Periumbilical Perforator Sparing Component Separation

Transcription

1 CHAPTER 9 Periumbilical Perforator Sparing Component Separation Gregory A. Dumanian, MD 1. Introduction s 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. s 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 s 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. s 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. s 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. s 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, 166

2 Chapter 9 Periumbilical Perforator Sparing Component Separation 167 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. s The natural direction of blood flow in the abdominal wall parallels the dermatome lines from the umbilicus to the tip of either scapula. s 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. s 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. s 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. s 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 s Repair of midline hernias re-establishes abdominal wall core pressure, improves local abdominal wall pain, and reduces the occurrence of hernia-associated bowel obstructions. s 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. s 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. s 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. s 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. s 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. s 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.

3 168 Section IV Component Separation 4. Anatomic Considerations 1. Skin Vascularity s If skin perforators are preserved during the procedure, the skin will maintain its pulsatile flow. Therefore avoidance of wide skin undermining is a critical component of component separation hernia repair. s Skin vascularity and the status of periumbilical perforators can be ascertained with knowledge of prior operations by reading old operative reports. s Although avoidance of smoking is important for overall health, avoidance of postoperative coughing and pneumonias, and wound healing, it is not a contraindication for surgery. Maintenance of skin pulsatile blood flow is equally or even more important to meaningfully lower SSI rates. s Scarred tissue and wounds have nonpulsatile blood flow and should be excised. 2. Force Distribution s Force distribution is a concept that focuses on reducing the forces experienced at each STI. The lower the STI at each suture and the more evenly distributed the forces for closure, the higher the success of closure. s The total force of closure is divided by the total number of sutures, lowering the force at each individual site and decreasing suture pull-through. s The initial strength of the construct is achieved with a narrow mesh quilted to both rectus muscles. With mesh incorporation and biologic healing of the reconstructed linea alba, the total strength of the repair increases, and the stresses experienced at the STI decrease. s A compliant abdominal wall absorbs energy with coughs, Valsalva maneuver, and forceful movements rather than sending energy waves to the STI that can cause ripping and failure of the hernia construct. s Patients with weight loss, treated ascites, and a history of multiple large gestations are known to have compliant abdominal walls and relative success with closure. s Patients with noncompliant abdominal walls include patients with prior intra-abdominal sepsis and scarring, long-standing hernia history, prior repairs, radiation to the abdominal wall, lateral scarring from prior incisions, and obesity (Fig. 9.1). s The release of the external oblique muscle is a means to improve lateral abdominal wall compliance and protect the STI from pull-through. s The best hernia repairs have smooth transitions between repaired abdominal wall and intact fascia, with a matching of compliances. Mismatched compliances cause high tension at the STI and suture pull-through. s Anchoring mesh to noncompliant rib or symphysis pubis in particular leads to areas of imbalance of STI forces and early failure. It should be avoided when possible and does not lead to a stronger repair. s Compliance mismatches (and increased chance for failure) exist when a direct supported repair for a midline incisional hernia ends adjacent to significant rectus diastasis. s A longer repair with properly balanced forces at each STI (working out the dog-ears of the abdominal closure) is optimal for long-term success and is preferable to a short repair.

4 Chapter 9 Periumbilical Perforator Sparing Component Separation 169 A Fig. 9.1 B

5 170 Section IV Component Separation 5. Operative Steps 1. Skin Incision and Clearing Hernia Sac and Posterior Aspect of Abdominal Wall s With the patient under general anesthesia, a skin incision longer than the prior scar is made (Fig. 9.2). s Many surgeons advocate for additional epidural anesthesia to blunt the systemic inflammatory response. s Adhesions to the hernia sac and the posterior aspect of the abdominal wall are widely taken down (Fig. 9.3). If possible, enterolysis is avoided to lessen postoperative visceral swelling and forces on the STI. 2. Readying Rectus Muscles for Closure s The anterior rectus fascia is cleared a distance of 4 cm from its medial border by incising the hernia sac. This maneuver will not interrupt any lateral rectus perforators, and it will not reach the semilunar line. The hernia sac will be excised at the end of the procedure. s For patients with normal abdominal wall compliance based on history and physical examination, a hernia in which the medial aspect of the rectus muscles is separated by less than 6 cm on computed tomography scan can be closed with a direct supported repair using a retrorectus mesh and without a component release. s For a hernia with a separation of the medial aspect of the rectus muscles between 6 and 12 cm, a component separation is usually needed to achieve a direct supported repair with a retrorectus mesh. s For a hernia in which the medial aspect of the rectus muscles is separated by more than 12 cm, I typically use a component release with an intra-abdominal mesh to achieve fascial closure. 3. Anterior Component Release With Perforator Preservation s To perform a component release and maintain skin vascularity, a transverse incision about 6-8 cm in length is made at the inferior aspect of the rib cage (Fig. 9.4). s The end of the external oblique muscle is visualized as it becomes the anterior rectus fascia (Fig. 9.5). s Blunt dissection using the end of a narrow Deaver retractor superiorly onto the chest and inferiorly in the direction of the anterior superior iliac spine (ASIS) is performed to expose the semilunar lines (Fig. 9.6). s The entire external oblique muscle and fascia is divided with cautery to create a myofascial rectus abdominis flap. It is important to release high onto the ribs to take tension off of the superiormost rectus muscle during closure and to the level of the ASIS (Fig. 9.7). s An unnamed fascia on the undersurface of the external oblique muscle should also be divided.

