International Journal of Gynecology and Obstetrics 122 (2013) 108–111

Contents lists available at SciVerse ScienceDirect

International Journal of Gynecology and Obstetrics

j ourna l homepage: www.e lsev ie r .com/ locate / i jgo

CLINICAL ARTICLE

A case–control study of risk factors for ileus and bowel obstruction following benigngynecologic surgery☆

Danielle D. Antosh a,⁎, Cara L. Grimes b, Aimee L. Smith c, Sarah Friedman d,Brook L. Mcfadden e, Catrina C. Crisp f, Arielle M. Allen g, Robert E. Gutman a,Rebecca G. Rogers e; for the Fellows’ Pelvic Research Networka Department of Obstetrics and Gynecology, Division of Female Pelvic Medicine and Reconstructive Surgery, MedStar Washington Hospital Center, Washington, USAb Department of Reproductive Medicine, Division of Female Pelvic Medicine and Reconstructive Surgery, University of California, San Diego, USAc Division of Urogynecology and Reconstructive Pelvic Surgery, Cleveland Clinic Florida, Weston, USAd Division of Urogynecology and Reconstructive Pelvic Surgery, Johns Hopkins University and Greater Baltimore Medical Center, Baltimore, USAe Division of Urogynecology, University of New Mexico Health Sciences Center, Albuquerque, USAf Division of Urogynecology and Reconstructive Pelvic Surgery, Good Samaritan Hospital, Cincinnati, USAg Division of Female Pelvic Medicine and Reconstructive Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, USA

☆ Abstract presented at the 38th AnnualMeeting of the SApril 13–15, 2012; Baltimore, MD, USA. Antosh DD, GriMcFadden BL, Smith A, et al. Risk factors for ileus and bowgynecologic surgery: A Fellows’ Pelvic Research NetwReconstr Surg 2012;18(5S):S5.⁎ Corresponding author at: Center for Restorative Pe

Hospital, 6560 Fannin, Suite 2100, Houston, TX 77030fax: +1 713 791 5023.

E-mail address: ddantosh@tmhs.org (D.D. Antosh).

0020-7292/$ – see front matter © 2013 International Fedhttp://dx.doi.org/10.1016/j.ijgo.2013.03.014

a b s t r a c t

a r t i c l e i n f o

Article history:

Received 14 November 2012Received in revised form 28 February 2013Accepted 19 April 2013

Keywords:Bowel obstructionGynecologyIleusRisk factorSurgery

Objective: To identify risk factors leading to the development of postoperative ileus and small-bowel obstruc-tion (SBO) after benign gynecologic surgery. Methods: In a multicenter case–control study across the UnitedStates, data were examined from women with International Classification of Diseases 9 (ICD-9) and CurrentProcedural Terminology (CPT) codes who underwent benign gynecologic surgery between January 2005 andJune 2010 and subsequently developed an ileus or SBO. Each patient with ileus or SBO was matched to 2control women who underwent the same benign gynecologic procedure but did not develop ileus or SBO.Results: During the study period, 144 cases and 288 controls were identified. By conditional multivariatelogistic regression, risk factors for ileus or SBO included cystotomy (odds ratio [OR], 8.7; 95% confidence in-terval [CI], 1.48–51.47), concomitant bowel surgery (OR, 4.3; 95% CI, 1.18–15.78), perioperative transfusion(OR, 2.9; 95% CI, 1.44–5.95), and lysis of adhesions (OR, 1.7; 95% CI, 1.03–2.83). Conclusion: Lysis of adhesions,

concomitant bowel surgery, and perioperative complications such as blood transfusion and cystotomy werefound to be risk factors for the development of ileus and/or SBO after benign gynecologic surgery.© 2013 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

1. Introduction

Postoperative bowel complications including ileus and small-bowelobstruction (hereafter ileus/SBO) are complications that contributeconsiderably to patient morbidity and a delay in hospital discharge[1]. Ileus/SBO has a significant economic burden on the healthcaresystem: the annual amount spent on ileus alone is estimated at US$750 million to US$ 1 billion [2]. Reducing postoperative hospital staywith an effective treatment or prevention strategy could significantlydecrease healthcare costs [3].

ociety of Gynecologic Surgeons;mes CL, Allen AM, Friedman S,el obstruction following benignork Study. Female Pelvic Med

lvic Medicine, The Methodist, USA. Tel.: +1 713 441 5800;

eration of Gynecology and Obstetrics.

