Averting adhesions: Surgical techniques and tools
A laparoscopic approach, microsurgical principles, and barriers or instillates can reduce adhesions
IN THIS ARTICLE
CASE Could bowel obstruction have been prevented?
B.H., 34, undergoes laparotomy for removal of an 8-cm myoma and a left ovarian cyst, which is found to be an endometrioma. Now she has come to the emergency department complaining of abdominal distension, pain, vomiting, and an inability to defecate. Small-bowel obstruction is diagnosed. Another laparotomy reveals that the obstructed bowel is adhered to the prior surgical incision.
Could this scenario have been avoided?
Adhesions need no introduction. Every surgeon is familiar with them; they are so ubiquitous they sometimes seem to be a given. Nevertheless, there are steps you can take to reduce the incidence of postoperative adhesions. In this article we describe surgical techniques, barriers, and peritoneal instillates that can help.
Intra-abdominal adhesions can cause pain, infertility, and bowel obstruction, and complicate future surgeries.1-3 Most studies suggest that more than 50% of women with adhesion-related small bowel obstruction have a history of gynecologic or obstetric operations. Within 1 year of laparotomy, adhesions cause intestinal obstruction in 1% of patients. After even a single previous abdominal operation, 93% of patients develop adhesions, compared with only 10.4% of patients who have never undergone laparotomy (FIGURE 1).1-3
We recently found an incidence of adhesion-related intestinal obstruction after operation for a benign gynecologic indication of 8 cases per 1,000 operations.4 Total abdominal hysterectomy (TAH) was the most common cause of small bowel obstruction (13.6 cases per 1,000 surgeries).
FIGURE 1 Adhesions through the laparoscope
Severe adhesions between the intestines and omentum to the uterus.
Omental adhesions to the anterior abdominal wall.
Adhesion between the intestine (lower left hand corner) and the anterior abdominal wall.
Tissue desiccation, necrosis, and the use of reactive suture material can predispose the patient to adhesion formation. Many studies in animal models have demonstrated an association between adhesions and these parameters. The following practices can help:
- Continuously irrigate the operative field during laparotomy
- Use nonreactive suture material such as polyglycolic acid (Dexon), polyglactin (Vicryl), or polydioxanone (PDS). Using reactive material, such as catgut, is discouraged
- Use powder-free gloves and prevent foreign-body infiltration (eg, powder, gauze, lint) of the wound.
No single parameter is as important as good surgical technique, attention to microsurgical principles, and precise hemostasis (TABLE 1).
Surgical principles to reduce adhesion formation
Take a laparoscopic approach when feasible
Minimize tissue necrosis
Provide meticulous hemostasis
Liberally irrigate the abdominal cavity
Use nonreactive suture materials
When performing laparotomy
Peritoneal closure is unnecessary
Several randomized trials have demonstrated that closure of the parietal or visceral peritoneum is unnecessary. This practice is associated with slightly longer operating times and greater postoperative pain and may cause more adhesions.5 In 1 study, the rate of adhesion formation after laparotomy with peritoneal closure was 22.2%, compared with 16% without closure.6
Ellis7 noted an increasing number of medicolegal claims arising from adhesion-related complications, and recommended that “peritoneal defects and the pelvic floor should be left open, since they rapidly reperitonealized.”
Laparoscopy is more protective than open surgery
Abdominal surgeries injure tissues more severely than laparoscopy, and are associated with a greater degree of adhesion formation in up to 94% of patients, although laparoscopy can also cause adhesions.2 Laparoscopy is more protective because it involves minimal handling of tissue and little manipulation of the internal organs. Surgery is performed in a closed environment, tissue moistness is maintained, and contamination with glove powders or lint does not occur. In addition, the tamponade effect of carbon dioxide pneumoperitoneum facilitates hemostasis. Laparoscopy is also associated with a lower incidence of infection.
Many adhesion-reducing products have been evaluated in human and animal models. A basic assumption behind these substances is that surgically injured tissues heal without forming adhesions if the traumatized surfaces in apposition are separated to allow each to heal independently.
The ideal substance is resorbable, adherent to the traumatized surface, applicable through the laparoscope, and inexpensive, with high biocompatibility. So far, no substance or material has proved to be unequivocally effective.
Adhesion barriers are widely studied
The following products are among the most widely investigated substances (TABLE 2).
Expanded polytetrafluoroethylene, or ePTFE. Gore-Tex surgical membrane, constructed of ePTFE (Preclude, WL Gore), is nonabsorbable and produced in thin sheets (0.1 mm), with an average pore size of less than 1 μm. It is sutured to the tissue so that it overlaps the incision by at least 1 cm. It prevents adhesion formation—and reformation—independent of the type of injury. It is also effective in the presence of blood.
In a randomized trial, ePTFE decreased postmyomectomy and pelvic sidewall adhesions.8,9 In our experience, this is the most effective adhesion-reducing substance available. It is not widely used, however, because it is nonabsorbable and has to be fixed to the tissue.
Combined hyaluronic acid (HA) and carboxymethylcellulose (CMC). Known most widely by its trade name, Seprafilm (Genzyme Corp), this bioresorbable product is composed of sodium HA and CMC, a combination that produces a transparent and absorbable membrane that lasts for 7 days after application.10,11
In a study of 259 patients undergoing laparotomy for bowel resection or enterolysis, the incidence of repeat bowel obstruction was similar in the group treated with Seprafilm and the historical control group.11 However, 9 of 12 bowel obstructions in the treated group resolved without surgery, compared with 5 of 12 in the control group. The enterolysis rate in the treated group was 1.5%, compared with 3.9% in the control group.
