“Best Evidence” in AWR Understanding Level 1 & 2 Studies

1. “Best Evidence” in AWRUnderstanding Level 1 & 2 Studies A Park MD, FRCSC, FACS University of Maryland Baltimore,MD

2. Overview: • Getting on the same page- reviewing terms • What is the evidence in AWR? • Mesh versus suture repair? • Laparoscopic versus open? • Onlay/Inlay versus Underlay? • Transfacial fixation of mesh versus none ? • Mixing it up a bit • Take away

3. What is Evidence Based Medicine? • “Evidence-based medicine is the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients.” Centre for Evidence Based Medicine, www.cebm.net

4. Integration of EBM- CONSORT criteria EBM RTC Cohort Case-control Case series Expert opinion

5. A versus B designation • A – Meta-analyses • B – Individual studies

6. Incisional Hernia Repair (IHR) • Incisional Hernia is common (10-20 % of laparotomy incisions) • Morbidity (& mortality) still not insignificant • IHR associated with high rates of recurrence (estimates based on 10 year follow up) • Primary repair – 63% • Tension-free repair – 32% Mudge M, et al. Br J Surg 1985;72:70-71 Burger JW, et al. Ann Surg 2004;240:578-585.

7. Level 1B Evidence of Mesh vs. Suture Repair • 181 patients with primary hernia or first hernia recurrence randomized to suture or mesh repair • All hernias 6 cm or less • Up to 36 month follow-up (mean 26 months) Luijendijk et al. NEJM 2000 Aug 10;343(6):392-8.

8. Level 1B Evidence of Mesh vs. Suture Repair Luijendijk et al. NEJM 2000 Aug 10;343(6):392-8.

9. Level 1A Evidence Mesh vs. Suture repair • Data source • MEDLINE, EMBASE, LILACS, and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched from 1990 to 2007 • Study selection resulted in 7 RCTs • 1,141 patients • Data from three trials comparing mesh vs. suture repair pooled den Hartog, et al. Cochrane Database 2008, Issue 3, art. No. CD006438

10. Level 1A Evidence of Mesh versus Suture repair • Conclusion: • Tension free mesh repair is superior to primary repair for recurrence, inferior for infection Den Hartog, et al. Cochrane Database 2008, Issue 3, art. No. CD006438

11. Onlay/Inlay versus Underlay technique • Level 1A Evidence- den Hartog, et al. study again • Meta-analysis of 7 RCTs • 1,141 patients den Hartog, et al. Cochrane Database 2008, Issue 3, art. No. CD006438

12. Level 1A Evidence of Underlay vs. Overlay • Conclusion: • Insufficient evidence as to which type of mesh or which mesh position (on or sublay) should be used. den Hartog, et al. Cochrane Database 2008, Issue 3, art. No. CD006438

13. (Newer) Level 2B Evidence • Multicenter (VA) retrospective cohort study • 1,346 patients • Elective IHR at 16 VA hospitals • 31% primary closure, 30% open onlay, 30% open underlay, 9% laparoscopic • 6 year follow up Hawn M, et al. J Am Coll Surg 2010;210:648-657.

14. Level 2B Evidence Hawn M, et al. J Am Coll Surg 2010;210:648-657.

15. (Newer) Level 2B Evidence • Conclusions: Underlay technique – open or laparoscopic – decreases recurrence without increasing risk of infection Hawn M, et al. J Am Coll Surg 2010;210:648-657.

16. (Arch Surg 2002) • 8 studies (1 randomized, 7 cohort) • All paired studies • 712 patients (322 LVHR; 390 OVHR) • No gender preponderance • 2 studies with > previous repairs in LVHR group

17. Complications X • LVHR 14% vs 27% • LVHR Total complication 58% less likely From: Goodney PP et al. Arch Surg 2002;137:1161-5

18. Conclusions • LVHR offers: • < Total Complications • < LOS • = OR time

19. Open versus Laparoscopic Repair • Level 1A Evidence - Forbes SS, et al. • Data source- MEDLINE, EMBASE, CENTRAL, meeting abstracts between January 1950 and January 2009 • Study selection- Meta-analysis of 8(from 237 citations &13 studies)RCTs → 526 patients Forbes SS, et al. Br J of Surg 2009;96:851-8.

