ORIGINAL CONTRIBUTION
Medically Treated Diverticular Abscess Associated With High Risk of Recurrence and Disease Complications Bikash Devaraj, M.D. • Wendy Liu, M.D. • James Tatum, M.D. • Kyle Cologne, M.D. Andreas M. Kaiser, M.D. Division of Colorectal Surgery, Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California
BACKGROUND: The best management for diverticulitis with abscess formation remains unknown.
the whole cohort and the subgroup of patients with percutaneous drainage for diverticular abscess.
OBJECTIVE: The purpose of this study was to determine the natural course and outcomes of patients with medically treated diverticular abscess.
RESULTS: During the initial presentation, 25 patients failed nonoperative management and required an urgent operation. A total of 185 patients were initially successfully managed without surgery and were discharged from the hospital. Of these, recurrent diverticulitis developed in 112 (60.5%) after an average time interval of 5.3 months (range, 0.8–20.0 months); 47 patients (42%) experienced more than 1 episode. The modified Hinchey stage at time of recurrence (compared with index stay) increased in 51 patients (45.6%). Seventy one (63%) of 112 recurrences showed local disease complications (recurrent abscess, fistula, stricture, or peritonitis). Fistula formation (colovesicular/colovaginal/ colocutaneous) and recurrent abscess were the 2 most frequent complications. Twenty nine (26%) of 112 recurrences required an urgent operation; overall, 66 (59%) of 112 patients eventually underwent surgery at our institution. The original abscess size in patients who later developed recurrences was significantly larger than in patients who did not develop recurrence (5.3 vs 3.2 cm; p < 0.001). Paradoxically, larger abscesses also had a higher chance of successful CT-guided drainage (average size, 6.5 cm; range, 1.1–14 cm), yet CT-guided drainage did not change the overall outcome. Of 65 (31.0%) of 210 patients with CT-guided drainage, 45 (73.8%) of 61 after initial success experienced a recurrence. Furthermore, local disease complications at the time of recurrence were noted in 32 of 61 patients (52.5% of all CT-guided drainage, 71.1% of postCT–guided drainage recurrences), and 13 (29.2%) of 45 patients with recurrence after successful CT-guided drainage subsequently required an urgent operation.
DESIGN: We conducted a retrospective review of all patients at our institution with diverticular abscess confirmed by CT from 2004 to 2014. SETTINGS: This study was conducted in a tertiary referral
hospital. PATIENTS: A total of 1194 patients were treated for acute diverticulitis in 10 years; 210 patients with CTdocumented diverticular abscess were analyzed (140 men (66.7%) and 70 women (33.3%); median age 45 years; range, 23–84 years). MAIN OUTCOME MEASURES: Overall recurrence and disease complication rates, as well as the need for subsequent operation after initial successful nonsurgical management, were measured, along with analysis of Supplemental digital content is available for this article. Direct URL citations appear in the printed text, and links to the digital files are provided in the HTML and PDF versions of this article on the journal’s Web site (www.dcrjournal.com). Financial Disclosure: None reported. Podium presentation at the meeting of The American Society of Colon and Rectal Surgeons, Boston, MA, May 30 to June 3, 2015. Correspondence: Andreas M. Kaiser, M.D., Department of Colorectal Surgery, Keck School of Medicine, University of Southern California, 1441 Eastlake Ave, Suite 7418, Los Angeles, CA 90033. E-mail: akaiser@ usc.edu Dis Colon Rectum 2016; 59: 208–215 DOI: 10.1097/DCR.0000000000000533 © The ASCRS 2015
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LIMITATIONS: The study was limited by its retrospective noncomparative design. Diseases of the Colon & Rectum Volume 59: 3 (2016)
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CONCLUSIONS: Diverticular abscesses represent complicated diverticulitis and are associated with a high risk of recurrences and disease complications. Recurrences (contrary to other series) were often more severe than the index presentation. The successful CTguided drainage of a diverticular abscess does not appear to lower the risks of future recurrence or complication rates and frequently is only a bridge to surgery. After initial successful nonoperative management, patients with diverticular abscess should be offered interval elective colectomy (see Video, Supplemental Digital Content 1, http://links.lww.com/DCR/A216).
KEY WORDS: Diverticular abscess; Recurrence rates; Complications; Fistula; Stricture; Percutaneous drainage; Complicated diverticulitis; Modified Hinchey grade IB and II; Management; Surgery; Resection; Colectomy; Observation.
D
iverticulitis with abscess formation, that is, complicated diverticulitis of intermediate severity, remains a remarkably uncharted territory with regard to its best management. In contrast, there is broad consensus that medical therapy is the default choice for uncomplicated diverticulitis, as is immediate surgery for the most severe emergency presentations of acute diverticulitis (macroperforation, diffuse peritonitis, or obstruction).1 The increasingly recognized group in between of ≈25% of the patients on cross-sectional imaging show evidence of complicated diverticulitis with abscess formation.2–4 Current strategies start with antibiotics and possible CT-guided drainage (CGD) but if unsuccessful proceed to surgery during the same admission. Those with resolution of symptoms (signs of sepsis and of the abscess itself), however, are managed very differently from institution to institution, with some being recommended an elective operation.5 Until a decade ago, an elective sigmoid resection was recommended after 2 episodes of uncomplicated diverticulitis and after even a single attack of complicated but nonemergency diverticulitis in an attempt to prevent more severe disease in the event of a recurrence.6–8 This strategy has since been called into question by decision–analysis models, as well as by a number of reports suggesting that the first episode of diverticulitis is typically the most severe one and that patients with a history of more than 2 previous episodes of diverticulitis were at no greater risk of surgical morbidity or mortality at the time of a complicated recurrence than were patients with 1 to 2 episodes before the eventual surgery.9–11 Nonetheless, the most recent practice parameters of the American Society of Colon and Rectal Surgeons for the management of diverticulitis maintained that, in light of the high recurrence rates after initial nonoperative management of
complicated diverticulitis with abscess formation, an elective colectomy should be considered, particularly in those with a mesocolic or pelvic abscess of ≥5 cm.6–8 In 2014, we published a systematic review on the role of elective resection versus observation after nonoperative management of complicated diverticulitis with abscess formation and noted that identification of an abscess was associated with a high probability of resective surgery, whereas medical management frequently resulted in chronic or recurrent diverticular symptoms.12 However, it is generally acknowledged that the natural history of complicated diverticulitis beyond the index hospital stay has not been well analyzed. Contributing to the limitations in the literature are the lack of systematic and long enough follow-up in general, combined with the fact that patient cohorts to be followed are reduced to the individuals with more benign disease, whereas the worst cases are addressed with surgery and, hence, eliminated.11,13–15 As for the goal to prevent severe recurrent disease, as well as the likelihood of a stoma, the skewed data leave the surgeons without clear guidance about patient selection for and appropriate timing of elective resections. In the current communication, we attempted to address some of these issues by reviewing all of the cases of complicated diverticulitis at our institution within a 10-year period as defined by CT evidence of an abscess. The objectives of our analysis were as follows: 1) to define the impact of an abscess as evidence of complicated diverticulitis on the risk of failure of medical treatment, 2) to define the incidence and severity of recurrent attacks with a need for resective surgery, and 3) to determine the impact of CGD of the abscess. Our association with a major county hospital serving an indigent patient population with little ability to seek care outside of our facility offers an unparalleled opportunity to examine this question because of the lack of resources necessary to routinely offer elective sigmoid resection. We hypothesized that the rate of recurrent severe diverticulitis (defined as requiring more than just antibiotics) after seemingly resolved complicated diverticulitis with abscess is much higher than previously estimated in the literature.