The incidence of ileus/SBO varies depending on the type of surgi-cal procedure performed. The rate may be as high as 24.5% after colo-rectal surgery [4]. In gynecologic surgery, the rates of postoperativeileus/SBO range have been reported as 7%–18% after abdominal gyne-cologic surgery, 6% after abdominal sacrocolpopexy, and 2% aftervaginal hysterectomy [4–8].

Little advancement has been made in the identification of riskfactors for the development or prevention of ileus/SBO. Previouslyidentified risk factors associated with the development of ileus/SBOinclude older age and intraoperative factors such as blood loss andthe presence of small-bowel adhesions [7,9]. Many previous cohortstudies have focused on patients undergoing a specific procedure orroute that is not generalizable to routine gynecologic surgery. Preop-erative and intraoperative factors associated with the developmentof ileus/SBO in a heterogeneous population of gynecologic patientswith benign disease have yet to be identified. As a result, the aimof the present study was to identify, by using a case–control studydesign, risk factors leading to clinically significant postoperativeileus/SBO in a diverse population of gynecologic patients undergoingvarious surgical procedures.

Published by Elsevier Ireland Ltd. All rights reserved.

Table 1Characteristics of the study women.a

Cases(n = 144)

Controls(n = 288)

OR (95% CI)b

Age, y 48 ± 13 46 ± 13 1.02 (1.00–1.04)BMI 30.4 ± 9 29.7 ± 8.0 1.01 (0.99–1.04)Race

White 62 (49) 128 (47) Ref.Black 38 (30) 74 (27) 1.48 (0.80–2.71)Hispanic 9 (7) 39 (14) 0.33 (0.12–0.88)Asian 1 (1) 6 (2) 0.19 (0.02–1.88)Other 16 (13) 23 (9) 1.53 (0.66–3.57)

SmokingNever 95 (69) 202 (73) Ref.Previously 17 (12) 25 (9) 1.60 (0.83–3.09)Current 26 (19) 50 (18) 1.06 (0.61–1.85)

Postmenopausal status 45 (32) 71 (25) 1.90 (1.06–3.40)Prior abdominal surgery 100 (70) 173 (61) 1.62 (1.03–2.58)Prior bowel surgery 15 (11) 22 (8) 1.57 (0.80–3.07)CCI score 0.6 ± 1.0 0.4 ± 0.8 1.30 (1.02–1.65)

Abbreviations: BMI, body mass index (BMI, calculated as weight in kilograms dividedby the square of height in meters); CCI, Charlson comorbidity index; CI, confidenceinterval; OR, odds ratio.

a Values are given as mean ± SD or number (percentage) unless stated otherwise.b Odds ratio for univariate analysis.

109D.D. Antosh et al. / International Journal of Gynecology and Obstetrics 122 (2013) 108–111

2. Materials and methods

The present multicenter case–control study was conducted throughthe Fellows’ Pelvic Research Network and included women whounderwent benign gynecologic surgery between January 1, 2005, andJune 30, 2010, at 7 sites in the United States [10]. Ethical approval ofthe study was obtained from the appropriate Institutional ReviewBoards. Owing to the retrospective nature of the study, informed con-sent was not obtained.

