Panniculectomy

Anatomy and Physiology

Men and women accumulate fat in distinct and predictable patterns. These patterns are genetically and hormonally determined. The fat distribution in men is primarily around the abdomen and torso, which is an android pattern. Women accumulate fat primarily around the hips and thighs in a gynoid pattern. 

The fat present in cellulite is no different from ordinary subcutaneous fat. The subcutaneous fat in the trunk area is composed of a superficial and deep layer. The superficial layer is dense and compact and contains multiple fibrous septa. The deep layer is loose, areolar, and contains few septa. The deep layers are located around the umbilical, gluteal, paralumbar, and medial thigh regions. One patient concern is the appearance of cellulite, which is the lay description for the external appearance of the superficial abdominal subcutaneous fat. This dimpling and ridging appearance is due to the presence of dense vertical septa of the subcutaneous ligamental attachments to the deep dermis, separating the fat into discreet pockets. As the fat hypertrophies or the skin relaxes with age, the septae cause an accordion-like irregular appearance known as cellulite.[4]

Fat cells are produced in utero, early childhood, and early adolescence. Once maturity is reached, the number of fat cells remains the same. When fat cells are removed through liposuction or other techniques, new fat cells do not form to replace them; however, the remaining fat cells may hypertrophy, causing the total fat mass in the area to increase or remain the same. One exception is in certain patients who are morbidly obese, wherein fat cells become hyperplastic and multiply in number.[5]

The primary blood supply to the abdominal skin is from the superior and inferior epigastric vessels. These vessels run within the rectus muscle and contain branching perforators that traverse the rectus fascia and abdominal fat, finally reaching the skin and subdermal plexus. When performing an abdominal flap, the blood supply is interrupted.

A second blood supply to the abdominal skin is located in the fat superficial to the fascia of Scarpa. The lateral intercostal, subcostal, and lumbar vessels are the only blood supply of the central abdominal skin after flap elevation. Previous surgeries in this superior and central abdominal area put the blood supply to the skin at risk because of interruptions of these vessels by prior surgical scars.[6]

The lower trunk has three horizontal zones of adherence: 1) the inguinal region, 2) the suprapubic region, and 3) the hip/lateral thighs. The tissue adherence becomes relaxed secondary to aging, pregnancy, and massive weight loss. Due to the laxity of these ligamentous attachments and senile changes of the overlying skin, the tissues descend vertically and concentrically around the pelvis and migrate centrally.[7][8]

Panniculectomy differs from an abdominoplasty in several ways. The amount of skin and adipose tissue undermining superior to the tissue being excised (panniculus) is extremely limited in panniculectomy. This is because the large abdominal flaps formed after massive weight loss often demonstrate a relatively compromised vascular status, owing to the increased distance of the skin from the vascular supply origin, essentially a watershed effect. Significant undermining in this situation is associated with a high rate of skin loss and seroma formation, both due to relative hypo-perfusion at the distal edges of the flap. The excision can almost be thought of as a wedge excision of the tissue to be removed. Previous scars must be carefully noted because these also predispose to tissue loss. If the tissue needed to be removed extends above the umbilicus, a umbilectomy is also discussed with the patient.[1][7]

Indications

The most common indication for panniculectomy is after the patient experienced a dramatic weight loss, with the resultant excess lower abdominal skin overhanging the groin and pubic regions. This is often seen in patients following bariatric surgery. The risk of formation of a large panniculus post-bariatric surgery is higher in older patients and patients with a higher pre-operative Body Mass Index.[9]

In severe cases, the panniculus can strike against the thighs as the patient walks, causing significant discomfort and irritation. This can severely limit patients' mobility and predispose them to refractory weight gain. Bariatric surgery patients typically achieve stable weight loss in 12 to 18 months, but some patients present in as few as six months for panniculectomy due to interference from the overhanging skin.

