Impact of pelvic anteversion on spinopelvic alignment in an asymptomatic population: a dynamic perspective of standing and sitting.

BACKGROUND CONTEXT: A subgroup of patients with pelvic anteversion can present with an unusually large degree of lumbar lordosis (LL), a highly sloped sacrum, and a relatively small pelvic incidence (PI). Prior to lumbar surgery, it can be important to consider such unique sagittal alignment. However, until now, there has been a lack of a predictive model considering different pelvic alignments. Furthermore, the dynamic characteristics of an anteverted pelvis (AP) subgroup have also been unclear. PURPOSE: To build linear predictive formulas for LL that take pelvic anteversion into consideration and to explore the dynamic characteristics of an AP subgroup. STUDY DESIGN: Monocentric, cross-sectional study. PATIENT SAMPLE: Five hundred and sixty-five asymptomatic Chinese men and women between the ages of 18 and 80 years. OUTCOME MEASURES: Sagittal parameters including LL, lumbar lordosis minus thoracic kyphosis (LL-TK), PI, pelvic tilt (PT), pelvic incidence minus lumbar lordosis (PI-LL), sacral slope (SS), sacral slope divided by pelvic incidence (SS/PI), sagittal vertical axis (SVA), thoracic kyphosis (TK), and T1 (first thoracic vertebra) pelvic angle (TPA) were measured on whole spine radiographs obtained with participants in standing and sitting positions. METHODS: All participants underwent radiography in the standing position; 235 of them underwent additional radiography in the sitting position to allow measurement of sagittal parameters. The participants with pelvic anteversion were placed in an AP (anteverted pelvis) group. Sagittal parameters were compared between the AP group and the non-AP group, and predictive formulas for LL based on PI were created in both groups. In addition, changes in sagittal parameters from standing to sitting were compared in the AP group and a PI-matched control group. RESULTS: Of the 565 participants, 171 (30.3%) had pelvic anteversion. In comparison with the non-AP group, the AP group presented with larger LL, a larger SS, and a smaller PT, with relatively small PI. The predictive formulas for LL were LL=0.60° × PI+21.60° (R2=0.268; p<.001) in the whole cohort, LL=0. 83×PI+18.75° (R2=0.427; p<.001) in AP group, and LL=0.79°×PI+9.66° (R2=0.451; p<.001) in the non-AP group. In moving from standing to sitting, the AP group presented with a larger decrease in SS and LL compared with the control group, indicating different patterns of spinopelvic motion. CONCLUSIONS: In the cohort examined, 30.3% present with pelvic anteversion. Those with AP present with unique characteristics of spinopelvic alignment. In moving from standing to sitting, they exhibit different patterns of spinopelvic motion. We found that identifying the degree of anteversion in each person improves the accuracy of linear models for predicting the degree of LL, which in turn can make plans for spine surgery more accurate.

Relationship between the postoperative variations of paraspinal muscles and adjacent-segment degeneration in patients with degenerative lumbar spinal stenosis after posterior instrumented lumbar fusion.

OBJECTIVE: This study aimed to quantify pre- and postoperative paraspinal muscular variation following posterior lumbar interbody fusion (PLIF) in patients with degenerative lumbar spinal stenosis (DLSS) and measure the association of this variation with adjacent-segment degeneration (ASD). METHODS: Data from 149 patients who underwent L4-S1 PLIF for DLSS were collected. Patients were divided into radiologically confirmed ASD and control groups according to follow-up radiological findings. MRI was performed before surgery and at the last follow-up. Muscular parameters including the relative cross-sectional area (rCSA), relative functional cross-sectional area (rFCSA), relative total cross-sectional area (rTCSA), and fatty infiltration (FI) of the multifidus (MF), erector spinae (ES), and psoas major (PM) muscles were measured on preoperative and follow-up L2-S1 MR images. Logistic regression was used to investigate risk factors for ASD. RESULTS: The rate of radiological ASD was 42.3% at the final follow-up (mean 25.71 ± 8.35 months). At surgical levels, the rFCSA and rTCSA of the MF and ES muscles decreased. The FI of the MF from L2-3 to L5-S1 and ES muscles at L5-S1 significantly increased after surgery, while the rFCSA and rTCSA of the PM muscle increased and its FI decreased. At adjacent levels, the rFCSA and rTCSA of the MF muscle and rTCSA of the ES muscle decreased and the FI of the MF muscle increased postoperatively (p < 0.05), but the rFCSA and rTCSA of the PM muscle increased and its FI decreased (p < 0.05). The FIs of the MF, ES, and PM muscles at adjacent levels significantly differed between the ASD and control groups. Logistic regression analysis indicated that higher BMI (p = 0.002) and FI of the PM muscle at adjacent levels (p = 0.025) were significant risk factors for ASD. CONCLUSIONS: The functional area decreased in the MF and ES muscles and increased in the PM muscle after L4-S1 PLIF. A compensatory postoperative decrease in FI of the PM muscle at the adjacent level was a protective factor for ASD in DLSS patients after PLIF.

