Rectal injury

　　One, Etiology

　　1, Open injuries are more common in wartime, especially in firearm injuries of the lower abdomen and perineum, and are often multiple organ injuries, often accompanied by soft tissue injury and defect of the perineum. In peacetime, it is mainly seen in knife stab wounds or falls from a height, sitting on a sharp object, or piercing the rectum to cause injury through the perineum or anus. There are also cases of rectal perforation due to paraphilic love or mischief with foreign objects inserted into the anus.

　　Sometimes, one lower limb is pulled extremely backward and outward by a strong external force, and when rotated, the perineum is torn and the anal canal and rectum are involved. The characteristic of this kind of injury is that there is a large wound in the perineum, and there are urethral or vaginal lacerations.

　　2, Closed injuries are mostly caused by traffic accidents, falls, crushes, collisions, and碾压for reasons such as. One is due to pelvic fracture displacement causing the levator ani muscle to contract and tear the rectum or fractured fragments to puncture the rectum; the other is due to a blunt force instantly compressing the abdomen, causing the gas in the sigmoid colon to rush into the rectum, and due to the anus being in a closed state, the rectum becomes a blind loop. The Rosenberg experiment proves that a pressure of 20.5 kg/cm2 can cause the intestinal wall to rupture into the rectal space without peritoneal coverage. The former injury is severe, often accompanied by urethral injury and traumatic hemorrhagic shock; the latter has a large rupture and severe contamination.

　　3. Iatrogenic injuries: pelvic surgery, perineal surgery, and vaginal surgery operations may inadvertently injure the rectum. Procedures such as rectal irrigation, barium enema, rectoscopy, or sigmoidoscopy for examination or treatment (such as high-frequency electrocoagulation, laser, etc.) may also cause rectal perforation.

　　2. Pathogenesis

　　Pathological changes vary with the degree of injury, the nature of the injurious object and the method of action, the location, extent, time, and whether there are injuries to other organs. Mild injuries may only involve mucosal tears and muscle layer splits, while severe injuries may have complete intestinal wall rupture and extensive sphincter injuries. If there are injuries to large blood vessels and the pre-sacral venous plexus, massive bleeding and shock may occur. Upper and middle one-third injuries of the rectum often accompany purulent peritonitis; lower one-third injuries are prone to cause perirectal and anal canal space infections, such as pelvic cellulitis, posterior rectal space, and ischiorectal pouch infections. Due to the large size of these spaces, along with mixed anaerobic bacterial infections and continuous contamination of feces from the intestines, it can cause extensive necrosis, severe sepsis, and bacteremia, even death. Rectal injuries can also lead to rectovesical fistula, rectovaginal fistula, and extrarectal fistula. Anal canal injuries can cause anal stricture and incontinence of the anus.

　　Fecal overflow after rectal rupture is prone to cause infection in nearby areas. Due to the deep and hidden position of the rectum, along with the good protection of the pelvis, it is rarely injured. Once injured, since the rectum is often empty or even if there is feces, it is not easy to overflow from the perforation, the inflammation progresses slowly, and symptoms are hidden, making them easy to overlook. However, the bacteria in the injured area are diverse and dense, reaching up to 10^16/L, which is highly prone to cause severe abdominal or perirectal space infections.

　　Due to differences in the location and severity of the injury, the duration of perforation, the size of the perforation, and the degree of fecal contamination of the abdominal cavity, the clinical manifestations may vary. Common symptoms include:

　　1. Shock:Hemorrhagic shock caused by rectal injuries is relatively common, and this bleeding is often difficult to control. The incidence of shock in isolated rectal injuries is 11%, while the incidence increases to 31.7% in cases with associated injuries, especially when associated with pelvic injuries, which are more severe.

　　2. Peritonitis:Intraperitoneal rectal injuries inevitably accompany signs of peritonitis, and the severity is closely related to the extent of the injury, the amount of intestinal content, and the condition of associated injuries. A single perforation in a rectal injury without contents is not typically symptomatic.

