Increasing the number of attacks increases the conversion ratein laparoscopic diverticulitis surgery

Karin Cole Æ Steven Fassler Æ Sree Suryadevara ÆD. Mark Zebley

Received: 10 December 2007 / Accepted: 3 May 2008 / Published online: 5 June 2008

� Springer Science+Business Media, LLC 2008

Abstract

Background This study aimed to determine whether the

number of diverticulitis or complicated diverticulitis episodes

affects the conversion rate or postoperative complication rate

in elective laparoscopic sigmoid colectomy.

Methods In this study, 216 charts were reviewed for

baseline characteristics, diverticulitis history, and intra-

and postoperative complications. Analysis was performed

with the Student’s t-test, the chi-square test, and Fisher’s

exact tests.

Results Of 216 sigmoid colectomies, 151 were laparo-

scopic, 19 were converted, and 46 were open. Baseline

characteristics were similar for patients with zero to two

and those with three or more inpatient diverticulitis attacks.

Patients with uncomplicated diverticulitis had a higher rate

of conversion after three or more inpatient episodes (2.6%

vs 25%; p = 0.04). There was no difference in operative

times or postoperative complication rates. Patients with a

history of abscess had a 23% chance of conversion. Those

with no abscess history had an 8% chance of conversion

(p = 0.02). In general, converted procedures required more

time than open procedures but were associated with

decreased hospital length of stay (LOS) and a decreased

rate of postoperative ileus.

Conclusion Multiple inpatient diverticulitis attacks and a

history of abscess were associated with laparoscopic con-

version. Converted procedures required more time than

open procedures, but had reduced LOS and postoperative

ileus. Laparoscopic sigmoid colectomy can be attempted

safely for patients with three or more inpatient attacks or a

history of complicated diverticulitis.

Keywords Complicated diverticulitis � Conversion �Diverticulitis � Laparoscopic colorectal surgery �Sigmoid colectomy

Laparoscopic colectomy for sigmoid diverticulitis was first

introduced in the 1990s. Since then, studies have demon-

strated it to be a safe and effective alternative to open

surgery for this condition [1–8]. The effect of diverticular

complications, such as abscess, on the feasibility of lapa-

roscopic resection has been investigated by several authors,

who have found that the rate of conversion to open

resection is higher [4–7, 9]. No studies, however, have

addressed the effect of multiple, uncomplicated attacks of

diverticulitis requiring inpatient hospitalization.

Patients with a history of multiple diverticulitis attacks

severe enough to require inpatient care might be expected

to have more severe or more extensive inflammatory

changes than patients who present for surgery after only

one or two inpatient attacks.

We hypothesized that patients with a history of multiple

hospitalizations for diverticulitis would experience a longer

operation time, a higher conversion rate, or a higher post-

operative complication rate than patients with a history of

milder disease. We undertook a retrospective study of

patients undergoing elective surgery for diverticulitis at a

large community teaching hospital to address this

hypothesis.

K. Cole (&) � S. Fassler � S. Suryadevara � D. M. Zebley

Department of Surgery, Abington Memorial Hospital,

Price Medical Office Building, Suite 604, 1245 Highland

Avenue, Abington, PA 19001, USA

e-mail: kcole@amh.org

123

Surg Endosc (2009) 23:1088–1092

DOI 10.1007/s00464-008-9975-z

Methods

We performed a retrospective chart review of 216 elective

sigmoid colectomies for diverticulitis performed between

January 1996 and July 2006. Data sources included the hos-

pital’s electronic medical record, outpatient charts, and patient

information databases prospectively maintained by the two

laparoscopic colorectal surgeons. The data collected included

baseline demographics, diverticulitis history (including the

number of inpatient and outpatient episodes and the presence

of complications such as abscess, fistula, stricture, or perfo-

ration), operative time, type of operation, intraoperative

complications, hospital length of stay (LOS), postoperative

complications, and readmission within 30 days of surgery.

Hand-assisted operations (2 in 151) were considered to

have been completed laparoscopically. Converted cases

were those in which a laparotomy was necessary to com-

plete some or all of the open dissection. All patients

underwent a standard mechanical bowel preparation with

parenteral antibiotics administered preoperatively and for

24 h postoperatively. All laparoscopic and converted cases

were managed by one of two fellowship-trained colorectal

surgeons (M.Z. and S.F.) along with a resident assistant.

Three trocars (one umbilical and two on the right side of

the abdomen) were used, and a left lower quadrant incision

was created for specimen removal. A fourth trocar was

inserted occasionally for difficult dissections. Dissection of

the sigmoid colon mesentery proceeded from medial to

lateral or from lateral to medial, depending on the extent

and location of the patient’s disease.

