Ch. 94: Rectum, Anus, Perineum

Question 1

Skorupski JAVMA 2018

Outcome and clinical, pathological, and IHC factors associated with prognosis for dogs with early-stage AGASACA tx with surgery alone: 34 cases (2002-2013)

Overall MST?
Local recurrence %? Median time to recur?
% with mets?
What was associated with development of mets?
Margins associated with survival y/n?

Answer 1

MST 1237 d;

21% (7/34) dogs had local recurrence & median time to recurrence 354 d

26% (9/34) developed mets to LNs

Cellular pleomorphism positively associated with development of mets

Margins not significantly associated with survival

Question 2

Amsellem JAVMA 2019 PQ

Apocrine gland anal sac adenocarcinoma in cats: 30 cases (1994-2015)

Most common CS?
RF for local recurrence?
RF for death?
MST? 1 year survival rate?
11% cats had what?

Answer 2

Perineal ulceration / discharge most common CS;

Incomplete tumor margins & high nuclear pleomorphic score risk factors for local recurrence (37% local recur)

Local recurrence and high nuclear pleomorphic score risk factors for death

MST 260 d; 1 yr survival 42%

11% cats were hypercalcemic on presentation

Question 3

Elliot JAVMA 2019

Response and outcome following toceranib phosphate treatment for stage four anal sac apocrine gland adenocarcinoma in dogs: 15 cases (2013-2017)

Did dogs have measurable tumor reduction? Was it considered partial response?
Toceranib alone appropriate yes/no?

Answer 3

13 dogs had measurable tumor reduction volume (but not enough to say “partial response”)

Toceranib alone may not be appropriate for dogs w/ marked CS from the tumor, especially when limiting quality of life

Question 4

Schlag JSAP 2020

Comparison of methods to determine primary tumor size in canine AGASACA

Level of agreement between CT vs histopath vs digital rectal palpation re: tumor size?

What was most significant to present with metastatic disease?

Answer 4

Moderate agreement between maximal dimension of primary measured by CT vs formalin-fixed tissue and digital palpation

Dogs with tumors > 2.5 cm (tumor-stage 2) significantly more likely to present with metastatic disease

Question 5

Sutton JSAP 2022

Computed tomographic staging of dogs with anal sac adenocarcinoma

Association between anal sac mass size and LN enlargement?

Prevalence % of LN mets (“enlarged LN”)?

Pulmonary mets what %?

Answer 5

No association between anal sac mass size and presence/absence of lymph node enlargement

Prevalence of local metastatic disease 71% (based on enlargement alone, not FNA)

Pulmonary metastases 11% of cases - all had concurrent LN enlargement

Question 6

Swan VRU 2021

Pilot study evaluating the feasibility of stereotactic body radiation therapy for canine anal sac adenocarcinomas

Acute side effects - what and in how many?

What were late effects?

Answer 6

All patients developed acute effects - mild colitis, alopecia, and erythema.

Late effects - alopecia, variable dermal pigmentation and leuko- or melanotrichia within radiation fields, and rectal stricture in one patient.

Question 7

Williams VRU 2022

Minimal late radiation toxicity and transient early toxicity following postoperative definitive intent conformal radiation therapy (20 x 2.5 Gy) for canine apocrine gland anal sac adenocarcinoma

What % development of early toxicity & what signs most common?

MST?

Answer 7

Transient grade 3 dermatitis and anusitis developed in all dogs (100%), with resolution within 4 weeks.

MST 771 d

Question 8

Chen JAVMA 2022

Minimal complications observed with a modified surgical approach for treatment of canine anal sac neoplasia

Complications - rate intra-op? Post-op?

Answer 8

(12 dogs, retrospective)

No intraoperative complications (0%)

1/12 (8%) minor postop complication (paraparesis)

Question 9

Jimeno Sandoval JSAP 2022

Outcomes and complications of anal sacculectomy for non-neoplastic anal sac disease in cats: 8 cases (2006-2019)

What dx in all cases?

What % minor complications?

What % permanent fecal incontinent?

Answer 9

Dx: Anal sacculitis in all cases

4/8 developed minor and self-limiting complications (50%) (defecatory complications in 3/4)

0% permanent fecal incontinence

Question 10

Heng VRU 2021

Anal sacculiths may be an incidental finding in dogs

Prevalence %?
How many were bilateral?

