Novel Insights into the Pathogenesis of Spinal Sarcopenia and Related Therapeutic Approaches: A Narrative Review

Comparison of paravertebral muscle thickness and fatty infiltration in patients with osteoporosis, osteopenia and normal bone mineral density: a single-blind retrospective controlled trial

PURPOSE

The objective of this study was to investigate the effects of paravertebral muscles and fatty infiltrations of the lumbar region in individuals with varying degrees of bone mineral density, including those with osteoporotic, osteopenic, and healthy control groups.

METHODS

This single-blind, retrospective, and controlled study included patients aged 50-90 years with lumbar magnetic resonance imaging (MRI) and dual-energy X-ray absorptiometry (DXA) measurements. The study sample was selected through a simple random sampling method. The patients were divided into three groups based on their T-values in DXA measurements. All patients were evaluated using MRI to measure the anteroposterior thickness of the multifidus, psoas, and erector spinae muscles. Additionally, the Goutallier classification was utilized to assess the degree of muscle fatty infiltration at the L3 vertebra level.

RESULTS

A total of 301 patients were included in the study. The mean age of the patients included in the study was 65.97 ± 8.15 years. A total of 274 patients (91%) were female. A notable reduction in the multifidus muscle was observed in both the osteoporotic and osteopenic groups when compared to the control group. A significant loss was observed in the erector spinae and psoas muscles in the osteoporotic group when compared to the osteopenic and control groups. Furthermore, a notable decline in erector spinae muscle mass was observed in the osteopenic group relative to the control group. The level of muscle fatty infiltration was found to be significantly higher in the osteoporotic group when compared to the control group.

CONCLUSION

In patients with osteoporosis, there is a notable reduction in lumbar paravertebral muscle mass and an increase in fatty infiltration when compared to the healthy control group. The loss of muscle mass is observable in the multifidus and erector spinae muscles during the osteopenic period, whereas it is observable in the psoas muscle during the osteoporotic period.

BMI-stratified cutoff values for spinal sarcopenia in Chinese adults based on CT measures: a multicentre study

BACKGROUND

Decreased size and mass of paraspinal muscles are associated with lower vertebral bone mineral density, more postoperative complications, increased mortality, and spinal sagittal imbalance. However, it is difficult to determine muscle loss in older adults with overweight and obesity. This study aimed to investigate the effects of body mass index (BMI) and central obesity on paraspinal muscle aging and to determine cutoff values for low paraspinal muscle mass/quality in Chinese community populations.

METHODS

In this nationwide cross-sectional study, abdominal CT scans and basic information were collected and analyzed from 4,305 community-dwelling adults from twelve representative cities in China between 2013 and 2017. Psoas and posterior paraspinal muscle index (PMI and PSMI) and density (PMD and PSMD) at the L3 level were measured using OsiriX software. Correlation analysis, multiple linear regression, and one-way ANOVA were performed for statistical analysis. Commonly used cutoff value calculations were applied to define low muscle index and density (Mean-2SD, 5th percentile in young people, and 20th percentile in older people) in the general population and individuals with different BMIs.

RESULTS

Correlation analysis showed that the paraspinal muscle index and density were primarily correlated with sex, BMI, and age. Multiple linear regression analysis indicated that the paraspinal muscle index (PSMI and PMI) was primarily influenced by sex (β=-0.391 and - 0.599, p < 0.001) and BMI (β = 0.442 and 0.371, p < 0.001), followed by age and waist circumference. In contrast, muscle density (PSMD and PMD) was mainly associated with sex (β=-0.405 and - 0.317, p < 0.001) and age (β=-0.409 and - 0.429, p < 0.001), with a slight influence from WC and BMI. Considering the significant effect of BMI on muscle mass, we calculated BMI-stratified cutoffs for PSMI (as 12.3/10.6, 15.0/11.7, and 15.2/11.9 cm2/m2 in normal, overweight, and obese men/women using M-2SD), PMI (as 3.8/2.9, 5.0/3.4, and 4.9/3.9 cm2/m2 in normal, overweight and obese men/women using M-2SD), and unstratified cutoffs for PSMD (as 36.3 and 31.1 HU in men and women) and PMD (as 40.1 and 36.9 HU in men and women).

CONCLUSIONS

This study found that sex and BMI were key determinants of paraspinal muscle mass, with BMI influencing paraspinal muscle number more than age. In contrast, muscle density was primarily influenced by sex and age. This study provided BMI-stratified and non-stratified cutoff values for low paraspinal muscle index and density, which aided in the identification of spinal sarcopenia in individuals with different BMIs.

