Chapter 61 - Penis and prepuce II surgery Flashcards
1
Q
What is a common cause of genital squamous cell carcinoma in horses?
A
Lack of pigmentation, particularly in older geldings or stallions.
2
Q
What is hypospadias?
A
A congenital defect where the urethral meatus is abnormally located.
3
Q
What conditions may accompany hypospadias in horses?
A
Chordee, incomplete prepuce, and meatal stenosis.
4
Q
How is hypospadias in horses usually managed if it causes discomfort?
A
By amputation of the malformed penile portion.
5
Q
What type of intersex condition is common in horses?
A
Male pseudohermaphroditism.
6
Q
How can a pseudohermaphrodite horse’s appearance be altered?
A
By amputation or repositioning of the genitalia.
7
Q
What is the most frequent neoplasm of the horse’s external genitalia?
A
Squamous cell carcinoma.
8
Q
What factors might predispose certain horse breeds to genital carcinoma?
A
Nonpigmented genitalia and chronic irritation from smegma.
9
Q
What virus is associated with genital squamous cell carcinoma in horses?
A
Equus caballus papillomavirus type 2 (EcPVpv2).
10
Q
What are common symptoms of advanced squamous cell carcinoma in horses?
A
Ulceration, necrosis, and possibly a malodorous discharge.
11
Q
What type of laser is used to excise squamous cell carcinoma on the external genitalia?
A
Carbon dioxide laser.
12
Q
What is a potential benefit of using a laser for excision over traditional methods?
A
It reduces postoperative swelling and has a thermal killing effect on marginal tumor cells.
13
Q
What surgical procedures may be necessary for horses with extensive neoplastic lesions on the genitalia?
A
Preputial reefing or partial phallectomy.
14
Q
What is the last-resort surgical procedure for extreme cases of neoplastic lesions?
A
Prescrotal urethrostomy with en bloc resection.
15
Q
What material is typically used in cryotherapy for squamous cell carcinoma?
A
Liquid nitrogen or CO₂.
16
Q
What is the ideal freezing and thawing cycle in cryotherapy for the best results?
A
A double, fast freeze–slow thaw cycle.
17
Q
Which topical drug is used for small genital lesions in horses?
A
5% 5-fluorouracil.
18
Q
How often is 5-fluorouracil applied to lesions?
A
Every 14 days.
19
Q
What intratumoral chemotherapy drug is used in combination with surgery for squamous cell carcinoma?
A
Cisplatin.
20
Q
Why is debulking a tumor before chemotherapy beneficial?
A
It lowers the tumor burden, making remaining cells more responsive to cisplatin.
21
Q
What side effect is avoided by administering cisplatin directly into the tumor bed during surgery?
A
There is no detrimental effect on wound healing.
22
Q
What treatment technique uses electrical pulses to improve drug delivery to neoplastic cells?
A
Electrochemotherapy.
23
Q
What effect does electroporation have on cisplatin efficacy?
A
It can increase cytotoxicity up to 70 times in vitro.
24
Q
What percentage of blood flow reduction occurs in tumors post-electroporation, aiding drug retention?
A
60–70%.
25
What is the maximum tolerated dose of doxorubicin for horses?
75 mg/m².
26
What medication is used alongside doxorubicin to minimize hypersensitivity reactions?
Antihistamines and nonsteroidal anti-inflammatory drugs.
27
At what temperature is the tumor heated during radiofrequency-induced hyperthermia?
50°C for 30 seconds.
28
What type of tumors in horses is hyperthermia commonly used for?
Sarcoids and ocular neoplasia.
29
What percentage of horses survived 18 months post-surgical therapy for genital carcinoma?
64.5%.
30
How does invasion of the cavernous tissue by carcinoma affect prognosis?
It indicates a poor prognosis due to higher metastatic potential.
31
What should be performed to detect abdominal metastases in cases of corporeal invasion?
Laparoscopic examination.
32
What is the main cause of cutaneous habronemiasis?
Larval infection by Habronema worms.
33
Where do these larvae typically cause lesions?
Prepuce and urethral process.
34
Which season sees higher incidence of habronemiasis?
Spring and summer.
35
What two immune reactions are associated with habronemiasis?
Granulomatous reaction and hypersensitivity.
36
What are common treatments for habronemiasis lesions?
Ivermectin and corticosteroids like prednisolone. Orally at 200 μg/kg, Prednisolone, administered orally at 1.5 mg/kg SID for 10 to 14 days, or diethylcarbamazine, administered orally at 1.5 mg/kg BID for 7 to 14 days
37
What condition causes blood in the ejaculate of stallions?