PATIENTS AND METHODS Patient Population
Patients who were treated for acute diverticulitis between 2004 and 2014 at the Los Angeles County/University of Southern California Medical Center were identified and screened, and the disease was classified according to the modified Hinchey classification (Table 1).3,16 Included in our analysis and retrospectively analyzed were patients who, on CT, were reported to have evidence of diverticular abscess(es). Excluded were patients who were admitted primarily for stoma reversal after diverticular surgery;
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TABLE 1. Hinchey classification and modified Hinchey classification of acute diverticulitis3,16 Hinchey classification
Modified Hinchey classification 0
I
Pericolic abscess or phlegmon
II
Pelvic, intra-abdominal, or retroperitoneal abscess Generalized purulent peritonitis Generalized fecal peritonitis
III IV
IA IB II III IV FIST OBST
Mild clinical diverticulitis LLQ pain, fever No confirmation by elevated WBC, imaging, or surgery Confined pericolic inflammation, phlegmon Confined pericolic abscess Pelvic, distant intra-abdominal, or retroperitoneal abscess Generalized purulent peritonitis: no open communication with bowel lumen Fecal peritonitis: free perforation, open communication with bowel lumen Colovesical/colovaginal/coloenteric/colocutaneous fistula formation Stricture with large and/or small bowel obstruction
FIST = fistula formation; OBST = obstruction; LLQ = lower left quadrant; WBC = white blood cell.
atients who, in the hospital course, were found to have a p colon cancer that mimicked acute diverticulitis; or patients with relevant data deficiencies. The full electronic medical charts and CT images were reviewed and the following data entered into a datasheet generated with Microsoft Excel 2010: patient demographics, symptoms and duration of symptoms, past history of diverticulitis, comorbidities, previous abdominal surgery, clinical signs, white blood cell counts, abscess size, recurrence, and disease complications. Primary outcome measures were overall recurrence and disease complication rates, as well as the need for a subsequent operation after initial successful nonsurgical management. Evaluation was carried out for the whole cohort, as well as for the subgroup of patients with percutaneous drainage for diverticular abscess. The study protocol and data collection were approved by the institutional review board of the University of Southern California and were consistent with Health Insurance Portability and Accountability Act of 1996 regulations.
patients developed purulent or feculent peritonitis during the index hospitalization and were therefore reclassified as modified Hinchey III and IV. The patient characteristics at the time of the index admission are shown in Table 2. The overall average abscess size was 4.0 ± 2.4 cm (median, 3.7 cm; range, 0.5–14.0 cm). There was no mortality recorded in the cohort. Total length of stay was 7.0 ± 9.7 days (median, 4.0 days; range, 1.0–85.0 days). Average followup was 13.6 ± 9.3 months (median, 12.0 months; range, 3.0–70.0 months). Index Hospitalization
Of all 210 patients with diverticular abscesses at the time of the index admission, 25 patients (11.9%) required an urgent operation. This nonelective setting was associated with 80% of the surgeries being performed with the Hartmann procedure with creation of an end colostomy and a substantially longer length of hospital stay (24.3 ± 27.1 days; median, 13.0 days; range, 5.0–85.0 days). CGD was
Statistical Analysis
TABLE 2. Characteristics of 210 patients with diverticular abscess
Results were reported in descriptive statistics using SigmaPlot 13.0 software (Systat Software Inc, San Jose, CA) and expressed as mean ± SD or median with range. Statistical analysis was performed to compare groups or parameters using the χ2 test or the Fisher exact test for nominal variables and the Mann-Whitney rank-sum test or Student t test for continuous variables. Observed differences were considered statistically significant if p < 0.05.
RESULTS
Index hospital stay
Median age, y Sex, women/men Previous episodes of diverticulitis, n (%) ASA classification, n (%) Class I Class II Class III Unclassified Length of stay, mean ± SD, d
45 (range 18–87) 140/70 29 (14%)
Abscess size, mean ± SD, cm
Patient Characteristics
During the study period, 1194 patients presented with acute diverticulitis to Los Angeles County/University of Southern California Medical Center, a large metropolitan county hospital. On the basis of the modified Hinchey classification (Table 1), 210 patients met the inclusion criteria because they had CT evidence for a diverticular abscess. The majority of patients had a pericolonic (stage IB, 48%) or a pelvic abscess (stage II, 42%); in addition, 17 and 5
Characteristic
CT drain placement, n (%) Success, n/N (%) Failure, n (%) Modified Hinchey classification, n (%)a IB II III IV
50 (24) 111 (53) 32 (15) 17 (8) 7.0 ± 9.7 (median, 4.0; range, 1.0–85.0) 4.0 ± 2.4 (median 3.7, range 0.5 – 14.0) 65 (31) 61/65 (93.8) 4 (6.2) 100 (48) 88 (42) 17 (8) 5 (2)
Modified Hinchey classification as previously published.3,16
a
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All cases of acute diverticulitis (n = 1194) CT documented abscess (n = 210) Nonoperative management (n = 185)
Urgent operation (n = 25)
Recurrent diverticulitis (n = 112) Urgent operation (n = 29)
No documented recurrence (n = 73)
Subsequent operation (n = 37)
Operation attributed to ideology (n = 1)
Chronic complication (obstruction, fistula, smoldering) (n = 31)
Ideology (n = 6)
FIGURE 1. Flow chart of management of the entire cohort of patients with acute diverticulitis.
performed in 65 (31%) of 210 patients. The abscess size in the group with CGD was 6.5 ± 2.8 cm (median, 6.0 cm; range, 1.1–14.0 cm), significantly larger than 3.4 ± 1.7 cm (median, 3.0 cm; range, 0.5–10.2 cm) in the group who were managed without CGD (p < 0.05). A total of 93.8% of CGDs were successful and resulted in resolution of the acute symptomatology (white blood cell count, fever, pain, and tachycardia); it failed to resolve the diverticulitis attack in 4 patients who subsequently required an urgent operation. In contrast, 185 of 210 patients with abscesses were successfully managed medically using antibiotics with/without CGD (Fig. 1) and eventually were discharged from the hospital after a significantly shorter length of stay of 5.1 ± 4.6 days (median, 4.0 days; range, 1.0–28.0 days; p < 0.05).