Association between the upper instrumented vertebra screw angles and proximal junctional complications in patients with de novo degenerative lumbar scoliosis.

OBJECTIVE: The aim of this study was to investigate the impact of upper instrumented vertebra (UIV) screw angles on proximal junctional complications in patients with de novo degenerative lumbar scoliosis (DNDLS). METHODS: A total of 120 patients with DNDLS who underwent posterior long-segment instrumentation and fusion were included. Patients were divided into a proximal junctional kyphosis/failure (PJK/PJF) group and a non-PJK/PJF group. Radiographic parameters were measured, including UIV screw angle, UIV slope, UIV screw slope, fixed segmental angle (FSA), and spinopelvic parameters. Clinical and radiographic data were compared between the two groups. Multivariate logistic regression was used to analyze the independent risk factors of PJK/PJF. Receiver operating characteristic (ROC) curve analysis was used to determine the threshold value to predict PJK/PJF. RESULTS: Thirty-six patients (30.0%) developed PJK or PJF during follow-up. Patients in the PJK/PJF group had a larger postoperative UIV screw angle, a larger postoperative UIV screw slope, and a larger postoperative PJA. A significant increase was observed in UIV screw angle from immediately postoperative assessment to the final follow-up in two groups (p < 0.001). Multivariate logistic analysis indicated that a larger positive postoperative UIV screw angle was an independent risk factor for PJK/PJF (OR 1.546, 95% CI 1.274-1.877). ROC curve analysis indicated that a UIV screw angle ≥ 1° is more likely to develop PJK/PJF. Compared with group A patients (UIV screw angle < 1°), group B patients (UIV screw angle ≥ 1°) had a higher incidence of PJK, PJF, UIV screw loosening, and worse functional scores at the final follow-up. CONCLUSIONS: Avoiding insertion of cranially directed UIV pedicle screws may help prevent the development of PJK and PJF in patients with DNDLS.

Role of the Paraspinal Muscles in the Sagittal Imbalance Cascade: The Effects of Their Endurance and of Their Morphology on Sagittal Spinopelvic Alignment.

BACKGROUND: The role of paraspinal muscle degeneration in the cascade of sagittal imbalance is still unclear. This study aimed to compare paraspinal muscle degeneration in the 4 stages of sagittal imbalance: sagittal balance (SB), compensated sagittal balance (CSB), decompensated sagittal imbalance (DSI), and sagittal imbalance with failure of pelvic compensation (SI-FPC). In addition, it aimed to compare the effects paraspinal muscle endurance and morphology on sagittal spinopelvic alignment in patients with lumbar spinal stenosis. METHODS: A cross-sectional study of 219 patients hospitalized with lumbar spinal stenosis was performed. The isometric paraspinal extensor endurance test and evaluation of atrophy and fat infiltration of the paraspinal extensor muscles and psoas major on magnetic resonance imaging were performed at baseline. Spinopelvic parameters including lumbar lordosis, pelvic tilt, sacral slope, pelvic incidence, and the sagittal vertical axis were measured. RESULTS: The patients with lumbar spinal stenosis were divided into 67 with SB, 85 with CSB, 49 with DSI, and 17 with SI-FPC. There were significant differences in paraspinal muscle endurance and morphology among the 4 groups. Furthermore, the SI-FPC group had poorer paraspinal muscle endurance than either the SB or the CSB group. In multiple linear regression analysis, paraspinal muscle endurance and the relative functional cross-sectional area of the paraspinal extensor muscles were the independent predictors of the sagittal vertical axis, and the relative functional cross-sectional area of the psoas major was the independent predictor of relative pelvic version. CONCLUSIONS: This study indicated that paraspinal muscle degeneration is not only an initiating factor in pelvic retroversion but also a risk factor for progression from a compensated to a decompensated stage. Specifically, the impairment of muscle endurance in the CSB stage may be the reason why patients experience failure of pelvic compensation. In addition, paraspinal muscle endurance and muscle morphology (relative functional cross-sectional area of the paraspinal extensor muscles and psoas major) had different clinical consequences. LEVEL OF EVIDENCE: Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

The Role of Thoracic Tilt in Identifying Thoracic Compensation and Predicting Proximal Junctional Kyphosis in Degenerative Lumbar Scoliosis.

