At present, there is no unanimously recognized effective method to prevent intestinal adhesions and intestinal obstruction. Clinical experience has confirmed that several methods are available, one is to reduce the scope and degree of intestinal adhesions, and the other is to recognize that adhesions will inevitably occur, but they can be formed in an orderly manner, not sharp-edged adhesions, so as to avoid the occurrence of intestinal adhesions.
1, the type of intestinal adhesions
1.1 Early adhesions
Inflammatory intestinal adhesions begin after surgery, and are usually formed completely after 2 weeks after surgery. The adhesions formed in about 2 to 6 weeks are mainly inflammatory adhesions. The appearance of these adhesions is characterized by inflammatory edema, and the intestinal tube is closely adhered to the intestinal tube, and the boundary seems to be absent. The word “sticky” best reflects its characteristics. It cannot be separated by knife or scissors (i.e., sharp separation). On the contrary, in the early stage, i.e. within 2 weeks after surgery, the adhesions can be separated by tearing and pulling of the fingers (i.e. blunt separation).
For adhesions involving the whole abdominal cavity, it takes about 3 months to evolve completely into membranous adhesions, i.e., the so-called release of adhesions. The release of adhesions is not the disappearance of adhesions, but only the transformation into another form of adhesions (i.e., membranous adhesions).
1.2 Mature adhesions
Mature adhesions include membranous adhesions, scar adhesions, and mixed adhesions with both characteristics. Membranous adhesions are the final evolutionary form of adhesions. At this point, the adhesions between the intestinal tubes become a thin fibrous membrane visible to the naked eye, which is very tough. However, the gaps between the intestinal tubes can be pulled out and can be easily separated by surgical scissors. The thin fibrous membrane can even be separated bluntly by scissors or fingers. However, if the membranous adhesions are not fully mature, blunt separation may cause tearing of the plasma muscle layer of the intestinal wall. The word “adhesions” can describe the characteristics of membranous adhesions, in which the intestinal tubes are only “connected” together, but no longer “sticky”.
The inflammatory adhesions are too heavy or there are tiny foreign bodies in the abdominal cavity, which will stimulate the local fibrous tissue proliferation, forming a scar such as skin trauma, so it is called scar adhesions. The lamellar scarring adhesions are like skin “scars”, which are tough and have no boundaries. It requires new and sharp scissors to separate them. In the heaviest cases, a new sharp scalpel is needed to separate them. Punctate scar-like adhesions, like rivets, are mixed with membranous adhesions, and if they are forcibly and bluntly separated, the intestinal plasma layer will be severely torn and the mucosal layer will be exposed. Sclerosing peritonitis after chemotherapy is its most serious manifestation. “Corded adhesions” are special strip-shaped scar adhesions. Mixed adhesions are scarred adhesions mixed with membranous adhesions, often after severe contamination or infection of the abdominal cavity, or the addition of so-called anti-adhesive substances. After several years of sclerosing peritonitis, it can slowly evolve into mixed adhesions.
2, common types of adhesive intestinal obstruction
1.1 post-operative adhesive intestinal obstruction
Once the abdominal cavity is opened, abdominal adhesions will inevitably occur. Theoretically, any caesarean operation will lead to intestinal adhesions. However, adhesional intestinal obstruction does not necessarily occur in all caesarean operations. Some types of surgery have a higher chance of developing adhesive bowel obstruction postoperatively. For example, after splenectomy, after perforation of the gastrointestinal tract, after partial or total gastrectomy, after direct incisional cholecystectomy, and after appendiceal abscess or gangrenous appendectomy. Only one disease is less likely to form extensive adhesions after surgery, namely Crohn’s disease. In these patients, there are only a few adhesions around the fistula or around the anastomosis.