The Student’s t-test was used for comparison of para-

metric data. The chi-square test and Fisher’s exact test

when appropriate were used for comparison of nonpara-

metric data. Open source statistical software was used for

some calculations. All p values are two-tailed and con-

sidered significant at a level less than 0.05. The study was

approved by the hospital’s institutional review board.

Results

Of the 216 charts reviewed, 151 (70%) described opera-

tions completed laparoscopically, 19 (9%) described

operations converted to open procedures, and 46 (21%)

described operations performed as open procedures. Dur-

ing the study period, the number of cases managed per

month increased from 1.5 (January 1996 to December

1999) to 3.6 (January 2003 to July 2006). The percentage

of cases managed laparoscopically increased from 39% to

89% during the same period (Fig. 1).

Open cases were managed by 1 of 14 general surgeons.

Laparoscopic cases were predominantly managed during

the later part of the study period, and open cases during the

earlier part. There was a transition period during which

open and laparoscopic approaches both were used with

similar frequency (October 1997 to April 2000). During

this period, the approach offered to each individual patient

was dependent on the type of surgeon to whom the patient

had been referred (general vs colorectal) and not on the

presumed extent of the patient’s disease.

The overall conversion rate was 11.2%. There was some

variation in the conversion rate by time period. During the

first part of the study (October 1997 to December 1999),

the conversion rate was 10%, whereas during the second

part (January 2000 to December 2003), it was 8.7%, and

during the third part (January 2004 to July 2006), it was

13.6%.

The reason for conversion in all but four cases was

inflammation or adhesions. Two of these four cases were

converted because of bleeding and two because of persis-

tent anastomotic leaks.

For 138 (81%) of the 170 patients who underwent lap-

aroscopic or converted procedures, complete information

on their diverticulitis history was available. This part of the

analysis excluded 54 of these patients because of compli-

cated diverticulitis (phlegmon, abscess, fistula, stricture),

leaving 84 patients with a well-documented history of

uncomplicated diverticulitis.

The patients were classified according to the number of

hospitalizations for diverticulitis before elective surgery

(B2 vs C3 episodes). For the patients who underwent

elective sigmoid resection after no hospitalizations or only

one hospitalization, the indication for surgery was typically

a chronic, relapsing course of disease managed in the

outpatient setting.

Fig. 1 Sigmoid colectomy cases per month (line) and percentage of

cases begun laparoscopically (bar) during two periods

Surg Endosc (2009) 23:1088–1092 1089

123

Baseline characteristics were compared between

patients with zero to two hospitalizations and those with

three or more hospitalizations for diverticulitis (Table 1).

Patients in the group with three or more hospitalizations

were approximately 12 years older than the patients in the

group with fewer attacks. Other characteristics (body mass

index [BMI], sex, rates of prior open abdominal and pelvic

surgery) were similar.

Patients with a history of zero to two inpatient divertic-

ulitis attacks had a conversion rate of 2.6%, whereas those

with three or more attacks had a conversion rate of 25%

(Table 2). When these two groups were compared, the dif-

ference was found to be statistically significant (p = 0.04).

The operative time for laparoscopic cases did not differ

significantly according to number of attacks. The postop-

erative complications were infrequent and did not seem

related to the number of prior inpatient diverticulitis attacks.

The most frequent indication for surgery for compli-

cated diverticulitis was abscess (21% of all patients, 47%

of patients with complicated disease). Patients presenting

with a history of diverticular abscess were compared with

patients who had no history of abscess. Patients with an

abscess history had a 23% chance of requiring conversion

to an open procedure, whereas patients with no abscess

history had an 8% chance of such conversion. This dif-

ference was found to be statistically significant (p = 0.02).

Patients with a history of abscess, whether they underwent

laparoscopic or converted procedures, had an operation

time and LOS similar to those of patients without abscess

(Table 3).

When all the patients undergoing converted procedures

were compared with all the patients undergoing open

procedures, a statistically significant difference in opera-

tion times (158 vs 125 min; p = 0.003) was found. The

rates of postoperative ileus also showed a difference (5%

for the converted group vs 15% for the open group), but

this difference did not reach statistical significance, nor did

the average hospital LOS (7 days for the converted group

vs 7.9 days for the open group).

Discussion

Prior studies have demonstrated the safety of a laparoscopic

approach to sigmoid colectomy for diverticulitis [1–8]. The

findings also show that the safety profile of the procedure

increases with increasing institutional experience [10–12].

This review of laparoscopic sigmoid resection for diver-

ticulitis at our institution demonstrated that as institutional

experience increased, the number of resections performed

per month also increased, despite the fact that only two

surgeons performed most of these resections (compared

with 14 surgeons who performed open resections in pre-

ceding years). This suggests that patient referrals increased

or patients’ willingness to undergo a recommended resec-

tion increased with the availability of laparoscopic resection

at our institution.

