CREDIT INFORMATION

To earn credit you must review the article and complete the test with a score of 70% or higher.

CME Credit Hours: 1 AMA PRA Category 1 Credit(s)™

Release Date: October 1, 2026
CME Expires: October 1, 2029

Accreditation

The American Society of Colon and Rectal Surgeons (ASCRS) is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education (CME) for physicians.

Successful completion of this CME activity, which includes participation in the evaluation component, enables the learner to earn credit toward the CME of the American Board of Surgery’s Continuous Certification program. It is the CME activity provider’s responsibility to submit learner completion information to ACCME for the purpose of granting ABS credit.

Designation

The American Society of Colon and Rectal Surgeons (ASCRS) designates this enduring activity for 10 AMA PRA Category 1 Credit(s)™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Financial Disclosures
The ASCRS Continuing Education Committee selects the articles from the DC&R Journal each month and creates the evaluation questions. The committee member disclosure listing is on the landing page for this content.

This article was published in Diseases of the Colon and Rectum October 2026 issue.

DEFINITIONS

These guidelines will focus solely on left-sided diverticulitis. The terms episode, uncomplicated and complicated diverticulitis, symptomatic uncomplicated diverticular disease, and recurrent diverticulitis are used throughout this document. This document uses the term “episode” to refer to a discrete occurrence of acute diverticulitis. This can also be referred to as “flare,” “attack,” or “bout.” For purposes of this guideline, complicated diverticulitis is defined as diverticulitis associated with a fistula, abscess, stricture, obstruction, or an uncontained perforation with a systemic inflammatory response. Micro perforation

with small amounts of contained extra luminal gas, in the absence of a systemic inflammatory response, is not considered complicated diverticulitis. Uncomplicated diverticulitis is defined as diverticulitis that is not associated with any of the above features. [1],[2],[3]

The term recurrent diverticulitis refers to discrete episodes of diverticulitis with an interval of at least 60 days of no symptoms between episodes. [2],[3]

STATEMENT OF THE PROBLEM

Approximately 5% to 10% of patients with diverticulosis may develop acute diverticulitis, [1]with the risk increasing with age. [2],[3]

From 2000 to 2008, the prevalence of hospitalization for diverticulitis increased from 74.1 of 100,000 in 2000 to a peak of 96.0 of 100,000 in 2008. Currently, 452,151 emergency department visits and 179,465 hospitalizations occur annually for acute colonic diverticulitis in the United States. National costs for hospitalizations with a principal diagnosis of acute diverticulitis totaled >$8.9 billion annually. [4]

As our understanding of diverticulitis has evolved, so have recommendations for the clinical management of these patients. Patients with diverticulitis are increasingly being treated as outpatients. Rates of hospital admission after emergency department evaluation for diverticulitis dropped from 58% in 2006 to 47% in 2013. [5]In addition, fewer patients are undergoing emergency colectomy. [5] Concurrently, there has been an increase in both elective and laparoscopic surgery in the management of diverticular disease. [6],[7]

This guideline summarizes the changing treatment paradigm for patients with left-sided diverticulitis. We do not address diverticular bleeding. Although diverticular disease can affect any segment of the large intestine, we will focus solely on left-sided disease, as this is the predominant presentation in the Western Hemisphere. Bowel preparation, enhanced recovery pathways, and prevention of thromboembolic disease, although relevant to the management of patients with diverticulitis, are beyond the scope of these guidelines and are addressed in other ASCRS clinical practice guidelines. [8],[9],[10]

METHODOLOGY

These guidelines were built on the previous ASCRS “Clinical Practice Guideline for the Treatment of Left- Sided Colonic Diverticulitis,” published in 2020. [11]

A comprehensive search was conducted in PubMed (NLM), Embase (Ovid), Web of Science, and Cochrane Library (Wiley) for studies with human subjects published from January 1, 2019, to February 6, 2026. The search strategy was developed with assistance from a health sciences research librarian and used a combination of subject headings and keywords to find primary literature on diverticulitis. Retrieved publications were limited to the English language and adult patients. For full search strategies, see Appendix 1 at https://links.lww.com/DCR/C649. Directed searches for the embedded references from the primary articles were also performed in certain circumstances. The initial search generated 3190 eligible studies, and after removing 987 duplicates, 2203 studies were screened for initial inclusion. Abstracts were screened for relevance, leaving 104 studies that each underwent full-text review by 7 coauthors, with all conflicts resolved by the first author. Following full-text review, 250 studies were excluded; 160 studies were considered for inclusion in the final article (Fig. 1). Abstract and full-text screening was ^F1 performed using Covidence systematic review software. [12] Prospective, randomized controlled trials (RCTs) and meta-analyses were given preference, but in the absence of higher-level evidence, peer-reviewed observational studies and retrospective studies were included.

CERTAINTY OF EVIDENCE

The final grade of recommendation was performed using the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) methodology system. [13]

The certainty of evidence reflects the extent of our confidence in the estimates of effect. Evidence from RCTs start as high certainty, and evidence derived from observational studies start as low certainty. For each outcome, the evidence is graded as high, moderate, low, or very low (Table 1). The evidence can be rated down for risk of bias, inconsistency, indirectness, imprecision, and publication bias. The certainty of evidence originating from observational studies can be rated up when there is a large magnitude of effect or dose–response relationship. Per GRADE methodology, recommendations are labeled as “strong” or “conditional.” All statements with strength of GRADE recommendations are stated in Table 2. Table 3 summarizes the new, updated, and excluded recommended clinical practice guidelines compared with the 2020 guidelines. Recommendations formulated by the subcommittee were reviewed by the entire Clinical Practice Guidelines Committee. When the agreement was incomplete regarding the evidence base or treatment guideline, consensus from the committee chair, vice chair, and 2 assigned reviewers determined the outcome. Members of the ASCRS Clinical Practice Guidelines Committee worked in joint production of these guidelines from inception to final publication. The entire Clinical Practice Guidelines Committee reviewed recommendations formulated by the subcommittee. Final recommendations were approved by the ASCRS Executive Council and peer-reviewed in Diseases of the Colon and Rectum Each ASCRS Clinical Practice

Guideline is generally updated every 5 years. No funding was received for preparing this guideline, and the authors have declared no competing interests related to this material. This guideline conforms to the Appraisal of Guidelines for Research and Evaluation checklist. [14]

INITIAL EVALUATION OF ACUTE DIVERTICULITIS

1. The initial evaluation of a patient with suspectedacute diverticulitis should include a problem-specific

history and physical examination and appropriate laboratory evaluation. Strength of recommendation: strongbased on low-quality evidence. A focused history and physical examination should be performed, including previous diverticulitis attacks or abdominal symptoms, family history of diverticulitis and other colorectal disorders, previous colonoscopy, immunosuppression or chronic steroid use, and risk factors, such as poor fiber intake, obesity and smoking. Although diverticular disease demonstrates moderate familial been attempts to predict disease severity and recurrence using C-reactive protein (CRP), procalcitonin, and fecal calprotectin. [15],[16],[17]In a retrospective study of 350 patients presenting with their first episode of diverticulitis, CRP >150 mg/L significantly discriminated acute uncomplicated from complicated diverticulitis, and the combination of CRP >150 mg/L and free fluid on CT scan was associated with a significantly greater risk of mortality. [18] In a study of 115 patients, procalcitonin was able to discriminate between patients with uncomplicated (median value 0.05 µg/L) and complicated disease (median value median 0.13 µg/L) with sensitivity and specificity of 81% and 91%, respectively (p < 0.0001). [17]

