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Reconstruction of complex thoracic defects with myocutaneous and muscle flaps
J
THORAC CARDIOVASC SURG
85:219-228, 1983
Reconstruction of complex thoracic defects with myocutaneous and muscle flaps Applications of new flap refinements This report describes reconstructions of complex thoracic defects with myocutaneous and muscle flaps that were modified by several recent refinements offlap design. These refinements comprise a second generation of myocutaneous and muscle flaps, which have substantially increased versatility and extended applications. as compared with the originally described flaps. These refinements include the following: (1) segmentally split latissimus dorsi and pectoralis major flaps. which transfer only one muscle segment as the flap and leave other segments of the same muscle in situ to preserve motor function; (2) pectoralis major fasciocutaneous flaps. which are extended by abdominal skin and fascia to provide longer. larger flaps: (3) reversed pectoralis major and latissimus dorsi flaps. which are supplied by secondary. distal vascular pedicles that permit flap use when the primary vascular supply is interrupted; and (4) island vascular pedicle muscle flaps. which allow intercostal passage for reconstruction of intrathoracic defects and cavities. The anatomic bases for these flap refinements are described. and the advantages provided are discussed.
Gordon R. Tobin, M.D., Constantine Mavroudis, M.D., W. Robin Howe, M.D., and Laman A. Gray, Jr., M.D., Louisville, Ky.
Myocutaneous and muscle flaps have become valuable instruments for management of complex wounds in all anatomic regions, and these flaps are widely recognized as having provided a major advancement in thoracic reconstruction. Several refinements in design of these flaps have been recently defined; these refinements create a second generation of these flaps with substantially increased versatility and extended applications, as compared with the original myocutaneous and muscle flaps. In the original (first generation) flaps, the entire muscle was transferred on the blood supply of the dominant vascular pedicle. The second generation of myocutaneous muscle flaps are designed with one (or more) of the following refinements: (l) Segmentally split flaps are surgically split into muscle segments beFrom the Divisions of Plastic and Reconstructive Surgery and Cardiovascular-Thoracic Surgery. Department of Surgery, University of Louisville. Louisville. Ky. Read at the Eighth Annual Meeting of The Samson Thoracic Surgical Society. San Diego, Calif., June 23-27. 1982.
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Address for reprints: Gordon R. Tobin, M.D .• Division of Plastic and Reconstructive Surgery, Department of Surgery, University of Louisville, Louisville. Ky. 40292.
Fig. 1. Anatomic basis for segmentally splitting latissimus dorsi flaps. Left side: Thoracordorsal vessels (TD) bifurcate proximally to supply medial (A) and lateral (5) muscle segments, which can be surgically split (dotted lines). Right side: Either muscle segment will independently carry skin paddles (P).
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Fig. 2. A. Roentgenogram of left chest wall and lung shotgun wound. B, Devitalized skin between entrance and exit wounds outlined for excision. Exit wound (E) destroyed the latissimus dorsi lateral muscle segment and vascular branch.
Fig. 2. Cont'd. C, Segmentally split latissimus dorsi myocutaneous flap, based on only the medial muscle segment, outlined. D, Successful chest wall reconstruction at 6 months.
tween major intramuscular branches of the neurovascular supply to allow independent transfer of only one segment. (2) Extended fasciocutaneous flaps are lengthened by skin and fascial extensions beyond the distal muscle border. (3) Reversed flaps are supplied by secondary distal vascular pedicles that extend coverage fields or allow use of the flap when its primary vascular pedicle has been interrupted. (4) Island vascular pedicle muscle flaps are transferred only on a single vascular pedicle for passage through intercostal spaces to intra-
thoracic defects when the muscle pedicle is too bulky. These refinements result from surgical exploitation of specific features of muscle structure and vascular anatomy. Although these refinements can be applied to many muscle and myocutaneous units, this paper will focus principally on these refinements applied to latissimus dorsi and pectoralis major flaps, since these muscles are the most frequently chosen flaps for thoracic reconstruction.
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This paper discusses each of the flap refinements and demonstrates their value with clinical examples of their applications in complex thoracic reconstructions.
Segmentally split flaps Both latissimus dorsi and pectoralis major muscleskin units may be split into independent segments that each contain major intramuscular branches of the primary vascular pedicle(s), and which may each be independently transferred without sacrificing function of the entire muscle. WeI, 2 recently reported anatomic studies of both latissimus dorsi and pectoralis major muscle-skin units that establish the anatomic basis for segmentally splitting flaps from these two muscles. These studies of muscle structure and intramuscular vascular anatomy are based on dissection, specimen angiography, and arterial dye perfusion of 115 latissimus dorsi and 95 pectoralis major muscle-skin units in human cadavers. We found independent neurovascular supplies to segmental branches of both muscles; thus each muscle segment can be surgically split from other segments by dissection along anatomic lines, and each can be independently transferred as a myocutaneous or muscle flap. Latissimus dorsi muscles have two segmental branches that are defined by the intramuscular courses of the two major branches of the thoracodorsal vessels and latissimus dorsi motor nerve (Fig. 1).1 The thoracodorsal neurovascular pedicle bifurcates in the axilla at the muscle neurovascular hilum. The upper neurovascular branch supplies the medial (upper) muscle segment, which originates on the thoracic peri spinal fascia. The lower neurovascular branches supply the lateral (lower) muscle segment, which originates on the iliac crest, lumbodorsal fascia, and lower-most ribs. The muscle can be surgically split between the two vascular branches into these two segments; either (or both) can be reliably transferred as a flap (Fig. 1). We have used three segmentally split latissimus dorsi myocutaneous flaps for chest wall reconstructions (Fig. 2) and/or cover of exposed axillary neurovascular structures. We 3 • 4 previously reported segmentally split latissimus dorsi flap applications in other anatomic regions.
Case reports CASE I. Closure ofaxillary and chest wall defect with split latissimus dorsi myocutaneous flap created from lateral segment. A shotgun discharge destroyed the skin and soft
tissue covering the right lateral chest wall and axilla and exposed the axillary vessels and brachial plexus of a 19-
Fig. 3. Left side (patient's right side): Anatomic basis for segmentally splitting pectoralis major flaps. Thoracoacromial vessel (TA) branches supply sternocostal (5) and clavicular (C) muscle segments. Lateral thoracic vessels (LT) supply external (abdominal) muscle segment (E). Muscle segments may be surgically split (dotted lines). Right side: Each segment independently carries a myocutaneous flap (P). year-oldman. A 12 by 29 cm skin paddle, carried on only the lateral segment of the split latissimus dorsi muscle, completely closed the defect. Direct closure of the cutaneous donor defect was accomplished. Complete flap survival, primary healing, and a full range of shoulder motion resulted. Latissimus dorsi motor function was preserved by the innervated medial segment of the split latissimus dorsi muscle left in situ. CASE 2. Closure of chest wall defect with split latissimus dorsi myocutaneous flap created from medial segment (Fig. 2). A shotgun discharge destroyed and devitalized an II by 19 cm area of left lateralchest wall of a 74-year-old man (Fig. 2, A and B). The lateral segment of the latissimus dorsi was destroyed by the exit wound. Gastric and diaphragmatic injuries were debrided and repaired. The chest wall defect was debrided and the open thorax closed by an II by 19 em skin paddle carried on the medial segment of the latissimus dorsi muscle (Fig. 2, C). Complete flap survival, primary healing, and thoracic closure resulted (Fig. I, D). The donor defect was closed by a split-thickness skin graft. Pectoralis major muscles have three segmental branches (sternocostal, clavicular, and external), which are defined by three independent neurovascular supplies (Fig. 3).2 The clavicular segment is supplied by the superior branch of the thoracoacromial vessels, the sternocostal segment is supplied by the inferior (pectoral) branch of the thoracoacromial vessels, and the external (abdominal) segment is supplied both by the lateral thoracic vessels and by lateral branches from the pectoral branch of the thoracoacromial vessels. The muscle can be surgically split between vascular
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Fig. 4. A, Closure of median sternotomy defect by bilateral split pectoralis major sternocostal segment muscle flaps (5) in a cadaver (with chest skin excised to show muscle-splitting technique). Clavicular (C) and external (E) muscle segments are left in situ to preserve donor motor function. B. Infected sternotomy wound dehiscence following coronary artery bypass procedure.
