Adhesion formation has been found to be highly prevalent in patients with a history of operations or inflammatory peritoneal processes. These patients are at a high risk of serious intraoperative complications during a subsequent operation if adhesiolysis is performed. These complications include bowel perforation, ureteral or bladder injury, and vascular injury. In order to minimize the risk of these complications, adhesiolysis should only be performed by experienced surgeons, and intraoperative strategies must be adopted. The reduction of the overall incidence of adhesions is essential for subsequent surgical treatments. Anti-adhesion strategies must be adopted for preventing the reoccurrence of adhesions after abdominopelvic operations. The strategies employed to reduce the risk and the overall incidence of adhesions have been elucidated in this article.
Highlights
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Adhesiolysis is associated with serious complications.
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Visualization of potentially endangered anatomical structures during adhesiolysis is necessary.
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Adhesiolysis is a demanding procedure.
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Adhesiolysis should only be performed by experienced surgeons.
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Surgeons should adopt anti-adhesion strategies.
Introduction
In abdominopelvic surgery, the term ‘adhesions’ refers to the connective tissue strands between anatomic structures that are normally not attached to each other. The extent of adhesions can vary from single adhesions with less or no clinical symptoms to adhesions of the whole abdomen and/or pelvis that especially develop after extended previous operations or infections and can be the cause of a variety of intra- and postoperative complications.
Many studies have revealed important insights into the pathogenesis of adhesions, although the diverse influences on adhesion development are still not fully understood. It is well known that the basis of adhesion development is an imbalance between fibrin deposition and fibrinolysis. Fibrin is deposited at a surgical site in a normal response to a surgical trauma. However, factors such as tissue hypoxia or an increased inflammatory reaction contribute to a cytokine environment that hinders the lysis of the deposited fibrin through an interaction between the cytokines and the components of the fibrinolytic system. As a consequence, the fibrin clot is not degraded after a few days (as usual). The following invasion of fibroblasts and other cells causes a reorganization of the clot to a stable strand of connective tissue that may contain vessels and nerves .
Because of the complex influences on adhesion development, it can neither be predicted with a sufficient degree of certainty which patients develop adhesions after an operation nor in which patients adhesions are present before an operation. Data about the incidence of adhesions considerably differ depending on the regarded study which makes a general statement about the improbability of the incidence. However, in most of the studies, the incidence varies between 20% and 93% . These significant variations may be explained by diverse operation and entry techniques as well as by different underlying diseases. The presence of adhesions is more probable in patients with a history of laparotomy or extended operation. However, patients are likely to develop adhesions after laparoscopic surgery, as the latter can reduce the risk of adhesion development but cannot prevent it completely . Furthermore, it is known that some operations such as myomectomy, endometriosis surgery, ovarian and tubal surgery as well as adhesiolysis are high-risk procedures concerning adhesion development and reformation of adhesions irrespective of whether they are performed laparoscopically or by laparotomy (REF34, cave search for original REF!). Even a 20% incidence of adhesion development, and therefore the presence of adhesions in one-fifth of the patients, is alarming and should be the reason for every surgeon to be familiar with strategies to avoid complications during an operation in patients with existing adhesions and also to avoid adhesion in general.
