Biomedical subjects
Publications and source records attributed to C L Kerrigan.
The pig serves as an excellent model of skin flap research. Many flap types are available and flap designs can be modified easily for specific experimental requirements. Swine are large enough to permit multiple flaps and the skin color allows subjective observations of tissue circulation.
To better understand skin flap research, three pivotal papers of the last decade are reviewed. The validity of Milton's questioning the accepted length to width ratio is confirmed, whereas the shunt theory of skin flap failure is rejected, and the value of isoxsuprine treatment for preventing flap failure is debated. Current trends in three other areas of skin flap research are highlighted--skin flap metabolism, skin flap monitoring, and the use of musculocutaneous flaps for contaminated wounds.
Secondary ischemia time represents the interval between a postoperative vascular thrombosis of a free flap and its successful revascularization. Using an island-flap model in pigs, the skin was found to tolerate an average secondary ischemia time of 7.2 hours. The safe secondary critical ischemia time (10 percent probability of necrosis) is 4.7 hours. This compares with the primary ischemia times of 13.1 hours (average) and 7.0 hours (10 percent necrosis). The discrepancies between these observed values are discussed.
A new method of guide suture traction, the simple slip knot, is described. It is quick and easy with the added advantages of being adjustable as to the direction and amount of applied traction.
Reliable and repeatable means for the objective postoperative monitoring of skin flaps is a necessity. If a failing free flap can be recognized early, it can be salvaged by revision of the appropriate anastomoses. For the threatened distal portion of a conventional flap, external factors, such as kinking or hematoma, may be corrected or drug therapy instituted. We have analyzed blood from stab wounds in experimental pig flaps for pO2, pCO2, pH, and hematocrit. The results were compared with fluorescein penetration and flap surface temperature. The most significant finding was hematocrit readings of threatened flaps (54 percent) elevated above those of control flaps (35 percent). pH readings in the jeopardized flaps were 0.4 units below control. These two measures proved to be more reliable than intermittent temperature readings. In contrast to the fluorescein test, which can be used only once, stab wound analysis is repeatable at any time in the postoperative period. It can be effectively used to follow dynamic changes within a skin flap.
An experimental study was undertaken in pigs to clarify the pathophysiologic events occurring in a failing skin flap. It was demonstrated that skin flaps fail because of arterial insufficiency. Arteriovenous shunting is not a major cause of skin flap necrosis.
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An experimental pig flap model is presented with detailed operative technique. Studies employing this model are reported showing that difference in survival patterns depends on vascular configuration. Innervated island flaps were found to survive to the same length as denervated free flaps, and the onset of the benefits of the delay procedure occurred by the fourth postoperative day. The advantages of the pig and the pig buttock flap are discussed in detail.
Pigs with random skin flaps were treated with phenoxybenzamine, isoxsuprine, or reserpine. No significant increase in flap survival was detected. In selected animals, cutaneous blood flow was measured using the microsphere technique. Of the drugs tested, reserpine was the only one to cause a significant increase in cutaneous blood flow. Previous clinical and experimental studies on the treatment of failing skin flaps are reviewed. The important criteria for designing future pharmacologic studies are discussed.
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The intercostal island flap is a new omnipotential flap that is extremely valuable for torso reconstruction, provided one understands the intricacies of intercostal anatomy. Human cadaver dissections were done to determine the precise course and branching pattern of the lower (T7-T11) intercostal neurovascular bundles. On the basis of these dissections, the intercostal structures can be divided into four anatomical segments: vertebral, costal groove, intermuscular, and rectus. The anatomical segments can be safely combined in many ways to create versatile skin flaps. Three different clinical applications with requisite modifications in surgical technique are described in detail to exemplify important anatomical observations. The potential value of the intercostal island flap in reconstructive surgery is discussed.
The intercostal flap has many uses for torso reconstruction, whether employed as an island flap or a free flap. With modifications, it can be used as a sensory skin flap, or as a compound osteocutaneous flap to restore stability in a chest wall construction, or as a skin flap with a permanent blood supply to provide stable cover after excision of radiation ulcers.
CONTEXT: Although breast-conserving surgery (BCS) is less invasive than mastectomy and results in similar survival, many women eligible for BCS continue to undergo mastectomy. Whether the persistent use of mastectomy means that women do not understand their options or reflects an informed preference is unknown. OBJECTIVE: To learn which treatment surgeons would choose when asked to imagine that they themselves had early-stage breast cancer. DESIGN: Cross-sectional survey. SAMPLE: Convenience sample of 40 staff and resident surgeons attending surgical grand rounds at Dartmouth-Hitchcock Medical Center in 1998. MAIN OUTCOME MEASURE: Choice of BCS or mastectomy for the treatment of stage I breast cancer. RESULTS: Twenty-six male and 14 female surgeons participated in the survey. Half chose BCS and half chose mastectomy for treatment of their hypothetical early-stage breast cancer. Results did not differ by the sex of the surgeon. CONCLUSION: Even after being reminded of the equivalent 10-year survival statistics, half of the surgeons surveyed said that they would choose mastectomy over BCS for themselves. The assumption that BCS is the "right" choice for early-stage breast cancer may be unwarranted because many patients may have an informed preference for mastectomy.