The role of paraspinal muscle degeneration in coronal imbalance in patients with degenerative scoliosis

Quantitative analysis of paravertebral muscle asymmetry and its correlation with spinal deformity in patients with degenerative lumbar scoliosis: a retrospective case-control study

Background

The degeneration and functional decline of paravertebral muscles (PVMs) are reported to be closely linked to the incidence of degenerative lumbar scoliosis (DLS), a spinal deformity of the mature skeleton. However, the functional role and degeneration of PVMs and their relationship to the development of spinal deformities remain controversial. Therefore, the present study analyzed the morphological changes in the PVMs of patients with DLS, and explored the relationship between PVM degeneration and spinal osseous parameters.

Methods

In this retrospective case-control study, we evaluated the PVM parameters of patients with DLS (n=120) and compared them with patients free of DLS (control group, n=120). The cross-sectional area (CSA) and computed tomography (CT) values of the PVM at the lumbar vertebra 1-5 levels were measured. Further, the lumbar scoliosis Cobb, lumbar lordotic, and apical vertebral rotation angles were measured on CT and radiographs in the DLS group, and the relationship between PVM changes and these factors was analyzed.

Results

In the control group, the PVM CSA and CT values differed insignificantly between the bilateral sides at all levels (P>0.05). In the DLS group, the CSAs of the multifidus (MF) and erector spinae (ES) were larger on the convex side than the concave side (P>0.05), whereas that of the psoas major (PM) was smaller on the convex side than the concave side (P<0.05). The CT value of the PVM was lower on the convex side at all levels (P<0.05). The CSA and CT values on both sides of the patients were lower in the DLS group than the control group at all levels (P<0.05). Further, the degree of PVM asymmetry at the apical vertebral level was positively correlated with the lumbar scoliosis (P<0.01) and apical vertebral rotation angles (P<0.05), but negatively correlated with the lumbar lordotic angle (P<0.05).

Conclusions

Asymmetric degeneration of the PVM was observed bilaterally in DLS patients, and the degeneration was more pronounced on the concave side than the convex side. This asymmetrical degeneration was closely associated with the severity of lumbar scoliosis, vertebral rotation, and loss of lumbar lordosis, and a stronger correlation was observed with the MF and ES than with the PM.

The Role of Muscle Biomarkers in Adolescent Idiopathic Scoliosis

Adolescent idiopathic scoliosis (AIS) is the predominant orthopedic disorder in children, affecting 1-3% of the global population. Research in this field has tried to delineate the genetic factors behind scoliosis and its association with heredity since AIS is considered a polygenic disease and has different genetic and epigenetic factors. The current study conducted a narrative review of the literature, focusing on biomarkers in the pathophysiology of muscle in AIS patients. Articles were collected from Scopus, Pubmed, and Web of Science. The key screening parameters were scoliosis classification, sampling, and the biomarkers evaluated. This review emphasizes potential key mechanisms and molecular regulators in muscle tissue. While there has been limited focus on the proteins contributing to muscle changes in AIS, significant attention has been given to genomic studies of single-nucleotide polymorphisms, particularly in LBX1. Despite these efforts, the exact causes of AIS remain elusive, with several theories suggesting genetic and hormonal factors. This review identified critical protein biomarkers such as Gi-protein alpha subunits, fibrillin-1 and -2, and various differentially expressed proteins, which may be linked to muscle alterations in AIS. This field of research is still limited due to a lack of homogeneity in the distinction of patients by groups and curve severity. Although the pathophysiology of AIS is still unclear, molecular research is important to guide the treatment of AIS before achieving skeletal maturity, thus avoiding serious problems associated with posture changes and low quality of life. In the future, a more comprehensive synergy between orthopedic and molecular research might ameliorate the diagnosis and treatment of AIS patients.

Clinical Results of 10-mm Endoscopic Minimally Invasive Interlaminar Decompression in the Treatment of Lumbar Spinal Stenosis with Degenerative Lumbar Scoliosis and Simple Lumbar Spinal Stenosis

Purpose

The number of patients with lumbar spinal stenosis (LSS) with degenerative lumbar scoliosis (DLS) is gradually increasing as the population ages. The purpose of this study was to evaluate the clinical outcomes of 10-mm endoscopic minimally invasive interlaminar decompression for LSS with DLS and simple LSS.

Material and Methods

The clinical data of 175 consecutive elderly patients with LSS were retrospectively analyzed. They were divided into LSS group and LSS with DLS group based on whether they were accompanied by DLS. Patient demographics, perioperative indicators, and clinical outcomes were recorded. Lumbar spine stability was assessed by imaging data. Meanwhile, visual analog scale (VAS) scores, Oswestry Disability Index (ODI) scores, and the modified Macnab criteria were used to assess clinical outcomes.

Results

There were 129 patients in the LSS group and 46 patients in the LSS with DLS group. Both groups had similar VAS and ODI scores preoperatively, and both were significantly lower postoperatively (P < 0.05). However, patients combined with DLS showed higher VAS scores for low back pain at 3 months and 1 year postoperatively (P < 0.05). In addition, postoperative LL and PI-LL were significantly improved in both groups (P < 0.05). However, patients in LSS with DLS group showed higher PT, PI and PI-LL before and after surgery. According to the modified Macnab criteria, the excellent and good rates were 92.25% and 89.13% in the LSS group and LSS with DLS group at the last follow-up, respectively.

Conclusion

10-mm endoscopic minimally invasive interlaminar decompression for LSS with or without DLS has shown satisfactory clinical outcomes. However, patients with DLS may have higher residual low back pain after surgery.