Ch 94 - Rectum, Anus, Perineum

Question 1

Chen JAVMA 2022

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

Answer 1

15 dogs had apocrine gland anal sac adenocarcinoma, and 1 had a collision tumor. No dogs had intraoperative complications; 1 dog had a minor postoperative complication (paraparesis) that resolved. The median duration of postoperative follow-up was 286 days (range, 67 to 777 days). One dog had confirmed local disease recurrence 290 days after surgery, and 1 had suspected local disease recurrence 203 days after surgery and was euthanized because of systemic disease progression.

CONCLUSIONS AND CLINICAL RELEVANCE The modified closed anal sacculectomy was well tolerated in this sample of dogs, with minimal short-term complications. This study provided evidence to justify evaluation of the procedure in a larger number of dogs and assessment of the effects of procedural modifications on postoperative complication rates and time to local recurrence.

A mosquito hemostat was placed into the affected anal sac duct, and a skin incision was made along the length of the duct with a scalpel blade (Figure 1). Monopolar electrocautery was used to incise subcutaneous tissue and anal sphincter muscle fibers to isolate the duct. The hemostat was removed and opened; one side of the jaws was placed into the duct, and the duct was clamped in the hemostat to assist with manipulation and traction. Electrocautery was used to dissect the duct, anal gland, and associated tumor from surrounding anal sphincter fibers and subcutaneous tissues. The external anal sphincter tissue was apposed with absorbable monofilament suture in a simple interrupted pattern, and

Question 2

Schlag JSAP 2020

Comparison of methods to determine primary tumour size in canine apocrine gland anal sac adenocarcinoma

Answer 2

One hundred sixteen tumours from 107 dogs were included. There was moderate agreement between maximal dimension of the primary tumour measured by CT compared to formalin-fixed tissue and digital palpation. There was no significant difference in median maximum dimension between the measurement methods. Vascular invasion, CT stage, digital rectal examination stage and formalin-fixed tissue stage were significantly associated with metastasis at presentation, while mitotic index of the primary tumour was not. Dogs with tumours >2.5 cm (tumour-stage 2) were significantly more likely to present with metastatic disease. C linical Significance: In canine apocrine gland anal sac adenocarcinoma, primary tumour size, tumour-stage and vascular invasion are strong predictors of metastasis at presentation.

Question 3

Sandoval JSAP 2022

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

Answer 3

Eight cats were included in the study of which four of eight developed minor and self-limiting complications including defaecatory complications in three cases and superficial corneal ulceration in one case. No cat developed permanent faecal incontinence. No long-term postoperative complication was recorded. Median surgical time was 35 minutes (range, 20 to 42). Median hospitalisation time was 1.5 days (range, 1 to 4). The incidence of short-term minor complications is higher than previously reported in dogs, although this might be in agreement with a reported higher incidence in dogs smaller than 15 kg. Clinical Significance: Anal sacculectomy for non-neoplastic anal sac disease is a safe procedure in cats with relatively high rate of short-term but self-limiting, minor, postoperative complications

Question 4

Sutton JSAP 2022

Computed tomographic staging of dogs with anal sac adenocarcinoma

Answer 4

A population of 70 dogs were included in the study. No association was found between anal sac mass size and presence or absence of iliosacral lymph node enlargement. The prevalence of local metastatic disease characterised by iliosacral lymphadenomegaly in this study was 71%, with pulmonary metastases identified in 11% of cases. There were no cases of distant pulmonary metastasis without concurrent locoregional lymphadenomegaly.
C
linical Significance: In our population of dogs local metastatic spread of anal sac adenocarcinoma was common, with a relatively low prevalence of pulmonary metastasis. The study demonstrates the importance of thorough rectal examination and/or imaging to assess the iliosacral lymph centre in this disease irrespective of the size of the anal sac mass

Question 5

Bitton Vet Surg 2020

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

Answer 5

Cadavers were positioned in right and left lateral recumbency to free the origin and insertion of the ipsilateral SGM except for muscle fibers originating on the first tail vertebra and sacrotuberous ligament.