　　3. Peritoneal Cellulitis:Extraperitoneal rectal injuries do not show peritonitis symptoms, abdominal pain is not severe, but infection is prone to spread along the perirectal and anal canal spaces, causing pelvic cellulitis, posterior rectal space infection, ischiorectal pouch infection, and other symptoms, hence the severity of systemic infection symptoms is serious.

　　4. Associated Injuries:Due to the different types of associated injuries, the clinical manifestations of rectal injuries may vary greatly, even to the extent that the rectal injury is missed while the associated injury is predominant, such as when associated with bladder or urethral injuries, which can manifest as blood and (or) urine mixed with feces.

　　5. Precautions

　　(1) Contraindications to enema: Regardless of the type of examination, it is absolutely forbidden to inject air, water, barium, or other substances into the anal canal for suspected rectal injury to prevent the accelerated spread of infection.

　　(2) Pay attention to the characteristics of penetrating injuries: In cases of rectal penetrating injury, the number of perforations is usually 'even', that is, if there is a perforation on one side, there is also a perforation on the opposite side. The examination should not ignore this.

　　(3) Prevent missed diagnosis: Rectal injury is easily missed under the following conditions:

　　① In cases with a large number of injured personnel or those with multiple perforating injuries, rectal injury is easily missed, especially when there is only a small perforation in the perineum.

　　② In cases of shock and multiple fractures with malalignment, the diagnosis of rectal injury is easily affected, and in a few cases, sigmoidoscopy may be needed to detect it.

　　③ Injuries below the peritoneal fold and above the levator ani, due to mild early symptoms, they are easily overlooked, but if there is a clear history of trauma, diagnosis is not difficult.

　　(4) Pay attention to rectal injury information:

　　① Closed injuries can usually be diagnosed by careful analysis and examination of the history of trauma and clinical manifestations. The clinical manifestations vary according to the site, degree, and timing of seeking medical attention. After admission, the patient's condition should be quickly estimated, and attention should not only be paid to the abdomen and pelvis but also to other parts of the body for potential associated injuries.

　　② In cases of weapon injuries, the entrance, exit, size, direction, route, and time of injury, as well as the patient's position and posture at the time of injury, can often suggest whether there is a rectal injury. The presence of blood flowing out from the anal canal after injury is a strong indication of rectal injury. If there is abdominal pain and peritoneal irritation, it indicates an intraperitoneal rectal injury. If urination is not possible or blood and feces are present in the urine after injury, or urine flows out from the anal canal, it indicates bladder or urethral injury. Any open wound in the perineum, sacral tail, buttocks, thigh, or lower abdomen, if feces overflow from the mouth, should be considered as a rectal injury. If there is a traumatic shock in the case of rectal injury, it is often accompanied by injuries to other organs, such as pelvic fracture, major vascular injury, retroperitoneal hemorrhage, and extensive soft tissue injury, etc.

　　Postoperative prevention:

　　1. Maintain unobstructed gastrointestinal decompression until the intestinal function recovers and stops.

　　2. Continue to use a sufficient amount of broad-spectrum antibiotics and metronidazole, an anaerobic drug.

　　5. Ensure unobstructed drainage, proper placement time, rectovesical陷凹drainage can be removed after 2 to 4 days; remove the nearby drainage tube after mending or anastomosis until it can be confirmed that the wound has healed and will not leak; pre-sacral drainage starts on the third day after surgery, gradually pull out a little each day, and it usually takes about 7 to 10 days to completely remove it. It must be noted that:

　　(1) Whether within or outside the abdominal cavity, the drainage should not be placed at the rupture or sutured area to prevent the formation of fistulas.

　　(2) The drainage should not be removed too early or too quickly, but it should not be left in place for too long either, to prevent the formation of sinus tracts.

　　(3) When the patient has symptoms such as high fever and infection, check whether the drainage is unobstructed or whether there is infection outside the drainage area, and correct it in time or make a new incision for drainage.

　　4. Strengthen perineal care: Clean the urethral orifice, vagina, and anus in time, remove secretions, and use alcohol for wiping.

　　5, Management of the catheter: If there is no bladder and urethral injury, it can be removed as soon as possible to prevent infection. If there is a bladder or urethral injury, it should be removed after the wound of the bladder and urethra heals.

