Sx of the Rectum, anus and Perineum Flashcards
(94 cards)
1
Q
Describe the anatomy of the rectum
A
- Pelvic inlet → ventral to 2nd/3rd caudal vertebrae→ beginning of the anal canal
- Short segment retroperitoneal before it joins the anal canal
- Lacks serosa (healing)
- Dorsal to reproductive organs, bladder and urethra
2
Q
Blood suppky go rectum?
A
cranial rectal artery
3
Q
What are the 4 layers fo rectum?
A
mucosa, submucosa, muscularis, and serosa
4
Q
What is the mesorectum?
A
continuation fo mesocolon
5
Q
What are some indications for surgery of the recum ansu and perineum
A
- Rectal prolapse
- Stenosis/stricture
- Neoplasia
- Congenital abnormality
- Anal sac disease
- Anal Furunculosis/Perianal fistulae
- Rectal perforation
- Perineal hernia
- Diagnostic biopsy
6
Q
What is a differential for rectal prolapse?
A
LI intussuception
7
Q
Cause of rectal prolapse?
A
anything causing tenesmus
8
Q
Surgical maangement of rectal prolpase?
A
- Manual reduction & purse string suture (3-5 days) (tx of underlyign cause too)
- Colopexy; if recurrence despite tx the underlying cause
- Rectal amputation; if non-reducible/necrosis (cats high incidence of strictures forming)
9
Q
how to do a purse string method?
A
10
Q
Where does colorectal stenosis happen?
A
At the anorectal junction
11
Q
Colorectal stenosis can be one of two things:
A
- Acquired - secondary to chronic inflammation , trauma, anal furunculosis, colorectal tumour
(adenocarcinoma) or previous surgery - Congenital - atresia ani
12
Q
CLs of colorectal stenosis?
A
tenesmus, dyschezia, haematochezia or narrowed/flattened faeces, megacolon
13
Q
Diagnosis fo colorectal stenosis?
A
- Rectal examination
- Positive contrast recto-colonography
- Biopsy: to rule out tumour (adenocarcinoma)
14
Q
Tx of colorectal stenossis?
A
»Treatment; dilate manually under GA
* Balloon dilatation or bougiennage (more common) +/- tramincinnolone injections
* Stent or resection can be attempted
15
Q
Compare and contrast rectal neoplasia in dogs vs cats
A
16
Q
Clinical signs of rectal neoplasia?
A
tenesmus, dyschezia and haematochezia, weight loss, diarrhoea and vomiting
17
Q
Diagnosis & tx of rectal neoplasia?
A
Diagnosis; rectal palpation or colonoscopy + biopsy
Treatment; surgical resection with wide margins (often not possible)
➢risk stricture formation
18
Q
Describe benign adenomatous polyps as rectal neoplasia?
A
- Single/multiple, raised or prudnuculated
- Usually distal rectum or anorectal junction
19
Q
CS of Benign Adenomatous Polyps ?
A
haematochesia, tenesmus, abnormal faeces, dyschesia, and D+
20
Q
Who do we see these in?
A
MALEs & collies and WHWT predisp
Malignant transformation can occur
21
Q
How do we get rid of benign adenomatous polyps?
A
- Most easily prolapsed through anus for removal
- Full thickness excision is not usually necessary
- At least biopsy
22
Q
How do we remove cranial rectal masses?
A
caudal laparotomy and pelvic osteotomy
23
Q
How to we approach mid-distal rectal passes?
A
Rectal pull through/anal approach
24
Q
Post -op mass rmeoval?
A
give meloxicam (anti-neoplastic)
25
Is resection of rectal neoplasia currative?
* Resection curative for adenocarcinoma and leiomyosarcoma (slow to met)
* Local recurrence with incomplete resection
26
Survival after resection?
6m-2yrs
annular edenoC=> less than 2 months
Cats - longer survival if subtotal colectomy and chemo (if no mets 6-8m)
27
Why might we resect rectum?
* Masses – benign or neoplastic
* Polyps/neoplasia
* Traumatised or necrotic tissue
* Prolapse/fistula
* Strictured segments
28
What different approaches may we use?
Ventral
Dorsal
Rectal pull-through
Anal approach
29
What pre-op considerations for Rectum sx?
* Peri-op Abs
* Pain relief – opioids/epidural
* Do not perform pre op enema
- Can do up to 12 hours before
- Low residue diet 2-3 days prior to surgery
- Longer starve (24 hours)
* Manually evacuate bowel after anaesthesia
30
What max amount to resect of the rectum?
6 cm max
31
Describe the Ventral approach to the rectum?
* Access to cranial rectum and caudal colon/colorectal junction
* Caudal ventral laparotomy
32
Descrieb Dorsal approach to the rectum?