Another study of 48 patients demonstrated that elevated fecal calprotectin was associated with diverticulitis recurrence. [16]A diagnostic prediction model differentiating uncomplicated diverticulitis from complicated diverticulitis was developed. Incorporating 3 parameters, abdominal guarding, CRP, and leukocytosis, this validated model had a 96% negative predictive value for detecting complicated diverticulitis. [19]Despite the baseline predictability and evaluation of response to treatment that specific inflammatory markers may provide, the true utility of these remains inconclusive in the current literature and remains insufficient to guide practice recommendations.

2. CT scan of the abdomen and pelvis is the most appropriate initial imaging modality in the assessment ofsuspected diverticulitis. Strength of recommendation:strong based on moderate-quality evidence. CT imaging with intravenous contrast is the standard tool to diagnose diverticulitis, assess disease location and severity, and help devise a treatment plan. Low-dose CT is highly sensitive and specific (95% for each) for diagnosing acute abdominal complaints, including diverticulitis and other causes that can mimic the disease. [20]CT findings associated with diverticulitis may include colonic wall thickening, fat stranding, abscesses, extra luminal gas and fluid, and findings suggestive of fistula. The utility of CT imaging goes beyond the accurate diagnosis of diverticulitis; the grade of severity on CT correlates with the risk of failure of nonoperative management in the short term and may predict long-term complications, such as recurrence, persistent symptoms, and the development of colonic stricture and fistula. [21],[22]Both length of involved colon >5 cm (HR 1.7; 95% CI, 1.3–2.3) and retroperitoneal abscess (HR 4.5; 95% CI, 1.1–18.4) have been associated with diverticulitis recurrence. Emerging evidence suggests that increased visceral adiposity measured on CT is associated with a higher risk of complicated and recurrent sigmoid diverticulitis, likely reflecting the proinflammatory effects of visceral fat, although optimal CT-based thresholds and their clinical utility remain incompletely defined. [23]

MEDICAL MANAGEMENT OF ACUTE DIVERTICULITIS

3. Immunocompetent patients with uncomplicated diverticulitis being managed as outpatients may initiallyand selectively be treated without antibiotics. Strengthof recommendation: strong based on high-qualityevidence. The pathophysiology of diverticulitis remains unclear. Although diverticulitis may progress to micro or macro perforation with resultant bacterial infection, it is increasingly believed to be an inflammatory process governed by varied genetic and environmental factors. [24]These challenges to the traditional theory of diverticulitis as a bacterial infectious process have prompted questioning of the role of antibiotics in the management of uncomplicated diverticulitis. Four randomized trials inform this ^AQ8 clinical question: DIABOLO (n = 528), AVOD (n = 556), Selective Treatment with Antibiotics for Noncomplicated Diverticulitis (STAND; n = 180), and DINAMO (n = 480), with each contributing perspective through variation in intervention design and study outcomes. [11],[25],[26],[27]

In both AVOD and DIABOLO, patients with imaging confirmed uncomplicated diverticulitis were randomly assigned to inpatient management with antibiotics or supportive care in an unblinded manner. [25],[28]No difference in primary outcome was observed in either AVOD (complication-free recovery at 12 months: antibiotics vs no antibiotics: 1 vs 1.9%; p = 0.30) or DIABOLO (median time to recovery from the index episode: antibiotics vs no antibiotics: 14 vs 12 days; p = 0.15). At 12 and 6 months, respectively, no differences in recurrence or the need for surgery were identified in either the AVOD or DIABOLO cohorts. Long-term follow-up of the AVOD (median, 11 years) and DIABOLO (median, 24 months) cohorts continued to show no difference in recurrence (antibiotics vs no antibiotics: AVOD: 31.3 vs 31.3%; p = 0.99; DIABOLO: 14.9 vs 15.4%; p = 0.89), complications (antibiotics vs no antibiotics: AVOD: 5.0 vs 4.4%; p = 0.74; DIABOLO: 3.3 vs 4.8%; p = 0.40), or need for surgery (antibiotics vs no antibiotics: AVOD: 7.1 vs 6.2%; p = 0.72; DIABOLO: 5.0 vs 9.0%; p = 0.09). [27],[29]Published in 2021, in the STAND trial, 180 patients with uncomplicated diverticulitis were randomly assigned to 7 days of antibiotics versus placebo. [30]The study showed no differences in the primary end point of hospital length of stay (antibiotic vs placebo: 40.0 vs 45.8 hours; p = 0.20) nor in the secondary end points of adverse events or 30-day hospital readmission. Also published in 2021, investigators in the DINAMO trial (n = 480) conducted a noninferiority, multicenter RCT of outpatient management with oral antibiotics versus outpatient management with supportive care. [26]Hospital admission, the primary outcome of the study, was required in 5.8% of patients in the antibiotic group compared with 3.3% of patients in the nonantibiotic group, which met the prespecified criteria for noninferiority (mean difference 2.58; 95% CI, 6.32 to −1.17). A meta-analysis of 1809 participants in AVOD, DIABOLO, STAND, and DINAMO showed a high degree of certainty that antibiotics have little to no impact on mortality, complicated diverticulitis, or need for surgery. [31]With a moderate degree of certainty, antibiotics showed little or no impact on readmission and recurrent diverticulitis. Regarding treatment location, DINAMO added to an existing meta-analysis of 19 trials (n = 2303; 1 RCT, 10 prospective, 8 retrospective) showing safe and cost-effective outpatient care for patients with uncomplicated diverticulitis provided that adequate follow-up is feasible. [32]

In the absence of antibiotic usage, supportive care in the AVOD, DIABOLO, DINAMO and STAND trials included nonnarcotic analgesics and intravenous hydration for admitted patients. None of the studies are proscriptive regarding a specialized diet in the acute setting for acute uncomplicated diverticulitis. Moreover, whether treating acute uncomplicated diverticulitis with or without antibiotics, a meta-analysis (n = 600) of 3 RCTs and 2 observational trials provides very low-level evidence to guide dietary modification for the treatment of acute uncomplicated diverticulitis, particularly with respect to fiber intake. [33]

Scrutiny of the inclusion and exclusion criteria for the above trials is critical to generalizing their findings. All 4 studies explicitly excluded immunocompromised and pregnant patients in addition to patients with concerns for a more acute presentation, such as peritonitis or 2 or more systemic inflammatory response criteria. Although not explicitly excluded, patients older than 70 years were poorly represented in the RCTs, making generalizability to this population limited. The mean age of participants across the 4 trials was the late 50s. All studies omitted patients with complicated diverticulitis, although DIABOLO did include 42 patients with pericolic abscesses <5 cm. Bolkenstein et al [34]evaluated 109 patients, including 39 patients from DIABOLO, with foci of extra luminal air within 5 cm of the affected colonic segment, of whom 48% were treated with antibiotics. Nine of 109 patients (8%) required either emergency surgery or percutaneous drainage. In the adjusted analysis, antibiotic therapy was not associated with treatment failure (OR 2.48; 95% CI, 0.43–14.40). However, more data are needed to determine the optimal management strategy for patients with foci of extra luminal air.