(colovesicular/colovaginal/colocutaneous) and recurrent abscesses were the 2 most frequent complications affecting 39.4% and 45.1% of the patients. The majority of the 29 fistulas in 28 patients were to the bladder (n = 15), followed by fistulas to the vagina (n = 5) and enterocutaneous fistulas (n = 5), which were typically related to the CGD tract; the rest were internal fistulas. Fifty one of the patients (45.6%) had a more severe episode at recurrence, reflected by an increased modified Hinchey class when compared with the original stage at the time of the index hospitalization. TABLE 3. Characteristics of recurrences of diverticulitis (N = 112 patients)
Recurrent Diverticulitis
Of the 185 patients who were successfully treated nonoperatively during the index hospital stay and discharge from the hospital, 112 (61%) subsequently developed recurrent diverticulitis after an average of 5.4 ± 6.1 months (median, 3.5 months; range, 0.8–36.0 months); 47 (42%) of 112 individuals experienced more than 1 episode (Table 3). At the time of the recurrence, 63% of the patients showed complicated diverticulitis (Fig. 2), whereby fistula formation
Characteristic
At time of recurrence
Time to recurrence, mean ± SD, mo
5.4 ± 6.1 (median, 3.5; range, 0.8–36.0) 13.6 ± 9.3 (median, 12.0; range, 3.0–70.0) 47 (42) 51 (45.6)
Follow-up, mean ± SD, mo Multiple recurrences, n (%) Increase in modified Hinchey class, n (%) Characterization of recurrence, n (%) Complicateda Uncomplicatedb
71 (63.4) 41 (36.6)
Complicated indicates recurrent abscess, fistula, obstruction, peritonitis (modified Hinchey IB or higher). Uncomplicated indicates modified Hinchey class IA.
a
b
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Devaraj et al: Recurrence After Diverticular Abscess
IB (n = 8)
II (n = 21)
III (n = 8)
Recurrent diverticulitis (n = 112)
Complicated (n = 71) 63.4%
IV (n = 1)
Fistula (n = 25) Uncomplicated (modified Hinchey IA) (n = 41) 36.6%
Obstruction (n = 4)
IB + fistula (n = 1)
Combination (n = 4)
II + fistula (n = 2)
IB + obstruction (n = 1)
FIGURE 2. Flow chart of operative management.
The original abscess size in patients who later developed recurrences was significantly larger than in the patients who did not develop recurrence (5.3 ± 2.8 vs 3.2 ± 1.4 cm; p < 0.001). Twenty nine (26%) of 112 patients with recurrences required an urgent operative intervention because of the acuity of presentations. An additional 37 patients eventually underwent an elective colectomy whereby the indication in 31 patients (28%) was based on complications of the recurrence with stricturing and large bowel obstruction, fistula formation, smoldering symptoms, or combinations thereof (Fig. 2). Only the remaining 6 patients had a resection performed based on ideology, that is, the recommendation to perform an elective surgery to prevent future attacks (Figs. 1 and 3). Overall Risk to Require Surgery
Complicated diverticulitis as characterized by CT presence of an abscess was associated with a 25.7% risk (54 of 210 patients) of needing an urgent operation, either during the index admission or a subsequent recurrent attack (Fig. 3). In the urgent surgery setting (59% of all surgeries), Hartmann procedure with stoma dominated primary anastomosis, with 56% and 44%. Within the follow-up period, a total of 92 (44.0%) of the 210 patients eventually underwent an operation at our institution, with an overall 36.9% probability
of a stoma; it is unknown although whether and how many additional patients had surgeries carried at other institutions. The indication for the overwhelming majority of performed operations (92% (85 of 92)) was based on the severe and nonresolving acute or chronic nature of the disease as stated above; in contrast, only 7 patients (8%) underwent a surgery based on their history rather than active symptomatology (ideology indication). A total of 97.3% of all elective operations were carried out with a primary anastomosis. Impact of CGD
Although CGD of diverticular abscesses, as stated previously, had a high initial success rate of 93.8% (61 of 65 patients) during the index admission (Fig. 4), a substantial proportion of 45 (74.0%) of 61 patients developed a recurrence. Of these 45 patients, 71% presented again with complicated diverticulitis with abscess, fistula, obstruction, or peritonitis. Five (8.2%) of the 61 patients developed a colocutaneous fistula along the drain track. Twenty five (55.6%) of the 45 patients with recurrence after CGD required a surgical intervention.
DISCUSSION The natural history of patients with complicated diverticulitis and diverticular abscess formation is still poorly
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All patients with abscess (n = 210)
Total surgery (n = 92)
Ideology (n = 6+1)
Chronic complications (n = 31)
Urgent presentation (n = 54)
FIGURE 3. Flow chart of characteristics of recurrent diverticulitis.
understood, both during the index hospital stay and even more after successful initial nonoperative management.12 The necessity of an elective resection versus continued observation after an episode of complicated diverticulitis is under debate.12,17,18 Arguments against elective surgery after an acute episode of nonspecified diverticulitis have been made in different ways (based on the disease behavior and the morbidity of a surgery as such). Decision analysis models, as well as a number of retrospective studies, suggested that the risk of subsequent more severe attacks was low and did not warrant an elective resection9,11,13; however, several limitations had not been sufficiently considered, most notably the uncertain follow-up in patient populations with a nonmalignant disease on one hand and the fact that, often, surgical intervention had eliminated the patients with the worst disease from Total CGD (n = 65)
Immediate failure requiring urgent opera on (n = 4 (6%))
Ini al success (n = 61 (94%))
Recurrence (n = 45 (74%))
No recurrence (n = 16 (26%))
Complicated (n = 32 (71%))
Uncomplicated (n = 13 (29%))
FIGURE 4. Outcomes of CT-guided drainage (CGD).
the cohorts and, hence, artificially lowered the true recurrence risk.14,15 With more specific focus on patients with complicated diverticulitis, some authors argued that even those patients can and should be managed medically.19–22 These mostly retrospective studies were generally limited by small sample size and varying treatment philosophies, such that definitive conclusions were difficult to ascertain.12 Gaertner et al19 analyzed a subgroup of 32 patients with severe medical comorbidities who underwent percutaneous drainage but were deemed too high risk for a subsequent colectomy. They reported a recurrence-free survival of 58% at 7.4 years.19 The characteristics of this very small study population preclude widespread extrapolation of its results. In addition, when all of the patients from the original study group (n = 218) were analyzed, the colectomy-free survival was only 17%, hence making it difficult to use that study in support of a nonoperative strategy. Our recently published systematic review of 22 studies with a total of 1051 patients with diverticular abscess found that only 28% of patients did not undergo surgery or have a recurrence during follow-up and that recurrence rates were 39% even in patients awaiting elective resection.12 The 2014 American Society of Colon and Rectal Surgeons practice parameters for the treatment of sigmoid diverticulitis strongly recommend elective colectomy after an episode of complicated diverticulitis.6 In our current study, we attempted to find answers to some of these important issues by retrospective review of a comparably large patient cohort with CT evidence of an abscess. As stated in the introduction, the limitations of institutional resources on one hand and of patient access to other healthcare facilities on the other hand allowed for a rare study of the natural course of the disease. Because of significant resource limitations, routine or expeditious elective colectomy on patients after an episode of complicated diverticulitis is difficult to implement. Furthermore, the indigent patient population has little ability to seek care outside of our facility except in emergencies. We therefore have reason to believe that the presented numbers of recurrences and necessary surgeries are representative of the disease and, if at all, underestimate rather than overestimate those events. From the preceding 10 years from 1994 to 2004, we previously reported a recurrence rate of 42% in patients with medically managed diverticular abscess.3 Our current study, with 210 patients and, hence, more than double the original study population, showed an even higher documented recurrence rate of ≥61%; a total of 44% underwent a colectomy at our institution, whereby 54% of patients who developed recurrent disease after initial medical management were unable to avoid an operative intervention, and 26% required even an urgent operation. This number represents a minimum and could even be higher with longer follow-up; if our assumption that patients would,
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by necessity, come back to our institution was incorrect and/or they were seeking emergency care elsewhere; or if some were lost to follow-up. Furthermore, contrary to the reported belief that recurrent episodes tend to be milder than the first attack,10,22–25 we found that 63% of the recurrent episodes were complicated by abscess, peritonitis, fistula, and/or obstruction. In fact, 45.6% of the recurrences were more severe than at the time of the index presentation, as evidenced by an upstage from the original modified Hinchey class. Thus, for a significant proportion of these patients, watchful waiting proved to be detrimental and was associated with a substantially higher colostomy rate (56%) than if an elective resection had been contemplated and performed (3%). In addition, these complications can lead to recurrent hospitalizations, decreased quality of life, lost wages, and increased healthcare costs. With the advent of CT-guided percutaneous drainage, some authors advocate a nonoperative approach to patients who were successfully treated during the index admission.18,19,21,26–31 Although CGD is highly successful at avoiding the need for emergent operation, it does not appear to reliably prevent overall recurrences or additional disease complications. Paradoxically, larger abscesses were more likely drainable by CGD on one hand, but the larger abscess size might suggest a more advanced disease process on the other hand. This would explain that a nonnegligible number of individuals in our study developed a colocutaneous fistula along the drain track (an observation not reported previously in other studies); only 26% of the patients remained disease-free after the initial CGD. Therefore, patients with even successful percutaneous drainage of a diverticular abscess should be cautioned that it might not be a definitive management but rather a bridge to interval elective colectomy. Our study represents one of the largest series to date looking at the long-term outcome of patients who were medically managed after complicated diverticulitis. The limitations of our study are its retrospective nature and relatively short follow-up, the latter of which in fact would emphasize the high recurrence risk. The median time to recurrence in our study is only 3.5 months (range, 0.8–36.0 months), which suggests that at least some proportion of patients had smoldering disease despite having resolved the acute episode and meeting discharge criteria on index admission. Given the retrospective nature of the study, however, it is difficult to decipher the exact percentage of such patients, and the reasons are subject to speculation (disease, patient, and compliance related). Nevertheless, we feel that both smoldering and recurrent disease highlight the complexity of diverticular abscesses. Hence, our findings not only illustrate the high incidence of recurrent attacks but also of complications associated with those recurrences. These complications increase morbidity and the probability of a stoma, all of which could potentially be prevented with timely elective interval colectomy.
