Small animal surgery. The Pelvic Area

Small animal surgery Surgery atlas, a step-by-step guide

The pelvic area

Small animal surgery José Rodríguez Gómez Jaime Graus Morales María José Martínez Sañudo

Rectum Hernias Anus Vulva-vagina Urethra Testes Prepuce-penis

Surgery atlas, a step-by-step guide

The pelvic area Clinical cases Techniques

www.servet.es/english

THE VETERINARY PUBLISHING COMPANY SMALL ANIMALS

Small animal surgery

The Pelvic Area

Aimed at veterinarians, students, professors and professionals in this field.

TECHNICAL SPECIFICATIONS Authors: José Rodríguez Gómez,

Photographs, diagrams and real clinical cases explain, step by step, the methods of approach and resolution for the main surgical interventions in the rectal, anal and perineal zones.

Format: 23 x 29.7 cm Number of Pages: 296 Number of Pictures: 800 Binding: Hardcover ISBN: 978-84-92569-46-5 RRP: 85 e

An essential work for both practising professionals and surgery students.

María José Martínez Sañudo and Jaime Graus Morales.

Centro Empresarial El Trovador, planta 8, oficina I - Plaza Antonio Beltrán Martínez, 1 • 50002 Zaragoza - España Tel.: 976 461 480 • Fax: 976 423 000 • pedidos@grupoasis.com • Grupo Asís Biomedia, S.L.

THE VETERINARY PUBLISHING COMPANY

Small animal surgery. The pelvic area TABLE OF CONTENTS 1. General considerations for rectal, anal and perineal surgery General rules for surgery in the perineal area

2. Rectum Rectal prolapse Stenosis

3. Hernias Perineal hernia

4. Anus

8. Prepuce – penis Phimosis Paraphimosis Wounds Tumours Prolapse of the urethral mucosa Hypospadia

9. General techniques Urethral catheterisation of the cat Urethral catheterisation of the dog

Anal sacculitis

Cystocentesis

Anal neoplasia

Lumbosacral epidural anaesthesia

Perianal fistulas

Patient positioning

Tail fold disease

Purse string suture of the anus

Anal atresia

Episiotomy

5. Vulva – vagina Neoplasia Persistent hymen

Vasectomy Castration of the dog and cat Infraumbilical laparotomy Cystotomy

6. Urethra Urethral obstruction in the dog Feline lower urinary tract disease (FLUTD)

7. Testes Testicular neoplasia Ectopic testes Scrotal lesions

Centro Empresarial El Trovador, planta 8, oficina I - Plaza Antonio Beltrán Martínez, 1 • 50002 Zaragoza - España Tel.: 976 461 480 • Fax: 976 423 000 • pedidos@grupoasis.com • Grupo Asís Biomedia, S.L.

The pelvic area

Perineal hernia / Deferensopexy Perineal hernia. Case 5 / Deferensopexy Technical difficulty

Fig. 11. Both parts of the internal obturator muscle are sutured to the anal sphincter and to the coccygeus muscle.

Hypertrophy of the prostate, a common finding in older dogs, can be a mechanical hindrance to defecation when it is displaced into the pelvis by abdominal straining. As a result, the patient shows tenesmus and chronic constipation. The prostate acts like a battering ram on the pelvic diaphragm during defaecation efforts, thereby contributing, along with other causes already mentioned, to the weakening of the perineal muscles, leading to herniation.

In these cases, the prostate moves into the pelvic canal, dragging the bladder along, a reason why both structures can be contained in the hernia (fig. 1). Reduction of the hernia and repair of the hernial ring are insufficient in these cases to fully prevent recurrence.

On the next pages, the technique of deferensopexy is described. The aim of this technique is to fix the prostate and the bladder in the abdominal cavity, thus preventing their displacement towards the pelvis and recurrence of the hernia.

This technique is complementary to the earlier described techniques of herniorraphy, mesh implantation and muscular transpositions.