Fig. 4. Cont'd. C. Sternotomy defect closed with bilateral pectoralis major sternocostal segment advancement flaps (5). D. Primary wound healing, early hospital discharge, and preserved pectoralis muscle function resulted.
branches into these three segments, any of which can be transferred as a flap. We have used nine segmentally split pectoralis major myocutaneous or muscle flaps as follows: (l) chest wall reconstructions, (2) thoracoplasty and bronchopleuro-
cutaneous fistula closure, (3) closures of median sternotomy wound dehiscences (Fig. 4), (4) cover of exposed axillary vessels (Fig. 5), and (5) cover of an exposed saphenous vein graft to a segmental subclavian artery defect. We 2 • 4 previously reported application of
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Fig. 5. A. Rupture of bum scar contracture exposed axillary neurovascular structures (arrow). Split P. major sternocostal segment myocutaneous flap outlined. B. Result at 6 months. Myocutaneous flap allows a full range of shoulder motion. Clavicular and external muscle segments left in situ preserve donor motor function.
segmentally split pectoralis major flaps in other anatomic regions. CA SE 3. Closure of sternotomy dehiscence with pectoralis major muscle advancement flap created from sternocostal segment (Fig. 4). Wound infection and median sternotomy
dehiscence followed triple coronary artery bypass with saphenous vein in a 58-year-old man (Fig. 4, B). The wound was debrided and closed with bilateral muscle advancement flaps of the pectoralis major sternocostal segment (Fig. 4, C). Complete flap survival, primary healing, and mediastinal closure resulted (Fig. 4, D). Pectoralis major motor function was preserved by the clavicular and external muscle segments left in situ. CASE
4. Closure of axillary defect with split pectoralis
major myocutaneous transposition flap created from sternocostal segment (Fig. 5). Rupture of a severe burn scar
contracture of the right axilla exposed the axillary vessels and brachial plexus of a 45-year-old man (Fig. 5, A). The defect was closed with a 13 by 2I em mycutaneous transposition flap created from the sternocostal segment of the pectoralis major muscle. Complete flap survival, primary wound healing, and a full range of shoulder motion resulted (Fig. 5, B). Pectoralis major motor function was preserved by the clavicular and external muscle segments left in situ.
Extended fasciocutaneous flaps
Muscle-carried skin paddles may be extended well beyond the distal muscle borders by preserving vascular connections that extend to adjacent myocutaneous territories on the muscle fascia and in the overlying subcutaneous tissue. In the thorax, this flap refinement can be used to carry either abdominal or presternal skin on a pectoralis major muscle pedicle (Fig. 6).5-7 Rectus abdominis fascia and epigastric skin carried on pectoralis major fasciocutaneous flaps substantially lengthen the flaps and preserve breast position and substance (Fig. 7, C).5, 6 Presternal skin transferred on the pectoralis major muscle provides an alternative location for
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Fig. 6. Anatomic basis for extended P. major fasciocutaneous flaps. Left side (patient's right side): The pectoralis muscle carries an abdominal skin paddle (E) on rectus abdominus fascia (RF). Right side: A presternal skin paddle (P) also can be carried on the pectoralis major muscle.
a distal skin paddle but does not lengthen the flap substantially . 7 We used a pectoralis major fasciocutaneous flap extended onto the abdomen to reconstruct a precordial chest wall defect (Fig, 7). CAS E 5. Closure of chest wall defect with extended pectoralis major fasciocutaneous flap (Fig. 7). A 50-year-old
woman had recurrence of breast cancer I year after radical mastectomy on the left side and postoperative irradiation. Tumor excision required full-thickness removal of the precordial chest wall with exposure of the heart and lung (Fig. 7, A). The defect was stabilized with polypropylene mesh and covered with an epigastric skin paddle carried on the right pectoralis major muscle and rectus abdominis fascia (Fig. 7,
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Fig. 7. A. Chest wall resection for locally recurrent breast cancer. Exposed heart and lung covered with polypropylene mesh. B. Abdominal skin paddle (E) of extended pectoralis major fasciocutaneous flap outlined. C. Successful chest wall reconstruction. Note absence of breast displacement or disfigurement and primary closure of abdominal donor defect (arrow). B). Complete flap survival, primary wound healing, and tho-
racic closure resulted. Substance and position of the right breast were preserved (Fig. 7, C).
Reversed flaps
Both pectoralis major and latissimus dorsi flaps may be transferred on their caudal origins (reversed) because of secondary vascular supplies which are segmental, distal vascular pedicles, from internal mammary (to pectoralis major) and posterior intercostal (to
latissimus dorsi) vessels (Fig. 8).6. 8. 9 These secondary vascular pedicles will entirely support either flap when the primary vascular pedicles are interrupted. Reversed pectoralis major muscle flaps have been used to close median sternotomy wounds." However, we prefer to use split pectoralis major muscle advancement flaps developed from the sternocostal segment (Fig. 4) for sternal defects, because donor motor function is better preserved. Latissimus dorsi flaps can be reversed on posterior
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intercostal perforating vessels (Fig. 8).6,8 Usually, this maneuver is used to transpose the flap to flank, lumbar, or sacral defects. Reconstruction of a lateral thoracic defect with a reversed latissimus dorsi flap with its primary vascular pedicle destroyed by the original injury has been recently reported.!?