Hemospermia.
38
What commonly causes hemospermia related to the urethra?
Urethral rents.
39
What is a potential diagnostic tool for urethral rents?
Endoscopy.
40
What is a non-surgical treatment recommended for hemospermia?
Sexual abstinence.
41
What is the surgical method used to decrease pressure in the urethral lumen?
Perineal urethrotomy.
42
What alternative surgical procedure can be performed to treat hemospermia without exposing the urethral lumen?
Corpus spongiotomy.
43
What is a potential cause of hemospermia that might be detected in semen microscopically?
Septic seminal vesiculitis.
44
What technique may confirm bacterial seminal vesiculitis?
Transrectal ultrasonographic examination.
45
How might hemospermia related to bacterial urethritis be treated locally?
Topical application of antimicrobial drugs.
46
What surgical approach might restore preputial function affected by habronemiasis?
Elliptical resection of fibrotic areas.
47
What other diagnostic tx beside endoscopy is used for diagnosis of urethral rents?
Urethrography - the penis is radiographed after injecting 180 mL of barium suspension into the urethra. The barium is allowed to drain, 180 mL of air is injected to provide double contrast, and the penis is again radiographed.
48
In severe cases of habronemiasis affecting urination, what procedure is performed?
Amputation of the urethral process.
49
Figure 61-14. Hypospadias of the stallion in Figure 61-13 was accompanied by chordee, or an abnormal ventral curvature of the penis. Chordee caused this stallion to develop urine-induced dermatitis and discomfort during urination
50
Figure 61-13. Hypospadias of a stallion. The urethral meatus is located subcoronally and the internal lamina of the prepuce is complete. The stallion also had chordee
51
Figure 61-15. Perineal hypospadias in a 6-month-old colt. The colt is anesthetized and in dorsal recumbency
52
What COX inhibitor has been tried for metastatic squamous cell carcinoma?
Piroxicam.
53
What enzyme is associated with promoting metastasis in squamous cell carcinoma?
Cyclooxygenase-2 (COX-2).
54
What is a newly available generic chemotherapy drug for equine neoplasia?
Doxorubicin.
55
What anatomical structures can be sources of hematuria?
Kidney, ureter, bladder, urethra, or reproductive organs.
56
List three common causes of hematuria.
Renal calculi, vesicular neoplasia, pyelonephritis.
57
What is terminal hematuria, and what does it indicate?
Hematuria occurring at the end of urination; suggests a lesion at the proximal urethra or trigone of the bladder.
58
In which group is a urethral rent observed more frequently, stallions or geldings?
Geldings.
59
What anatomical feature might predispose horses to urethral rents at the ischial arch?
The sharp bend and narrow diameter of the urethral lumen at the ischial arch.
60
What anatomical feature might predispose horses to urethral rents at the ischial arch?
The sharp bend and narrow diameter of the urethral lumen at the ischial arch
61
Explain the effect of hydrodynamic forces on urethral rents at the ischial arch.
Increased hydrodynamic forces at the ischial arch can cause urethral damage due to high pressure on the thin lamina propria
62
What role does the corpus spongiosum (CSP) play in urethral hemorrhage?
CSP pressure may lead to bleeding through a urethral rent, especially as it remains high when urethral pressure drops.
63
Why is terminal hematuria less common in stallions than geldings?
CSP pressure in geldings is almost double that in stallions due to differences in cavernosal space volume.
64
Describe a characteristic finding on endoscopic examination of a urethral rent.
A 5-10 mm linear defect on the convex urethral surface near the ischial arch without inflammation.
65
What surgical technique is often used to treat urethral rents causing hematuria?
Perineal urethrotomy.
66
How does perineal urethrotomy treat hematuria?
By reducing vascular pressure in the CSP, preventing blood leakage through the rent.
67
What is corpus spongiotomy, and how does it compare to urethrotomy?
Incision into CSP without urethral penetration; as effective as urethrotomy in resolving hematuria
68
Horses affected with hemospermia caused by septic seminal vesiculitis should receive
antimicrobial therapy that is effective against the causative organism.
69
Figure 61-18. Massive granuloma on the internal preputial lamina caused by cutaneous habronemiasis. This mass was removed by segmental posthetomy.
70
What is the expected outcome of corpus spongiotomy based on studies?
Resolution of hematuria in the majority of horses treated.
71
how do you treat a urethral rent?