52

53

Fig. 1. Lateral radiograph of the abdomen of the Fig. 12. Next, the superficial gluteal muscle is

sutured to the most dorsal part of the external anal sphincter and ventrally, to the transposed obturator muscle.

In order to transpose the internal obturator, it is necessary to section its tendon of insertion. This increases the technical difficulty but allows the closing of large hernial defects.

patient, showing that the herniated content includes the prostate, which has dragged the bladder in a caudal direction into the pelvic canal. Radiographic examination includes a barium enema and a pneumocystogram.

Deferensopexy is a complementary surgical technique, particularly indicated for perineal hernias that involve the bladder and/or the prostrate.

See castration

Fig. 13. View of the surgical wound after suturing, showing the T-shaped incision that gives access to the insertion point of the superficial gluteal muscle on the greater trochanter of the femur.

page 264

Fig. 2. First, castration is performed, leaving the

patient with forceps on the vasa deferentia. Both incisions are left momentarily without sutures. Next, a parapenile laparotomy is performed.

The pelvic area

Perineal hernia / Deferensopexy Perineal hernia. Case 5 / Deferensopexy Technical difficulty

Fig. 11. Both parts of the internal obturator muscle are sutured to the anal sphincter and to the coccygeus muscle.

Hypertrophy of the prostate, a common finding in older dogs, can be a mechanical hindrance to defecation when it is displaced into the pelvis by abdominal straining. As a result, the patient shows tenesmus and chronic constipation. The prostate acts like a battering ram on the pelvic diaphragm during defaecation efforts, thereby contributing, along with other causes already mentioned, to the weakening of the perineal muscles, leading to herniation.

In these cases, the prostate moves into the pelvic canal, dragging the bladder along, a reason why both structures can be contained in the hernia (fig. 1). Reduction of the hernia and repair of the hernial ring are insufficient in these cases to fully prevent recurrence.

On the next pages, the technique of deferensopexy is described. The aim of this technique is to fix the prostate and the bladder in the abdominal cavity, thus preventing their displacement towards the pelvis and recurrence of the hernia.

This technique is complementary to the earlier described techniques of herniorraphy, mesh implantation and muscular transpositions.

52

53

Fig. 1. Lateral radiograph of the abdomen of the Fig. 12. Next, the superficial gluteal muscle is

sutured to the most dorsal part of the external anal sphincter and ventrally, to the transposed obturator muscle.

In order to transpose the internal obturator, it is necessary to section its tendon of insertion. This increases the technical difficulty but allows the closing of large hernial defects.

patient, showing that the herniated content includes the prostate, which has dragged the bladder in a caudal direction into the pelvic canal. Radiographic examination includes a barium enema and a pneumocystogram.

Deferensopexy is a complementary surgical technique, particularly indicated for perineal hernias that involve the bladder and/or the prostrate.

See castration

Fig. 13. View of the surgical wound after suturing, showing the T-shaped incision that gives access to the insertion point of the superficial gluteal muscle on the greater trochanter of the femur.

page 264

Fig. 2. First, castration is performed, leaving the

patient with forceps on the vasa deferentia. Both incisions are left momentarily without sutures. Next, a parapenile laparotomy is performed.

The pelvic area

Anus / Anal sacculitis

Before surgery ■

Remove faecal content from the rectum.

■

Do not use laxatives during 24 hours prior to surgery.

■

Empty the anal sacs and flush them with an antiseptic solution.

■

Shave and disinfect the surgical field.

See positioning of the patient

page 248

Fig. 6. By inserting the gel into the anal sacs, the antiseptic solution used to flush

the sacs is expelled.

In small breeds, half a cartridge is inserted in each sac, while in large breeds, an entire cartridge should be used for each side.

Fig. 11. The cavity that remains is irrigated with lukewarm saline to eliminate tissue remnants, clots and bacteria.

Fig. 12. To control haemorrhage, haemostatic forceps or bipolar coagulation are used. We recommend the latter option.

70

71

Fig. 7. Injection of the hot gel in the right anal sac.

