Metabolic adaptations in delayed skin flaps. Glucose utilization and hexokinase activity.

The distribution of glucose and hexokinase activity was determined in the epithelial tissue of delayed bipedicled skin flaps in guinea pigs. The periods of "delay" were 1, 3, 7, 14, or 21 days. The flap survival was maximal (100% of the flap) when the flap elevation was performed either 7 or 14 days following the "delay" procedure. When the flap elevation was performed 1, 3, or 21 days following the "delay" procedure, the result was partial necrosis. A differential distribution of epithelial glucose was found within the bipedicled flaps. The lowest glucose level (30% of normal) was at a distance of 2 to 3.5 cm from the end of the caudal pedicle during the first day after the "delay" procedure. This decreased glucose content recovered toward normal levels during the later part of the "delay" period. The bipedicled flaps exhibited increased hexokinase activity during the 3-week period of the "delay," and the responses of hexokinase activity and tissue glucose levels to the "delay" procedure were reciprocal in the caudal half of the flaps.     

Basic fibroblast growth factor expression following surgical delay of rat transverse rectus abdominis myocutaneous flaps

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.     

Free-style free flaps

Free-tissue transfer has become the accepted standard for reconstruction of complex defects. With the growth of this field, anatomic studies and clinical work have added many flaps to the armamentarium of the microvascular surgeon. Further advancements and experience with techniques of perforator flap surgery have allowed for the harvest of flaps in a free-style manner, where a flap is harvested based only on the preoperative knowledge of Doppler signals present in a specific region. Between June of 2002 and September of 2003, 13 free-style free flaps were harvested from the region of the thigh. All patients presented with an oral or pharyngeal cancer and underwent resection and immediate reconstruction of these flaps. All flaps were cutaneous and were harvested in a suprafascial plane. The average size of the flaps was 108 cm2 (range, 36 to 187 cm2), and the average length of the vascular pedicle was 10 cm (range, 9 to 12 cm). All flaps were successful in achieving wound coverage and functional outcomes without any vascular compromise necessitating re-exploration. Free-style free flaps have become a clinical reality. The concepts and techniques used to harvest a free-style free flap will aid in dealing with anatomic variations that are encountered during conventional flap harvest. Future trends in flap selection will focus mainly on choosing tissue with appropriate texture, thickness, and pliability to match requirements at the recipient site while minimizing donor-site morbidity.     

Further experiences with the pectoralis major myocutaneous flap for the immediate repair of defects from excisions of head and neck cancers.

In our experience with 14 pectoralis major myocutaneous flaps they have been very reliable for reconstructions in a variety of clinical situations--especially in the repair of defects from extensive cancer resections in the head and neck area, including orbital exenterations. The flaps can be transferred immediately, without a delay.     

Drug treatment and flap survival

Some investigators found that isoxsuprine, propranolol, or heparin would increase skin-flap survival in loose-skinned animals. We evaluated the effects of these three drugs in the pig, an animal with skin circulation similar to that of humans. Four hundred ventrally based skin flaps that have a proximal axial portion and a distal random portion were made on the flanks of 40 pigs. There were eight study groups: control, isoxsuprine preoperatively and postoperatively, propranolol preoperatively and postoperatively, isoxsuprine postoperatively only, propranolol postoperatively only, heparin, single-stage surgical delay, and two-stage surgical delay. Flap survival was improved by the two-stage surgical delay when compared with the control flaps, flaps from pigs receiving a drug, or flaps from pigs having a single-stage surgical delay (p less than 0.001). When compared with the control flaps, neither isoxsuprine, propranolol, heparin, nor single-stage surgical delay significantly increased flap survival.     

The use of scapular and parascapular flaps for cheek reconstruction.

This is a retrospective review of our experience with microvascular transfer of scapular and parascapular flaps for the correction of lateral facial contour deficiencies. Twenty-eight patients with congenital (n = 8) and acquired (n = 20) defects were treated with 30 flaps; two patients had bilateral flaps. The etiology of the defects included hemifacial microsomia (n = 2), oblique facial cleft (n = 1), Romberg's hemifacial atrophy (n = 5), neoplasm (n = 4), irradiation (n = 8), trauma (n = 4), tumor excision (n = 4), facial lipodystrophy (n = 2), and silicone granuloma (n = 2). The follow-up evaluation was from 2 to 13 years, with an average of 6 years. Fabrication of a facial moulage was part of the preoperative planning for each patient. These were compound flaps, including skin, deepithelialized skin, fat, fascia, and bone, if necessary. All flaps were constructed with an intact skin paddle for postoperative monitoring. Based on dissections and anatomic findings at operation, several variations in the level of emergence of the circumflex scapular artery from the triangular space and its branching patterns were noted. All flaps survived; changes in the patients' weights were reflected in the flaps. Twelve patients required secondary procedures: excision of skin monitor islands, scar revisions, debulking, or flap resuspension to the malar region. Bone grafts or alloplastic implants were necessary in four patients in whom the malar eminence could not be adequately corrected by transfer of a flap. The deepithelialized scapular/parascapular flap is preferred for correction of large lateral facial defects.     