Caseswere defined as patientswho underwent benign gynecologicsurgery and subsequently developed an ileus or SBO. As in a previousstudy, ileus and SBO were grouped together owing to their similarclinical presentation and were defined as any symptoms of nausea,vomiting, abdominal pain, and/or abdominal distention resulting ina prolongation of stay during an index hospitalization (≥2 days forlaparoscopic or vaginal surgery; ≥4 days for abdominal surgery),readmission, or reoperation within 1 year [7]. Each case womanwas matched to 2 control women who underwent the same benigngynecologic procedure closest in time at the same institution butdid not develop ileus/SBO. Women with gynecologic malignancieswere excluded.

Gynecologic surgical cases and controls were identified bymedicalrecord searches using the International Classification of Diseases 9(ICD-9) and Current Procedural Terminology (CPT) codes listed inSupplementary Material S1. Reviewers at each site confirmed thatthe procedure type of control women identified by searching medicalrecord codes matched that of case women. In-patient charts werereviewed for inclusion and exclusion criteria, and baseline patientcharacteristics, surgical data, and postoperative management infor-mation were collected.

Baseline characteristics included age, body mass index (BMI, calcu-lated as weight in kilograms divided by the square of height in meters),race, comorbidities classified by the validated Charlson comorbidityindex (CCI), prior abdominal surgery, prior bowel surgery, menopausalstatus, and smoking status. Comorbidities were classified on the basis ofthe CCI, where higher numbers indicated more severe comorbidities[11]. Surgical data included procedure type and indication; typeof incision; operative time; concomitant bowel surgery such as bowelresection, appendectomy, and enterotomy (indicated or incidental);anesthesia type; estimated blood loss; intraoperative complications;lysis of adhesions; use of adhesion barriers and hemostatic agents;and blood transfusion (intraoperative or postoperative). Postoperativemanagementwas reviewed including the diet ordered on postoperativeday 0 and pain management on postoperative day 0. For the analysis,the diet ordered immediately after surgery was categorized as eithernil per os or any type of diet.

Statistical analysis was performed via Stata/IC version 11 (StataCorp,College Station, TX, USA). Statistical comparisons were carried outbetween cases and matched controls by using conditional logistic re-gressions for binary outcomes and the Mantel-Haenszel test for con-tinuous or ordinal outcomes. Odds radios (ORs) with 95% confidenceintervals (CIs) and a P value of 0.05 or less were used to determine sta-tistical significance. Conditional multivariate logistic regressionmodels,adjusted for confounders such as age, were used to identify significantrisk factors.

3. Results

During the study period, 144 women met the inclusion criteriafor postoperative ileus/SBO following benign gynecologic surgery.The case women were matched to 288 controls, giving a total of 432patients. Eighty-five women (59%) developed ileus/SBO during theirindex hospitalization, 54 (38%) were readmitted for ileus/SBO aftertheir surgery, and 5 (3%) had ileus/SBO on their index admission andwere also readmitted for this diagnosis. Among the case patients,18 (13%) underwent reoperation for SBO. Most cases of ileus/SBO

occurred within the first week of surgery: the median number ofdays from initial surgery to the development of ileus/SBO was3 days. The median time to diagnosis was 2 days (range, 0–7 days) ifthe SBO/ileus was diagnosed during the index admission, and 8 days(range, 1–358 days) for patients who were readmitted.

The baseline characteristics of the study women are given in Table 1.In the univariate analysis, Hispanic women were less likely to developileus/SBO compared with white women, whereas post-menopausal sta-tus, prior abdominal surgery, and higher CCI scores were positively asso-ciated with ileus/SBO. Older age was also significant as a risk factor forileus/SBO (OR, 1.02; 95% CI, 1.00–1.04; P = 0.05). BMI, smoking status,and prior bowel surgerywere not significantly associatedwith ileus/SBO.

The procedure type and indication for procedure are given inTable 2. Among the casewomen, 104 (72%) procedureswere performedabdominally, 24 (17%) laparoscopically, 11 (8%) vaginally, and 5 (3%)robotically. On univariate analysis, adnexal mass as the indication forsurgerywas associatedwith ileus/SBO (OR, 2.6; 95% CI, 1.1–5.8), where-as all other indications were unrelated.

