Abdominal fat harvest technique and its uses inmaxillofacial surgery

Dennis J. Kantanen, DDS," James J. Closmann, DDS,b and Henry H. Rowshan, DDS,'Honolulu, HawaiiDIVISION OF ORAL AND MAXILLOFACIAL SURGERY, TRIPLER AR~IY MEDICAL CENTER

Abdominal fat harvest and augmentation to the maxillofacial region is a relatively inexpensive, safe, andreadily available procedure. The use of abdominal fat free transfer has been well documented for cosmetic, trauma,and temporomandibular joint reconstruction. Fat is the closest we have to an ideal filler, it is readily available andinexpensive, it is autologous and therefore lacks a host immune response, it is safe and noncarcinogenic, and it iseasily acquired with a minimally invasive procedure. Abdominal fat donor site is the most commonly used owing toease of access and availability of fat stores. Complications are rare and easily managed in the office. Free abdominalfat harvest is a predictable surgical technique that allows the maxillofacial surgeon access to autologous graft materialthat is ideal for multiple facial procedures. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;109:367-371)

Abdominal fat harvest and augmentation to the maxil­lofacial region is a relatively inexpensive, safe, andreadily available procedure.' The use of abdominal fatfree transfer has been well docnmented for cosmetic,trauma, and temporomandibular joint reconstruction. In2009, autogenous fat is still the preferred method forthe treatment of frontal sinus obliteration. Abdominalfat has been nsed since the 1890s for cosmetic proce­dures 2 En bloc resection and removal of abdominal fathas been shown experimentally to contain a greaterpercentage of surviving adipocytes compared with can­nnla removal. 3 Therefore, the aim of the present articleis to discuss the suprapubic abdominal fat harvest tech­nique to include the pertinent anatomy, complications,and uses of the technique.

ABDOMINAL FATThere are a myriad of autogenous and alloplastic

materials that can be used for maxillofacial proceduresfor trauma, cosmetic, facial, and temporomandibularjoint (TMJ) reconstruction. Facial rejuvenation withautologous fat has the advantage of replacing or aug­menting tissue with like tissue. Over the past 10-15

The views and opinions expressed herein are those of the authors anddo not necessarily reflect those of the Department of the Defense orthe Department of the Army.aChief resident, Division of Oral & Maxillofacial Surgery.bChief and Program Director, Division of Oral & MaxillofacialSurgery.CAssistant Program Director, Division of Oral & MaxillofacialSurgery.Received for publication May 5, 2009; accepted for publication Sep8,2009.1079-2104/$ - see front matterPublished by Mosby, Inc.doi: 10.1016/j .tripleo.2oo9.09.037

years, more widespread clinical use of autologous fatgrafts for facial soft-tissue augmentation suggests thatthis procedure is the best presently available. In manyways, fat is the closest we have to an ideal filler: It isreadily available and inexpensive, it is autologous andtherefore lacks a host immune response, it is safe andnoncarcinogenic, and it is easily acquired with a min­imally invasive procedure. Viable autogenous free ab­dominal fat along with the removal of mucosal liningfrom the frontal sinus consistently prevents regrowth ofthe mucoperiosteum. The use of autogenous fat forfrontal sinus obliteration purposes continues to be thegold standard (Fig. 1).4-6 Areas of the maxillofacialregion that are routinely augmented during cosmeticprocedures include the malar region, lips, nasolabialfolds, and mental area. Facial reconstruction for thetreatment of facial lipodystrophy due to underlyingHIV disease has been documented (Fig. 2).7 Free ab­dominal fat has been used dnring the treatment of TMJdisorders (Fig. 3). During open joint surgery, free ab­dominal fat has been transplanted into the joint space toreplace joint space after complete removal of the discand associated capsule. The use of autologous fat graftsin the treatment of TMJ ankylosis has been reported inthe literature as early as 19138

•9 Autologous transplan­

tation of abdominal fat around the TMJ can minimizeoccurrence of fibrosis and heterotopic bone formation,leading to improved range of motion.'o Autologonstransplantation of fat has been used as a method toprevent heterotopic bone formation after hip replace­ment surgery for many years.'o The use of dermal fatfor correction of contour defects in the head and neckarea from trauma, congenital defects, and neoplasm hasremained a well known and time-honored choice (Fig.4)7 Dennafat is used owing to the dennal layer being

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Fig. 1. Frontal sinus obliteration with autologous abdominalfat.

