PubMed Health⌕ Search

Biomedical subjects

W M Portnoy

Publications and source records attributed to W M Portnoy.

12 recordsLinked to original sources
PubMed1994

Deltopectoral island flap.

The medially based deltopectoral flap is a proven, reliable, and useful tool in the practice of head and neck and reconstructive surgery. Despite its versatility the flap has several limitations that restrict its use; these include a limited arc of rotation and significant risk of distal flap necrosis when increased length is incorporated from the deltoid region. By conversion of the conventional, parasternally based deltopectoral flap into an island flap supplied by one or two perforating branches of the internal mammary artery, its versatility can be markedly enhanced. This modification provides a free axis of rotation with virtually unrestricted spatial orientation and critical additional length. Furthermore, the island flap itself can be incorporated into the donor-site region, allowing primary closure of this defect. The dependability of this flap stems from the axial nature of the blood supply to the pectoral region. This factor, together with the free axis of rotation, affords the island flap its superiority over the standard deltopectoral flap. We have used this flap a total of 19 times (16 island and 3 free flaps) with notable clinical success and no observed failures. A description of technique and clinical applications will be discussed.

Aged↗
PubMed1993

Wound repair after fractionated external beam radiation therapy and concomitant hyperthermia in an experimental rat model.

BACKGROUND: Fractionated radiation therapy (RT) with adjuvant hyperthermia (HT) is being used in the treatment of cancer with noted clinical success. However, little information regarding wound repair in tissues receiving this combination therapy is available for comparison of surgical risk. Consequently, this study was undertaken to assess the effects of this combined therapy on wound healing by quantitatively evaluating wound repair using tensile strength measurements. METHODS: Four treatment cohorts were designated: sham control, RT alone (600 cGy/d for 4 days), HT alone (water bath at 41.8 degrees C, subcutaneous temperature of 41.0 +/- 0.5 degrees C for 60 minutes on days 1 and 4), and combined RT and HT. At 1 week after treatment, surgical incisions of the dorsal flank were made. Tensile strength measurements of wounds were obtained at 14 and 21 days after incision. RESULTS: No significant differences were observed in the combined treatment arm (RT and HT) compared with the reduced wound breaking strength of RT alone. Statistically significant differences in tensile strength were seen when the control group or HT alone was compared with RT and HT or RT alone. CONCLUSIONS: Concomitant exposure to fractionated RT and specific HT conditions demonstrated no disproportionate alteration in wound tensile strength compared with radiation exposure alone in this animal model.

Animals↗
PubMed1991

Cochlear implants as a contraindication to magnetic resonance imaging.

Magnetic resonance imaging poses little risk to the majority of patients undergoing scanning. However, cochlear implantation should pose a contraindication to this imaging process. This conclusion is based on several findings of in vitro testing of three cochlear implants: the 3M/House and 3M/Vienna designs and the Nucleus device. Specifically, tremendous torques are generated by each of these devices when they are introduced into the coil of a magnetic resonance imager; in addition, the 3M products not only were noted to induce an electrical current, but also were significantly magnetized and rendered afunctional. The clinical implications are discussed.

Cochlear Implants↗
PubMed1979

Digital beat-to-beat cardiotachometer.

A beat-to-beat cardiotachometer counting from 27 to 199 beats per minute has been constructed using digital integrated circuits. Power consumption is reduced, and accuracy enhanced, by incorporating a programmed read-only memory. This circuit technique can be employed for other devices, such as digital thermometers, in order to circumvent a nonlinear relationship between voltage and the physiological variable.

Computers↗
PubMed1975

An algorithm for on-line, real-time computer detection of ECG changes.

An algorithm for detection of ECG changes based on the Fourier transform is presented. The realisation of the algorithm was programmed on a minicomputer and could detect both large and subtle changes in an ECG waveform. The cardiac arrhythmias used in the study included normal sinus rhythm; premature atrial contraction; premature ventricular contraction; first, second, and third degree blocks; atrial and ventricular fibrillation and ventricular tachycardia. The algorithm was used to detect rhythm changes, but it is possible that, using it, a unique specification for a waveform at any frequency could be obtained.

Arrhythmias, Cardiac↗