The occurrence of adhesive bowel obstruction is highly correlated with the degree of contamination of the abdominal cavity and alteration of the normal anatomic position within the abdominal cavity. After bacterial contamination of the abdominal cavity (infection) or stimulation by inflammatory substances, inflammation of the intestinal wall followed by fibrous tissue proliferation occurs, resulting in the formation of adhesions. Therefore, the more severe the degree of peritonitis, the heavier and more extensive the adhesions. This is the case with adhesions in patients with severe pancreatitis. The more mechanical stimulation, the more inflammation of the intestinal wall and the more intestinal adhesions. Foreign body stimulation can also aggravate adhesions, such as silk sutures under the incision is often the heaviest adhesions.
After partial or complete resection of some organs, leaving obvious cavities in the abdominal cavity, such as splenectomy, the small intestine is displaced to the splenic fossa, changing the normal course of the small intestine, coupled with the factor of adhesions, the intestinal tube is easy to form an acute angle at the turn, forming an obstruction. If malnutrition, excess water and infection occur after surgery, intestinal obstruction can occur immediately. After the inflammatory edema of the intestinal wall subsides, the obstruction can be relieved, but it is very easy to recur. The intestinal obstruction that occurs after combined abdominal perineal proctocolectomy, anterior rectal resection and adnexal hysterectomy, when the small intestine falls into the pelvic cavity and adheres to the pelvic wall and forms an acute angle with local hanging, is also this type of intestinal obstruction.
The occurrence of adhesive intestinal obstruction is mostly caused by improper food intake and is also related to seasonal changes [ 4 ]. Intestinal obstruction occurs when the intestinal canal turns from obtuse to acute at the turn of the canal due to excessive intestinal contents or oversized food mass, and the intestinal contents cannot pass through. The above-mentioned adhesive intestinal obstruction are all intestinal obstruction occurring after 3 months of caesarean operation, mostly caused by mature adhesions. In fact, early postoperative inflammatory adhesions can also form intestinal obstruction. “Early postoperative inflammatory intestinal obstruction” is a typical form of intestinal obstruction caused by inflammatory adhesions [ 2 ]. In the early stage of laparotomy, the intestine exposed outside the incision can also be obstructed by inflammatory adhesions and edema of the intestinal wall, resulting in the inability to implement enteral nutrition.
2.2 Intestinal adhesions and intestinal obstruction caused by intraperitoneal chemotherapy
After abdominal chemotherapy, radiotherapy drugs can cause a severe inflammatory reaction in the abdominal wall and pelvic wall, resulting in more serious abdominal adhesions. These adhesions occur in a wide range of areas and can be formed wherever chemotherapy drugs are administered. The adhesions are predominantly scarred, and the abdomen is hard as a rock on palpation. The intestinal canal is densely confined by the scar, and the intestine has obvious motor dysfunction after peritonitis, so it is also called sclerosing peritonitis. According to our long-term follow-up, these patients can tolerate enteral nutrition after a few months, but they cannot receive the “meal” of nutrients, i.e., they cannot eat. It takes several years for the scar to soften and the abdomen to become soft.
2.3 Intestinal adhesions caused by radioactive intestinal injury
Radioactive intestinal injury can cause damage to the whole layer of the intestine. The damage to the intestinal mucosa is radioactive mucositis. Injury to the intestinal plasma layer causes inflammatory reaction and scarring of the intestinal wall. Because the manifestations of radiation injury can take up to several years to manifest, the abdominal adhesions manifest as a mixture of inflammatory, membranous and scarring adhesions.
The most typical is radiation injury caused by radiotherapy to the pelvis and lower abdomen. The ileum and pelvic cavity form adhesions that can cause intestinal obstruction after eating with a little carelessness. If combined with muscle layer damage, the intestinal canal is more likely to be scarred and
obstruction will occur. In this case, there are factors of adhesions and intestinal lumen narrowing. The radiological intestinal injury after rectal cancer or hysterectomy is more serious, and adhesional intestinal obstruction is more likely to occur. Because of the adhesions that occur after surgery, the ileum is fixed in a specific position in the pelvic wall, and the intestine can no longer move, and intestinal obstruction occurs soon after radiation exposure to the fixed intestinal segment (mostly at the end of ileum 15 cm).
