Distal Flap Necrosis Research Articles

Improved Skin Paddle Survival in Pectoralis Major Myocutaneous Flap Reconstruction of Head and Neck Defects

To examine our outcomes with skin paddle survival using pectoralis myocutaneous flaps in reconstruction of the head and neck. The pectoralis major myocutaneous flap has been associated with a notable incidence of distal skin necrosis and flap loss. Our experience has been favorable compared with that reported in the literature. Retrospective medical record review of 81 cases of pectoralis major muscle flap reconstruction performed in 78 patients from 1995 to 2008 using a flap harvest technique that is slightly different from the classic descriptions. Data were obtained regarding coexisting health conditions and perioperative complications, which were divided into major and minor categories. Major complications were defined as total flap failure or greater than 25% skin paddle loss. Minor complications and donor site complications included fistulas that were managed conservatively, wound dehiscence not requiring additional surgery, local infections, seromas, and hematomas. Of the 81 flaps performed, 22 complications were encountered. Total flap loss was not encountered in any patient. The overall major complication rate in myocutaneous flaps was 3 of 76 (4%), with these cases consisting of significant skin paddle loss. Minor complications occurred in 14 of 81 myofascial and myocutaneous flaps (17%). Donor site complications of the chest wall occurred in 5 of 81 flaps (6%). Skin paddle necrosis may be minimized with modifications of the classic technique. We believe that extension of the skin flap over the rectus sheath is the cause of distal skin flap necrosis. The pectoralis major myocutaneous flap remains a valuable reconstructive option in the head and neck.

Microvascular reconstruction of the columella using a small radial forearm free flap: a case report

Columellar defects can result from various causes, a number of methods have been described for the reconstruction using local, regional, or free flaps. When local tissues are not available due to the presence of scars, free flaps become the treatment of choice. We present the case of a columellar defect resulting from a distal necrosis of a forehead flap in total nasal reconstruction. The columella was reconstructed using a small radial forearm free flap and a conchal cartilage graft. The flap and the graft survived completely with a satisfactory cosmetic result and good respiratory function during the follow-up time of 2 years. The result was achieved in a single-stage operation: the patient did not need any further procedures to improve the nasal appearance. We propose that the radial forearm free flap may be an easy and reliable alternative among the surgical options for columellar defects when local tissues are not available.

Reconstruction in the buttock region using the local fasciocutaneous infragluteal (FCI) flap

Defects in the buttock region are frequent indications for plastic surgery and are caused by various mechanisms. Therefore, different flaps were introduced and are well established. However, all of them have their limitations in reconstruction because of their restricted arc of rotation. Hence, we indicated the use of the local fasciocutaneous infragluteal (FCI) flap for reconstruction of such defects in the buttock region. In a series of 14 patients, three of them being paraplegics, the authors used 15 local FCI flaps to cover defects in the buttock region. The defects were caused by pressure sores, pilonidal sinus infection with recurrence, an adenocarcinoma of the gluteal region, a massive abscess after intramuscular gluteal injection, lipodystrophy of the lateral gluteal region and by multiple operations after an infection of implanted hip-joint prosthesis. The median dimension of the flaps was 177 cm(2). Fourteen of the 15 flaps healed uneventfully. In one patient, a re-mobilisation of the flap was necessary after a minor, distal-flap necrosis. Closure of the donor site was possible in all patients without further trouble. One patient needed a second local FCI flap because of a new pressure sore on the contralateral sacral region. The FCI flap is not only a versatile and reliable free flap with different indications, but is also a good alternative as a local flap for defect reconstruction in the whole buttock region, as demonstrated in this study for the first time. It can be raised as a sensate flap without restrictions of mobility in ambulatory patients. The donor-site morbidity is minimal, and options for future flaps of the gluteal region are preserved.