Contraindications

Panniculectomy is an elective procedure where medical problems must be well-controlled before considering the operation. Cigarette smoking affects blood supply and wound healing, and surgery should be avoided in active smokers and any patient with uncontrolled cardiac disease, lung disease, or diabetes. Any immunocompromised state is also a relative contraindication, owing to poorer wound healing.[10]

Patients with morbid obesity who are postbariatric have more severe deformities, excess skin, laxity, and poor tone. These patients are at greater risk of complications with medical comorbidities, surgical scars, and nutritional deficiencies.[7][11]

Equipment

A standard plastic surgery tray or large soft-tissue tray should be opened. In large-volume panniculectomy, a body-contouring retractor system may be employed. These systems consist of rigid tubular frames secured to the operative bed and provide a bar or ring above the patient from which massive panniculus can be suspended with specialized retractors or hooks to facilitate exposure and allow for the design of tension-free flaps and excision lines.[12]

Monopolar diathermy is essential, and bipolar cautery can also be useful for cauterizing smaller perforator vessels.

Personnel

This operation is typically performed under general anesthesia, induced and monitored by a qualified anesthetist.

The surgery is facilitated by an assistant, who can be another surgeon or other first-assistant-trained personnel. A scrub nurse or tech and a circulator/scout nurse are also required.

Preparation

Listening to the patient's chief complaint is essential, and determining mutual, realistic goals for the operation is paramount. Important questions to discuss are any history of constipation or difficulty in passing urine, clothing preference, dietary habits, exercise, and general activity level.

Focus special attention on the general length of the abdomen and the relationship of the costal margins to the iliac crest region. The lowest point of the costal margin to the iliac crests determines the waist configuration and potential for increasing definition at the waist. Patients with 5 to 6 cm waist configurations are considered short-waisted, while those with 10 to 11 cm configurations are long-waisted.[13]

The elasticity of the abdominal wall skin should be assessed. Photos should be obtained, and the patient should be cleared for surgery by the internist. It is vital to inform the patient about the risks of surgery, both medical/surgical as well as psychological, in terms of expectations and how any medical complications may affect said expectations. The patient should have realistic expectations about the procedure, and if there is any question in the mind of the medical, surgical, or anesthetic team, consultation with a psychiatrist pre-operatively is prudent.[14]

Technique or Treatment

An incision is made in the patient's natural suprapubic crease (often, this will be the inferior base fold of the panniculus). The incision is extended laterally towards the anterior superior iliac spine, stopping at the lateral edges of the pubic hair. The incision is deepened, and dissection is continued through the Scarpa fascia and down to the muscle.

Following the musculoaponeurotic fascial plan superiorly, the abdominal skin and subcutaneous tissue are excised. The wound is closed in multiple layers, with attention paid to the Scarpa fascia, deep dermis, and intradermal layers. Permanent or long-lasting absorbable sutures are used in these strength layers.

Avoiding dog ears on the lateral aspect when closing the wound is very important. Before the wound is closed, suction drains are placed under the flap and brought out through a small incision in the pubic region. Compression garments should be worn to prevent seroma formation while drains are present. Once the output of the drain is less than 30 mL/day, they can be removed, and compression garments can be continued for patient comfort.[13][15]

Complications

Postoperative complications are associated with comorbidities, higher pre-operative BMI, and previous bariatric surgery.[16]

Wound healing is the most common group of complications after a panniculectomy. This group of complications includes cellulitis, wound dehiscences, and tissue necrosis. The underlying pathophysiology is relative hypo-perfusion of the expanded abdominal tissue and flaps, as well as the overall poor blood supply of adipose tissue. Conservative management and wound care are usually the treatments of choice, but some patients require surgical intervention in the form of wound debridements or revision closures of dehiscent wounds, with tension-bearing sutures or closure devices occasionally required in severe dehiscences.[17]

Seromas are the single most common complication of panniculectomy, especially after a larger dissection. Once a flap is created, the body tries to fill the empty space with fluid, which is why suction drains are placed during the procedure in an attempt to evacuate fluid build-up in an ongoing fashion and facilitate the apposition of the dissected layers. This is also related to the relative hypo-perfusion of adipose tissue, both with blood vessels and lymphatics; both are significantly disrupted in panniculectomy. The best preventative management is the preservation of the Scarpa fascia with minimal dissection.[18] 

Postoperatively, compression garments and activity reduction can reduce seroma occurrence in select patients, particularly those with smaller-volume panniculectomy and lower overall BMI.[19] Once a seroma occurs, management involves close observation and serial aspirations. Some patients require catheter insertions or sclerosing agents.[20] When performing serial aspirations of seromas, there is a risk of introducing bacteria with each needle puncture. The practitioner must weigh the risks versus the benefits and ensure meticulous sterile technique before aspirating this hypo-vascular field to relieve a seroma. 

