These results indicate that even in the very young neuromuscular patient, acceptable amounts of curve correction can be achieved and maintained with posterior-only unit rod instrumentation and fusion. The biomechanical stiffness of this construct seemed to be able to prevent the crankshaft phenomenon in the majority of those patients at risk.

Osteopetrosis is a group of rare sclerosing bone dysplasias. Orthopedic concerns in Osteopetrosis are principally related to the characteristic brittle "marble bone" in which fractures may be easily induced by relatively low-energy mechanisms. Femoral fractures are common in this patient population, and management presents a unique technical challenge. While osteopetrotic bone may be penetrated with a drill bit, the drill bit flutes are immediately filled with bone. This renders the drill ineffective, and generation of significant frictional heat can result in breakage of the drill. This case series describes the long-term management of nine osteopetrotic femoral fractures in three patients. The difficulties encountered in these cases prompted the development of a safe and efficacious technique for intramedullary fixation of these fractures.

Patients with osteopetrosis present unique surgical challenges during surgical correction of spinal deformities. The use of segmental sublaminar wires with 1/4-inch rods and crosslinks afforded stable fixation despite poor bone quality. Allograft bone combined with postoperative bracing resulted in a well-maintained correction and a solid fusion. Five year follow-up and continued radiographic evidence of stable fusion indicate that the presented approach can lead to a successful outcome in the osteopetrotic patient population.

No abstract

The ability of particulate bioactive glass to function as an effective bone graft material is directly related to its in vivo dissolution, ion release, and interparticle spacing (area associated with bone in-growth). A spherical shape represents an optimal geometry to control bioactive glass bone formation properties. Spherical particles were fabricated from 45S5 bioactive glass with unimodal (90-180, 180-355, and 355-500 μm) and bimodal size ranges (180-355/355-500 and 90-180/355-500 μm). Particles were formed into bone graft putties and compared to a commercially available product composed of irregular 45S5 bioactive glass particles (32-710 μm). Scanning electron microscopy characterization of spherical particles showed a relatively uniform sphere shape and smooth surfaces. Irregular particles were characterized by random shapes with flat surfaces and sharp edges. X-ray fluorescence and X-ray diffraction indicated that the spheroidization process maintained the properties of 45S5 bioactive glass. Cross-sectional micro-computed tomography imaging of the putty samples demonstrated that smaller spheres and irregular particles resulted denser packing patterns compared to the larger spheres.Isolated particles were immersed in simulated body fluid for 14 days to measure silicon ion release and bioactivity. Inductively coupled plasma spectroscopy showed faster ion release from smaller particles due to increased surface area. Bioactivity characterization of 14-day simulated body fluid exposed particle surfaces showed the presence of a hydroxycarbanoapatite mineral layer (characteristic of 45S5 bioactive glass) on all bioactive glass particles. Results demonstrated that spherical particles maintained the properties of the starting 45S5 bioactive glass, and that particle shape and size directly affected short-term glass dissolution, ion release, and interparticle spacing.