Because of its stickiness, Seprafilm is not ideal for laparoscopy. However, it can be rolled and passed through the trocar, with the film separated from its paper backing inside the abdominal cavity.
Oxidized regenerated cellulose. Known under the brand name Interceed (TC7), this absorbable adhesion barrier (Johnson & Johnson) is the most widely studied product available today. Several randomized trials have shown that it reduces postoperative formation of adhesions on the pelvic sidewalls and near the adnexa.12-14
The efficacy of Interceed is reduced in the presence of blood. It is the easiest adhesion barrier to use at laparoscopy.
Newer agents in development include CMC and polyethylene oxide (PEO) composite gel (Oxiplex/AP, FrizoMed) and polylactide (PLa): copolymer of 70:30 Poly (L-lactide-co-D,L-lactide) film (SurgiWrap, Mast Biosurgery).
The array of selected adhesion barriers and peritoneal instillates, and how they work
Expanded polytetrafluoroethylene (Preclude [Gore-Tex surgical membrane])
Hyaluronic acid and carboxymethylcellulose (Seprafilm)
Oxidized regenerated cellulose (Interceed [TC7])
4% icodextrin (Adept)
Hyaluronic acid and ferric ion (InterGel)
HAL-C bioresorbable membrane (Sepracoat)
Hydrogel (SprayGel) to form membrane
Fibrin sealant (Tissucol)
The newest peritoneal instillate is 4% icodextrin solution (Adept, Baxter BioSurgery). It is FDA-approved for the reduction of adhesion reformation after laparoscopic adhesiolysis. In a randomized study, the authors found that instillation of 4% icodextrin solution decreased adhesion formation and reformation after laparoscopic gynecologic surgery.15
Hyaluronic acid. Intergel (Lifecore, Johnson & Johnson Gynecare) is a cross-linked HA with ferric ion. It effectively reduces the number, severity, and extent of adhesions after abdominal operation.16 However, the product was withdrawn from the market after several reports of late-onset postoperative pain requiring surgery.
Sepracoat. This product (HAL-C Bioresorbable Membrane, Genzyme Corp) is a modification of Seprafilm. It coats serosal surfaces and is absorbed from the peritoneal cavity within 7 days. Its mechanism of action includes the reduction of tissue desiccation. Preliminary data show it to be effective in reducing postoperative adhesions.17 However, it did not receive FDA approval for clinical use, and was withdrawn from the market in 1997.
Hydrogel. A novel technique of substance delivery into the abdominal cavity is by combining 2 streams of liquid polymers, delivered via catheter to target tissue. When combined, the 2 streams produce a solid polymer within minutes. Sprayable hydrogel (SprayGel, Confluent Surgical) can be easily applied at laparoscopy. The solid polymer acts as an adhesion barrier and can potentially serve as a vehicle for localized delivery of drugs.
In a randomized study, Mettler et al18 evaluated 66 women who underwent myomectomy with or without SprayGel application. Second-look laparoscopy was performed in 40 women. Seven of 22 patients (31.8%) in the SprayGel group and 2 of 18 patients (11.1%) in the control group remained free of adhesions. However, the power of this study is small, and the authors did not break the women into subgroups based on whether they underwent surgery via laparoscopy or laparotomy. In the United States, the pivotal study of SprayGel was stopped prior to completion.
A similar product is a sprayable selfpolymerizing gel called Adhibit (Angiotech). An unpublished study from Europe showed it to be promising.
Fibrin sealant. Fibrin glue (Tissucol, Baxter) has been used as an adhesion-reducing substance, although clinical data on this application are scarce. This product is not approved by the FDA.
Myomectomy performed through a laparotomy incision usually causes adhesions, so women who undergo this operation are good candidates for adhesion-reducing substances. The rate of adhesion formation after abdominal myomectomy is more than 90%—and it is 70% by laparoscopy.
Two helpful preventive strategies:
- Use a laparoscopic approach when feasible, and
- apply a barrier, such as the Gore-Tex ePTFE membrane, Seprafilm, or, if the myomectomy incision is not oozing, Interceed. Instillation of 1 L of 4% icodextrin may also be useful.
Most small-bowel obstruction follows abdominal hysterectomy, although a considerable period of time may pass before the problem occurs. When it does, a general surgeon usually manages the patient, and the treating gynecologist is unaware of this serious complication.
We recently found an incidence of adhesion-related small-bowel obstruction of 14 cases per 1,000 total abdominal hysterectomies and 1 case per 1,000 vaginal hysterectomies (P<.001).4 We did not encounter any small-bowel obstruction among 303 cases of laparoscopic supracervical hysterectomy.
Application of an adhesion-reducing substance to the vaginal vault or cervical stump may prevent small-bowel obstruction. Most adhesions implicated in small-bowel obstruction involve the vaginal vault. Appropriate products include Interceed, Preclude, Seprafilm, or perhaps Adept.
No adhesion-reducing substance has proved to be effective in increasing the pregnancy rate after a fertility-promoting procedure such as reconstructive tubal surgery or surgery for endometriosis.
B.H., the patient described at the beginning of this article, should have had her initial surgery performed by an experienced laparoscopist, with minimal coagulation, meticulous hemostasis, “layered” repair of the myomectomy incision using nonreactive sutures, and liberal irrigation of the abdominal cavity. At the conclusion of the operation, the incision could have been covered with Gore-Tex surgical membrane or Seprafilm (or Interceed if there was no oozing) at least 1 cm beyond the incision. Instillation of Adept might have been useful as well.