* Lesions in caudal or mid rectum but not anal canal
33
Describe rectal pull-through approach?
Distal colonic/midrectal not approachable by abdomen
* Too large for anal approach
* High risk of stricture
34
Describe the anal approach?
* Small, non invasive, pedunculated polyps which can be
exteriorised via anus
* Caudal rectum or anal canal
* Perforations
* Can resect annular lesions and anastomose
35
What complications of preianal and rectal sx?
* Infection
* Dehiscence
* Tenesmus
* Rectal prolapse
* Haematochezia
* Incontinence (temporary or permanent)
* Anal stricture
* Haemorrhage
* Recurrence/metastases
* Nerve damage (pudendal, sciatic, femoral)
36
Describe risk of faecal incontinence post-op?
* Removal of distal 1.5 cm of rectum (terminal rectal cuff) even if no damage to sphincter
* Greater than 4-6 cm rectum resected
* More than half of external anal sphincter damaged/resected
* Perineal nerve damage
37
Prognosis for benign rectal polyp?
Good
38
Some top tips for rectal sx?
* Use peri-(and post?) op antibiotics in this area
* Consider epidural and opioids for pain
* Rectal prolapse not uncommon
39
What are the three zones of the anus?
: columnar, intermediate, cutaneous (internal & external zone)
40
What is in each zone of the anus?
* Anal glands - columnar and intermediate zones
* Anal sacs - Internal zone of cutaneous zone and in between internal & eternal anal sphincter
* Internal anal sphincter – thickening of circular smooth muscle
* External anal sphincter – circumferential band of skeletal muscle
41
blood supply of the anus?
internal pudendal and perineal arteries
42
Innervation of the anus?
Pelvic plexus (pelvic and hypogastric nerves)
43
What major innervation to external sphincter?
pudendal nerve
44
What are some pre-anal sac sx considerations?
- Positioning
- Purse string suture
- Bowel prep -> reduce faecal flow during/after sx
- AMs: antibiotics peri- and post op (reduce intraluminal bact load)
45
What other consideration?
Faecal incontinence=> copious lavage before closure, absorbably monofilament & non-abs mnofil (SC & skin)
46
describe Atresia any
* Congenital
* +/- recto-vaginal or recto-urethral fistulae
47
Describe types of atresia ani?
* Type I: Congenital anal stenosis
* Type II: Persistence of anal membrane; rectum ends as blind pouch
* Type III: Imperforate anus with blind pouch at level of rectum
* Type IV: normal anus and distal rectum,
blind
* pouch at proximal rectum
48
How does Type 1 present?
t at weaning with tenesmus, constipation, perineal swelling
49
How do types 2-4 present?
; normal for 2-4 weeks and failure to thrive, anorexia, abdominal enlargement, absence of
* defecation
50
Tx for Atresia ani?
* Type 1; bouinage or resection
* Types 2-4; surgical repair
51
Prgnosis of atresia ani?
POOR, high morbidity and mortality, high complication rate
52
describe localising anal sacs
* Invaginations of inner cutaneous zone
* Between external and internal anal sphincter muscles
* Dog: opening at anocutaneous junction
* Cat: opening 0.25cm lateral to the anus
53
What kind of anal sac disease might we see?
- Impaction, sacculitis, abscess
54
CS of anal sac dx?
Clinical Signs; scooting, licking, biting tail base/perineum, pain on
* sitting/defecation, draining tracts
55
Tx for anal sac dx?
manual expression, cannulation and lavage, lance and drain abscesses, pain relief +/- antibiotics
=> for refractory cases - sacculectomy
56
What are the common perianal tumours?
* Adenoma (benign)
* Adenocarcinoma (malignant)
57
What two types fo glands do perianal tumours arise from?
- Anal sac apocrine gland neoplasms
- Perianal (circumanal) glands (hepatoid glands)
58
Can you get other skin tumours?
YES -> MCT, melanoma
59
Prevalence of anal sac gland adenoC?
2% of all tumours in dogs
60
What sign is seen with anal sac adenoC? what about metastases?
* 27-90% hypercalcaemia and hypophosphatemia
* Paraneoplastic (PTHrp)
* 50% -80% metastatic at diagnosis
61
How does anal sac adenoC spread?
* Sublumbar LNs>lungs>spleen>lumbar vertebrae
62
Differentials for this?
* Differential diagnosis: Primary Hyperparathyroidism
* This produces true PTH
63
T/F corticosteroids help reduce signs of hyperca?
true
64
When should we be performing rectals?
ANY older dog that is polydipsic
65
CLS of adenoC?
palpable mass (rectal exam) mass
effect (tenesmus, dychezia, swelling) or
hypercalcaemia (PU/PD, weakness, V+, anorexia constipation)
66
Diagnosis ?