Intraoperative and postoperative factors are given in Table 3.Midline vertical incision was associated with ileus or SBO (OR, 2.1;95% CI, 1.3–3.6) when compared with all other incision types. Factorsconsistent with complicated or extensive surgery were associatedwith ileus or SBO: prolonged operative time (OR, 1.004; 95% CI,1.001–1.007; P = 0.03), concomitant bowel surgery (OR, 6.50; 95%CI, 2.12–19.94), lysis of adhesions (OR, 2.34; 95% CI, 1.48–3.69),intraoperative complications (OR, 2.48; 95% CI, 1.48–4.17), cystotomy(OR, 6.0; 95% CI, 1.21–29.73), enterotomy (OR, 9.0; 95% CI, 1.94–41.65),increased blood loss (OR 1.001; 95% CI, 1.0001–1.001; P = 0.02),intraoperative and/or postoperative blood transfusion (OR, 3.81;95% CI, 2.01–7.23), and use of hemostatic agents (OR, 2.34; 95% CI,1.16–4.75). For postoperative measures, having a regular diet on post-operative day 0 seemed to be protective for ileus/SBO. Once this rela-tionship was adjusted for the intraoperative complications, however,it did not remain significant.

Midline vertical incision, CCI scores, concomitant bowel surgery,lysis of adhesions, cystotomy, and blood transfusion were includedin the multivariate logistic regression analysis. Blood transfusionwas included in the model instead of estimated blood loss becauseof its clinical significance. After multivariate logistic analysis, factorsassociated with increased risk for ileus/SBOwere concomitant bowelsurgery (OR, 4.3; 95% CI, 1.18–15.78), cystotomy (OR, 8.7; 95% CI,

Table 2Procedure type and indication.a

Cases(n = 144)

Controls(n = 288)

OR (95% CI)b

Primary procedureTotal hysterectomy 61 (42) 127 (44)Supracervical hysterectomy 17 (12) 33 (12)Myomectomy 13 (9) 26 (9)Sacral colpopexy 16 (11) 29 (10)Vaginal colpopexy 4 (3) 7 (2)Ovarian cystectomy 2 (1) 4 (1)Salpingo-oophorectomy 21 (15) 46 (16)Salpingectomy/salpingostomy 4 (3) 8 (3)Other 6 (4) 8 (3)

Indication for procedureSymptomatic fibroids 45 (31) 110 (38) Ref.Cervical dysplasia 1 (1) 3 (1) 0.9 (0.8–8.8)Adnexal mass 38 (26) 64 (22) 2.6 (1.1–5.8)Prolapse 27 (19) 52 (18) 2.5 (0.3–18.7)Endometriosis 2 (1) 3 (1) 2.8 (0.3–23.4)Pelvic pain 6 (4) 11 (4) 2.1 (0.6–7.4)Endometrial hyperplasia 1 (1) 0 (0) –

Dysfunctional bleeding 12 (8) 26 (9) 1.3 (0.5–3.2)Tubo-ovarian abscess 3 (2) 3 (1) 4.8 (0.6–37.7)Ectopic pregnancy 3 (2) 8 (3) 1.4 (0.1–16.8)Other 6 (4) 8 (3) 4.1 (0.7–8.8)

Abbreviations: CI, confidence interval; OR, odds ratio.a Values are given as number (percentage) unless stated otherwise.b Odds ratio for univariate analysis.

110 D.D. Antosh et al. / International Journal of Gynecology and Obstetrics 122 (2013) 108–111

1.48–51.47), lysis of adhesions (OR 1.7; 95% CI, 1.03–2.83), and bloodtransfusion (OR, 2.9; 95% CI, 1.44–5.95). Midline vertical incisionand CCI score were no longer significant risk factors for ileus/SBO.Several multivariate models were analyzed to include other sig-nificant variables: age, postmenopausal status, and operative timewere no longer significant risk factors for ileus/SBO in these models(P > 0.05).