3.Reducing the scope and degree of intestinal adhesions and preventing intestinal obstruction
3.1 Abdominal flushing
Repeated flushing of the abdominal cavity with saline is the only effective method so far to reduce the extent and degree of abdominal adhesions. The amount of flushing can be as little as 60 mL/kg or as much as 300 mL/kg, and through flushing, the residual foreign bodies, broken necrotic tissues, bacteria and bacterial products, pus and fibrous plaques (lumps) in the abdominal cavity are obviously reduced, and the fibrous tissue proliferation formed by these substances stimulating the peritoneum is reduced.
Through observation of patients undergoing secondary surgery, we found that abdominal irrigation was effective in reducing the degree and extent of abdominal adhesions. In patients with a large amount of flushing from the previous surgery, the intestinal canal was found to be only a “thin” and silky layer of fibrous membranes after re-entering the abdomen by dissection.
3.2 Drug prevention
Through a large number of observations on patients after multiple operations, we found that, so far, we have not found a drug that can effectively reduce abdominal adhesions. Some domestic literature claims that there are drugs that can reduce abdominal adhesions, and they have been confirmed in animal studies. However, there is a lack of multicenter bulk prospective, randomized, double-blind clinical trial studies, which are mostly single-center empirical presentations. In practice, there are real difficulties in conducting clinical trials. Firstly, there is a lack of quantitative description of abdominal adhesions, secondly, most patients do not have the opportunity to undergo reoperation to observe abdominal adhesions, thirdly, long-term follow-up is needed, and fourthly, the occurrence of intestinal obstruction with intestinal adhesions is multifactorial, such as the way of eating can lead to the occurrence of intestinal obstruction, not to mention the type of food eaten.
In patients with intestinal fistulas after intestinal adhesions and intestinal obstruction surgery, we found that some anti-adhesion drugs were added in the previous surgery, but some patients had more serious adhesions than in similar surgeries, with scarred adhesions all over the abdominal cavity and abnormal difficulties in separating the adhesions.
4, intestinal alignment surgery to prevent the occurrence of intestinal obstruction
4.1 Indications for intestinal alignment
Intestinal alignment is a last resort treatment when adhesional intestinal obstruction occurs repeatedly and no effective treatment is available. It is not the first choice and should not be widely used. Patients with intestinal obstruction caused by simple cord adhesions do not need to undergo complex intestinal alignment after cutting the cords and releasing the obstructed intestine. Only in patients with recurrent intestinal adhesions and intestinal obstruction after more than two operations, it is advisable to perform it; in a few patients, after extensive intestinal separation, the intestinal wall is rough and the intestinal plasma layer is heavily damaged, and it is predicted that adhesive intestinal obstruction will inevitably occur, intestinal alignment can be performed after surgery. Foreign literature reports that only 10% of patients with adhesive intestinal obstruction require intestinal alignment. This is consistent with our surgical experience.
4.2 Parenteral alignment
It is important to emphasize the suture material used for extra-intestinal alignment: absorbable sutures are used to close the mesentery. The purpose of this is that after the small intestine has completed “normal adhesion” according to the intraoperative requirements, the sutures are absorbed and do not cause permanent intestinal mechanical obstruction due to improper suturing. However, in clinical practice, we have found that some doctors use silk sutures that are difficult to absorb, with the result that once they are not properly aligned, postoperative complications cannot be eliminated by waiting and non-surgical treatment.
The sutures are placed between the intestinal wall and the intestinal wall, and if the intestinal function is restored and the sutures remain fixed between the two intestinal canals, they may cause rupture of the intestinal plasma layer and the entire intestinal wall, eventually leading to the development of an intestinal fistula. Because of the many problems, external alignment is rarely used in domestic and foreign surgical clinics today. The authoritative literature on the subject is rare.
4.3 Intestinal alignment
Intestinal alignment is still in use. The method of intestinal alignment is divided into cathartic and retrograde. The cathartic method is less likely to form a stoma during extraction, but has the potential to cause intussusception. The retrograde method can avoid intussusception during extraction, but there is a possibility of forming an appendiceal fistula during extraction.
