Chapter 55 Component Separation for Complex Abdominal Wall Reconstruction and Recurrent Ventral Hernia Repair

Brian Reuben, MD, Daniel Vargo, MD, Marga F. Massey, MD

INTRODUCTION

Since the 1980s, significant changes have occurred in the operative management of the abdomen in patients requiring large-volume resuscitation secondary to hemorrhagic or septic shock. “Damage control” laparotomies with rapid management of life-threatening conditions and temporary wound closure are increasingly more common and designed to avoid the dreaded triad of death—hypothermia, coagulopathy, and hemorrhage. In addition, intra-abdominal hypertension or “abdominal compartment syndrome” has become a well-recognized entity that often mandates management of a complex abdominal wall hernia with significant “loss of domain.” With damage control laparotomies and abdominal compartment syndrome, large abdominal wall defects are the resultant surgical challenge.

A mesh-independent technique of abdominal wall reconstruction was first introduced in 1990 to address large, complex abdominal wall hernias with either a prior history of infection or a significant loss of domain.¹ This autologous reconstruction method, commonly known as component separation, has achieved widespread acceptance for these types of problems before the introduction of the acellular dermal regenerative tissue matrix AlloDerm (LifeCell, Branchburg, NJ).^2,³ Component separation, as it was initially introduced, utilizes bilateral, innervated, bipedicle, rectus abdominis muscle and fascial composite flaps transposed medially to reconstruct the central abdominal wall. Several procedural variations have appeared in the literature, all based on central mobilization of the rectus abdominis muscle and associated overlying fascia and a distinct independence from synthetic mesh materials.³^–⁸

All effective methods of abdominal wall reconstruction address five basic goals: (1) restoration of function and integrity of the musculofascial abdominal wall; (2) prevention of visceral eventration; (3) provision of dynamic muscle support; (4) provision of a tension-free repair; and (5) optimizing an aesthetically acceptable appearance.^3,^4,⁹ Immediate reconstruction of a large abdominal wall defect is optimal. However, it may be suitable only in a medically stable patient with a clean wound bed and reliable reconstructive options that provide a tension-free closure. A delayed approach potentially involving multiple, staged surgical procedures is more common for the high-risk patient with an unstable or contaminated wound and multiple medical problems. Staged reconstructions commonly require the temporary use of absorbable mesh materials and delayed split-thickness skin grafting followed by a component separation procedure 6 to 12 months later. These extreme cases may require combined tissue expansion techniques to provide stable skin coverage over the fascial repair. They may require mesh in addition to a component separation procedure with the distinct goal of re-creating the majority of the abdominal wall with a tension-free predominance of innervated muscle flaps, which promote function (Fig. 55-1).

Figure 55-1 Staged abdominal wall reconstruction for abdominal compartment syndrome. A, A 56-year-old man with a history of necrotizing pancreatitis and abdominal compartment syndrome presented for a near-total abdominal wall reconstruction. His reconstruction was delayed secondary to a multiple laparotomy requirement for pancreatic débridement. Once he was medically stable, his open abdominal wound was managed by Vicryl mesh placement followed by dressing changes and progression to a Wound V.A.C. A staged split-thickness skin graft (STSG) was then placed at a second operative procedure. The patient had tissue expanders placed under his abdominal skin flaps to recruit skin for final skin flap closure as well as expanders beneath bilateral tensor fascia lata (TFL) flaps 12 months after his initial presentation. These expanders were filled weekly in preparation for his final reconstructive procedure. B, STSG and abdominal wall tissue expanders are removed at a delayed component separation procedure 15 months after his initial absorbable mesh placement. Bilateral “backup” expanded TFL flaps were not required to achieve a final closure. C, The patient is shown at 27 months after his initial presentation, 12 months after his definitive repair with midline approximation of his skin flaps as facilitated by abdominal wall tissue expansion. His fascia was reconstructed by a component separation procedure in addition to Prolene mesh, given the size of is fascial defect. Bilateral expanded TFL flaps, designed to supplement his component separation, were preserved, given an intraoperative finding of a 20-cm pancreatic pseudocyst requiring enteric diversion. It was believed that the patient was at risk for revisional intra-abdominal surgery, given his pancreatic pathology. At 1 year, he has no evidence of hernia recurrence, with a majority of his abdominal wound having been reconstructed by autologous, innervated rectus abdominis myocutaneous flaps.

Component separation is ideal for midline defects with fascial defects greater than 3 cm in transverse diameter.⁹ Bilateral component separation provides 8 to 10 cm of mobilization in the epigastric area, 10 to 15 cm in the midabdomen, and 6 to 8 cm in the suprapubic region.¹⁰ It is ideal for the high-risk, loss-of-domain patient who has failed a synthetic mesh repair secondary to infection. It is a significant reconstructive option for patients with stomas within the operative field. It should be considered superior and a first line of reconstruction for patients who have had prior irradiation, who have a bowel injury in the setting of a laparoscopic hernia repair attempt, who have suffered prior enterocutaneous fistula, or who have risk factors for wound healing problems that preclude the use of synthetic mesh materials. Coordinated preoperative evaluation by general and plastic surgeons with a focus on abdominal wall reconstruction is effective in the completion of these difficult surgical procedures with acceptable levels of morbidity and mortality.

