Faculty Bibliography

Selection of ideal laser parameters for tissue welding is inhibited by poor understanding of the mechanism. We investigated structural changes in collagen molecules extracted from rat tail tendon (> 90% type I collagen) after tissue welding using an 808 nm diode laser and indocyanine green dye applied to the weld site. Mobility patterns on SDS-PAGE were identical in the lasered and untreated tendon extracts with urea or acetic acid. Pepsin incubation after acetic acid extraction revealed a reduction of collagen alpha and beta bands in lasered compared with untreated specimens. Circular dichroism studies of rat tail tendon showed absence of helical structure in collagen from lasered tendon. No evidence for covalent bonding was present in laser-treated tissues. Collagen molecules are denatured by the laser wavelength and parameters used in this study. No significant amount of helical structure is regenerated on cooling. We conclude that non-covalent interactions between denatured collagen molecules may be responsible for the creation of tissue welding

The effects of injury on peripheral nerve blood flow were studied, using a Laserflo blood perfusion monitor. A total of 11 nerves were studied, five normal and six injured nerves in four patients. Two of the patients had lacerating brachial plexus injuries, and two other patients had compressive neuropathies of their ulnar nerves at the elbow. All of the readings were taken intraoperatively while the patients were undergoing exploration and repair under general anesthesia. Measurements of the damaged nerves were taken serially from the site of injury proximally and distally, by approximating a flexible metric ruler to the dorsal aspect of the nerve along the same axis. In the acutely lacerated injured nerves (3 to 7 days), the measurements were taken at 1, 5, 10, and 20 mm. The maximal amount of retraction in any of the nerves was 1 cm; thus, the overall architecture of the nerves was maintained. In the compressed nerves, measurements were taken at 1, 2 and 3 cm proximal and distal to the medial epicondyle. Measurement of normal undamaged nerves was performed at six different sites along the same axis of the nerve. The averaged results indicate that the normal blood flow ranged from 47 ml/100 g/min to 63 ml/100 g/min, with a mean of 56 ml/100 g/min. In the injured nerves, blood flow was most depressed at sites closest to the laceration, and increased consistently and progressively at sites distant from the injury in both directions.(ABSTRACT TRUNCATED AT 250 WORDS)

There is no longer any doubt that free flaps can achieve the best breast reconstruction. Proof is the rapidly increasing popularity of the method. Its many advantages, the indications for each flap, and the technical refinements are presented

The real future of surgical lasers, and indeed of surgery itself, will depend on the integration of the surgeon into a system incorporating real-time tissue sensors, computer-directed robotic manipulation, and laser-tissue interactions that are customized to the clinical task. The human surgeon will operate as the central judgmental element in this mechanized and semiautomated laser surgical system. Only then will we really be able to make use of the subtle and varied laser-tissue effects now being discovered

Complete, stable chest-wall reconstruction was accomplished in a single operative procedure, using a fasciocutaneous free forearm flap based on the brachial artery. This allowed coverage of an extensive chest-wall defect

A technique for the construction of a frontal bar and a forehead plate as a single unit is described. This technique could be used in any procedure in which a frontal bandeau is advanced and the forehead needs to be remodeled. By using microscrew fixation, the bulkiness of miniplates and wires is eliminated