Island vascular pedicle muscle flaps Muscles may be converted to island vascular pedicle flaps that are transferred only on a single vascular pedicle (Fig. 9). This refinement can be used to permit flap transfer through intercostal incisions for closure of intrathoracic defects and cavities when intact muscle pedicles restrict transfer because of excess bulk or insufficient length. Well recently reported intrathoracic transfer of a rhomboid major muscle as an island vascular pedicle flap for successful repair of chronic esophagopleurocutaneous fistula (Fig. 9). Intrathoracic transfers of island vascular pedicle flaps are infrequently required, but this refinement can be valuable in specific instances. Intrathoracic transfer of latissimus dorsi myocutaneous flaps for repair of tracheoesophageal fistulas has also been recently reported.P
Clinical applications We have used the refinements of myocutaneous and muscle flaps described herein for successful reconstruction of complex thoracic and chest wall defects in 13 patients at the University of Louisville during the past 4 years. These applications include the following cases: (l) infected dehiscences of three median sternotomy incisions with exposure of saphenous vein grafts for coronary artery bypass, which were successfully closed with split pectoralis major muscle advancement flaps developed from the sternocostal segment (Fig. 4); (2) a simultaneous thoracoplasty and closure of a bronchopleurocutaneous fistula with a split pectoralis major muscle advancement flap developed from the sternocostal segment; (3) two massive chest wall defects, secondary to shotgun wounds, which were reconstructed with split latissimus dorsi (Fig. 2) and pectoralis major segmental flaps; (4) a precordial chest wall defect, secondary to resection of locally recurrent breast cancer, which was reconstructed with a pectoralis major fasciocutaneous extended flap (Fig. 7); (5) an exposed saphenous vein graft of the subclavian artery, which was covered with a split pectoralis major segmental muscle flap; (6) four wounds exposing axillary nerves and vessels, secondary to shotgun wounds or traumatically ruptured bum scar contractures, which were covered with segmentally split latissimus dorsi and pectoralis major myocutaneous flaps (Fig. 5); and
IP
Fig. 8. Anatomic basis for reversing latissimus dorsi flaps. Left side: Intercostal perforators (IP) provide a secondary vascular supply that supports the entire flap, or either of its segments. Right side: Skin peninsulas (P), or paddles, may be transferred on the reversed muscle, or its segments.
(7) a chronic esophagopleurocutaneous fistula, secondary to blunt trauma, which was closed by transfer of a rhomboid major muscle as an island vascular pedicle flap (Fig. 9).
Discussion Thoracic wounds present complex reconstructive challenges because of the following features: (l) Vital structures are often exposed. (2) Wound beds cannot be immobilized because of chest wall ventilatory excursion, pressure differences between the pleural cavity and atmosphere, and heart or great vessel pulsatile movement. (3) Flap access to cavitary defects and intrathoracic viscera is difficult because of the rib cage. (4) Exposed vein grafts are vulnerable to desiccation and rupture. (5) Bacterial contamination is frequently present. (6) Ischemic wounds frequently result from prior irradiation or scar deposition from chronic infection. Myocutaneous and muscle flaps are valuable in thoracic reconstruction because of their effectiveness and reliability in the presence of the anatomic and physiological challenges just described. The vigorous vascular supply of these flaps makes them our foremost reconstructive instrument for ischemic, contaminated, or poorly immobilized wounds. In the presence ofbacterial contamination, primary healing (rather than suppuration) is more common with these flaps than with skin flaps .13-15 The reliability of these flaps protects
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Fig. 9. A, Island vascular pedicle muscle flaps. Many muscles, or split muscle segmentsor myocutaneous units, can be transposed as islands on a single vascular pedicle. The rhomboid major (R), I. dorsi (LD), and P. major (PM) island flaps are shown here. B, Island vascular pedicle rhomboideus major muscle flap closure of an esophagopleurocutaneous fistula. The island muscle flap (R) is sutured over the esophageal defect. Successful esophageal repair and primary healing resulted. VP = vascular pedicle of the island rhomboid flap; E = esophagus; P = pericardium. vital structures and assures a continuing seal between pressure gradients. The size and bulk of these flaps address massive defects and intrathoracic cavities. These flaps provide a highly durable quality of cover. They allow options for immediate or elective secondary restoration of architectural stability and elimination of large flail regions.!" The flap refinements described herein preserve the virtues of myocutaneous and muscle flaps listed above and extend their reconstructive applications by increasing their versatility. Segmentally split flaps permit use of one muscle segment as a flap pedicle, with the other segments of the same muscle being left in situ to preserve donor motor function (Figs. 4 and 5).2, 3,17 Segmentally split flaps also allow use of a muscle segment as a flap when other segments of the same muscle are injured or destroyed (Fig. 2). Segmentally split flaps also permit reconstruction of two defects with independent branches of one flap." Extended fasciocutaneous flaps provide substantially longer and larger flaps (Figs. 6 and 7). These flaps also provide vascularized autogenous fascia for seal of pleural defects. In women, pectoralis major fasciocutaneous extended flaps avoid violating breast substance or position; the donor defect is located in the inframammary and epigastric areas (Fig. 7). Reversed pectoralis major and latissimus dorsi
flaps extend the field of coverage and allow use of these major muscle-skin units when their dominant vascular supplies are interrupted by the original injury or disease. 6, 8-10 Island vascular pedicle flaps provide flaps with small pedicles that can be passed through intercostal incisions for intrathoracic reconstructions when the muscle pedicle is too bulky or tethers the transfer (Fig. 9).11 This anatomic basis of flap refinement also allows free flap transfer and microvascular anastomoses for reconstructions in distant anatomic regions. Thus refinements of myocutaneous and muscle flaps substantially extend the versatility and application of these flaps for reconstruction of complex thoracic defects. REFERENCES Tobin GR, Schusterman MA, Peterson GY, Nichols G, Bland KI: The intramuscular neurovascular anatomy of the latissimus dorsi muscle. The basis for splitting the flap. Plast Reconstr Surg 67:637-641,1981 2 Tobin GR, Bland KI, Adcock R: Surgical anatomy of the pectoralis major muscle and neurovascular supply. Surg Forum 32:573-575, 1981 3 Tobin GR, MobergAW, DuBouR, WeinerU, Bland KI: The split latissimus dorsi flap. Ann Plast Surg 7:272-280, 1981
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4 Tobin GR, Spratt JS, Bland KI, Weiner LJ: One-stage pharyngoesophageal and oral mucocutaneous reconstruction with two segments of one musculocutaneous flap. Am J Surg 144:489-493, 1981 5 MaGee WP, McCraw lB, Horton CE, Mcinnis WD: Pectoralis "paddle" myocutaneous flaps. The workhorse of head and neck reconstruction. Am J Surg 140:507-513, 1980 6 MaGee WP, Gilbert DA, Mcinnis WD: Extended muscle and musculocutaneous flaps. Clin Plast Surg 7:57-70, 1980 7 Sharzer LA, Kalisman M, Silver CE, Strauch B: The parasternal paddle. A modification of the pectoralis major myocutaneous flap. Plast Reconstr Surg 67:753-762, 1981 8 Bostwick J, Scheflan M, Nahai F, Jurkiewicz MJ: The "reversed" latissimus dorsi muscle and musculocutaneous flaps. Anatomical and clinical consideration. Plast Reconstr Surg 65:395-399, 1980 9 Jurkiewicz MJ, Bostwick J, Hester TR, Bishop JB, Craver J: Infected median sternotomy wound. Ann Surg 191:738-744, 1980 10 Scheflan M, Bostwick J, Nahai F: Chest wall reconstruction. Manageme: of the difficult chest wound. Ann Plast Surg 8: 122-131, 1982 II Lucas AE, Snow NJ, Tobin GR, Flint LM Jr: Use of the rhomboid major muscle flap for esophageal repair. Ann Thorac Surg 33:619-623, 1982 12 Thesal BF, Clarke JS: Intrathoracic application of the latissimus dorsi musculocutaneous flap. Plast Reconstr Surg 66:842-845, 1980 13 Pappas C, Goldrick G, Cundy K, Wong W: Skin flaps vs. muscle flaps. Coping with infection in the presence of a foreign body. Plast Surg Forum 3: 133-135, 1980 14 Chang N, Mathes SJ: A comparison of the effect of bacterial inoculation on musculocutaneous and random pattern flaps. Plast Surg Forum 4:18-21,1981 15 Mathes SJ, Alpert BS, Chang N: Use of the muscle flap in chronic osteomyelitis. Experimental and clinical correlation. Plast Reconstr Surg 69:815-828, 1982 16 Arnold PG, Pairolero PC: Use of pectoralis major muscle flaps to repair defects of anterior chest wall. Plast Reconstr Surg 63:205-212, 1979 17 Tobin GR, Gordon JA, Smith B, Schusterman M: Preserving motor function by splitting muscle and myocutaneous pedicles. Plast Surg Forum 3: 160-161, 1980
Discussion DR. ROBERT W. JAMPLIS Palo Alto. Calif.