Route and timing of antibiotics have been investigated. A meta-analysis of 2 RCTs and 2 prospective case series (n = 355) revealed no difference in failure rate between oral and intravenous administration (oral vs intravenous: 6 vs 7%; OR 0.76; 95% CI, 0.33–1.78; p = 0.6). [35]A 2024 single-center noninferiority RCT (n = 118) comparing patients receiving oral versus intravenous antibiotics in the outpatient setting showed no difference in readmission, analgesic use, or GI function, further supporting the safety of oral antibiotics. [36]Duration of antibiotics has been evaluated via RCT (n = 106) showing no difference in treatment success between 4 and 7 days of antibiotics suggesting that short course antibiotics may be a safe option in immunocompetent patients. [37]

Antibiotics continue to play a role in managing uncomplicated diverticulitis in specific populations, particularly due to limited representation in RCTs and concerns about potential treatment failure. Immunocompromised patients, who are underrepresented in clinical trials, face a higher risk of complications and should be treated with antibiotics. For patients with acute uncomplicated diverticulitis, the risk of progression to complicated diverticulitis is ~5%. [38]Risk factors for progression include duration of symptoms longer than 5 days before presentation, presence of vomiting, CRP >140 mg/L, and baseline white blood cell count >15 × 10 [9],[38]cells/L. The presence of a fluid collection on baseline CT is also associated with an increased risk of progression to complicated diverticulitis. [39]Patients with one of these factors should be considered high risk and treated with a course of antibiotics.

4. Healthy diet, tobacco cessation, reduced meat intake,increased fiber intake, physical activity, and avoidanceof obesity may reduce the risk of diverticulitis. Strengthof recommendation: conditional based on moderatequality evidence. Large, population-level studies provide insight into the factors associated with an index case of diverticulitis. The US Health Professional Follow-up Study (n = 46,461 men) identified consumption of the “Western dietary pattern,” a diet high in red and processed meats, refined grains, sweets, French fries, and high fat dairy products, at the highest quintile to be associated with an increase in the hazard of selfreported diverticulitis (HR 1.55; 95% CI, 1.20–1.99), whereas consumption of the “prudent dietary pattern,” a diet high in fruits, vegetables, whole grains, legumes, poultry, and fish, to be associated with a decreased hazard of diverticulitis when consumed at the highest quintile (HR 0.74; 95% CI, 0.60–0.91). [40]Further analysis of the components of these dietary patterns has shown benefits to increased fiber consumption [41],[42]and decreased red meat intake with respect to decreased risk of diverticulitis. In female individuals, healthy diets are associated with a reduced risk of incident diverticulitis. [43]Physical exercise (high vs low physical activity; relative risk [RR] 0.76; 95% CI, 0.63–0.93) [44]is associated with a decreased risk of diverticulitis, whereas obesity (5 point increase in BMI associated with a 28% increase in diverticular disease; 95% CI, 1.18–1.40) [44]and smoking (active smokers [RR 1.36; 95% CI, 1.15–1.61]) [45]were associated with increased risk of diverticulitis. In numerous studies, consumption of nuts and seeds has not been shown to be associated with diverticulitis risk. [43],[46]Patients should be encouraged to adhere to an overall healthy diet to minimize the risk of diverticulitis.

It is important to note that such large, longitudinal, case–control studies examining risk factor exposures are highly subject to recall bias and to confounding and potentially collinear variables. Accordingly, the authors acknowledge that risk factors associated with diverticulitis development or recurrence may not be directly causative. Although conventional medical wisdom generally supports global benefits of a healthy diet, tobacco cessation, and obesity avoidance, the effects of risk factor modification as a diverticulitis treatment are uncertain.

5. Mesalamine, rifaximin, and probiotics are not typically recommended to reduce the risk of recurrentdiverticulitis. The combination of a dietary fiber supplement plus rifaximin may be of value in reducing symptoms and preventing recurrence of acute uncomplicateddiverticulitis. Strength of recommendation: conditionalbased on low-quality evidence. Given its anti-inflammatory properties, mesalamine has been studied to reduce the risk of recurrent diverticulitis. A Cochrane review, including 7 RCTs (n = 1805) identified no difference in recurrence rates between patients receiving mesalamine compared with those who did not (mesalamine vs no mesalamine: 31.3% vs 29.8%; RR 0.69; 95% CI, 0.43–1.09). [47]However, the authors noted that all included studies had an unclear or high risk of bias and deemed the level of evidence very low. [48]

As a poorly absorbed oral antibiotic with resultant effect on the fecal microbiota, [49]rifaximin has been studied to evaluate its role in reducing recurrent diverticulitis. A meta-analysis of 4 RCTs (n = 1660) evaluated fiber supplementation alone versus fiber supplementation with rifaximin for the reduction of recurrence in acute uncomplicated diverticulitis. [50]Fiber supplementation with cyclic rifaximin was effective in relieving symptoms with a pooled risk difference of 64% in the rifaximin groups versus 29% in the control group (95% CI, 24.5%–33.6%; p < 0.001). [51]

The incidence of acute uncomplicated diverticulitis while treated with fiber supplementation plus cyclic rifaximin was also reduced in the treatment arm although with a smaller effect size (Pooled risk difference 1.0 vs 2.8%; 95% CI, −3.4 to −0.57%; p < 0.001). The role of rifaximin without fiber supplementation, as well as the longterm (>1 year) preventive effect of rifaximin plus fiber supplementation on recurrent or complicated diverticulitis remains inconclusive.

A systematic review of 11 studies (7 randomized; n = 764) evaluated the role of probiotics in reducing the incidence of acute uncomplicated diverticulitis. [51]Studies used varied strains of probiotics and used treatment regimens that included a variety of other agents, including fiber, mesalamine, balsalazide, and beclomethasone. The data were too heterogeneous to draw meaningful conclusions. Data are insufficient to recommend probiotics in the treatment of diverticulitis either for symptom mitigation or to reduce the risk of recurrence.