Simple cellulitis is a skin infection that responds to antibiotics and close follow-up. Complicated cellulitis is refractory to appropriate medical treatment and may result in abscess formation that could require surgical drainage and washout of the operative wound. Infected seromas are pseudo-abscesses and require intravenous antibiotics and surgical drainage. 

A hematoma is the accumulation of blood under the abdominal flap. Surgical drains placed during the operation do not prevent hematoma but allow the surgeon to track the amount and rate of postoperative bleeding to facilitate recognition of a hematoma early, hopefully, before the vascularity of the overlying flaps becomes compromised by an expanding blood collection. The drains may sufficiently evacuate a hematoma, particularly a low-volume and low-flow venous hematoma, and management in this situation is conservative. Surgical exploration is required to achieve hemostasis if the bleeding does not spontaneously stop, the hematoma is expanding, or the blood visualized in the drain is bright red.

Wound dehiscence is the premature separation of a wound which can occur at any level. Postoperatively, patients are instructed to remain bent at the waist 30 degrees in a semi-Fowler position for a week and thereafter to slowly return to the full upright position, often with the use of abdominal dressings or binders. The slow return to a standing position allows the wound to form scar tissue gradually, absorbing the mechanical loads of the over- and underlying tissues as the posture returns to upright, preventing the sutures from bearing the entire weight of the repair in an upright position, which can lead to failure and dehiscence.[18] Patients should be instructed about careful ambulation during the first few weeks postoperatively.[21]

Blood supply to the wound is essential for optimal wound healing. Vascular compromise can lead to tissue necrosis and wound breakdown. The relative hypo-vascularity of healthy abdominal adipose tissue layers has already been discussed, and this is compounded by surgical dissection into these hypovascular planes. Additional risk factors include extensive lateral dissection, excessive liposuction, thin flap, and extreme tension. Once skin necrosis occurs, local wound care is the treatment of choice to allow the wound to heal by secondary intention. After scar forms, discussion about scar revision is an option.[2][22]

Clinical Significance

Panniculectomy is not a cosmetic procedure. The intention of the procedure is to remove the excess skin and fat that hangs over the thigh and causes difficulty in personal hygiene, walking, and other physical activities. A panniculectomy must meet specific criteria to be medically necessary, and these criteria may vary by locale. The most commonly utilized criteria include the following:

1. The pannus must hang below the level of the pubis and be confirmed with photography.
2. Patients must fail medical treatment of intertrigo for three months. Medical treatment includes good hygiene, topical antifungals, corticosteroids, and antibiotics.
3. The role of panniculectomy is to restore normal function. Patients must maintain a stable weight for at least six months.
4. After bariatric surgery, patients must maintain a stable weight for at least 18 months, including the most recent six months.[1][13]

Enhancing Healthcare Team Outcomes

Whether surgical or medical, pannus treatment requires an interprofessional team involving a specialty-trained nurse and specialist surgeon. The primary care clinicians, as well as the nurse, should educate the patient about the procedure and encourage the patient to stop smoking. Since the surgery is elective, the patient should try and attain the desired body weight prior to surgery and must maintain this weight for a defined time period. All medical health problems should be assessed and minimized, and the patient's psychological health and overall expectations must also be maximized. Formal psychiatric evaluation is frequently recommended. The patient should be encouraged to remain physically active and to have completed and planned childbearing.

Patients require vigilant monitoring for extended periods, which entails close follow-up by both the clinician and nurse, with constant supervision and ongoing patient education. There should be close communication between the team members if one wants to achieve good outcomes. [Level 5]

Nursing, Allied Health, and Interprofessional Team Interventions

• Educate the patient about the procedure
• Obtain the consent
• Set up the surgery instruments
• Prepping the patient
• Assist the surgeon

Nursing, Allied Health, and Interprofessional Team Monitoring

• Monitor the patient during surgery
• Monitor the patient after surgery
• Speak to the family and relatives after surgery
• Follow-up after surgery