20. Open versus Laparoscopic Repair • Data Extraction – intention to treat study design, technique described, mesh AND defect size • Outcomes: hernia recurrence, duration of surgery, LOS, time until return to work, complications Forbes SS, et al. Br J of Surg 2009;96:851-8.

21. Level 1A Evidence of Open v. Lap • Conclusion: laparoscopic repair is at least effective, if not superior to, open tension-free repair • Shorter hospital stay • Fewer wound infections • Trends: • fewer hemorrhagic complications • fewer infections requiring mesh removal • NO difference in recurrence rates Forbes SS et al. Br J Surg 2009;96:851-858.

22. Laparoscopic vs open repair of incisional/ventral hernia: a meta-analysis(Sajid MS,Bokhari S et al Am J Surg 2009) • All studies on lap & open I/VHR 1993-2007 • 5 studies (from 1044 citations ,10 trials) met inclusion criteria- 366 pts • Targeted outcomes- OR time • - LOS • - complications & pain • -recurrences

23. Causes of “Heterogeneity” • Methodologic: • Different techniques of randomization • No allocation concealment in all trials • Not all analyzed on “intent to treat” • Different incl & excl criteria • Sample size calculation varied (never met!)

24. Causes of “Heterogeneity” • Clinical: • Technical variables- # and pos’n of ports • - mesh type (even PP),placement and fixation (some vs no transfascial) • - surgeon & institutional experience • - hernia size • Mix of primary/recurrent…variable f/u • Different outcome variables assessed

25. Conclusions (Sajid et al) • Laparoscopic Repair of I/VH (vs open): • Shorter LOS • Fewer periop complications • Shorter OR time • Recurrence rates and post op pain not significantly different

26. Suture fixation vs. tacks alone • Meta-analysis of prospective AND retrosepctive studies- between Level 1 and 2A • 35 studies • 545 patients had no sutures • 10 recurrences (1.8%) LeBlanc KA. Surg Endosc 2007;21:508-13.

27. Suture fixation vs. tacks alone LeBlanc KA. Surg Endosc 2007;21:508-13.

28. Suture fixation vs. tacks alone • Highly variable use of sutures • Technique NOT standardized • Overlap 2.5-5cm • Spacing 5cm? • Extremely difficult to draw meaningful conclusion LeBlanc KA. Surg Endosc 2007;21:508-13.

29. Laparoscopic and open incisional hernia repair: a comparison study A Park MD D Birch MD P Lovrics MD (Central Surgical 1996)

30. Patient Characteristics • No. of Patients • Sex (M/F) • Mean (range) age in yr • Mean (range) ASA score • Incisional hernia data • Lateral • Central/Midline • Upper abdomen • Lower abdomen • First repair • Previous repair • Laparoscopic • 56 • 30/26 • 58.8 (25-84) • 2.1 (1-3) • 8 • 33 • 9 • 5 • 40 • 16 • Open • 49 • 23/26 • 58.5 (35-82) • 2.2 (1-3) • 14 • 32 • 22 • 9 • 40 • 9 • p • NS • NS • NS • NS • NS • NS • NS

31. Laparoscopic Ventral Hernia Repair: Experience over 9 years and 850 cases B. Todd Heniford MD A. Park MD Bruce J. Ramshaw MD Guy R. Voeller MD (American Surgical Assoc’n 2003)

32. Study Background • Evaluate efficacy of LVH repair. • Prospective, consecutive series. • 4 Surgeons • Consistent technique & perioperative regimen. • Standardized F/U protocol: 2-4 weeks, 3mos, 6mos, yearly.

33. Summary of EBM • EBM is based on Levels characterizing the strength of evidence • Dependent on high quality smaller studies • Subject to statistical influence • “Study of studies”(armchair q’backing?) • Original studies –heavier lifting, must be done • DME & methodologists need to step up…

34. Summary of AWR • Mesh reduces recurrences • Laparoscopy at least as good as open – better for LOS and infection • Data suggests underlay technique reduces recurrences