The separation of anatomic components technique for the reconstruction of massive midline abdominal wall defects: anatomy, surgical technique, applications, and limitations revisited

Reconstruction of massive abdominal wall defects has long been a vexing clinical problem. A landmark development for the autogenous tissue reconstruction of these difficult wounds was the introduction of "components of anatomic separation" technique by Ramirez et al. This method uses bilateral, innervated, bipedicle, rectus abdominis-transversus abdominis-internal oblique muscle flap complexes transposed medially to reconstruct the central abdominal wall. Enamored with this concept, this institution sought to define the limitations and complications and to quantify functional outcome with the use of this technique. During a 4-year period (July of 1991 to 1995), 22 patients underwent reconstruction of massive midline abdominal wounds. The defects varied in size from 6 to 14 cm in width and from 10 to 24 cm in height. Causes included removal of infected synthetic mesh material (n = 7), recurrent hernia (n = 4), removal of split-thickness skin graft and dense abdominal wall cicatrix (n = 4), parastomal hernia (n = 2), primary incisional hernia (n = 2), trauma/enteric sepsis (n = 2), and tumor resection (abdominal wall desmoid tumor involving the right rectus abdominis muscle) (n = 1). Twenty patients were treated with mobilization of both rectus abdominis muscles, and in two patients one muscle complex was used. The plane of "separation" was the interface between the external and internal oblique muscles. A quantitative dynamic assessment of the abdominal wall was performed in two patients by using a Cybex TEF machine, with analysis of truncal flexion strength being undertaken preoperatively and at 6 months after surgery. Patients achieved wound healing in all cases with one operation. Minor complications included superficial infection in two patients and a wound seroma in one. One patient developed a recurrent incisional hernia 8 months postoperatively. There was one postoperative death caused by multisystem organ failure. One patient required the addition of synthetic mesh to achieve abdominal closure. This case involved a thin patient whose defect exceeded 16 cm in width. There has been no clinically apparent muscle weakness in the abdomen over that present preoperatively. Analysis of preoperative and postoperative truncal force generation revealed a 40 percent increase in strength in the two patients tested on a Cybex machine. Reoperation was possible through the reconstructed abdominal wall in two patients without untoward sequela. This operation is an effective method for autogenous reconstruction of massive midline abdominal wall defects. It can be used either as a primary mode of defect closure or to treat the complications of trauma, surgery, or various diseases.     

Abdominal wall partitioning (the accordion effect) for reconstruction of major defects: a retrospective review of 10 patients

Ten patients underwent abdominal wall reconstruction using the technique of abdominal wall partitioning. All defects were closed in the midline by approximating fascia to fascia with the assistance of a general surgeon. One patient had skin grafted small bowel. Five patients had chronically infected mesh and previous failed attempts at repair. Four patients had large ventral hernias following gastric reduction operations and massive weight loss. No defect in any dimension was less than 20 cm. All patients had secure abdominal wall repair by reconstruction of a midline anchor for the abdominal wall musculature. One patient was lost to follow-up after 3 weeks. The average follow-up time for the remaining nine patients was 18.6 months (range, 6 months to 4.7 years). One patient required readmission to the hospital for management of a limited area of skin necrosis. Two patients had minor wound infections, and three patients had subcutaneous seromas, all of which were managed on an outpatient basis. One patient developed a 2 x 2-cm subxiphoid hernia recurrence. Technical details include subcutaneous undermining of the abdominal skin to the anterior axillary lines bilaterally, mobilization of the viscera to expose the white lines of Toldt bilaterally, and parallel, parasagittal, staggered releases of the transversalis fascia, transversalis muscle, external oblique fascia, external oblique muscle, and rectus fascia. These multiple releases allow expansion and translation of the abdominal wall by an accordion-like effect. This accordion-like effect allows closure of abdominal wall defects that are substantially larger than what can be closed with current techniques.     