The dogs were placed in ventral recumbency to approach the perineum and rotate the muscle flaps. The insertions of the SGM were sutured together ventral to the anal sphincter muscle. The dorsal border of the overlapping tendons was sutured to the anal sphincter muscle, and the ventral border was sutured to the ischiourethralis muscle. The amount of overlap between bilateral flaps was measured. The SGM flaps were used to revise recurrent perineal hernias in three dogs.

Results: Superficial gluteal muscle flaps were created without damage to the blood supply in all dogs. The overlap between the bilateral flaps ventral to the anal sphincter measured 0 to 2.4 cm.

No recurrence was detected at follow-up (6-12 months) in the three dogs treated with these flaps.

Conclusion: Superficial gluteal muscle flaps were mobilized without damage to the blood supply and crossed the midline ventral to the anal sphincter. Flaps were used successfully to repair ventral perineal hernias in three dogs. Clinical significance: Bilateral SGM flaps can be considered to repair ventral perineal hernias.

Question 6

Bitton Vet Surg 2020
Use of bilateral superficial gluteal muscle flaps
for the repair of ventral perineal hernia in dogs:
A cadaveric study and short case series

Answer 6

Question 7

Bitton Vet Surg 2020
Use of bilateral superficial gluteal muscle flaps
for the repair of ventral perineal hernia in dogs:
A cadaveric study and short case series

Answer 7

Intra op photo of use of the SGM flap

Question 8

Cinti Vet Surg 2021

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

Answer 8

Twenty-eight of 47 dogs were medium or large breeds.
The primary clinical sign was tenesmus in 43 dogs and dysuria-stranguria in four dogs.

Bilateral hernias were detected in 17 dogs. No intraoperative complications occurred.

Median surgical time was 50 minutes for unilateral PH and 120 minutes for bilateral PH.

Minor postoperative complications consisting of surgical wound swelling (9), wound dehiscence (4), and temporary tenesmus (2) occurred in 10 dogs.
No major complications or recurrence were reported.
The only factors associated with an increased risk of complications included increasing age (P = .019) and surgical treatment of a recurrent PH (P = .043).

Owners consistently reported good long-term outcomes.

Conclusion: The PH repair described in this study resulted in good long-term outcomes without major complications. Clinical significance: Placement of sutures around the sacrotuberous ligament represents an alternative during PH, but anatomical knowledge of the sciatic nerve and caudal gluteal vessels is required.

Question 9

Cinti Vet Surg 2021
A novel technique to incorporate the sacrotuberous ligament in perineal herniorrhaphy in 47 dogs

Answer 9

Description of surgical procedure:
The proximal half of the sacrotuberous ligament was bluntly dissected from the surrounding tissue by using right-angle forceps. Two different methods were used to incorporate the sacrotuberous ligament. When a nonswaged suture needle was used, the ends of multiple sutures were grasped by the tip of the right-angle forceps and passed closely around the sacrotuberous ligament in one single maneuver; a needle was then loaded on the free end of each suture medial to the sacrotuberous ligament. When a swaged suture needle was used, the free ends of multiple sutures were grasped by the tip of the right-angle forceps and passed closely around the sacrotuberous ligament in a single maneuver, from medial to lateral, with the needle remaining medial to the sacrotuberous ligament. After suture placement, constant traction of the sutures was applied perpendicular to the sacrotuberous ligament for 1 minute while intraoperative oscillometric noninvasive mean arterial blood pressure (MAP), systolic arterial blood pressure (SAP), diastolic arterial blood pressure (DAP), and heart rate (HR) were carefully monitored as an indirect evaluation pain test to rule out sciatic nerve entrapment. All sutures were preplaced from dorsal to ventral incorporating coccygeal, levator ani, and external anal sphincter; while the internal obturator muscle was involved only by the most ventral sutures (Figures 2 and 3, Video S1). A digital rectal examination

Question 10

Cantatorre Vet Surg 2022

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

Answer 10

Duration of follow up was 708 days (range, 25-4383).

Twenty-seven dogs (29%) developed complications.

Recurrence was identified in 20/93 (21%), with 12/20 recurrent masses treated with repeat submucosal resection.

Median survival was not reached in any group. The 1-,2-, 5-year survival rates for carcinomas were 95%, 89%, and 73% respectively.

However, overall survival was longer for benign tumors than carcinomas (P = .001).

Recurrence was more likely when complications (P = .032) or incomplete margins (P = .023) were present. Recurrence was associated with an increased risk of death (P = .046).