Table 3Operative and postoperative outcomes.a

Cases(n = 144)

Controls(n = 288)

OR (95% CI)b

Type of incisionPfannenstiel 50 (35) 126 (44) Ref.Midline vertical 55 (38) 77 (27) 1.80 (1.13–2.86)Maylard 2 (1) 0 (0) –

Cherney 0 (0) 0 (0) –

Laparoscopic 27 (18) 59 (21) 1.15 (0.84–1.58)Vaginal 10 (7) 23 (8) 1.14 (0.84–1.58)Infraumbilical 0 (0) 2 (1) –

Midline vertical vs all otherincision types

55 (38) 77 (27) 2.1 (1.3–3.6)

Operative time, min 156.5 ± 74 140.1 ± 82 1.004 (1.001–1.007)Concomitant bowel surgery 13 (9) 4 (1.4) 6.50 (2.12–19.94)Anesthesia

General 143 (99) 280 (98) Ref.Spinal/epidural 1 (1) 6 (2) 0.25 (0.03–2.44)

Intraoperative complications 39 (27) 37 (13) 2.48 (1.48–4.17)Cystotomy 6 (4) 2 (1) 6.0 (1.21–29.73)Enterotomy 9 (6) 2 (1) 9.0 (1.94–41.65)Hemorrhage 24 (17) 30 (10) 1.78 (0.97–3.22)

Concomitant adhesiolysis 68 (48) 85(30) 2.34 (1.48–3.69)Blood transfusion(intra- or postoperative)

34 (24) 26 (9) 3.81 (2.01–7.23)

Use of adhesion barrier 15 (11) 24 (8) 1.46 (0.66–3.26)Use of hemostatic agent 19 (13) 18 (6) 2.34 (1.16–4.75)EBL, mL 399 ± 599 293 ± 363 1.001 (1.000–1.001)

Abbreviations: CI, confidence interval; EBL, estimated blood loss; OR, odds ratio.a Values are given as mean ± SD or number (percentage) unless stated otherwise.b Odds ratio for univariate analysis.

4. Discussion

The present retrospective case–control study has identified severalrisk factors, such as concomitant bowel surgery, lysis of adhesions,cystotomy, and need for blood transfusion, that are potentially relatedto the complexity of surgery and are associated with the developmentof ileus/SBO. We hypothesized that patient characteristics such asage and medical comorbidities might be significantly associated withileus/SBO. Notably, however, age, postmenopausal status, and CCIscores did not remain significant risk factors after controlling for othervariables. Furthermore, we anticipated that longer surgical times andlarger blood loss would result in a higher incidence of ileus/SBO.Although operative time was not a risk factor in the present study,blood loss necessitating blood transfusion was found to be a significantrisk factor for ileus/SBO.

The present results increase knowledge of the development ofileus/SBO specific to gynecologic populations. Regarding baselinecharacteristics or preoperative risk factors for ileus/SBO, Whiteheadet al. [7] showed that older age is a risk factor for patients undergoingabdominal sacrocolpopexy. Age was not a risk factor in the presentstudy, perhaps owing to the younger age of the study women. Previ-ously identified risk factors for postoperative ileus following gastro-intestinal surgery include prolonged surgical time, increased bloodloss, and higher total opiate dose, whereas the strongest risk factorfor the development of postoperative SBO seems to be the presenceof intra-abdominal adhesions [9,12,13]. The present study also foundan association with concomitant adhesiolysis, indicating that thepresence of adhesions is probably a significant risk factor for the de-velopment of ileus/SBO. Although a strong association with estimatedblood loss was not found, there was an association with perioperativeblood transfusion. Owing to the multicenter design of the study, itwas not possible to determine opiate dose because of differences indata collection at each site and the large variety and combinationsof analgesics used. Although many surgeons place patients at risk forileus/SBO on nil per os status, the data did not show that womenwho were fed immediately after their surgery were more likely to de-velop ileus/SBO. The present study expands on previously reporteddata by including many types of gynecologic surgery and by investi-gating a more comprehensive list of intraoperative factors.

