Basic Fibroblast Growth Factor Expression following Surgical Delay of Rat Transverse Rectus Abdominis Myocutaneous Flaps

Abstract

Partial transverse rectus abdominis myocutaneous (TRAM) flap loss in breast reconstruction can be a devastating complication for both patient and surgeon. Surgical delay of the TRAM flap has been shown to improve flap viability and has been advocated in "high-risk" patients seeking autogenous breast reconstruction. Despite extensive clinical evidence of the effectiveness of surgical delay of TRAM flaps, the mechanisms by which the delay phenomenon occurs remain poorly understood. To examine whether angiogenic growth factors such as basic fibroblast growth factor (bFGF) may play a role in the delay phenomenon, the authors studied the expression of bFGF in rat TRAM flaps subjected to surgical delay. Thirty-five female Sprague-Dawley rats were randomly assigned to one of four TRAM flap groups: no delay (n = 6), 7-day delay (n = 12), 14-day delay (n = 10), or 21-day delay (n = 7). Surgical delay consisted of incising skin around the perimeter of the planned 2.5 x 5.0-cm TRAM flap followed by ablation of both superior epigastric arteries and the left inferior epigastric artery, thus preserving the right inferior epigastric artery (the nondominant blood supply to the rectus abdominis muscle of the rat). TRAM flaps were then elevated after 7, 14, and 21 days of delay by raising zones II, III, and IV off the abdominal wall fascia. Once hemostasis was assured, the flaps were sutured back in place. All flaps were designed with the upper border of the flap 1 cm below the xiphoid tip. Three days after the TRAM procedure, postfluorescein planimetry was used to determine percent area viability of both superficial and deep portions of TRAM flaps. All rats were euthanized and full-thickness TRAM specimens were taken from zones I, II, III, and IV for enzyme-linked immunoabsorbent assay analysis of bFGF levels. Statistical testing was done by t test (percent viability) and two-way analysis of variance (bFGF levels). All delayed flaps had significantly higher bFGF levels when compared with all nondelayed control flaps (p < 0.05). The bFGF levels were not different in the rats that received TRAM flaps 7, 14, or 21 days after delay surgery. There was also no significant difference in bFGF levels among zones I through IV. Control rats had more peripheral zone necrosis compared with all delayed TRAM rats. All delayed flaps had a significantly higher area of flap viability superficially than nondelayed control flaps (p < 0.05). There was no difference in deep flap viability. Surgical delay of rat TRAM flaps is associated with improved flap viability and significantly elevated levels of bFGF over nondelayed TRAM flaps at postoperative day 3 after TRAM surgery. The increases in bFGF noted at this time point suggests that bFGF may play a role in the improved TRAM flap viability observed after delay surgery. Further investigation is needed to evaluate the role bFGF may play in the delay phenomenon.

Vascular Delay Revisited

“…Angiogenic cytokines/growth factors such as basic fibroblast growth factor (bFGF) 55 and vascular endothelial growth factor (VEGF) are increased following delay and lead to new blood vessel growth. 56 Carroll et al 57 demonstrated increased muscle perfusion in a canine model of latissimus dorsi muscle delay using bFGF administration and increased latissimus dorsi muscle survival in a mouse model following PDGF administration.…”

Visualized identification of the maximal surgical delay effect in a rat flap model

“…The surgical delay has been demonstrated to be a reliable procedure to improve pedicled flap's survival area, but so far, the optimal delay period is still a controversial issue, which may be 5 days, 7 days, 14 days, 21 days, or 8–10 days in the literature . Thus, how to determine the optimal delay time continues to be unknown in the clinical practice, because various surgical delay animal models and delay procedures may significantly influence the delay period of reaching the maximal delay effect . In addition, Holzbach et al and Myers and Cherry have demonstrated that the survival area of the postdelayed pedicled flaps is not proportional to the delayed duration.…”

Serie de Casos: Resolución de Patologías con Colgajo Preformado

“…Cuando se utiliza un expansor tisular genera una cápsula altamente vascular que contribuye a la vascularidad del colgajo. Otro beneficio de dicho implante es que facilita la disección en el segundo procedimiento, a pesar de que el colgajo es más grueso y proporciona piel para un cierre directo del sitio donador [7][8][9][10].…”