Intraoperative complications through adhesions and approaches to avoid them
In daily routine, every abdominopelvic surgeon is confronted with patients who have adhesions, wherein these can be the cause of the patients’ discomfort, for example, in the case of chronic pelvic pain , infertility , or bowel obstruction , or are found coincidentally while performing an operation for another underlying disease. In both situations, an adhesiolysis must be performed, in the first case to solve the clinical problem and in the second to restore the normal anatomy to make the operation of the underlying disease successful. Adhesiolysis, however, is associated with a high risk of intraoperative complications such as inadvertent bowel, bladder, ureter, and vessel injury. But before performing adhesiolysis, the first critical step, that is, access to the abdominal cavity, carries a significant risk of organ injury due to adhesions. Particularly in the case of laparotomies by a longitudinal incision in the anamnesis, the presence of adhesions in the area of the previous incision in the abdominal wall must be considered ( Fig. 1 ). In a minimally invasive surgery, such as laparoscopy, the presence of umbilical adhesions is of special interest as the insertion of the trocar can lead to organ injury, especially injury of the bowel, due to the adhesions that attach the organs to the abdominal wall ( Fig. 2 ). In a study of 814 patients, umbilical adhesions were found in 0.68% of patients with no previous abdominal surgery (group 1; n = 469), 1.6% with prior laparoscopic surgery (group 2; n = 125), 19.8% with previous laparotomy with a horizontal suprapubic incision (group 3; n = 131) and 51.7% with a previous laparotomy with a midline incision. Although the presence of severe adhesions in the bowel was much less compared with the overall incidence of umbilical adhesions in the single groups, a high number of patients with previous laparotomy were at a potential risk of bowel injury if the umbilical trocar was inserted blindly (group 1: 0.42%, group 2: 0.80%, group 3: 6.87%, and group 4: 31.46%) . Another study investigated the presence of umbilical adhesions in patients with a history of laparoscopy through an umbilical incision. Patients with a history of other surgeries were excluded. Of the 151 patients studied, 32 (21.2%) had umbilical adhesions and 4 (2.6%) bowel adhesions. As a consequence, in patients with a history of laparoscopy or laparotomy, an alternative access to the abdominal cavity such as the Palmer’s point (3 cm below the left costal margin in the mid-clavicular line; Fig. 3 ) should be considered to minimize the risk of inadvertent organ perforation during trocar entry. The occurrence of adhesions at the Palmer’s point after previous operations is unlikely because most abdominopelvic operations are conducted farther from this anatomical region. A first impression of the extent of adhesions in the abdomen can be obtained safely from the Palmer’s point and a decision on how to further operate can be taken. If adhesions are present, a structured approach is recommended. As adhesiolysis is a highly demanding procedure with a high risk of complications, only surgeons with sufficient skill and expertise should perform it. Furthermore, not every possible adhesiolysis should be conducted. Adhesions that do not cause pain, infertility, or future bowel obstructions should only be lysed if they hinder the progress of the operation. However, in many operations, adhesiolysis is inevitable to obtain access to the pelvis as well as to restore normal anatomy to facilitate further operation steps. In such situations, a careful lysis of abdominal wall adhesions should be done firstly for better visibility of the lesser pelvis. The preoperative preparation along the sidewalls of the lesser pelvis enables orientation of extensive adhesions. The adnexa can often be localized in this way and serves as a further orientation point. The first step of preparation near the uterus includes the lysis of adhesions between the uterus and the bowel to mobilize the bowel out of the operation field, thereby minimizing the risk of bowel injury during further preparation steps. The ovaries are localized by further dissecting along the fallopian tubes. In general, adhesions formed between the visceral and the parietal peritoneum can be lysed more easily along the avascular plane, thus ensuring minimal bleeding. The application of traction and countertraction forces sets the tissue under tension and allows easier identification of the avascular plane. Adhesiolysis can be performed by both sharp and blunt dissection techniques in a single operation. Sharp dissection is preferred for dense adhesions as blunt lyses may lead to peritoneal tear and defect. Following sharp adhesiolysis of dense adhesions, the remaining adhesions are lysed by the blunt technique. Aquadissection is an alternative method for blunt adhesiolysis. However, it should be applied carefully as the correct anatomical layers become blurred, making preparation in the correct layer more difficult. Another critical aspect of adhesiolysis is the use of electrocoagulation. Nevertheless, extensive coagulation leads to tissue contraction which, like aquadissection, does not permit precise preparation of the correct layer. Furthermore, the spread of the applied current suggests an increased risk of injury to the surrounding structures. The magnifying effects of the laparoscope enable accurate identification of the adhesion blood vessels and also selective coagulation before lysis. This ensures minimal bleeding during operation which, in turn, reduces the total use of electrocoagulation. However, in the case of adhesions in the omentum majus electrocoagulation is often employed for preoperative preparation, because care must be taken to ensure adequate hemostasis immediately due to increased blood circulation in the omentum majus. In case of inadequate hemostasis, it can be difficult to identify rebleeding in the adipose tissue. In any event, the visualization of the bowel and/or, where necessary, the ureter is of utmost importance.