To prepare for primary closure of a urethral rent, an endoscope is inserted into the urethra so that the rent can be observed. Two 3.81-cm, 20-gauge needles are inserted through the skin of the perineum and advanced so that the shafts of the needles emerge in the urethral lumen at the proximal and distal ends of the rent. The perineum is incised as if a perineal urethrotomy was to be performed, but the incision extends only into the CSP and not through the urethral mucosa. The rent in the urethral mucosa is identified between the shafts of the needle and is closed, using endoscopic guidance, with USP size 3-0 absorbable suture material using a simple-continuous suture pattern. The sutures should incorporate the tunica albuginea of the CSP adjacent to the urethra. The perineal incision can be left open to heal by second intention, or it can be sutured in layers. Sutured layers should include the incisions into the tunica albuginea of the CSP at the urethral groove, the bulbospongiosus muscle, subcutaneous tissue, and skin.
72
What is the Adam’s procedure in segmental posthetomy?
A method to retain a paralyzed penis within the preputial cavity.
73
Administration of systemic AB to stallions with septic seminal vesiculitis is not effective, why?
Systemic administration of antimicrobial drugs to stallions affected with septic seminal vesiculitis is often ineffective because antimicrobial drugs diffuse poorly into the gland.
74
how do you perform the surgery of urethrotomy for hemospermia?
Simply incising the convex surface of the tunica albuginea of the CSP at the ischium, without exposing the lumen of the urethra (i.e., corpus spongiotomy), may be as effective as perineal urethrotomy for eliminating hemospermia
75
describe perineal urethrotomy
horse standing and sedated after administering epidural anesthesia A 6- to 8-cm vertical incision is created on the perineal raphe about 2 to 3 cm below the anus. The incision is extended through the skin, the paired retractor penis muscles, the bulbospongiosus muscle, the CSP, and the urethral mucosa (Figure 61-32).
76
Figure 61-32. Urethrotomy. A vertical incision has been created on the perineal raphe ventral to the anus. This incision extends through the skin and the paired retractor penis muscles, exposing the bulbospongiosus muscle. A vertical incision through this muscle and the underlying corpus spongiosum penis and urethral mucosa exposes the urethral lumen.
77
What is segmental posthetomy, and when is it indicated?
Resection of part of the preputial lamina; used for extensive preputial neoplasms or scars.
78
What precautions are necessary when performing segmental posthetomy?
Avoid cutting external pudendal vessels and ensure proper alignment of sutures.
79
Hemospermia has been reported to occur from urethral rents, the etiology of which is unknown - what is the CSP pressure increase
Hemorrhage from the CSP typically occurs at the end of ejaculation when contraction of the bulbospongiosus muscle causes pressure within the CSP to increase from 17 to nearly 1000 mm Hg
80
Why is a tourniquet used in segmental posthetomy?
To reduce bleeding during the procedure.
81
What postoperative care is recommended for segmental posthetomy?
Stallions should wear a ring for 2 weeks and be isolated from mares for 2-4 weeks.
82
What is the Bolz technique of phallopexy used for?
To permanently retract a paralyzed penis into the preputial cavity.
83
Why can the Bolz procedure not be used if the penis is still capable of erection?
Erection would disrupt the permanent retraction, risking surgical failure.
84
What surgical step is crucial in the Bolz technique?
Proper placement of anchoring sutures without penetrating the preputial cavity.
85
Describe Bolz tx of phallopexy
GA DR
The urethra should be catheterized for easy identification. A 10-cm longitudinal incision is made on the perineal raphe just caudal to the scrotum or scrotal scar (Figure 61-22, A) and the penis is bluntly separated from surrounding fascia, taking care to avoid damaging the surrounding large pudendal vessels (see Figure 61-22, B). The penis is retracted until the attachment of the internal preputial lamina onto the free body of the penis is visible at the cranial extent of the incision (see Figure 61-22, C).
T
he penis is anchored in this position with two heavy, nonabsorbable percutaneous sutures, one on each side of the penis, inserted through the attachment of the internal preputial lamina.
T
he anchoring sutures should penetrate the skin 2 to 4 cm from the incision at about the level of the middle of the incision. The sutures are inserted through the annular ring on the lateral surface of the penis, taking care to avoid entering the preputial cavity, the urethra, or cavernous tissue. An assistant should palpate the fornix of the preputial cavity during placement of the sutures through the attachment of the internal preputial lamina onto the free body of the penis to ensure that the sutures do not penetrate the preputial epithelium. The sutures exit the skin 2 to 3 cm from their entry points. They are tightened until the glans penis is flush with the preputial orifice and tied over rolls of gauze or large buttons to prevent the suture from cutting through the skin (see Figure 61-22, D). The subcutaneous tissue and skin are each closed separately.
