Perianal surgery Flashcards
key anatomy of rectum?
extends from the inferior end of the sigmoid colon along the anterior surface of the sacrum to levator ani muscle
12cm
key anatomy of anal canal?
4 cm
levator ani muscle to anal verge
upper 2/3 of canal: lined by columnar epithelium, insensate
lower 1/3 of canal: squamous epithelium, sensate
dentate late = squamomucosal junction
white line = where anal canal becomes true skin
differences between upper 2/3 of anal canal and lower 1/3?
upper 2/3:
lined by columnar epithelium
insensate
superior rectal artery and vein
internal iliac nodes
lower 1/3:
squamous epithelium
sensate
middle and inf rectal artery and veins
superficial inguinal nodes
what is the dentate line?
squamomucosal junction of the anal canal
internal vs external anal sphincters?
internal:
thickening of rectal Smooth muscle -> involuntary control
External:
three rings of skeletal muscle (deep, superficial, subcut) -> voluntary control
what is the anorectal ring?
deep segment of external sphincter which is continuous w puboretalis muscle (part of levator ani)
demarcates junction between anal canal and rectum
palpable on PR 5 cm from anus
must be preserved to maintain continence
what is a perianal haematoma?
subcut bleeding from a burst venule caused by straining/ passage of hard stool
aka external pile (misnomer)
presentation of perianal haematoma?
tender blue lump at anal margin
pain worsened by defecation or movement
mx of perianal haematoma?
analgesia + spontaneous resolution
or
evacuation under LA
what is proctalgia fugax?
anal pain w no specific cause
usually young, anxious men
crampy anorectal pain, worse at night
unrelated to defecation
assoc w trigeminal neuralgia
what is proctalgia fugax assoc w?
trigeminal neuralgia
mx of proctalgia fugax?
reassurance
GTN cream
perineal warts assoc w?
MSM
may be due to HPV
or Syphilis (condylomata lata)
mx of perineal warts due to syphilis?
penicillin
mx of perineal warts due to HPV?
podophyllin pain
cryo
surgical excision
definition of haemorrhoids?
Dilated (enlarged) veins in the walls of the anus
(dilated and disrupted anal cushions)
where are haemorrhoids usually positioned?
3, 7 and 11 o clock
(due to this being where the 3 major arteries that feed the vascular plexuses enter the anal canal)
pathophysiology of haemorrhoids?
gravity, straining -> engorgement and enlargement of anal cushions
cushions protrude, may be damaged by hard stool-> bright red bleeding
haemorrhoids arise above dentate line -> not painful
may be gripped by anal sphincter -> thrombosis
(strangulated piles are acutely painful, may ulcerate or infarct)
causes of haemorrhoids?
constipation w prolonged straining
venous congestion: pregnancy, abdo tumour, portal HTN
classification of haemorrhoids?
1st degree: never prolapse
2nd: prolapse on defecation but spontaneously reduce
3rd: prolapse on defecation but require digital reduction
4th: remain permanently prolapsed
features of haemorrhoids?
fresh painless PR bleed
pruritus ani
lump in perianal area
severe pain = thrombosis
mx of haemorrhoids?
conservative:
increase fibre and fluid intake
reduce straining
medical:
topical analgesics, hydrocortisone
laxatives: lactulose, fybogel
interventional:
Banding, cryotherapy, infra red coagulation, injection w sclerosant
Surgical: haemorrhoidectomy
mx of thrombosed haemorrhoids?
analgesia
ice packs
stool softeners
bed rest w elevated foot of bed
pain usually resolves in 2-3 wks
haemorrhoidectomy usually not necessary
definition of anal fissure?
tear of squamous epithelial lining in lower anal canal
causes of anal fissure?
constipation
crohns
anal ca
herpes
features of anal fissure?
intense anal pain esp on defecation
fresh rectal bleeding (on paper)
examination of anal fissure?