INDICATIONS

• Large abdominal wall defect (>40 cm²)—loss-of-domain ventral hernia

• Epigastic (≤8–10 cm horizontal advancement requirement)

• Midabdominal (≤10–15 cm horizontal advancement requirement)

• Suprapubic (≤6–8 cm horizontal advancement requirement)

• Recurrence of hernia defect after prior primary closure attempt and contraindication for synthetic mesh

• Failed primary mesh hernia repair secondary to infection

• Bowel injury in setting of laparoscopic hernia repair

• Exposed mesh with unstable surrounding skin

• Presence of enterocutaneous fistula or ostomy in operative field

• Prior abdominal wall irradiation

OPERATIVE PROCEDURE

Skin Incision

Skin Necrosis and Dermal Dehiscence

Extreme care must be extended to patients with prior ostomies. Skin bridges between midline incisions and the ostomy site are at high risk for ischemia. If the ostomy is to remain, one should consider a unilateral component separation procedure (Fig. 55-3). If intestinal reconstruction is a part of the operative intervention, one should consider complete excision of the ostomy site including the intervening skin bridge (Fig. 55-4). If not feasible, typically in the thin patient, we recommend primary closure of the ostomy site with expectant management. Wound dehiscence at the previous ostomy site can be treated with dressing changes and staged closure at 5 days or wound V.A.C. management.

Figure 55-3 Unilateral component separation for maintained ostomy in the operative field. A, Intraoperative appearance of a 43-year-old woman treated for ovarian cancer to include a total colectomy and end ileostomy complicated by multiple small bowel fistulas–to–composite mesh placed to treat a prior midline evisceration event. B, No component separation is performed on the ipsilateral side of the end ileostomy in order to preserve ostomy function and to avoid possible parastomal hernia. C, Postoperative appearance at 6 months with no evidence of midline hernia and persistent good stoma function.

Figure 55-4 Adipocutanteous flap advancement and excision of prior colostomy site to promote wound healing. A, A 46-year-old woman with a history of rectal injury in the setting of open hysterectomy requiring diverting colostomy and open wound care, resulting in a midline hernia for repair. The patient has a prior Phanansteil incision concealed beneath her dependent pannus in addition to a right subcostal incision secondary to an open cholecystectomy. B, A midline incision was used for her exploration, given the patient’s prior right subcostal incision as a contraindication for an immediate transverse skin flap closure. Her transverse colostomy site was completely excised with medial advancement of her right-sided adipocutaneous flap to promote wound healing and improved abdominal wall contour.

Enter Peritoneal Cavity with Excision of STSG

Iatrogenic Enterotomy

• Consequence

Reentry into the peritoneal cavity of patients with complex hernias with or without STSG can potentially result in iatrogenic enterotomies with contamination of the surgical field. Such a complication can be limited to wound cellulitis. In its most extreme form, the patient may develop an enterocutaneous or enteroenteric fistula heralded by possible intra-abdominal abscess and sepsis.

Grade 1/2/3/4 complication

• Repair

Simple oversewing of the enterotomy with running 3-0 polydioxanone (PDS) suture is appropriate for minor serosal injuries. More extensive devascularization injuries should be approached with possible bowel resection using accepted stapling techniques.

• Prevention

Timing of exploration and STSG excision can be assessed on physical examination preoperatively. Typically, most patients are not ready for reoperation until the STSG can be lifted from the underlying bowel. Surgery should be delayed until this simple maneuver can be preformed in the clinic with minimal pain (Fig. 55-5). Patients without STSG should be delayed for a minimum of 6 months after they have achieved a closed wound.

Figure 55-5 Assessing time of elective hernia repair. Lifting the STSG from the underlying bowel should be a pain-free assessment in the clinic prior to elective hernia repair.

Meticulous sharp dissection during adhesiolysis using the surgical principles of traction and countertraction to develop dissection planes between loops of bowel and the abdominal fascia are necessary to prevent iatrogenic bowel injuries. Not all such injuries are preventable, particularly in patients with prior synthetic mesh placement. Judicious repair must be completed when injuries occur. We suggest aggressive staged irrigation of the abdomen and skin flaps during closure overtop of closed suction drains in the setting of iatrogenic bowel injuries.

Postoperative Ileus

• Consequence

A prolonged ileus is a common complication with a reported incidence of 27%.¹³ Uncomplicated ileus is the direct result of extensive enterolysis during the takedown of the hernia. It can be secondary to electrolyte abnormalities in patients having received a preoperative bowel preparation. Of more clinical concern, it can be an early sign of an intra-abdominal infectious process or intestinal anastomotic leak.

Grade 1/2/3/4 complication