T he percutaneous anchoring sutures are removed after 10 to 12 days, at which time adhesions of sufficient strength to maintain the penis in its retracted position have formed
86
What complication may arise if the penis is inadequately retracted in the Bolz procedure?
Urine-induced dermatitis due to exposure of the glans penis.
87
Describe the postop of the Bolz tx
The horse should be walked daily to minimize swelling, and heavy exercise can be resumed 2 to 3 weeks after the skin sutures have been removed. Closed castration can be performed at the same time as the Bolz tx
88
What is the purpose of amputation of the urethral process?
To treat granulomas or neoplastic lesions unresponsive to medical therapy.
89
What are two potential complications following amputation of the urethral process?
Hemorrhage and fibrosis.
90
Figure 61-22. (A) Bolz technique of phallopexy. A 10-cm incision is made on the perineal raphe just caudal to the scrotum. (B) The penis is bluntly separated from surrounding fascia, taking care to avoid damaging the surrounding large pudendal vessels. (C) The penis is retracted until the attachment of the internal preputial lamina onto the free body of the penis is visible at the cranial extent of the incision. The penis is fixed in this position with two heavy nonabsorbable percutaneous sutures. The sutures, one each side of the penis, are inserted through the attachment of the internal preputial lamina. (D) The sutures are tightened until the glans penis is flush with the preputial orifice and are tied over rolls of gauze or large buttons to prevent the suture from cutting through the skin. The subcutaneous tissue and skin are closed separately.
91
Describe surgical technique of urethral process amputation
A circumferential incision extending through the skin, CSP, and urethral mucosa is made around the base of the urethral process proximal to the affected tissue and distal to the anchoring hypodermic needles. The urethral mucosa is apposed to the epithelium of the remaining stump of the process with simple-interrupted or simple-continuous sutures of USP size 4-0 or 5-0 absorbable suture. The sutures should be closely spaced to compress the erectile tissue of the CSP. A simple-continuous suture pattern is probably more effective than a simple-interrupted one in compressing the erectile tissue of the CSP. The entire length of the process can be removed.
92
Figure 61-23. This urethral process was amputated to eliminate hemospermia caused by carcinoma of the urethral mucosa. The urethral process was stretched with tissue forceps, and two small-gauge needles were placed through the urethral process and the catheter at right angles to each other, proximal to the diseased portion of the urethral process, to anchor the urethral process to the catheter.
93
how do you prepare the penis for urethral process amputation?
The urethral process can be amputated with the horse standing and sedated after infiltrating the base of the urethral process with a local anesthetic agent, but the procedure is most easily and safely accomplished with the horse anesthetized and in dorsal recumbency. The penis is prepared for aseptic surgery and a urinary catheter is passed into the urethra. After placing traction on the urethral process with one or two Allis tissue forceps, two small-gauge needles (e.g., 23 or 25 gauge) are placed through the urethral process and the catheter at right angles to each other, proximal to the diseased portion of the urethral process (Figure 61-23). These needles anchor the urethral process to the catheter, making the incised margin of the process more stable and accessible for suturing.
94
Why is partial phallectomy indicated in cases of penile paralysis with extensive damage?
To prevent urethral stenosis and remove irreparably damaged tissue.
95
What is the Vinsot technique of partial phallectomy?
Removal of a triangular tissue section from the ventral penis and urethrostomy at the base.
96
What is an alternative closure method for the penile stump in the Vinsot technique?
Leaving it to heal by secondary intention.
97
Why is partial phallectomy beneficial when performed on a standing horse?
It can reduce anesthesia risks in debilitated horses or when financial constraints apply.
98
what is important to do 3 to 4 weeks before a partial phallectomy to avoid hemorrhage and dehiscence?
stallion should be castrated 3 to 4 weeks before partial phallectomy to avoid postoperative erection, which may lead to hemorrhage and dehiscence of the sutured stump.
99
describe the preparation of the horse before phallectomy
The procedure can sometimes be performed with the horse standing and sedated after anesthetizing the pudendal nerves or after performing a ring block proximal to the site of amputation but the procedure is most easily performed with the horse anesthetized and positioned in lateral or, preferably, dorsal recumbency. The urethra is catheterized with an equine male urinary catheter, and the penis is extended with gauze looped around the collum glandis. A tourniquet placed proximal to the proposed site of transection facilitates surgery.
100
The vinsot triangle is the removal of which structures?
A triangular section of tissue that includes epithelium, fascia, bulbospongiosus muscle, and CSP is removed from the ventrum of the penis proximal to the proposed site of transection, taking care not to enter the urethral lumen (Figure 61-24).
101
The vinsot triangle has which diamensions?