PR often impossible
midline ulcer is seen
may have mucosal tag - sentinel pile
groin LNs suggest complicating factor e.g. HIV
mx of anal fissures?
if fissure recurrent, chronic or difficult to tx, pt needs examination under anaesthesia
conservative:
soaks in warm bath, toileting advice, dietary advice
medical:
laxatives, topical analgesia (Lignocaine, GTN, diltiazem), botulinum injection
surgical: lateral partial sphincterotomy
division of int anal sphincter @ 3 o clock
pre-op anorectal US and mannometry
definition of fistula?
abnormal connection between 2 epithelial surfaces
definition of fistula in ano?
abnormal connection between anorectal canal and the skin
risk factors for anal fistula?
perianal abscess
crohns
diverticular disease
rectal ca
immunosuppression
classification of fistula in ano?
high: cross sphincter muscles above dentate line
low: dont cross sphincter muscles above dentate line
presentation of anal fistula?
persistent anal discharge
perianal pain or discomfort
ix of anal fistula?
MRI
endoanal US
mx of anal fistula?
extent of fistula must be first delineated by probing fistula @ EUA
Low fistula:
fistulotomy and excision
- laid open to heal by secondary intention
high fistula:
fistulotomy could damage anorectal ring
suture (a Seton) passed through fistula and gradually tightened over months -> stimulates fibrosis of tract + scar tissue holds sphincter tgt
mx of perianal abscess?
abx
most require EUA w Incision and drainage
- wound packed, healing by secondary intention
look for anal fistula which complicates 30% of abscesses
examination findings of perianal abscess?
septic signs: fever, tachycardia
fluctuant mass on PR
perianal mass or cellulitic area
presentation of perianal abscess?
throbbing perianal pain
worse on sitting
occasionally a purulent anal discharge
definition of pilonidal sinus?
pilonidal: ‘nest of hair’
sinus: blind ending tract, lined by epithelial or granulation tissue, which opens into an epithelial surface
pathophysiology of pilonidal sinus?
hair works its way beneath skin -> foreign body reaction
-> formation of abscess
usually occur in natal cleft
risk factors of pilonidal sinus?
Males
often overweight w poor personal hygiene
occupations w lots of sitting e.g. truck drivers
presentation of pilonidal sinus?
recurrent pain
persistent discharge of purulent or clear fluid
abscesses
mx of pilonidal sinus?
conservative:
hygiene advice, shave/ remove hair from affected area
surgical:
incision and drainage of abscesses
elective sinus excision
most common type of anal ca?
80% SCCs
spread of anal ca to which lymph nodes?
above dentate line -> int iliac nodes
below detate line -> inguinal nodes
risk factors of anal ca?
HPV 16, 18, 31, 33
(increased incidence in MSM/ perianal warts)
features of anal ca?
perianal pain and bleeding
pruritus ani
faecal incontinence (70% have sphincter involvement @ presentation)
may -> rectovaginal fistula
Ix of anal ca?
low Hb (ACD)
endoanal US
rectal EUA + biopsy
CT/MRI: assess pelvic spread
mx of anal ca?
Chemoradiotherapy
Surgery:
- tumours that fail to respond to radiotx
- GI obstruction
- small anal margin tumours (good prognosis) w/o sphincter involvement
defintion of rectal prolapse?
protrusion of rectal tissue through the anal canal
classification of rectal prolapse?
type 1: mucosal prolapse
- partial prolapse
- commoner in childern esp w CF
- essentially large piles -> same mx
type 2: full thickness prolapse
- more common
- usually elderly females w poor O&G hx
Examination findings of anal prolapse?
visible prolapse
+/- excoriation and ulceration
decreased sphincter tone on PR
assoc uterovaginal prolapse
ix of anal prolapse?
sigmoidoscopy to exclude proximal lesions
anal manometry
endoanal US
MRI
mx of partial anal prolapse
phenol injection
rubber band ligation
surgery: delormes procedure
mx of complete anal prolapse?
conservative:
pelvic floor exercises, stool softeners
surgery:
Abdo approach - Rectopexy
(mobilised rectum fixed to sacrum w mesh)
perineal approach - Delorme’s procedure
(resect mucosa and suture the two mucosal boundaries)