Fig. 2. Free abdominal dennafat graft for treatment of HIV­associated lipodystrophy syndrome. From Rowshan et a1.7

the vasoinductive layer for the underlying adipose graftand is nsually placed facing against the subadjacentsubcutaneous layer for optimal blood supply.

TECHNIQUE OF AUTOGENOUS FREEABDOMINAL FAT HARVEST

Extensive comparative studies between different do­nor sites and fat graft success have yet to be conducted.The abdominal donor site is the most common owing toease of access and availability of fat stores. Generalanatomic knowledge of the anterior abdominal wall iscritical for abdominal fat harvest (Fig. 5). The anteriorabdominal wall in the suprapubic area consists of 7layers:

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Fig. 3. Free abdominal fat graft used in temporomandibularjoint reconstruction. Courtesy of Michael Doherty, DDS.

Fig. 4. Free abdominal derrnafat used during superficial pa­rotidectomy to prevent Frey syndrome and to fill the cosmeticdefect. Courtesy of Henry H. Rowshan, DDS.

I. Superficial skin.2. Subcutaneous fat.3. Superficial fascia.4. Deep fascia.S. Rectus abdominis muscle.6. Subserous fascia.7. Peritoneum.

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Fig. 5. Anatomy of anterior abdominal wall in umbilicusregion.

The subcutaneous fat layer can be accessed rathereasily immediately below the superficial skin and sub­cutaneous tissue, which normally measures 5-10 mmdeep. Depending on the size of the patient, a sufficientlayer of subcutaneous fat can be obtained without dif­ficulty. Below the subcutaneous fat, the superficial anddeep fascias are encountered. The superficial fasciaoverlies the entire anterior abdominal wall just belowthe abdominal fat. The deep fascia surrounds the ab­dominal rectus muscles. The deep fascia of the abdom­inal wall is different than that found around muscles ofthe extremities. It is of the loose connective tissuevariety. It is necessary in the abdominal wall because itoffers more flexibility for a variety of functions of theabdomen. At certain points, this fascia may becomeaponeurotic and serve as attachments for muscle andbone, as for the linea alba. The rectus abdominis muscleis a paired muscle running vertically on each side of theanterior abdominal wall. The muscle is a key posturalmuscle, responsible for flexing the lumbar spine. Sub­serous fascia, also known at extraperitoneal fascia, is alayer of loose connective tissue that serves as a glue tohold the peritoneum to the deep fascia of the abdominalwall or to the outer lining of the gastrointestinal tract. Itmay receive different names depending on its location(i.e., transversalis fascia when it is below that muscle,psoas fascia when it is next to that muscle, iliac fascia,etc.) Lastly, before entering the abdominal cavity, theperitoneum, a thin I-ceIl-thick membrane that lines theabdominal cavity and in certain places reflects inwardto form a double layer of peritoneum. Double layers ofperitoneum are called mesenteries, omenta, falciformligaments, lienorenal ligament, etc.

The following surgical technique is currently used atthe our institution for fat harvest. The free abdominalfat graft harvest begins by first outlining a 3-5 cmtransverse midline incision line approximately 2-3 cmbelow the umbilicus (Fig. 6). One-percent lidocainewith I: 100,000 epinephrine is injected into the pro­posed surgical site. A #10 blade is used to make an

Kantanen et ai. 369

Fig. 6. 3-5 cm transverse midline incision approximately 2-3cm below the umbilicus.