Conclusion: Submucosal resection of both benign and malignant rectal masses was associated with a low rate of severe complications and prolonged survival in the 93 dogs described here. Clinical significance: Submucosal resection is a suitable technique for resection of selected rectal masses.

Question 11

Tobias Vet Surg 2022

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

Answer 11

Results: Internal obturator muscle transposition (IOMT) was performed in 22 dogs, and polypropylene mesh repair was performed in one dog. Transection of the internal obturator tendon was feasible in all dogs undergoing IOMT. Eighteen dogs underwent abdominal pexy procedures, castration, or both during the same anesthetic period. No intraoperative complications were noted. Postoperative complications were noted in the hospital in 14 dogs and after release in 11. Incisional infection/drainage and persistent urinary incontinence were reported in four and two dogs, respectively. Hernias reoccurred in four dogs and tended to be more common in dogs that had undergone previous herniorrhaphies (p = .053). Recurrence rates were lowest in dogs that had no prior hernia repair or organ pexy (p = .035). Conclusion: Perineal hernia repair was feasible in dorsal recumbency. Complication and recurrence rates of perineal herniorrhaphy in dorsal recumbency were similar to those reported for dogs undergoing the procedure in sternal recumbency. Clinical significance: Positioning of patients for perineal hernia repair can be dictated by surgeon preference. Perineal hernia repair in dorsal recumbency allows a single-stage abdominal and perineal approach without repositioning.

Question 12

Tobias Vet Surg 2022
Perineal hernia repair in dorsal recumbency in 23 dogs: Description of technique, complications, and outcome

Answer 12

Question 13

Ahlberg JAVMA 2024

Treatment of canine perineal hernia with a fascia lata graft is noninferior to the elevation of the internal obturator muscle: a prospective randomized trial of 66 dogs

Answer 13

To compare the recurrence rate after herniorrhaphy of canine perineal hernia (PH) using elevation of the internal obturator muscle (EIOM) or fascia lata graft (FLG) and assess how clinical signs related to defecation evolve during 12 months postoperatively.

METHODS Dogs were randomized into 2 groups (EIOM = 36; FLG = 30)

RESULTS In 63 dogs attending the 12-month follow-up, the recurrence rate was 8.8% (3/34) in the EIOM and 10.3% (3/29) in the FLG group.

The CI (–11.94% to 14.99%) was below the pre-defined margin, indicating the noninferiority of FLG. After surgery, the DSS decreased (P < .001), remaining low during the follow-up.

CLINICAL RELEVANCE FLG was non-inferior to EIOM when considering recurrence. The DSS decreased postoperatively and complications were uncommon. FLG is a useful alternative for the treatment of canine PH.

Need the description of FLG harvest from
Bongartz A, Carofiglio F, Balligand M, Heimann M,
Hamaide A. Use of autogenous fascia lata graft for perineal herniorrhaphy in dogs. Vet Surg. 2005;34(4):405–413. doi:10.1111/j.1532-950X.2005.00062.x

Question 14

Andries Vet Surg 2020

Identification of cutaneous arteries of the perineal and caudal thigh region: A cadaveric study in 12 cats

Answer 14

Nonselective barium sulfate angiography was performed via injection of the descending aorta. Skin excised from the perineum and thighs was evaluated via gross inspection and radiography to identify angiosomes. Results: The dorsal perineal artery had a robust angiosome on the caudal thigh in 10 of 12 cadavers. The artery exited the ischiorectal fossa along the muscular furrow between the biceps femoris and semitendinosus muscles and passed sagittally toward the popliteal fossa in those 10 specimens. All cadavers had a consistent angiosome based on the ventral perineal artery, which was located on the caudomedial thigh. All cadavers also had a consistent angiosome from a cutaneous branch of the popliteal artery, which traveled in a distal to proximal direction starting at the popliteal fossa. Conclusion: The dorsal perineal artery had a large cutaneous angiosome on the caudal thigh, which was consistent in most cats. The ventral perineal artery and cutaneous branch of the popliteal artery had consistent but smaller cutaneous angiosomes. Clinical significance: The axial pattern flaps of the cutaneous branches of the dorsal and ventral perineal arteries and the popliteal artery provide a robust arterial blood supply to the skin of the perineum and the caudal thigh. These three flaps may therefore have adequate vascular supply to consistently survive in most cats.