Treatment of complex hand trauma using the distal ulnar and radial artery perforator-based flaps

The clinical value of distal ulnar or radial artery adipofascial perforator flaps is shown in a series of 30 patients with severe hand and wrist injuries and major soft tissue defects requiring coverage. There were 22 men and 8 women, aged 16-73 years. The defects were dorsal and/or palmar, with or without transpalmar or transcarpal amputation, or amputation of the thumb and/or the digits. Tendon injuries have been treated primarily or secondarily, or reconstructed using silicon rods. In all cases, after surgical debridement of the wound, reconstruction of the defect was done using distal ulnar (21 patients, in 3 patients primary reconstruction) and distal radial artery (11 patients; in 2 patients primary reconstruction and in 2 patients after necrosis of distal ulnar perforator flap) adipofascial perforator flaps. Minimum follow-up was 6 months. Two ulnar flap showed partial necrosis and were revised successfully by distal radial adipofascial perforator flaps. One radial and one ulnar flap showed 50% and 60% necrosis, respectively, and were revised by groin flaps. All donor sites healed uneventfully. Functional and cosmetic result was very good in 15 patients and good or satisfactory in the remaining. Range of motion of the wrist and hand joints was almost within normal limits (less than 25 degrees extension or flexion deficits). Distal ulnar and radial artery adipofascial perforator flaps for traumatic defects of the hand and wrist offer several advantages compared to other local flaps; they are easy to obtain and cover effectively both dorsal and palmar defects without significant functional deficits or donor site complications to the upper limb.

Soft-Tissue Reconstruction of an Open Tibial Wound in the Distal Third of the Leg

Over the past 4 years, a total of 33 patients, each with an open tibial wound in the distal third of the leg, underwent a skin-grafted muscle flap reconstruction according to the new treatment algorithm developed by the author. When the size of the soft-tissue defect was less than 50 cm, a pedicled medial hemisoleus muscle flap was used for the soft-tissue coverage (n = 20). If the soleus muscle was traumatized, a small free muscle flap (ie, gracilis) was then used (n = 3). When the size of the soft-tissue defect was greater than 50 cm, a larger free muscle flap (ie, rectus abdominis or latissimus dorsi) was selected (n = 10). All patients were followed for up to 4 years. Three patients with a medial hemisoleus muscle flap developed insignificant distal flap necrosis and were treated subsequently with debridement and flap advancement. Five patients with a free muscle flap required an additional operation, and 2 patients had a subsequent debulking procedure of the flap for contour improvement of the leg. Reliable soft-tissue coverage with a well-healed tibial wound, evident fracture healing, and good contour of the leg were achieved in all 33 patients during follow-up. Following this new treatment algorithm, a selected option for an open tibial wound in the distal third of the leg can provide reliable soft-tissue coverage for different sizes of open tibial wounds and may offer a more cost-effective approach for managing such a complex clinical problem.

Soft-Tissue Coverage of an Open Tibial Wound in the Junction of the Middle and Distal Thirds of the Leg With the Medial Hemisoleus Muscle Flap

A relatively simple but reliable option for soft-tissue coverage of a less extensive tibial wound in the junction of the middle and distal thirds of the leg has never been determined. In this series, the author reports his clinical experience utilizing the medial hemisoleus muscle flap as a local reconstructive option for management of this unique clinical problem. Over the past 2 years, 14 patients underwent a soft-tissue reconstruction of an open tibial wound (4 x 3 to 10 x 5 cm) in the junction of the middle and distal thirds of the leg with the proximally based medial hemisoleus muscle flap. Only the medial half of the soleus muscle was elevated, with attention to preserving critical perforators from the posterior tibial vessels to the flap while allowing adequate arc of flap rotation to cover the exposed fracture site and hardware. All patients were followed for up to 2 years. Only 1 patient developed insignificant distal flap necrosis and was treated with debridement and flap readvancement. All patients had primary healing of their wounds, reliable soft-tissue coverage, evidenced fracture healing, and good cosmetic outcome during follow-up. Therefore, the medial hemisoleus muscle flap described by the author can be a reliable local option for soft-tissue coverage of a less extensive tibial wound in the junction of the middle and distal thirds of the leg with good outcome and minimal morbidity.

