Pedicled and free TRAM flaps in breast reconstructions : a comparative study

Detta är en avhandling från Stockholm : Karolinska Institutet, Department of Surgical Science

Sammanfattning: The transverse rectus abdominis musculocutaneous (TRAM) flap is frequently used when autologous tissue is desired for breast reconstruction, and it can be transferred pedicled or free. The pedicled TRAM flap is elevated as a lower transverse abdominal flap with the rectus abdominis muscle attached in the epigastric area, by which means the deep superior epigastric vessels nourish the flap. The flap is tunneled to its new position on the thoracic wall. The free TRAM flap consists of the same skin-fat paddle but the vascular pedicle consists of the deep inferior epigastric artery and vein. This artery is usually the dominant supplier of the flap area. The flap is raised with a small portion of the rectus muscle, disconnected and anastomosed to recipient vessels in the axillae or to the internal mammary vessels. The free flap procedure is more time- and resource-consuming, requiring microsurgery. If the anastomoses do not function, the whole flap is lost. On the other hand, the pedicled TRAM flap carries a greater risk of partial flap loss and subsequent longer healing than the free flap. It is therefore important to evaluate whether one technique is superior to the other. The most serious complication in all flap surgery is insufficient blood circulation, leading to changed metabolism in the tissue. The microdialysis technique provides a new way to survey local metabolic changes in flaps. A slower stabilization with remaining ischemic signs, such as lower glucose and higher lactate and glycerol values, was found in flap zones with inferior circulation. More pronounced ischemic signs, but a faster recovery were seen in free TRAM flaps than in pedicled ones. The fact that the metabolites returned to normal earlier in the free flaps than in the pedicled flaps indicates better perfusion. Trunk muscle strength after TRAM flap surgery was evaluated prospectively as more of the rectus abdominis muscle is included in the pedicled than in the free TRAM flaps. An isokinetic dynamometer (KIN-COM) was used to objectively assess maximal voluntary muscle strength preoperatively and up to one year postoperatively. A transient decrease in abdominal strength in both groups occurred at 6 months but was essentially regained at 12 months. The use of pedicled or free TRAM flap did not influence postoperative abdominal strength per se. Large individual variations indicated more important factors than the type of surgery. As alteration of sensibility is unavoidable when transferring tissue, the somatosensory status (tactile and thermal perception thresholds, i.e., warmth, cold, heat pain, cold pain, measured by von Frey's hair and Termotest, respectively) was assessed quantitatively at least two years postoperatively. No clinically relevant differences between pedicled and free TRAM flaps were demonstrated. The somatosensory status was still impaired compared to a control group, but the majority of patients in both groups reported that the reconstructed breast felt like a real breast. A new thermoplastic cast system was introduced to evaluate breast volume. The method is simple and can measure the contralateral breast volume preoperatively in a delayed breast reconstruction, indicating the volume of the planned TRAM flap. It is also sufficiently accurate to evaluate breast symmetry after breast reconstruction. Since a breast reconstruction is performed mainly to improve the quality of life of the patient, the most important issue would be the patient's satisfaction with the result. The esthetic result was evaluated subjectively and objectively. The free TRAM flap breast reconstructions gave a higher degree of breast symmetry as judged by both the patients and a three-member panel. These findings were supported by objective measurements, such as breast symmetry and breast volume. Satisfaction with the breast reconstruction and health-related quality of life did not differ statistically between the two groups. In conclusion, better perfusion was indicated in the free TRAM flaps as well as a better esthetic result in terms of breast symmetry. However, no findings favoring either technique were seen in terms of patient satisfaction, trunk muscle strength, or tactile and thermal sensibility.

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