Fig. 8. After preparation of the surgical field and plugging the anus, an elliptical

Note that the needle does not prevent the gel from flowing out when the sac is full. This avoids rupturing of the sac due to excessive distension.

skin incision is made around the fistula.

Fig. 13. The muscular layer and subcutaneous tissue are closed with absorbable monofilament 4/0 suture material. The same steps are carried out on the left.

Fig. 14. The skin wound is closed with interrupted, vertical mattress sutures, using monofilament non-absorbable material, making sure the knots are placed on the outer edge to avoid contact with faeces during defecation.

In case of sacculitis, the sac can rupture during the introduction of the gel. In order to avoid this, the gel should be injected slowly, making sure the needle does not completely seal off the opening of the duct, so that the gel can escape easily in case of high intraluminal pressure.

Fig. 9. Thanks to the gel, which has hardened, the sac can easily be identified

Fig. 10. Complete dissection of the anal sac. It is now only attached by its duct.

between the muscular fibres of the anal sphincter.

This makes dissection of the sac easier, minimising the risk of accidental perforation.

Next, the duct is ligated as close as possible to the anal wall. For this ligature, synthetic absorbable 3/0 material is used.

Fig. 15. Both anal sacs have been completely removed. Incisions into each sac reveal the gel that was used to facilitate their dissection.

The pelvic area

Anus / Anal sacculitis

Before surgery ■

Remove faecal content from the rectum.

■

Do not use laxatives during 24 hours prior to surgery.

■

Empty the anal sacs and flush them with an antiseptic solution.

■

Shave and disinfect the surgical field.

See positioning of the patient

page 248

Fig. 6. By inserting the gel into the anal sacs, the antiseptic solution used to flush

the sacs is expelled.

In small breeds, half a cartridge is inserted in each sac, while in large breeds, an entire cartridge should be used for each side.

Fig. 11. The cavity that remains is irrigated with lukewarm saline to eliminate tissue remnants, clots and bacteria.

Fig. 12. To control haemorrhage, haemostatic forceps or bipolar coagulation are used. We recommend the latter option.

70

71

Fig. 7. Injection of the hot gel in the right anal sac.

Fig. 8. After preparation of the surgical field and plugging the anus, an elliptical

Note that the needle does not prevent the gel from flowing out when the sac is full. This avoids rupturing of the sac due to excessive distension.

skin incision is made around the fistula.

Fig. 13. The muscular layer and subcutaneous tissue are closed with absorbable monofilament 4/0 suture material. The same steps are carried out on the left.

Fig. 14. The skin wound is closed with interrupted, vertical mattress sutures, using monofilament non-absorbable material, making sure the knots are placed on the outer edge to avoid contact with faeces during defecation.

In case of sacculitis, the sac can rupture during the introduction of the gel. In order to avoid this, the gel should be injected slowly, making sure the needle does not completely seal off the opening of the duct, so that the gel can escape easily in case of high intraluminal pressure.

Fig. 9. Thanks to the gel, which has hardened, the sac can easily be identified

Fig. 10. Complete dissection of the anal sac. It is now only attached by its duct.

between the muscular fibres of the anal sphincter.

This makes dissection of the sac easier, minimising the risk of accidental perforation.

Next, the duct is ligated as close as possible to the anal wall. For this ligature, synthetic absorbable 3/0 material is used.

Fig. 15. Both anal sacs have been completely removed. Incisions into each sac reveal the gel that was used to facilitate their dissection.

06.Cirugia.uretra_INGLES.qxd:06.Cirugia_uretra.qxd

19/5/11

10:17

Página 146

The pelvic area

■

■

■

Urethra / Urethral obstruction in the dog

Using a scalpel, the skin and subcutaneous tissue between the scrotum and caudal part of the os penis is incised (fig. 3).

■

Using a fine blade (nº 11), an incision is made in the urethra through its midline into the lumen, taking care to avoid damage to the corpora cavernosa (fig. 4).