Octyl-2-Cyanoacrylate Liquid Bandage as a Wound Dressing in Facial Excisional Surgery: Results of an Uncontrolled Pilot Study

Although cyanoacrylate tissue adhesives are frequently used in the closure of cutaneous lacerations and excisions, only a few reports comment on their usefulness as a dressing over sutured wounds. A new formulation of octyl-2-cyanoacrylate (Liquid Bandage; BAND-AID, Johnson & Johnson) is used as an occlusive protective film over minor cuts and scrapes. An uncontrolled pilot study to assess the safety, efficacy, and cost of Liquid Bandage as an occlusive dressing over sutured facial excisions. Patients undergoing excision of facial neoplasms were recruited. After conventional layered repair, Liquid Bandage was applied. On suture removal, the wounds were photographed and evaluated by three dermatologists, who assigned an overall outcome rating. The average cost of Liquid Bandage and routine wound care materials was calculated based on prices from three different pharmacies. Of the 18 wounds available at follow-up, 17 were assigned an overall outcome rating of good or excellent by at least one of the evaluators. Eleven wounds received an excellent rating from at least two of the evaluators. One case of distal flap necrosis occurred. Liquid Bandage proved to be less expensive than routine postsurgical wound care materials. Liquid Bandage dressing is safe and effective over sutured facial excisions.

The Reversed Medial Hemisoleus Muscle Flap and Its Role in Reconstruction of an Open Tibial Wound in the Lower Third of the Leg

The usefulness of a reversed hemisoleus muscle flap as a local reconstructive option for soft-tissue coverage of an open tibial wound in the lower third of the leg has never been acknowledged. Over the past 2 years, 8 patients underwent soft-tissue reconstruction of an open tibial wound (3 x 3 to 10 x 6 cm) in the lower third of the leg with the reversed medial hemisoleus muscle flap modified by the author. The flap was dissected with attention to preserve several critical perforators from the posterior tibial vessels to the flap as possible while allowing adequate turnover of the flap to cover the exposed tibia or hardware. There was no total flap loss, and limb salvage was achieved in all patients. Only 2 patients developed insignificant distal flap necrosis, and they were treated subsequently with debridement and flap readvancement. All patients had reliable healing of their tibial wounds, with good reconstructive and cosmetic outcomes of their flap reconstructions during follow-up. Therefore, the author believes that the reversed medial hemisoleus muscle flap can be a good choice for soft-tissue coverage of a sizable open tibial wound in the lower third of the leg and may be used successfully to replace free tissue transfer in selected patients.

Basal Cell Carcinoma of the Lip and Mentum

Basal Cell Carcinoma of the Lip and Mentum

The Distally Pedicled Peroneus Brevis Muscle Flap Anatomic Studies and Clinical Applications

Defects in the distal third of the lower leg with bone or tendon exposure may require local or free flap reconstruction. For small and moderate lesions, the distally pedicled peroneus brevis muscle flap may be an effective procedure with less morbidity than a free tissue transfer. Six cadaveric specimens were dissected to determine the location of distal pedicles and the flap type. This flap was found to be a Type IV flap, and the location of distal pedicle was always located within 6 cm from the fibula tip. This flap was performed on 6 patients to cover defects in the distal third of the lower leg. The defect areas were the pretibial region in 2 cases, the lateral malleolus in 3 cases, and the Achilles tendon in 1 case. The peroneus brevis muscle was detached from the uppermost point of the fibula to obtain enough length to cover the defect. All flaps survived except 1 that experienced distal flap necrosis. Minor complications included skin graft failure in 2 cases. However, the final results demonstrated a smooth contour that eliminated dead space. Limited donor site morbidity was obtained in all cases. The distally peroneus brevis muscle flap therefore offers an alternative for reconstructive surgeons dealing with soft tissue defects of the lower leg.

Reconstruction of Extensive Composite Mandibular Defects with Large Lip Involvement by Using Double Free Flaps and Fascia Lata Grafts for Oral Sphincters

