1. Surgical Grand Round 22nd Oct, 2011; UCH C C Chan; TMH
Internal Hernia – a brief review of its clinical features and management
Surgical Grand Round
22nd Oct, 2011; UCH
C C Chan; TMH
Good morning dear seniors, mentors and fellow colleagues. I am C C Chan from Tuen Mun hospital. Thank you very much for coming for I can learn from you by means of my presentation today. My topic is Internal Hernia – a brief review of its clinical features and management

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
Within the hernia family, there are namely internal and external type, to differentiate whether herniation is confined within peritoneal cavity or through a defect in abdominal or pelvic wall.

3. Internal Hernia congenital or acquired overall incidence < 1% (1)
% 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
Its cause can be congenital, for example, due to gut malrotation and mesenteric adhesion problem or acquired after surgery or trauma. The incidence used to be small back in the 80s’ and contribute to a small number of small-bowel obstruction, but it has been increasing because of more frequent liver transplantations and bariatric surgeries which contribute a lot to the iatrogenic part of it.

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
It has signs and symptoms similar to that of band obstruction and quite a high mortality especially when complicated with volvulus, usually it is diagnosed intra-operatively and the differential is of course that of external hernia

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
The nomenclature of each type internal hernia is determined by location of hernial ring, not by eventual position of the sac or the content. The first two types are of congenital and the 7th is of course acquired while the rest can be either congenital or acquired

6. Anatomic predisposition to transmesenteric hernia with biliary-enteric anastomosis
a) antecolic Roux-en-Y loop
b) retrocolic Roux-en-Y loop
Some of the acquired internal hernia, for example, transmesenteric hernia is most often caused by previous surgical procedure so that small bowel loops through defect in transverse mesocolon

7. Retroanastomotic Hernia after partially gastrectomy
Retrocolic gastrojejunostomy
Antecolic gastrojejunostomy
Whereas retroanastomotic hernia occurs when small bowel loops herniate posteriorly through a defect related to a surgical anastomosis. Less commonly, a very long afferent limb, ileum, cecum, or omentum can herniate into the retroanastomotic space. If antecolic surgery is performed, the afferent loop will bethe most commonly involved segment.

8. Internal hernia defects after bariatric surgery
A = mesocolic
B = Petersen’s
C = mesomesenteric
Internal hernia caused by the Roux limb can also occur after bariatric surgery as illustrated
mesocolic (small bowel herniation at the site where the Roux limb courses through the transverse mesocolon) and mesomesenteric (small bowel herniation through a mesenteric defect at the jejunojejunostomy)
A Petersen hernia may occur behind the Roux limb, but this is quite rare because surgeons are careful to close this defect at the time of surgery

9. Common symptoms non-specific asymptomatic
intermittent attacks of vague epigastric discomfort
colicky periumbilical pain
nausea, vomiting
Patients can be asymptomatic or complaining of intermittent epigastric pain or periumbilical colic, they can also complain of nausea and vomiting especially after an intake of a large meal

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
The severity of symptoms depends on duration of bowel obstruction cause by the hernia, the hernia reducibility and whether there is any complication, sometimes patient may find it slightly comfortable by changing the posture

11. Imaging plain X ray abdomen USG abdomen
barium enhanced studies / enteroclysis
CT abdomen
Most of the time, plain X-ray is not enough, other imaging modalities might not be easily available especially after office hour and the yield is not as good as CT

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)
Usual CT findings include apparent encapsulation of distended bowel loops in an abnormal location, evidence of intestinal obstruction and blood vessels displacement and engorgement, and displacement of bowel loops by herniated bowel
Due to the propensity of these hernias to spontaneously reduce, patients are best imaged when they are symptomatic

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 daily no UTI, gyn symptoms
afebrile
vitals stable abdomen - LUQ tenderness, no mass

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

19. CT scan
Grossly dilated small bowel is noted down to left adnexal region. The constant segment of dilated bowel loop is closely adjacent to the uterus and situates just caudal to the surgical clip for tubal ligation. Dilated bowel loop is grossly collapsed.

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: normal CXR: 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 data July 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%
-(1)17 cases of internal hernia were operated, around 72% were men, aged from 22 to 83 with mean age 58
-(2)71% had previous surgery including colectomy, gastrectomy, lap and open gynaecological surgeries

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%)
among them, the most common type was the transmesenteric hernia, followed by hernia through congenital fibrous band, unexpectedly, paraduodenal hernia accounts for one only.

25. Clinical features non-specific X-ray may not show I/O
all end up in surgery
The symptoms are non-specific as nearly all of them had either abdominal pain or distension and or vomiting or both
Patient could exhibit signs of shock and metabolic acidosis in severe cases
Some may not have typical signs of intestinal obstruction in X-ray films

26. All patient had either abdominal pain or vomiting or even both
Hx of Abd surgery
Abd pain/ distension
Vomiting
XR I/O
peritonitis
significant
acidosis
CT before OT
Type of internal hernia
Ischemia/
Perforation
Bowel resection
30 day post-op mortality 1
Congenital fibrous band
Intersigmoid
Transmesenteric
n/a
Round ligament
Retroanastomotic
Paraduodenal
All patient had either abdominal pain or vomiting or even both
Around 60% of patients had signs of intestinal obstruction in their x-ray films.
In those patients without CT scan done, ~64% of them had either peritonitis or significant acidosis or both
More than 80% of patients with CT scan had no clues from X-ray, significant peritoneal signs or biochemical abnormalities

27. comparing CT group to non-CT group: 0% vs 63.6% peritonitis
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