■

If it is necessary to extend the incision, fine iris scissors should be used. Always follow the midline of the urethra.

■

Retractor penis muscle

If the surgeon is inexperienced or if appropriate surgical material to reconstruct the urethra is not available, it is better to leave the penile wound unsutured to avoid excessive fibrosis. In this situation, local haemorrhage is highly probable during recovery from anaesthesia. This complication will be present for 4 or 5 days post-surgery, particularly when the patient urinates.

Ideally, the urethra and penis should be sutured to avoid postoperative bleeding and for reconstruction of infiltration of urine into the subcutaneous tissue, which can cause cellulitis and focal necrosis (fig. 6).

Finish by suturing the skin using the surgeon's technique of choice. (fig. 7).

Do not forget to have the calculi analysed to aid selection of appropriate dietary management to prevent or reduce the risk of recurrence.

Fig. 3. The retractor penis muscle is located,

dissected and moved to the side to access the urethra.

After surgery

Flush the operating field regularly with lukewarm saline to prevent exposed tissues drying out.

The urinary catheter is left in place for 2 days to ensure elimination of urine.

If the patient is not catheterised and urethral inflammation develops during the immediate postoperative period, or if blood clots obstruct the urethra, urinary retention may recur. Should this happen, the urinary tract will need to be catheterised again, risking damage to the operated area, rupture of sutures and exacerbating inflammation. This may result in excessive cicatricial fibrosis.

The main problem with leaving the catheter in place is the risk of ascending infection. Broad-spectrum antibiotics that undergo renal excretion (e.g. amoxicillin & clavulanic acid) are recommended while waiting for sensitivity testing results.

146

Fig. 4. Incising the urethra will cause bleeding; try to

incise in the midline to avoid excessive bleeding (due to cutting into the corpora cavernosa).

The placement of stay sutures will help to visualise the urethral lumen without damaging the urethral mucosa.

■

■

Fig. 6. Suture the urethra with absorbable 5/0 or 6/0 synthetic monofilament material using simple interrupted sutures.

Try to include as little tissue as possible, without compromising the stability of the suture.

Remove the calculi with fine dissecting forceps and by flushing lukewarm saline through the urinary catheter.

Once the obstructions have been removed, the catheter is passed into the bladder, making sure that there are no more calculi (fig. 5).

Fig. 7. In this case, an intradermal suture was placed using non-absorbable

monofilament synthetic material.

Fig. 5. The catheter is visible in the urethrotomy

wound.

Possible complications Bleeding for several days after surgery if the urethra is not sutured.

In some cases, bleeding is profuse and a causes concern for the owner and veterinarian. To minimise bleeding, suture the wound using fine absorbable synthetic material. If the wound cannot be closed, warn the owner, hospitalise the patient and control urethral bleeding by applying pressure with a gauze swab, especially after urinating.

Cicatricial stenosis results from marked fibrosis in the area following excessive trauma, inflammation or urethral lesions caused by calculi or surgical intervention.

To prevent this, operate promptly, avoid repeated urethral catheterisations, do not attempt to push the uroliths with the catheter and try urohydropropulsion and if you perform an urethrotomy, do so with care (and in the most atraumatic way) and use absorbable synthetic monofilament material.

If stenosis occurs, the surgeon will have to resort to permanent urethrostomy (see case 3).

147

06.Cirugia.uretra_INGLES.qxd:06.Cirugia_uretra.qxd

19/5/11

10:17

Página 146

The pelvic area

■

■

■

Urethra / Urethral obstruction in the dog

Using a scalpel, the skin and subcutaneous tissue between the scrotum and caudal part of the os penis is incised (fig. 3).

■

Using a fine blade (nº 11), an incision is made in the urethra through its midline into the lumen, taking care to avoid damage to the corpora cavernosa (fig. 4).

■

If it is necessary to extend the incision, fine iris scissors should be used. Always follow the midline of the urethra.