STUDY DESIGN: A retrospective cohort study of consecutive patients. OBJECTIVE: To investigate the clinical value of thoracic tilt (TT) in characterizing thoracic compensation and predicting proximal junctional kyphosis (PJK) in degenerative lumbar scoliosis (DLS). SUMMARY OF BACKGROUND DATA: Thoracic compensation has been shown to be associated with the development of PJK, while thoracic shape and morphology in patients with DLS remain understudied. METHODS: Patients with DLS who underwent long-segment fusion were divided into a PJK group and a non-PJK group. Asymptomatic elderly volunteers were recruited as healthy controls. Thoracic parameters were measured in both cohorts, including the TT, T1-L1 pelvic angle (TLPA), T12 slope, thoracic kyphosis (TK, T4-T12), global thoracic kyphosis (GTK, T1-T12), and thoracolumbar kyphosis (TLK, T10-L2). Multivariate logistic regression was used to assess the association between TT and the development of PJK, adjusting for confounders. Multivariate linear regression was used to establish the predictive formula for TT. RESULTS: A total of 126 patients with DLS were enrolled, of which 37 (29.4%) developed PJK. Compared with 110 healthy controls, DLS patients had significantly greater TT, TLPA, T12 slope, and TLK as well as smaller TK and GTK (all P <0.001). Preoperatively, the PJK group showed significantly greater TT ( P =0.013), TLPA ( P <0.001), and TLK ( P =0.034) than the non-PJK group. No significant differences were found in TK and GTK before surgery. Postoperatively, the PJK group showed significantly greater TT ( P <0.001), TLPA ( P <0.001), TLK ( P <0.001), and proximal junctional angle ( P <0.001). Multivariate logistic regression analysis showed that greater postoperative TT was associated with the development of PJK. Multivariate linear regression analysis suggested that the regression formula was postoperative TT=0.675×T12slope+0.412×TK+0.158×TLK-4.808 ( R2 =0.643, P <0.001). CONCLUSIONS: The novel sagittal parameter TT can be used for the evaluation of thoracic compensation. Greater preoperative TT might represent a decompensated state of TK. Rebalancing the TT in a sagittal neutral position might help to prevent PJK in patients with DLS.

Endoscopic Laser Dissection Combined With Laparoscopic Pneumovesical Repair of Vesicovaginal Fistula: A Novel Technique and Case Report.

INTRODUCTION: We present a novel technique that combined endoscopic laser dissection and a transvesical laparoscopic approach for VVF repair in a transmasculine patient who received vaginal colpectomy. A literature review of VVF repair was also conducted. TECHNICAL CONSIDERATIONS: Surgical repair of VVF has been described extensively in the literature. Transvaginal and transabdominal laparoscopic approaches are currently the most common techniques for VVF management. However, for transmasculine patients, neither of these methods is ideal due to either a previous history of vaginal colpectomy or the position of the fistula. This case report demonstrates the feasibility of applying a combined endoscopic laser dissection and transvesical laparoscopic approach for VVF repair. CONCLUSION: The patient had an uneventful recovery, and the VVF healed over time. The advantages of this technique include a precise incision and dissection of the fistula orifice, clear exposure of the anatomic plane between the bladder and vaginal wall, and minimal injury to normal tissue. More cases are needed to demonstrate the effectiveness and complication rate of this technique in the future.

Does paraspinal muscle morphometry predict functional status and re-operation after lumbar spinal surgery? A systematic review and meta-analysis.

OBJECTIVES: Whether paraspinal muscle degeneration is related to poor clinical outcomes after lumbar surgery is still indistinct, which limits its clinical application. This study aimed to evaluate the predictive value of paraspinal muscle morphology on functional status and re-operation after lumbar spinal surgery. METHODS: A review of the literature was conducted using a total of 6917 articles identified from a search of PubMed, EMBASE, and Web of Science databases through September 2022. A full-text review of 140 studies was conducted based on criteria including an objective assessment of preoperative paraspinal muscle morphology including multifidus (MF), erector spinae (ES), and psoas major (PS) in addition to measuring its relationship to clinical outcomes including Oswestry disability index (ODI), pain and revision surgery. Meta-analysis was performed when required metrics could be calculated in ≥ three studies, otherwise vote counting model was a good alternative to show the effect direction of evidence. The standardized mean difference (SMD) and 95% confidence interval (CI) were calculated. RESULTS: A total of 10 studies were included in this review. Of them, five studies with required metrics were included in the meta-analysis. The meta-analysis suggested that higher preoperative fat infiltration (FI) of MF could predict higher postoperative ODI scores (SMD = 0.33, 95% CI 0.16-0.50, p = 0.0001). For postoperative pain, MF FI could also be an effective predictor for persistent low back pain after surgery (SMD = 0.17, 95% CI 0.02-0.31, p = 0.03). However, in the vote count model, limited evidence was presented for the prognostic effects of ES and PS on postoperative functional status and symptoms. In terms of revision surgery, there was conflicting evidence that FI of MF and ES could predict the incidence of revision surgery in the vote count model. CONCLUSION: The assessment of MF FI could be a viable method to stratify patients with lumbar surgery by the risk of severe functional disability and low back pain. KEY POINTS: • The fat infiltration of multifidus can predict postoperative functional status and low back pain after lumbar spinal surgery. • The preoperative evaluation of paraspinal muscle morphology is conducive for surgeons.

