Internal Hernia – a brief review of its clinical features and management

1. Internal Hernia – a brief review of its clinical features and management Surgical Grand Round 22nd Oct, 2011; UCH C C Chan; TMH

2. Hernia • Hernia: protrusion of part or whole of a viscus through an abnormal opening in the walls of its containing cavity (Bailey & Love’s 25th) • internal: herniation confined to peritoneal cavity • external: herniation through defect in wall of abdomen or pelvis

3. Internal Hernia • congenital or acquired • overall incidence < 1% (1) • 0.6 - 5.8% of small-bowel obstruction (SBO)(1) • incidence has been increasing (2) (1) Newsom BD, Kukora JS. Congenital and acquired internal hernias: unusual causes of small bowel obstruction. Am J Surg 1986; 152:279–284 (2) Higa KD, Ho T, Boone KB. Internal hernias after laparoscopic Roux-en-Y gastric bypass: Incidence, treatment and prevention. Obes Surg 2003;13(3):350–4

4. Clinical features • symptoms & signs usually indistinguishable from band obstruction • mortality could be 50% (1) • usually diagnosed intra-op • ddx: external hernia, adhesion, intussusception, gall stone ileus (1) Mock CJ, Mock HE Jr. Strangulated internal hernia associated with trauma: Arch Surg 1958; 77:881–886

5. Internal Hernia A = paraduodenal B = foramen of Winslow C = intersigmoid D = pericecal E = transmesenteric, transomental, and transmesocolic F = retroanastomotic g = falciform ligament h = supravesical and pelvic

6. Anatomic predisposition to transmesenteric hernia with biliary-enteric anastomosis a)antecolic Roux-en-Y loop b) retrocolic Roux-en-Y loop

7. Retroanastomotic Hernia after partially gastrectomy Retrocolic gastrojejunostomy Antecolic gastrojejunostomy

8. Internal hernia defects after bariatric surgery A = mesocolic B = Petersen’s C = mesomesenteric

9. Common symptoms • non-specific • asymptomatic • intermittent attacks of vague epigastric discomfort • colicky periumbilical pain • nausea, vomiting

10. Ever-changing severity • relates to duration and reducibility of hernia, presence or absence of incarceration and strangulation • may be altered by changes in posture

11. Imaging • plain X ray abdomen • USG abdomen • barium enhanced studies / enteroclysis • CT abdomen

12. Usual CT findings • crowded, distended bowel in abnormal location and arrangement • segmental dilatation and prolonged stasis within the herniated loops • stretched, displaced, crowded, and engorged mesenteric vessels • displacement of other bowel segments • (propensity to spontaneously reduce)

13. M/68 • Hx: CA splenic flexure, L hemicolectomy good recovery • readmitted Day 13 post-op for abdominal distension and pain

14. CT scan

15. Management • depends on stability of patient • history is important • know that it occurs, prevent it from happening • blood tests and imaging are adjunct only

16. Management • prompt surgical intervention: assessment of bowel viability, reduction and closure of all internal hernia defects • hernial ring should not be incised liberally • reduction of the hernia may be accomplished by enterostomy, followed by closure of the ring

17. F/44 • acute LUQ pain with vomiting BO dailyno UTI, gyn symptoms • afebrile vitals stableabdomen - LUQ tenderness, no mass

18. CXR - no free gasAXR - no dilated bowel • Hb: 8.2, L/RFT: normal

19. CT scan

20. laparotomy • small bowel herniated through a small defect in round ligatment • bowel loop reduced • viability confirmed • defect repaired • good post-op recovery

21. M/67 • RIIH with mesh repair done • generalized severe abdominal pain for 1 day • fever with tachycardia, BP stable tenderness & guarding at right side of abdomen • ANC:17 Hb, R/LFT, amylase: normalCXR: no free gas

22. Emergency laparotomy • herniation of a segment of terminal ileum into a defect in mesosigmoid with gangrenous changes • limited right hemicolectomy done • post-op ICU care and smooth recovery

23. TMH dataJuly 07’ to July 11’ • 17 internal hernia diagnosed and operated • female to male: 4(23.5%) to 13(76.5%) • age: 22 to 83, mean: 58.3 • previous surgery: 70.6%

24. Types of internal hernia • transmesenteric type: 10 (58.8%) hernia neck was congenital fibrous band: 3 (17.6%) paraduodenal: 1 (5.88%) intersigmoid: 1 (5.88%) round ligament: 1 (5.88%) retroanastomotic: 1 (5.88%)

25. Clinical features • non-specific • X-ray may not show I/O • all end up in surgery

27. pre-op CT: 6/17 (33.3%) • comparing CT group to non-CT group: • 0% vs 63.6% peritonitis • 17% vs 36% significant acidosis (p=0.58%)(*) • 16.7% vs 54.5% bowel resection (P=0.22)(*) • 16.7% vs 18.2% mortality (P=0.49)(*) *Fisher’s Exact Test

28. Lesson to learn • know it occurs • CT might be valuable if the patient is not in distress clinically, having no clues from baseline Ix and might be expected to operate on +ve imaging results • laparoscopic repair possible • B Palmar, R Palmar. Laparoscopic management of left paraduodenal hernia. J Minimal Access Surgery: 2010; 6:122-24

29. Thank You Special thanks to Dr C C Cheung for inspiration and guidance & Dr K K Li for data framework