Scoliosis in Down's syndrome

Scoliosis in Adolescent Patients With Down Syndrome: Correlation Between Curve Magnitude and Functional Level

STUDY DESIGN

This is a retrospective, observational comparative study.

OBJECTIVE

The aim of this study is to determine whether a relationship exists between the functional level and spinal deformity in patients with Down syndrome (DS).

SUMMARY OF BACKGROUND DATA

Patients with DS have a higher incidence of scoliosis than the general population; however, it is unknown whether functional level influences the characteristics and severity of the deformity.

MATERIALS AND METHODS

Of 649 patients with DS included in a pediatric referral center database, we identified 59 with a diagnosis of scoliosis (59.32% female; mean age, 14.19±1.82 y); the 46 patients who met the inclusion criteria comprised the study cohort. According to their functional gait skills and gross motor skills, they were classified into 2 levels. Different coronal and sagittal parameters were measured using full-spine standing radiographs. The need for surgical treatment and history of thoracotomy were recorded as well. Finally, a multivariate association analysis was performed between radiologic parameters and functional level.

RESULTS

Twenty-two patients had a functional level consistent with level I and 24 with level II. Twelve curves were thoracic, 10 thoracolumbar, and 24 lumbar. A statistically significant relationship was found between functional level I and II and curve magnitude: 18.9 degrees (6.8) versus 36.9 degrees (20.3) ( P =0.001) with a cutoff point at 22.3 degrees (area under the curve=0.919, P <0.005, sensitivity=0.917 and specificity=0.818). The relationship between patients who required surgery and level II was also significant ( P =0.016). No relationship was found between functional level and coronal and sagittal balance, nor with other radiologic parameters or with curve location, or between the history of thoracotomy and thoracic curves.

CONCLUSIONS

DS adolescents with poorer functional level were associated with larger curves and greater risk for surgery. These findings may provide valuable guidance for the follow-up of scoliosis in patients with DS based on their functional level.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Loss of CSF-contacting neuron sensory function is associated with a hyper-kyphosis of the spine reminiscent of Scheuermann's disease

Scheuermann's disease, also referred to as Scheuermann's kyphosis, is the second most frequent spine deformity occurring in humans after adolescent idiopathic scoliosis (AIS), both with an unclear etiology. Recent genetic studies in zebrafish unraveled new mechanisms linked to AIS, highlighting the role of the Reissner fiber, an acellular polymer bathing in the cerebrospinal fluid (CSF) in close proximity with ciliated cells and mechanosensory neurons lining the central canal of the spinal cord (CSF-cNs). However, while the Reissner fiber and ciliary beating have been linked to AIS-like phenotypes in zebrafish, the relevance of the sensory functions of CSF-cNs for human spine disorders remains unknown. Here, we show that the thoracic hyper-kyphosis of the spine previously reported in adult pkd2l1 mutant zebrafish, in which the mechanosensory function of CSF-cNs is likely defective, is restricted to the sagittal plane and is not associated with vertebral malformations. By applying orthopedic criteria to analyze the amplitude of the curvature at the apex of the kyphosis, the curve pattern, the sagittal balance and sex bias, we demonstrate that pkd2l1 knock-outs develop a phenotype reminiscent of Scheuermann's disease. Altogether our work consolidates the benefit of combining genetics and analysis of spine deformities in zebrafish to model idiopathic spine disorders in humans.

Outcomes of Posterior Spinal Fusion in Pediatric Patients with Down Syndrome

BACKGROUND

Trisomy 21 or Down syndrome is associated with multiple orthopaedic manifestations. Although cervical instability is the most common spinal condition associated with Down syndrome, the prevalence of scoliosis has been estimated at 4.8% to 8.7%. Very few prior studies have documented the role of spinal fusion in this population, and all have included ≤10 patients.

METHODS

An institutional review board-approved multicenter retrospective analysis of patients with Down syndrome treated with spinal fusion between January 2009 and December 2019 was performed by cross-referencing Current Procedural Terminology (CPT) and International Classification of Diseases, Ninth and Tenth Revisions (ICD-9 and ICD-10) codes. Patients were followed for ≥2 years, with a mean follow-up of 3.77 years. Clinical and radiographic outcomes were collected, and complications were documented using the Clavien-Dindo-Sink (CDS) classification.

RESULTS

A total of 23 patients were included: 96% had ≥1 medical comorbidities, including 16 (70%) with congenital heart disease, of whom 88% had previous cardiac surgery, and 10 (44%) with thyroid disorders. All 23 patients underwent posterior spinal fusion. The mean estimated blood loss was 617 ± 459 mL, the mean length of the surgical procedure was 290 ± 92.7 minutes, and the mean length of hospital stay was 6.03 ± 2.91 days. The major Cobb angle measured 61.7° ± 17.6°, which corrected to 19.4° ± 14.8° (68.6% correction; p < 0.001), with well-maintained correction at 2 years of 22.0° ± 10.3° (64.3% correction; p = 0.158). Thirteen (57%) of 23 patients had a change in curve of >5°. There were no intraoperative complications; however, 12 patients (52%) sustained postoperative complications (e.g., need for reoperation, implant failure, and pulmonary complications), including 6 patients with CDS type 3 or 4 (e.g., wound dehiscence, late superficial abscess, pleural effusion, pseudarthrosis, and readmission for hypoxia). Four patients (17%) required a revision surgical procedure. One patient (4%) required an unplanned intensive care unit admission.

CONCLUSIONS

Although instrumented spinal fusion can effectively correct spinal deformity in these patients, complications are more frequent than in children with adolescent idiopathic scoliosis, with over half of patients sustaining a complication.

LEVEL OF EVIDENCE

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Late implant migration with neurologic compromise as a complication of scoliosis surgery

Late neurological deficit following scoliosis surgery is a rare event and any change in the patient's neurological status deserves immediate attention. We report on two clinical cases (at 2 and 6 years of follow-up) where two different types of proximal instrumentation resulted in lateral drift into the spinal canal causing cord compression with neurological deficit. Late neurological compromise in a posterior spinal-fusion setting deserves a prompt and complete spine investigative search for non-union, infection, or implant migration into the spinal canal.