Initial Experience With Percutaneous IM Rodding of the Humeri in Children With Osteogenesis Imperfecta.

BACKGROUND: To report a single-center surgical experience treating humeral deformity and fractures in children with osteogenesis imperfecta (OI) using the Fassier-Duval (FD) intramedullary elongating rods. METHODS: A retrospective review was conducted between December 2005 and July 2013 of all OI patients who underwent FD rodding with a minimum of 1-year follow-up. All patients were also being concurrently treated with bisphosphonates. RESULTS: Eighteen patients underwent internal fixation on a total of 35 humeri: 7 males and 11 females with an average age of 49 months. Thirty-five procedures were performed using FD rodding, with 5 utilizing only the male portion. Thirty procedures were primary FD implantation and 5 were revisions. Twelve patients had type III OI and 6 patients type IV OI. Indications for surgery included recurrent fracture, severe bowing deformity, and pain. Osteotomy methods included closed osteoclasis, percutaneous, or open osteotomies. Two patients required transfusions during their hospital stay. At our determined endpoint, 23 humeri (65.7%) had acceptable results with a mean follow-up time of 43 months (SD=27) with no revision. The remaining 12 humeri (34.3%) necessitated revision with a mean time to revision of 35 months (SD=29). Reasons for revision included: migration resulting in pain and functional difficulty (8.6%), migration with bowing (8.6%), and hardware failure secondary to trauma (8.6%). In addition, 2 revisions were required for nonunion (5.7%) and 1 for malunion (2.9%). To our knowledge, all other osteotomies performed during surgery resulted in bony union. CONCLUSIONS: The use of the FD system for correction of humeral deformity demonstrates a reasonable option to improve comfort and function in children with recurrent fractures and deformity secondary to OI. The FD system allows for decreased revision rates and less morbid instrumentation. LEVEL OF EVIDENCE: Level IV-retrospective case series.

Low bone mineral density is a common feature of Zellweger spectrum disorders.

Patients with Zellweger Spectrum Disorders (ZSDs) have impaired peroxisome biogenesis and severe, multisystem disease. Although the neurologic symptoms of ZSD tend to be the most prominent, patients also have hepatic, renal and adrenal impairment. Little is known about bone health in patients with ZSD, particularly those with mild or moderate presentation. We investigated 13 ZSD patients who had strikingly abnormal bone mineral density for age. DXA scans showed mean lumbar and femoral neck Z-scores of -3.2. There were no major differences between ambulatory and nonambulatory patients, and no biochemical abnormalities consistent with rickets or vitamin D deficiency were seen. Cyclic bisphosphonate therapy in one ZSD patient was successfully used to increase in bone mineral density. Although the etiology of bone disease in this condition is unknown, we speculate that altered signaling through the PPARγ pathway or deficient plasmalogens in patients with ZSD disrupts osteogenesis, resulting in poor bone formation and poor mineralization. Further investigation into the pathogenic mechanisms of bone disease in ZSD and the role of peroxisomal metabolism in osteogenesis may yield insights into the pathology of bone disease and suggest novel treatment options.

Echocardiographic phenotype in osteogenesis imperfecta varies with disease severity.

BACKGROUND AND OBJECTIVES: Our purpose was to investigate cardiovascular abnormalities in children with osteogenesis imperfecta (OI). METHODS: Two hundred children (100 OI, 100 matched volunteers) were prospectively studied. Aortic and left ventricular (LV) measurements were performed using transthoracic echocardiography. Patients were typed according to modified phenotypical Sillence classification as published in the Nosology and Classification of Genetic Skeletal disorders: 2015 Revision. RESULTS: Patients (age 9.6±4.1 years, body surface area 1.08±0.47 m2) consisted of OI types: 1 (n=44), 3/4 (n=54), 4 (n=1) and 15 (n=1). The 95% CIs for Z-score of aortic annulus, sinus, sinotubular junction and ascending aorta for OI were 0.43 to 0.73, 0.56 to 0.94, 0.28 to 0.70 and 0.78 to 1.24, respectively. In type 1, sinus, sinotubular junction and ascending aorta diameters were 2.29 cm, 1.81 cm and 2.05 cm, respectively, which did not differ compared with controls. The LV dimensions were larger in type 1. In type 3/4, aortic dimensions were larger than controls at all levels: annulus (1.61 vs 1.50 cm, p<0.001), sinus (2.19 vs 2.05 cm, p=0.001), sinotubular junction (1.77 vs 1.64 cm, p<0.001) and ascending aorta (1.98 vs 1.82 cm, p<0.001), but LV dimensions were normal. CONCLUSIONS: Cardiovascular effects are identifiable in childhood even in mild forms of OI. Aortic dilation was the predominant finding, while valvular abnormalities were infrequent. Patients with more severe skeletal pathology (types 3/4) have more significant findings. Aortic and LV dilation in type 1 vs type 3/4 appears to differ based on the biochemical mechanism of disease.