Extensive composite mandibular defects involving large lip defects are the most difficult to repair among head and neck reconstructions. This study presents the authors' approach using double free flaps and fascia lata grafts for oral sphincters. Ten patients were studied after ablative oral cancer surgery. Segmental defects of the mandible ranged from 6 to 14 cm. Cheek defects ranged from 9 x 6 cm to 15 x 12 cm, and intraoral defects ranged from 9 x 7 cm to 16 x 16 cm. Upper lip defects ranged from 10 percent to 50 percent, and lower lip defects ranged from 50 percent to 90 percent. A fibula osteocutaneous flap was used for reconstruction of mandibular defects and intraoral lining, and an anterolateral thigh flap was used for cheek and lip defects. Then, a sheet of fascia lata graft was used to reconstruct the oral sphincter. The tendon graft was passed into the subcutaneous layers of the reconstructed lip, woven into the remaining orbicularis oris muscle of the lip, and anchored to the upper lip near the philtral columns to complete the oral ring with adequate tension. Free flap survival was 100 percent. Complications included one patient with neck hematoma and distal anterolateral thigh flap necrosis, three patients with neck wound infection, and one patient with osteomyelitis of the mandible. All but one patient had adequate oral competence. All the patients were able to resume a soft diet. The speech ability was nearly normal for all the patients, and all the patients had gained an acceptable appearance. For extensive composite mandibular defects combined with large lip defects, immediate reconstruction with double free flaps and a fascia lata graft for oral sphincter has proved to be a useful option for better functional and cosmetic results.

Octyl-2-Cyanoacrylate Liquid Bandage as a Wound Dressing in Facial Excisional Surgery

Background Although cyanoacrylate tissue adhesives are frequently used in the closure of cutaneous lacerations and excisions, only a few reports comment on their usefulness as a dressing over sutured wounds. A new formulation of octyl-2-cyanoacrylate (Liquid Bandage; BAND-AID, Johnson & Johnson) is used as an occlusive protective film over minor cuts and scrapes. Objective An uncontrolled pilot study to assess the safety, efficacy, and cost of Liquid Bandage as an occlusive dressing over sutured facial excisions. Methods Patients undergoing excision of facial neoplasms were recruited. After conventional layered repair, Liquid Bandage was applied. On suture removal, the wounds were photographed and evaluated by three dermatologists, who assigned an overall outcome rating. The average cost of Liquid Bandage and routine wound care materials was calculated based on prices from three different pharmacies. Results Of the 18 wounds available at follow-up, 17 were assigned an overall outcome rating of good or excellent by at least one of the evaluators. Eleven wounds received an excellent rating from at least two of the evaluators. One case of distal flap necrosis occurred. Liquid Bandage proved to be less expensive than routine postsurgical wound care materials. Conclusions Liquid Bandage dressing is safe and effective over sutured facial excisions.

Two Options for Perforator Flaps in the Flank Donor Site: Latissimus Dorsi and Thoracodorsal Perforator Flaps

Two types of perforators, septocutaneous and musculocutaneous, are found in the same donor site of the flank area, and two perforator flaps based on each perforator are clinically available. Therefore, it is necessary to distinguish them from one another using different nomenclatures. Accordingly, the perforator flap based on a musculocutaneous perforator is named according to the name of the muscle perforated, the latissimus dorsi perforator flap, and the perforator flap based on a septocutaneous perforator, located between the serratus anterior and latissimus dorsi muscles, is named according to the name of the proximal vessel, the thoracodorsal perforator flap. In this series of 42 latissimus dorsi perforator flaps, flap size ranged from 5 x 3 cm to 20 x 15 cm, and two complications were observed: a marginal necrosis in an extremely large flap (26 x 12 cm) and a failure caused by infection. The thoracodorsal perforator flap was used in 14 cases, including two cases of chimeric composition. Flap size ranged from 4.5 x 3.5 to 18 x 15 cm, with no complications. In the two patterns of perforator flap that the author used, initial temporary flap congestion was observed in five latissimus dorsi perforator flap cases and two thoracodorsal perforator flap cases, when the flap was designed as a large flap or a less reliable perforator was selected. However, the congestion was not serious enough to cause flap necrosis. Several techniques, such as T anastomosis or inclusion of an additional perforator or a small portion of muscle, are recommended to prevent the initial flap congestion, especially when an unreliable perforator is inevitably used or when a flap larger than 20 cm long is required. A small portion of the muscle was included in six cases, when an unduly large or improperly long flap was planned. All of the flaps were successful and ranged from 22 x 7 to 15 x 28 cm, except for one case of distal flap necrosis in an extraordinarily large flap measuring 34 x 10 cm. Diverse selection of the perforator flap is one of the great advantages of the flank donor site, providing it with wider availability and more versatile composition for reconstruction or resurfacing.