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CONCLUSION Diverticular abscesses represent complicated diverticulitis and are associated with a higher than previously reported risk of recurrences and disease complications. Recurrences (contrary to other series) were often more severe than the index presentation. Successful CGD of diverticular abscess does not appear to lower the risks of future recurrence or complication rates and may only be a bridge to surgery. After initial successful nonoperative management, patients with diverticular abscess should be offered interval elective colectomy. ACKNOWLEDGMENT We are indebted to Michael Ruiz for his constructive support in preparing this article and the computer skills to generate presentable tables and graphs. REFERENCES 1. Kaiser AM. McGraw-Hill Manual: Colorectal Surgery. http://accesssurgery.com/resourceToc.aspx?resourceID=211; Accessed April 12, 2015. 2. Ambrosetti P, Robert J, Witzig JA, et al. Incidence, outcome, and proposed management of isolated abscesses complicating acute left-sided colonic diverticulitis: a prospective study of 140 patients. Dis Colon Rectum. 1992;35:1072–1076. 3. Kaiser AM, Jiang JK, Lake JP, et al. The management of complicated diverticulitis and the role of computed tomography. Am J Gastroenterol. 2005;100:910–917. 4. Schoetz DJ Jr. Diverticular disease of the colon: a century-old problem. Dis Colon Rectum. 1999;42:703–709. 5. Alvarez JA, Baldonedo RF, Bear IG, et al. Presentation, management and outcome of acute sigmoid diverticulitis requiring hospitalization. Dig Surg. 2007;24:471–476. 6. Feingold D, Steele SR, Lee S, et al. Practice parameters for the treatment of sigmoid diverticulitis. Dis Colon Rectum. 2014;57:284–294. 7. Rafferty J, Shellito P, Hyman NH, et al. Practice parameters for sigmoid diverticulitis. Dis Colon Rectum. 2006;49:939–944. 8. Wong WD, Wexner SD, Lowry A, et al. Practice parameters for the treatment of sigmoid diverticulitis–supporting documentation: the Standards Task Force–the American Society of Colon and Rectal Surgeons. Dis Colon Rectum. 2000;43:290–297. 9. Salem L, Veenstra DL, Sullivan SD, et al. The timing of elective colectomy in diverticulitis: a decision analysis. J Am Coll Surg. 2004;199:904–912. 10. Chapman JR, Dozois EJ, Wolff BG, et al. Diverticulitis: a progressive disease? Do multiple recurrences predict less favorable outcomes? Ann Surg. 2006;243:876–883. 11. Chapman J, Davies M, Wolff B, et al. Complicated diverticulitis: is it time to rethink the rules? Ann Surg. 2005;242:576–581. 12. Lamb MN, Kaiser AM. Elective resection versus observation after nonoperative management of complicated diverticulitis with abscess: a systematic review and meta-analysis. Dis Colon Rectum. 2014;57:1430–1440.
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13. Guzzo J, Hyman N. Diverticulitis in young patients: is resection after a single attack always warranted? Dis Colon Rectum. 2004;47:1187–1190. 14. Kaiser AM. Diverticulitis in young patients: why we still should not pretend to know. Dis Colon Rectum. 2005;48:172. 15. Kaiser AM. Complicated diverticulitis: it is not yet time to rethink the rules! Ann Surg. 2006;243:707–708. 16. Wasvary H, Turfah F, Kadro O, et al. Same hospitalization resection for acute diverticulitis. American Surgeon. 1999;65:632–636. 17. Chautems RC, Ambrosetti P, Ludwig A, et al. Long-term followup after first acute episode of sigmoid diverticulitis: is surgery mandatory? A prospective study of 118 patients. Dis Colon Rectum. 2002;45:962–966. 18. Ambrosetti P, Chautems R, Soravia C, et al. Long-term outcome of mesocolic and pelvic diverticular abscesses of the left colon: a prospective study of 73 cases. Dis Colon Rectum. 2005;48:787–791. 19. Gaertner WB, Willis DJ, Madoff RD, et al. Percutaneous drainage of colonic diverticular abscess: is colon resection necessary? Dis Colon Rectum. 2013;56:622–626. 20. Bridoux V, Antor M, Schwarz L, et al. Elective operation after acute complicated diverticulitis: is it still mandatory? World J Gastroenterol. 2014;20:8166–8172. 21. Elagili F, Stocchi L, Ozuner G, et al. Outcomes of percutaneous drainage without surgery for patients with diverticular abscess. Dis Colon Rectum. 2014;57:331–336. 22. Suarez Alecha J, Amoza Pais S, Batlle Marin X, et al. Safety of nonoperative management after acute diverticulitis. Ann Coloproctol. 2014;30:216–221.
