Rectal Prolapse (and Obstructive Defecation)

DEFINITION

Full thickness prolapse of the rectum beyond the anus.
- ie not if just mucosa and not if inside anus

Obstructive defecation is the inability to pass a bowel motion due to pelvic floor abnormalities; functional or structural.

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EPIDEMIOLOGY

Rectal Prolapse
Chronic constipation and straining
6:1 F/M
Older
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AETIOLOGY

See below
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BIOLOGICAL BEHAVIOUR

Pathophysiology
: Rectal Prolapse

Unclear but strongly associated with:

Functional Association

Chronic constipation and straining

Anatomical
Associations:
Deep Pouch of Douglas
Redundant sigmoid colon.
Pelvic floor weakening
Internal and external anal floor weakening
Pudendal neuropathy
Lack of normal fixation to rectum

Difficult to know whether functional precedes anatomical or vice versa

Pathophysiology : Obstructive Defecation

Important to distinguish causes as treatment differs
Structural causes
-
include stricture, rectocoele or enterocoele.

Functional causes
- include paradoxic contraction of the puborectalis muscle.

Rectocoele
Bulging of rectum into vagina through weak rectovaginal septum.
- septum weakens with age and parturition
<2cm = typically asymptomatic, accepted as a normal finding.
May coexist with other prolapses, sigmoidocoele, enterocoele, intussusceptions, perineal descent.

Non-relaxing puborectalis
"Non-relaxing puborectalis syndrome"
Puborectalis sling usually contracted, causing angulation of rectum, assisting with continence.
- relaxes with action to defecate.
Muscle contracts further as bowel passes, increasing angle of rectum.
In this syndrome, the more the pt strains --> the less successful the evacuation


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MANIFESTATIONS

Rectal Prolapse

Complain of rectal tissue protruding from anus.
- initially only with Valsalva
- later with minimal or no straining
Occasionally rectal bleeding

Obstructive Defecation

Sensations of incomplete evacuation, excessive straining
Need for assistance to pass stool - laxatives, enemas, digital

History

Determine:
- symptom history
- stool history
- prolapse history (how much tissue, triggers)
- associated symptoms (urinary, incontinence / leak, straining)

If laxatives alone are required to pass stool, suggests colonic inertia.

If manual evacuation required, may suggests rectocoele

Examination

Patulous anus frequency seen with prolapse

DEABMIM

INVESTIGATIONS

1. DRE
- resting tone, sphincter deficits
- ask to contract then valsalva; asses puborectalis: significant if fails to relax with strain.

2. Anoscopy
- assess for haemorrhoids, strictures, ulcers
- watch prolapse on Valsalva

3. Colonoscopy
- rule out lesions, strictures

4. Manometry
- assess sphincter complex,
+ electrophysiology to assess puborectalis relaxation.

5. Defecography
- helps diagnose paradoxical puborectalis motion.
- note rectocoeles and intussusceptions common on this study; presence is not an indication.

7. USS
Can assess sphincter defects

8. Colonic transit studies
Diagnose colonic inertia.
Ingest markers, follow-up on D3,5,7 to follow transit
Important as if they have this, your operation will not be effective.
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MANAGEMENT

Rectal Prolapse

Conservative
Limited options.
- Fiber, laxatives - minimise straining.
- Biofeedback and pelvic floor exercises also possible.
However really only effective for mucosal prolapse and internal intussusception; rarely successful for full-thickness prolapse.

Operative
Many options have been proposed and abandoned due to high recurrence rates.
Generally have a perineal or abdominal approach
Bowel prep and antibiotics are routine.

Options:

Abdominal

1. Rectopexy
2. Rectopexy with mesh
- not shown in RCTs to be superior
3. Resection rectopexy

Divide or preserve lateral attachments?
Risk is of denervation of rectum / damage to parasympathetic nerves.
With division of lateral ligaments
- worse constipation (25%)
- better continence (~25%)
With preservation of the lateral ligaments
- better constipation (~25%)
- better continence (~25%)
Bottom line: worse recurrence rates if preserved but that outweighed by benefit of improved constipation

Laparoscopic or open?
No difference with regard to mortality, morbidity, constipation, incontinence or recurrence rate

Perineal
1. Delorme's procedure
2. Altmeier perineal proctosigmoidcolectomy.