Fig. 7. Two Kocher clamps aiding in fat harvest.

incision through skin and subcutaneous tissue to exposethe abdominal fat pad. Electrocautery is then used tocontrol and obtain surgical site hemostasis. Two Kocherclamps are placed on the superficial subcutaneous fat toapply tension to aid in the fat harvest (Fig. 7). Care istaken to limit the dissection to superficial of the ab­dominal muscular fascia. During the harvesting, theoverlying skin is undermined to maximize the abdom­inal fat harvest and minimize the length of the skin

370 Kantanen et ai.

Fig. 8. En bloc fat harvest.

incision. A 3-5 mm layer of fat on the skin side ismaintained to decrease the likelihood of an uncosmeticresult and wound dehiscence. With adequate tension onthe fat graft, the fat is then widely undermined super­ficial to the rectus abdominis muscle fascia to a similarextent as the overlying skin dissection. The desiredamount of graft is harvested from the midline region(Fig. 8). To allow for shrinkage and errors in frontalsinus volume estimation, the fat harvest should be-30% more than the estimated amount needed to fillthe dead space of the frontal sinus or whereever it is tobe used. Before closure, meticulous hemostatis isachieved with electrocautery and the need for a drain isnot indicated. The dissection should not violate theabdominal muscular fascia and should remain solely inthe underlying fat layers. The wound is closed byadvancing the superior and inferior fat flaps toward thesurgical incision and sutured with 3-0 vicryl popoffs inan interrupted fashion. The subcutaneous tissue isclosed with 4-0 monocryl in a subcuticular closurefashion (Fig. 9). To minintize the incidence of hema­toma and seroma formation, a pressure dressing ofKerlix (Hamilton Medical Products, Mill Valley, CAlfluffed gauze and elastic tape is applied and maintainedfor a period of 3 days before removal. The harvestedautogenous free abdominal fat is wrapped in a moistsaline gauze sponge (Fig. 10). Metabolic analysis hasshown improved cell viability in fat tissue specimensundergoing ntinimal manipulation. II Once the maxillo­facial graft site is accessed and prepared, the en bloc

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Fig. 9. Final closure of abdominal fat harvest site.

Fig. 10. Fat wrapped in gauze sponge.

autologous fat can be placed into the prepared area.Patients are maintained on appropriate antibiotics, typ­ically cephalexin, 500 mg 4 times a day for 7 days, aswell as analgesics after surgery.

COMPLICATIONSAlthough fat transfer is generally regarded to be a

safe procedure, there are reports of associated morbid­ity. Possible complications of abdominal fat graft har-

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vest include seroma, infection, hematoma, ileus, andinadvertent peritoneal perforation. The most commoncomplication, although still rare, is a seroma formationat the abdominal fat harvest site. Wolford et al. 12 re­ported a 6.9% incidence of seroma fonnation requiringaspiration. Postsurgical abdominal seromas are typi­cally evacuated with percutaneous drainage and aspi­ration under local anesthesia. Infection rates are con­sistent with any other surgical procedure, with anincidence of around 3%. J2 Abdominal subcutaneoushematoma formation is a rare occurrence during ab­dominal fat harvest, with a reported incidence between0% and 3.2%, owing to the small surgical field, shortsurgical time, and ease to obtain hemostatis. J3 Withcareful attention to hemostasis, drain placement into theharvest site is rarely needed. Adequate placement offluffed gauze and elastic dressing minimizes the inci­dence of hematoma formation. Postsurgical ileus andinadvertent peritoneal perforation are possible sequelaeduring abdominal fat harvest. An ileus occurs fromhypomotility of the gastrointestinal tract in the absenceof a mechanical bowel obstruction. Frequently, an ileusoccurs after intraperitoneal operations, but it may alsooccur after retroperitoneal and extra-abdominal sur­gery. No documented cases of postsurgical ileus orperitoneal perforation after abdominal fat harvest couldbe found in the literature.

Kaufman et al.\" found that fat transfered into sub­cutaneous tissue demonstrated 30% survival after 6months. Keerl et al. \5 studied fat implanted into thefrontal sinus of 11 patients for obliteration of the frontalsinus cavity. Postoperative magnetic resonance imag­ing evaluation showed viable fat in 6 of the II patients4-24 months after surgery. In the remaining 5 patients,the fat demonstrated necrosis and had been replaced bygranulation tissue and connective tissue.

CONCLUSIONFree abdominal fat harvest is a predictable surgical

technique that allows the maxillofacial surgeon accessto autologous graft material which is ideal for multiplefacial procedures. Minimal morbidity and ideal graftmaterial will enable abdominal fat to continue to be thegold standard upon which all filler materials are com­pared.

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Dr. Dennis J. KantanenTripier Army Medical Center1 Jarrett White RoadHonolulu. Hawaii 96859-5000dkaOlanen@hotmail.com