Hyperbaric Oxygen in Therapy of Gas Gangrene—Report of a Case Following Induced Abortion

The treatment of gas gangrene has been revolutionized by oxygen drenching of tissues infected with Clostridia. This was used in a massive infection of the abdominal wall following a traumatic abortion attempt. The clostridial infection was controlled, but the patient almost succumbed to a secondary infection of gram-negative organisms. This responded to drainage, antibiotics and general supportive measures. In the course of treatment, the value of a team approach to complicated special problems was documented.     

Another indication for liposuction: small facial lipomas.

The treatment of facial lipomas at times requires the use of incisions that are less than satisfactory in either size or location. In an effort to minimize scarring, the authors have been removing these lesions with liposuction. The purpose of this study was to review the authors' experience in treating small facial lipomas using liposuction. Over the last 10 years, the authors treated five patients with forehead lipomas by removal with liposuction through hair-bearing scalp incisions. All patients were evaluated after the procedure for bleeding, paresthesias, recurrence, scarring, and overall satisfaction with the procedure. All of these patients had lipomas that measured 4 cm or less at the time of surgery. No patient experienced hematoma, nerve injury, or recurrence. All patients were completely satisfied with their result and scar. The literature describes an advantage to using liposuction for the treatment of medium (4 to 10 cm) and large (>10 cm) lipomas. Because small lipomas (<4 cm) can be extracted through small incisions, the literature reports no advantage to removal with liposuction. However, favorable aesthetic results can be obtained by removing small facial lipomas with liposuction through strategically placed incisions.     

Restoration of abdominal wall integrity as a salvage procedure in difficult recurrent abdominal wall hernias using a method of wide myofascial release

The management of primary and recurrent giant incisional hernias remains a complex and frustrating challenge even with multiple alloplastic and autogenous closure options. The purpose of this study was to develop a reconstructive technique of restoring abdominal wall integrity to a subcategory of patients, who have failed initial hernia therapy, by performing superior and lateral myofascial release. Over a 1.5-year period, 10 patients with previously unsuccessful treatment of abdominal wall hernias, using either primary repair or placement of synthetic material, were studied. The patients had either recurrence of the hernia or complications such as infections requiring removal of synthetic material. The hernias were not able to be treated with standard primary closure techniques or synthetic material. The average defect size was 19 x 9 cm. Each patient underwent wide lysis of bowel adhesions releasing the posterior abdominal wall fascia to the posterior axillary line, subcutaneous release of the anterior abdominal wall fascia to a similar level, and complete removal of any synthetic material (if present). The abdominal domain was reestablished by releasing the laterally retracted abdominal wall. The amount of available abdominal wall tissue was increased by wide release of the cephalic abdominal wall fascia overlying the costal margin and the external oblique fascia and muscle laterally. If needed, partial thickness of the internal oblique muscle and its anterior fascia were also released laterally to perform a tension-free primary closure of the defect. All repairs were closed with satisfactory functional and aesthetic results. All alloplastic material was removed. Fascial release was limited so as to close only the hernia defect without tension. No significant release of the rectus sheath and muscle was needed. Good, dynamic muscle function was noted postoperatively. All repairs have remained intact, and no further abdominal wall hernias have been noted on follow-up.     

Multiple symmetric lipomas with high levels of mtDNA with the tRNA(Lys) A-->G(8344) mutation as the only manifestation of disease in a carrier of myoclonus epilepsy and ragged-red fibers (MERRF) syndrome.