The Effect of Spinopelvic Parameters on Anterior Bone Graft Subsidence in Surgical Treatment of Pyogenic Lumbar Spondylodiscitis

OBJECTIVE

To evaluate the effect of spinopelvic parameters on anterior bone graft subsidence and functional outcomes after anterior interbody fusion (AIF) and posterior instrumented fusion (PIF) in pyogenic spondylodiscitis (PS).

METHODS

Sixty-five patients who had received AIF+PIF for PS from July 2003 to December 2015 were enrolled. Based on the degree of bone graft subsidence, the patients were divided into groups A (minimal subsidence), B (moderate subsidence), and C (severe subsidence). Comparative analysis was performed evaluating patient demographics, spinopelvic parameters (kyphosis angle, involved segment's intervertebral height, pelvic incidence [PI], pelvic tilt, sacral slope, lumbar lordosis [LL], thoracolumbar kyphosis, and PI minus LL [PI-LL]), and clinical evaluation including Oswestry Disability Index score and visual analog scale (VAS) scores. The data were collected in a patient registry at perioperative, postoperative 3-month, and 2-year to assess clinical and radiological outcomes. Receiver operating characteristic analysis was applied for identification of cutoff points of LL and PI-LL in suggestion of clinical practice.

RESULTS

The 65 included patients had a mean follow-up period of 35.09 ± 38.30 months. Generalized estimating equation analysis showed that LL and PI-LL changes in group A were significantly different from those in group C but not in group B, revealing that preoperative LL and postoperative PI-LL are bone graft subsidence type indicators. By contrast, preoperative Oswestry Disability Index, postoperative 3-month VAS-back, preoperative VAS-leg, and postoperative 2-year VAS-leg scores were associated with bone graft subsidence type. Receiver operating characteristic analysis identified preoperative LL < 40.79° and postoperative PI-LL > 15° as significant predictive markers for severe bone graft subsidence, providing valuable thresholds for surgical risk evaluation.

CONCLUSIONS

Among spinopelvic parameters, preoperative LL and postoperative PI-LL are important parameters associated with bone graft subsidence severity in patients who had received AIF+PIF for PS.

How to prevent preoperative adjacent segment degeneration L5/S1 segment occuring postoperative adjacent segment disease? A retrospective study of risk factor analysis

OBJECTIVE

L5/S1 segment is one of the most common lumbar degenerative segments with high clinical failure rate. When the clinically responsible segment consists of one or more segments including L4/L5 segment, whether to merge the severely degraded L5/S1 segment together is a common problem plaguing clinicians. Therefore, the purpose of this study was to explore the risk factors for preoperative adjacent segment degeneration L5/S1 segment occuring Postoperative adjacent segment disease(ASDis), analyze the correlation between the high risk factors and the occurrence of adjacent segment disease, clarify the preventive measures and direction, and provide references for clinical selection of personalized treatment.

METHODS

The data of 119 patients with L5/S1 segment degeneration who underwent fixed to L4/5 posterior lumbar fusion surgery and were followed up in the orthopedic ward of Shandong Hospital of Traditional Chinese Medicine from January 2016 to January 2018 were retrospectively analyzed. According to the occurrence of ASDis at the last follow-up, all patients were divided into ASDis group (17 cases) and asymptomatic group (102 cases). The age, gender, BMI, bone mineral density and underlying diseases of the two groups were analyzed and compared. Perioperative time, intraoperative blood loss, incision length, number of surgical fusion segments, postoperative time on the ground, and hospital stay were recorded and compared. The improvement of VAS score and ODI index before and after operation were recorded and compared. X-ray and CT measurements were used to compare preoperative L5/S1 intervertebral space height, endplate Modic changes, gas in articular process, disc herniation calcification, sacral vertebrae lumbalization of patients, intraoperative L4/5 immediately corrected intervertebral space height, and sagittal position parameters of L5/S1 segment Segmental lordosis (SL), Pelvic incidence (PI), sacral slope (SS),lumbar lordosis (LL), pelvic tilt (PT), PI-LL and so on. Pfirmann grade, paravertebral muscle CSA, fat infiltration FI, paravertebral muscle rFCSA, psoas major CSA, and vertebral body area were measured and compared by MRI before surgery. The relative paravertebral cross-sectional area (rCSA), relative psoas major cross-sectional area (rCSA) and relative functional paravertebral cross-sectional area (rFCSA) were calculated. logistic regression analysis was used to determine the risk factors for preoperative adjacent segment degeneration L5/S1 segment occuring Postoperative ASDis, and the receiver operating characteristic (ROC) curve was described and the area under the curve was calculated.