Question 15

Andries Vet Surg 2020
Identification of cutaneous arteries of the perineal and caudal thigh region: A cadaveric study in 12 cats

Answer 15

Diagram for outline of base of flaps correlating to the 3 arteries

Question 16

Fontes JAVMA 2023

Long-term outcomes associated with a modified
versus traditional closed anal sacculectomy
for treatment of canine anal sac neoplasia

Answer 16

Modified approach as described by Chen

35 and 55 dogs, respectively, underwent the modified or traditional closed anal sacculectomy procedure. Minor postoperative complications that resolved with minimal intervention occurred in 5 of 35 (14.3%) modified approach dogs and 12 of 55 (21.8%) traditional approach dogs. Tumor recurrence was confirmed in 8 of 35 (22.9%) modified and 8 of 55 (26.4%) traditional approach dogs and was suspected in 3 of 35 (8.6%) and 6 of 55 (13.2%; P = .68), respectively. Confirmed metastatic disease was identified in 8 of 35 (22.9%) and 14 of 53 (26.4%) modified and traditional approach dogs, respectively, and was suspected in 4 of 35 (11.4%) and 7 of 53 (13.2%). Sixty-three (70%) dogs survived to study conclusion. CLINICAL RELEVANCE No benefits in complication rate or local recurrence were identified in dogs following the modified approach as opposed to the traditional closed anal sacculectomy technique.

Question 17

Griffin JAVMA 2023

Short- and long-term outcomes associated
with anal sacculectomy in dogs with massive
apocrine gland anal sac adenocarcinoma

Answer 17

Massive >5cm

RESULTS At the time of anal sacculectomy, 19 (68%) dogs underwent concurrent iliosacral lymph node extirpation, including 17 of 18 (94%) dogs with suspected nodal metastasis preoperatively. Five (18%) dogs experienced grade 2 intraoperative complications. Ten (36%) dogs experienced postoperative complications, including 1 grade 3 and 1 grade 4 complication. No dogs had permanent fecal incontinence, tenesmus, or anal stenosis. Nineteen dogs received adjuvant chemotherapy, radiation, or both. Local recurrence occurred in 37% of dogs. Dogs with lymph node metastasis at surgery were more likely than dogs without metastasis to develop new/progressive lymph node metastasis (10/17 [59%] vs 0/10 [0%]; P = .003) and distant metastasis (7/17 [41%] vs 0/10 [0%]; P = .026). Median PFI was 204 days (95% CI, 145 to 392). Median OS was 671 days (95% CI, 225 to upper limit not reached). Nodal metastasis at the time of surgery was associated with shorter PFI (P = .017) but not OS (P = .26). Adjuvant therapy was not associated with outcome. CLINICAL RELEVANCE Dogs with massive AGASACA experienced prolonged survival following anal sacculectomy despite a high incidence of local recurrence and metastasis. Lymph node metastasis at the time of surgery was a negative prognostic indicator for PFI but not OS.

Question 18

Rossello JSAP 2023

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

Answer 18

Seventeen dogs were included in the study. Twelve dogs were presented with unilateral perineal hernia and five dogs with bilateral perineal hernias. Mean duration of clinical signs before presentation was 9 months. All perineal hernias were successfully repaired using a transposition of the internal obturator muscle to cover the ventral aspect of the perineal hernia and the superficial gluteal muscle to cover the dorsal aspect of the hernia with minimal tension. All dogs regained normal defecation within 24 hours post-surgery. Average follow-up time was 16 months. No recurrence of clinical signs or rectal deviation was observed. Five dogs developed a superficial minor partial necrosis of the T-shaped incision and two had surgical site infections. Clinical Significance: Perineal herniorrhaphy using a combined transposition of the internal obturator and the superficial gluteal muscles is feasible and offered excellent results in this cohort of dogs. It may be considered as a technique for repairing chronic and extensive unilateral and bilateral perineal hernias.