We have investigated the morphology, cytogenetics, and the fraction of mtDNA with the tRNA(Lys) A-->G(8344) mutation in three lipomas in a carrier of this mutation. The son of the patient had myoclonus epilepsy and ragged-red fibers syndrome. The fraction of mtDNA with the tRNA(Lys) mutation varied between 62% and 80% in cultured skin fibroblasts, lymphocytes, normal adipose tissue, and muscle. In the three lipomas the mean fraction of mutated mtDNA was 90%, 94%, and 94%. Ultrastructural examination of the lipomas revealed numerous mitochondria with changes such as electron-dense inclusions in some adipocytes. When considered cytogenetically, the lipomas were characterized by a mixture of karyotypically abnormal and normal cells. An identical del(6)(q24) was found in two tumors. The fraction of mutated mtDNA in cultured lipoma cells was the same as in the lipoma in situ, indicating that the cultured cells were representative of the primary tumor. These findings indicate that the lipomas have originated with a grossly normal stem line and subsequently have developed the 6q deletion. We conclude that the lipomas represent clonal growth of adipocytes with a high content of mtDNA with the tRNA(Lys) mutation. The tRNA(Lys) mutation may be either the direct or the indirect cause of pertubation of the maturation process of the adipocytes, leading to an increased risk of lipoma formation.     

Intraluminal thrombus and risk of rupture in patient specific abdominal aortic aneurysm - FSI modelling

Recent numerical studies of abdominal aortic aneurysm (AAA) suggest that intraluminal thrombus (ILT) may reduce the stress loading on the aneurysmal wall. Detailed fluid structure interaction (FSI) in the presence and absence of ILT may help predict AAA rupture risk better. Two patients, with varied AAA geometries and ILT structures, were studied and compared in detail. The patient specific 3D geometries were reconstructed from CT scans, and uncoupled FSI approach was applied. Complex flow trajectories within the AAA lumen indicated a viable mechanism for the formation and growth of the ILT. The resulting magnitude and location of the peak wall stresses was dependent on the shape of the AAA, and the ILT appeared to reduce wall stresses for both patients. Accordingly, the inclusion of ILT in stress analysis of AAA is of importance and would likely increase the accuracy of predicting AAA risk of rupture.     

Intraluminal thrombus and risk of rupture in patient specific abdominal aortic aneurysm – FSI modelling

Recent numerical studies of abdominal aortic aneurysm (AAA) suggest that intraluminal thrombus (ILT) may reduce the stress loading on the aneurysmal wall. Detailed fluid structure interaction (FSI) in the presence and absence of ILT may help predict AAA rupture risk better. Two patients, with varied AAA geometries and ILT structures, were studied and compared in detail. The patient specific 3D geometries were reconstructed from CT scans, and uncoupled FSI approach was applied. Complex flow trajectories within the AAA lumen indicated a viable mechanism for the formation and growth of the ILT. The resulting magnitude and location of the peak wall stresses was dependent on the shape of the AAA, and the ILT appeared to reduce wall stresses for both patients. Accordingly, the inclusion of ILT in stress analysis of AAA is of importance and would likely increase the accuracy of predicting AAA risk of rupture.     

The use of a subfascial vicryl mesh buttress to aid in the closure of massive ventral hernias following damage-control laparotomy

Damage control laparotomy for life-threatening abdominal conditions has gained wide acceptance in the management of exsanguinating trauma patients as well as septic patients with acute abdomen. Survivors considered too ill to undergo definitive abdominal wall closure are temporized, often with skin grafting on granulated viscera. These maneuvers compromise the integrity of the anterior abdominal wall and result in a subset of patients with loss of abdominal domain and massive, debilitating ventral hernias. A retrospective review was conducted of 21 such patients (16 men, five women) who underwent elective abdominal wall reconstruction at the Hospital of the University of Pennsylvania between November of 1998 and October of 2000. The purpose of this study was to report the authors' experience with these complex abdominal wall reconstructions. A double-layer, subfascial Vicryl mesh buttress was used in all repairs to aid in reestablishing abdominal wall integrity. The mean hernia size was 813 cm2 (range, 75 to 1836 cm2), and the average interval to definitive repair was 24.4 months (range, 3 weeks to 11 years). Mean follow-up was 13.5 months (range, 1 month to 40 months). Twenty patients (95 percent) had successful ventral hernia repair. Four patients with massive hernias (924 to 1836 cm2) required submuscular Marlex mesh implantation. Two patients (10 percent) developed abdominal compartment syndrome that required surgical decompression. One patient (5 percent) developed an incisional hernia at a prior colostomy site. Four patients (19 percent) had superficial skin dehiscence that healed secondarily with daily wound care. There were no mesh infections. In most cases, successful single-stage repair of large ventral hernias following damage control laparotomy can be achieved using a subfascial Vicryl mesh buttress in combination with other established reconstructive techniques. Massive defects exceeding 900 cm2 typically require permanent mesh implantation to achieve fascial closure and to minimize the risk of postoperative abdominal compartment syndrome and recurrent herniation. This technique represents an improved solution to a complicated problem and optimizes the aesthetic and functional outcome for these debilitated patients.     