Intraoperative complications through adhesions and approaches to avoid them
In daily routine, every abdominopelvic surgeon is confronted with patients who have adhesions, wherein these can be the cause of the patients’ discomfort, for example, in the case of chronic pelvic pain , infertility , or bowel obstruction , or are found coincidentally while performing an operation for another underlying disease. In both situations, an adhesiolysis must be performed, in the first case to solve the clinical problem and in the second to restore the normal anatomy to make the operation of the underlying disease successful. Adhesiolysis, however, is associated with a high risk of intraoperative complications such as inadvertent bowel, bladder, ureter, and vessel injury. But before performing adhesiolysis, the first critical step, that is, access to the abdominal cavity, carries a significant risk of organ injury due to adhesions. Particularly in the case of laparotomies by a longitudinal incision in the anamnesis, the presence of adhesions in the area of the previous incision in the abdominal wall must be considered ( Fig. 1 ). In a minimally invasive surgery, such as laparoscopy, the presence of umbilical adhesions is of special interest as the insertion of the trocar can lead to organ injury, especially injury of the bowel, due to the adhesions that attach the organs to the abdominal wall ( Fig. 2 ). In a study of 814 patients, umbilical adhesions were found in 0.68% of patients with no previous abdominal surgery (group 1; n = 469), 1.6% with prior laparoscopic surgery (group 2; n = 125), 19.8% with previous laparotomy with a horizontal suprapubic incision (group 3; n = 131) and 51.7% with a previous laparotomy with a midline incision. Although the presence of severe adhesions in the bowel was much less compared with the overall incidence of umbilical adhesions in the single groups, a high number of patients with previous laparotomy were at a potential risk of bowel injury if the umbilical trocar was inserted blindly (group 1: 0.42%, group 2: 0.80%, group 3: 6.87%, and group 4: 31.46%) . Another study investigated the presence of umbilical adhesions in patients with a history of laparoscopy through an umbilical incision. Patients with a history of other surgeries were excluded. Of the 151 patients studied, 32 (21.2%) had umbilical adhesions and 4 (2.6%) bowel adhesions. As a consequence, in patients with a history of laparoscopy or laparotomy, an alternative access to the abdominal cavity such as the Palmer’s point (3 cm below the left costal margin in the mid-clavicular line; Fig. 3 ) should be considered to minimize the risk of inadvertent organ perforation during trocar entry. The occurrence of adhesions at the Palmer’s point after previous operations is unlikely because most abdominopelvic operations are conducted farther from this anatomical region. A first impression of the extent of adhesions in the abdomen can be obtained safely from the Palmer’s point and a decision on how to further operate can be taken. If adhesions are present, a structured approach is recommended. As adhesiolysis is a highly demanding procedure with a high risk of complications, only surgeons with sufficient skill and expertise should perform it. Furthermore, not every possible adhesiolysis should be conducted. Adhesions that do not cause pain, infertility, or future bowel obstructions should only be lysed if they hinder the progress of the operation. However, in many operations, adhesiolysis is inevitable to obtain access to the pelvis as well as to restore normal anatomy to facilitate further operation steps. In such situations, a careful lysis of abdominal wall adhesions should be done firstly for better visibility of the lesser pelvis. The preoperative preparation along the sidewalls of the lesser pelvis enables orientation of extensive adhesions. The adnexa can often be localized in this way and serves as a further orientation point. The first step of preparation near the uterus includes the lysis of adhesions between the uterus and the bowel to mobilize the bowel out of the operation field, thereby minimizing the risk of bowel injury during further preparation steps. The ovaries are localized by further dissecting along the fallopian tubes. In general, adhesions formed between the visceral and the parietal peritoneum can be lysed more easily along the avascular plane, thus ensuring minimal bleeding. The application of traction and countertraction forces sets the tissue under tension and allows easier identification of the avascular plane. Adhesiolysis can be performed by both sharp and blunt dissection techniques in a single operation. Sharp dissection is preferred for dense adhesions as blunt lyses may lead to peritoneal tear and defect. Following sharp adhesiolysis of dense adhesions, the remaining adhesions are lysed by the blunt technique. Aquadissection is an alternative method for blunt adhesiolysis. However, it should be applied carefully as the correct anatomical layers become blurred, making preparation in the correct layer more difficult. Another critical aspect of adhesiolysis is the use of electrocoagulation. Nevertheless, extensive coagulation leads to tissue contraction which, like aquadissection, does not permit precise preparation of the correct layer. Furthermore, the spread of the applied current suggests an increased risk of injury to the surrounding structures. The magnifying effects of the laparoscope enable accurate identification of the adhesion blood vessels and also selective coagulation before lysis. This ensures minimal bleeding during operation which, in turn, reduces the total use of electrocoagulation. However, in the case of adhesions in the omentum majus electrocoagulation is often employed for preoperative preparation, because care must be taken to ensure adequate hemostasis immediately due to increased blood circulation in the omentum majus. In case of inadequate hemostasis, it can be difficult to identify rebleeding in the adipose tissue. In any event, the visualization of the bowel and/or, where necessary, the ureter is of utmost importance.