Choosing the Right Option?
Abdominal procedures preferred in healthy patients who can tolerate the operation.
Rectal prolapse and no constipation

--> abdominal rectopexy, vicryl mesh, preservation of lateral attachments.
- ideally laparoscopic.
Perinenal approaches preferred for those with comorbidities who cannot tolerate GA and operation.
- higher recurrence.
- perineal proctosigmoidectomy in frail patients; lower mortality and morbidity and recurrence cf Delorme
Recent trend toward perineal approach in younger patients; less nerve risk.


Procedures: Description

Rectopexy
Patient lithotomy
Lower midline or Pfannensteil.
Peritoneum along rectum incised, allows access to presacral avascular plan.
Sharp dissection down to pelvic floor.
Lateral dissection taken down only to middle hemorrhoidal vessel, safely preserving pelvic nerves.
Anterior peritoneum preserved to free rectum
Rectum then pulled up and out of the pelvis.
Fixed to sacrum using 4-6 sutures into presacral fascia.
Negligible mortality and recurrence <3%, continence improves
- but effect on constipation not consistent.

Rectopexy with Mesh
As above, but fixation with mesh.
Prolene or vicryl mesh fine.
Either anterior (Ripstein repair) or posterior.
Preferred:
Wrap mesh posteriorly around sides of rectum and fix to presacral fascia in the midline.
Leaving anterior rectum to expand as necessary.
When resecting... be aware of infection risk with mesh.

Resection Rectopexy
Mobilize rectum as above
Resect redundant portion of sigmoid colon.
Do not mobilize splenic flexure; higher recurrence.
Return rectum to pelvis
Improvement in constipation is key benefit / rationale for this approach.

Delorme
Mucosal stripping of the rectum
General, regional or local anaesthetic.
Prolapse everted, local with adrenaline injected circumferentially just proximal to the dentate line.
Circumferential mucosal incision 1-1.5cm proximal to dentate line.
Mucosa dissected free circumferentially to apex of prolapse.
Circular muscle then plicated, then redundant mucosa excised.
Mucosal anastomosis.
Low mortality, morbidity high 0-50%, recurrence high 5-30%.
- lead point of prolapse may be above site of mucosal dissection.
image

Altmeier (Perineal Proctosigmoidectomy)
General, regional or local anesthesia.
Lithotomy, rectal prolapse everted.
Local w adrenaline and circumferential incision just above dentate, then deepened to full thickness.
Abdo cavity entered, division of mesentery and vessels from below, freeing up redundant sigmoid colon.
Colon divided, anastomosis via interrupted absorbable sutures.
Mortality low, morbidity 0-25%
image


Obstructive Defecation

Non-operative Therapy
High-fibre diet (25-35g/day, increased fluid intake)
Laxatives and enemas

Paradoxic puborectalis syndrome
Biofeedback conditioning treatment
- physiological function converted to auditory or visual cue for patient to learn from.
- anal plug electrode in anus; connected to biofeedback device.
- patient contracts sphincters, bears down.
- with instruction, movements can become more purposeful and effective.
--> Success rate highly variable 30-90%, not sustained and drops to about 25% over time.
Botox
- potent neurotoxin paralyses muscles by presynaptic inhibition of acetylcholine release.
- Injected into puborectalis, initial success perhaps 70%, drops to 33%
- Lasts three months
- Long-term efficacy may be similar to Biofeedback.

Operative Therapy
No role for surgery.
STARR proposed, to restore anatomy and function by excising redundant tissue.
Circular stapler; pt in lithotomy
- first anterior then posterior rectal wall bites.
Overall success 60-65%, but with better exclusion criteria, reported as high as 90%
- complicated by pain, bleeding, incontinence and recurrence.
Controversial / role unclear, may be acceptable in hands of knowledgeable surgeon.

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REFERENCES
Cameron 10th