Electron microscopic and radioautographic study of nucleic acid synthesis in normal fatty tissue and lipomas

Electron microscopic radioautography was used to study nucleic acid synthesis in the normal fatty tissue and lipomas of different degree of maturity. Destroyed adipocytes were found in the investigated varieties of the fatty tissue. In a slow-growing Madelung's lipoma such adipocytes occurred in a greater amount than in the normal fatty tissue and nongrowing lipomas. 3H-Thymidine was mainly incorporated by endotheliocytes and pericytes, whereas Madelung's lipoma contained a greater number of labeled cells. Based on the data obtained it is suggested that the replenishment of adipocytes occurs at the expense of the proliferation of vascular wall cells.     

An algorithm for abdominal wall reconstruction

Acquired abdominal wall defects result from trauma, previous surgery, infection, and tumor resection. The correction of complex defects is a challenge to both plastic and reconstructive and general surgeons. The anatomy of the abdominal wall, as well as considerations in patient assessment and surgical planning, are discussed. A simple classification of abdominal wall defects based on size, depth, and location is provided. Publications regarding the various abdominal reconstruction techniques are reviewed and summarized to familiarize the reader with the treatment options for each particular defect. Finally, an algorithm is presented to guide the surgeon in selecting the optimal reconstructive technique.     

Improving the Efficiency of Abdominal Aortic Aneurysm Wall Stress Computations

An abdominal aortic aneurysm is a pathological dilation of the abdominal aorta, which carries a high mortality rate if ruptured. The most commonly used surrogate marker of rupture risk is the maximal transverse diameter of the aneurysm. More recent studies suggest that wall stress from models of patient-specific aneurysm geometries extracted, for instance, from computed tomography images may be a more accurate predictor of rupture risk and an important factor in AAA size progression. However, quantification of wall stress is typically computationally intensive and time-consuming, mainly due to the nonlinear mechanical behavior of the abdominal aortic aneurysm walls. These difficulties have limited the potential of computational models in clinical practice. To facilitate computation of wall stresses, we propose to use a linear approach that ensures equilibrium of wall stresses in the aneurysms. This proposed linear model approach is easy to implement and eliminates the burden of nonlinear computations. To assess the accuracy of our proposed approach to compute wall stresses, results from idealized and patient-specific model simulations were compared to those obtained using conventional approaches and to those of a hypothetical, reference abdominal aortic aneurysm model. For the reference model, wall mechanical properties and the initial unloaded and unstressed configuration were assumed to be known, and the resulting wall stresses were used as reference for comparison. Our proposed linear approach accurately approximates wall stresses for varying model geometries and wall material properties. Our findings suggest that the proposed linear approach could be used as an effective, efficient, easy-to-use clinical tool to estimate patient-specific wall stresses.     

Primary Tumours of the Small Bowel and its Mesentery

Twenty-seven primary small bowel tumours encountered at the University of Alberta Hospital in a 10-year period have been reviewed. Seventeen symptomatic growths were treated by resection and 10 asymptomatic tumours were discovered incidentally. During this same period, three intramesenteric lipomas were found. Small bowel tumours were malignant in 15 of the 17 symptomatic cases and benign in seven of the nine asymptomatic cases. Carcinoid tumours, malignant lymphomas, non-lymphoid sarcomas and carcinomas were the common malignant neoplasms while adenomas, lipomas, myomas, fibromas and angiomas comprised the majority of benign growths reported. Symptoms of anorexia, anemia, abdominal pain, obstruction and hemorrhage suggest small bowel tumour if commoner pathology has been ruled out.     