Answer 10

Prevalence 7.5%

50% bilateral involvement

Equal distribution b/w right and left in unilateral cases

Question 11

Bernarde JSAP 2018 PQ

Surgical findings and clinical outcome after bilateral repair of apparently unilateral perineal hernias in dogs

txs they got?
% short-term post-op complications? What were they?
% middle-term post-op comp?
% dogs resolved of clinical signs at long term f/u?
Recurrence rate?
conclusions re: unilateral vs bilateral PH & re: recurrence with this tx plan?

Answer 11

tx: treated for apparently unilateral perineal hernia with bilateral herniorrhaphy, castration, colopexy, vas deferens pexy with or without cystopexy in single-stage procedures.

Short-term postop complications – 29% - all related to urinary issues; stranguria with urine retention, UTI, int hematuria (all recovered while in hospital)

Middle-term postop complications – 20%, 6/31 - 4 defecation related, 1 micturition / wound

93% dogs free of clinical signs related to hernia at long-term follow up;

recurrence rate 0%

–> perineal hernia in dogs might be considered a bilateral disease, even when the presentation is of apparently unilateral signs.
–> Recurrence is rare following bilateral herniorrhaphy combined with colopexy and deferens pexy with or without cystopexy.

Question 12

Bitton VSURG 2020

Use of bilateral superficial gluteal muscle flaps for the repair of ventral perineal hernia in dogs: a cadaveric study and short case series

Branches of what artery supplied fap?

Recurrence rate in the 3 dogs treated?

Answer 12

Branches of the caudal gluteal artery

0% recurrence in 6-12 months

Question 13

Cinti VSURG 2021

A novel technique to incorporate the sacrotuberous ligament in perineal herniorrhaphy in 47 dogs

How many dogs were bilaterally affected?
% minor post-op complications?
% major post-op comp?
% recurrence?
RF for complications?

Answer 13

Bilateral hernias in 36% (17/46)

Minor comp: 21% (10/47)
Major comp: 0%

Recurrence: 0%

RF for comp: increasing age, doing sx on a recurrent PH

Question 14

Tobias VSURG 2022

Perineal hernia repair in dorsal recumbency in 23 dogs: description of technique, complications, and outcome

Intra op comp %?
Post-op comp %?

Recurrence rate? More common in who?

Answer 14

No intraop complications (0%)

Postop complications in hospital in 14 dogs (61%) and after release in 11 (48%)

Hernias reoccurred in 4/21 dogs (19%)

Reoccurrence tended to be more common in dogs that had undergone previous
herniorrhaphies (p = .053)

Conc - dorsal recumb with single staged abdominal & perineal possible

Question 15

Rossello JSAP 2023

Combined transposition of internal obturator and superficial gluteal muscles for perineal hernia treatment in dogs: 17 cases (2017-2020)

Bilateral %?
Surgical repair successful with both in what %?
Short term post-op comp %? what complications?
Recurrence %?

Answer 15

Bilateral in 29% (5/17) (Unilateral 71%)

All perineal hernias successfully repaired (100%) using a transposition of the internal obturator muscle to cover the ventral aspect and the superficial gluteal muscle to cover the dorsal aspect with minimal tension.

Short term comp 7/17 = 41%
Minor partial skin incision necrosis (5), SSI (2)

0% recurrence

Question 16

Hubers JSAP 2022

Outcome of surgical treatment of perineal hernia in cats: 36 cases (2013-2019)

% bilateral?
% major post-op comp? what comp?
% with short term post-op tenesmus?
% with good vs poor long-term outcome?

Answer 16

34/36 bilateral (94%)

1/36 (3%) - rectal prolapse needing revision sx

12/32 (38%) with post-op tenesmus, resolved in 9/12 (75%)

Good outcome in 23/31 (74%)
Poor in 5/31 (16%)

Question 17

Åhlberg VRU 2022

CT imaging of dogs w/ perineal hernia reveals large prostates w/ morphological & spatial abnormalities

What were overall prostate differences between dogs with PH and control (intact, age-matched, male) dogs?

Answer 17

(Stat sig findings) - Dogs w/ PH had larger prostates, that more often contained cysts, & had larger cyst diameters than age-matched controls.