The strengths of the study include its multicenter nature, which in-corporated many surgeons with varying experience, different degreesof participation among trainees, differing levels of patient acuity, andvarious operative and postoperative management styles. Further-more, the large sample of benign gynecologic patients contrasts withprevious studies that have focused mainly on gastrointestinal andgeneral surgeries. On the basis of the results, it is not possible to pre-dict preoperatively which patients are at risk for ileus/SBO. For pa-tients with intraoperative complications such as cystotomy, bloodtransfusion, and concomitant bowel surgery, however, preventativemeasures should be considered in the immediate postoperativeperiod. Previous studies have shown that gum-chewing and use ofpharmacologic agents that limit the effect of narcotics and inflamma-tion of the bowel, such as alvimopam and ketorolac, may preventor decrease the risk of ileus [14–18]. Future prospective studies areneeded to determine whether these measures can be applied to thegeneral gynecologic patient population.

The main limitations of the study are related to the retrospectivestudy design. The analysis demonstrated an association betweenintraoperative risk factors and ileus/SBO, but not a causal relationship.Furthermore, the impact of other potentially significant factors such assurgeon experience was not evaluated in the study. Because cases andcontrols were matched by type of gynecologic surgery and route, itwas not possible to determine whether surgery type or route increasedthe risk of ileus/SBO; however, the cases of ileus/SBO comprised 72%abdominal, 17% laparoscopic, and 8% vaginal surgeries, suggesting thatminimally invasive procedures may have a lower risk of ileus/SBO.

111D.D. Antosh et al. / International Journal of Gynecology and Obstetrics 122 (2013) 108–111

Lastly, ileus and SBO were grouped together in the analysis becauseboth diagnoses have a similar clinical presentation and the initialmanagement is often the same; in addition, radiographic imaging isnot always performed and is not always able to differentiate betweenileus and partial SBO [19,20], as was true in the present patient popula-tion. Perhaps these diagnoses should not be grouped together owingto their different pathophysiologic mechanisms of disease (decreasedgastrointestinal motility vs obstruction). For those patients who re-quired reoperation, it is reasonable to assume that they had a truediagnosis of SBO. However, we were unable to analyze this subgroupfor risk factors owing to the small number of patients.

In conclusion, concomitant bowel surgery, lysis of adhesions, andperioperative complications such as cystotomy and blood transfusionwere risk factors for the development of ileus/SBO following benigngynecologic surgery. Although surgeons cannot control the difficultyor complexity of surgery, they can control management of the post-operative course. Identification of these intraoperative events shouldtrigger increased postoperative surveillance for ileus/SBO. In addition,future efforts and investigation into how to decrease postoperativeileus/SBO should focus on intraoperative interventions and postoper-ative management.

Supplementary data to this article can be found online at http://dx.doi.org/10.1016/j.ijgo.2013.03.014.

Acknowledgments

The study was supported and funded by the Fellows’ Pelvic Re-search Network (sponsored by the Society of Gynecologic Surgeons).Biostatistical support for this project has been funded, in part,with federal funds (grant #UL1RR031975) from the National Centerfor Research Resources, National Institutes of Health, through theClinical and Translational Science Awards Program (a trademark ofthe Department of Health and Human Services), which is part of theRoadmap Initiative “Re-Engineering the Clinical Research Enterprise.”

Conflict of interest

The authors have no conflicts of interest.

References

[1] Lubawski J, Saclarides T. Postoperative ileus: strategies for reduction. Ther ClinRisk Manag 2008;4(5):913–7.

[2] Luckey A, Livingston E, Taché Y. Mechanisms and treatment of postoperativeileus. Arch Surg 2003;138(2):206–14.

[3] Woods MS. Postoperative ileus: dogma versus data from bench to bedside. PerspectColon Rectal Surg 2000;12(2):57–76.