The advent of muscle and myocutaneous flaps has been one of the great advances in surgery in this past decade. Previously we were forced to use foreign material, such as Marlex mesh, or simply allow the defect to granulate in, with the many ensuing complications. I have had no personal experience with these flaps. It has been our policy for the surgeon to resect the lesion widely
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without regard to reconstruction and then to have the plastic surgeon fill in the defect. I think that this is the correct way to manage these cases. Obviously, the authors, who are plastic surgeons, and their thoracic surgical colleagues in Louisville, must feel the same way. The realization that most of the skin's blood supply comes from the perforating vessels from the underlying muscles is what makes this all possible. As an aside, in 1906 an Italian named Tansini created the first myocutaneous latissimus dorsi flap to reconstruct a breast. It is a mystery to me how three generations can go by without the efficacy of this technique being recognized. I think it was probably due to the old Geheirnrat professors in those days, whose minds were closed to anything new. Fortunately, we do not have that problem anymore, at least in the United States. The authors did extensive dissection on cadavers to determine exactly the distribution and extent of the perforators. This information, unavailable in ordinary textbooks of anatomy, is the basis for all of these second-generation flaps. With this information, it should be possible to map out a viable flap accurately and predictably and therefore avoid the disaster of massive flap necrosis. This slide shows a malignant fibrohistiocytoma. It was given preoperative irradiation, and that is the extent of the dissection. One of my former interns, who is now a colleague at Stanford in the plastic surgery department, Bill. McClure, did this latissimus dorsi flap. This other case was an aneurysmal bone cyst which someone attempted to excise elsewhere. Terrible bleeding ensued, and the surgeon had to close and use external pressure for several hours to stop it. This was eventually excised, and a reverse pectoralis major flap was done. These operations were done without using second-generation flaps, which I think are the whole point of this presentation. By using them one can preserve the motor function of the muscle as well. Finally, I would like to ask the authors if they have had any experience in microneurovascular procedures, and what will their role be, if any, in the future?
DR. JOHN R. BENFIELD Los Angeles. Calif.
I would like to ask a question and make a comment. Myocutaneous flaps are very useful in oncologic operations for reconstructive purposes. My question is this: What has been the incidence of flap necrosis requiring revision? Are there newer techniques for assessing viability of the flap? The comment I would like to make has to do with the use of myocutaneous flaps for the management of chest wall tumors. I believe that an incisional biopsy specimen of these chest wall tumors should be obtained before extirpation and major reconstructive procedures are undertaken. It is, in general, necessary to get a permanent section carefully studied by the pathologist, perhaps even with electron microscopy, before major resections are undertaken. This allows one to assess precisely what the tumor is and to decide
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whether or not adjuvant therapy should be used. Then one can decide when to undertake the extirpation and reconstructive procedure, rather than to see the mountain and climb it immediately because it is there. DR. DONALD L. MORTON Los Angeles. Calif:
The Thoracic Surgical Oncology team, Drs. E. Carmack Holmes, Kenneth Ramming, and I, have resected about 20 massive chest wall tumors of this type. Treatment of these massive chest wall tumors requires wide resection of the lesion and, as Dr. Benfield said, a knowledge of the extent of tumor involvement before any resection is attempted. We treat many of these tumors preoperatively with intra-arterial chemotherapy and radiation. For stabilization of the chest wall, we still believe that Marlex mesh is most important for reconstruction of large defects. For example, we treated a patient with recurrent carcinoma of the breast who had received radiation to the operative site. The defect was very large. In the first step, Marlex mesh was used to stabilize the chest wall. I would emphasize that a monofilament suture material, such as nylon, should be used because this type of material will permit treatment of infection, should one occur, without necessitating removal of the mesh. Another time, we treated an extensive lymphangiosarcoma in the same way, except that an omental pedicle was created from the abdomen before skin was grafted over the wound. There are many ways to manage these large defects in terms of coverage if the thoracic surgical oncologist and his colleagues in plastic surgery use their combined ingenuity and creativity. DR. TO BIN (Closing) I thank each of the discussers for his comments. Dr. Jamplis, I certainly agree with the importance you place on accurate anatomic studies as a basis for reliable application of the flaps that are in our contemporary armamentarium. In Louisville, we do indeed have a large experience with microneurovascular reconstruction. Our experience in upper and lower extremity reconstructions is probably second to none. However, microvascular free flap reconstructions of the thorax are rarely required. This is due to the anatomic proximity of large thoracic muscle-skin units, such as latissimus
Thoracic and Cardiovascular Surgery
and pectoralis, and their long vascular pedicles, which reach virtually all thoracic defects. We would choose these regional pedicle flaps over free tissue transfers, unless compelling reasons were present in an individual case. Quantitative bacteriology is a useful adjunctive measure in clinical judgment on wound closure. We have learned that these flaps manage moderately contaminated wounds better than conventional flaps, although no flap in any circumstance is a substitute for adequate drainage, debridement, and local wound care. Wounds contaminated under 1050rganisms.per gram of tissue will often heal per primum when closed with a muscle or myocutaneous flap; by contrast, conventional skin flaps often fail to prevent suppuration at that level of contamination. Thus muscle flaps are valuable adjuncts in contaminated wound management, and quantitative bacteriology aids in their appropriate use. No flaps, however, prevent suppuration when contamination is greater than 105 to 106 organisms per gram of tissue, and no flaps cure established infection. I agree with the principles of chest wall tumor management, as stated by Drs. Benfield and Morton. These correspond to our practices in Louisville. Dr. Morton, the excellent outcome of your patient endorses the reconstruction selected. Alternatives are few for massive anterior midline defects. One or both pectoralis major myocutaneous units, extended by abdominal skin and fascia, are helpful in this location. Also, if internal mammary-superior epigastric vessels are intact (I suspect they were not in the patient you presented), we now know that one third (or more) of the abdominal skin can be carried on one rectus abdominis muscle to the chest. Dr. Benfield raised the question of flap viability and adjuncts that can help predict survival. Of course, these flaps do have an incidence of failure. Unquestionably, muscle and myocutaneous flaps are substantially more reliable than flaps of the past. However, we have substantially increased the complexity of tasks that we ask of them. Thus we extend them to their limits and occasionally pass beyond their limits. We use systemic intravenous Fluorescein with ultraviolet fluorescence evaluation to make intraoperative judgments on the limits of flap dimensions. To date, this has been our most reliable tool. Currently we are experimenting with other techniques of intraoperative definition of flap dimension, as flaps will surely always be extended to the limits of their capabilities.