Retrospective analysis of 1470-/980-nm dual-wavelength laser en bloc resection versus transurethral resection of bladder tumor for primary non-muscle-invasive bladder cancer.

To compare the safety and efficacy of en bloc resection of non-muscle-invasive bladder cancer (NMIBC) using a 1470-/980-nm dual-wavelength laser (DwLRBT) compared to the gold standard, transurethral resection (TURBT). The study group included 251 patients with a confirmed diagnosis of NMIBC, 97 in the DwLRBT group and 154 in the TURBT group. Clinical characteristics, complications, and recurrence-free survival were compared between the two groups. There were no differences between the two groups with regard to age, sex, mean tumor size, mean tumor number, tumor location, risk, fever, and reoperation. Compared to TURBT, DwLRBT was associated with a shorter hospitalization time (mean±standard deviation: 5.81±1.48 days vs. 4.96±1.32, respectively, p=0.001), shorter catheterization time (4.98±1.47 vs. 4.20±1.48 days, respectively; p=0.035), and smaller volume of intraoperative bleeding (8.43±6.21 ml vs. 6.15±5.08, respectively; p=0.003). Recurrence-free survival (RFS) was better for DwLRBT than TURBT in the overall cohort (hazard ratio [HR], 0.4323; 95% confidence interval [CI], 0.2852-0.6554; p=0.0004) and for the following subgroups and tumor types: intermediate-risk (HR, 0.2654; 95%CI, 0.1020-0.6904; p=0.0245) and high-risk (HR, 0.4461; 95% CI, 0.2778-0.7162; p=0.0027) groups; and for pedunculate bladder tumors (HR, 0.4158; 95%CI, 0.2401-0.7202; p=0.0063), single bladder tumors (HR, 0.4136; 95%CI, 0.2376-0.7293; p=0.0072), and multiple bladder tumors (HR, 0.2727; 95%CI, 0.1408-0.5282; p=0.0014). DwLRBT is associated with better operative and postoperative outcomes, including, importantly, a longer RFS, compared to TURBT.

Which Global Sagittal Parameter Could Most Effectively Predict the Surgical Outcome for Patients With Adult Degenerative Scoliosis?

STUDY DESIGN: Retrospective study. OBJECTIVE: To evaluate the predictive effect of the 3 global sagittal parameters (Sagittal Vertical Axis [SVA], T1 Pelvic Angle [TPA], and relative TPA [rTPA]) in the surgical outcome of patients with adult degenerative scoliosis (ADS), then to define the optimum corrective goal based on the best of them. METHODS: 117 ADS patients were included in this study and followed-up for an average of 3 years. Functional evaluation and radiographs were assessed preoperatively and postoperatively. The predictive accuracy of SVA, TPA, and relative TPA was analyzed through receiver operating characteristic (ROC) curve. The cutoff value of TPA was obtained at the maximal Youden index from ROC curve. RESULTS: TPA most highly correlated with postoperative oswestry disability index (ODI). The best cutoff value of TPA was set at 19.3° (area under curve =0.701). TPA >19.3° was the highest risk factor in multivariate logistic regression analysis (OR = 7.124, P = 0.022). Patients with TPA <19.3° at 3 months after operation showed a better ODI than those with TPA >19.3°. Correcting TPA less than 19.3° for patients with preoperative TPA >19.3° attributed to a better health related quality of life (HRQOL) and sagittal balance at last follow-up. The formula "Postoperative TPA = 0.923 × PI - 0.241 × postoperative LL - 0.593 × postoperative SS - 2.471 (r = 0.914, r2 = 0.836, P < .001)" described the relation between SS, LL, PI, and TPA. CONCLUSION: TPA was a useful global parameter for the prediction of postoperative HRQOL for patients with ADS. Keeping TPA <19.3° could improve the postoperative HRQOL for ADS patients with preoperative TPA >19.3°, and TPA <19.3° could be an optimum correction target for patients with ADS.

