Mechanical Bowel Preparation in Elective Colorectal Surgery Is it evidence based ? Dennis CK Ng PYNEH

Background Mortality of colorectal surgery is mainly due to sepsis Very high mortality (>20%) before the introduction of iv antibiotics and mechanical bowel preparation Glenn F, et al, Ann Surg 1966

Decrease the bacterial load Improving bowel handling Enable palpation of whole bowel Avoid mechanical disruption of anastomosis by well-formed stool Facilitate the on-table colonoscopy Precipitate intestinal obstruction Spillage of bowel content Electrolyte and osmolarity disturbance

Current Status Now, more than 99% of colorectal surgeons routinely employed mechanical bowel preparation Zmora O, et al, Am Surg 2003 In my hospital Low residual diet 3 days before Fluid diet 1 day before NaPO 4 the day before OT

Is it really necessary? Primary anastomosis may be safe in an unprepared bowel in obstructed colon (emergency operation) White CM, et al, Dis Colon Rectum 1985 Mealy K, et al, Br J Surg 1988 Dorudi S, et al, Ann R Coll Surg Engl 1990 Naraynsingh V, et al, Br J Surg 1999

Is it really necessary? Primary repair of the bowel in penetrating colonic injury is safe in unprepared bowel George SM, et al, Ann Surg 1989 Sasaki LS, et al, J Trauma 1995 Jacobson LE, et al, Am Surg 1997 Curran TJ, et al, Am J Surg 1999 Conrad JK, et al, Dis Colon Rectum 2000

Literature Search Randomized Controlled Trials and Meta- analysis from literature Keywords: Mechanical bowel preparation Elective colorectal surgery

Randomized Controlled Trial 9 RCTs available in literature From 1992 to are full papers, 3 are abstracts

YearFormatSizeMBP / no MBP Bowel Prep Brownson et al1992Abstract17986 / 93PEG Burke et al1994Full paper18682 / 87Sodium picosulfate Santos et al1994Full paper15772 / 77Mannitol, laxative, enema Fillmann et al1995Full paper6030 / 30Mannitol Miettinen et al2000Full paper / 129PEG Tabusso et al2002Full paper4724 / 23PEG, mannitol Zomera et al2003Full paper / 193PEG, enema Bucher et al2003Abstract9347 / 46PEG, phophonate Fa-Si-Oen et al2003AbstractN/A125 / 125PEG

Randomized Controlled Trial Advantage Level Ib evidence Homogeneity of the procedures Disadvantage Inadequate sample size (power of 80% need 950 patients) Impossible in a single center

YearAnastomostic Leakage Wound Infection PrepNo PrepPrepNo Prep Brownson et al19928/671/675/867/93 Burke et al19943/824/874/823/87 Santos et al19947/724/7717/729/77 Fillmann et al19952/301/30 2/30 Miettinen et al20005/1383/1295/1383/129 Tabusso et al20025/240/232/240/23 Zomera et al20037/1874/19312/18711/193 Bucher et al20034/471/464/471/46 Fa-Si-Oen et al20037/1256/1259/1257/125

Meta-analysis 4 meta-analysis available in literature Cameron Platell et al 1998, Disease of the Colon & Rectum Pascal Bucher et al 2004, Archieves of Surgery K Slim et al 2004, British Journal of Surgery Cochrane Database of Systematic Review 2004

Meta-analysis Advantage Level Ia evidence Can have adequate power because the patient numbers are larger Disadvantage Heterogeneity between studies Details of individual study is not enough Publication bias

Meta-analysisCameron Platell et al Pascal Bucher et al K Slim et al Cochrane Database of Systematic Review Year Brownson et al, 1992×××× Burke et al, 1994×××× Santos et al, 1994×××× Fillmann et al, 1995××× Miettinen et al, 2000××× Tabusso et al, 2002× Zomera et al, 2003××× Bucher et al, 2003×× Fa-Si-Oen et al, 2003××

Methods Search into literature (no restriction on year, language, format) Randomized controlled trials only Quality of studies are reviewed Original data from the author Meta-analysis performed using raw data

K Slim et al, 2004

Pascal Bucher et al, 2004

Cochrane Database of Systematic Review, 2004

Anastomostic leakage Wound infection Mortality Cameron Platell et al 1998 More in MBP group (p<0.114) More in MBP group (p<0.002) N/A Pascal Bucher et al 2004 More in MBP group (p=0.03) More in MBP group (p=0.15) More in MBP group (p=0.60) K Slim et al 2004 More in MBP group (p= 0.032) More in MBP group (p=0.175) More in MBP group (not significant) Cochrane Database of Systematic Review 2004 More in MBP group (p=0.003) More in MBP group (p=0.07) More in MBP group (not significant)

Results Significantly more anastomotic leakage in patients receiving mechanical bowel prep when compared with no prep Increased septic complications and mortalities in patients receiving mechanical bowel prep, but not statistically significant

Problems Mainly use PEG, effect of other form of bowel prep? Antibiotics and mechanical bowel prep introduced at the same time, how about bowel prep alone? The results are confined to the open surgery, role in lap surgery?

YearFormatSizeMBP / no MBP Bowel Prep Brownson et al1992Abstract17986 / 93PEG Burke et al1994Full paper18682 / 87Sodium picosulfate Santos et al1994Full paper15772 / 77Mannitol, laxative, enema Fillmann et al1995Full paper6030 / 30Mannitol Miettinen et al2000Full paper / 129PEG Tabusso et al2002Full paper4724 / 23PEG, mannitol Zomera et al2003Full paper / 193PEG, enema Bucher et al2003Abstract9347 / 46PEG, phophonate Fa-Si-Oen et al2003AbstractN/A125 / 125PEG

Problems Mainly use PEG, effect of other form of bowel prep? Antibiotics and mechanical bowel prep introduced at the same time, how about bowel prep alone? The results are confined to the open surgery, role in lap surgery?

Problems Mainly use PEG, effect of other form of bowel prep? Antibiotics and mechanical bowel prep introduced at the same time, how about bowel prep alone? The results are confined to the open surgery, role in lap surgery?

Conclusion No good evidence (level I or II) so far from literature showed mechanical bowel prep can reduce complications Actually, it may be more dangerous than no bowel prep in elective open colorectal surgery The applications of studies are limited by their power and methods

Current Consensus Before further powerful evidence from literature Routine use of bowel prep is still the common practice

Any changes we can made? ? NaPO 4 instead of PEG ? Selective bowel preparation Not in right hemicolectomy Not in endoscopically obstructed lesions Favor in lap surgery

Thank You