Clinical definition of independent myocutaneous vascular territories.

The use of myocutandous flaps can increase the possibilities for construction in many cases by bringing in new blood supply to avascular areas by furnishing additional bulk for filling defects or covering bone grafts or other deep repairs, and sometimes by making longer flaps viable. Also, the need for delay procedures is decreased and sometimes avoided. In this paper we define the vascular territories of 13 clinical myocutaneous flaps, and we describe possible uses of them. Three illustrative clinical cases are presented, in which repairs were done with these flaps. The future uses of these flaps challenge the imagination. Knowledge about them may significantly alter the traditional approaches to flap designs and repairs.     

Clamp delay: an effective new method of nonsurgical delay

This study introduces an effective new method of nonsurgical delay. In this new method, a special clamp that compressed a bipedicled skin fold along the sides of a proposed flap was glued to rat dorsa. The study also used a control group of untreated flaps and a group of flaps delayed by the conventional surgical procedure involving conventional parallel incisions. Eight days later, 1 x 6 cm reverse McFarlane flaps were isolated from the wound and raised. After 5 days, the survival length of the flaps was measured. Viability of the flaps delayed by the clamps [40.5 +/- 2.0 mm (mean +/- standard error); n = 10] did not differ from that of surgically delayed flaps (41.3 +/- 3.6 mm; n = 8) and was significantly higher (p < 0.001) than the survival of control flaps (26.3 +/- 0.6 mm; n = 10). Clamp delay can be useful in flap research that explores the relative significance of the vessel obstruction and biochemical processes that follow the surgical delay procedure. This method also offers a new perspective by introducing the concept of nonsurgical delay into clinical practice.     

Hemisoleus and reversed hemisoleus flaps

This paper reports an anatomic study of the soleus muscle and clinical applications of the findings derived from the study. Soleus neurovascular anatomy was studied in 86 limbs by dissection and specimen angiography. A consistently present bipenniform muscle morphology was found with medial and lateral subunits that had independent distal neurovascular supplies. This anatomic feature allows surgically splitting the muscle for transfer of one-half the muscle as a flap (hemisoleus muscle flaps). A series of 33 patients using both medial and lateral hemisoleus flaps in both proximally and distally based transfer is analyzed and illustrative examples are presented. The primary value of this technique is the ability to retain one-half the innervated soleus muscle in situ to preserve foot plantar flexion power in ambulatory patients. In addition, hemisoleus flaps have an extended arc of rotation as compared with that of conventional soleus muscle flaps.     

The vasculature and clinical application of the posterior tibial perforator-based flap.

Use of the posterior tibial flap pedicled on the posterior tibial vessels has been described by several authors, but with it there is the major disadvantage of an unavoidable transection of the posterior tibial artery. To overcome this disadvantage, we anatomically studied the perforators from the posterior tibial artery and used posterior tibial perforator-based flaps clinically. Based on our anatomic study of 25 cadaveric legs, the cutaneous perforators were considered to be distributed from the distal to the proximal sides of the lower leg through the medial border of the tibia, and they were classified into three types: septocutaneous perforators mainly located in the distal third of the leg, muscle perforators located in the proximal half, and periosteal perforators in the proximal third of the leg. The average size and number of perforators was 0.8 mm and 3.1 in one leg, respectively. A considerable number were located at sites from 70 to 140 mm superior to the medial malleolus. Based on our clinical cases repaired with flaps, we consider this flap to be useful as a free flap for the repair of defects of the extremities and as an island flap for reconstruction of defects on the anteromedial aspect of the lower leg. The territory of the flap is relatively wide, being 19 x 13 cm. The long saphenous vein can be used safely as the venous drainage system in the case of free-flap transfer.     

Prevention of skin flap necrosis by a course of treatment with vasodilator drugs.

