Spine Deformity

There is great controversy about the etiologic origin of adolescent idiopathic scoliosis. Multiple theories have been suggested, including metabolic aspects, endocrine dysfunction, neurological central abnormalities, genetic predisposition and epigenetic factors involved in the development of scoliosis. However, there has always been speculations based on human biomechanical behavior. In this article, we performed a literature review on the biomechanical traits of human posture, and the proposed theories that explain the special characteristics present in idiopathic scoliosis. The current theory on the etiopathogeneis of AIS suggests that dorsally directed shear loads acting on a preexisting axial plane rotation, in a posteriorly inclined sagittal plane of a growing patient, together with disc maturation, collagen quality at this phase of development and immaturity of proprioception, is the perfect scenario to spark rotational instability and create the three-dimensional deformity that defines idiopathic scoliosis. The unique spinal alignment of human bipedalism, gravity and muscle forces acting straight above the pelvis to preserve an upright balance, and the instability of the soft tissue in a period of growth development, is an appealing cocktail to try to explain the genesis of this condition in humans.

Early-onset scoliosis patients across all etiologies have similar clinical and radiographic outcomes after completion of traditional growing rod treatment.

Retrospective cross-sectional study. To analyze the referral pattern of patients with adolescent idiopathic scoliosis (AIS) in a tertiary hospital in a nationalized health care system without school screening and to compare curve magnitude on referral with results reported in the literature. In Denmark, school screening for AIS has not been in effect for more than two decades, and there is limited knowledge of curve magnitude and pattern of referral to specialized treatment in our country. Other studies, however, have assessed the effectiveness of school scoliosis screening. Our tertiary institution receives referrals for evaluation of AIS from general practitioners (GPs) and other hospitals or private specialists. A review was conducted on all patients diagnosed with AIS between 2010 and 2015. Data collection included age, gender, menarchal status, recommended treatment, and major curve Cobb angle for all patients aged 10–19 years referred for evaluation of AIS. Major curve magnitude was categorized as 10–19, 20–39, or ≥40 degrees, and the distribution of categories was compared to a screened population reported in the litterature. A total of 166 of 460 newly referred AIS patients were referred from GP. Mean age was 15 years (standard deviation = 2) and median Cobb angle was 35 degrees. Overall, 33% were initially recommended treatment with a brace. This group had a median curve size of 41 degrees, and 28% presented more than 1 year past menarche. We found a significantly larger curve magnitude at the time of referral in our GP cohort compared to a screened population (p <.001), and 22% versus 8% had a Cobb angle >40 degrees (p <.001). The present study confirms that in a health care system without school screening, patients with AIS referred for evaluation by GPs have larger curve sizes compared to systems with school screening. III

The three-rod technique, utilising a short apical concavity rod is an option to achieve controlled correction in severe scoliosis. We describe this technique, the complications encountered, and the long-term outcomes. All paediatric patients who had at least 2 years follow-up after undergoing corrective surgery for scoliosis ≥ 100° using 3 parallel rods were included. Radiographs were assessed to evaluate the correction and clinical records examined for any loss of correction, complications, revision procedures or neuromonitoring events. Twenty-five patients met the inclusion criteria. Four underwent prior anterior fusion to prevent crankshaft phenomenon. The mean angle of the deformity was 112.0° (range 100.3–137.1). Mean maximal kyphosis was 48.8° (range 11.4–78.8°) and mean curve flexibility 4.4% (range 0–37.0%). Intraoperative traction achieved an average of 70.4% (95% CI 56.6–84.1%). Nine patients (39%) showed a reduction in MEPs during definitive surgery. All returned to within 75% of baseline by the end of surgery. All patients had normal postoperative neurology. One patient underwent removal of hardware for late infection. The mean overall Cobb correction was 55.7° (95% CI 50.2–61.2°), equating to 50.2% (95% CI 44.9–55.4%) of the mean initial deformity. Thoracic kyphosis reduced by a mean of 18.2° (95% CI 12.8–23.6°). Our series suggests that three-rod constructs are able to safely and effectively achieve 50% correction of severe scoliosis.

Magnetically controlled growing rod (MCGR) is increasingly used in the treatment of early onset scoliosis. However, MRI requirement in patients with MCGR is of concern. This study investigated MRI safety of the MCGRs in an animal model and indicated that lower magnet MRI is safe in an animal model with MCGRs with no adverse effects regarding the MCGR or the animal.

