Adolescent idiopathic scoliosis (AIS) is a progressive deformity of the spine. Scoliotic curves progress until skeletal maturity leading, in rare cases, to a severe deformity. While the Cobb angle is a straightforward tool in initial curve magnitude measurement, assessing the risk of curve progression at the time of diagnosis may be more challenging. Epigenetic and genetic markers are potential prognostic tools to predict curve progression. The aim of this study is to review the available literature regarding the epigenetic and genetic factors associated with the risk of AIS curve progression. This review was carried out in accordance with Preferential Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The search was carried out in January 2022. Only peer-reviewed articles were considered for inclusion. Forty studies were included; fifteen genes were reported as having SNPs with significant association with progressive AIS, but none showed sufficient power to sustain clinical applications. In contrast, nine studies reporting epigenetic modifications showed promising results in terms of reliable markers. Prognostic testing for AIS has the potential to significantly modify disease management. Most recent evidence suggests epigenetics as a more promising field for the identification of factors associated with AIS progression, offering a rationale for further investigation in this field.

Low back pain is an extremely common condition with severe consequences. Among its potential specific causes, degenerative disc disease (DDD) is one of the most frequently observed. Mechanobiology is an emerging science studying the interplay between mechanical stimuli and the biological behavior of cells and tissues. The aim of the presented study is to review, with a systematic approach, the existing literature regarding the mechanobiology of the human intervertebral disc (IVD), define the main pathways involved in DDD and identify novel potential therapeutic targets. The review was carried out in accordance with the Preferential Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Studies were included if they described biological responses of human IVD cells under mechanical stimulation or alterations of mechanical properties of the IVD determined by different gene expression. Fifteen studies were included and showed promising results confirming the mechanobiology of the human IVD as a key element in DDD. The technical advances of the last decade have allowed us to increase our understanding of this topic, enabling us to identify possible therapeutic targets to treat and to prevent DDD. Further research and technological innovations will shed light on the interactions between the mechanics and biology of the human IVD.

Background: Adolescent idiopathic scoliosis (AIS) is a frequent disorder. Since patients with AIS are typically as active as age-matched controls and post-operative reduction in physical activity has detrimental effects on their well-being, return to sport (RTS) is an important perioperative concern. Aim of the present study is to review the literature concerning return to sport after spinal fusion for AIS. Methods: This work was carried out in accordance with Preferential Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The search was carried out in December 2020. Only peer-reviewed randomized controlled trials (RCTs), retrospective studies (RS), retrospective case series (RCS) and perspective cohort studies (PCS) were considered for inclusion. Results: Six studies were included; only one of them was prospective. All the authors reported a time to RTS ranging between 6 and 18 months. Between 28 and 36.6% of all patients changed sport, choosing lower impact activities, mostly due to loss of flexibility of the spine. No complications due to return to play were noted. Conclusion: According to current evidence, patients who received spinal arthrodesis for AIS can safely return to any sport, even those that require extreme levels of spinal and pelvic movements such as gymnastics and golf. As there is little evidence, however, of the spinal loading that occurs during such movements, there is a lack of scientific evidence-based recommendations or guidelines surgeons and other health care providers can follow. Prospective comparative studies are needed to investigate these biomechanical and clinical issues. Level of evidence: Level III.

Purpose: To retrospectively evaluate a cohort of athletically active patients who underwent surgery for adolescent idiopathic scoliosis (AIS), and to determine which clinical, surgical and anthropometric variables influenced their return to sport after surgery. Methods: 112 adolescents who underwent high-density posterior fusion for AIS by a single surgeon were analyzed for clinical, surgical and demographic predictors of return to presurgical physical activity levels. Data were retrospectively collected by charts and X-rays analysis and patients interviews. Results: Preoperative main curve Cobb was 64.4 ± 14.12° and obtained correction was 70.0 ± 12.5%. Included patients played many different sports (Table 4), most of all ballet (44/112, 39.2%), swimming (40/112, 35.7%) and gymnastics (32/112, 28.6%). At an average of 50.3 months follow-up, 76 (67.8%) patients returned to sports (RTS) at an equal or higher level than preoperatively. Younger age, lower Lenke curve type and lower main curve Cobb were significantly associated with RTS. As for RTS timing, patients who returned within the first 6 months were younger, with a higher Lenke and a less severe main curve, a more distal UIV and a more proximal LIV. No complications related to RTS were registered. Conclusion: In conclusion, patients with adolescent idiopathic scoliosis safely returned to physical activity after surgery. Younger age, higher Lenke type and lower main curve severity predicted a quicker return to sport. However, prospective studies are needed to confirm these findings.

Proximal Junctional Disease (PJD) and Surgical Site Infection (SSI) are among the most common complications following spine surgery. Their risk factors are not fully understood. Among them, sarcopenia and osteopenia have recently been attracting interest. The aim of this study is to evaluate their influence on mechanical or infective complications after lumbar spine fusion. Patients who underwent open posterior lumbar fusion were analyzed. Through preoperative MRI, central sarcopenia and osteopenia were measured with the Psoas Lumbar Vertebral Index (PLVI) and the M-Score, respectively. Patients were stratified by low vs. high PLVI and M-Score and then by postoperative complications. Multivariate analysis for independent risk factors was performed. A total of 392 patients (mean age 62.6 years, mean follow up 42.4 months) were included. Multivariate linear regression identified comorbidity Index (p = 0.006), and dural tear (p = 0.016) as independent risk factors for SSI, and age (p = 0.014) and diabetes (p = 0.43) for PJD. Low M-score and PLVI were not correlated to a higher complications rate. Age, comorbidity index, diabetes, dural tear and length of stay are independent risk factors for infection and/or proximal junctional disease in patients who undergo lumbar arthrodesis for degenerative disc disease, while central sarcopenia and osteopenia (as measured by PLVI and M-score) are not.

Surgical site infection (SSI) is a feared complication in spinal surgery, that leads to lower outcomes and increased healthcare costs. Among its risk factors, sarcopenia and osteopenia have recently attracted particular interest. The purpose of this article is to evaluate the influence of sarcopenia and osteopenia on the postoperative infection rate in patients treated with posterior fusion for degenerative diseases of the lumbar spine. This retrospective study included data from 308 patients. Charts were reviewed and central sarcopenia and osteopenia were evaluated through magnetic resonance images (MRI), measuring the psoas to lumbar vertebral index (PLVI) and the M score. Multivariate linear regression was performed to identify independent risk factors for infection. The postoperative SSI rate was 8.4%. Patients with low PLVI scores were not more likely to experience postoperative SSI (p = 0.68), while low M-score patients were at higher risk of developing SSI (p = 0.04). However, they did not generally show low PLVI values (p = 0.5) and were homogeneously distributed between low and high PLVI (p = 0.6). Multivariate analysis confirmed a low M score to be an independent risk factor for SSI (p = 0.01). Our results suggest that osteopenia could have significant impact on spinal surgery, and prospective studies are needed to better investigate its role.