Adolescent idiopathic scoliosis (AIS) is an unexplained and common spinal deformity seen in otherwise healthy children. Its pathophysiology is poorly understood despite intensive investigation. Although genetic underpinnings are clear, replicated susceptibility loci that could provide insight into etiology have not been forthcoming. To address these issues, we performed genome-wide association studies (GWAS) of ∼327 000 single nucleotide polymorphisms (SNPs) in 419 AIS families. We found strongest evidence of association with chromosome 3p26.3 SNPs in the proximity of the CHL1 gene (P < 8 × 10−8 for rs1400180). We genotyped additional chromosome 3p26.3 SNPs and tested replication in two follow-up case–control cohorts, obtaining strongest results when all three cohorts were combined (rs10510181 odds ratio = 1.49, 95% confidence interval = 1.29–1.73, P = 2.58 × 10−8), but these were not confirmed in a separate GWAS. CHL1 is of interest, as it encodes an axon guidance protein related to Robo3. Mutations in the Robo3 protein cause horizontal gaze palsy with progressive scoliosis (HGPPS), a rare disease marked by severe scoliosis. Other top associations in our GWAS were with SNPs in the DSCAM gene encoding an axon guidance protein in the same structural class with Chl1 and Robo3. We additionally found AIS associations with loci in CNTNAP2, supporting a previous study linking this gene with AIS. Cntnap2 is also of functional interest, as it interacts directly with L1 and Robo class proteins and participates in axon pathfinding. Our results suggest the relevance of axon guidance pathways in AIS susceptibility, although these findings require further study, particularly given the apparent genetic heterogeneity in this disease.

We report the case of a 13-year-old boy with bilateral distal femoral unicameral bone cysts (UBCs) associated with acquired generalized lipodystrophy. As opposed to congenital generalized lipodystrophy, cystic bone lesions in acquired generalized lipodystrophy are rare. After radiographic and histologic confirmation of the UBCs, we performed percutaneous intramedullary decompression, curettage, and grafting. UBCs can be an important manifestation of acquired generalized lipodystrophy. Cystic bone lesions appear to be less common in acquired generalized lipodystrophy than in congenital generalized lipodystrophy, and intramedullary adipose tissue loss may be a predisposing factor for the development of bone lesions in patients with acquired generalized lipodystrophy. When evaluating a patient with lipodystrophy, doctors should recognize the clinical course may include the development of UBCs.

Aneurysmal bone cysts are benign active or aggressive bone tumors that commonly arise in the long bones, especially the femur, tibia, and humerus and the posterior elements of the spine. Aneurysmal bone cysts affect all age groups but are more common before skeletal maturity (first two decades of life). They usually involve the metaphysis or metadiaphyseal region of long bones. Although juxtaphyseal lesions abutting the growth plate and extending into the epiphysis have been described, there is no report of an aneurysmal bone cyst entirely and primarily located in the epiphysis. We report on a 3-year-old boy who presented with an entirely contained aneurysmal bone cyst to the proximal tibial epiphysis. We discuss the clinical presentation, diagnosis, including imaging and pathology, and treatment. A review of the pertinent literature also is presented.

Unicameral bone cysts are benign bone lesions commonly seen in pediatric patients. Several treatment methods have been described with variable results and high recurrence rates. We previously reported short-term success of a minimally invasive technique that includes combining percutaneous decompression and grafting with medical-grade calcium sulfate pellets. The purpose of this study was to review the additional long-term results with a minimum followup of 24 months (average, 37 months; range, 24–70 months). We identified 55 patients with an average age of 10.8 years (range, 1.3–18 years). Forty-one of 55 lesions occurred in the humerus and femur. Forty-four of 55 (80%) patients had a partial or complete response after initial surgery; of these, seven obtained a partial or complete response after a repeat surgery (cumulative healing rate, 94%). Two patients underwent a third surgery (cumulative healing rate, 98%). One underwent a third repeat surgery (cumulative healing rate, 100%). There were no major complications associated with the procedure. Two patients had a superficial infection that resolved with oral antibiotics. Although some patients required a repeat procedure, complete or partial response at a minimum 24 months’ followup was achieved in all patients.

Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Purpose

To evaluate the safety and efficacy of halo immobilization in children younger than 3 years.

Methods

All children less than 3 years of age who were placed in a halo-orthosis at a tertiary pediatric center were reviewed to determine the indications, safety, and efficacy of this method. Adequacy of immobilization and correct technique was established considering the chronology of maturation (skull and brain development). The functional outcome was analyzed.

Results

Ten patients (<3 years old) were identified from a total of 150 where halo ring/vest immobilization was used. There were six boys and four girls, with an average age of 2 years (range 10 months to 2 years and 10 months). The average time of immobilization in the halo-orthosis was 75 days (range 33–168 days), and the average follow-up time was 5 years and 2 months (range 1–12 years). There were two halo-related problems and four related to the index procedure. Halo-related problems included pin-site infection in one patient, and three pins loosening in another. There were four complications associated with the index procedure, all early in the series, including three cases of pseudarthrosis and one patient that had an insufficient decompression of basilar invagination. Two of the three failed fusions occurred at the occipito-cervical junction, which prompted us to develop new techniques for fusion at this level.

Conclusions

Halo-orthosis is a relatively safe and reliable device for immobilization of the upper cervical spine in children less than 3 years old. Understanding the developmental anatomy and a limited CT scan are helpful in pin placement. We recommend the use of a multiple pin construct, perpendicular insertion, and precise tightening with good pin-site care and frequent follow-up. The benefits seem to outweigh the risks in this population, considering the mechanical advantages of the halo-orthosis.