To assess if the preservation of preoperative kyphosis within the cephalad two motion segments of instrumented posterior spinal fusions (PSF), for idiopathic scoliosis (IS), would be associated with lower frequency of proximal junctional kyphosis (PJK) at 2 years postoperatively. Previous studies on PJK in IS have reported conflicting findings; none has evaluated the relationship between segmental kyphosis within the cephalad instrumented construct and PJK. One hundred consecutive patients undergoing PSF for IS by a single surgeon with minimum 2-year follow-up were evaluated. Radiographic evaluation focused on sagittal alignment of the upper instrumented vertebrae (UIV), the 1 and 2 vertebrae cephalad (UIV + 1, UIV + 2) and caudal (UIV − 1, UIV − 2). This was measured between the inferior endplate of the UIV and the superior endplate of the UIV + 1 and UIV + 2 or between the superior endplate of the UIV and the inferior endplate of the UIV − 1 and UIV − 2. PJK was defined as present if the final UIV + 2 ≥ 10° and final UIV + 2—preop UIV + 2 ≥ 10°. There were 78 females and 22 males whose mean age was 14.6 (± 2.1) years at surgery; mean follow-up was 3.9 (2–9.3) years. The overall frequency of PJK was 25% (25/100) at final follow-up. Preoperative mean coronal curve measured 63° (40°–107°) with a mean 66% correction at final follow-up. UIV was T2 (n = 15), T3 (n = 47) or T4 (n = 38). More caudal UIVs were associated with PJK development (p = 0.04): T2 (13%), T3 (21%) and T4 (34%). Greater preoperative T5–T12 thoracic kyphosis and UIV − 2, and lower major curve apex (below T12) were more likely to develop PJK (p = 0.019, p = 0.004 and p = 0.007, respectively). Post-operatively, larger values for UIV − 1 (p ≤ 0.001) and UIV − 2 (p = 0.002) were associated with PJK at final follow-up. Longer fusion lengths (10–13 vs. 6–9 segments, p = 0.02) and the presence of thoracolumbar/lumbar structural curves (Lenke 3–6 vs. 1–2, p = 0.032) had higher rates of PJK (32% vs 10% and 37% vs 18%, respectively). Changes in UIV − 1 and UIV − 2 (preoperatively to immediately post-op) did not influence the development of PJK. At final follow-up, no patient required revision surgery for symptomatic proximal junctional kyphosis. In this study, changes in UIV − 1 and UIV − 2 at surgery were not related to PJK. Greater preoperative T5–T12 thoracic kyphosis and UIV − 2, lower major curve apex (T12 and below), and greater post-operative UIV − 1 and UIV − 2 were associated with higher frequencies of PJK. Higher UIV (T2 vs. T4) and LIV levels had a protective effect against PJK. Based on this study, the preservation of segmental kyphosis within the instrumented cephalad two levels of the PSF did not minimize the occurrence of radiographic PJK. Level IV.

Observational study. To evaluate self-image after in situ fusion for high-grade isthmic spondylolisthesis. Certain clinical findings such as short trunk or waistline skin folds are often seen in high-grade spondylolisthesis. Since treatment with spinal fusion in situ does not address appearance, self-image and also health-related quality of life might be negatively affected in the short-term as well as the long-term perspective. This observational study evaluated health-related quality of life outcome including self-image three decades after in situ fusion for high-grade isthmic spondylolisthesis in relation to healthy controls. Thirty-eight of 39 consecutive patients, fused in situ for high-grade isthmic spondylolisthesis at a young age, completed the Scoliosis Research Society (SRS)-22r questionnaire 28–41 years after surgery. The results were compared with the results of an age- and gender-matched control group. We found that the SRS-22r self-image domain scores were statistically significantly lower in patients than in controls whereas the pain and mental health scores were similar in patients and controls. Also, the SRS-22r function domain scores were statistically significantly lower in patients but the difference in means was small. We found no correlation between severity of slip and SRS-22r outcome. In situ fusion for high-grade isthmic spondylolisthesis is a safe treatment option in the long term from a function and pain perspective, but the results of our study suggest that self-image is negatively affected long into adult life. Level IV.