RESULTS

All patients successfully completed the operation. Proportion of patients with osteoporosis combined with ASDis [yes/no, (9/8) vs. (21/81), P = 0.004], BMI [(27.55 ± 3.99) vs. (25.18 ± 3.83), P = 0.021], the number of fusion segments [(1.76 ± 0.75) vs. (1.28 ± 0.52), P = 0.020], the correction height of L4/5 intervertebral space [(2.71 ± 1.21) mm vs. (2.10 ± 1.10) mm, P = 0.037] were significantly higher than those in asymptomatic group. Bone mineral density T value in ASDis group [(-1.54 ± 1.68) g/cm2 vs. (-0.01 ± 2.02) g/cm2, P = 0.004] was significantly lower than that in asymptomatic group. There were no significant differences in operation time, incision length, intraoperative blood loss and walking time between the two groups (P > 0.05). Preoperative imaging: In ASDis group, paravertebral muscle CSA [(4478.37.3 ± 727.54) mm vs. (4989.47 ± 915.98) mm, P = 0.031], paravertebral muscle rCSA [(3.14 ± 0.82) vs. (3.87 ± 0.89), P = 0.002], paravertebral muscle rFCSA [(2.37 ± 0.68) vs. (2.96 ± 0.77), P = 0.003] were significantly lower than those in non-sedimentation group. Endplate Modic changes (I/II/III/ no, (3/5/4/7) vs (23/16/5/56), P = 0.048) and vertebral canal morphological classification (0/1/2 grade, (7/5/5) vs (69/25/8), P = 0.019) in ASDis group were significantly different from those in asymptomatic group. The proportion of patients with gas in L5/S1 segment in ASDis group [yes/no, (6/11) vs. (13/89), P = 0.019] was significantly higher than that in asymptomatic group. ASDis group of preoperative LL Angle [(34.10 + 13.83)° vs. (41.75 + 13.38) °, P = 0.032) and SL Angle [(15.83 + 5.07) vs. (22.77 + 4.68) °, P = 0.022],2 days after surgery LL Angle [(38.11 + 11.73) vs. (43.70 + 10.02) °, P = 0.038) and SL Angle [(15.75 + 3.92) vs. (19.82 + 5.46) °, P = 0.004), at the time of the last follow-up LL Angle [(37.19 + 11.99) vs. (43.70 + 11.34) °, P = 0.032) and SL Angle [(13.50 + 3.27) vs. (16.00 + 4.78) °, P = 0.041) were significantly less than the asymptomatic group. Postoperative imaging: There were no significant differences in the time of intervertebral bone fusion and the number of patients with failed internal fixation between the two groups (P > 0.05). At the last follow-up, VAS score [(3.24 ± 1.39) vs. (1.63 ± 0.84), P < 0.001] and ODI score [(21.00 ± 9.90) vs. (15.79 ± 4.44), P = 0.048] in ASDis group were significantly higher than those in asymptomatic group. Bivariate logistic regression showed that BMI value (OR = 1.715, P = 0.001) and number of surgically fused segments (OR = 4.245, P = 0.030) were risk factors for preoperative adjacent segment degeneration L5/S1 segment occuring Postoperative ASDis. The degree of spinal stenosis grade 0 (OR = 0.028, P = 0.003), the paraverteal muscle rFCSA (OR = 0.346, P = 0.036), and the Angle of Postoperative L5/S1 segment SL (OR = 0.746, P = 0.007) were protective factors for preoperative adjacent segment degeneration L5/S1 segment occuring Postoperative ASDis. Under ROC curve, the area of Postoperative L5/S1 segment SL Angle was 0.703, the area of paravertebral muscle rFCSA was 0.716, the area of BMI was 0.721, and the area of number of fusion segments was 0.518.

CONCLUSION

Excessive number of surgical fusion segments, spinal canal stenosis greater than grade 0, excessive BMI, too small Postoperative L5/S1 segment SL Angle, and too small paravertal muscle rFCSA are risk factors for preoperative adjacent segment degeneration L5/S1 segment occuring Postoperative ASDis. Prevention should be focused on the above aspects to reduce the incidence of L5/S1 segment ASDis.