6. Diverticular abscesses should be managed with antibiotics. Image-guided percutaneous drainage shouldtypically be considered for patients with an abscess size>4 cm or clinical deterioration. Strength of recommendation: strong based on moderate-quality evidence. Approximately 10% to 20% of patients with acute diverticulitis develop an abscess. [52]Given the nature of abscesses as bacterial infections, broad-spectrum antibiotics are indicated for treatment. Percutaneous drainage should supplement antibiotic therapy when feasible for larger abscesses (typically >4 cm) or in the setting of clinical worsening. Regardless of the nonoperative approach (antibiotics, percutaneous drainage or a combination), the overall success rate of nonoperative management for diverticular abscess is ~80% to 85%. Risk factors for failure of nonoperative management have included immune status, abscess location, abscess size, and the use of percutaneous drainage. [53],[54]In the Spanish DIPLICAB multicenter retrospective cohort study (n = 1395), the initial failure of nonoperative management for patients with diverticular abscess did not differ between immunosuppressed and immunocompetent patients (19.5% vs 13.5%; p = 0.08) although immunosuppressed patients had a higher mortality rate (15.1% vs 0.6%; p < 0.01). [55]Abscess size ≥5 cm was associated with emergency surgery in a Dutch multicenter retrospective study (n = 447; OR 2.96; 95% CI, 1.03–8.13), whereas abscess size ≥3 cm had a greater odds of treatment failure (composite outcome of complications, readmissions, persistent diverticulitis, emergency surgery, death, or need for drainage in the no-percutaneous drainage group; OR 2.05; 95% CI, 1.09–3.86). [56]In a Finnish study, diverticular abscesses <4 cm were successfully treated with antibiotics alone in 87% of cases. [57]

Thus, patients with larger abscesses have been associated with a higher risk of failure without drain placement and a higher risk of emergency surgery overall. However, in stable patients for whom percutaneous drainage is not technically feasible, a trial of nonprocedural management is reasonable, given high rates of observed success across large multicenter observational trials. In the immunocompetent cohort of the DIPLICAB study, emergency surgery was required in 13.5% (171/1001) of patients despite only 15.5% receiving percutaneous drainage and 63.7% having abscesses ≥3 cm. [55]Similarly, in the Dutch multicenter retrospective study, the need for emergency surgery was low among patients with diverticular abscess (8.9%; n = 40/447) despite only 25.7% receiving percutaneous drainage. [56]Emergency surgery within 30 days of diagnosis was more likely in the percutaneous drain group (13.9 vs 7.2%; p = 0.03) although patients receiving drainage had larger abscesses and more pelvic abscesses compared with pericolonic abscesses.

Although the management of a diverticular abscess is not stratified on location alone (pelvic vs paracolic), several retrospective studies have demonstrated distinct characteristics with pelvic abscesses, such as less often treatment success and higher recurrence rates with antibiotics alone, increased need for percutaneous drainage, increased risk of fistula to bladder, vagina and adnexa, and higher subsequent colectomy rates. [53],[54]Further data may guide which patients benefit from nonprocedural management compared with percutaneous drainage or early surgery.

Overall, patients with diverticular abscesses should be managed with antibiotics as first-line treatment, with percutaneous drainage added for larger abscesses, failure to resolve with antibiotics alone, or clinical deterioration. Although diverticulitis-specific data are limited, current evidence from studies of complicated intra-abdominal infections support a short course (~4–7 days) of antibiotics after successful percutaneous drainage and adequate source control of a diverticular abscess. [58]Furthermore, routine reimaging after percutaneous drainage of a diverticular abscess is not universally required and should be guided primarily by clinical response; repeat CT is generally reserved for patients with persistent symptoms, ongoing sepsis, uncertain source control, fecal drainage from the drain, or when drain removal is being considered despite concern for a residual cavity.

EMERGENCY SURGERY FOR ACUTE DIVERTICULITIS

7. Colectomy is advised for patients with diffuse peritonitis or failure of nonoperative management of acutediverticulitis. Strength of recommendation: strongbased on low-quality evidence. Nonoperative management of acute diverticulitis is successful in most hospitalized patients, with only 10% to 15% of patients requiring surgery. [59],[60],[61]In a review of 830,628 patients admitted with diverticulitis, only 10.1% required colectomy and 50% of the operations occurred within 2 days of admission. Diverticular abscess, sepsis, and multiple comorbidities were the highest predictors of failure of nonoperative management. Colectomy is indicated in patients who require control of the infection beyond percutaneous drainage. This typically includes patients who are acutely ill with multiquadrant peritonitis or systemic inflammatory response due to purulent or feculent peritonitis. In randomized trials of emergent resections, serious morbidity after emergency colectomy for diverticulitis ranged between 29% and 44.3%, and mortality rates of 3.9% to 25% were reported. [62],[63],[64],[65]In a national retrospective study evaluating complications after emergency colectomy for diverticulitis in 2214 patients, the overall 30-day operative mortality was 5.1%. Predictors of mortality included age more than 80 years, ASA Physical Status Classification System class 4 or 5, serum creatinine >1.2 mg/100 mL, and serum albumin <2.5 g/100 mL. Patients with 2, 3, or 4 of these predictors had a 30-day mortality rate of 10%, 22.9%, and 53.4%, respectively. [66]

8. Under appropriate conditions, restoration of bowelcontinuity with proximal diversion after colectomy foracute diverticulitis may be considered. Strength of recommendation: conditional based on moderate-qualityevidence. Hartmann’s procedure, involving sigmoid resection with end colostomy, has been the standard for surgical treatment of acute diverticulitis. However, long-term data support management with primary anastomosis. [65],[67],[68],[69],[70],[71],[72],[73]

The ColonPerf RCT (n = 62) and DIVERTI (n = 102) trials, despite limited accrual, demonstrated improved outcomes with primary anastomosis in patients with purulent and feculent peritonitis. Both observed no difference in morbidity or mortality, but significantly higher long-term stomafree rates (90% vs 57%, p = 0.005; 96% vs 65%, p = 0.0001). [72],[74]ColonPerfRCT ended early due to higher serious morbidity with Hartmann reversal (20% vs 0%). [72]In DIVERTI’s >9-year follow-up, 20% of Hartmann patients retained a stoma, versus none in the anastomosis group. Primary anastomosis also had lower incisional hernia rates (29% vs 52%) and better quality of life (QoL). [75]

The DIVA arm of the LADIES trial (n = 133) compared Hartmann’s procedure to primary anastomosis (with or without diversion). Stoma-free survival at 36 months was higher with anastomosis (92% vs 81%; HR 2.33, p < 0.0001). Morbidity (36% vs 48%) and mortality (11% each) were similar. Patients who underwent a Hartmann’s procedure had more parastomal hernias (16% vs 2%, p = 0.009). [68],[71] Primary anastomosis was more cost-effective (incremental cost-effectiveness: €–39,094 or $43,786 in 2019). [56]

Meta-analyses [65],[67],[69],[73]confirm these findings. One review of 382 patients across 4 RCTs [68],[71],[75],[76]showed lower surgical site infection rates (3.3% vs 11.3%) and higher stoma reversal rates (84% vs 64.5%) with primary anastomosis. A larger review of 1066 Hinchey III/IV patients found no differences in short- or long-term mortality, morbidity, or serious complications. [65]Leak rates were 6.2% (anastomosis) versus 1% (Hartmann stump). Stoma reversal was more likely with anastomosis (80.3% vs 62.1%; OR 2.62). No differences were found in combined morbidity/ mortality or in the feculent peritonitis subgroup analysis. They further reported an overall increase in expense of 74% to 299% higher cost with Hartman procedure.