The triangle has a 2.5-cm base and 4-cm sides. Its apex points distad and is located about 4 or 5 cm proximal to the proposed site of transection
102
Figure 61-24. Vinsot technique of phallectomy. A triangular section of tissue is removed from the ventrum of the penis proximal to the proposed site of transection, taking care not to enter the urethral lumen. The exposed urethra is incised on its midline from the base to the apex of the triangle, and the incised edges of the urethra and the triangle’s epithelial border are apposed with absorbable sutures in a simple-interrupted pattern. A nonabsorbable ligature is placed around the penis distal to the apex of the triangle, and the penis is severed distal to the ligature.
103
describe the vinsot tx
The triangle has a 2.5-cm base and 4-cm sides. Its apex points distad and is located about 4 or 5 cm proximal to the proposed site of transection. The exposed urethra is incised on its midline from the base to the apex of the triangle, and the incised edges of the urethra and the triangle’s epithelial border are apposed with simple-interrupted or simple-continuous absorbable sutures. The sutures should include the tunica albuginea of the CSP and should be closely spaced to compress the erectile tissue of the CSP. A simple-continuous suture pattern is probably more effective than a simple-interrupted suture pattern in compressing the erectile tissue of the CSP. The diseased portion of the penis is removed 4 to 5 cm distal to the urethrostomy using a wedge-shaped incision. Large vessels on the dorsal and lateral aspects of the tunica albuginea are ligated with absorbable suture material, and the corporeal bodies are compressed with absorbable sutures placed through the tunica albuginea in an everting or appositional pattern. The penile or preputial integument is sutured with absorbable or nonabsorb sutures place in everting or appositional pattern nstead of suturing the end of the stump, the surgeon can leave it unsutured to heal by secondary intention. To prevent hemorrhage from the corporeal bodies, a tightly fixed, nonabsorbable ligature, such as a ligature of umbilical tape, is placed around the penis 2 to 3 cm distal to the apex of the triangle, before the penis is severed transversely 1 to 2 cm distal to the ligature. A bander castration device (Callicrate Bander) with a latex loop (ES-10) is effective in maintaining continuous, maximal pressure on the stump of the penis to prevent hemorrhage from the corporeal tissue and the vasculature (Figures 61-25 and 61-26).149
104
Figure 61-25. A bander castration device (Callicrate Bander) with a latex loop (ES-10) can be applied to the penis slightly proximal to the site of transection to prevent hemorrhage from the penile stump after partial phallectomy
105
Fig 1: Illustration of the main stages of the surgical procedure: (a) Creation of a perineal urethrostomy.
106
Fig 1: Illustration of the main stages of the surgical procedure: (b) Application of a Callicrate
Loop using the Callicrate Bander, approximately 2–3 cm proximal to the intended site of partial phallectomy
107
Fig 1: Illustration of the main stages of the surgical procedure: (c) Transection of the
penis and prepuce distal to the Callicrate Loop
108
Figure 61-26. When performing a partial phallectomy using the Vinsot technique, the surgeon can leave the transected end of the penis unsutured to heal by secondary intention. To prevent hemorrhage from the corporeal bodies, a tightly fixed nonabsorbable ligature is placed around the penis 2 to 3 cm distal to the newly created stoma, before the penis is transversely severed 1 to 2 cm distal to the ligature. The ligature used to compress the stump of the penis of this horse was a latex loop applied with a bander castration device, both of which are shown in Figure 61-25.
109
Figure 61-27. Rather than removing a triangle of tissue overlying the urethra, as is done when using the Vinsot technique of partial phallectomy, a permanent urethral stoma can be created more simply by making a 3- to 4-cm longitudinal incision into the catheterized urethral lumen. The margin of the urethra is sutured to the margin of the incision in the integument. These sutures should incorporate the corpus spongiosum penis. This stoma is being created proximal to the site of amputation and distal to the preputial orifice. A Babcock forceps grasps the urethral catheter.
110
describe the surgical modification of the Vinsot tx
horses were sedated, and the external portion of the penis and internal lamina of the prepuce were desensitized with a ring block administered proximal to the proposed site of urethrostomy. If the urethral stoma was to be created in the subischial region of the perineum, local anesthetic solution was instilled subcutaneously at the proposed site of incision. Rather than removing a triangle of tissue overlying the urethra, as is done when using the Vinsot technique of partial phallectomy, creating a permanent urethral stoma was simplified by making a 4-cm longitudinal incision into the catheterized urethral lumen (Figure 61-27). The stoma was created proximal to the site of amputation and distal to the preputial orifice if disease was confined to the free portion of the penis (i.e., that portion of the penis distal to the point of attachment of the internal lamina of the prepuce). The stoma was created in
the subischial region if the penis was to be amputated close to the preputial orifice. The incised edges of the urethra and the integument were apposed with simple-interrupted absorbable sutures that incorporated and compressed the cavernous tissue of the CSP. After creating the urethrostomy, the urethral catheter was removed, and a tourniquet was applied about 1 cm distal to the stoma using a bander castration device (see Figures 61-25 and 61-26). The penis was transected several centimeters distalto the tourniquet. The latex band and tissue distal to it detached between 3 and 4 weeks after surgery.