Paraspinal Muscle Degeneration as an Independent Risk for Loss of Local Alignment in Degenerative Lumbar Scoliosis Patients After Corrective Surgery.

STUDY DESIGN: Retrospective study. OBJECTIVES: To investigate the effect of paraspinal muscle degeneration on the maintenance of local and global alignment among degenerative lumbar scoliosis (DLS) patients after corrective surgery. METHODS: 98 DLS patients with a mean follow-up period of 38.3 months after corrective surgery were included. The T1 pelvic angle (TPA), lumbar lordosis (LL), pelvic incidence were measured preoperatively, immediate postoperatively and at last follow-up. All patients were divided into LL maintenance group (n = 21) and LL loss group (n = 77). For patients with well-aligned correction (immediate postoperative TPA ≤ 20°, n = 73), they were divided into TPA maintenance group (last follow-up TPA ≤ 20°) and TPA loss group (last follow-up TPA > 20°). The relative gross cross-sectional area (rGCSA) and fat infiltration (FI) of multifidus (MF) and erector spinae (ES), and the relative functional CSA (rFCSA) of psoas major (PS) were measured at L3, L4 and L5 on preoperative magnetic resonance imaging. RESULTS: MF rGCSA were significantly smaller in LL loss group than in LL maintenance group. Both MF rGCSA and PS rFCSA were significantly smaller and MF FI was significantly higher in TPA loss group than in TPA maintenance group. Binary logistic regression revealed that the MF rGCSA was an independent factor of LL loss; Large immediate postoperative TPA was an independent risk factor of TPA loss, but not the parameters of paraspinal muscles. CONCLUSION: The effect of paraspinal muscles in lower lumbar segments might be mainly focused on the maintenance of local alignment rather than the global alignment.

Correlations between paraspinal extensor muscle endurance and clinical outcomes in preoperative LSS patients and clinical value of an endurance classification.

Background: Few study has investigated how paraspinal muscle endurance deteriorates in lumbar spinal stenosis (LSS) patients. In addition, little information is available on the relationship between clinical outcomes and the endurance of paraspinal muscles. Objective: To explore the correlation between paraspinal extensor muscle endurance, quality of life (QOL) and sagittal spinopelvic alignment. Besides, we attempted to propose a paraspinal extensor muscle endurance test (PEMET) classification for identifying the severity of clinical symptoms and sagittal imbalance in LSS patients. Methods: 171 hospitalized LSS patients and 100 healthy controls from the community were prospectively enrolled in this study. The paraspinal extensor endurance test was performed at baseline according to Ito test. The LSS patients were stratified into three groups based on the performance time of endurance test: grade I (<10s); grade II (10-60s); and grade III (>60s). Clinical measures of QOL included the visual analog scale scores (VAS) for back pain and leg pain and the Oswestry Disability Index (ODI). Sagittal alignment was analysed by standing posteroanterior and lateral whole spine X-ray in LSS patients. Results: The LSS group had a significantly shorter performance time of the endurance test than the control group. The paraspinal muscle endurance significantly correlated with VAS-back, VAS-leg, ODI, pelvic tilt, lumbar lordosis and sagittal vertical axis (SVA; all p < 0.05). In binary logistic regression, the performance time of the endurance test was an independent factor of both poor functional status (ODI >40; p = 0.005, OR = 0.985) and global sagittal imbalance (SVA >50 mm; p = 0.019, OR = 0.985). Based on PEMET classification, moving from the grade III group to the grade I group, there was progressive worsening in VAS-back and ODI (all adjusted p < 0.05). Moreover, the grade I group had significantly greater VAS- leg, less LL and greater SVA than the other two groups (all adjusted p < 0.05). Conclusion: Paraspinal muscle endurance was associated with QOL and sagittal spinopelvic alignment in LSS patients. A PEMET classification system has been constructed and has shown a correlation with QOL and sagittal imbalance. Translational potential statement: The PEMET classification system proposed in this study could be available for identifying the severity of clinical symptoms and sagittal imbalance during preoperative evaluation in LSS patients.

Reduction effect of oral pravastatin on the acute phase response to intravenous zoledronic acid: protocol for a real-world prospective, placebo-controlled trial.

