in the LSS group was 1.55 (95% confidence interval [CI], 1.01-2.38). A similar association was observed after multiple imputation of missing covariates (adjusted HR, 1.51 [95% CI, 1.06-2.16]). CONCLUSION: LSS was associated with severe disability and mortality in community-dwelling older adults. Detection of adults with LSS in the community may contribute to local health promotion.Level of Evidence: 2.

Development of a new patient-reported outcome measure assessing activities and participation in people with lumbar spinal stenosis: The Cochin Spinal Stenosis 19-item questionnaire.

BACKGROUND: Lumbar spinal stenosis (LSS) is the leading cause of spinal surgery in people over 65-years old. In people with LSS, generic self-administered questionnaires are the most commonly used PROs to assess health-related quality of life, global activity limitation, and low back pain-located activity limitation. AIM: The aim was to develop a new patient-reported outcome measure assessing activities and participation in people with LSS. DESIGN: Observation, prospective and qualitative study. SETTING: For the qualitative study, were enrolled in- and outpatients with LSS from 2 French tertiary care centers (Department of PRM of Cochin Hospital and Department of Rheumatology of Limoges Hospital). For the Internet E-survey, screened the electronic medical records of the Department of PRM of Cochin Hospital. POPULATION: From February to April 2018 were enrolled patients older than 50-years and symptomatic LSS. METHODS: We used a 2-step approach. In a first step, we conducted a qualitative study using in-depth semi-structured interviews in 20 patients with LSS to collect meaningful concepts and to develop a provisional questionnaire. In a second step, using the provisional questionnaire, we conducted an Internet E-survey in an independent sample of 200 patients with LSS. RESULTS: Concepts collected from patients generated a 48-item provisional questionnaire. Overall, 63/200 (31.5%) patients completed the provisional questionnaire. Item reduction resulted in a 19-item questionnaire, the Cochin Spinal Stenosis 19-item (CSS-19) questionnaire. Principal component analysis extracted 3 factors. In confirmatory analysis, factor 1 influenced all items. We found convergent validity with low back pain, LSS-specific disability and divergent validity with mental health-related quality of life. Cronbach α coefficient (95% CI) was 0.96 (0.94; 0.97). ICC was 0.90 (0.70; 0.97). Bland and Altman analysis found no systematic trend for test-retest. CONCLUSIONS: CSS-19 is a new patient-reported outcome measure assessing activities and participation in people with LSS. Its construction prioritized patients' perspectives at all stages. Its content and construct validities are good. CLINICAL REHABILITATION IMPACT: Instruments able to capture specific needs of people with LSS in terms of activities and participation are lacking.

Long-Term Outcomes Following Lumbar Microendoscopic Decompression for Lumbar Spinal Stenosis with and without Degenerative Spondylolisthesis: Minimum 10-Year Follow-Up.

OBJECTIVE: To determine whether preoperative presence of degenerative lumbar spondylolisthesis (DS) worsens the minimum 10-year outcome of patients undergoing microendoscopic decompression (MED) for lumbar spinal stenosis (SS). METHODS: Eighty patients undergoing MED were classified into 2 groups: DS group (34 SS with DS patients) and SS group (46 SS without DS patients). The degrees of improvement (DOIs) by the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and intensities of improvement (IOIs) by Visual Analog Scale (VAS) at 120-159 (mean, 138.4) months after MED of the DS and SS groups were statistically compared. Patients with DS were classified into 2 groups based on the effectiveness by VAS or JOABPEQ: effective group (E group: IOI or DOI ≥20) and ineffective group (I group). All preoperative radiologic measurements were statistically compared between the E and I groups. RESULTS: Significant decreases in low back pain, leg pain, and numbness, as measured by VAS, were noted at follow-up in the DS and SS groups. The effectiveness rates of pain-related disorders, lumbar spine dysfunction, and gait disturbance by JOABPEQ were almost equally high in the DS and SS groups. Statistical comparisons of the DOIs in all 5 functional scores and IOIs in low back pain, leg pain, and numbness showed no significant differences between the DS and SS groups. No significant differences were confirmed between the E and I groups concerning preoperative spondylolisthesis and instability. CONCLUSIONS: Our study indicated that preoperative DS did not worsen the outcome of patients with SS undergoing MED.

Effect of different designs of interspinous process devices on the instrumented and adjacent levels after double-level lumbar decompression surgery: A finite element analysis.

Recently, various designs and material manufactured interspinous process devices (IPDs) are on the market in managing symptomatic lumbar spinal stenosis (LSS). However, atraumatic fracture of the intervening spinous process has been reported in patients, particularly, double or multiple level lumbar decompression surgery with IPDs. This study aimed to biomechanically investigate the effects of few commercial IPDs, namely DIAMTM, CoflexTM, and M-PEEK, which were implanted into the L2-3, L3-4 double-level lumbar spinal processes. A validated finite element model of musculoskeletal intact lumbar spinal column was modified to accommodate the numerical analysis of different implants. The range of motion (ROM) between each vertebra, stiffness of the implanted level, intra stress on the intervertebral discs and facet joints, and the contact forces on spinous processes were compared. Among the three implants, the Coflex system showed the largest ROM restriction in extension and caused the highest stress over the disc annulus at the adjacent levels, as well as the sandwich phenomenon on the spinous process at the instrumented levels. Further, the DIAM device provided a superior loading-sharing between the two bridge supports, and the M-PEEK system offered a superior load-sharing from the superior spinous process to the lower pedicle screw. The limited motion at the instrumented segments were compensated by the upper and lower adjacent functional units, however, this increasing ROM and stress would accelerate the degeneration of un-instrumented segments.

Spinous Process Inclination in Degenerative Lumbar Spinal Stenosis Individuals.

The aim of this study is to determine the sagittal inclination of lumbar spinous processes (SPs) in individuals with degenerative lumbar spinal stenosis (DLSS). It is a retrospective computerized tomography (CT) study including 345 individuals divided into two groups: control (90 males, 90 females) and stenosis (80 males and 85 females. The SP inclination was measured in the midsagittal plane from L1 to L5 levels. Stenosis males (L3-L5) and females (L1, L4) manifested significantly greater SP inclination compared to their counterparts in the control group. Males had significantly horizontal SP orientation compared to females (L1, L2). We also found that SP inclination became steeper as we descend caudally. This study indicates that SP inclinations are significantly associated with DLSS.