These findings must be tempered with the acknowledgment that it is difficult to enroll emergent surgery patients in randomized trials. All the above trials failed to meet enrollment targets, suggesting that the results may not represent a “real world” setting. This statement describes “optimized conditions,” including normal hemodynamics, appropriate nutrition, absence of immunosuppression, and healthy bowel for the anastomosis. Should any of these factors be missing, an end colostomy may avoid extra time in the operating room and morbidity.

The role of diversion in these trials needs to be highlighted. In both the ColonPerfRCT and the DIVERTI trials, patients undergoing primary anastomosis were diverted proximally with either an ileostomy or colostomy. [72],[74]In the LADIES trial, 73% of patients randomly assigned to primary anastomosis underwent proximal diversion. [71]

Adoption of primary anastomosis has increased, from 3.9% (1998–2011) to 12.5% (2015–2019), per National Inpatient Sample data. [77],[78]Surgeon training and patient immunologic status also influence outcomes. A New York State study (n = 10 600 Hartmann vs 180 anastomosis) found higher mortality when non–colorectal surgeons performed primary anastomosis with proximal diversion (15% vs 7.4%, p < 0.001). [79]Immunocompromised patients were less likely to receive primary anastomosis (10.1% vs 43.1%). [80]

Overall, data suggest that primary anastomosis with proximal diversion may be safe in selective cases and reduces long-term stoma rates, but this must be balanced with patient factors.

LAPAROSCOPIC LAVAGE

9. LL is not routinely recommended. Colectomy is preferred for patients with a gross perforation or feculentperitonitis. Strength of recommendation: conditionalbased on moderate-quality evidence. The role of LL in treating patients with purulent peritonitis has been evaluated in 3 RCTs (LOLA, SCANDIV, and DILALA). [81],[82],[83]All the trials excluded patients with feculent peritonitis, and lavage is not appropriate for this group of patients. The LOLA trial was terminated early due to increased inhospital major morbidity and mortality in the lavage group compared to patients undergoing sigmoidectomy (37 vs 10 patient safety events, p = 0.005). [83] Despite these worse early outcomes, the primary end point (morbidity and mortality at 12 months) was comparable between the groups (resection: 60% vs laparoscopic lavage [LL]: 67%; p = 0.58). [62]In the SCANDIV trial, the rate of severe complications was comparable between the groups at 90 days and 1 year after surgery. [81],[82]In long-term follow-up (median, 59 months), the rates of severe complications (36% vs 35%; p = 0.92) and mortality (32% vs 25%; p = 0.36) were comparable between the 2 groups. However, unplanned reoperations were more frequent in the LL group (26% vs 12%; p = 0.03), which was primarily due to uncontrolled sepsis or abscess formation. Recurrence of diverticulitis was higher after LL ([21% vs 4%]; p = 0.004). [84]In the DILALA trial, 83 patients were randomly assigned to LL (n = 43) or Hartmann’s procedure (n = 40), with no difference in reoperations within 30 days between the 2 groups (13.2% vs 17.1%; p = 0.67). [79]Although reoperations after LL resulted in a 45% reduced risk of undergoing 1 or more reoperations within 24 months of surgery, the study included stoma reversal in the Hartmann group, which questions the primary outcome of this study. [63],[82]

Several meta-analyses and systematic reviews have attempted to clarify the contradictory results of studies regarding laparoscopic lavage, especially given that many patients who underwent LL for purulent peritonitis in these studies would typically be treated with antibiotics alone. [82],[83],[84],[85],[86]A review of 589 patients from the 3 RCTs and 4 comparative studies comparing resection to LL found that LL was more frequently used in younger patients with lower ASA class and was associated with significantly increased risks of intra-abdominal abscess, peritonitis, and future emergency reoperation. [85],[86]In this analysis, 36% of patients who underwent LL had a sigmoid colectomy within 1 year.

There is a paucity of level 1 evidence available regarding long-term outcomes of Hinchey III diverticulitis managed with LL, with no prospective comparisons to antibiotics alone. Available long-term outcomes after LL have been associated with a significantly decreased likelihood of having a stoma, tempered by the fact that there is an increased likelihood of postoperative abscess and recurrent diverticulitis. [78],[84]

EVALUATION AFTER RECOVERY FROM ACUTE DIVERTICULITIS

10. After resolution of acute diverticulitis, a colonoscopy should typically be performed in patients notcurrent with colorectal cancer screening guidelines or when radiologic findings are concerning for malignancy. Strength of recommendation: strong based onmoderate-quality evidence. Colorectal cancer can mimic diverticulitis. [87],[88]Given that the rate of colorectal cancer in patients with uncomplicated diverticulitis is the same as the general population, [89] patients with an episode of uncomplicated diverticulitis should undergo colonoscopy in accordance with current screening guidelines given the potential for colorectal neoplasms. [90]Multiple studies describe an increased risk of colorectal cancer in patients of advanced age and with complicated diverticulitis compared to those with uncomplicated diverticulitis. [91],[92]Meta-analyses describe colorectal cancer prevalence of 6% to 11% in patients with complicated disease compared to 0.7% to 1.3% in uncomplicated disease, [93],[94]with one study observing an RR of 5.03 (95% CI, 3.194–7.930; p < 0.001), [95]whereas another study reported 9.2 times increased odds of colorectal cancer for patients with complicated disease compared to uncomplicated. [96] Patients with CT findings associated with an increased likelihood of finding occult malignancy on endoscopy should typically undergo colonoscopy once the acute episode of diverticulitis has resolved. Although there are no specific radiographic findings of colorectal cancer in patients with diverticulitis, the presence of a colonic mass, obstruction, and mesenteric or retroperitoneal lymphadenopathy should typically raise suspicion. [97],[98]Although colonoscopy is generally recommended 6 to 8 weeks after resolution of acute diverticulitis, this interval is supported primarily by expert consensus and observational data demonstrating improved safety after resolution of inflammation.

If symptoms (eg, narrow stools, hematochezia, iron-deficiency anemia, unexplained weight loss) or clinical recovery are atypical, patients with uncomplicated diverticulitis should typically undergo further assessment with colonoscopy. [99]At present, there is insufficient evidence to support fecal immunochemical testing or multitarget stool DNA (Cologuard) testing as a replacement for colonoscopy after an episode of acute diverticulitis, and current recommendations continue to favor endoscopic evaluation when colonic assessment is indicated.