INTRODUCTION: Zoledronic acid (ZA) has been used as a first-line treatment in patients with osteoporosis (OP) who receive an annual injection of 5 mg. However, side effects of bone pain and fever, known as the acute phase response (APR), have often been observed after clinical usage. A meta-analysis reported that the incidence of APR was 49.4% among patients with OP who received ZA for the first time and that 30% of patients with these adverse effects refused treatment in the following year. As a clinically used hypolipidaemic drug, statins can inhibit 3-hydroxy-3-methylglutaryl coenzyme A reductase to block the pathway upstream of farnesyl pyrophosphate synthase. This process can decrease the accumulation of isopentenyl pyrophosphate to prevent γδT-cell activation and inflammatory factor production, blocking APR occurrence. The aim of this study is to determine the reduction effect of oral pravastatin on APR and investigate the possible mechanisms underlying the effect in vivo. METHODS AND ANALYSIS: This will be a single-centre, placebo-controlled trial. Female participants will be allocated at a 1:1 ratio to receive either oral pravastatin or a placebo at 1-hour predose and 24 and 48 hours post-administration of ZA. The primary outcome will be the incidence of APR within 72 hours after ZA infusion. The secondary outcomes will include the occurrence time and severity of APR and the frequency and amount of acetaminophen usage within 72 hours after ZA infusion. This study will determine the preventive effect of oral pravastatin on APR in Chinese patients with OP, supporting the clinical application of ZA to alleviate concerns regarding safety and increase patient compliance. ETHICS AND DISSEMINATION: This study protocol has been registered with ClinicalTrials.gov. This study protocol was reviewed and approved by the Peking University Third Hospital Medical Science Research Ethics Committee. The results will be published in scientific peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT04719481.

Can fat infiltration in the multifidus muscle be a predictor of postoperative symptoms and complications in patients undergoing lumbar fusion for degenerative lumbar spinal stenosis? A case-control study.

PURPOSE: This study aimed to explore whether 25% as the cutoff value of fat infiltration (FI) in multifidus (MF) could be a predictor of clinical outcomes of lumbar spinal stenosis (LSS) patients. METHODS: A total of 461 patients undergoing posterior lumbar interbody fusion for LSS with 1-year follow-up were identified. After sex- and age-match, 160 pairs of patients were divided into a FI < 25% group and a FI ≥ 25% group according to FI of MF at L4 on preoperative magnetic resonance imaging. Patient-reported outcomes including the visual analog scale scores (VAS) for back pain and leg pain and the Oswestry disability index (ODI) scores were evaluated. Bone nonunion and screw loosening were evaluated by dynamic X-ray. RESULTS: After matching, there was no significant difference in age, sex, body mass index, fusion to S1, number of fusion levels, osteoporosis, spondylolisthesis, smoking and diabetes. FI ≥ 25% group had significantly higher VAS for back pain, VAS for leg pain and ODI than FI < 25% group at 1-year follow-up. However, there was no significant difference in the change of them from baseline to 1-year follow-up between the two groups. In light of complications, FI ≥ 25% group had a significantly higher rate of bone nonunion than FI < 25% group, whereas there was no significant difference of screw loosening rates between the two groups. CONCLUSION: MF FI might be a pragmatic cutoff value to predict bone nonunion in LSS patients, but it has little predictive value on screw loosening and postoperative improvement of symptoms.

Fat infiltration of paraspinal muscles as an independent risk for bone nonunion after posterior lumbar interbody fusion.

BACKGROUND: The prognosis value of paraspinal muscle degeneration on clinical outcomes has been revealed. However no study has investigated the effect of the fat infiltration (FI) of paraspinal muscles on bone nonunion after posterior lumbar interbody fusion (PLIF). METHODS: Three hundred fifty-one patients undergoing PLIF for lumbar spinal stenosis with 1-year follow-up were retrospectively identified. Patients were categorized into bone union (n = 301) and bone nonunion (n = 50) groups based on dynamic X-ray at 1-year follow-up. The relative total cross-sectional area (rTCSA) and FI of multifidus (MF) and erector spinae (ES), and the relative functional CSA (rFCSA) of psoas major (PS) were measured on preoperative magnetic resonance imaging. RESULTS: The nonunion group had a significantly higher MF FI and a higher ES FI and a smaller MF rTCSA than the union group (p = 0.001, 0.038, 0.026, respectively). Binary logistic regression revealed that MF FI (p = 0.029, odds ratio [OR] = 1.04), lumbosacral fusion (p = 0.026, OR = 2193) and length of fusion (p = 0.001, OR = 1.99) were independent factors of bone nonunion. In subgroup analysis, in one or two-level fusion group, the patients with nonunion had a higher MF FI and a higher ES FI than those of the patients with union (all p < 0.05). Similarly, in lumbosacral fusion group, the patients with nonunion had a higher MF FI and a higher ES FI than those of the patients with union (all p < 0.05). The logistic regressions showed that MF FI remained an independent factor of bone nonunion both in the patients with one or two-level fusion (p = 0.003, OR = 1.074) and in the patients with lumbosacral fusion (p = 0.006, OR = 1.073). CONCLUSIONS: Higher fatty degeneration was strongly associated with bone nonunion after PLIF. Surgeons should pay attention to the FI of paraspinal muscles when performing posterior surgery for patients, especially those who need short-segment fusion or to extend fusion to S1.