THORAC CARDIOVASC SURG
85:219-228, 1983
Reconstruction of complex thoracic defects with myocutaneous and muscle flaps Applications of new flap refinements This report describes reconstructions of complex thoracic defects with myocutaneous and muscle flaps that were modified by several recent refinements offlap design. These refinements comprise a second generation of myocutaneous and muscle flaps, which have substantially increased versatility and extended applications. as compared with the originally described flaps. These refinements include the following: (1) segmentally split latissimus dorsi and pectoralis major flaps. which transfer only one muscle segment as the flap and leave other segments of the same muscle in situ to preserve motor function; (2) pectoralis major fasciocutaneous flaps. which are extended by abdominal skin and fascia to provide longer. larger flaps: (3) reversed pectoralis major and latissimus dorsi flaps. which are supplied by secondary. distal vascular pedicles that permit flap use when the primary vascular supply is interrupted; and (4) island vascular pedicle muscle flaps. which allow intercostal passage for reconstruction of intrathoracic defects and cavities. The anatomic bases for these flap refinements are described. and the advantages provided are discussed.
Gordon R. Tobin, M.D., Constantine Mavroudis, M.D., W. Robin Howe, M.D., and Laman A. Gray, Jr., M.D., Louisville, Ky.
Myocutaneous and muscle flaps have become valuable instruments for management of complex wounds in all anatomic regions, and these flaps are widely recognized as having provided a major advancement in thoracic reconstruction. Several refinements in design of these flaps have been recently defined; these refinements create a second generation of these flaps with substantially increased versatility and extended applications, as compared with the original myocutaneous and muscle flaps. In the original (first generation) flaps, the entire muscle was transferred on the blood supply of the dominant vascular pedicle. The second generation of myocutaneous muscle flaps are designed with one (or more) of the following refinements: (l) Segmentally split flaps are surgically split into muscle segments beFrom the Divisions of Plastic and Reconstructive Surgery and Cardiovascular-Thoracic Surgery. Department of Surgery, University of Louisville. Louisville. Ky. Read at the Eighth Annual Meeting of The Samson Thoracic Surgical Society. San Diego, Calif., June 23-27. 1982.
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Address for reprints: Gordon R. Tobin, M.D .• Division of Plastic and Reconstructive Surgery, Department of Surgery, University of Louisville, Louisville. Ky. 40292.
Fig. 1. Anatomic basis for segmentally splitting latissimus dorsi flaps. Left side: Thoracordorsal vessels (TD) bifurcate proximally to supply medial (A) and lateral (5) muscle segments, which can be surgically split (dotted lines). Right side: Either muscle segment will independently carry skin paddles (P).
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Fig. 2. A. Roentgenogram of left chest wall and lung shotgun wound. B, Devitalized skin between entrance and exit wounds outlined for excision. Exit wound (E) destroyed the latissimus dorsi lateral muscle segment and vascular branch.
Fig. 2. Cont'd. C, Segmentally split latissimus dorsi myocutaneous flap, based on only the medial muscle segment, outlined. D, Successful chest wall reconstruction at 6 months.
tween major intramuscular branches of the neurovascular supply to allow independent transfer of only one segment. (2) Extended fasciocutaneous flaps are lengthened by skin and fascial extensions beyond the distal muscle border. (3) Reversed flaps are supplied by secondary distal vascular pedicles that extend coverage fields or allow use of the flap when its primary vascular pedicle has been interrupted. (4) Island vascular pedicle muscle flaps are transferred only on a single vascular pedicle for passage through intercostal spaces to intra-
thoracic defects when the muscle pedicle is too bulky. These refinements result from surgical exploitation of specific features of muscle structure and vascular anatomy. Although these refinements can be applied to many muscle and myocutaneous units, this paper will focus principally on these refinements applied to latissimus dorsi and pectoralis major flaps, since these muscles are the most frequently chosen flaps for thoracic reconstruction.
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This paper discusses each of the flap refinements and demonstrates their value with clinical examples of their applications in complex thoracic reconstructions.
Segmentally split flaps Both latissimus dorsi and pectoralis major muscleskin units may be split into independent segments that each contain major intramuscular branches of the primary vascular pedicle(s), and which may each be independently transferred without sacrificing function of the entire muscle. WeI, 2 recently reported anatomic studies of both latissimus dorsi and pectoralis major muscle-skin units that establish the anatomic basis for segmentally splitting flaps from these two muscles. These studies of muscle structure and intramuscular vascular anatomy are based on dissection, specimen angiography, and arterial dye perfusion of 115 latissimus dorsi and 95 pectoralis major muscle-skin units in human cadavers. We found independent neurovascular supplies to segmental branches of both muscles; thus each muscle segment can be surgically split from other segments by dissection along anatomic lines, and each can be independently transferred as a myocutaneous or muscle flap. Latissimus dorsi muscles have two segmental branches that are defined by the intramuscular courses of the two major branches of the thoracodorsal vessels and latissimus dorsi motor nerve (Fig. 1).1 The thoracodorsal neurovascular pedicle bifurcates in the axilla at the muscle neurovascular hilum. The upper neurovascular branch supplies the medial (upper) muscle segment, which originates on the thoracic peri spinal fascia. The lower neurovascular branches supply the lateral (lower) muscle segment, which originates on the iliac crest, lumbodorsal fascia, and lower-most ribs. The muscle can be surgically split between the two vascular branches into these two segments; either (or both) can be reliably transferred as a flap (Fig. 1). We have used three segmentally split latissimus dorsi myocutaneous flaps for chest wall reconstructions (Fig. 2) and/or cover of exposed axillary neurovascular structures. We 3 • 4 previously reported segmentally split latissimus dorsi flap applications in other anatomic regions.
Case reports CASE I. Closure ofaxillary and chest wall defect with split latissimus dorsi myocutaneous flap created from lateral segment. A shotgun discharge destroyed the skin and soft
tissue covering the right lateral chest wall and axilla and exposed the axillary vessels and brachial plexus of a 19-
Fig. 3. Left side (patient's right side): Anatomic basis for segmentally splitting pectoralis major flaps. Thoracoacromial vessel (TA) branches supply sternocostal (5) and clavicular (C) muscle segments. Lateral thoracic vessels (LT) supply external (abdominal) muscle segment (E). Muscle segments may be surgically split (dotted lines). Right side: Each segment independently carries a myocutaneous flap (P). year-oldman. A 12 by 29 cm skin paddle, carried on only the lateral segment of the split latissimus dorsi muscle, completely closed the defect. Direct closure of the cutaneous donor defect was accomplished. Complete flap survival, primary healing, and a full range of shoulder motion resulted. Latissimus dorsi motor function was preserved by the innervated medial segment of the split latissimus dorsi muscle left in situ. CASE 2. Closure of chest wall defect with split latissimus dorsi myocutaneous flap created from medial segment (Fig. 2). A shotgun discharge destroyed and devitalized an II by 19 cm area of left lateralchest wall of a 74-year-old man (Fig. 2, A and B). The lateral segment of the latissimus dorsi was destroyed by the exit wound. Gastric and diaphragmatic injuries were debrided and repaired. The chest wall defect was debrided and the open thorax closed by an II by 19 em skin paddle carried on the medial segment of the latissimus dorsi muscle (Fig. 2, C). Complete flap survival, primary healing, and thoracic closure resulted (Fig. I, D). The donor defect was closed by a split-thickness skin graft. Pectoralis major muscles have three segmental branches (sternocostal, clavicular, and external), which are defined by three independent neurovascular supplies (Fig. 3).2 The clavicular segment is supplied by the superior branch of the thoracoacromial vessels, the sternocostal segment is supplied by the inferior (pectoral) branch of the thoracoacromial vessels, and the external (abdominal) segment is supplied both by the lateral thoracic vessels and by lateral branches from the pectoral branch of the thoracoacromial vessels. The muscle can be surgically split between vascular
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Fig. 4. A, Closure of median sternotomy defect by bilateral split pectoralis major sternocostal segment muscle flaps (5) in a cadaver (with chest skin excised to show muscle-splitting technique). Clavicular (C) and external (E) muscle segments are left in situ to preserve donor motor function. B. Infected sternotomy wound dehiscence following coronary artery bypass procedure.