Body Composition and Incident High-Intensity Back Pain and/or High Disability: A 10-Year Prospective Population-Based Male Cohort

BACKGROUND

Back pain poses a significant global burden, within which individuals with more severe symptoms consume higher healthcare expenses than those with lesser back pain. Whether measures of body composition predict high-intensity back pain and/or high-disability in population-based cohorts is unknown. This study aimed to examine the association between body composition at baseline and their change in the prior 5 years (between 2001-2005 and 2006-2010) and incident high-intensity back pain and/or high-disability in long-term follow-up, 10 years later (2016-2021) in a population-based cohort of men.

METHOD

This study examined men with no or low-intensity back pain and disability (Graded Chronic Pain Scale) at back pain study baseline (2006-2010) within the Geelong Osteoporosis Study. Those developing high-intensity pain and/or high disability at follow-up (2016-2021) were identified. Weight, body mass index (BMI), abdominal circumferences, fat mass and lean mass (dual energy X-ray absorptiometry) were assessed prebaseline (2001-2005) and at baseline. The association of body composition at baseline and change in body composition from prebaseline to baseline with incident high-intensity pain and/or high disability at follow-up were examined using multivariable logistic regression.

RESULT

Of 695 participants with no or low-intensity pain and disability at baseline, 441 (62.3%) completed follow-up with a mean age of 54.3 ± 14.1 years: 37 (8.3%) developed high-intensity pain and/or high-disability, 33 (7.5%) developed high-intensity pain and 14 (3.2%) high disability. No measures of body composition at baseline were associated with incident high-intensity pain and/or high disability at follow-up in the whole population. In subgroup analysis, among men aged over 60 years, but not younger, higher lean mass was associated with decreased likelihood of high-intensity pain and/or high-disability (odds ratio [OR] 0.86, 95% confidence interval [CI] 0.76, 0.97, interaction p < 0.001). In the whole population, examination of the relationship between change in measures of body composition between prebaseline and baseline, only a one unit increase in BMI, equivalent to 3.1-kg weight gain, was associated with increased incident high disability (OR 1.63, 95% CI 1.06, 2.51).

CONCLUSION

In a population-based sample, without severe back pain and disability, in older men aged ≥60 years, higher lean mass was protective of incident high-intensity pain and/or high disability. An increase in BMI, over 5 years, equivalent to 3.1-kg weight gain, was associated with incident back pain related high disability 10 years later. These results demonstrate another detrimental consequence of weight gain and highlight the importance of maintaining muscle mass in older men.

[Evaluation of sarcopenia and bioimpedance parameters related to muscle strength in the pre-operative consultation for spinal surgery]

Introduction

Introduction: sarcopenia is characterized by loss of muscle mass and function. Spinal disorders are a risk factor for muscle deterioration. In turn, sarcopenia is associated with adverse outcomes in the postoperative period of spinal surgery. Objectives: to evaluate sarcopenia and the relationship of muscle strength with bioimpedance parameters in the preoperative consultation. Material and methods: cross-sectional observational study. Muscle strength (dynamometry) and body composition (bioimpedance spectroscopy) were measured as part of the functional assessment of nutritional status. Sarcopenia was defined according to the European Working Group on Sarcopenia in Older People 2019 (EGWSOP2) and dynapenia/myopenia in the case of low strength or isolated muscularity. The relationship between the dynamometry values and the bioimpedance variables was summarized with the Spearman's coefficient. Results: twenty-two patients were included. The median (IQR) age was 60 years (43-65) and 72 % were women. The most frequent diagnosis and surgical procedure was spondylolisthesis (45 %) and posterior fixation (50 %). The mean body mass index (BMI) was 28.3 (± 4.59) kg/m2. The presence of sarcopenia, dynapenia and myopenia was 18.2 %, 13.6 % and 22.7 %, respectively. Dynamometry was correlated with lean tissue index: 0.61 (p 0.002); body cell mass: 0.68 (p 0.000); appendicular skeletal muscle: 0.49 (p 0.021); phase angle: 0.46 (p 0.031); and resistance index 200/5 kHz: -0.47 (p 0.028). Conclusion: muscle strength is correlated with bioimpedance parameters. Sarcopenia, dynapenia and myopenia are frequent and objectifiable in the preoperative spinal surgery consultation.