Paraspinal muscle characteristics on MRI in degenerative lumbar spine with normal bone density, osteopenia and osteoporosis: a case-control study.

BACKGROUND: To investigate the difference of paraspinal muscles in patients with normal bone density, osteopenia and osteoporosis. METHODS: Patients undergoing surgery for lumbar spinal stenosis were included. Thirty-eight patients with osteoporosis were matched to patients with osteopenia and patients with normal bone density in a 1:1 manner according to WHO criteria. Dual-energy X-ray absorptiometry (DXA) scans and lumbar CT were performed preoperatively to measure the BMD of lumbar, femur and hip and HU values of L1-L4 respectively. The relative total cross-sectional area (rTCSA) and fat infiltration (FI) of multifidus (MF) and erector spinae (ES), and the relative functional CSA (rFCSA) of psoas major (PS) were measured at L4-5 and L5-S level on preoperative MRI. RESULTS: Osteoporotic patients showed lower BMI, higher MF FI and higher ES FI when compared with normal bone density group (25.57 ± 3.71 vs 27.46 ± 3.11; 0.38 ± 0.1 vs 0.32 ± 0.08; 0.33 ± 0.1 vs 0.28 ± 0.08; all adjusted p < 0.05). Both the MF FI and ES FI were significantly correlated with lumbar T-score (r = - 0.223, p < 0.05; r = - 0.208, p < 0.05) and the averaged lumbar HU value (r = - 0.305, p < 0.01; r = - 0.239, p < 0.05). CONCLUSIONS: Osteoporosis and paraspinal muscle degeneration might interact with each other and coexist in patients with degenerative lumbar diseases. It is recommended that the paraspinal muscle degeneration should be considered simultaneously when finding a patient with low bone mass before surgery.

Prevalence of Internet Addiction and Its Relationship With Combinations of Physical Activity and Screen-Based Sedentary Behavior Among Adolescents in China.

BACKGROUND: Given the widespread prevalence and serious nature of Internet addiction (IA), this study aimed to estimate the prevalence of IA and assess the relationships between IA and combinations of physical activity (PA) and screen-based sedentary behavior (SB) among adolescents in China. METHODS: This cross-sectional study surveyed 31,954 adolescents in grades 7 to 12 in Beijing. IA, PA, screen-based SB, and other information were obtained from a self-administrated questionnaire. The chi-square test and mixed-effects logistic regression model were applied to estimate the relationship between IA and combinations of PA and screen-based SB. RESULTS: 6.2% of the surveyed adolescents reported IA and the prevalence of low PA/high screen-based SB, high PA/high screen-based SB, low PA/low screen-based SB, and high PA/low screen-based SB were 53.7%, 19.5%, 18.8%, and 8.0%, respectively. Mixed-effects logistic regression analysis showed that adolescents with low PA/high screen-based SB were 1.99 (95% confidence interval, 1.62-2.44, P < .001) times more likely to prefer IA than those with high PA/low screen-based SB. CONCLUSIONS: The prevalence of IA among Chinese adolescents is still high. Intervention programs like maintaining sufficient PA and reducing screen-based SB might contribute to reducing their IA.

Imaging Evaluation of Fat Infiltration in Paraspinal Muscles on MRI: A Systematic Review with a Focus on Methodology.

PURPOSE: Numerous studies have applied a variety of methods to assess paraspinal muscle degeneration. However, the methodological differences in imaging evaluation may lead to imprecise or inconsistent results. This article aimed to provide a pragmatic summary review of the current imaging modalities, measurement protocols, and imaging parameters in the evaluation of paraspinal muscle fat infiltration (FI) in MRI studies. METHODS: Web of Science, EMBASE, and PubMed were searched from January 2005 to March 2020 to identify studies that examined the FI of paraspinal muscles on MRI among patients with lumbar degenerative diseases. RESULTS: Intramyocellular lipids measured by magnetic resonance spectroscopy and FI measured by chemical-shift MRI were both correlated to low back pain and several degenerative lumbar diseases, whereas results on the relationship between FI and degenerative lumbar pathologies using conventional MRI were conflicting. Multi-segment measurement of FI at the lesion segment and adjacent segments could be a prognostic indicator for lumbar surgery. Most studies adopted the center of the intervertebral disc or endplate as the level of slice to evaluate the FI. Compared with visual semiquantitative assessment, quantitative parameters appeared to be precise for eliminating individual or modality differences. It has been demonstrated that fat CSA/total CSA (based on area) and muscle-fat index (based on signal intensity) as quantitative FI parameters are associated with multiple lumbar diseases and clinical outcomes after surgery. CONCLUSION: Having a good command of the methodology of paraspinal muscle FI on MRI was effective for diagnosis and prognosis in clinical practice.