Prostates of PH dogs also contained paraprostatic cysts (17.4%) & focal mineralizations (32.6%) which were absent in controls.

Abnormal rotation & location of the prostate were common in dogs w/ PH.

NOTE - CT is appropriate adjunctive diagnostic for PH in males!

Question 18

Sabattini JSAP 2019

Cytological differentiation between benign and malignant perianal gland proliferative lesions in dogs: a preliminary study

% accuracy in 13 cytological criteria that showed promise?

Is pre-sx cyto helpful to differentiate benign vs malignant?

Answer 18

13 cytological criteria showed promise to distinguish benign from malignant – 87% accuracy

Yes - Cytological evaluation can provide useful information for presurgical differentiation between benign and malignant hepatoid gland proliferative lesions.

Question 19

Cantatore VSURG 2022

Submucosal resection via a transanal approach for treatment of epithelial rectal tumors - a multicenter study

% complications?
% recurrence?
Recurrence more likely with what 2 factors?

Answer 19

29% complications (27/93 dogs)

21% recurrence (20/93)

Recurrence more likely when complications or incomplete margins were present

Extra (Obvious):
- Overall survival sig. longer for benign tumors than carcinoma
- Recurrence associated with an increased risk of death

Question 20

Mayhew Vet Sx 2020

Evaluation of transanal minimally invasive surgery for submucosal rectal resection in cadaveric canine specimens

Successful?
Rectal penetration?

Answer 20

Submucosal rectal resection was successfully completed in all 6 dogs by using TAMI

Ease of placement scores
1/5 (very easy) in three dogs
2/5 (easy) in three dogs

The median length of resected specimens after fixation was 24.5 mm (range 9.8-26.5).

On dog had persistent fold of rectal mucosa protruded over the inner part of the ring

Sustained minor iatrogenic trauma

Median resection time 15 minutes, median suture time 17 minutes

In two of six dogs, suture was macroscopically visible on the serosal surface, but no dogs had evidence of iatrogenic full-thickness surgical penetration of the rectum.

All sections included good representation of mucosa, muscular is mucosa, and submucosa

No gross evidence of full-thickness penetration of the rectum

1 dog had mild leakage of the methylene blue dye emanating from the needle holes
5 dogs, some methylene blue could be seen dissecting between the planes fo the rectal wall without evidence of leakage

The median distance from the aborad extent of the suture closure line to the anocutaneous junction was 35 mm (range, 35-105).

Question 21

Shaughnessy JAVMA 2015 PQ - in our text book (:

Internal obturator muscle transposition for treatment of perineal hernia in dogs: 34 cases (1998-2012).

RR%?
MC Post op comp?
Bladder retroflexion?
RF for recurrence?

Tobias says?

Answer 21

The 1-year recurrence rate was 27.4%.
Tenesmus MC post-op complication

Bladder retroflexion at the time of initial evaluation or surgery was not a risk factor for complication (hazard ratio, 1.72)

Internal obturator muscle transposition was used for primary repair of perineal hernia in dogs.

Recurrence was recorded as long as 1 year after surgery. Tenesmus was a risk factor for the development of recurrence after treatment of perineal hernia with internal obturator muscle transposition.

Tobias: Approximately 10% of patients operated on unilaterally develop a hernia on the contralateral side from 1 month to 3 years after surgery. The presence of urinary bladder retroflexion has no effect on the complication rate.

Question 22

Morello JSAP 2015 PQ - in our text book (:

Modified semitendinosus muscle transposition to repair ventral perineal hernia in 14 dogs

What did they do?
Conclusions?

Tobias says?

Answer 22

modified technique of semitendinosus muscle transposition for the repair of ventral perineal hernia.

In addition to ventral perineal hernia, unilateral and bilateral perineal hernia was also present in five and six of the dogs

Ventral perineal hernia was successfully managed by the modified semitendinosus muscle transposition with minor complications in all the dogs included in the study.

unilateral transposition of the medial half of the longitudinally split semitendinosus muscle consistently supported the ventral rectal enlargement in perineal hernia without obvious adverse effects.

Tobias: favourable for 12/14 dogs with ventral PH via split mm in combo with other sx. 2 dogs had recurrence (15%). swelling and tenesmus short term comp