Editing Hernia

An abnormal protrusion of an organ or tissue through a defect in its surrounding walls.

== Anatomy ==

* Most commonly involves the abdominal wall
* Occurs only at sites where the aponeurosis and fascia are not covered by striated muscle.
* Neck/orifice is located at the innermost musculo-aponeurotic layer
* Sac protrudes from the neck, and is lined by peritoneum
* No consistent relationship between the area of a hernia defect and size of sac

== Presentation ==

* Reducible - when the contents can be replaced within the surrounding musculature
* Strangulated - compromised blood supply to contents
** Occurs more often in large hernias with small orifices
** Can be either obstructed arterial flow or venous drainage or both
* Obstructed - occurs due to adhesions between the contents of the sac and peritoneal lining
* Richter hernia - a small portion of the antimesenteric wall of the intestine is trapped within the hernia, and strangulation can occur without obstruction



== '''Loss of domain''' ==

* Not well-defined - 'a hernia sac of great size that forms a secondary abdominal cavity'; 'large enough that primary fascial closure either cannot be achieved without additional reconstructive techniques or significant risk of complications due to raised abdominal pressure'
** >20-50% of abdominal contents residing outside the abdomen
** One definition from Tanaka et al: '''when hernia volume greater than >25% of abdominal compartment volume (excluding hernia)'''
* Pathophysiology
** Abdominal contents no longer reside in the abdominal cavity, and therefore cannot simply be placed back inside
** Natural rigidity of abdominal wall becomes compromised and musculature retracts
** Complications:
*** MSK problems
*** Ventilatory dysfunction - cause paradoxical respiratory abdominal movement - compromised respiratory function
*** GIT dysfunction - can result in bowel oedema, stasis of the splanchnic venous system, urinary retention, and constipation
*** Psychosocial issues
* Management
** Patient needs to understand how big of an undertaking this is going to be
** Optimise everything medically - see separate topic under 'ventral incisional hernia'
** May need additional techniques for closure - see 'ventral incisional hernia'
*** Usually benefits from Botox and component separation
** Watch post-op for intra-abdominal hypertension

== '''Classification of hernias''' ==

* '''Anatomical - European Hernia Working Group'''

* Complex vs simple
** Patient factors
** Anatomical factors


== '''Management principles''' ==

* Goals
** Fix the problem/restoration of function in line with patient expectations
** Minimise complications, pain, disability
** Cosmesis
** Durable repair with low recurrence rate
** Functional/dynamic abdominal wall
* Principles
** Optimise patient pre-op
** Restore anatomy and recreate linea alba
** Reinforce the repair when possible with wide mesh overlap
** Tension-free repair
* Contraindications to operation
** Medically/surgically unfit
** Absence of available tissue
** No benefit or improvement in QoL
** Risks outweigh benefits


== '''Hernia emergencies''' ==

=== '''Strangulation or bowel obstruction = urgent repair''' ===

** Ideally within 4-6 hours from onset of symptoms

=== '''Acutely incarcerated, but no signs of strangulation''' ===

** Offer urgent repair
** Can also attempt reduction, and if reducible, can follow up with surgeon in a few days to exclude reincarceration and arrange elective repair
** If fails reduction, can proceed to urgent surgery
** 'Taxis' - the rearrangement of tissues, that is, reduction of hernia, to avoid surgery
*** Contraindications: presence of strangulated bowel within the hernia (tachycardia, hypotension, peritonitis; erythema, hot and painful local skin; blood tests including WCC are unreliable)
**** Note that it's generally very unlikely that the hernia contains strangulated bowel if it's been reduced successfully
**** Obstruction but not strangulation is not necessarily a contraindication to reduction
*** >24 hours since onset of symptoms seems to be associated with higher likelihood of strangulation
**** If within 24 hours and no sign of strangulation, attempt reduction; if later, surgery and examination of sac should be preferenced
*** GPS (gentle, prepared, safe)
**** Gentle manipulation through external ring - avoid 'reduction en masse' where the herniated bowel and constricting ring are reduced together, providing a false sense of achievement
**** Prepared - consider procedural sedation/'''IV morphine + midaz /min bolus morphine until desired level of analgaesia achieved)'''
**** Safe - avoid attempting if concern for strangulation
*** Procedure
**** As much trendelenburg position as tolerated
**** Direct herniae will be easier to re-insert
**** Gentle pulling on edge of sac - will realign sac in direction of canal
**** Gently massage back into canal
**** Can take 5-10 min
**** If bowel is present, a satisfying gurgling sound is often heard on reduction
**** Need period of observation post-reduction to ensure pain resolved

*

[[Category:Abdo wall and retroperitoneum]]
[[Category:Intern education]]