■

Retractor penis muscle

If the surgeon is inexperienced or if appropriate surgical material to reconstruct the urethra is not available, it is better to leave the penile wound unsutured to avoid excessive fibrosis. In this situation, local haemorrhage is highly probable during recovery from anaesthesia. This complication will be present for 4 or 5 days post-surgery, particularly when the patient urinates.

Ideally, the urethra and penis should be sutured to avoid postoperative bleeding and for reconstruction of infiltration of urine into the subcutaneous tissue, which can cause cellulitis and focal necrosis (fig. 6).

Finish by suturing the skin using the surgeon's technique of choice. (fig. 7).

Do not forget to have the calculi analysed to aid selection of appropriate dietary management to prevent or reduce the risk of recurrence.

Fig. 3. The retractor penis muscle is located,

dissected and moved to the side to access the urethra.

After surgery

Flush the operating field regularly with lukewarm saline to prevent exposed tissues drying out.

The urinary catheter is left in place for 2 days to ensure elimination of urine.

If the patient is not catheterised and urethral inflammation develops during the immediate postoperative period, or if blood clots obstruct the urethra, urinary retention may recur. Should this happen, the urinary tract will need to be catheterised again, risking damage to the operated area, rupture of sutures and exacerbating inflammation. This may result in excessive cicatricial fibrosis.

The main problem with leaving the catheter in place is the risk of ascending infection. Broad-spectrum antibiotics that undergo renal excretion (e.g. amoxicillin & clavulanic acid) are recommended while waiting for sensitivity testing results.

146

Fig. 4. Incising the urethra will cause bleeding; try to

incise in the midline to avoid excessive bleeding (due to cutting into the corpora cavernosa).

The placement of stay sutures will help to visualise the urethral lumen without damaging the urethral mucosa.

■

■

Fig. 6. Suture the urethra with absorbable 5/0 or 6/0 synthetic monofilament material using simple interrupted sutures.

Try to include as little tissue as possible, without compromising the stability of the suture.

Remove the calculi with fine dissecting forceps and by flushing lukewarm saline through the urinary catheter.

Once the obstructions have been removed, the catheter is passed into the bladder, making sure that there are no more calculi (fig. 5).

Fig. 7. In this case, an intradermal suture was placed using non-absorbable

monofilament synthetic material.

Fig. 5. The catheter is visible in the urethrotomy

wound.

Possible complications Bleeding for several days after surgery if the urethra is not sutured.

In some cases, bleeding is profuse and a causes concern for the owner and veterinarian. To minimise bleeding, suture the wound using fine absorbable synthetic material. If the wound cannot be closed, warn the owner, hospitalise the patient and control urethral bleeding by applying pressure with a gauze swab, especially after urinating.

Cicatricial stenosis results from marked fibrosis in the area following excessive trauma, inflammation or urethral lesions caused by calculi or surgical intervention.

To prevent this, operate promptly, avoid repeated urethral catheterisations, do not attempt to push the uroliths with the catheter and try urohydropropulsion and if you perform an urethrotomy, do so with care (and in the most atraumatic way) and use absorbable synthetic monofilament material.

If stenosis occurs, the surgeon will have to resort to permanent urethrostomy (see case 3).

147

The pelvic area

General techniques / Episiotomy

Episiotomy Technical difficulty

This technique is used to create surgical access to the interior of the vestibule and vagina to: excise polyps or tumours, repair tears, aid foetal expulsion during parturition, etc.

Fig. 2. The first step of an episiotomy is the

placement of two Doyen forceps on each side of the incision line to reduce bleeding.

The patient should be placed in sternal recumbency with the hindquarters elevated. The tail should be securely tied away from the operative field and a purse string suture should be placed around the anus (fig. 1).

254

See patient positioning

page 248

See purse string suture of the anus

page 252

To avoid bleeding, it is very useful to place two intestinal Doyen forceps on both sides of the dorsal midline where the incision will be made; one blade of the forceps is in the vagina, the other on the outside (fig. 2).

The incision is made from the dorsal commissure of the labia of the vulva, along the midline, to just below the anal sphincter (figs. 3 and 4).