Fig. 4. Cont'd. C. Sternotomy defect closed with bilateral pectoralis major sternocostal segment advancement flaps (5). D. Primary wound healing, early hospital discharge, and preserved pectoralis muscle function resulted.
branches into these three segments, any of which can be transferred as a flap. We have used nine segmentally split pectoralis major myocutaneous or muscle flaps as follows: (l) chest wall reconstructions, (2) thoracoplasty and bronchopleuro-
cutaneous fistula closure, (3) closures of median sternotomy wound dehiscences (Fig. 4), (4) cover of exposed axillary vessels (Fig. 5), and (5) cover of an exposed saphenous vein graft to a segmental subclavian artery defect. We 2 • 4 previously reported application of
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Fig. 5. A. Rupture of bum scar contracture exposed axillary neurovascular structures (arrow). Split P. major sternocostal segment myocutaneous flap outlined. B. Result at 6 months. Myocutaneous flap allows a full range of shoulder motion. Clavicular and external muscle segments left in situ preserve donor motor function.
segmentally split pectoralis major flaps in other anatomic regions. CA SE 3. Closure of sternotomy dehiscence with pectoralis major muscle advancement flap created from sternocostal segment (Fig. 4). Wound infection and median sternotomy
dehiscence followed triple coronary artery bypass with saphenous vein in a 58-year-old man (Fig. 4, B). The wound was debrided and closed with bilateral muscle advancement flaps of the pectoralis major sternocostal segment (Fig. 4, C). Complete flap survival, primary healing, and mediastinal closure resulted (Fig. 4, D). Pectoralis major motor function was preserved by the clavicular and external muscle segments left in situ. CASE
4. Closure of axillary defect with split pectoralis
major myocutaneous transposition flap created from sternocostal segment (Fig. 5). Rupture of a severe burn scar
contracture of the right axilla exposed the axillary vessels and brachial plexus of a 45-year-old man (Fig. 5, A). The defect was closed with a 13 by 2I em mycutaneous transposition flap created from the sternocostal segment of the pectoralis major muscle. Complete flap survival, primary wound healing, and a full range of shoulder motion resulted (Fig. 5, B). Pectoralis major motor function was preserved by the clavicular and external muscle segments left in situ.
Extended fasciocutaneous flaps
Muscle-carried skin paddles may be extended well beyond the distal muscle borders by preserving vascular connections that extend to adjacent myocutaneous territories on the muscle fascia and in the overlying subcutaneous tissue. In the thorax, this flap refinement can be used to carry either abdominal or presternal skin on a pectoralis major muscle pedicle (Fig. 6).5-7 Rectus abdominis fascia and epigastric skin carried on pectoralis major fasciocutaneous flaps substantially lengthen the flaps and preserve breast position and substance (Fig. 7, C).5, 6 Presternal skin transferred on the pectoralis major muscle provides an alternative location for
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Fig. 6. Anatomic basis for extended P. major fasciocutaneous flaps. Left side (patient's right side): The pectoralis muscle carries an abdominal skin paddle (E) on rectus abdominus fascia (RF). Right side: A presternal skin paddle (P) also can be carried on the pectoralis major muscle.
a distal skin paddle but does not lengthen the flap substantially . 7 We used a pectoralis major fasciocutaneous flap extended onto the abdomen to reconstruct a precordial chest wall defect (Fig, 7). CAS E 5. Closure of chest wall defect with extended pectoralis major fasciocutaneous flap (Fig. 7). A 50-year-old
woman had recurrence of breast cancer I year after radical mastectomy on the left side and postoperative irradiation. Tumor excision required full-thickness removal of the precordial chest wall with exposure of the heart and lung (Fig. 7, A). The defect was stabilized with polypropylene mesh and covered with an epigastric skin paddle carried on the right pectoralis major muscle and rectus abdominis fascia (Fig. 7,
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Fig. 7. A. Chest wall resection for locally recurrent breast cancer. Exposed heart and lung covered with polypropylene mesh. B. Abdominal skin paddle (E) of extended pectoralis major fasciocutaneous flap outlined. C. Successful chest wall reconstruction. Note absence of breast displacement or disfigurement and primary closure of abdominal donor defect (arrow). B). Complete flap survival, primary wound healing, and tho-
racic closure resulted. Substance and position of the right breast were preserved (Fig. 7, C).
Reversed flaps
Both pectoralis major and latissimus dorsi flaps may be transferred on their caudal origins (reversed) because of secondary vascular supplies which are segmental, distal vascular pedicles, from internal mammary (to pectoralis major) and posterior intercostal (to
latissimus dorsi) vessels (Fig. 8).6. 8. 9 These secondary vascular pedicles will entirely support either flap when the primary vascular pedicles are interrupted. Reversed pectoralis major muscle flaps have been used to close median sternotomy wounds." However, we prefer to use split pectoralis major muscle advancement flaps developed from the sternocostal segment (Fig. 4) for sternal defects, because donor motor function is better preserved. Latissimus dorsi flaps can be reversed on posterior
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intercostal perforating vessels (Fig. 8).6,8 Usually, this maneuver is used to transpose the flap to flank, lumbar, or sacral defects. Reconstruction of a lateral thoracic defect with a reversed latissimus dorsi flap with its primary vascular pedicle destroyed by the original injury has been recently reported.!?