ELECTIVE SURGERY FOR ACUTE DIVERTICULITIS

11. The decision to recommend elective sigmoid colectomy after recovery from uncomplicated acute diverticulitis should be individualized. Considerationsinclude operative risk and potential gain in QoL, whilebalancing persistent abdominal symptoms, frequencyof recurrent episodes, and recurrence-related lifestylelimitations. Strength of recommendation: conditionalbased on moderate-quality evidence. Patients with uncomplicated diverticulitis treated nonoperatively experience recurrence rates of 13% to 33% and low rates of subsequent complicated disease or need for emergency operation. [22]Risk of recurrence is a function of the number of prior episodes. After a few episodes, patients are at a higher risk for recurrence. [2]After recovering from an initial episode of diverticulitis, the estimated risk of needing emergency surgery with stoma formation is 1 in 2000 patient-years of follow-up. [100]According to these data, 18 immunocompetent patients would need to undergo elective colectomy to prevent 1 emergency surgery for diverticulitis. [101]An observational study of 12,073 patients at their second treatment encounter for uncomplicated diverticulitis, of whom 19% underwent elective surgery and 81% were treated by medical therapy, demonstrated lower rates of recurrence (15% vs 61% at 5 years; adjusted HR 0.17 [95% CI, 0.15–0.20]) after surgery. [102] However, the ostomy rate after either treatment was low (surgery [inclusive of stoma related to the elective colectomy], 4.0%; medical therapy, 1.6%) and the risk of ostomy was not lower after elective resection.

An observational study from 1987 to 2012, including 84,313 patients hospitalized for diverticulitis, showed that the elective colectomy rate more than doubled without a significant decrease in the rate of emergency surgery or percutaneous drainage. [103]These data, together with the fact that most emergency resections are performed during index episodes of diverticulitis, support an individualized approach to the recommendation of elective colectomy for patients with uncomplicated diverticulitis. [101],[103],[104]

Patients who experience a recurrence of uncomplicated diverticulitis are at increasing risk of having further episodes. [105],[106]An observational study of 181,115 patients during a 25-year period who recovered from their first episode of diverticulitis nonoperatively found that 8.7% of patients went on to have a second admission for diverticulitis. [107]Interestingly, of those admitted 2 times, 23% required a third admission and, of the patients admitted 3 times, 36% ultimately required 4 or more hospitalizations. Another population-based study observed that 1-year recurrence rates increased from 8% after 1 episode to 19% after the second and up to 24% after the third. Conversely, with every year a patient remains recurrence-free, the risk of future recurrence decreases. [2]In a multicenter cohort study of 991 patients who experienced an index episode of acute uncomplicated diverticulitis and were managed without surgery, the 1-, 2-, and 3-year diverticulitis recurrence-free survival rates were 81.1%, 71.5%, and 67.5%, respectively. [108]However, with each additional year free of recurrence, the recurrence-free rates continue to improve each year: 88.2, 94.4, and 95%, respectively. The substantial heterogeneity in reported recurrence rates of diverticulitis in large epidemiological studies reflects variations in study design, duration of follow-up, diagnostic rigor (clinical vs CT-confirmed recurrence), capture of outpatient events, disease severity, and institutional practices regarding hospitalization, percutaneous drainage, and operative management.After repeated recurrences, patients may consider colectomy over observation. Consideration of elective colectomy after repeated episodes of uncomplicated diverticulitis should assess the operative risks unique to the patient, anastomotic leak and stoma formation, frequency and severity of prior flares (eg, work absenteeism, need for hospitalization), and persistent or residual symptoms related or attributed to prior episodes, as well as patient preferences. [109],[110],[111],[112]

The impact of elective colectomy on QoL has been analyzed in several trials. In a prospective study of 45 patients who underwent elective laparoscopic colectomy, 80% had significant improvement in their GI QoL index (GIQLI). [113]Another retrospective study of 105 patients noted improvements in QoL 12 months after surgery using a visual analogue scale. [114]The DIRECT trial, a multicenter, RCT of patients with recurrent diverticulitis or persistent abdominal complaints attributed to diverticular disease, compared 53 patients who underwent colectomy with 56 nonoperative patients in an intention-to-treat analysis. [115] One-third of these patients had persistent chronic abdominal symptoms. The primary end point, GIQLI at 6 months, was significantly better in the resection group (mean difference, 14.2; p < 0.001). The trial was terminated because of difficulties with recruitment and had particularly high rates of stoma formation (21%) and anastomotic leak (15%). At 5-year follow-up, the surgery group continued to have higher QoL in comparison with the nonoperative group (mean difference, 9.7; 95% CI, 1.7–17.7). The operative group also had improved short-form 36 physical (p = 0.03), mental (p = 0.01), and pain (p = 0.01) scores. [116]A cost-effectiveness study using the data from these groups of patients 1 year after treatment found a 0.06 difference in quality-adjusted life-years between the groups favoring resection, and this difference increased to 0.43 at 5 years. The authors concluded that elective sigmoid resection in patients with recurring diverticulitis was cost-effective. [117]

In the LASER trial, 90 patients were randomly assigned to observation or elective sigmoid resection after either 3 or more episodes of diverticulitis within a 2-year period, 1 or more episodes of conservatively treated complicated left colonic diverticulitis, or prolonged pain or disturbance in bowel habits for >3 months. [118]The mean difference in GIQLI score between randomization and 6 months was 12 points higher (a significant improvement in QoL) in the surgery group compared to the nonoperative treatment group, with a 10% major complication rate (Clavien-Dindo grade III or higher), including a 5% anastomotic leak rate, in the surgery group. There were 2 patients (5%) in the surgery group and 12 patients (31%) in the conservative treatment group who had new episodes of diverticulitis within 6 months. After a 2-year follow-up, this difference in GIQLI was preserved, and 61% of patients in the nonoperative group had recurrent diverticulitis compared with 11% in the surgery group. [119]Four years follow-up revealed high crossover rates from conservative treatment to surgery, indicating that patients with low QoL in the conservative treatment group often require surgical intervention. [120]In contrast to the 2 years follow-up, elective sigmoid resection did not improve QoL compared with conservative treatment in 4-year follow-up (GIQLI score 115.3 [17.8] in the surgery group vs 109.8 [19.8] in the conservative treatment group; mean difference, 5.54 [95% CI, −2.98 to 14.06]), although it was effective in preventing recurrences of diverticulitis (surgery 10% vs conservative 92%). Upfront surgery may be preferable in patients with low QoL, but initial conservative treatment is an option for patients with near-normal QoL.

Elective sigmoid resection is associated with improved QoL and reduced risk of recurrence for patients with either recurrent or persistent painful diverticulitis in these trials. [115],[118],[121]These benefits must be weighed against operative risks and morbidity, including anastomotic leak, infection, damage to adjacent structures, and longterm bowel dysfunction. Thus, the decision to proceed with surgery should be individualized through shared decision-making, considering the frequency of episodes, persistent symptoms, lifestyle constraints due to symptoms, and anxiety regarding the recurrence of diverticulitis without surgical intervention. The decision for elective colectomy should be based on a balance of the potential improvement in QoL gained by alleviating these factors, operative risk, and the potential for symptoms to persist or recur after colectomy.