Gut-spine axis: a possible correlation between gut microbiota and spinal degenerative diseases

As society ages, the number of patients with spinal degenerative diseases (SDD) is increasing, posing a major socioeconomic problem for patients and their families. SDD refers to a generic term for degenerative diseases of spinal structures, including osteoporosis (bone), facet osteoarthritis (joint), intervertebral disk degeneration (disk), lumbar spinal canal stenosis (yellow ligament), and spinal sarcopenia (muscle). We propose the term "gut-spine axis" for the first time, given the influence of gut microbiota (GM) on the metabolic, immune, and endocrine environment in hosts through various potential mechanisms. A close cross-talk is noted between the aforementioned spinal components and degenerative diseases. This review outlines the nature and role of GM, highlighting GM abnormalities associated with the degeneration of spinal components. It also summarizes the evidence linking GM to various SDD. The gut-spine axis perspective can provide novel insights into the pathogenesis and treatment of SDD.

Significance of paraspinal muscle quality in risk between single and multiple osteoporotic vertebral fractures

PURPOSE

To compare paraspinal muscle quality between patients with single and multiple osteoporotic vertebral fractures (OVFs) and evaluate the role of the paraspinal muscles in OVFs.

METHODS

A total of 262 consecutive patients with OVFs were retrospectively analyzed in two groups: those with single OVF (n = 173) and those with multiple OVFs (n = 89). The cross-sectional area (CSA) and fatty degeneration of the paraspinal muscles were calculated from axial T2-weighted magnetic resonance imaging at the level of the L4 upper endplate by manual tracing in ImageJ software. Pearson's correlation analysis was performed to analyze correlations of paraspinal muscle quality to multiple OVFs.

RESULTS

FD in all the paraspinal muscles was significantly higher in the multiple OVF group than the single OVF group (all p < 0.005). The functional CSA (fCSA) of the paraspinal muscles was significantly lower in the multiple OVF group than the single OVF group (all Ps < 0.001), except for the erector spine (p = 0.304). The Pearson's correlation analysis showed significant positive inter-correlations for the fCSAs of all the paraspinal muscles and the occurrence of multiple OVFs.

CONCLUSIONS

The pure muscle volumes of the multifidus, psoas major, and quadratus lumborum were lower in patients with multiple OVFs than in those with a single OVF. Furthermore, the inter-correlation among all the paraspinal muscles indicate that the muscle-bone crosstalk profoundly existed in vertebral fracture cascade. Therefore, special attention to paraspinal muscle quality is needed to prevent progression to multiple OVFs.

Low paraspinal lean muscle mass is an independent predictor of adjacent vertebral compression fractures after percutaneous kyphoplasty: A propensity score–matched case-control study

Background

To investigate the relationship between paraspinal lean muscle mass and adjacent vertebral compression fracture (AVCF) after percutaneous kyphoplasty (PKP) for osteoporotic vertebral compression fracture (OVCF).

Methods

The data of 272 patients who underwent two consecutive single-level PKP in our hospital from January 2017 to December 2019 were collected. 42 patients who met the inclusion and exclusion criteria were selected as AVCF group, and 42 propensity score-matched patients were selected as control group. There were 10 males and 32 females in each group; the ages were 75.55 ± 5.76 years and 75.60 ± 5.87 years, respectively. All patients underwent preoperative lumbar MRI. The total cross-sectional area (CSA), functional cross-sectional area (FCSA), cross-sectional area of vertebra index (CSA-VI), functional cross-sectional area of vertebra index (FCSA-VI) of the multifidus (MF), erector spinae (ES), psoas (PS), and paravertebral muscles (PVM) were measured. Other related parameters included preoperative bone mineral density (BMD), kyphotic angle (KA), anterior-to-posterior body height ratio (AP ratio), vertebral height restoration, and cement leakage into the disc. Logistic regression analysis was performed to find independent risk factors for AVCF using the parameters that were statistically significant in univariate analysis.

Results

At L3 and L4 levels, the mean CSA, FCSA, and FCSA-VI of MF, ES, PVM and PS were significantly lower in the AVCF group. DeLong test indicated that the AUC of ES (0.806 vs. 0.900) and PVM (0.861 vs. 0.941) of FCSA-VI at L4 level were significantly greater than L3 level. In the AVCF group, patients had a significantly lower BMD (93.55 ± 14.99 HU vs. 106.31 ± 10.95 HU), a greater preoperative KA (16.02° ± 17.36° vs. 12.87° ± 6.58°), and a greater vertebral height restoration rate (20.4% ± 8.1% vs. 16.4% ± 10.0%, p = 0.026). Logistic regression analysis showed that PVM with lower FCSA-VI at L4 level (OR 0.830; 95% CI 0.760–0.906) and lower BMD (OR 0.928; 95% CI 0.891–0.966) were independent risk factors for AVCF after PKP.