Compared with the conventional method, the tube can be removed 11-14 days after intestinal alignment. Otherwise, the patient may suffer from abdominal pain due to the resumption of intestinal motility. At this time, adhesions have already formed, and it is not very meaningful to place them for too long.
The main shortcoming of intestinal alignment is that it increases the area of surgical operation and prolongs the operation time. To complete the intestinal alignment, it is necessary to repeatedly squeeze the intestinal canal several times, which increases the intestinal canal congestion and edema. The alternative is to perform a partial alignment, i.e., to align only the part of the intestine with a rough wall. Clinicians need to weigh the pros and cons and decide on the trade-offs based on surgical experience, the extent and degree of separation and the patient’s general condition.
5, prevention of postoperative intestinal adhesions intestinal obstruction of some empirical means
5.1 General principles
To reduce unnecessary separation, for intestinal obstruction caused by intestinal fistula, adhesive cords and local adhesions, it is clear that the intestinal canal is open at the distal and proximal ends of the lesion before surgery, and after removing the fistula and reconstructing the digestive tract and releasing the cords and local adhesions, it is not necessary to
After the fistula is excised and the digestive tract is reconstructed and the cords and local adhesions are released, extensive separation is not necessary. Otherwise, it will cause more extensive intestinal adhesions and lay the groundwork for the occurrence of the next adhesive intestinal obstruction.
The debridement of necrotic tissues should be stopped. Otherwise, the trauma left by the debridement will be the basis for the formation of adhesions. The blood exuded from the wound surface after debridement is also the material causing the formation of adhesions. However, the necrotic and broken tissues that are free in the abdominal cavity should be eliminated as much as possible. The best way to remove it is to use saline for peritoneal irrigation.
As much as possible, ligation and suturing should be done with absorbable sutures, and reconstruction of the digestive tract should be done with anastomoses and sutures. Avoid the formation of granulomas and adhesions with silk threads, which can occur with the use of large amounts of silk threads. During the operation, treat the tissue gently and avoid repeated rubbing and squeezing. Avoid blocking the blood supply to the intestinal canal for a long time, reduce the time of intestinal ischemia, and reduce the inflammatory edema of the intestinal wall.
5.2 Avoid unnecessary jejunostomy and ileostomy
The standard jejunostomy requires purse-string embedding, tunnel embedding and abdominal wall draping. If the abdominal wall is not suspended properly, it can lead to jejunostomy suspension.
If it is not properly suspended from the abdominal wall, the jejunostomy can be suspended at an acute angle to form a mechanical obstruction. Strictly speaking, this is also a kind of adhesional intestinal obstruction, that is, the adhesion between the abdominal wall and the jejunostomy caused by manual suturing, which can cause obstruction if it is not done properly. The jejunostomy is usually chosen at about 15 cm below the jejunal flexor ligament, which can avoid the hanging of the jejunostomy into an angle.
5.3 Avoid shortcut surgery as much as possible
Short-cut surgery, i.e. short-circuit surgery, is one of the traditional methods for the treatment of adhesive intestinal obstruction. It is an expedient solution when the intestinal adhesions and intestinal obstruction parts cannot be separated. Through long-term clinical observation, it is found that intestinal obstruction will still recur after surgery. Due to the formation of a small local circulation, when the obstruction site is reopened later, the abdominal distension will be increased, and intestinal obstruction will be more likely to occur. It was found that the short-circuited intestine was atrophied and the intestinal wall was thin due to the lack of effective intraluminal nutrition, and the original open intestine was easily broken during surgical separation, and it was not easy to repair after the breakage. In the absence of normal intestinal fluid, the intestinal cavity of the open intestinal canal is devoid of factors that inhibit bacterial proliferation, and the bacteria in the intestinal cavity will overproliferate, which, together with the atrophy of the intestinal mucosa, will easily translocate intestinal bacteria or toxins and cause chills and fever. Therefore, it is better to perform a short-circuit operation than not to perform any operation for the adhesional intestinal obstruction that cannot be separated, especially for the intestinal obstruction with inflammatory factors. In fact, adhesional intestinal obstruction can be mostly relieved. Of course, as a palliative treatment, short-circuit surgery across the cancerous obstruction can still be performed.