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23. van de Wall BJ, Draaisma WA, Consten EC, et al. Does the presence of abscesses in diverticular disease prelude surgery? J Gastrointest Surg. 2013;17:540–547. 24. Nelson RS, Ewing BM, Wengert TJ, et al. Clinical outcomes of complicated diverticulitis managed nonoperatively. Am J Surg. 2008;196:969–974. 25. Ritz JP, Lehmann KS, Frericks B, et al. Outcome of patients with acute sigmoid diverticulitis: multivariate analysis of risk factors for free perforation. Surgery. 2011;149:606–613. 26. Felder SI, Barmparas G, Lynn J, et al. Can the need for colectomy after computed tomography-guided percutaneous drainage for diverticular abscess be predicted? Am Surg. 2013;79:1013–1016. 27. Hall J. Should elective colectomy be routine following percutaneous drainage of a diverticular abscess? Dis Colon Rectum. 2013;56:533–534. 28. Singh B, May K, Coltart I, et al. The long-term results of percutaneous drainage of diverticular abscess. Ann R Coll Surg Engl. 2008;90:297–301. 29. Brandt D, Gervaz P, Durmishi Y, et al. Percutaneous CT scan-guided drainage vs. antibiotherapy alone for Hinchey II diverticulitis: a case-control study. Dis Colon Rectum. 2006;49:1533–1538. 30. Durmishi Y, Gervaz P, Brandt D, et al. Results from percutaneous drainage of Hinchey stage II diverticulitis guided by computed tomography scan. Surg Endosc. 2006;20:1129–1133. 31. Siewert B, Tye G, Kruskal J, et al. Impact of CT-guided drainage in the treatment of diverticular abscesses: size matters. AJR Am J Roentgenol. 2006;186:680–686.
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Medically Treated Diverticular Abscess Associated With High Risk of Recurrence and Disease Complications Bikash Devaraj, M.D. • Wendy Liu, M.D. • James Tatum, M.D. • Kyle Cologne, M.D. Andreas M. Kaiser, M.D. Division of Colorectal Surgery, Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California
BACKGROUND: The best management for diverticulitis with abscess formation remains unknown.
the whole cohort and the subgroup of patients with percutaneous drainage for diverticular abscess.
OBJECTIVE: The purpose of this study was to determine the natural course and outcomes of patients with medically treated diverticular abscess.
RESULTS: During the initial presentation, 25 patients failed nonoperative management and required an urgent operation. A total of 185 patients were initially successfully managed without surgery and were discharged from the hospital. Of these, recurrent diverticulitis developed in 112 (60.5%) after an average time interval of 5.3 months (range, 0.8–20.0 months); 47 patients (42%) experienced more than 1 episode. The modified Hinchey stage at time of recurrence (compared with index stay) increased in 51 patients (45.6%). Seventy one (63%) of 112 recurrences showed local disease complications (recurrent abscess, fistula, stricture, or peritonitis). Fistula formation (colovesicular/colovaginal/ colocutaneous) and recurrent abscess were the 2 most frequent complications. Twenty nine (26%) of 112 recurrences required an urgent operation; overall, 66 (59%) of 112 patients eventually underwent surgery at our institution. The original abscess size in patients who later developed recurrences was significantly larger than in patients who did not develop recurrence (5.3 vs 3.2 cm; p < 0.001). Paradoxically, larger abscesses also had a higher chance of successful CT-guided drainage (average size, 6.5 cm; range, 1.1–14 cm), yet CT-guided drainage did not change the overall outcome. Of 65 (31.0%) of 210 patients with CT-guided drainage, 45 (73.8%) of 61 after initial success experienced a recurrence. Furthermore, local disease complications at the time of recurrence were noted in 32 of 61 patients (52.5% of all CT-guided drainage, 71.1% of postCT–guided drainage recurrences), and 13 (29.2%) of 45 patients with recurrence after successful CT-guided drainage subsequently required an urgent operation.
DESIGN: We conducted a retrospective review of all patients at our institution with diverticular abscess confirmed by CT from 2004 to 2014. SETTINGS: This study was conducted in a tertiary referral
hospital. PATIENTS: A total of 1194 patients were treated for acute diverticulitis in 10 years; 210 patients with CTdocumented diverticular abscess were analyzed (140 men (66.7%) and 70 women (33.3%); median age 45 years; range, 23–84 years). MAIN OUTCOME MEASURES: Overall recurrence and disease complication rates, as well as the need for subsequent operation after initial successful nonsurgical management, were measured, along with analysis of Supplemental digital content is available for this article. Direct URL citations appear in the printed text, and links to the digital files are provided in the HTML and PDF versions of this article on the journal’s Web site (www.dcrjournal.com). Financial Disclosure: None reported. Podium presentation at the meeting of The American Society of Colon and Rectal Surgeons, Boston, MA, May 30 to June 3, 2015. Correspondence: Andreas M. Kaiser, M.D., Department of Colorectal Surgery, Keck School of Medicine, University of Southern California, 1441 Eastlake Ave, Suite 7418, Los Angeles, CA 90033. E-mail: akaiser@ usc.edu Dis Colon Rectum 2016; 59: 208–215 DOI: 10.1097/DCR.0000000000000533 © The ASCRS 2015
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LIMITATIONS: The study was limited by its retrospective noncomparative design. Diseases of the Colon & Rectum Volume 59: 3 (2016)
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CONCLUSIONS: Diverticular abscesses represent complicated diverticulitis and are associated with a high risk of recurrences and disease complications. Recurrences (contrary to other series) were often more severe than the index presentation. The successful CTguided drainage of a diverticular abscess does not appear to lower the risks of future recurrence or complication rates and frequently is only a bridge to surgery. After initial successful nonoperative management, patients with diverticular abscess should be offered interval elective colectomy (see Video, Supplemental Digital Content 1, http://links.lww.com/DCR/A216).
KEY WORDS: Diverticular abscess; Recurrence rates; Complications; Fistula; Stricture; Percutaneous drainage; Complicated diverticulitis; Modified Hinchey grade IB and II; Management; Surgery; Resection; Colectomy; Observation.
D
iverticulitis with abscess formation, that is, complicated diverticulitis of intermediate severity, remains a remarkably uncharted territory with regard to its best management. In contrast, there is broad consensus that medical therapy is the default choice for uncomplicated diverticulitis, as is immediate surgery for the most severe emergency presentations of acute diverticulitis (macroperforation, diffuse peritonitis, or obstruction).1 The increasingly recognized group in between of ≈25% of the patients on cross-sectional imaging show evidence of complicated diverticulitis with abscess formation.2–4 Current strategies start with antibiotics and possible CT-guided drainage (CGD) but if unsuccessful proceed to surgery during the same admission. Those with resolution of symptoms (signs of sepsis and of the abscess itself), however, are managed very differently from institution to institution, with some being recommended an elective operation.5 Until a decade ago, an elective sigmoid resection was recommended after 2 episodes of uncomplicated diverticulitis and after even a single attack of complicated but nonemergency diverticulitis in an attempt to prevent more severe disease in the event of a recurrence.6–8 This strategy has since been called into question by decision–analysis models, as well as by a number of reports suggesting that the first episode of diverticulitis is typically the most severe one and that patients with a history of more than 2 previous episodes of diverticulitis were at no greater risk of surgical morbidity or mortality at the time of a complicated recurrence than were patients with 1 to 2 episodes before the eventual surgery.9–11 Nonetheless, the most recent practice parameters of the American Society of Colon and Rectal Surgeons for the management of diverticulitis maintained that, in light of the high recurrence rates after initial nonoperative management of
complicated diverticulitis with abscess formation, an elective colectomy should be considered, particularly in those with a mesocolic or pelvic abscess of ≥5 cm.6–8 In 2014, we published a systematic review on the role of elective resection versus observation after nonoperative management of complicated diverticulitis with abscess formation and noted that identification of an abscess was associated with a high probability of resective surgery, whereas medical management frequently resulted in chronic or recurrent diverticular symptoms.12 However, it is generally acknowledged that the natural history of complicated diverticulitis beyond the index hospital stay has not been well analyzed. Contributing to the limitations in the literature are the lack of systematic and long enough follow-up in general, combined with the fact that patient cohorts to be followed are reduced to the individuals with more benign disease, whereas the worst cases are addressed with surgery and, hence, eliminated.11,13–15 As for the goal to prevent severe recurrent disease, as well as the likelihood of a stoma, the skewed data leave the surgeons without clear guidance about patient selection for and appropriate timing of elective resections. In the current communication, we attempted to address some of these issues by reviewing all of the cases of complicated diverticulitis at our institution within a 10-year period as defined by CT evidence of an abscess. The objectives of our analysis were as follows: 1) to define the impact of an abscess as evidence of complicated diverticulitis on the risk of failure of medical treatment, 2) to define the incidence and severity of recurrent attacks with a need for resective surgery, and 3) to determine the impact of CGD of the abscess. Our association with a major county hospital serving an indigent patient population with little ability to seek care outside of our facility offers an unparalleled opportunity to examine this question because of the lack of resources necessary to routinely offer elective sigmoid resection. We hypothesized that the rate of recurrent severe diverticulitis (defined as requiring more than just antibiotics) after seemingly resolved complicated diverticulitis with abscess is much higher than previously estimated in the literature.