6 Chapter 9 Periumbilical Perforator Sparing Component Separation 171 Fig. 9.2 Fig. 9.3 Fig. 9.4

7 172 Section IV Component Separation A B Fig. 9.5 A B Fig. 9.6

8 Chapter 9 Periumbilical Perforator Sparing Component Separation 173 Superior tunnel created by blunt dissection with a narrow Deaver retractor External oblique muscle and fascial division, high on ribs Internal oblique muscle B 6-8 cm 6-8 cm A External oblique myofascial division carried to ASIS C Fig. 9.7

9 174 Section IV Component Separation 4. Completion of Inferior Release With Suprapubic Tunnel s A blunt tunnel is created from the lower aspect of the midline incision in the suprapubic area toward the ASIS and is brought into continuity with the tunnel created from the upper lateral incision. The cut end of the external oblique muscle, in the shape of the letter V, is captured by a dissecting index finger and pulled into the midline incision, where it is divided under direct vision (Fig. 9.8). The direction of the release should be toward the groin; division of the anterior rectus fascia itself must be avoided (Video 9.1). s Through the transverse incision, the external oblique is bluntly elevated off of the internal oblique to improve abdominal compliance and to allow for medial movement of the rectus abdominis muscle. s For very obese patients in whom elevation of the suprapubic tissue can be problematic, a second short transverse incision near the ASIS can be made for the completion release of the external oblique toward the symphysis pubis. s Perforators are not individually skeletonized, simplifying and speeding up the release, which takes about 4-5 minutes on each side to perform. 5. Mesh Placement With Force Distribution s This procedure uses a narrow, extremely well-fixed mesh, in contradistinction to the standard approach for mesh placement of wide overlap and minimal fixation. A narrow mesh facilitates placement of fixation sutures under direct vision but with limited skin flap elevation. s When a retrorectus mesh is placed, the space between the posterior fascia and the rectus muscle is opened for about 4 cm, avoiding the deep inferior epigastric artery, perforators to the posterior fascia, and lateral intercostal segmental nerves. s The posterior fascia is closed with a running 2-0 monofilament absorbable suture to exclude the bowel (Fig. 9.9).

10 Chapter 9 Periumbilical Perforator Sparing Component Separation 175 ASIS V shaped cut end of external oblique muscle hooked with dissecting finger A Fig. 9.8 Horizontal, suprapubic blunt tunnel created to meet vertical tunnel B External oblique pulled into midline incision and divided under direct vision and toward groin A Fig. 9.9 B

11 176 Section IV Component Separation s A 7.5-cm-wide piece of macroporous medium-weight monofilament uncoated polypropylene is oriented so that tension applied onto the mesh for the midline closure keeps the pores large and open (Fig. 9.10). s A wider mesh would require greater soft tissue elevation, a change in lateral abdominal wall compliance, and increased difficulty with fixation. Wider meshes have greater wrinkles at their borders because of the inability to fit a flat mesh to a curved surface. Wider meshes by definition have more foreign material, change a greater percentage of abdominal wall compliance, and are unnecessary. s 0-Polypropylene sutures are passed through the anterior rectus fascia and rectus muscle, 4 cm from the medial aspect of the rectus muscle and placed every 2-3 cm (Fig. 9.11). The sutures are placed and tied with gradual loading of tension onto the abdominal wall musculature to achieve closure. Using this simple geometric formula of a 7.5-cm mesh and 4-cm bites, the mesh will be inset flat and tight without wrinkles (Fig. 9.12). s Longer repairs are more effective than short repairs to minimize compliance mismatches at the ends of the repair, especially for patients with incisional hernias found in the midst of rectus diastasis. s The medial aspect of the rectus muscles is closed over the mesh to achieve a direct supported repair. Up to 45 sutures are used for a full abdominal wall closure from xyphoid to symphysis pubis (Fig. 9.13). s For intra-abdominal mesh, an identical technique is performed after mobilization of the falciform ligament and retroperitoneal fat and without a layered closure of the posterior rectus fascia.