5.4 Intraperitoneal avoidance of adhesion-inducing artificial patches
In recent years, with the use of various artificial patches, intestinal adhesions and intestinal obstruction due to improper use of patches have occurred, and in serious cases, they may lead to the occurrence of intestinal fistula. For abdominal defects, patch repair methods include onlay, inlay, and underlay. The most prone to adhesions is the inlay type, which is prone to intestinal adhesions because the patch is in direct contact with the abdominal cavity.
Patches that can clearly cause intestinal adhesions include polypropylene mesh and polyester fabric. These materials can abrade the intestinal wall and stimulate granulation, which can facilitate temporary abdominal closure and skin grafting of the wound in patients with open abdominal cavity, but not permanent reconstruction of the abdominal wall. Continuous abrasion and granulation will cause extensive intestinal adhesions under the mesh and around the mesh. Granulation can also grow within the mesh of the patch, making it extremely difficult to remove the mesh. Deformation of the mesh can cause intestinal obstruction. Prolonged abrasion can also cause intestinal rupture leading to the development of intestinal fistulas.
A proven patch that can reduce abdominal adhesions is PTFE. However, its tensile strength is poor, so there are products that paste polypropylene mesh and PTFE together to give full play to the tensile capacity of polypropylene and the anti-adhesive capacity of PTFE, but the PTFE surface must be placed on the visceral surface of the abdominal cavity, otherwise, the effect is counterproductive.
The ideal method of abdominal wall repair is to use a covered repair with a layer of peritoneal tissue or hernia sac tissue on the inside and polypropylene mesh on the outside. It would be better to add a layer of rectus abdominis tissue in front of the peritoneal tissue through the technique of sheath separation of rectus abdominis and then reinforced with polypropylene mesh.
6.Non-surgical methods to prevent intestinal adhesions and intestinal obstruction
Lifestyle change is an important means to prevent the frequent occurrence of adhesive intestinal obstruction. This is a problem often ignored by both clinicians and patients. Surgery is not the only way to solve the disease. If patients do not change their lifestyle and “eat and drink a lot”, they will still have intestinal obstruction even after intestinal alignment surgery.
The correct way of eating should be to consume small amounts of food several times, that is, the so-called “less food and more meals”. Avoid the instantaneous increase of intestinal contents, which may cause the adherent intestine to drop down into an angle. Patients with frequent adhesive intestinal obstruction should not eat food with crumbled food. First, try to eat less insoluble dietary fiber, such as leeks, bamboo shoots or bamboo shoots, the so-called crude fiber; second, eat less food containing tannic acid, such as persimmon, hawthorn and dates. Tannic acid in these foods will make the protein deformation and the formation of the group fast, into the intestinal cavity is not easy for the digestive juices and the mechanical movement of the small intestine crushed, in the intestinal tube adhesion hanging into the corner of the formation of obstruction.
7.Conclusion
There is no one-and-done solution for adhesive intestinal obstruction. In addition to the above methods to reduce the occurrence of adhesions, the best way is to summarize the law of occurrence of adhesional intestinal obstruction each time. It is more important to avoid eating the type of food that caused the obstruction than to operate again. Intestinal alignment should be considered only in cases of frequent adhesive bowel obstruction despite repeated attention to lifestyle [5]. Lifestyle changes should still be observed after intestinal alignment. After the occurrence of adhesive intestinal obstruction, if there is a long asymptomatic “quiet period”, the intestinal wall will be less inflammatory edema, the adhesions will gradually evolve from scar adhesions to membranous adhesions, and the incidence of intestinal obstruction will become smaller. In Chinese medicine, it takes years to accumulate vital energy after a caesarean section, which in a way emphasizes the role of quiet recuperation and waiting for adhesions to relax.