Diverticulitis is an acute primary inflammation of colonic pseudodiverticula and their surrounding soft tissue structures, which may result in severe abdominal and septic complications.
In case of suspected acute diverticulitis, diagnostic work-up aims to classify the disease in order to recommend the proper treatment protocol. This step is essential because the treatment options range from watchful waiting to emergent surgery.
The indication for surgery depends on the clinical picture of the diverticulitis, the risk of recurrence, subjective impairment of the patient, comorbidities, and medication. The response of nonsurgical treatment should also be taken into account.
Acute uncomplicated diverticulitis
The characteristic clinical signs of diverticulitis including changed laboratory findings, but without complications (phlegmon, abscess, fistulation or perforation) on imaging, suggest the diagnosis of acute uncomplicated diverticulitis. Closely monitored nonsurgical treatment is the first-line option here because these patients become asymptomatic after a short time and have a low risk of recurrence [13, 14, 29, 45]. Thus, there is no indication for elective surgery after the symptoms have abated [13, 36, 43]
In case of persistent complaints or worsening symptoms despite adequate treatment, the initial diagnostic work-up including imaging should be repeated in order to detect previously unrecognized or new complications and to adapt the treatment protocol to the recommendations in complicated diverticulitis.
While an antibiotic regimen in acute uncomplicated diverticulitis is not mandatory, the current German guideline S2k on diverticular disease/diverticulitis [34] recommends it for patients at risk for recurrence and complications.
- Arterial hypertension
- Chronic kidney disease
- Immunosuppression
- Allergic disposition
- Collagenosis
- Vasculitis
Depending on the risk profile of these patients surgery may still be indicated despite successful conservative treatment [2, 9, 10, 19, 49]. This is because post-transplant at patients and those otherwise immunocompromised have a significantly higher mortality than the normal population by up to 25%. In addition the risk of perforation is increased 2.7-fold [8].
The literature is divided regarding surgery in phlegmonous diverticulitis (type 1b). After successful nonsurgical treatment only few patients relapse despite the fact that the pathophysiology suggests a microperforation [17]. Therefore, no general recommendation for surgery may be made for this population. The current German, Anglo-American and Dutch guidelines reflect this course of action [5, 6, 34, 38].
Afebrile acute uncomplicated diverticulitis without leukocytosis, guarding, and fecal obstruction, and without evidence of perforation or complicated diverticulitis, but only slightly elevated CRP, may be treated on an outpatient basis. Adequate compliance, sufficient fluid and food intake and close medical follow-up, however, are mandatory [20,40]. One critique of the above trials is that all patients underwent an antibiotic regimen.
Acute complicated diverticulitis
Paracolonic abscess formation and free perforation are signs of acute complicated diverticulitis. When manifesting with the clinical picture of acute abdomen free-air perforation is an emergency and must to be treated by emergency surgery [28, 29, 34, 47].
Patients with complicated diverticulitis should be hospitalized, even if there is no free-air perforation with the clinical picture of acute abdomen. However, the initial treatment should be conservative [6, 11]. Unsuccessful clinical result within 72 hours suggests persistent inflammation, and therefore urgent (within 48 hours) sigmoidectomy should be considered [34]).
Paracolonic abscesses, fistulas, stenoses
Imaging demonstrates paracolonic abscess in about 15% of patients with acute complicated diverticulitis [20]. If the abscess is > 5cm, percutaneous interventional drainage, accompanied by antibiotics, may be attempted to avoid emergency surgery [12, 17, 44].
The data is incomplete regarding the question of whether elective surgery after successful conservative therapy of acute complicated diverticulitis is justified. However, histopathologic studies demonstrate persistent structural changes after paracolonic abscesses [26]. Furthermore, approximately 50% of patients develop secondary complications and about 40% relapse [3, 4]. Risk factors of these sequelae of paracolonic abscesses include [24]:
- Positive family history of diverticulitis
- Length of affected bowel segment > 5cm
- Presence of retroperitoneal abscess
In such cases elective surgery after inflammation has abated should be considered.
Elective surgery in bland conditions may also be considered if fistulas or clinically significant colonic stenoses develop after successful conservative therapy. Especially fistulas in the urogenital tract should be treated electively because they bear the danger and risk of urosepsis [21, 46].
