Management of paediatric humeral shaft fractures and associated nerve palsy.

PURPOSE: The aim of this study is to review the management of all paediatric humerus diaphyseal fractures treated at a single institution over a 20-year period. METHODS: Retrospective review from between 1996 and 2016 identified 96 humerus shaft fractures in paediatric patients (0 to 17 years). After excluding those deceased from inciting trauma, pathological and perinatal fractures, 80 patients remained for analysis. Data collected included age, fracture type, displacement, nerve palsy, treatment, complications and time to union. Radiographs were reviewed at the time of injury and at latest follow-up. RESULTS: Of 80 paediatric humeral diaphyseal fractures, 65 (81%) were treated with immobilization. In all, 15 (19%) fractures were treated with surgical stabilization. Most common indications were fracture displacement, open fractures and to improve mobilization in patients with multiple injuries. Fractures were stabilized with a plate (eight), flexible nails (five), external fixation (one) and percutaneous pinning (one). The operative group, compared with the nonoperative group, was older, had more high-energy mechanisms, more open fractures and increased fracture displacement. All patients in the nonoperative and operative groups went on to union with minimal complications. A nerve palsy was present in five patients (6%)with three of the five involving the radial nerve (4%). All nerve palsies were observed and had full neurological recovery. CONCLUSION: Over a 20-year period nonoperative management of paediatric humerus shaft fractures was successful in the majority of patients. Operative stabilization, when rarely indicated, had a low complication rate and improved radiographic alignment. All nerve injuries fully recovered without surgical intervention. LEVEL OF EVIDENCE: IV.

Resection of multiple mediastinal paragangliomas with cardiopulmonary bypass.

The case of a patient who underwent simultaneous resection of two separate mediastinal paragangliomas is presented. The tumors were located in the aortopulmonary window and in the right atrioventricular groove. The patient had previously undergone resection of a glomus vagale tumor. The mediastinal lesions were removed with the aid of cardiopulmonary bypass, and the patient is doing well postoperatively.

Porous PLGA scaffolds for controlled release of naked and polyethyleneimine-complexed DNA.

The ability to precisely control delivery of single or multiple bioactive molecules is critical in tissue engineering, and controlled release of plasmid coding for growth factors and their regulators can give cell-regulated, short-term expression of these therapeutic biomolecules. In this work, porous poly(lactic-co-glycolic acid) (PLGA) scaffolds comprising acid-terminated chains of either low (LMW; 10 kDa) or high molecular weight (HMW; 30 kDa) were developed for controlled release of naked or polyethyleneimine (PEI)-complexed DNA. The compressive strength of blank HMW and LMW scaffolds was 6 and 2 MPa, respectively, while the strength of PEI:DNA-containing HMW and LMW scaffolds was 7 and 1 MPa, respectively. LMW scaffolds degraded more quickly than HMW scaffolds, with 80-100% and 15-30% mass loss at 30 days, respectively. Encapsulation of plasmid, particularly PEI-complexed DNA, only modestly affected degradation. Release profiles showed bi- or triphasic patterns, with early burst release of surface-associated DNA, slower diffusion-mediated release, and degradation-related release at later time points. Complexation with PEI tended to a slow release of plasmids, likely because of interaction with the carboxyl groups of PLGA. Culturing rat bone marrow cells on blank PLGA scaffolds in the presence of IGF-I resulted in growth and chondrogenic differentiation of these cells. Porous scaffolds made of PLGA with the appropriate selection of hydrophobicity and molecular weight will allow controlled delivery of naked and condensed plasmid DNA for different tissue engineering applications.

Development of an injectable two-phase drug delivery system for sequential release of antiresorptive and osteogenic drugs.

Unlike controlled release systems that deliver a single drug, dual or multidrug delivery systems with distinct release profiles are more likely to promote timely and effective tissue regeneration as they provide both temporally and concentration-dependent release of different molecules to mimic natural biological events. In this study, an injectable and biodegradable delivery system was developed to sequentially release an antiresorptive drug (clodronate) followed by an osteogenic agent (simvastatin) to treat bone disease. The injectable delivery system comprised simvastatin-loaded gelatin microspheres suspended in a viscous solution of carboxymethylcellulose (CMC) containing clodronate. Several factors (CMC concentration, glutaraldehyde concentration, simvastatin loading, and gelatin microsphere processing conditions) were investigated for their effects on drug release. Clodronate release was not affected by CMC concentration, with complete delivery within 12 hr, and simvastatin release could be modulated by cross-linking of the gelatin microspheres, loading, and washing conditions. Burst release of simvastatin was reduced from 70% to 6% in conjunction with sustained release for up to 3 weeks. The combined system showed early release of the antiresorptive clodronate sequentially followed by sustained delivery of the osteogenic simvastatin. This robust and flexible two-phase delivery system may prove useful for applications in which multiple drug delivery is desired.

Biomechanical efficacy of an internal fixator for treatment of distal radius fractures.

Despite the effectiveness of external fixation in the treatment of complex wrist fractures, the complication rate for this modality ranges from 20% to 62%. Common complications are related to the use of percutaneous metal pins and result in an average reoperation rate of 16%. In addition, external fixation is unable to prevent dorsal collapse of the radius or maintain the normal palmar tilt of the radiocarpal joint surface. This complication may predispose to posttraumatic wrist instability and arthritis. The problems with external fixation have prompted a search for a better treatment option. An internal fixator placed through limited incisions on the dorsal aspect of the radius and spanning the fracture site can, in theory, provide the benefits of external fixation without the associated morbidity. This study determined the biomechanical efficacy of internal fixators compared with external fixators using a standardized model for an unstable wrist fracture. Two commercially available metal plates were used as internal fixators. Biomechanical testing of the devices was done, and stiffness was determined. Results showed that the internal fixators were significantly stiffer than were the external fixators in axial loading. Failure in axial loading, specifically compression, is a consistent reason for loss of reduction in intraarticular distal radius fractures. The clinical implications of these results suggest that an internal fixator theoretically can prevent loss of reduction in the axial plane and maintain palmar tilt by acting as a rigid dorsal buttress. In addition, the use of an internal fixator potentially decreases the high morbidity associated with external fixation. Additional investigation into the clinical application of internal fixators for distal radius fractures is needed.