Adhesiolysis and the associated risk in detail
Bowel perforation
During adhesiolysis, the risk of bowel injury (enterotomy) is particularly high due to the presence of adhesion-associated bowel obstructions. Furthermore, the bowel can be located outside its natural anatomical position due to the adhesions and thus may unexpectedly appear in the operation field. The presence of dense adhesions between the bowel and the abdominal wall does not facilitate lysis, thereby increasing the risk of injury during adhesiolysis. In addition to the direct injury of the intestine during sharp adhesiolysis, coagulation of blood or anatomical structures prior to sharp dissection can cause thermal damage to the intestine ( Figs. 4a, b, and 5 ). The incidence of bowel injury during adhesiolysis varies from 3% to 24% . A meta-analysis conducted to estimate the disease burden of the most important complications of postoperative abdominal adhesions identified 16 studies (2565 procedures) in which the need for adhesiolysis was confirmed. The overall incidence of enterotomy was 5.8% (95% confidence interval: 3.7–7.9%). It seemed to depend on the type of surgery and was found to be highest in lower gastrointestinal tract surgery (8.7%, 3.8–3.6%), followed by gynecological surgery (4.8%, 0.6–9.1%). It was significantly lower in 30 laparoscopic cohorts (1.8%, 1.2–2.4%) than in eight open cohorts (8.9%, 4.2–13.6%). A similar pattern was observed in two studies that compared laparoscopic and open surgery (odds ratio: 0.21, 0.05–0.90) . Another study identified four predictors of adhesiolysis-related bowel injury, namely the number of previous laparotomies, anatomical site of the operation (highest risk in the lower gastrointestinal tract followed by the abdominal wall), the presence of bowel fistula and laparotomy via a preexisting median scar . It is essential to develop a strategy to minimize the risk and incidence of inadvertent bowel injury. The bowel should be held at a sufficient distance from the surgical field for the prevention of injury. This is done using an atraumatic bowel grasper. In case of extensive adhesions, the correct preparation layer between the visceral and parietal peritoneum can be identified through careful traction and countertraction. The taut adhesions are then snipped on the side facing away from the bowel. Vascular adhesions should be coagulated before dissection. A bowel injury through an incision is at best detected immediately through visualization of the exposed muscle layer or release of intestinal fluid, so that suturing of the defect can be performed. Thermal damage to the bowel is often detected only after a few days, because the opening of the damaged intestinal part occurs after a latency period of hours to a few days. If adhesions are expected to develop preoperatively and an adhesiolysis is planned, it is advisable to prepare the bowel through laxative measures, since this reduces the germ load which, in turn, minimizes the risk of infection in case of an injury. During the postoperative period, care must be taken on the appearance of signs of peritonitis and the course of inflammatory parameters in order to detect any perforation with subsequent peritonitis as early as possible. In this case, an immediate reoperation is necessary. Peritonitis poses a serious threat to the patients, and hence the risk of its occurrence must be reduced. Therefore, lysis of intestinal adhesions should always be performed with care and only by an experienced surgeon.