Question 19

Rossello JSAP 2023

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

Answer 19

Description of the SGM portion of the surgery:

The superficial gluteal muscle was manipulated to cover the dorsal aspect of the hernia and two to three sutures used to appose the caudal part of the superficial gluteal muscle to the dorsal portion of the external anal sphincter muscle. Two sutures were used ventrally to attach the superficial gluteal muscle to the internal obturator muscle, and finally two to three sutures were used to suture the superficial gluteal muscle to the tail musculature (intertransversarius ventralis caudalis and sacrocaudalis ventralis lateralis muscles) (Fig 6). The surgical site was lavaged with sterile saline. The subcutaneous layer was closed using a simple continuous pattern using polydioxanone 2/0 or 3/0 USP, and the skin closed using a Ford interlocking pattern with monofilament polyamide 2/0 or 3/0 USP. A digital rectal examination was performed immediately after closure to ensure no sutures had penetrated the rectal mucosa and to assess the security of the PH repair was satisfactory. Entire males were

Question 20

Mayhew Vet Surg 2020

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

Answer 20

Submucosal rectal resection was successfully completed by using TAMIS in all dogs. The median length of resected specimens after fixation was 24.5 mm (range 9.8-26.5). 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. The median distance from the aborad extent of the suture closure line to the anocutaneous junction was 35 mm (range, 35-105). Conclusion: Submucosal resection of the canine rectal wall was feasible in large breed dogs by using TAMIS. No evidence of full-thickness penetration of the rectal wall was seen in these cadaveric specimens. Clinical significance: Transanal minimally invasive surgery may provide an alternative minimally invasive approach for resection for benign adenomatous rectal polyps in large breed dogs that might otherwise require a rectal pullthrough.

From paper introduction, regarding TAMIS
Similar complications are reported in humans with rectal neoplasia, and, in an effort to reduce this level of morbidity, alternatives to more invasive techniques have been performed with success in clinical patients. The first generation of minimally invasive transanal approaches was termed transendoscopic microsurgery (TEM).11 Advantages were found compared with traditional transanal excision techniques, including higher proportions of clear surgical margins and less frequent recurrence compared with transanal approaches.11 However, the procedure required a very expensive purpose- built surgical access platform and specialized instruments.12 It was also limited by restrictive working space and had a steep learning curve. In 2010, transanal minimally invasive surgery (TAMIS) was introduced and has been adopted more widely in the human colorectal surgery community because of reduced costs and the ability to use traditional laparoscopic instruments already available in most centers.13 The TAMIS platform also allowed greater maneuverability of instrumentation compared with the TEM platform. In many centers, TAMIS has now become the standard of care for most endoscopically unresectable polyps and early stage (T1) rectal cancers.14-16

Question 21

Hubers JSAP 2022

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

Answer 21

Thirty-six cats were included in the study: 34 had bilateral and two unilateral hernias. Of these 36, 24 (67%) were male neutered with a median age of 10 (range: 1 to 18) years. The complication rate was low, however, one cat experienced a major postoperative complication: rectal prolapse requiring revision surgery 48 hours postsurgery. Short-term outcomes were available for 32 of 36 (89%) cats. Of the 32, 23 were examined 6 weeks postoperatively, and a telephonic consultation was performed for an additional nine of 32. Of the 23 cats examined directly, none had recurrence.

Overall 12 of 32 experienced short-term postoperative tenesmus which resolved in nine of 12 (75%). Long-term outcomes were available for 31 of 36 cats (86%), with a median of 18.5 (6 to 89) months follow-up.

A good outcome was achieved in 23 of 31 (74%) whereas three of 31 (10%) had fair outcomes and five of 31 (16%) had a poor outcome. Of the five cats with a poor outcome, two required subtotal colectomy to manage clinical signs related to megacolon, two were euthanised following a return of clinical signs, and one developed unilateral recurrence. Clinical Significance: Perineal hernia should be considered in cats presenting with tenesmus or recurrent obstipation. Surgical treatment of perineal hernias in cats can result in good owner-assessed longterm outcome.

Performed a modified IOMT
Appplication of the mattress suture with double-armed polypropylene from caudal to cranial through the middle of the external anal sphincter muscle (1), the base of the coccygeal muscle from medial to lateral (2) and the tendon of the internal obturator muscle from dorsal to ventral (3). This sequence is repeated to create a mattress suture with the double-armed polypropylene. Tied in the middle, then do two continuous sutures lines?