PATIENTS AND METHODS Patient Population
Patients who were treated for acute diverticulitis between 2004 and 2014 at the Los Angeles County/University of Southern California Medical Center were identified and screened, and the disease was classified according to the modified Hinchey classification (Table 1).3,16 Included in our analysis and retrospectively analyzed were patients who, on CT, were reported to have evidence of diverticular abscess(es). Excluded were patients who were admitted primarily for stoma reversal after diverticular surgery;
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TABLE 1. Hinchey classification and modified Hinchey classification of acute diverticulitis3,16 Hinchey classification
Modified Hinchey classification 0
I
Pericolic abscess or phlegmon
II
Pelvic, intra-abdominal, or retroperitoneal abscess Generalized purulent peritonitis Generalized fecal peritonitis
III IV
IA IB II III IV FIST OBST
Mild clinical diverticulitis LLQ pain, fever No confirmation by elevated WBC, imaging, or surgery Confined pericolic inflammation, phlegmon Confined pericolic abscess Pelvic, distant intra-abdominal, or retroperitoneal abscess Generalized purulent peritonitis: no open communication with bowel lumen Fecal peritonitis: free perforation, open communication with bowel lumen Colovesical/colovaginal/coloenteric/colocutaneous fistula formation Stricture with large and/or small bowel obstruction
FIST = fistula formation; OBST = obstruction; LLQ = lower left quadrant; WBC = white blood cell.
atients who, in the hospital course, were found to have a p colon cancer that mimicked acute diverticulitis; or patients with relevant data deficiencies. The full electronic medical charts and CT images were reviewed and the following data entered into a datasheet generated with Microsoft Excel 2010: patient demographics, symptoms and duration of symptoms, past history of diverticulitis, comorbidities, previous abdominal surgery, clinical signs, white blood cell counts, abscess size, recurrence, and disease complications. Primary outcome measures were overall recurrence and disease complication rates, as well as the need for a subsequent operation after initial successful nonsurgical management. Evaluation was carried out for the whole cohort, as well as for the subgroup of patients with percutaneous drainage for diverticular abscess. The study protocol and data collection were approved by the institutional review board of the University of Southern California and were consistent with Health Insurance Portability and Accountability Act of 1996 regulations.
patients developed purulent or feculent peritonitis during the index hospitalization and were therefore reclassified as modified Hinchey III and IV. The patient characteristics at the time of the index admission are shown in Table 2. The overall average abscess size was 4.0 ± 2.4 cm (median, 3.7 cm; range, 0.5–14.0 cm). There was no mortality recorded in the cohort. Total length of stay was 7.0 ± 9.7 days (median, 4.0 days; range, 1.0–85.0 days). Average followup was 13.6 ± 9.3 months (median, 12.0 months; range, 3.0–70.0 months). Index Hospitalization
Of all 210 patients with diverticular abscesses at the time of the index admission, 25 patients (11.9%) required an urgent operation. This nonelective setting was associated with 80% of the surgeries being performed with the Hartmann procedure with creation of an end colostomy and a substantially longer length of hospital stay (24.3 ± 27.1 days; median, 13.0 days; range, 5.0–85.0 days). CGD was
Statistical Analysis
TABLE 2. Characteristics of 210 patients with diverticular abscess
Results were reported in descriptive statistics using SigmaPlot 13.0 software (Systat Software Inc, San Jose, CA) and expressed as mean ± SD or median with range. Statistical analysis was performed to compare groups or parameters using the χ2 test or the Fisher exact test for nominal variables and the Mann-Whitney rank-sum test or Student t test for continuous variables. Observed differences were considered statistically significant if p < 0.05.
RESULTS
Index hospital stay
Median age, y Sex, women/men Previous episodes of diverticulitis, n (%) ASA classification, n (%) Class I Class II Class III Unclassified Length of stay, mean ± SD, d
45 (range 18–87) 140/70 29 (14%)
Abscess size, mean ± SD, cm
Patient Characteristics
During the study period, 1194 patients presented with acute diverticulitis to Los Angeles County/University of Southern California Medical Center, a large metropolitan county hospital. On the basis of the modified Hinchey classification (Table 1), 210 patients met the inclusion criteria because they had CT evidence for a diverticular abscess. The majority of patients had a pericolonic (stage IB, 48%) or a pelvic abscess (stage II, 42%); in addition, 17 and 5
Characteristic
CT drain placement, n (%) Success, n/N (%) Failure, n (%) Modified Hinchey classification, n (%)a IB II III IV
50 (24) 111 (53) 32 (15) 17 (8) 7.0 ± 9.7 (median, 4.0; range, 1.0–85.0) 4.0 ± 2.4 (median 3.7, range 0.5 – 14.0) 65 (31) 61/65 (93.8) 4 (6.2) 100 (48) 88 (42) 17 (8) 5 (2)
Modified Hinchey classification as previously published.3,16
a
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All cases of acute diverticulitis (n = 1194) CT documented abscess (n = 210) Nonoperative management (n = 185)
Urgent operation (n = 25)
Recurrent diverticulitis (n = 112) Urgent operation (n = 29)
No documented recurrence (n = 73)
Subsequent operation (n = 37)
Operation attributed to ideology (n = 1)
Chronic complication (obstruction, fistula, smoldering) (n = 31)
Ideology (n = 6)
FIGURE 1. Flow chart of management of the entire cohort of patients with acute diverticulitis.
performed in 65 (31%) of 210 patients. The abscess size in the group with CGD was 6.5 ± 2.8 cm (median, 6.0 cm; range, 1.1–14.0 cm), significantly larger than 3.4 ± 1.7 cm (median, 3.0 cm; range, 0.5–10.2 cm) in the group who were managed without CGD (p < 0.05). A total of 93.8% of CGDs were successful and resulted in resolution of the acute symptomatology (white blood cell count, fever, pain, and tachycardia); it failed to resolve the diverticulitis attack in 4 patients who subsequently required an urgent operation. In contrast, 185 of 210 patients with abscesses were successfully managed medically using antibiotics with/without CGD (Fig. 1) and eventually were discharged from the hospital after a significantly shorter length of stay of 5.1 ± 4.6 days (median, 4.0 days; range, 1.0–28.0 days; p < 0.05).