　　6, Strictly observe the condition, and detect and deal with postoperative complications in a timely manner.

　　7, Careful protection of the stoma should be ensured, and the flowing stool or secretion should be cleaned up in time, and the surrounding skin should be protected. The colostomy should not be closed prematurely, with 6 weeks to 3 months being the best.

　　1, Rectal examination:The following conditions in clinical practice should all be routine rectal examination

　　(1) Anal canal injury caused by violence, such as collisions, falling injuries;

　　(2) Anal puncture injury;

　　(4) Pelvic compression injury, kick injury in the lower abdomen;

　　(5) Patients with rectal bleeding after injury, rectal examination not only can find the size and number of the wound, but also can judge the condition of anal sphincter injury, providing reference for treatment. The finger cover during rectal examination often has blood stains or urine. If the injury site is low, the opening can be felt, and swelling and tenderness in the wound area can be diagnosed. The positive rate can reach 80%.

　　If the digital examination is negative and there is still a suspicion of rectal injury, rectaloscopy can be performed under the condition of the injury, but it is not routine. Abdominal X-ray film, as well as anterior, posterior, and lateral pelvic films, are helpful for diagnosis.

　　2, Vaginal examination:Digital rectal examination in married women suspected of rectal injury is also helpful for diagnosis, as it can touch the破裂 opening on the anterior wall of the rectum and clarify whether there is a concurrent vaginal rupture.

　　3, Endoscopic examination:For those with negative digital rectal examination, rectal or sigmoidoscopy examination can be performed to detect rectal rupture that was not reached or missed by digital rectal examination, as it can directly visualize the injury site, extent, and severity, often providing the basis for treatment.

　　4, X-ray examination:It is also an indispensable important means of diagnosing rectal rupture. The detection of free gas under the diaphragm suggests intraperitoneal rectal rupture; by the pelvic image, the condition of pelvic fracture and the location of metallic foreign bodies can be understood. Bubbles seen in the soft tissues of the pelvic wall suggest extraperitoneal rectal rupture.

　　Rectal imaging, although helpful for diagnosis, can aggravate contamination and spread infection, with more disadvantages than advantages, so it should be listed as a taboo.

　　5, Routine blood test:Leukocyte count and neutrophils increase.

　　After surgery and radiotherapy, chemotherapy, patients' bodies will be very weak and immunity will decrease. At this time, it is necessary to enhance physical fitness, improve the ability to resist diseases, prevent recurrence, adjust the whole body status, eliminate toxins, and take traditional Chinese medicine such as anticancer Pingwan, Zhenxiang Capsules, etc.

　　Protein:Excessive intake of animal protein means consuming more meat and fats, fewer fiber-rich foods, which can indirectly affect the opportunity of cancer occurrence. In Western and highly industrialized countries, meat (especially red meat) is the main food, and the meat cooked at high temperatures produces heterocyclic amines, which are carcinogens and lead to the occurrence of colorectal cancer. It is recommended that those who love to eat meat reduce the amount of red meat (beef, pork), and increase fish and chicken.

　　Once diagnosed with rectal rupture, emergency surgery is required. Every delay of 4 hours increases the mortality rate by 15%.

　　1. Preoperative preparation

　　(1) Open the veins, rapidly and adequately expand the volume to correct shock.

　　(2) Use of broad-spectrum antibiotics and metronidazole, an anti-anaerobic drug.

　　(3) Routine insertion of a nasogastric tube for gastrointestinal decompression.

　　(4) Routine placement of a urinary catheter to empty the bladder for ease of surgical operation.

　　2. Key points of surgery

　　(1) Incision: The midline or left paracentral incision of the lower abdomen is selected.

　　(2) Treatment procedures: Hemostasis should be given top priority to save life. The rectal rupture should be clamped with an intestinal clamp, and a large salt water sand pad should be used to separate it from the peritoneum and other organs. A comprehensive exploration of all abdominal organs is conducted, and all abdominal injuries are treated according to the principle of treating the serious first and the light later. Finally, rectal injury is treated.