Chronic recurrent diverticulitis
In recent decades, the recommendation for an elective sigmoidectomy depended on the number of experienced episodes: Resection after the second episode [33]. The recommendation by T. G. Parks goes back to 1969 [37]. He wrongly believed that the second episode increased the risk of complications and decreased the success of nonsurgical treatment. Parks based his studies on 40-year old data on the spontaneous course of diverticulitis, obtained under the clinical conditions at that time.
Current data show that an increase in the frequency of episodes does not necessarily correlate with an increase in septic complications [34]. Perforations, which require emergency surgery, also happen either as the primary event of diverticulitis or after the first episode. Therefore, prophylactic surgery after the second episode, as recommended until a few years ago, is no longer justified.
The indication for surgery in chronic recurrent diverticulitis should be evaluated individually, taking into account
- Complaints
- Risk factors
- Age
- Severity of disease
- Personal situation and comorbidities
The operation primarily aims to eliminate the complaints caused by the disease. There must be a careful risk-benefit analysis and the goals defined clearly because surgery will not prevent septic complications, emergency surgery and colostomy. Morbidity and mortality will not decrease either.
Diverticular bleeding
The management of gastrointestinal bleeding first relies on the entire range of diagnostic and therapeutic endoscopy [1, 16, 27, 30, 35]. Emergency endoscopy is the treatment choice [23].
Angiography (possibly CT-angiography) should be performed, if endoscopy cannot identify the source of the bleeding active at the time of the examination.
Surgery is indicated for persistent bleeding not controllable by endoscopy or intervention. The urgency depends on the cardiovascular situation, the intensity of bleeding and the present risk profile.
Localizing the bleeding is essential because this allows targeted surgery. If the source of the bleeding cannot be localized, it cannot be assumed to be in the sigmoid. In these rare cases of unsuccessful bleeding localization a subtotal colectomy with ileostomy must be considered. Since “blind” segmental resections of the colon bear a high risk of persistent recurrent bleeding, they should not be performed. If the location is uncertain, subtotal colectomy is the treatment of choice [15].
Recurrent clinically significant diverticular bleeding (e.g., drop in Hb >2g/dL, shock) without any option to decrease the risk of renewed recurrent bleeding by an interventional procedure should undergo early elective surgery after individual risk-benefit assessment [34].
Patients with self-limiting diverticular bleedings and those after successful interventional treatment should not undergo surgery [34].
Time of operation
The American Society of Colon and Rectal Surgeons recommends elective resection 6–8 weeks after the beginning of symptoms [38]. The Danish and Dutch guidelines do not specify the best time for surgery [5, 6]. Resections in the phase after 6 – 8 weeks when inflammation has abated demonstrate less anastomotic failures, impaired wound healing and conversion to open surgery (“early-elective” surgery) [39].
Technical aspects of sigmoidectomy
The goal of elective sigmoidectomy surgery is the removal of the complete sigmoid and construction of a tension-free anastomosis at the upper rectum.
There is no correlation between the number of residual diverticula in the remaining colon and the risk of recurrent diverticulitis. Therefore, there is no indication to extend the resection [48]. The level of the distal transection has a significant impact on recurrence: The risk of recurrence decreases significantly if the level of transection is at the distal rectum [7].
The splenic flexure does not necessarily need to be mobilized if the descending colon is long enough. According to some authors the risk of anastomotic failure and sexual dysfunction is minimized by sparing the inferior mesenteric artery [25].
Unless there are specific reasons for open surgery (e.g., patient demand, lack of surgical expertise), laparoscopic or laparoscopically-assisted resection is preferred [2]. The same also applies to complicated and recurrent sigmoid diverticulitis [25].
The direct comparison of open surgery versus laparoscopic sigmoidectomy for the short-term postoperative course favors laparoscopy in terms of lower blood loss, faster recovery, shorter length of stay in hospital, faster onset of intestinal motility, overall lower morbidity, and lower overall costs [18, 22]. In terms of quality of life and complications 6 months after surgery, however, the laparoscopic procedure did not evidence any superiority over the open procedure [31].