Initial observations on using magnesium metal in peripheral nerve repair.

Biodegradable magnesium metal filaments placed inside biodegradable nerve conduits might provide the physical guidance support needed to improve the rate and extent of regeneration of peripheral nerves across injury gaps. In this study, we examined basic issues of magnesium metal resorption and biocompatibility by repairing sub-critical size gap injuries (6 mm) in one sciatic nerve of 24 adult male Lewis rats. Separated nerve stumps were connected with poly(caprolactone) nerve conduits, with and without magnesium filaments (0.25 mm diameter, 10 mm length), with two different conduit filler substances (saline and keratin hydrogel). At 6 weeks after implantation, magnesium degradation was examined by micro-computed tomography and histological analyses. Magnesium degradation was significantly greater when the conduits were filled with an acidic keratin hydrogel than with saline (p < 0.05). But magnesium filaments in some animals remained intact for 6 weeks. Using histological and immunocytochemical analyses, good biocompatibility of the magnesium implants was observed at 6 weeks, as shown by good development of regenerating nerve mini-fascicles and only mild inflammation in tissues even after complete degradation of the magnesium. Nerve regeneration was not interrupted by complete magnesium degradation. An initial functional evaluation, determination of size recovery of the gastrocnemius muscle, showed a slight improvement due to magnesium with the saline but not the keratin filler, compared with respective control conduits without magnesium. These results suggest that magnesium filament implants have the potential to improve repair of injured peripheral nerve defects in this rodent model.

Pubovaginal sling using polypropylene mesh and Vesica bone anchors.

OBJECTIVES: To report preliminary results from a modified pubovaginal sling procedure using polypropylene mesh as the sling suspended by nonabsorbable sutures anchored to the pubic tubercle with Vesica bone anchors. METHODS: Thirty-five women with type III stress urinary incontinence (SUI) (with or without associated urethral hypermobility) or type II SUI with additional risk factors such as obesity, chronic obstructive pulmonary disease, or failed prior incontinence-correcting procedures underwent this modified pubovaginal sling procedure. Postoperative voiding status was evaluated during office follow-up visits and telephone surveys. RESULTS: With a mean follow-up of 8.4 months (range 2 to 18), 32 women (91.4%) were dry, 1 improved, and 2 remained incontinent. The pubovaginal sling procedure was the only operation performed in 46% of patients, with a mean operative time of 72 minutes, a mean estimated blood loss of 137 mL, and a mean hospital period of 2.3 days. Patients on whom concomitant gynecologic procedures were performed had a mean duration of surgery of 122 minutes, a mean estimated blood loss of 202 mL, and a mean hospitalization period of 2.9 days. Thirteen women had preoperative urgency that persisted in 31% of patients. De novo urgency developed in 3 patients. Seven women required prolonged suprapubic tube drainage but no patient remained in permanent retention. There has been no infection or erosion. CONCLUSIONS: Our experience with this modified pubovaginal sling procedure using polypropylene mesh and Vesica bone anchors showed excellent results with greater technical ease, minimal morbidity, and decreased hospitalization period when compared to a traditional pubovaginal sling performed in our hands. Additional follow-up will be needed to assess long-term efficacy.

Augmentation mentoplasty using Mersilene mesh.

Many different materials are available for augmentation mentoplasty. However, the optimal implant material for chin implantation has yet to be found. During the past several years, a number of experienced surgeons have turned to the use of Mersilene mesh. Mersilene mesh is a non-absorbable Dacron polyester fiber that can be conformed easily into layers to achieve tailored dimensions and shape. At the McCollough Plastic Surgery Clinic PA, Birmingham, Ala, 277 patients over a 10-year period underwent chin augmentation with Mersilene mesh implants. The material provides excellent tensile strength, durability, and surgical adaptability. The overall complication rate was 3.2% (nine patients); infection rate, 2.5% (seven patients); and removal secondary to infection, 1.7% (five patients). Based on this 10-year experience, Mersilene mesh remains our material of choice for chin augmentation.

An unusual complication of tracheostomy.

Synthetic pediatric tracheostomy tubes have been a major advance for both short- and long-term airway support. We present a late complication from the use of a Shiley silicone pediatric tracheostomy tube (Silastic), and its radiologic manifestations. To our knowledge, this complication has not been previously reported.

Vascular effects of sustained-release fibroblast growth factors.

Since the half-life of most angiogenic growth factors is several hours or less, sustained-release delivery would be optimal for their future clinical use. Two fibroblast growth factors, basic fibroblast growth factor (bFGF) and endothelial cell growth factor (ECGF), were delivered in two sustained-released modalities (poloxamer 407 and a gelatin sponge [Gelfoam]) to attempt to increase soft tissue vascularity. In vitro bioactivity of ECGF-poloxamer formulations was also tested on endothelial cell cultures. Among vascular-compromised skin flaps in rabbits, ECGF-poloxamer (N = 26), bFGF-poloxamer (N = 5), ECGF-poloxamer (N = 9, irradiated), and bFGF-Gelfoam flaps (N = 22) did not demonstrate significant differences in viability and vascularity compared to controls (p > .05). Irradiation had a detrimental effect on both flap vascularity and viability (p = .02). Future efforts for sustained delivery of angiogenic proteins are critical in order to make them clinically useful in wound healing.

Correlation between nasal width and maxillary incisal alveolar width in post-natal facial development.

The paired nasomedial processes of the prenatal developing face contribute to the formation of the nasal region as well as the alveolar segment of the maxillary four incisors. The objective of this investigation was to determine whether or not there is a common anatomic relationship between the transverse nasal dimension and the corresponding transverse alveolar dimension that is continued in the post-natal period. The corresponding transverse dimensions were measured on a longitudinal series of 120 A-P cephalograms. In addition, A-P cephalograms of 24 dried skulls and also of 19 individuals having severe craniofacial malformations were analysed. The mean difference between the nasal dimensions and the corresponding alveolar dimensions ranged from 0.14 to 1.72 mm in the various groups. However, the statistically significant correlation coefficients between the measured dimensions were low (range r = 0.36-0.57). The developmental stage did not affect this relationship. Crowding was not found to be a major factor explaining the variability, although sex was seen as a significant factor.