　　(3) Selection of surgical methods:

　　① Abdominal rectal injury repair: Indications include mild abdominal contamination, no obvious inflammation, single injury, rupture less than 2 cm, fresh rectal laceration or stab wound.

　　② Abdominal rectal injury repair combined with sigmoid colostomy: Although the rectal injury is not severe, in the following situations, a sigmoid colostomy should be performed routinely after rectal repair to make the suture site easier to heal: A. Complicated with shock. B. Fractures of the pelvis with injury to abdominal and pelvic organs. C. The rectum is full or abdominal contamination is severe. D. Delayed treatment for more than 4 hours; E. Extraperitoneal rectal rupture.

　　③ Abdominal rectal resection, distal anastomosis closure, and proximal colostomy (Hartmann's operation): Indications include severe rectal rupture, extensive injury range, unable to repair or severe abdominal contamination, severe intestinal wall inflammation and edema, not suitable for suture, especially blast injuries. First, the superior rectal artery is ligated, the rectum is freed, and the intestine is transected below the injury site, and the distal end is sutured and closed. After resecting the injured intestine, the proximal colonic end is brought out through another incision on the left abdominal wall and a colostomy is performed. After the patient recovers, the colostomy colon is to be reimplanted into the abdominal cavity and anastomosed with the rectal stump at a later time.

　　④ Abdominoperineal sigmoid colostomy and pre-sacral drainage: Indications include: A. Extraperitoneal rectal rupture. B. Severe contamination of rectal perirectal spaces. C. Fractures of the pelvis with injury to other pelvic organs. D. Lacerations of the perineum or anal canal. First, an abdominal exploration is performed to treat injuries to abdominal organs, and a sigmoid colostomy is performed. As for the treatment of extraperitoneal rectal rupture itself, unless debridement reaches the rupture site and inversion suture can be performed after trimming, it is not necessary to perform it specifically. Because this repair is sometimes very difficult, and even if it is勉强修补，also often not satisfactory. As for the contamination of feces, it mainly depends on rectal lavage. Treatment should be given to injuries to pelvic organs, such as urethral rupture repair and vaginal laceration suture. Incisions in the perineum and anal canal should be debrided and repaired. Finally, pre-sacral drainage is performed. To avoid injury to the anal canal and rectal ring and the occurrence of fecal incontinence, an elliptical incision should be made on one side of the coccyx. To ensure unobstructed drainage, the coccyx can be resected. To stop bleeding, even part of the sacrum can be resected. Pay attention to make sure that the drainage material is placed slightly below the rectal rupture. Pre-sacral drainage is very important, and it is one of the key measures for the treatment of extraperitoneal rectal rupture, which can reduce the infection rate by 50%.

　　The common feature of the above ②, ③, and ④ three surgical methods is that they all add sigmoid colon stoma surgery. This is not a trivial matter, directly related to the success or failure of the operation and the safety of the patient, and is one of the essential safe and stable key measures for dealing with severe rectal injury. Its disadvantage is that the patient's hospital stay is long, the psychological burden is heavy, and a second laparotomy is required to close the fistula.

　　⑤ Preventive intestinal exteriorization: How to achieve both safety and stability while minimizing the need for a second laparotomy has always been a key research topic for trauma surgeons. In recent years, the preventive intestinal exteriorization designed can better solve some problems, allowing a considerable number of patients with rectal rupture to avoid the suffering of colostomy and second laparotomy. It is suitable for severe injuries, light contamination, unable to undergo primary repair, and rectal injuries located above the peritoneal reflexion. For local rectal injury, debridement and suture or resection and end-to-end anastomosis of the damaged rectum with sigmoid colon double-lumen stoma surgery are performed. The exteriorized sigmoid colon is not opened after the operation, and after 3 to 5 days when the patient's bowel sounds recover and gas is passed, a sterile oil sand strip or silicone tube is passed through the mesenteric hole of the exteriorized sigmoid colon, the suture between the exteriorized intestinal tube and the abdominal wall is removed, the exteriorized intestinal tube is gently returned to the abdominal cavity, and the oil sand strip or silicone tube is fixed on the abdominal wall, and a sterile dressing is applied locally. Instruct the patient to eat and observe for 2 to 3 days. If there are no abnormalities, the oil sand strip or silicone tube is removed, and the abdominal wall at the stoma site is sutured in a second stage. If it is found that the repair or anastomosis fails, the exteriorized sigmoid colon is brought out of the abdominal wall again with the oil sand strip or silicone tube, sutured and fixed, and the stoma is opened.