12 Chapter 9 Periumbilical Perforator Sparing Component Separation Fig Fig Fig Fig

13 178 Section IV Component Separation 6. Skin Handling s Perforator preservation leaves the skin attached to the abdominal musculature. Approximation of the muscles in the midline recruits skin to the midline and causes it to be redundant. s Routine resection of the midline tissue as a vertical panniculectomy is performed to remove midline wounds, hernia sac, scar, and skin without pulsatile blood flow and decrease potential dead space (Fig. 9.14). s Drains or quilting sutures are important to avoid dead space (Fig. 9.15). 6. Postoperative Care s Patients are given predominantly narcotics for pain control. Nonsteroidal anti-inflammatory drugs blunt the early inflammatory response and, as for orthopedic surgery cases, are avoided. No nasogastric tubes are used. A Foley catheter is left in place until the second day after surgery. s Clear liquids are started on the return of bowel function, typically during the third or fourth postoperative day. s Binders are used to compress the soft tissues back to the abdominal wall. Drains are left in place until drainage is less than 30 ml/day. s Anticoagulation is given during the hospital stay and occasionally in the early postoperative period at home to limit deep vein thrombosis. Patients are discharged 5-6 days after surgery with oral analgesics only prescribed. s Patients are encouraged to walk as tolerated immediately. Nonimpact exercise can begin after 4-6 weeks. Isometric core exercise training can begin at 3 months. Low-impact exercise is permitted at 6 months, and full exercise is allowed at 12 months. s Fig shows the postoperative appearance. Pearls and Pitfalls s Although the total tension on the repair construct and on the rectus muscles may initially seem too tight, clinically the forces at the STI are below the point for suture pull-through and hernia recurrence. s In two different reports in the literature, perforator preservation was shown to decrease local wound complications compared with open component repairs with standard skin undermining. The SSI for open procedures with wide undermining has been consistently reported in the 25% range. Dumanian s report in 2002 was the first to directly compare wound complication rates in component procedures with and without perforator preservation. Perforator preservation decreases local wound complications to 5%-10%. s A narrow mesh placed in the retrorectus position with multiple sutures to distribute forces acts as a pledget to decrease forces at each individual STI, limiting suture pull-through. The large number of sutures essentially quilts the mesh to the abdominal wall following a well-established principle that a well-fixed foreign body does not become infected. s For hernias larger than 12 cm in transverse dimension on computed tomography scan, intra-abdominal mesh is occasionally used. An intact rectus abdominis complex without separation of the posterior sheath as a separate layer allows the use of greater tension on the mesh construct to achieve a direct supported repair.

14 Chapter 9 Periumbilical Perforator Sparing Component Separation 179 Fig Fig A Fig B

15 180 Section IV Component Separation s The mesh is kept narrow to resist wrinkling at its edges, to limit the total amount of foreign material, and to avoid unnecessary elevation of wide tissue flaps. As a side benefit, keeping the sutures nearer to the midline also avoids larger segmental intercostal nerves. The Rives-Stoppa repair with large meshes is associated with a 27% rate of chronic pain; this is possibly avoided with these narrow meshes. s Many surgeons who avoid suture fixation for reasons of utility, difficulty with suture placement, and pain have extrapolated concepts from inguinal hernia repair. Downsides to this strategy of using giant minimally fixed meshes include opening larger soft tissue planes that permit fluid to collect, the development of mesh wrinkles at the periphery when trying to fit a flat mesh to a curved surface, and a poorly stabilized mesh that may slow incorporation. s A narrow mesh designed to stiffen only the midline closure leaves the lateral wall compliant and protective from the phenomenon of pull-through. s This technique of force distribution for a high-tension internal closure owes more to plastic surgery concepts of vascular preservation and orthopedics concepts of suture pull-through and gap formation than to concepts that extend back to William Mayo and pants-over-vest repairs. This technique is generalizable and has been used equally successfully for flank hernia repair. s This technique is straightforward, employing standard surgical maneuvers that are teachable to house staff and can be performed in 2½ hours. Selected References Ghali S, Turza K, Baumann DP, Butler CE: Minimally invasive component separation results in fewer wound-healing complications than open component separation for large ventral hernia repairs, J Am Coll Surg 214: , Gibbons GW, Wheelock FC, Hoar CC, et al.: Predicting success of forefoot amputations in diabetics by noninvasive testing, Arch Surg 114:1034, Iqbal CW, Pham TH, Joseph A, Mai J, Thompson GB, Sarr MG: Long-term outcome of 254 complex incisional hernia repairs using the modified Rives-Stoppa technique, World J Surg 31: , Purnell CA, Park E, Turin SY, et al. Postoperative flank defects, hernias, and bulges: a reliable method of repair, Plast Reconstr Surg 137: , Saulis A, Dumanian GA: Periumbilical rectus abdominis perforator preservation significantly reduces superficial wound complications in separation of parts hernia repairs, Plast Reconstr Surg 109:2275, Souza JM, Dumanian GA: Routine use of bioprosthetic mesh is not necessary: a retrospective review of 100 consecutive cases of intraabdominal midweight polypropylene mesh for ventral hernia repair, Surgery 153: , Taylor GI, Corlett RJ, Dhar SC, Ashton MW: The anatomical (angiosome) and clinical territories of cutaneous perforating arteries: development of the concept and designing safe flaps, Plast Reconstr Surg 127:1447, 2011.