Partial phallectomy, when performed with the horse standing, can be further aided by desensitizing the penis and internal lamina of the prepuce via anesthesia of the pudendal nerves at the level of the ischial arch, as described earlier, instead of using a ring block (see “Visual Inspection,” earlier).
111
Disadvantages of the Vinsot tx
Primary disadvantages of the Vinsot technique of partial phallectomy, or its modifications, are the tendency of the urethra to stricture and the tendency for some horses to develop urine-induced contact dermatitis.
112
What are some diagnostic signs of urethral rents causing hematuria?
Terminal hematuria, dysuria, and visible urethral defects upon endoscopy.
113
What is the goal of surgical treatment for hematuria from urethral rents?
To eliminate bleeding and allow the rent to heal.
114
How does laser coagulation help in treating urethral rents?
By coagulating tissue around the rent, reducing bleeding.
115
Why may laser coagulation alone sometimes fail in treating hematuria?
Inadequate healing of the rent, possibly requiring additional corpus spongiotomy.
115
What is the expected outcome if inflammation is noted around a urethral defect?
Inflammation around urethral defects is usually not present with urethral rents.
116
What is dysuria, and when does it occur in horses with urethral rents?
Painful or difficult urination, seen at the end of urination.
117
What could explain higher CSP pressure in geldings compared to stallions?
Smaller cavernosal space volume in geldings.
118
What does a ring block anesthetize during the Vinsot technique?
The external portion of the penis and internal lamina of the prepuce.
118
What must be avoided when dissecting the cuff in segmental posthetomy?
Severing the large vessels near the tunica albuginea.
118
What is an indication for the Bolz technique combined with segmental posthetomy?
To retract a paralyzed penis with damaged prepuce into the preputial cavity.
118
What is a risk if the sutured end of a phallectomy stump is left too exposed?
Excessive hemorrhage and possible infection.
119
What is the Vinsot technique primarily used for in horses?
Partial phallectomy.
119
What is a potential complication of using a tightly fixed ligature on the penile stump?
Necrosis of adjacent tissue due to restricted blood flow.
120
Where is the urethral stoma created in the modified Vinsot technique?
Either distal to the preputial orifice or in the subischial region.
121
How long is the incision into the urethral lumen in the modified Vinsot technique?
4 cm.
122
What type of sutures are used to appose the urethra to the integument in the modified Vinsot technique?
Simple-interrupted absorbable sutures.
123
What main advantage does the Williams technique offer over the Vinsot technique?
Decreased likelihood of urethral stricture and contact dermatitis.
123
What device is used to apply a tourniquet during the Vinsot technique?
A bander castration device.
123
What is a common complication of the Vinsot technique?
Urethral stricture and urine-induced contact dermatitis.
124
What pattern of sutures is preferred in the Williams technique for compression?
Simple-continuous.
124
In the Williams technique, which direction does the triangle's apex face?
Proximally.
125
Why is the penis transected obliquely in the Williams technique?
To ensure the dorsum of the penile stump is longer than the ventrum.
126
What vessel branches are ligated during the Williams technique?
Large branches of the external pudendal vessels.
127
What is the final closure pattern for the stump in the Williams technique?
Sutures are placed through the urethra, tunica albuginea, and penile epithelium.
128
in the Scott technique, what guides the initial circumferential incision?
The intended site of transection.
129
How long is the urethral segment dissected free in the Scott technique?
4 to 5 cm.
130
How is the CCP stump closed in the Scott technique?
By apposing the tunica albuginea to the urethral groove.
131
What can be done with the urethral stump in the Scott technique?
It can be divided into triangular segments or folded over the penile end.
132
When is en bloc resection with penile retroversion recommended?
When the prepuce or penis has extensive neoplasia.
133
Where is the penis retroverted during en bloc resection with retroversion?
Through a subischial incision ventral to the anus.
134
What is the purpose of a Penrose drain in en bloc resection?
To manage fluid accumulation in deeper tissues.
135
How does en bloc resection without penile retroversion differ in positioning?