Conclusions

Low paraspinal lean muscle mass is an independent risk factor for AVCF after PKP. Surgeons should pay attention to evaluate the status of paraspinal muscle preoperatively. Postoperative reasonable nutrition, standardized anti-osteoporosis treatment, and back muscle exercise could reduce the incidence of AVCF.

Major dietary patterns in relation to chronic low back pain; a cross-sectional study from RaNCD cohort

Background

Chronic low back pain (LBP) is the most common musculoskeletal pain that affects a person’s daily activities. This present study aimed at evaluating the relationship between major dietary pattern and Chronic LBP.

Methods

This cross-sectional analysis was examined 7686 Kurdish adults. The RaNCD cohort study physician diagnosed chronic LBP. Dietary patterns were derived using principal component analysis. The three identified dietary patterns derived were named: 1) the vegetarian diet included vegetables, whole grain, legumes, nuts, olive, vegetable oil, fruits, and fruit juice; 2) high protein diet related to higher adherence to red and white meat, legumes, nuts, and egg; and 3) energy-dense diet characterized with higher intake of salt, sweet, dessert, hydrogenated fat, soft drink, refined grain, tea, and coffee. Dietary pattern scores were divided into tertiles. Binary logistic regression in crude, adjusted odds ratios (OR) and 95% confidence intervals (CI) were used to determine this association.

Results

Twenty-two per cent of participants had chronic LBP. Higher adherence to high protein dietary pattern was inversely associated with chronic LBP in crude (OR: 0.79, 95% CI: 0.69–0.9) and adjusted model (for age, sex, smoking, drinking, diabetes, physical activity, body mass index, and waist circumference) (OR: 0.84, 95% CI: 0.72–0.97). In addition, after controlling for the mentioned potential confounders, participants in the highest category of energy dense diet were positively associated with chronic LBP compared with those in the lowest category (OR: 1.13, 95% CI: 1.01–1.32).

Conclusions

Higher adherence to the high protein diet was inversely related to chronic LBP prevalence. In addition, we found that following energy dense diet was positively associated with chronic LBP.

Posterior minimally invasive scoliosis surgery versus the standard posterior approach for the management of adolescent idiopathic scoliosis: an updated meta-analysis

Background

Surgical management of adolescent idiopathic scoliosis (AIS) can be performed using standard posterior spinal fusion (PSF) or with a posterior minimally invasive approach. Minimally invasive scoliosis surgery (MISS) has several theoretical advantages, such as less tissue dissection, less blood loss, and earlier recovery. However, the difference in safety and effectiveness between MISS and PSF still needs to be clarified. This updated meta-analysis aimed to compare the outcomes of MISS and standard PSF for the management of AIS.

Methods

A comprehensive literature search of PubMed, EMBASE, MEDLINE, and Cochrane Library without time restriction was performed to identify relevant studies. MISS and PSF were compared in terms of radiographic parameters, estimated blood loss (EBL), blood transfusion rate, operative time (ORT), length of hospital stay (LOS), overall Scoliosis Research Society-22 (SRS-22) score, postoperative pain, and complication rate.

Results

A total of seven studies comprising 767 patients (329 MISS and 438 PSF) with AIS were included. MISS and PSF yielded comparable deformity correction at the last follow-up. There were no significant differences in the overall SRS-22 scores or complication rates between the groups. Nevertheless, greater restoration of thoracic kyphosis (WMD, 2.98; 95% CI 0.58 to 5.37, P = 0.015), less EBL (WMD, −218.76; 95% CI −256.41 to −181.11, P < 0.001), a lower blood transfusion rate (RR, 0.31; 95% CI 0.20 to 0.48, P < 0.001), a shorter LOS (WMD, −1.48; 95% CI −2.48 to −0.48, P = 0.004), less postoperative pain (WMD, 0.57; 95% CI 0.16 to 0.98, P = 0.006), and a longer ORT (WMD, 84.85; 95% CI 33.30 to 136.40, P = 0.001) were observed in the MISS group.

Conclusion

Despite its inherent technical challenges, MISS is a feasible and effective alternative to standard PSF for AIS patients with moderate and flexible curves. MISS was associated with adequate deformity correction, better restoration of sagittal alignment, less EBL, fewer transfusions, shorter LOS, and better pain management compared to PSF. Further research is required to determine the detailed indications for the MISS procedure.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-02954-4.