The muscles and vaginal wall can be cut with scissors (figs. 5 and 6).

The bleeding, which is usually fairly light, can be easily controlled with diathermy, haemostatic forceps or a ligature if necessary.

Whatever the surgical procedure, it is very important to catheterise the urethra to identify it at all times and avoid damage (fig. 7).

The episiotomy can be closed in three layers (figs. 8-12). The first layer, the vaginal mucosa, is closed with a continuous suture using absorbable 2/0 or 3/0 suture material; the second layer, the muscle and subcutaneous tissue, in the same way and finally the skin is closed with simple interrupted sutures or with an intradermal suture. It is important to ensure perfect approximation of the wound edges at the vulvar commissure, avoiding unevenness of the wound edges. Finally, the use of an Elizabethan collar will prevent licking of the wound and subsequent inflammation.

255

Fig. 3. Next, a skin incision is made in the perineal

midline. The incision extends from the dorsal commissure of the vulva towards the anus, as far as is necessary to obtain comfortable access to the inside of the vagina. It is important to conserve the anal sphincter.

The most common complications of procedures requiring an episiotomy are bleeding and accidental damage to the urethra. These can be avoided by making the incision exactly in the perineal midline and identifying the urethra with a catheter.

Fig. 4. The incision is deepened through the Fig. 1. The patient is placed in sternal recumbency,

with the hindquarters on the edge of the table and the tail carefully tied back.

subcutaneous tissue and the muscular layer of the vaginal wall. Keep to the midline and use diathermy to reduce bleeding.

The pelvic area

General techniques / Episiotomy

Episiotomy Technical difficulty

This technique is used to create surgical access to the interior of the vestibule and vagina to: excise polyps or tumours, repair tears, aid foetal expulsion during parturition, etc.

Fig. 2. The first step of an episiotomy is the

placement of two Doyen forceps on each side of the incision line to reduce bleeding.

The patient should be placed in sternal recumbency with the hindquarters elevated. The tail should be securely tied away from the operative field and a purse string suture should be placed around the anus (fig. 1).

254

See patient positioning

page 248

See purse string suture of the anus

page 252

To avoid bleeding, it is very useful to place two intestinal Doyen forceps on both sides of the dorsal midline where the incision will be made; one blade of the forceps is in the vagina, the other on the outside (fig. 2).

The incision is made from the dorsal commissure of the labia of the vulva, along the midline, to just below the anal sphincter (figs. 3 and 4).

The muscles and vaginal wall can be cut with scissors (figs. 5 and 6).

The bleeding, which is usually fairly light, can be easily controlled with diathermy, haemostatic forceps or a ligature if necessary.

Whatever the surgical procedure, it is very important to catheterise the urethra to identify it at all times and avoid damage (fig. 7).

The episiotomy can be closed in three layers (figs. 8-12). The first layer, the vaginal mucosa, is closed with a continuous suture using absorbable 2/0 or 3/0 suture material; the second layer, the muscle and subcutaneous tissue, in the same way and finally the skin is closed with simple interrupted sutures or with an intradermal suture. It is important to ensure perfect approximation of the wound edges at the vulvar commissure, avoiding unevenness of the wound edges. Finally, the use of an Elizabethan collar will prevent licking of the wound and subsequent inflammation.

255

Fig. 3. Next, a skin incision is made in the perineal

midline. The incision extends from the dorsal commissure of the vulva towards the anus, as far as is necessary to obtain comfortable access to the inside of the vagina. It is important to conserve the anal sphincter.

The most common complications of procedures requiring an episiotomy are bleeding and accidental damage to the urethra. These can be avoided by making the incision exactly in the perineal midline and identifying the urethra with a catheter.

Fig. 4. The incision is deepened through the Fig. 1. The patient is placed in sternal recumbency,

with the hindquarters on the edge of the table and the tail carefully tied back.

subcutaneous tissue and the muscular layer of the vaginal wall. Keep to the midline and use diathermy to reduce bleeding.