The penile stump is maintained in its normal ventral position.
136
What postoperative complication is common in partial phallectomy?
Hemorrhage from the urethral stoma.
137
What causes terminal hematuria after partial phallectomy?
Pressure imbalance between the urethra and CSP during urination.
138
What surgical procedure can address persistent hemorrhage at the stoma?
Corpus spongiotomy or urethrotomy.
139
How does corpus spongiotomy aid in healing the urethral stoma?
It decreases CSP pressure, diverting blood away from the stoma.
140
What postoperative complication can cause urinary obstruction?
Edema of the urethra.
141
How is the urethra identified during preoperative procedures?
By inserting a large-bore urethral catheter.
142
What is the purpose of the perineal incision in urethrotomy?
To prevent urine pocketing and facilitate healing.
143
What is a risk if the perineal incision is off midline?
Profuse hemorrhage from the external pudendal artery.
144
How long does urethrotomy typically take to heal?
Within 2 weeks.
145
What structure is often removed along with the penis in extensive en bloc resections?
Superficial inguinal lymph nodes.
146
How does the Williams technique differ in urethral incision from the Vinsot technique?
The Williams technique involves a triangle with a proximad apex.
147
What is a primary advantage of the Scott technique?
Precise division and suturing for better tissue integration.
148
What incision shape is used in en bloc resection with retroversion?
Fusiform around the preputial orifice.
149
Why is the urethra split along the midline in the Williams technique?
For apposition with the incised epithelial edge.
150
What factor contributes to penile stump dehiscence post-en bloc resection?
Excessive tension on skin sutures.
151
What happens to the latex band applied during the modified Vinsot technique?
It detaches with tissue between 3-4 weeks post-surgery.
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Maurer et al EVE 2022 What percentage of the equids in this study were geldings?
A) 21%
B) 57%
C) 79%
D) 85%
C) 79%
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Maurer et al EVE 2022 In what percentage of cases was partial phallectomy performed due to neoplastic growths?
A) 50%
B) 93%
C) 71%
D) 85%
B) 93%
154
Maurer et al EVE 2022 How many equids had a clinical diagnosis of squamous cell carcinoma (SCC)?
A) 5 out of 14
B) 8 out of 14
C) 11 out of 14
D) 13 out of 14
C) 11 out of 14
155
Maurer et al EVE 2022 What was the median age of equids diagnosed with SCC?
A) 14 years
B) 21 years
C) 22 years
D) 38 years
C) 22 years
156
Maurer et al EVE 2022 What percentage of cases experienced minor intraoperative complications, such as bleeding or neurological episodes?
A) 10%
B) 20%
C) 30%
D) 50%
B) 20%
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Maurer et al EVE 2022 What type of complications were observed in the immediate post-operative period for one of the animals?
A) Severe infection and blood loss
B) Haemorrhage with haematoma and oedema formation
C) Paralysis and excessive scarring
D) Loss of appetite and difficulty breathing
B) Haemorrhage with haematoma and oedema formation
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Figure 61-28. (A) Williams technique of phallectomy. A triangle is removed from the ventrum of the penis. The triangle’s apex is directed proximad. The urethra is split on its midline from the base to the apex of the triangle, and the edges of the urethra and the triangle’s epithelial edges are apposed with simple-interrupted absorbable sutures. (B) Before closing the stump, the transected edge of the corpus spongiosum penis at the base of the triangle can be compressed with a simple-continuous absorbable suture line through the urethral mucosa and tunica albuginea. (C) The stump is closed with interrupted sutures that pass through the urethra, the tunica albuginea of the urethral groove, and the tunica albuginea of the dorsum of the corpus cavernosum penis and the penile or preputial epithelium. The sutures should be preplaced at equidistant intervals for an even closure. (D) The sutures are tightened and tied, compressing the cavernous spaces, and the integument is apposed to the urethral mucosa.
159
Figure 61-29. Scott technique of phallectomy. (A) A circumferential transverse incision through the epithelium of the body of the penis or prepuce is made at the intended site of transection. Dissection is continued through the corpus cavernosum penis (CCP) to the urethral groove. The corpus spongiosum penis (CSP) is circumferentially incised to the urethra, and a 4- to 5-cm segment of urethra is dissected free from the amputated section of penis. (B) The stump of the CCP is closed by apposing the outer perimeter of its tunica albuginea to the tunica albuginea of the urethral groove with interrupted absorbable sutures preplaced at equidistant intervals. (C) The sinusoidal spaces of the CSP are closed by suturing the tunica albuginea surrounding the CSP to the submucosa of the urethra with interrupted or continuous absorbable sutures. (D) The urethral stump is stretched and folded back over the end of the penis, where it is sutured to the penile or preputial epithelium and underlying tunica albuginea.
