Chapter 10 Modified Minimally Invasive Component Separation 
1 Clinical Anatomy
One of the goals of minimally invasive component separation (MICS) is to avoid dissecting the subcutaneous tissue overlying the anterior rectus sheath and the vessels that penetrate the rectus abdominis muscle, thereby minimizing subcutaneous dead space and improving vascularity to the overlying skin. The inferior epigastric vessels penetrate the inferior lateral aspect of the rectus abdominis muscle and travel through the muscle, branching off into myocutaneous perforating vessels that provide vascular supply to the overlying abdominal skin and subcutaneous tissue.
2 Preoperative Considerations
Each patient’s risk for perioperative wound complications, infection, and hernia recurrence must be considered.
Realistic expectations of the potential outcomes must be clearly defined and discussed with each patient; topics should include the anticipated surgical outcome, possible complications, risk of recurrence, length of hospital stay, need for drainage catheters, and commitment to restrictions on activity.
2 Musculofascial Considerations
The surgeon must consider the size and location of the defect, particularly in difficult hernia repairs in the epigastric or low suprapubic area where the possibility of medializing musculofascial tissue is limited by a lack of tissue laxity. Previous surgeries and previously placed mesh materials that have failed also must be considered. Violation of the rectus complex with stomas, stomal site hernias, port site hernias, and/or indwelling catheters also must be considered but generally are not contraindications to MICS.
3 Intraperitoneal (Visceral) Considerations
Previous surgeries and/or intraperitoneal infections may increase intestinal and visceral adhesions, thereby complicating laparotomy and adhesion lysis before MICS.
4 Skin Considerations
The patient should be evaluated for sufficient availability and laxity of good-quality skin to ensure reliable cutaneous closure over the musculofascial repair. Sufficient closure must be achieved to reduce the risk of skin dehiscence after surgery.
5 Defect Considerations
Potential bacterial contamination, including infected mesh, contamination of the surgical field, inadvertent enterotomy, existing ostomy, and/or active open-wound infection, must be considered before MICS. To reduce the risk of infection, the surgeon should aggressively debride devitalized tissue, give perioperative therapeutic antibiotics, employ pulsatile lavage, reduce subcutaneous dead space, and drain subcutaneous space with closed-suction drainage catheters.
3 Operative Steps
After making a midline incision for laparotomy, the surgeon performs adhesion lysis to mobilize all the adhesions from the dorsal aspect of the abdominal wall. The surgeon incises the musculofascia exactly at the midline of the abdomen without violating the rectus complex. The surgeon then incises the midline defect superiorly and inferiorly to combine all areas of midline herniation into a single defect. In patients who have had previous surgeries, the surgeon should palpate intraperitoneally any areas of unopened midline incisions to identify sites possibly subject to future herniation. At this time, any planned or unplanned intraperitoneal or intrapelvic surgeries should be performed before MICS.
The surgeon dissects preperitoneal fat from the posterior sheath of the rectus abdominis muscle complex to facilitate the direct placement of implantable surgical mesh to the posterior rectus sheath. The majority of the preperitoneal fat pad is generally located in the central portion of the abdominal wall near the linea alba and is more extensive, thicker, and wider near the costal margin and the pubis than in the central, periumbilical area. Dissecting the preperitoneal fat pad flap at least 5 cm in the most cranial and caudal aspects of the defect facilitates mesh implantation. Patients with numerous previous surgeries and patients with a very thin body habitus may not have a well-defined preperitoneal fat layer. After adhesion lysis and preperitoneal flap dissection has been completed, the surgeon should place a moist, radiopaque-tagged towel or sponge on the intraperitoneal viscera to help protect it from inadvertent trauma and dissection.
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