Staged reconstruction after gunshot wounds to the abdomen.

Immediate closure of abdominal incisions after exploration and treatment of gunshot wounds is not always feasible or advisable. Significant bowel edema after massive fluid resuscitation might preclude primary closure, whereas any attempt to close under tension might result in complications ranging from wound dehiscence, infection, and necrosis to the abdominal compartment syndrome with abdominal, cardiopulmonary, and renal complications. For these difficult cases, the open technique has been recommended. The abdomen is left open and is closed when the patient's condition permits. When immediate wound approximation is not possible, temporary coverage can be achieved with a mesh, patch, or a split-thickness skin graft and the definitive reconstruction is deferred for a more optimal time. The purpose of this retrospective study is to report the authors' experience with staged abdominal wall reconstruction after gunshot wounds. From 1989 to 1998, 1933 patients underwent exploratory laparotomy for penetrating wounds to the abdomen. Twenty-nine patients in grave condition and with multiple medical problems were comanaged by the Trauma and Plastic Surgery Services at Cook County Hospital with the following protocol: The abdomen was initially left open and exposed viscera were covered with a variety of methods, including a Gore-Tex patch (W. L. Gore and Associates, Inc., Flagstaff, Ariz.). A split-thickness graft was subsequently placed on the granulation tissue over viscera at an average of 14 days after the last laparotomy. These planned ventral hernias were definitively treated at an average of 7 months after the skin grafting procedure, primarily using the components separation technique. In 24 patients, the fascia was closed primarily without tension, while five patients required the use of synthetic mesh to restore fascial continuity. Nine patients underwent closure of a colostomy or repair of fistulas simultaneously with abdominal wall reconstruction. One patient developed a postoperative hernia, two developed superficial wound dehiscence that healed without further surgery, and one required re-exploration for a failed anastomosis after colostomy closure. All but one patient maintained a stable abdominal wall after the reconstruction. The authors concluded that staged abdominal wall reconstruction should be primarily recommended for patients with complex abdominal wounds and a compromised general condition that precludes primary closure. With this treatment protocol, patients can recover faster from their trauma surgery and the risk of perioperative complications can be reduced. After final reconstruction, the continuity, stability, and strength of the abdominal wall are maintained in the vast majority of cases with the use of autogenous tissue and without the need for alloplastic material. With close cooperation between the trauma team and the plastic surgeon and appropriate timing and planning of each stage, the success rate of the technique is high and the incidence of complications limited.     

Elasticity of the living abdominal wall in laparoscopic surgery

Laparoscopic surgery requires inflation of the abdominal cavity and this offers a unique opportunity to measure the mechanical properties of the living abdominal wall. We used a motion analysis system to study the abdominal wall motion of 18 patients undergoing laparoscopic surgery, and found that the mean Young's modulus was 27.7+/-4.5 and 21.0+/-3.7 kPa for male and female, respectively. During inflation, the abdominal wall changed from a cylinder to a dome shape. The average expansion in the abdominal wall surface was 20%, and a working space of 1.27 x 10(-3)m(3) was created by expansion, reshaping of the abdominal wall and diaphragmatic movement. For the first time, the elasticity of human abdominal wall was obtained from the patients undergoing laparoscopic surgery, and a 3D simulation model of human abdominal wall has been developed to analyse the motion pattern in laparoscopic surgery. Based on this study, a mechanical abdominal wall lift and a surgical simulator for safe/ergonomic port placements are under development.     