Use of dorsal ulnar neurocutaneous island flap in the treatment of chronic postburn palmar contractures

In the present study, the authors evaluated efficiency of the “dorsal ulnar neurocutaneous island flap” in the coverage of palmar defects resulting from radical release of selected chronic postburn contractures. Eight white male hands with palmar contracture were treated with this flap between November 2001 and December 2003. The mean follow-up period was 11.6 months. The flap, which was planned on the ulnar aspect of the forearm and the hand, is transferred to the palmar defect. The subcutaneous pedicle of the flap was skin-grafted to avoid tension. All operations were successful. Distal flap necrosis that healed by secondary intention was observed in one of the eight flaps. Seventy-five degrees was the maximum improvement in metacarpophalangeal (MP) joint extension achieved in the little finger. Grasp function of the hand dramatically improved and the bulk of the flap did not interfere with grasping. No recurrent palmar contracture was observed. The authors concluded that the dorsoulnar neurocutaneous island flap can be used effectively in the treatment of postburn palmar contractures. The safety of the flap can be enhanced by grafting the intervening skin between the pivot point of the flap and the palmar defect.

Posterior interosseous artery flap in traumatic hand injuries.

Nineteen cases of posterior interosseous artery (PIOA) flap were reviewed. The patients' mean age was 24 (range 14-53) years. Nine patients were operated on as emergencies, and 10 patients were treated electively. Mean time of delay after trauma was 7.8 h (range 2-20 h) in emergency cases. Nine of them were non-replantable amputations. Skin defects were between 1.9 x 2.4 cm and 5.0 x 12.0 cm. Mean hospitalization time was 2.2 (range 1-5) days. Mean flap sensation was evaluated as 2.83-6.65 with the Semmes-Weinstein evaluation scale (only 2 patients scored less than 3.61). Five patients presented with discoloration and coolness. Average subjective evaluation was 8.2/10. Mean web opening after first web reconstruction was 40 degrees. One posterior interosseous neuropraxia ( recovered in 4 months), one distal flap necrosis, and one flap lost (due to infection) occurred as early complications. Mean follow-up was 12.8 months (range 15 days to 30 months). PIOA flap applications have reduced the need for lateral arm and radial forearm flaps and also shortened hospitalization time in clinical practice.

Double reverse V-Y-plasty in postburn scar contractures: a new modification of V-Y-plasty

Several techniques have been defined to use in surgical treatment of postburn scar contractures. However, distal flap necrosis is frequently seen since most of these techniques require random-pattern flaps and there is often poor vascular supply to scar tissue. In the Z-plasty, V-Y-plasty and their analogues, excess tissue requires excision of the dog-ear. A new modification of V-Y-plasty, called “double reverse V-Y-plasty”, is discussed. Nineteen postburn scar contractures were successfully treated with double reverse V-Y-plasty. The postoperative results represent the versatility of this technique in the surgical treatment of postburn scar contractures, especially neck and extremities. There was no distal flap necrosis. Double reverse V-Y-plasty is effective and alternative to the current techniques in surgical treatment of every kind of postburn scar contractures with one or more contracture lines. It does not need any surgical knack. Advantages: (i) double reverse V-Y-plasty is safely useful, when skin tension across the contracture line is too great to use any local flaps; (ii) when superficial scarring is localized in the contracture site, it is superior to other local flaps because of rich vascularity and mobility; (iii) double reverse V-Y-plasty is advised to the inexperienced surgeon, since it is easy to use; (iv) color and texture matches are cosmetically acceptable, and the resultant contracture is as much as with other techniques; (v) there is no necessity to use excision of the dog-ear; (vi) it can be utilized under local anesthesia almost in all cases; and (vii) it requires a shorter period of operation, and hospitalization.

Improved dorsal random-pattern skin flap survival in rats with a topically applied combination of nonivamide and nicoboxil.

