Blood flow to a free flap may be impaired by thrombotic occlusion at the anastomosis or by microemboli occluding microvessels. The purpose of this study was to test the hypothesis that unfractionated heparin (UFH) or low molecular weight fractions of heparin (LMWH) could improve both the patency of microvascular anastomoses and microcirculatory perfusion. Sixty-six rats underwent orthotopic elevation of 3- x 10-cm epigastric free flaps. Animals received a single injection of either vehicle, UFH or LMWH, prior to microvascular clamp application and pedicle division. Anastomotic patency and tissue survival area were assessed on postoperative day 7. Anastomotic patency was significantly improved in both the UFH and LMWH groups. Total tissue survival area in those flaps with anastomotic patency was significantly improved in the UFH and the LMWH groups. Although both UFH and LMWH significantly elevated activated partial thromboplastin times (APTT) and anti activated clotting factor X (anti-Xa) activity over controls, UFH had its greatest effect on APTT, and LMWH on anti-factor Xa activity. Hematomas developed only in the UFH group. Thus, although both UFH and LMWH improved microcirculatory perfusion, as indicated by increased flap survival, only LMWH improved anastomotic patency while minimizing hemorrhage.

The latissimus dorsi-gluteus maximus flap represents an effective, economical option for the treatment of patients with subfascial infection after instrumented spinal fusion surgery.

A small device to detect eyelid closure was designed on the basis of a Hall-effect sensor. Accurate sensing of normal eyelid closure is required to develop a prosthetic eyelid closure device for patients with paralyzed orbicularis oculi muscles. In this study, six rabbits had the sensors surgically implanted. A Hall-effect sensor, a small device that measures magnetic fields, was implanted in the inferior eyelid near the ciliary margin. An opposing magnet was implanted in the upper eyelid. Thus, as the eyelid closes, the output of the Hall-effect sensor will increase. This output voltage was monitored weekly. During the first 5 weeks the output of the Hall-effect sensor decreased slightly but then reached a steady state for the duration of the experiment. This study suggests that the Hall-effect sensor could be used to detect normal eyelid closure in an implantable facial reanimation device.

A small device that can detect eyelid closure was designed using a Hall sensor and magnet. The ability of the sensor to differentiate blinks from saccadic motion is of vital interest in development of a device to alleviate complications of facial nerve paralysis. Twelve physically normal human subjects were used in this study. A small Hall sensor (3 x 2.5 x 1.1 mm), a device that detects magnetic fields, was attached to the lower eyelid near the lid margin, and an opposing small magnet (3 x 2 x 1 mm) was attached to the upper eyelid, also near the lid margin. Output potentials from the Hall sensor were monitored during eye blinks and saccadic eye movements to correlate sensor potentials with eye movements. Results indicate that the Hall sensor is effective at determining palpebral closure and discriminating eye closure from other eye movements. Therefore, we conclude that the Hall sensor is a reliable means for determining palpebral closure and is ideally suited for use in a facial prosthesis that uses the normal blink as a trigger to reanimate the contralateral paralyzed eyelid.

No abstract