Large island skin flaps, comprising the entire abdominal covering in rats, were raised on one neurovascular pedicle in the groin. A standard area of necrosis was produced on the other side from the pedicle. However, when the animals were treated with certain vasodilator drugs for 15 days before and 7 days after the flaps were raised, there was little or no necrosis. The effect of the drug therapy was the same as a surgical delay.     

Altered neutrophil function following reperfusion of an ischemic myocutaneous flap.

The neutrophil has been implicated as a source of oxygen free radicals provoking the reperfusion injury in various ischemic organs. This provided the motivation to explore the pathophysiologic role of the neutrophil in a swine model of postischemic latissimus dorsi myocutaneous flaps. Neutrophil function, neutrophil sequestration, and the anatomic distribution of muscle injury were estimated following a 6- to 8-hour global ischemic insult. Neutrophil function as measured by phorbol myristate acetate-stimulated superoxide production was found to be enhanced on reperfusion of ischemic flaps (n = 17). Neutrophil sequestration estimated from the arterial-venous difference of flap blood (n = 12) demonstrated that postischemic flaps more avidly sequester neutrophils than nonischemic flaps. The anatomic distribution of muscle injury (n = 7) was predominantly localized to the proximal portion of the ischemic flap. The enhanced functional response exhibited by neutrophils reperfusing an ischemic myocutaneous flap supports an active neutrophil role in the mediation of reperfusion injury.     

The versatile gastrocnemius myocutaneous flap.

The medial and lateral gastrocnemius myocutaneous flaps are described. Their usefulness, as direct flaps without a delay, in reconstruction of the lower extremity is described. In our practice, this flap has supplanted the cross-leg flap for most reconstructions in the lower extremity.     

The effective duration of the delay phenomenon in the rat.

In standard skin flaps in the rat, the effect of a delay was undetectable for the first 3 weeks and the maximum benefit was not apparent until the sixth week. At all time intervals the delay phenomenon was not as pronounced in the rat as in other species. The delay phenomenon in the rat lasts at least 30 weeks. The rat does not appear to be an ideal model for the study of skin flaps.     

Tissue oxygen measurements in delayed skin flaps: a reconsideration of the mechanisms of the delay phenomenon

The delay phenomenon was studied by measuring tissue oxygen tension (PsqO2) for 3 weeks in delayed flaps and normal adjacent contralateral skin in seven mongrel dogs. The PsqO2 fell after elevation of a bipedicle flap and rose again to normal by day 14. Delivery of oxygen to this flap was improved by surgical delay, so that when the bipedicle flap was reelevated on day 14 and its distal pedicle divided, minimal changes in PsqO2 occurred. When the control area was elevated on day 14 as a random-pattern flap, it had higher PsqO2 values than measured in the bipedicle flap on day 0, and therefore, it too had participated in the delay phenomenon, even though only its midline edge had been incised. An anatomic explanation for the findings was sought in wounds made in 10 rabbit ear chambers. After injury, blood flow was seen to be rerouted parallel to the incision line and was increased first by vasodilation and then also by angiogenesis until about day 14. Rerouting of blood by injury, inflammation, and angiogenesis due to repair appears to account for a significant portion of the delay phenomenon.     

Male perineogenital anatomy and clinical applications in genital reconstructions and male-to-female sex reassignment surgery

To determine the possibility of providing alternative surgical techniques for male genital reconstruction and for male-to-female sex reassignment surgery, the authors undertook an anatomic investigation of the perineogenital region in male cadavers. Anatomic dissection was performed on 14 male adult human cadavers (fresh and formalin-preserved) studying the main afferent vessels to the anterior perineal region and their mean internal diameters: deep external pudendal artery (0.60 mm), superficial perineal artery (0.50 mm), and funicular artery (0.37 mm). We established their exact topography, together with vascular anatomic variations, main vascular anastomosis circuits (base of the penis, scrotal septum, and perineal fat and lateral spermatic-scrotal fascia), angiosomes, anatomy of the rectovesical septum cavity, and their "critical" key points of dissection. The authors discuss the clinical possibility of elevation of a "tree" of previously described paragenital-genital flaps including mainly those based on the terminal branches of the internal pudendal vascular system, the erectile tissue pedicled flaps, and finally, flaps of the external pudendal system. The authors indicate the concrete vascularization system for each flap.     