Island vascular pedicle muscle flaps Muscles may be converted to island vascular pedicle flaps that are transferred only on a single vascular pedicle (Fig. 9). This refinement can be used to permit flap transfer through intercostal incisions for closure of intrathoracic defects and cavities when intact muscle pedicles restrict transfer because of excess bulk or insufficient length. Well recently reported intrathoracic transfer of a rhomboid major muscle as an island vascular pedicle flap for successful repair of chronic esophagopleurocutaneous fistula (Fig. 9). Intrathoracic transfers of island vascular pedicle flaps are infrequently required, but this refinement can be valuable in specific instances. Intrathoracic transfer of latissimus dorsi myocutaneous flaps for repair of tracheoesophageal fistulas has also been recently reported.P
Clinical applications We have used the refinements of myocutaneous and muscle flaps described herein for successful reconstruction of complex thoracic and chest wall defects in 13 patients at the University of Louisville during the past 4 years. These applications include the following cases: (l) infected dehiscences of three median sternotomy incisions with exposure of saphenous vein grafts for coronary artery bypass, which were successfully closed with split pectoralis major muscle advancement flaps developed from the sternocostal segment (Fig. 4); (2) a simultaneous thoracoplasty and closure of a bronchopleurocutaneous fistula with a split pectoralis major muscle advancement flap developed from the sternocostal segment; (3) two massive chest wall defects, secondary to shotgun wounds, which were reconstructed with split latissimus dorsi (Fig. 2) and pectoralis major segmental flaps; (4) a precordial chest wall defect, secondary to resection of locally recurrent breast cancer, which was reconstructed with a pectoralis major fasciocutaneous extended flap (Fig. 7); (5) an exposed saphenous vein graft of the subclavian artery, which was covered with a split pectoralis major segmental muscle flap; (6) four wounds exposing axillary nerves and vessels, secondary to shotgun wounds or traumatically ruptured bum scar contractures, which were covered with segmentally split latissimus dorsi and pectoralis major myocutaneous flaps (Fig. 5); and
IP
Fig. 8. Anatomic basis for reversing latissimus dorsi flaps. Left side: Intercostal perforators (IP) provide a secondary vascular supply that supports the entire flap, or either of its segments. Right side: Skin peninsulas (P), or paddles, may be transferred on the reversed muscle, or its segments.
(7) a chronic esophagopleurocutaneous fistula, secondary to blunt trauma, which was closed by transfer of a rhomboid major muscle as an island vascular pedicle flap (Fig. 9).
Discussion Thoracic wounds present complex reconstructive challenges because of the following features: (l) Vital structures are often exposed. (2) Wound beds cannot be immobilized because of chest wall ventilatory excursion, pressure differences between the pleural cavity and atmosphere, and heart or great vessel pulsatile movement. (3) Flap access to cavitary defects and intrathoracic viscera is difficult because of the rib cage. (4) Exposed vein grafts are vulnerable to desiccation and rupture. (5) Bacterial contamination is frequently present. (6) Ischemic wounds frequently result from prior irradiation or scar deposition from chronic infection. Myocutaneous and muscle flaps are valuable in thoracic reconstruction because of their effectiveness and reliability in the presence of the anatomic and physiological challenges just described. The vigorous vascular supply of these flaps makes them our foremost reconstructive instrument for ischemic, contaminated, or poorly immobilized wounds. In the presence ofbacterial contamination, primary healing (rather than suppuration) is more common with these flaps than with skin flaps .13-15 The reliability of these flaps protects
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Fig. 9. A, Island vascular pedicle muscle flaps. Many muscles, or split muscle segmentsor myocutaneous units, can be transposed as islands on a single vascular pedicle. The rhomboid major (R), I. dorsi (LD), and P. major (PM) island flaps are shown here. B, Island vascular pedicle rhomboideus major muscle flap closure of an esophagopleurocutaneous fistula. The island muscle flap (R) is sutured over the esophageal defect. Successful esophageal repair and primary healing resulted. VP = vascular pedicle of the island rhomboid flap; E = esophagus; P = pericardium. vital structures and assures a continuing seal between pressure gradients. The size and bulk of these flaps address massive defects and intrathoracic cavities. These flaps provide a highly durable quality of cover. They allow options for immediate or elective secondary restoration of architectural stability and elimination of large flail regions.!" The flap refinements described herein preserve the virtues of myocutaneous and muscle flaps listed above and extend their reconstructive applications by increasing their versatility. Segmentally split flaps permit use of one muscle segment as a flap pedicle, with the other segments of the same muscle being left in situ to preserve donor motor function (Figs. 4 and 5).2, 3,17 Segmentally split flaps also allow use of a muscle segment as a flap when other segments of the same muscle are injured or destroyed (Fig. 2). Segmentally split flaps also permit reconstruction of two defects with independent branches of one flap." Extended fasciocutaneous flaps provide substantially longer and larger flaps (Figs. 6 and 7). These flaps also provide vascularized autogenous fascia for seal of pleural defects. In women, pectoralis major fasciocutaneous extended flaps avoid violating breast substance or position; the donor defect is located in the inframammary and epigastric areas (Fig. 7). Reversed pectoralis major and latissimus dorsi
flaps extend the field of coverage and allow use of these major muscle-skin units when their dominant vascular supplies are interrupted by the original injury or disease. 6, 8-10 Island vascular pedicle flaps provide flaps with small pedicles that can be passed through intercostal incisions for intrathoracic reconstructions when the muscle pedicle is too bulky or tethers the transfer (Fig. 9).11 This anatomic basis of flap refinement also allows free flap transfer and microvascular anastomoses for reconstructions in distant anatomic regions. Thus refinements of myocutaneous and muscle flaps substantially extend the versatility and application of these flaps for reconstruction of complex thoracic defects. REFERENCES Tobin GR, Schusterman MA, Peterson GY, Nichols G, Bland KI: The intramuscular neurovascular anatomy of the latissimus dorsi muscle. The basis for splitting the flap. Plast Reconstr Surg 67:637-641,1981 2 Tobin GR, Bland KI, Adcock R: Surgical anatomy of the pectoralis major muscle and neurovascular supply. Surg Forum 32:573-575, 1981 3 Tobin GR, MobergAW, DuBouR, WeinerU, Bland KI: The split latissimus dorsi flap. Ann Plast Surg 7:272-280, 1981
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4 Tobin GR, Spratt JS, Bland KI, Weiner LJ: One-stage pharyngoesophageal and oral mucocutaneous reconstruction with two segments of one musculocutaneous flap. Am J Surg 144:489-493, 1981 5 MaGee WP, McCraw lB, Horton CE, Mcinnis WD: Pectoralis "paddle" myocutaneous flaps. The workhorse of head and neck reconstruction. Am J Surg 140:507-513, 1980 6 MaGee WP, Gilbert DA, Mcinnis WD: Extended muscle and musculocutaneous flaps. Clin Plast Surg 7:57-70, 1980 7 Sharzer LA, Kalisman M, Silver CE, Strauch B: The parasternal paddle. A modification of the pectoralis major myocutaneous flap. Plast Reconstr Surg 67:753-762, 1981 8 Bostwick J, Scheflan M, Nahai F, Jurkiewicz MJ: The "reversed" latissimus dorsi muscle and musculocutaneous flaps. Anatomical and clinical consideration. Plast Reconstr Surg 65:395-399, 1980 9 Jurkiewicz MJ, Bostwick J, Hester TR, Bishop JB, Craver J: Infected median sternotomy wound. Ann Surg 191:738-744, 1980 10 Scheflan M, Bostwick J, Nahai F: Chest wall reconstruction. Manageme: of the difficult chest wound. Ann Plast Surg 8: 122-131, 1982 II Lucas AE, Snow NJ, Tobin GR, Flint LM Jr: Use of the rhomboid major muscle flap for esophageal repair. Ann Thorac Surg 33:619-623, 1982 12 Thesal BF, Clarke JS: Intrathoracic application of the latissimus dorsi musculocutaneous flap. Plast Reconstr Surg 66:842-845, 1980 13 Pappas C, Goldrick G, Cundy K, Wong W: Skin flaps vs. muscle flaps. Coping with infection in the presence of a foreign body. Plast Surg Forum 3: 133-135, 1980 14 Chang N, Mathes SJ: A comparison of the effect of bacterial inoculation on musculocutaneous and random pattern flaps. Plast Surg Forum 4:18-21,1981 15 Mathes SJ, Alpert BS, Chang N: Use of the muscle flap in chronic osteomyelitis. Experimental and clinical correlation. Plast Reconstr Surg 69:815-828, 1982 16 Arnold PG, Pairolero PC: Use of pectoralis major muscle flaps to repair defects of anterior chest wall. Plast Reconstr Surg 63:205-212, 1979 17 Tobin GR, Gordon JA, Smith B, Schusterman M: Preserving motor function by splitting muscle and myocutaneous pedicles. Plast Surg Forum 3: 160-161, 1980
Discussion DR. ROBERT W. JAMPLIS Palo Alto. Calif.