(colovesicular/colovaginal/colocutaneous) and recurrent abscesses were the 2 most frequent complications affecting 39.4% and 45.1% of the patients. The majority of the 29 fistulas in 28 patients were to the bladder (n = 15), followed by fistulas to the vagina (n = 5) and enterocutaneous fistulas (n = 5), which were typically related to the CGD tract; the rest were internal fistulas. Fifty one of the patients (45.6%) had a more severe episode at recurrence, reflected by an increased modified Hinchey class when compared with the original stage at the time of the index hospitalization. TABLE 3. Characteristics of recurrences of diverticulitis (N = 112 patients)
Recurrent Diverticulitis
Of the 185 patients who were successfully treated nonoperatively during the index hospital stay and discharge from the hospital, 112 (61%) subsequently developed recurrent diverticulitis after an average of 5.4 ± 6.1 months (median, 3.5 months; range, 0.8–36.0 months); 47 (42%) of 112 individuals experienced more than 1 episode (Table 3). At the time of the recurrence, 63% of the patients showed complicated diverticulitis (Fig. 2), whereby fistula formation
Characteristic
At time of recurrence
Time to recurrence, mean ± SD, mo
5.4 ± 6.1 (median, 3.5; range, 0.8–36.0) 13.6 ± 9.3 (median, 12.0; range, 3.0–70.0) 47 (42) 51 (45.6)
Follow-up, mean ± SD, mo Multiple recurrences, n (%) Increase in modified Hinchey class, n (%) Characterization of recurrence, n (%) Complicateda Uncomplicatedb
71 (63.4) 41 (36.6)
Complicated indicates recurrent abscess, fistula, obstruction, peritonitis (modified Hinchey IB or higher). Uncomplicated indicates modified Hinchey class IA.
a
b
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Devaraj et al: Recurrence After Diverticular Abscess
IB (n = 8)
II (n = 21)
III (n = 8)
Recurrent diverticulitis (n = 112)
Complicated (n = 71) 63.4%
IV (n = 1)
Fistula (n = 25) Uncomplicated (modified Hinchey IA) (n = 41) 36.6%
Obstruction (n = 4)
IB + fistula (n = 1)
Combination (n = 4)
II + fistula (n = 2)
IB + obstruction (n = 1)
FIGURE 2. Flow chart of operative management.
The original abscess size in patients who later developed recurrences was significantly larger than in the patients who did not develop recurrence (5.3 ± 2.8 vs 3.2 ± 1.4 cm; p < 0.001). Twenty nine (26%) of 112 patients with recurrences required an urgent operative intervention because of the acuity of presentations. An additional 37 patients eventually underwent an elective colectomy whereby the indication in 31 patients (28%) was based on complications of the recurrence with stricturing and large bowel obstruction, fistula formation, smoldering symptoms, or combinations thereof (Fig. 2). Only the remaining 6 patients had a resection performed based on ideology, that is, the recommendation to perform an elective surgery to prevent future attacks (Figs. 1 and 3). Overall Risk to Require Surgery
Complicated diverticulitis as characterized by CT presence of an abscess was associated with a 25.7% risk (54 of 210 patients) of needing an urgent operation, either during the index admission or a subsequent recurrent attack (Fig. 3). In the urgent surgery setting (59% of all surgeries), Hartmann procedure with stoma dominated primary anastomosis, with 56% and 44%. Within the follow-up period, a total of 92 (44.0%) of the 210 patients eventually underwent an operation at our institution, with an overall 36.9% probability
of a stoma; it is unknown although whether and how many additional patients had surgeries carried at other institutions. The indication for the overwhelming majority of performed operations (92% (85 of 92)) was based on the severe and nonresolving acute or chronic nature of the disease as stated above; in contrast, only 7 patients (8%) underwent a surgery based on their history rather than active symptomatology (ideology indication). A total of 97.3% of all elective operations were carried out with a primary anastomosis. Impact of CGD
Although CGD of diverticular abscesses, as stated previously, had a high initial success rate of 93.8% (61 of 65 patients) during the index admission (Fig. 4), a substantial proportion of 45 (74.0%) of 61 patients developed a recurrence. Of these 45 patients, 71% presented again with complicated diverticulitis with abscess, fistula, obstruction, or peritonitis. Five (8.2%) of the 61 patients developed a colocutaneous fistula along the drain track. Twenty five (55.6%) of the 45 patients with recurrence after CGD required a surgical intervention.
DISCUSSION The natural history of patients with complicated diverticulitis and diverticular abscess formation is still poorly
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All patients with abscess (n = 210)
Total surgery (n = 92)
Ideology (n = 6+1)
Chronic complications (n = 31)
Urgent presentation (n = 54)
FIGURE 3. Flow chart of characteristics of recurrent diverticulitis.
understood, both during the index hospital stay and even more after successful initial nonoperative management.12 The necessity of an elective resection versus continued observation after an episode of complicated diverticulitis is under debate.12,17,18 Arguments against elective surgery after an acute episode of nonspecified diverticulitis have been made in different ways (based on the disease behavior and the morbidity of a surgery as such). Decision analysis models, as well as a number of retrospective studies, suggested that the risk of subsequent more severe attacks was low and did not warrant an elective resection9,11,13; however, several limitations had not been sufficiently considered, most notably the uncertain follow-up in patient populations with a nonmalignant disease on one hand and the fact that, often, surgical intervention had eliminated the patients with the worst disease from Total CGD (n = 65)
Immediate failure requiring urgent opera on (n = 4 (6%))
Ini al success (n = 61 (94%))
Recurrence (n = 45 (74%))
No recurrence (n = 16 (26%))
Complicated (n = 32 (71%))
Uncomplicated (n = 13 (29%))
FIGURE 4. Outcomes of CT-guided drainage (CGD).