Patient-specific initial wall stress in abdominal aortic aneurysms with a backward incremental method

Patient-specific wall stress simulations on abdominal aortic aneurysms may provide a better criterion for surgical intervention than the currently used maximum transverse diameter. In these simulations, it is common practice to compute the peak wall stress by applying the full systolic pressure directly on the aneurysm geometry as it appears in medical images. Since this approach does not account for the fact that the measured geometry is already experiencing a substantial load, it may lead to an incorrect systolic aneurysm shape. We have developed an approach to compute the wall stress on the true diastolic geometry at a given pressure with a backward incremental method. The method has been evaluated with a neo-Hookean material law for several simple test problems. The results show that the method can predict an unloaded configuration if the loaded geometry and the load applied are known. The effect of incorporating the initial diastolic stress has been assessed by using three patient-specific geometries acquired with cardiac triggered MR. The comparison shows that the commonly used approach leads to an unrealistically smooth systolic geometry and therefore provides an underestimation for the peak wall stress. Our backward incremental modelling approach overcomes these issues and provides a more plausible estimate for the systolic aneurysm volume and a significantly different estimate for the peak wall stress. When the approach is applied with a more complex material law which has been proposed specifically for abdominal aortic aneurysm similar effects are observed and the same conclusion can be drawn.     

Abdominal Lipomatosis with Secondary Self-Strangulation of Masses in an Adult Rhesus Macaque (Macaca mulatta)

An 10-y-old, intact male rhesus macaque (Macaca mulatta) presented for bilateral scrotal swelling and a distended abdomen. A soft mass in the left upper quadrant of the abdomen was palpated. A barium study did not reveal any gastrointestinal abnormalities. Exploratory laparotomy revealed a large (1.25 kg, 15.0 × 13.0 × 9.5 cm), red and tan, soft, circumscribed, spherical mass within the greater omentum and 10 to 20 smaller (diameter, 1 to 4 cm), soft to firm masses in the mesentery and greater omentum. The resected mass was a self-strangulating abdominal lipoma, a pedunculated neoplasm composed of white adipocytes arising from peritoneal adipose tissue undergoing secondary coagulation necrosis after strangulation of the blood supply due to twisting of the mass around the peduncle. The smaller masses were histologically consistent with simple or self-strangulating pedunculated abdominal lipomas. The macaque presented again 9 mo later with a firm, 5.0-cm mass in the midabdomen, with intestinal displacement visible on radiographs. Given this animal''s medical history and questionable prognosis, euthanasia was elected. Necropsy revealed numerous, multifocal to coalescing, 1.0- to 15.0-cm, pale tan to yellow, circumscribed, soft to firm, spherical to ellipsoid, pedunculated masses that were scattered throughout the mesentery, greater omentum, lesser omentum, and serosal surfaces of the gastrointestinal tract. All of the masses were pedunculated abdominal lipomas, and most demonstrated coagulation necrosis due to self-strangulation of the blood supply. To our knowledge, this report is the first to describe abdominal lipomatosis with secondary self-strangulation of masses in a rhesus macaque.Lipomas have been reported frequently in veterinary medicine as benign subcutaneous neoplasms in canines¹⁶ or as pedunculated peritoneal masses with the potential to cause intestinal strangulation in geriatric horses.⁶ Abdominal lipomatosis (multiple abdominal lipomas) in humans and dogs had been reported only rarely and have been accompanied by clinical signs of abdominal distention with or without secondary gastrointestinal complications.¹⁶ Lipomas of the skin of nonhuman primates have affected a patas monkey, an African green monkey, rhesus macaques, and chimpanzees. Lipomas within the peritoneal cavity have been diagnosed rarely in nonhuman primates. Reported cases include an omental lipoma in a mona monkey and an adrenal lipoma in a hamadryas baboon.¹⁴ Here we report the clinical signs, postmortem examination, and histopathologic features of abdominal lipomatosis in a rhesus macaque (Macaca mulatta).     

Sequence analysis of the MEN I gene in two patients with multiple cutaneous lipomas and endocrine tumors.