The effects of a topically applied combination of nonivamide and nicoboxil in improving skin perfusion and preventing distal flap necrosis were tested in a random-pattern dorsal skin flap model. Forty male Wistar rats were randomized into two groups (n = 20), and a standardized dorsal random-pattern skin flap was raised on each rat. Animals in the experimental group were treated with the topically applied drug combination four times per day for 6 days, whereas in the control group only a placebo ointment was applied each time. Skin flap viability was evaluated on day 7, and the extent of skin flap necrosis was compared between the two groups. The topically applied combination of nonivamide and nicoboxil resulted in a statistically significant decrease in skin flap necrosis, compared with the control group (mean percentage of skin flap necrosis in the nonivamide/nicoboxil-treated group, 22.6 +/- 6.0 percent; control group, 36.8 +/- 4.3 percent; p< 0.05). The topical combination of nonivamide and nicoboxil was effective in reducing ischemic necrosis in failing random-pattern skin flaps in this rat model. The results of this study suggest that such a topical drug application might have significant effects in the reduction of ischemic necrosis in the distal parts of skin flaps, and this treatment might also have applications as prophylactic therapy for risky skin flaps.

Les procédés de couverture cutanée dans le traitement des séquelles de l'ulcère de Buruli. À propos de 16 observations

Introduction. – Thirteen percents of the patients suffering from Buruli ulcer in Ivory Coast show sequels at a result of their spontaneous healing. The purpose of our study is to report and estimate the first series of the sequel treatment of Buruli ulcer, with standard reconstructive procedures used in plastic surgery. Method. – Sixteen patients totalizing 18 sequels were classified into 2 groups: • 13 patients showed functional sequels in connection with cicaticial retractions about level with joints; • 3 patients showed aesthetic sequels with no repercussion on the functional aspect. The surgical treatment included for the functional sequels, the excision of the retractile scar, the restoration of the underlying structures followed by the coverage of the defect with skin grafts or muscle or musculo cutaneous flaps and for aesthetic sequels, the excision of the scar tissues and the coverage with full-thickness skin grafts. Results. – The results were considered good because the patients found an acceptable physical activity again that enable some of them to resume a professional activity and others a school activity. Motherless, a certain number of complications are to be deplored: • 1 case of distal necrosis of a skin flap autonomized which required excision and conducted healing but without repercussions on the functional result; • 1 residual edema about level with the fingers at the time of the covering of a hand with a groin flap; • 1 haematoma at the donar site of a full-thickness skin graft. Conclusion. – Distance flaps are more advisable for hand sequels in Buruli ulcer considering the regional character of the disease and the necessity to preserve the main vascular axes about level with the hand. On the lower limb, autonomized skin flaps enable provide important tissue and preserve the major vascular axes of the lower limb.

Can angiogenesis induced by chronic electrical stimulation enhance latissimus dorsi muscle flap survival for application in cardiomyoplasty?

In cardiomyoplasty, the latissimus dorsi muscle is lifted on its primary neurovascular pedicle and wrapped around a failing heart. After 2 weeks, it is trained for 6 weeks using chronic electrical stimulation, which transforms the latissimus dorsi muscle into a fatigue-resistant muscle that can contract in synchrony with the beating heart without tiring. In over 600 cardiomyoplasty procedures performed clinically to date, the outcomes have varied. Given the data obtained in animal experiments, the authors believe these variable outcomes are attributable to distal latissimus dorsi muscle flap necrosis. The aim of the present study was to investigate whether the chronic electrical stimulation training used to transform the latissimus dorsi muscle into fatigue-resistant muscle could also be used to induce angiogenesis, increase perfusion, and thus protect the latissimus dorsi muscle flap from distal necrosis. After 14 days of chronic electrical stimulation (10 Hz, 330 microsec, 4 to 6 V continuous, 8 hours/day) of the right or left latissimus dorsi muscle (randomly selected) in 11 rats, both latissimus dorsi muscles were lifted on their thoracodorsal pedicles and returned to their anatomical beds. Four days later, the resulting amount of distal flap necrosis was measured. Also, at predetermined time intervals throughout the experiment, muscle surface blood perfusion was measured using scanning laser Doppler flowmetry. Finally, latissimus dorsi muscles were excised in four additional stimulated rats, to measure angiogenesis (capillary-to-fiber ratio), fiber type (oxidative or glycolytic), and fiber size using histologic specimens. The authors found that chronic electrical stimulation (1) significantly (p < 0.05) increased angiogenesis (mean capillary-to-fiber ratio) by 82 percent and blood perfusion by 36 percent; (2) did not reduce the amount of distal flap necrosis compared with nonchronic electrical stimulation controls (29 +/- 5.3 percent versus 26.6 +/- 5.1 percent); (3) completely transformed the normally mixed (oxidative and glycolytic) fiber type distribution into all oxidative fibers; and (4) reduced fiber size in the proximal and middle but not in the distal segments of the flap. Despite the significant increase in angiogenesis and blood perfusion, distal latissimus dorsi muscle flap necrosis did not decrease. This might be because of three reasons: first, the change in muscle metabolism from anaerobic to aerobic may have rendered the muscle fibers more susceptible to ischemia. Second, because of the larger diameter of the distal fibers in normal and stimulated latissimus dorsi muscle, the diffusion distance for oxygen to the center of the distal fibers is increased, making fiber survival more difficult. Third, even though angiogenesis was significantly increased in the flap, cutting all but the single vascular pedicle resulted in the newly formed capillaries not receiving enough blood to provide nourishment to the distal latissimus dorsi muscle. The authors' findings indicate that chronic electrical stimulation as tested in these experiments could not be used to prevent distal latissimus dorsi muscle flap ischemia and necrosis in cardiomyoplasty.