Our overall conversion rate of 11.2% is within the range

of rates reported in the literature (5.2–26%) [1, 2, 7, 11,

13]. Multiple risk factors influencing the need for conver-

sion to an open procedure have been reported previously

including male sex, advanced age, high BMI, surgeon

experience, and the presence of complicated diverticular

disease [7, 11–13]. A previously published report from our

institution considering patients undergoing laparoscopic

colorectal surgery for any indication demonstrated not only

a higher conversion rate in the presence of prior abdominal

surgery but also a higher rate of inadvertent enterotomy,

postoperative ileus, and reoperation [14]. The effect of

multiple uncomplicated diverticulitis episodes on the need

for conversion to an open procedure, however, has not been

reported previously. This was the focus of our data

collection.

Table 1 Characteristics of patients with 0–2 versus 3 or more hos-

pitalizations for diverticulitis before elective sigmoid resection

0–2 inpatient

attacks

3 or more

inpatient attacks

p-value

Age 53.2 64.9 \0.05

Sex: %male 51.3 37.5 NS

BMI 27.6 26.9 NS

Abdominal surgery (%) 31.5 37.5 NS

Pelvic surgery (%) 26.3 25 NS

NS, not significant

Table 2 Conversion rate according to number of prior inpatient

diverticulitis attacksa

No. of inpatient diverticulitis attacks

0 1 2 3 4+

Conversion rate (%) 5.3 0 4.3 25 25

a p = 0.04 for comparison of 0–2 attacks versus 3 or more attacks

Table 3 Comparison of conversion rate, operation time, and length

of stay for patients with and without a history of abscess undergoing

laparoscopic or converted resection

Abscess No abscess p-value

Conversion rate (%) 23 8 0.02

Lap OR time (min) 141 127 NS

Converted OR time (min) 156 159 NS

Lap LOS (days) 4.2 4.4 NS

Converted LOS (days) 6.9 7.1 NS

Lap, laparoscopic; OR, operation; NS, not significant; LOS, hospital

length of stay

1090 Surg Endosc (2009) 23:1088–1092

123

We hypothesized that an increasing number of hospital-

izations, even in the absence of diverticular complications,

would have an effect on conversion rate, operative time, or

complications due to the presence of more severe or more

extensive inflammatory changes. Although the retrospective

nature of the study limited our ability to collect detailed data

for all patients, we were able to analyze complete data from

84 cases. This demonstrated a trend toward a higher con-

version rate for patients who had a greater number of

inpatient diverticulitis attacks, with an apparent cutoff point

between two and three attacks. When this cutoff point was

chosen for further analysis, a statistically significant differ-

ence in conversion rates was demonstrated.

The appropriate timing of elective surgery for divertic-

ulitis has been a matter of debate in the literature

essentially ever since the topic was first addressed. The

most recent guidelines from the American Society of Colon

and Rectal Surgeons acknowledge that resection usually is

offered to patients after two uncomplicated attacks of

diverticulitis [15]. Our finding of a higher conversion rate

for patients who have had more than two attacks strongly

supports these guidelines. Patients presenting for elective

laparoscopic resection after more than two inpatient div-

erticulitis attacks should be counseled that they are more

likely to require conversion to an open procedure.

Several investigators have established the feasibility of

laparoscopic resection for patients with a history of com-

plicated diverticulitis [4–7, 9]. Our results were in

agreement with their findings. Although a history of abscess

increases the rate for conversion to an open procedure, it

does not result in a longer operation time, an increased LOS,

or an increased complication rate. These results suggest

that, at least in the case of diverticulitis, converting a lap-

aroscopic procedure to an open one has few, if any,

disadvantages compared with starting a case in an open

fashion. Our findings of a decreased LOS and a decreased

rate of postoperative ileus in the converted group compared

with the open group further support this conclusion.

Although these findings were not statistically significant,

we believe that the latter, at least, is clinically significant.

Our study does have several limitations. It is a single-

institutional experience, with data collected retrospectively

for the most part. Obtaining a detailed diverticulitis history

for each patient was especially challenging. The use of

multiple data sources, however, including hospital and

outpatient records, allowed us to compile the necessary

data for a sufficiently large group of patients to permit

statistical analysis.

Another factor that should be considered in the inter-

pretation of our results is the presence of a learning curve

for the two laparoscopic surgeons within the study period.

Although variations in conversion rate were relatively

minor over the course of the study period and did not seem

related to the accumulation of experience by the two lap-

aroscopic surgeons whose patients formed the study group,

an analysis of recently completed cases could yield dif-

ferences in operation times and conversion rates. It is

difficult to speculate whether these differences would be

significant or not.

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