The advent of muscle and myocutaneous flaps has been one of the great advances in surgery in this past decade. Previously we were forced to use foreign material, such as Marlex mesh, or simply allow the defect to granulate in, with the many ensuing complications. I have had no personal experience with these flaps. It has been our policy for the surgeon to resect the lesion widely
227
without regard to reconstruction and then to have the plastic surgeon fill in the defect. I think that this is the correct way to manage these cases. Obviously, the authors, who are plastic surgeons, and their thoracic surgical colleagues in Louisville, must feel the same way. The realization that most of the skin's blood supply comes from the perforating vessels from the underlying muscles is what makes this all possible. As an aside, in 1906 an Italian named Tansini created the first myocutaneous latissimus dorsi flap to reconstruct a breast. It is a mystery to me how three generations can go by without the efficacy of this technique being recognized. I think it was probably due to the old Geheirnrat professors in those days, whose minds were closed to anything new. Fortunately, we do not have that problem anymore, at least in the United States. The authors did extensive dissection on cadavers to determine exactly the distribution and extent of the perforators. This information, unavailable in ordinary textbooks of anatomy, is the basis for all of these second-generation flaps. With this information, it should be possible to map out a viable flap accurately and predictably and therefore avoid the disaster of massive flap necrosis. This slide shows a malignant fibrohistiocytoma. It was given preoperative irradiation, and that is the extent of the dissection. One of my former interns, who is now a colleague at Stanford in the plastic surgery department, Bill. McClure, did this latissimus dorsi flap. This other case was an aneurysmal bone cyst which someone attempted to excise elsewhere. Terrible bleeding ensued, and the surgeon had to close and use external pressure for several hours to stop it. This was eventually excised, and a reverse pectoralis major flap was done. These operations were done without using second-generation flaps, which I think are the whole point of this presentation. By using them one can preserve the motor function of the muscle as well. Finally, I would like to ask the authors if they have had any experience in microneurovascular procedures, and what will their role be, if any, in the future?
DR. JOHN R. BENFIELD Los Angeles. Calif.
I would like to ask a question and make a comment. Myocutaneous flaps are very useful in oncologic operations for reconstructive purposes. My question is this: What has been the incidence of flap necrosis requiring revision? Are there newer techniques for assessing viability of the flap? The comment I would like to make has to do with the use of myocutaneous flaps for the management of chest wall tumors. I believe that an incisional biopsy specimen of these chest wall tumors should be obtained before extirpation and major reconstructive procedures are undertaken. It is, in general, necessary to get a permanent section carefully studied by the pathologist, perhaps even with electron microscopy, before major resections are undertaken. This allows one to assess precisely what the tumor is and to decide
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whether or not adjuvant therapy should be used. Then one can decide when to undertake the extirpation and reconstructive procedure, rather than to see the mountain and climb it immediately because it is there. DR. DONALD L. MORTON Los Angeles. Calif:
The Thoracic Surgical Oncology team, Drs. E. Carmack Holmes, Kenneth Ramming, and I, have resected about 20 massive chest wall tumors of this type. Treatment of these massive chest wall tumors requires wide resection of the lesion and, as Dr. Benfield said, a knowledge of the extent of tumor involvement before any resection is attempted. We treat many of these tumors preoperatively with intra-arterial chemotherapy and radiation. For stabilization of the chest wall, we still believe that Marlex mesh is most important for reconstruction of large defects. For example, we treated a patient with recurrent carcinoma of the breast who had received radiation to the operative site. The defect was very large. In the first step, Marlex mesh was used to stabilize the chest wall. I would emphasize that a monofilament suture material, such as nylon, should be used because this type of material will permit treatment of infection, should one occur, without necessitating removal of the mesh. Another time, we treated an extensive lymphangiosarcoma in the same way, except that an omental pedicle was created from the abdomen before skin was grafted over the wound. There are many ways to manage these large defects in terms of coverage if the thoracic surgical oncologist and his colleagues in plastic surgery use their combined ingenuity and creativity. DR. TO BIN (Closing) I thank each of the discussers for his comments. Dr. Jamplis, I certainly agree with the importance you place on accurate anatomic studies as a basis for reliable application of the flaps that are in our contemporary armamentarium. In Louisville, we do indeed have a large experience with microneurovascular reconstruction. Our experience in upper and lower extremity reconstructions is probably second to none. However, microvascular free flap reconstructions of the thorax are rarely required. This is due to the anatomic proximity of large thoracic muscle-skin units, such as latissimus
Thoracic and Cardiovascular Surgery
and pectoralis, and their long vascular pedicles, which reach virtually all thoracic defects. We would choose these regional pedicle flaps over free tissue transfers, unless compelling reasons were present in an individual case. Quantitative bacteriology is a useful adjunctive measure in clinical judgment on wound closure. We have learned that these flaps manage moderately contaminated wounds better than conventional flaps, although no flap in any circumstance is a substitute for adequate drainage, debridement, and local wound care. Wounds contaminated under 1050rganisms.per gram of tissue will often heal per primum when closed with a muscle or myocutaneous flap; by contrast, conventional skin flaps often fail to prevent suppuration at that level of contamination. Thus muscle flaps are valuable adjuncts in contaminated wound management, and quantitative bacteriology aids in their appropriate use. No flaps, however, prevent suppuration when contamination is greater than 105 to 106 organisms per gram of tissue, and no flaps cure established infection. I agree with the principles of chest wall tumor management, as stated by Drs. Benfield and Morton. These correspond to our practices in Louisville. Dr. Morton, the excellent outcome of your patient endorses the reconstruction selected. Alternatives are few for massive anterior midline defects. One or both pectoralis major myocutaneous units, extended by abdominal skin and fascia, are helpful in this location. Also, if internal mammary-superior epigastric vessels are intact (I suspect they were not in the patient you presented), we now know that one third (or more) of the abdominal skin can be carried on one rectus abdominis muscle to the chest. Dr. Benfield raised the question of flap viability and adjuncts that can help predict survival. Of course, these flaps do have an incidence of failure. Unquestionably, muscle and myocutaneous flaps are substantially more reliable than flaps of the past. However, we have substantially increased the complexity of tasks that we ask of them. Thus we extend them to their limits and occasionally pass beyond their limits. We use systemic intravenous Fluorescein with ultraviolet fluorescence evaluation to make intraoperative judgments on the limits of flap dimensions. To date, this has been our most reliable tool. Currently we are experimenting with other techniques of intraoperative definition of flap dimension, as flaps will surely always be extended to the limits of their capabilities.