The discovery of mutations of the menin gene in a few multiple endocrine neoplasma type 1 (MEN I)-associated lipomas and loss of heterozygosity (LOH) on chromosome 11q13 in some sporadic lipomas has stimulated the hypothesis that lipomas may belong to the group of sporadic tumors caused by defects of the gene responsible for MEN I. Since it is unclear if the above hypothesis applies to all patients with lipoma or just to specific subsets, we searched to enlarge the database on this topic. For this purpose, we identified two patients with multiple cutaneous lipomas. One had an additional pituitary adenoma and familial presentation of multiple lipomas, the other had recurrent goiter in the setting of a family history of adenomatous goiter. Deoxyribonucleic acid (DNA) was analyzed by complete direct DNA sequencing of all coding exons and splice junctions of the MEN I gene. No mutation was identified in the coding exons of the menin gene. In contrast to former data on sporadic lipomas, these data are the first to render evidence that mutations of the MEN I gene may not be responsible for the formation of multiple lipomas, even if they appear in the context of other endocrine tumors.     

The midabdominal TRAM flap for breast reconstruction in morbidly obese patients

The transverse rectus abdominis myocutaneous (TRAM) flap is ideal for postmastectomy reconstruction but is tenuous in morbidly obese patients. Because of their relatively high incidence of postoperative complications, morbidly obese patients are often not considered candidates for autogenous reconstruction. The midabdominal TRAM flap has a more favorable anatomy and may represent an alternative technique in this patient population. The records of 18 morbidly obese patients who underwent postmastectomy reconstruction using a mid-abdominal TRAM flap from 1998 through 2002 were retrospectively reviewed. The mid-abdominal TRAM flap territory includes more of the supraumbilical region than the traditional TRAM flap, corresponding to an area with more abundant musculocutaneous perforators and greater dependence on the superior epigastric vascular system. All patients underwent unipedicled mid-abdominal TRAM flap surgery. Four patients with previous subumbilical midline incisions had a delay procedure with ligation of the inferior epigastric vessels. Complications investigated were flap necrosis greater than 10 percent or sufficient to require surgical revision, abdominal donor-site breakdown, seroma formation, umbilical necrosis, abdominal wall bulging or hernia, deep vein thrombosis, infected mesh, surgical revisions, fat necrosis, and extended hospital stay. At a mean follow-up time of 15.6 months (range, 12 to 24 months), three patients had postoperative complications requiring surgical revision. Two of these patients had previous midline abdominal incisions. One patient had both partial flap necrosis and a donor-site complication. The second patient had partial flap necrosis, and the third had an abdominal donor-site complication. No occurrences of abdominal wall hernia, total flap loss, deep vein thrombosis, infected mesh, extensive surgical revision, or extended hospitalization were noted in this series. The mid-abdominal TRAM flap represents an alternative method for postmastectomy breast reconstruction in morbidly obese patients. Autologous reconstruction using a midabdominal TRAM flap may be considered in this patient population; however, additional research is required to conclusively demonstrate an improved outcome when compared with traditional reconstructive methods.     

Uncoupling protein-1 mRNA expression in lipomas from patients bearing pathogenic mitochondrial DNA mutations

Multiple symmetric lipomatosis (MSL) is a rare disorder characterised by large subcutaneous fat masses in some parts of the trunk. Mitochondrial disfunction is common in MSL, but the identity of the adipose cells developing in multiple lipomas is not well known. We determined that brown adipose tissue-specific uncoupling protein-1 (UCP-1) mRNA is expressed in the lipoma of a multiple symmetric lipomatosis patient bearing the 8344 mutation in the tRNALys gene of mitochondrial DNA. UCP1 mRNA was not detected in normal subcutaneous fat from the same patient or in the lipoma of another patient bearing a different mutation in the same tRNALys gene. These findings implicate brown adipose cells as the origin of lipomas in a subset of patients bearing tRNALys mutations in mitochondrial DNA.