　　(4) Debridement: Debridement should be thorough, and lavage should be sufficient. Especially for firearm injuries, the wound is small, the sinus is wide, the local tissue damage is severe, and it is possible to bring in soil, clothing, and fabric fragments into the wound channel, and there is often fecal contamination. Therefore, it is necessary to thoroughly debride along the wound channel, remove all foreign bodies, feces, bone fragments, clots, and necrotic tissue. And use a large amount of normal saline (at least more than 5000ml) to thoroughly lavage the peritoneal cavity, retroperitoneal space, and wound channel.

　　(5) Drainage: Ensure that the drainage is unobstructed and effective. For intraperitoneal rectal rupture, in addition to repairing, anastomosing, or sealing the residual ends near the wound and placing double-lumen drainage tubes, it should be routine to place double-lumen drainage tubes in the rectovesical陷凹. Pay attention that the drainage tubes should not be led out from the original wound or incision, and a separate incision should be made for the drainage. For extraperitoneal rectal rupture, pre-sacral drainage should be performed.

　　(6) Rectal lavage: It should be routine to clear the accumulated feces in the rectum, thoroughly lavage the rectum, and as much as possible to clear the bacteria in the intestinal lumen to prevent further contamination, which is crucial for severe rectal rupture. It is one of the three key measures for the treatment of extraperitoneal rectal rupture, along with sigmoid colon anastomosis and pre-sacral drainage. None of the three can be omitted. Simply creating a colostomy without performing rectal lavage and pre-sacral drainage is bound to lead to the secondary formation of rectal abscesses, while simply draining without creating a stoma and lavaging the rectum will leave various rectal fistulas, such as vesical fistula, vaginal fistula, and skin fistula, etc.

　　Rectal irrigation is simple and easy to operate. A disinfected rectal tube can be inserted from the anus to the distal part of the sigmoid colon for irrigation, or a catheter can be inserted into the distal end of the colostomy for downward irrigation. Warm saline is preferred. Pay attention not to apply too much pressure. If the feces in the rectum are dry, assistance is needed to dig them out. The irrigation must be thorough and sufficient until the rectum is completely clean and the effluent is clear.

　　3. Postoperative Management

　　(1) Keep the gastrointestinal decompression unobstructed until the intestinal function recovers and stop using it.

　　(2) Continue to use a sufficient amount of broad-spectrum antibiotics and metronidazole, an antibiotic against anaerobic bacteria.

　　(3) Ensure the patency of the drainage, and place it properly. The rectovesical sinus drainage can be removed after 2 to 4 days; the nearby drainage tube after repair or anastomosis should be removed when it can be confirmed that it has healed and will not leak; the pre-sacral drainage starts on the third day after surgery, and a little is pulled out each day until it is completely removed, which usually takes about 7 to 10 days. It must be noted: ① Whether inside or outside the peritoneum, the drainage should not be placed at the rupture or sutured area to avoid the formation of fistula. ② The drainage should not be removed too early or too quickly, but also should not be inserted for too long, leading to sinus formation. ③ When the patient has symptoms such as high fever and infection, check whether the drainage is patent, or whether there is infection outside the drainage area, and correct it in a timely manner or make a new incision for drainage.

　　(4) Strengthen perineal care: Clean the urethral orifice, vagina, and anus in time, remove the secretion, and can be wiped with alcohol.

　　(5) The management of the catheter: If there is no bladder or urethral injury, it can be removed as soon as possible to prevent infection. If there is bladder or urethral injury, it should be removed after the bladder or urethral wound has healed.

　　(6) Strictly observe the condition, and discover and handle postoperative complications in a timely manner.

　　(7) The stoma should be protected properly, and the excrement or secretion should be cleaned in time, and the surrounding skin should be protected. The colostomy should not be closed prematurely, with 6 to 3 months being the best.