Rectal Tears and Rectal Prolapse

Question 1

Why do rectal tears most commonly occur in the dorsal aspect of the rectum?

Answer 1

bc that’s where the circular muscle layer becomes thinner,
& thus more prone to tearing

*usu. intraperitoneal*

Question 2

Why would we have peritonitis in a Grade 3 rectal tear?

Answer 2

because we only have the serosal layer,
so bacT translocation…

if we can absorb fluid thru the serosal layer,
we can also translocate bacT
→rxn of peritoneum just d/t .the viscinity
of all the bacT on feces itself

Question 3

Predisposing factors for rectal tears in horses…

Answer 3

Arabian & miniature horses

mares

>9yo

fractious, previous tears

Question 4

What is buscopan & why do you not want to give it before your PE?

Answer 4

It’s a parasympatholytic w.rapid onset, lasts 30-40min…
*decreases rectal pressure by 70%*

causes marked increase HR

Question 5

Classify the tear:

mucosa & submucosa are torn

Answer 5

Grade I

Question 6

Classify the tear:

only the muscular layer is torn

Answer 6

Grade II

usu. Incidental finding

Question 7

Classify the tear:

mucosa, submucosa, & muscular layers are torn…
only remaining layer is serosa…

Answer 7

Grade IIIa

Question 8

Classify the tear:

right at 12 o’clock {dorsal}
mesorectum is the only layer intact…

Answer 8

Grade IIIb

Question 9

What are the 2 major things we worry about with a Grade IV {complete} Tear, thru the entire wall of rectum?

Answer 9

1. Massive fecal contamination into peritoneal cavity
   {if its cranial to the peritoneal reflection}
2. High risk of evisceration of either small colon or small intestine
   thru that tear, then the anus

Question 10

Why do we not see endotoxemia generally in Grade II rectal tears?

Answer 10

Mucosal barrier is intact
it’s the only grade that doesn’t bleed

Question 11

What anesthetic combination do we want to use as a first aid measure to stop the straining?

Answer 11

Xylazine & Lidocaine Epidural
{0.2mg/kg of each}

Haning Drop Technique
make sure horse is standing square; go for S5/Ca1 or C1/Ca2
basically the most cranial spot where we can see mvmt where we are lifting the tail

Question 12

What does general conservative MGMT in rectal tears entail?

Answer 12

• Antibiotics & NSAIDs
• Fluid Replacement
• laxatives + low bulk diet {pellets, mashes, etc}
  
  • oral fluids + MgSO₄
• daily removal of feces from rectum
  {q.1-2 hours for ~5 days, then q.6 hours for ~9-21 days}

Question 13

When performing direct suture repair as surgical means for repair thru the anus {close to the anus…}, where can the external anal sphincter be incised?

Answer 13

Dorsal commissure

close in direction of less tension
{transversely}
Sub-serosal suture bites <1.5cm to avoid lumen reduction
SI, non-absorbable

Question 14

Most rectal tears happen 15-20cm cranial to the anus. What are 2 other approaches we might utilize if the tear is not accessible thru the anus?

Answer 14

1. Laparoscopy
   {hand-assisted per rectum}
2. Ventral midline celiotomy
   → if Grade IV w.evisceration
   {to assess blood supply}