Periumbilical Perforator Sparing Component Separation

1 Introduction

▴
Surgical site occurrences and surgical site infections (SSIs) are serious complications of ventral hernia repair. Both surgical site occurrences and SSIs are related to technical factors directly under the surgeon’s control.
▴
Component release hernia repair need not be associated with high rates of surgical site occurrences and SSIs, provided that the surgeon can maintain skin vascularity with perforator preservation and adequately distribute the forces of the closure to reduce suture pull-through.

2 Clinical Anatomy

▴
An angiosome is a block of tissue supplied by a single artery and vein. Human skin is vascularized by approximately 375 perforating blood vessels larger than 0.5 mm. Angiosomes come in different sizes, with a large vessel supplying a greater volume of tissue. Overlapping territories tend to show inverse size relationships, with a large perforator of one zone influencing a lack of development of an adjacent perforator.
▴
The territory of each angiosome is linked to the adjacent angiosome through “choke vessels” that open when necessary, such as with the interruption of the primary feeding vessel, and typically requires days to weeks to achieve maximal flow.
▴
The dominant blood supply to the abdominal wall comes from perforating blood vessels that emerge through the rectus abdominis muscle and supply the central abdominal skin. Below an imaginary line drawn just cephalad to the umbilicus, the source of these perforators is the deep inferior epigastric artery, and above the central rectus tendinous inscription, the source is the superior epigastric artery.
▴
In the inferolateral abdominal skin, the vascular supply is from the superficial inferior epigastric system. Over the external oblique muscles in the upper abdomen and mid-abdomen, lateral intercostal perforators are the source of perfusion. Abdominal skin flap elevation is a commonly performed surgical maneuver, but it is not without risk of tissue loss, as it requires adjacent angiosomes to supply the tissue whose primary perforating vessel is divided.
▴
The natural direction of blood flow in the abdominal wall parallels the dermatome lines from the umbilicus to the tip of either scapula.
▴
Old skin incisions interrupt the dermal circulation, and so one should assume that blood does not cross a scar. Therefore, it is preferable to re-incise an old skin scar and mobilize skin flaps rather than to create a new parallel incision. Prior skin flap elevation tends to “delay” the skin and to open choke vessels permanently.
▴
Pregnancy may act to increase the blood flow to the abdominal skin from its lateral sources. Pressure of the growing fetus on the inferior epigastric arteries limits total central blood flow. This phenomenon permits the plastic surgery abdominoplasty procedure to reliably elevate skin of most of the ventral abdomen in postpartum women.
▴
With new skin flap elevation and loss of a primary perforating vessel, the blood flow becomes less pulsatile and more laminar. Decreased total blood flow that lacks pulsatility has been shown experimentally and clinically to have more unreliable healing than when tissue is oxygenated with pulsatile blood flow.
▴
Scarred soft tissue vascular beds and undermined skin flaps have laminar flow and should be removed when possible at the time of incision closure.

3 Preoperative Considerations

▴
Repair of midline hernias re-establishes abdominal wall “core” pressure, improves local abdominal wall pain, and reduces the occurrence of hernia-associated bowel obstructions.
▴
Re-establishment of the linea alba requires that the abdominal wall musculature be pulled under tension to the midline. A reliable method of high-tension closures requires the distribution of forces at the suture/tissue interface (STI) to prevent suture pull-through.
▴
Patients must be evaluated for their ability to undergo a general anesthetic for several hours including the associated cardiac and pulmonary risks. The larger the hernia, the greater are the stresses experienced on the respiratory system.
▴
The standard anterior component release achieves decreased forces at the STI by division of the external oblique muscle and fascia from above the rib cage to the symphysis pubis. This maneuver also works to expand the abdominal domain and place less stress on the pulmonary system.
▴
All patients are encouraged to lose weight before surgery, but this is seldom achieved. Actively smoking patients similarly are urged to stop smoking for 2 months before the procedure, although smokers have not had worse outcomes for the procedure described in this chapter.
▴
Immunosuppressants are managed by the transplantation surgery teams. Steroids should be maintained at stable doses, and sirolimus should be avoided because of its profound effects on wound healing.
▴
The night before surgery, a gentle bowel preparation of clear liquids, a half bottle of magnesium citrate, and two bisacodyl tablets clears the bowel of particulate matter. This is done to decrease intra-abdominal volume and to minimize the early forces at the STI.

4 Anatomic Considerations

1 You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here