The adductor flap: a new method for transferring posterior and medial thigh skin

Skin flaps from the medial aspect of the thigh have traditionally been based on the gracilis musculocutaneous unit. This article presents anatomic studies and clinical experience with a new flap from the medial and posterior aspects of the thigh based on the proximal musculocutaneous perforator of the adductor magnus muscle and its venae comitantes. This cutaneous artery represents the termination of the first medial branch of the profunda femoris artery and is consistently large enough in caliber to support much larger skin flaps than the gracilis musculocutaneous flap. In all 20 cadaver dissections, the proximal cutaneous perforator of the adductor magnus muscle was present and measured between 0.8 and 1.1 mm in diameter, making it one of the largest skin perforators in the entire body. Based on this anatomic observation, skin flaps as large as 30 x 23 cm from the medial and posterior aspects of the thigh were successfully transferred. Adductor flaps were used in 25 patients. On one patient the flap was lost, in one the flap demonstrated partial survival, and in 23 patients the flaps survived completely. The flap was designed as a pedicle island flap in 14 patients and as a free flap in 11.When isolating the vascular pedicle for free tissue transfer, the cutaneous artery is dissected from the surrounding adductor magnus muscle and no muscle is included in the flap. Using this maneuver, a pedicle length of approximately 8 cm is isolated. In addition to ample length, the artery has a diameter of approximately 2 mm at its origin from the profunda femoris artery. The adductor flap provides an alternative method for flap design in the posteromedial thigh. Because of the large pedicle and the vast cutaneous territory that it reliably supplies, the authors believe that the adductor flap is the most versatile and dependable method for transferring flaps from the posteromedial thigh region.     

Increased survival and vascularity of random-pattern skin flaps elevated in controlled, expanded skin

Controlled clinical tissue expansion, a new technique of providing donor tissue, results in an increase in surface area of expanded skin. The aim of the present study was to determine the effect of controlled tissue expansion on the surviving lengths of random-pattern skin flaps elevated in expanded tissue. In five pigs the surviving lengths of flaps raised in skin expanded for 5 weeks using a 250-cc rectangular Radovan-type tissue expander were compared with the survival lengths of flaps elevated in tissue in which a similar prosthesis was not expanded, bipedicle flaps delayed for 5 weeks, and control acutely raised random-pattern flaps. The expanded flaps had a mean increase in surviving length of 117 percent over control flaps, which was statistically significant. The delay flaps had an increase in survival of 73 percent over control flaps, which was also statistically significant. There was no significant difference in survival between expanded flaps and delayed flaps. Morphologic studies using radiographic techniques on one pig demonstrated increased vascularity with tissue expansion. The results of this work demonstrate that in addition to providing increased surface area with controlled expansion, flaps raised in expanded skin have a significantly augmented surviving length. The mechanism for this increased vascularity with expansion is not known at this time, but it may be due to physical forces associated with expansion acting as a stimulus for angiogenesis.     

Measurement of skin blood flow in delayed deltopectoral flaps, using local clearance of 133Xenon.

A study was made to determine the skin blood flow at the deltoid region in 89 cases, and the regional blood flow of delayed deltopectoral flaps, using the local clearance of 133Xe. The change in the skin blood flow, before and after a delay procedure of the deltopectoral flap, was measured in 27 patients--and the following results were obtained. (1) There was a linear tendency to a decreasing flow, one found to be statistically significant, with increasing age of the patient. (2) A significant correlation was found between the skin blood flow and the blood flow of the subcutaneous tissue. (3) The blood flow after we raised one side of a deltopectoral flap and lined it with a split-skin graft was higher than that found after a U-shaped undermining and not lining a flap. (4) The rate of successful transfer of a deltopectoral flap was found to be low when the 133Xe clearance rate was less than 0.07.     

Regional intravascular sympathetic blockade for better results in flap surgery: an experimental study of free flaps, island flaps, and pedicle flaps in the rabbit ear

Flap survival is still a major problem in reconstructive surgery. Increased flap survival after systemic administration of drugs inhibiting the adrenergic system has been reported in experimental studies. The clinical use, however, is restricted by systemic side effects. It has been demonstrated that, using guanethidine, an effective regional intravascular sympathetic (RIS) block can be obtained without systemic effects. Using this type of block, an experimental study was made on the survival and quality of different types of flaps in the rabbit ear. The results obtained in 72 flaps created in the ears of 36 rabbits were assessed by the extent of flap edema, peripheral neovascularization, flap temperature, and flap surviving area. The RIS block reduced edema and scab formation, caused higher flap temperatures, better neovascularization, and increased surviving flap area, as compared with equal flaps in the untreated contralateral ear of the same animal. The effect of RIS block may be considered as a "pharmacological delay" procedure. From the experiments as well as clinical experience, it may be concluded that this technique is a safe and effective procedure. Therefore, the RIS block method is recommended for clinical use in flap techniques in extremities of man.