FNA, biopsy
* Staging: rectal exam, haem/Ca2+ serology, thorax/abdo rads + US
67
Compare and contrast causes of hyperCa?
68
HOW TO TREAT ANAL SAC ADENOC?
wide surgical excision + radiation +/- chemotherapy
* stabilise hypercalcaemia prior to surgery
* large tumours with no mets can shrink with chemo prior to sx
* segmental resection of anal sphincter
* remove metastatic sublumbar/intrapelvic LNs
69
When would we need radio/chemo ?
if failure to acheive wide margins & high metastatic rate
70
Persistent hyperCa?
= failure to excise or mets
* Check levels regularly for recurrence
* Persistent hyperCa+ can result in renal failure - biochem
71
Survival /prognosis?
* Small and no mets = 3-4 years; large and not mets 2 years, mets 12-24 months ?
* Negative prognostic indicators; metastasis, larger tumour size and hypercalcaemia
72
How can we do an anal sacculectomy?
Closed vs open
73
What steps foto sacculectomy?
* Insert something into sac to aid identification
* Umbilical tape, gel, foley catheter, instrument/probe
* Dissect as close to sacs as possible; reduces damage to rectal artery, nerve and external anal sphincter
74
Complications of sacculctomy?
draining tracts if not fully excised, infection, incontinence, anal stricture, dehiscence,
tenesmus
75
What are common perianal (circumanal gland) neoplasia?
Adenoma -> PErianal (prepuce, scrotum, tail base vulval ... single or multiple +/- ulcerated
76
T/F circumanal glands under hormonal control?
* entire males +/- testicular tumour
* decrease in size after neutering
77
Dx of circumanal gland tumour?
signalment and location
* Adenocarcinomas can occur – BIOPSY
* [NOT hormone dependant – metastasize – need wide excision]
78
Tx for perianal (cirumanal gland) neop?
* Treatment; castration +/- surgical excision
* May regress after castration
* Will recur without castration
79
Describe what anal furunculosis/ anal fistulae are?
* Suppurative, deep, ulcerated tracts
* Begins sterile → contaminated with bacteria
* Aetiology is unknown (likely immune-mediated cause)
80
Who is predisposed to furunculosis?
GSH - >broad based tail wit low carriage
81
Dx?
clinical presentation +/- histopath
82
Tx for furunculosis?
- Surgical: significant complications and recurrence
- Medical: nor always 100% effective, costyl
83
Medical dx for furunculosis?
84
SX tx for furunculosis?
85
When. dowe see perineal hernias?
* Weakness of muscles of pelvic diaphragm
* Dilatation & deviation of rectum
* Caudal protrusion of organs
86
Who is predisposed to perineal hernia?
- Entire males
- Castration prevents recurrence
- Concurrent prostatic dx is common
Any condition causing straining may predispose
87
Anatomy of the perineal hernia?
-> Pelvic diaphragm contains: external and sphincter msucle, coccygeus, levator ani
-> Ischiorectal fossa -> potential space b/w diaphragm and skin
-> Internal pudendal vessels & nerves -> run along. the internal obutrator nerve
-> Caudal rectal nerve= sole motor supply to external anal sphincter
88
Where do we commonly see hernias?
between levator ani, coccygeus and external anal sphincter muscles
89
Clinical signs. foperineal hernia?
* Soft, fluctuant mass in perineal region - reducible
* Unilateral or bilateral
* Faecal tenesmus
* Rectal dilatation or deviation upon rectal exam
* Loss of the pelvic diaphragm on rectal exam => Hook finger around external anal sphincter muscle into ischiorectal fossa→Diagnostic
* Retroflexion of bladder into hernia -> dyuria)
90
What medical management of perineal hernia?
* High fibre diet, add moisture
* Stool softeners (Lactulose)
* Manual evacuation of faeces may be
necessary
* Success rates of surgery reasonable, little
justification for medical management
91
Surgical options for perineal hernia?
- Internal obutrator transposition
- Castrate
- Colopexty if marked rectal dilation / deviation
- Cystopexy if retroflexed bladder
92
What most common hernial contents?
* Rectal flexure
* Rectal sacculation
* Prostate
* Fluid
* Omentum
* Fat
* Bladder
93
How woudl we go about an internal obutrator transposition?
* Consider epidural analgesia
* Antibiotics
* Manually evacuate rectum and anal purse string suture
* Sternal recumbency with pelvic limbs hanging over the end of the table
* Incised from tail base to ischial tuberosity
94
What complications from perineal hernia?
-> Faecal tenesmus most common (may lead to rectal prolapse
-> Faecal incontinence (uncommon)
- Sciatic nerve injury when doing tenotomy of obutrator M
- Detrusor atony/urinary dysfunction if bladder retroflexion
- Damage to ureters
- Haemorrhage/infection
- Reccurence