Can Angiogenesis Induced by Chronic Electrical Stimulation Enhance Latissimus Dorsi Muscle Flap Survival for Application in Cardiomyoplasty?

In cardiomyoplasty, the latissimus dorsi muscle is lifted on its primary neurovascular pedicle and wrapped around a failing heart. After 2 weeks, it is trained for 6 weeks using” chronic electrical stimulation, which transforms the latissimus dorsi muscle into a fatigue-resistant muscle that can contract in synchrony with the beating heart without tiring. In over 600 cardiomyoplasty procedures performed clinically to date, the outcomes have varied. Given the data obtained in animal experiments, the authors believe these variable outcomes are attributable to distal latissimus dorsi muscle flap necrosis. The aim of the present study was to investigate whether the chronic electrical stimulation training used to transform the latissimus dorsi muscle into fatigue-resistant muscle could also be used to induce angiogenesis, increase perfusion, and thus protect the latissimus dorsi muscle flap from distal necrosis. After 14 days of chronic electrical stimulation (10 Hz, 330 μsec, 4 to 6 V continuous, 8 hours/day) of the right or left latissimus dorsi muscle (randomly selected) in 11 rats, both latissimus dorsi muscles were lifted on their thoracodorsal pedicles and returned to their anatomical beds. Four days later, the resulting amount of distal flap necrosis was measured. Also, at predetermined time intervals throughout the experiment, muscle surface blood perfusion was measured using scanning laser Doppler flowmetry. Finally, latissimus dorsi muscles were excised in four additional stimulated rats, to measure angiogenesis (capillary-to-fiber ratio), fiber type (oxidative or glycolytic), and fiber size using histologic specimens. The authors found that chronic electrical stimulation (1) significantly (p < 0.05) increased angiogenesis (mean capillary-to-fiber ratio) by 82 percent and blood perfusion by 36 percent; (2) did not reduce the amount of distal flap necrosis compared with nonchronic electrical stimulation controls (29 ± 5.3 percent versus 26.6 ± 5.1 percent); (3) completely transformed the normally mixed (oxidative and glycolytic) fiber type distribution into all oxidative fibers; and (4) reduced fiber size in the proximal and middle but not in the distal segments of the flap. Despite the significant increase in angiogenesis and blood perfusion, distal latissimus dorsi muscle flap necrosis did not decrease. This might be because of three reasons: first, the change in muscle metabolism from anaerobic to aerobic may have rendered the muscle fibers more susceptible to ischemia. Second, because of the larger diameter of the distal fibers in normal and stimulated latissimus dorsi muscle, the diffusion distance for oxygen to the center of the distal fibers is increased, making fiber survival more difficult. Third, even though angiogenesis was significantly increased in the flap, cutting all but the single vascular pedicle resulted in the newly formed capillaries not receiving enough blood to provide nourishment to the distal latissimus dorsi muscle. The authors’ findings indicate that chronic electrical stimulation as tested in these experiments could not be used to prevent distal latissimus dorsi muscle flap ischemia and necrosis in cardiomyoplasty. (Plast. Reconstr. Surg. 111: 178, 2003.)