[4] Salvador CG, Sikirica M, Evans A, Pizzi L, Goldfarb N. Clinical and economic out-comes of prolonged postoperative ileus in patients undergoing hysterectomyand hemicolectomy. P&T 2005;30(10):590–5.

[5] Steed HL, Capstick V, Flood C, Schepansky A, Schulz J, Mayes DC. A randomizedcontrolled trial of early versus “traditional” postoperative oral intake after majorabdominal gynecologic surgery. Am J Obstet Gynecol 2002;186(5):861–5.

[6] Ridgeway B, Barber MD, Walters MD, Paraiso MF. Small bowel obstruction aftervaginal vault suspension: a series of three cases. Int Urogynecol J Pelvic FloorDysfunct 2007;18(10):1237–41.

[7] Whitehead WE, Bradley CS, Brown MB, Brubaker L, Gutman RE, Varner RE, et al.Gastrointestinal complications following abdominal sacrocolpopexy for advancedpelvic organ prolapse. Am J Obstet Gynecol 2007;197(1):78.e1–7.

[8] Isik-Akbay EF, Harmanli OH, Panganamamula UR, Akbay M, Gaughan J, ChatwaniAJ. Hysterectomy in obese women: a comparison of abdominal and vaginal routes.Obstet Gynecol 2004;104(4):710–4.

[9] Al-Took S, Platt R, Tulandi T. Adhesion-related small-bowel obstruction aftergynecologic operations. Am J Obstet Gynecol 1999;180(2 Pt 1):313–5.

[10] Lowenstein L, Olivera C, Harvie H, Schaffer J, Young S. The Fellows' Pelvic ResearchNetwork (FPRN). Int Urogynecol J Pelvic Floor Dysfunct 2008;19(7):895–7.

[11] Charlson ME, Pompei P, Ales KL, MacKenzie CR. A newmethod of classifying prog-nostic comorbidity in longitudinal studies: development and validation. J ChronicDis 1987;40(5):373–83.

[12] Artinyan A, Nunoo-Mensah JW, Balasubramaniam S, Gauderman J, Essani R,Gonzalez-Ruiz C, et al. Prolonged postoperative ileus-definition, risk factors, andpredictors after surgery. World J Surg 2008;32(7):1495–500.

[13] Stewart RM, PageCP, Brender J, SchwesingerW, EisenhutD. The incidence and risk ofearly postoperative small bowel obstruction. A cohort study. Am J Surg 1987;154(6):643–7.

[14] Fanning J, Valea FA. Perioperative bowel management for gynecologic surgery.Am J Obstet Gynecol 2011;205(4):309–14.

[15] Kehlet H. Postoperative ileus—an update on preventive techniques. Nat Clin PractGastroenterol Hepatol 2008;5(10):552–8.

[16] Büchler MW, Seiler CM, Monson JR, Flamant Y, Thompson-Fawcett MW, Byrne MM,et al. Clinical trial: alvimopan for the management of post-operative ileus after ab-dominal surgery: results of an international randomized, double-blind, multicentre,placebo-controlled clinical study. Aliment Pharmacol Ther 2008;28(3):312–25.

[17] Ludwig K, Viscusi ER, Wolff BG, Delaney CP, Senagore A, Techner L. Alvimopan forthe management of postoperative ileus after bowel resection: characterization ofclinical benefit by pooled responder analysis. World J Surg 2010;34(9):2185–90.

[18] Chen JY, Ko TL, Wen YR, Wu SC, Chou YH, Yien HW, et al. Opioid-sparing effects ofketorolac and its correlation with the recovery of postoperative bowel function incolorectal surgery patients: a prospective randomized double-blinded study. ClinJ Pain 2009;25(6):485–9.

[19] Sajja SB, ScheinM. Early postoperative small bowel obstruction. Br J Surg 2004;91(6):683–91.

[20] Heinberg EM, Finan MA, Chambers RB, Bazzett LB, Kline RC. Postoperative ileus ona gynecologic oncology service—do abdominal X-rays have a role? Gynecol Oncol2003;90(1):158–62.