The Effect of Paraspinal Muscle Degeneration on Distal Pedicle Screw Loosening Following Corrective Surgery for Degenerative Lumbar Scoliosis.

MINI: A total of 137 degenerative lumbar scoliosis patients were divided into two groups. In group A (six or more fused levels), mean rFCSA of erector spinae <0.71 was an independent risk factor of LIV screw loosening. In Group B (four or five fused levels), paraspinal muscle degeneration had no influence on LIV screw loosening. STUDY DESIGN: A retrospective study. OBJECTIVE: The aim of this study was to evaluate the effect of degeneration of paraspinal muscles, including psoas muscles, erector spinae muscles, and multifidus muscles on pedicle screw loosening at lower instrumented vertebra (LIV) following corrective surgery for degenerative lumbar scoliosis (DLS). SUMMARY OF BACKGROUND DATA: The relation between paraspinal muscles and pedicle screw loosening in DLS patients has not been reported. METHODS: A total of 137 DLS patients underwent corrective surgery with at least 1-year follow-up were included. The patients were divided into two groups: Group A (68 patients) had six or more fused levels and Group B (69 patients) had four or five fused levels. Muscular parameters, including relative cross-sectional area (rCSA) and muscle-fat index (MFI), were measured on preoperative magnetic resonance imaging. rCSA and MFI were measured for both gross muscle (G) and functional muscle (F) as rGCSA, rFCSA, GMFI, and FMFI. Muscle ratio was calculated as rFCSA/rGCSA. Pedicle screw loosening was assessed on spine radiographs or CT at final follow-up. Clinical and radiological screw loosening were classified according to clinical significance. RESULTS: LIV screw loosening occurred in 77 patients at final follow-up. In Group A, patients with LIV screw loosening had significantly higher FMFI of psoas muscles and lower rFCSA and rGCSA of erector spinae. Logistic regression revealed that mean rFCSA of erector spinae <0.71 (odds ratio = 5.0, 95% confidence interval = 1.5-16.4) was an independent risk factor of LIV screw loosening. Mean muscle ratio of erector spinae was significantly lower in patients with clinical screw loosening compared with radiological screw loosening in univariate analysis. In Group B, all muscular parameters showed no significant difference. CONCLUSION: Degeneration of paraspinal muscles, especially psoas muscles and erector spinae, affected LIV screw loosening in six or more level fusion in corrective surgery for DLS, whereas the four- or five-level fusion had no this influence. LEVEL OF EVIDENCE: 3.

A retrospective study. The aim of this study was to evaluate the effect of degeneration of paraspinal muscles, including psoas muscles, erector spinae muscles, and multifidus muscles on pedicle screw loosening at lower instrumented vertebra (LIV) following corrective surgery for degenerative lumbar scoliosis (DLS). The relation between paraspinal muscles and pedicle screw loosening in DLS patients has not been reported. A total of 137 DLS patients underwent corrective surgery with at least 1-year follow-up were included. The patients were divided into two groups: Group A (68 patients) had six or more fused levels and Group B (69 patients) had four or five fused levels. Muscular parameters, including relative cross-sectional area (rCSA) and muscle-fat index (MFI), were measured on preoperative magnetic resonance imaging. rCSA and MFI were measured for both gross muscle (G) and functional muscle (F) as rGCSA, rFCSA, GMFI, and FMFI. Muscle ratio was calculated as rFCSA/rGCSA. Pedicle screw loosening was assessed on spine radiographs or CT at final follow-up. Clinical and radiological screw loosening were classified according to clinical significance. LIV screw loosening occurred in 77 patients at final follow-up. In Group A, patients with LIV screw loosening had significantly higher FMFI of psoas muscles and lower rFCSA and rGCSA of erector spinae. Logistic regression revealed that mean rFCSA of erector spinae <0.71 (odds ratio = 5.0, 95% confidence interval = 1.5­16.4) was an independent risk factor of LIV screw loosening. Mean muscle ratio of erector spinae was significantly lower in patients with clinical screw loosening compared with radiological screw loosening in univariate analysis. In Group B, all muscular parameters showed no significant difference. Degeneration of paraspinal muscles, especially psoas muscles and erector spinae, affected LIV screw loosening in six or more level fusion in corrective surgery for DLS, whereas the four- or five-level fusion had no this influence. Level of Evidence: 3.