12.Elective colectomy should typically be consideredafter successful nonoperative treatment of a diverticular abscess. Risk stratification should be individualizedaccording to symptoms, radiologic findings, operativerisks, and shared decision-making on prevention ofrecurrent diverticulitis. Strength of recommendation:conditional based on moderate-quality evidence. Patients treated nonoperatively after resolution of a diverticular abscess experience recurrences at a higher rate than patients who present with an initial episode of acute uncomplicated diverticulitis. Most of these recurrences can be managed nonoperatively, with few requiring emergency colectomy with an ostomy or resulting in death. [122],[123] However, elective sigmoid colectomy after a diverticular abscess typically results in relief from residual symptoms, prevents future diverticulitis attacks, and improves QoL. [114],[116],[117],[124]Recent literature makes a key distinction between treatment failure in the early period (30–90 days) and recurrence, which occurs during long-term follow-up after the index episode. [125],[126]Treatment failure represents ongoing disease that does not resolve with appropriate medical management with or without percutaneous drainage. This distinction highlights that patients with diverticular abscess are at increased risk of treatment failure after the index episode compared to those with uncomplicated diverticulitis. [126]A meta-analysis examining 42 studies, including 8766 patients who had a diverticular abscess successfully managed nonoperatively observed that 20% experienced treatment failure within 30 days of the index episode and 25% experienced a recurrent episode during long-term follow-up. [54]In older literature, treatment failure was not distinguished from recurrence, falsely elevating the reported recurrence rates. [123],[127]A retrospective review of the National Readmissions Database analyzed 201,384 patients hospitalized for diverticulitis, of whom 13.1% were admissions for complicated diverticulitis with abscess managed nonoperatively. [126]Treatment failure, defined as unplanned readmission for diverticulitis within 90days, was significantly higher among patients with an index episode of acute complicated diverticulitis compared with acute uncomplicated diverticulitis (12.5% vs 5.7%; p < 0.001). The median time to readmission for treatment failure was 21.0 days, and 85% of all readmissions occurred within 60 days of discharge. Complicated diverticulitis (OR 2.06; 95% CI, 1.97–2.16) was the most important factor associated with treatment failure. Close follow-up of patients with diverticular abscess initially managed nonoperatively is important to ensure that the abscess and colonic inflammation both resolve.

A randomized trial included patients with an index episode of acute diverticulitis complicated by abscess (15 patients) or by extra luminal air alone (92 patients). [124] Patients were randomly assigned to elective surgery or observation after successful nonoperative management in a 3:1 ratio. Rates of recurrent diverticulitis differed between the elective surgery and observation groups (8% vs 32%; p = 0.02); however, all recurrences in both groups were successfully managed nonoperatively. Using administrative data, a large study compared patients with an episode of complicated diverticulitis with abscess managed nonoperatively in 2 countries with contrasting health care systems. Interval elective sigmoid colectomy was undertaken in 3280 of 13,861 patients (24%) in Switzerland and in 231 of 5129 patients (5%) in Scotland. [122]Despite this 5-fold difference, the rate of emergency surgery or death in long-term follow-up (median >4 years) was 5% in both countries. Similar rates of recurrent diverticulitis were also observed (35.6% vs 36.8% in Switzerland and Scotland, respectively).

Once patients have fully recovered from a diverticular abscess, long-term recurrence rates are ~1 in 3, but the need for emergent surgery is low. [122],[128]A retrospective, multi-institution study analyzed the outcomes of 447 patients with an initial episode of diverticular abscess, most of whom (74.3%) were treated without percutaneous drainage. [56]After >30 days from the index episode, 37% experienced recurrent diverticulitis, of which 57% were uncomplicated, and 44% were complicated episodes. Only 13 patients (2.9%) required repeat percutaneous drainage,and 14 patients (3.1%) required emergent sigmoid resection. Abscess size and need for percutaneous drainage were not associated with recurrence.

Another study analyzed 10 342 patients who underwent nonoperative management of a diverticular abscess, of which 22% underwent percutaneous drainage. [128]Of this cohort, 3270 patients (32%) underwent colectomy within 30 days of diagnosis for treatment failure. Of the 7072 remaining patients, the 5-year recurrence rate for the 5412 patients who did not undergo elective surgery within 6 months was 25%. Only 7% had 2 or more episodes of recurrence and 14% had at least 1 recurrent episode of complicated diverticulitis. The rate of emergency colectomy was 8.1% within 5 years. Interestingly, 57% of recurrences occurred within the first year of initial admission for diverticular abscess, causing the 5-year diverticulitis recurrence rate to decrease to 13.2% and the emergency colectomy rate to 2.4% for the following years. The authors concluded that observation without elective colectomy after resolution of an initial diverticular abscess is a reasonable option. Somewhat contrary to this, Rose et al [105]showed a 16.3% recurrent diverticulitis rate after medical management of 210,268 patients with diverticulitis, with age more than 50 years (HR 5.19; 95% CI, 3.05–8.29), previous tobacco use (HR 1.40; 95% CI, 1.18–1.66), and abscess (HR 2.18; 95% CI, 1.60–2.97) as predictors of mortality on recurrence. The mortality of delayed elective colectomy after the first episode of emergent diverticulitis was 0.3% compared to 4.6% for emergent resection during the second episode.

Taken together, the evidence supports elective resection after successful nonoperative treatment of diverticulitis with abscess. Although elective colectomy should not be routinely considered for all patients, a risk stratification and shared decision-making process should be followed.

13. Elective colectomy is recommended for patientswith diverticulitis complicated by fistula or symptomatic stricture. Strength of recommendation: strongbased on low-quality evidence. In situations where diverticulitis is complicated by fistula formation, obstruction, or stricture, elective or semielective resection is recommended to provide symptomatic relief and improve QoL. [129]Although all types of symptomatic fistulas may be considered for elective colectomy, the most common fistula indications include colovesical, colovaginal, and colocutaneous. With the increasing quality of axial imaging, additional uncommon fistulas may be reported (eg, coloenteric, colocolonic, colouterine, and coloureteral). Elective colectomy should typically be discussed on an individualized basis according to symptoms and operative risk.

14. Elective colectomy for diverticular disease shouldnot typically be offered solely due to young age at disease onset. Strength of recommendation: strong basedon moderate-quality evidence. A meta-analysis of 27 studies, including 7477 patients with CT-confirmed diverticulitis, demonstrated a higher rate of diverticulitis recurrence (RR of 1.47; 95% CI, 1.20–1.80) for young patients (<40–50 years age group). [130]However, when limiting the analysis to studies that included survival analysis, taking length of follow-up per age group into account, no association between age and recurrent diverticulitis was found. In this meta-analysis, the proportion of complicated diverticulitis at presentation and the need for emergency surgery or percutaneous abscess drainage did not differ between young and older patients. These data indicate that young patients do not have a more severe course of acute diverticulitis and should not have a lower threshold for elective surgery merely based on age.