the cohorts and, hence, artificially lowered the true recurrence risk.14,15 With more specific focus on patients with complicated diverticulitis, some authors argued that even those patients can and should be managed medically.19–22 These mostly retrospective studies were generally limited by small sample size and varying treatment philosophies, such that definitive conclusions were difficult to ascertain.12 Gaertner et al19 analyzed a subgroup of 32 patients with severe medical comorbidities who underwent percutaneous drainage but were deemed too high risk for a subsequent colectomy. They reported a recurrence-free survival of 58% at 7.4 years.19 The characteristics of this very small study population preclude widespread extrapolation of its results. In addition, when all of the patients from the original study group (n = 218) were analyzed, the colectomy-free survival was only 17%, hence making it difficult to use that study in support of a nonoperative strategy. Our recently published systematic review of 22 studies with a total of 1051 patients with diverticular abscess found that only 28% of patients did not undergo surgery or have a recurrence during follow-up and that recurrence rates were 39% even in patients awaiting elective resection.12 The 2014 American Society of Colon and Rectal Surgeons practice parameters for the treatment of sigmoid diverticulitis strongly recommend elective colectomy after an episode of complicated diverticulitis.6 In our current study, we attempted to find answers to some of these important issues by retrospective review of a comparably large patient cohort with CT evidence of an abscess. As stated in the introduction, the limitations of institutional resources on one hand and of patient access to other healthcare facilities on the other hand allowed for a rare study of the natural course of the disease. Because of significant resource limitations, routine or expeditious elective colectomy on patients after an episode of complicated diverticulitis is difficult to implement. Furthermore, the indigent patient population has little ability to seek care outside of our facility except in emergencies. We therefore have reason to believe that the presented numbers of recurrences and necessary surgeries are representative of the disease and, if at all, underestimate rather than overestimate those events. From the preceding 10 years from 1994 to 2004, we previously reported a recurrence rate of 42% in patients with medically managed diverticular abscess.3 Our current study, with 210 patients and, hence, more than double the original study population, showed an even higher documented recurrence rate of ≥61%; a total of 44% underwent a colectomy at our institution, whereby 54% of patients who developed recurrent disease after initial medical management were unable to avoid an operative intervention, and 26% required even an urgent operation. This number represents a minimum and could even be higher with longer follow-up; if our assumption that patients would,
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by necessity, come back to our institution was incorrect and/or they were seeking emergency care elsewhere; or if some were lost to follow-up. Furthermore, contrary to the reported belief that recurrent episodes tend to be milder than the first attack,10,22–25 we found that 63% of the recurrent episodes were complicated by abscess, peritonitis, fistula, and/or obstruction. In fact, 45.6% of the recurrences were more severe than at the time of the index presentation, as evidenced by an upstage from the original modified Hinchey class. Thus, for a significant proportion of these patients, watchful waiting proved to be detrimental and was associated with a substantially higher colostomy rate (56%) than if an elective resection had been contemplated and performed (3%). In addition, these complications can lead to recurrent hospitalizations, decreased quality of life, lost wages, and increased healthcare costs. With the advent of CT-guided percutaneous drainage, some authors advocate a nonoperative approach to patients who were successfully treated during the index admission.18,19,21,26–31 Although CGD is highly successful at avoiding the need for emergent operation, it does not appear to reliably prevent overall recurrences or additional disease complications. Paradoxically, larger abscesses were more likely drainable by CGD on one hand, but the larger abscess size might suggest a more advanced disease process on the other hand. This would explain that a nonnegligible number of individuals in our study developed a colocutaneous fistula along the drain track (an observation not reported previously in other studies); only 26% of the patients remained disease-free after the initial CGD. Therefore, patients with even successful percutaneous drainage of a diverticular abscess should be cautioned that it might not be a definitive management but rather a bridge to interval elective colectomy. Our study represents one of the largest series to date looking at the long-term outcome of patients who were medically managed after complicated diverticulitis. The limitations of our study are its retrospective nature and relatively short follow-up, the latter of which in fact would emphasize the high recurrence risk. The median time to recurrence in our study is only 3.5 months (range, 0.8–36.0 months), which suggests that at least some proportion of patients had smoldering disease despite having resolved the acute episode and meeting discharge criteria on index admission. Given the retrospective nature of the study, however, it is difficult to decipher the exact percentage of such patients, and the reasons are subject to speculation (disease, patient, and compliance related). Nevertheless, we feel that both smoldering and recurrent disease highlight the complexity of diverticular abscesses. Hence, our findings not only illustrate the high incidence of recurrent attacks but also of complications associated with those recurrences. These complications increase morbidity and the probability of a stoma, all of which could potentially be prevented with timely elective interval colectomy.
Devaraj et al: Recurrence After Diverticular Abscess
CONCLUSION Diverticular abscesses represent complicated diverticulitis and are associated with a higher than previously reported risk of recurrences and disease complications. Recurrences (contrary to other series) were often more severe than the index presentation. Successful CGD of diverticular abscess does not appear to lower the risks of future recurrence or complication rates and may only be a bridge to surgery. After initial successful nonoperative management, patients with diverticular abscess should be offered interval elective colectomy. ACKNOWLEDGMENT We are indebted to Michael Ruiz for his constructive support in preparing this article and the computer skills to generate presentable tables and graphs. REFERENCES 1. Kaiser AM. McGraw-Hill Manual: Colorectal Surgery. http://accesssurgery.com/resourceToc.aspx?resourceID=211; Accessed April 12, 2015. 2. Ambrosetti P, Robert J, Witzig JA, et al. Incidence, outcome, and proposed management of isolated abscesses complicating acute left-sided colonic diverticulitis: a prospective study of 140 patients. Dis Colon Rectum. 1992;35:1072–1076. 3. Kaiser AM, Jiang JK, Lake JP, et al. The management of complicated diverticulitis and the role of computed tomography. Am J Gastroenterol. 2005;100:910–917. 4. Schoetz DJ Jr. Diverticular disease of the colon: a century-old problem. Dis Colon Rectum. 1999;42:703–709. 5. Alvarez JA, Baldonedo RF, Bear IG, et al. Presentation, management and outcome of acute sigmoid diverticulitis requiring hospitalization. Dig Surg. 2007;24:471–476. 6. Feingold D, Steele SR, Lee S, et al. Practice parameters for the treatment of sigmoid diverticulitis. Dis Colon Rectum. 2014;57:284–294. 7. Rafferty J, Shellito P, Hyman NH, et al. Practice parameters for sigmoid diverticulitis. Dis Colon Rectum. 2006;49:939–944. 8. Wong WD, Wexner SD, Lowry A, et al. Practice parameters for the treatment of sigmoid diverticulitis–supporting documentation: the Standards Task Force–the American Society of Colon and Rectal Surgeons. Dis Colon Rectum. 2000;43:290–297. 9. Salem L, Veenstra DL, Sullivan SD, et al. The timing of elective colectomy in diverticulitis: a decision analysis. J Am Coll Surg. 2004;199:904–912. 10. Chapman JR, Dozois EJ, Wolff BG, et al. Diverticulitis: a progressive disease? Do multiple recurrences predict less favorable outcomes? Ann Surg. 2006;243:876–883. 11. Chapman J, Davies M, Wolff B, et al. Complicated diverticulitis: is it time to rethink the rules? Ann Surg. 2005;242:576–581. 12. Lamb MN, Kaiser AM. Elective resection versus observation after nonoperative management of complicated diverticulitis with abscess: a systematic review and meta-analysis. Dis Colon Rectum. 2014;57:1430–1440.
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23. van de Wall BJ, Draaisma WA, Consten EC, et al. Does the presence of abscesses in diverticular disease prelude surgery? J Gastrointest Surg. 2013;17:540–547. 24. Nelson RS, Ewing BM, Wengert TJ, et al. Clinical outcomes of complicated diverticulitis managed nonoperatively. Am J Surg. 2008;196:969–974. 25. Ritz JP, Lehmann KS, Frericks B, et al. Outcome of patients with acute sigmoid diverticulitis: multivariate analysis of risk factors for free perforation. Surgery. 2011;149:606–613. 26. Felder SI, Barmparas G, Lynn J, et al. Can the need for colectomy after computed tomography-guided percutaneous drainage for diverticular abscess be predicted? Am Surg. 2013;79:1013–1016. 27. Hall J. Should elective colectomy be routine following percutaneous drainage of a diverticular abscess? Dis Colon Rectum. 2013;56:533–534. 28. Singh B, May K, Coltart I, et al. The long-term results of percutaneous drainage of diverticular abscess. Ann R Coll Surg Engl. 2008;90:297–301. 29. Brandt D, Gervaz P, Durmishi Y, et al. Percutaneous CT scan-guided drainage vs. antibiotherapy alone for Hinchey II diverticulitis: a case-control study. Dis Colon Rectum. 2006;49:1533–1538. 30. Durmishi Y, Gervaz P, Brandt D, et al. Results from percutaneous drainage of Hinchey stage II diverticulitis guided by computed tomography scan. Surg Endosc. 2006;20:1129–1133. 31. Siewert B, Tye G, Kruskal J, et al. Impact of CT-guided drainage in the treatment of diverticular abscesses: size matters. AJR Am J Roentgenol. 2006;186:680–686.
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