A simple method for preconditioning radial forearm flaps in the case of an insufficient ulnar vascular supply: a retrospective clinical analysis.

Due to its versatile applicability, many reconstructive surgeons use the radial forearm flap (RFF) as the first choice for soft tissue replacement. Donor site limitations of the flap arise with an insufficient blood supply along the ulnar artery. This study presents a simple and safe method for RFF preconditioning by recruitment of the deep palmar arch via the ulnar artery. Fourteen patients scheduled for RFF surgery between 2013 and 2018 showed an insufficient vascular supply according to the Allen test, which was confirmed by digital subtraction angiography (DSA). These 14 patients underwent temporary ligature of one or both radial arteries with elastic vessel loops under local anaesthesia and continuous pulse oximetry. A control DSA was performed about 24hours later in 10 of the 14 patients. Recruitment of the blood supply along the enlarged ulnar artery or reanimated collaterals was confirmed in all 10 patients. No local complications such as ischemia of the hand were seen. All flaps could be harvested regularly and were used for different reconstructive purposes. This simple technique may help to overcome vascular limitations of the RFF via the rapid, efficient, and reliable recruitment of the biological vascular reserve. Within the limits of a case series, this procedure appears practicable and safe.

Osseointegration of biochemically modified implants in an osteoporosis rodent model.

The present study examined the impact of implant surface modifications on osseointegration in an osteoporotic rodent model. Sandblasted, acid-etched titanium implants were either used directly (control) or were further modified by surface conditioning with NaOH or by coating with one of the following active agents: collagen/chondroitin sulphate, simvastatin, or zoledronic acid. Control and modified implants were inserted into the proximal tibia of aged ovariectomised (OVX) osteoporotic rats (n = 32/group). In addition, aged oestrogen competent animals received either control or NaOH conditioned implants. Animals were sacrificed 2 and 4 weeks post-implantation. The excised tibiae were utilised for biomechanical and morphometric readouts (n = 8/group/readout). Biomechanical testing revealed at both time points dramatically reduced osseointegration in the tibia of oestrogen deprived osteoporotic animals compared to intact controls irrespective of NaOH exposure. Consistently, histomorphometric and microCT analyses demonstrated diminished bone-implant contact (BIC), peri-implant bone area (BA), bone volume/tissue volume (BV/TV) and bone-mineral density (BMD) in OVX animals. Surface coating with collagen/chondroitin sulphate had no detectable impact on osseointegration. Interestingly, statin coating resulted in a transient increase in BIC 2 weeks post-implantation; which, however, did not correspond to improvement of biomechanical readouts. Local exposure to zoledronic acid increased BIC, BA, BV/TV and BMD at 4 weeks. Yet this translated only into a non-significant improvement of biomechanical properties. In conclusion, this study presents a rodent model mimicking severely osteoporotic bone. Contrary to the other bioactive agents, locally released zoledronic acid had a positive impact on osseointegration albeit to a lesser extent than reported in less challenging models.