Young age has not been associated with an increased risk of more severe recurrences. A retrospective cohort study of 14,124 patients managed nonoperatively after an index attack of diverticulitis and followed for a median of 3.9 years (interquartile range, 1.7–6.4) demonstrated that younger patients had a slightly higher rate of readmission (10.5 vs 8.4%; p < 0.001) but similar risk of requiring emergency surgery compared with older patients (1.8 vs 2.0%; p = 0.52). [131]

15. The decision to offer elective colectomy after recoveryfrom uncomplicated or complicated acute diverticulitis,successfully managed nonoperatively, in immunosuppressed patients, should be individualized. Strengthof recommendation: conditional based on moderatequality evidence. Immunocompromised patients are a unique group that deserves consideration in terms of recommending elective colectomy after recovery from an acute episode of diverticulitis. Immunocompromised refers to a state in which an individual has a weakened or deficient immune system, resulting in reduced ability to mount an effective immune response to pathogens or malignancies. This condition may be congenital or acquired, and can result from underlying diseases (eg, HIV/AIDS, malignancy), medical treatments (eg, chemotherapy, immunosuppressive therapy, corticosteroids), solid or liquid organ transplantation, or other causes that impair immune cell function or production. Traditionally, it was thought that immunosuppressed patients experienced a more difficult course of diverticular disease, with more frequent and severe recurrences, leading to a lower threshold for elective colectomy after an index episode of diverticulitis. [122]However, recent literature suggests that immunosuppressed patients typically have recurrence rates and severity similar to those of immunocompetent patients. A large national study using data from 2014 to 2020 included 170,697 patients with evidence of acute diverticulitis, of whom 442 (0.2%) had a solid organ transplant. [132]Among patients who had not been censored at 1 year (n = 515), 112 (22%; 95% CI, 20%– 25%) experienced a recurrence within the first year. Solid organ transplantation was not significantly associated with the risk of recurrence (HR 1.19; 95% CI, 0.94–1.50), including complicated recurrence or hospitalization for recurrent diverticulitis. These data suggest that a universally low threshold for elective colectomy after successful medical treatment of acute diverticulitis in patients with solid organ transplantation is not typically warranted; rather, the decision to offer elective colectomy in patients with a solid organ transplant should follow the same principles as in a nontransplanted patient.

Most other studies assessing recurrence rates in immunosuppressed patients are single center, with small numbers and limited generalizability. A retrospective review of a single-institution experience across a 14-year interval compared 107 immunosuppressed patients with 550 immunocompetent patients who had successful medical management of their first episode of diverticulitis with a mean follow-up of 81.6 months. [133] The rate of recurrent diverticulitis was similar in both groups (21.5% of immunosuppressed patients vs 20.5% of immunocompetent patients; p = 0.82). Although immunosuppressed patients who had a severe first episode (defined as abscess or perforation) were significantly more likely to have a recurrence or a complicated recurrence, the rate of emergency surgery was comparable between groups.

Whether the specific underlying cause requiring immunosuppression (eg, steroid use, organ transplant, end-stage renal disease, connective tissue disease) should influence treatment recommendations is unclear, as most studies pool data across the spectrum of immunosuppression. One study, including 1181 patients admitted for acute diverticulitis at a single institution, of whom 192 were immunosuppressed, categorized patients into 5 types of immunosuppression: steroid, solid organ transplantation, chronic renal failure, and other causes. [134]They observed a 27.8% recurrence rate after successful nonoperative management with no differences between groups of immunosuppressed patients.

Immunosuppressed patients are at increased risk of complications after elective colectomy for recurrent diverticulitis. A retrospective review of the National Surgical Quality Improvement Program database compared 736 immunosuppressed patients with 21 980 immunocompetent patients who underwent elective colectomy for diverticulitis. [135]An adjusted analysis observed that the groups had comparable mortality, but the rates of major morbidity (OR 1.46; 95% CI, 1.17–1.83) and wound dehiscence (OR 2.69; 95% CI, 1.63–4.42) were significantly higher in the immunosuppressed group. A recent meta-analysis, including 2977 immunosuppressed patients and 780,630 immunocompetent patients in 11 studies, also reported greater morbidity after elective surgery in immunosuppressed patients compared to immunocompetent patients for elective surgery (RR 2.18; 95% CI, 1.02–4.65, p =

0.04). [44]The decision to proceed with elective colectomy for immunosuppressed patients should consider these increased risks.

TECHNICAL CONSIDERATIONS

16. Resection should include the entire segment of diseased colon and an anastomosis to the rectum. Strengthof recommendation: strong based on high-qualityevidence. In elective colectomy for diverticulitis, the extent of resection should not differ based on the surgical approach or the presence of complicated disease. Intraoperatively, the proximal margin, usually the descending colon, should be completely free of inflammation and fibrosis. The segment should be soft without induration or thickening. [136] Diverticula proximal to the sigmoid are common, but an extended resection to include these is not typically beneficial in the absence of inflammation or fibrosis.

The distal margin of transection should be the proximal rectum, as retained distal sigmoid with a colocolonic anastomosis is associated with a higher risk of recurrent diverticulitis. After colectomy, the 1-year risk of recurrent disease is ~5%. [102],[137],[138]However, patients with a colocolonic anastomosis have recurrence rates reported between 12% and 23%. [139],[140]

Mobilization of the splenic flexure is helpful when it allows a tension-free anastomosis, but it may be performed selectively based on colonic mobility and does not impact the risk of postoperative complications or disease recurrence. [141],[142],[143]Similarly, high ligation of the inferior mesenteric artery can be performed to increase length, but the level of arterial ligation is not associated with postoperative complications or functional outcomes. [144],[145]In general, these technical considerations also apply to emergency colectomy when an anastomosis is planned.

17. A minimally invasive approach to colectomy for diverticulitis is preferred when feasible andsafe. Strength of recommendation: strong based onmoderate-quality evidence. The 3 minimally invasive approaches to diverticulitis surgery are conventional laparoscopy, hand-assisted laparoscopy, and robotic surgery. All 3 approaches are safe, feasible, and associated with improved short-term outcomes compared to open surgery. [146],[147],[148]Hand-assisted surgery was used more frequently in the past as a bridge to laparoscopy and is now more commonly used for complicated diverticulitis with fistula. [149]Compared to laparoscopy, the robotic approach has been shown in some studies to be associated with a lower rate of conversion to open surgery. [150],[151],[152],[153],[154]Many of these studies included older robotic platforms and surgeons who were early on the learning curve. Retrospective comparisons of robotic and laparoscopic surgery are limited by significant selection bias andsurgeon preferences. Choice of approach is typically influenced by surgeon familiarity, equipment availability, and patient characteristics.

Minimally invasive surgery is safe in the setting of emergency sigmoid colectomy, and is also associated with improved short-term outcomes, including reduced surgical site infection. [155],[156],[157],[158]However, all studies on this topic are retrospective and should be interpreted with caution, as selection bias predominates.

ACKNOWLEDGMENTS

The authors express their appreciation to Rachel L. Walden, MLIS, of Vanderbilt University, Annette and Irwin Eskind Biomedical Library, for her help with the literature search and assistance with COVIDENCE, and to Anne Peery, MD, MSCR, for her close read and insightful comments.

References