160
Figure 61-30. En bloc resection of the penis. (A) Four centimeters of urethra is left beyond the penile stump. (B) The position of the penile stump when retroverted is demonstrated. (From Markel MD, Wheat JD, Jones K. Genital neoplasms treated by en bloc resection and penile retroversion in horses: 10 cases 1977–1986. J
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162
des
163
cribe the surgical removal of the free portion of the penis and prepuce by en bloc resection with retroversion
o remove the free portion of the penis and prepuce by en bloc resection, a fusiform incision is created around the preputial orifice. The incision begins about 6 cm cranial to the orifice and ends about 10 cm caudal to it. The incision is carried to the deep fascia of the abdominal tunic, and if neoplasia has metastasized to the superficial lymph nodes, dissection is extended through this plane to both superficial inguinal rings, and the superficial inguinal lymph nodes are removed. The penis is amputated 6 to 8 cm caudal to the fornix of the prepuce, and the amputated portion of the penis and the prepuce are removed en bloc. The penile shaft is amputated using a method similar to that described by Scott, leaving 4 cm of urethra protruding from the penile stump (Figure 61-30, A).
By bluntly separating penile fascia, the stump of the penis is retroverted through a 6-cm subischial incision created approximately 20 cm ventral to the anus, so that the distal end of the penile stump points caudad and extends just beyond the subischiaincision (see Figure 61-30, B). The tunica albuginea of the CCP and the fascia of the penis are sutured to the subcutaneous tissue of the subischial incision. The dorsal aspect of the protruding stump of the urethra is incised longitudinally over its 4-cm length, and the edges of the urethra are sutured to the surrounding edges of the incised subischial skin. Penrose drains are placed deeply at the cranial incision, if deemed necessary, and the subcutaneous tissue and skin are each closed separately (Figure 61-31). The technique can be modified by amputating the penis using the Williams or Vinsot technique of partial phallectomy, rather than the technique described by Scott incision (see Figure 61-30, B). The tunica albuginea of the CCP and the fascia of the penis are sutured to the subcutaneous tissue of the subischial incision. The dorsal aspect of the protruding stump of the urethra is incised longitudinally over its 4-cm length, and the edges of the urethra are sutured to the surrounding edges of the incised subischial skin.
164
describe Scott tx of partial phallectomy
With this technique, a circumferential transverse incision through the epithelium of the body of the penis or prepuce is made at the intended site of transection, and branches of the external pudendal vessels are ligated.99 Dissection is continued through the CCP to the urethral groove. The CSP is circumferentially incised to the urethra, which is easily identified by the urinary catheter in its lumen, and a 4- to 5-cm segment of urethra is dissected free from the amputated section of penis T
he stump of the CCP is closed by apposing the outer perimeter of its tunica albuginea to the tunica albuginea of the urethral groove with interrupted absorbable sutures preplaced at equidistant intervals (see Figure 61-29, B). The sinusoidal spaces of the CSP are closed by suturing the tunica albuginea surrounding the CSP to the submucosa of the urethra with interrupted or continuous absorbable sutures (see Figure 61-29, C). The urethral stump is divided into three equal triangular segments, with the apex of each triangle pointing distad. These segments are intermeshed with similarly prepared segments of penile or preputial integument and are apposed with simple-interrupted absorbable or nonabsorbable sutures. Sutures should include underlying tunica albuginea. Instead of dividing the urethral stump into three triangles, the urethral stump can be stretched and folded back over the end of the penis, where it is sutured to the penile or preputial epithelium and underlying tunica albuginea (see Figure 61-29, D).
165
describe en bloc resection without penile retroversion
With this technique, a fusiform incision is created on the midline beginning at the umbilicus. The incision extends caudad on each side of the preputial orifice and continues on the midline to a point 10 cm caudal to the preputial orifice. The caudal portion of the incision is extended and deepened to expose and remove the inguinal lymph nodes if neoplasia has metastasized to these structures.
Blunt dissection is continued into the loose areolar tissue of the prepuce, ligating large vessels as they are encountered.
After the shaft of the penis is exposed, dissection is redirected along the shaft of the penis in a plane superficial to the loose subcutaneous tissue overlying the vasculature of the penis. At least 10 cm of the shaft should be exposed. A tourniquet is applied around the shaft of the penis proximal to the site of amputation. The dorsal arteries and veins of the penis are ligated and transfixed to the tunica albuginea. The penis is transected caudal to the fornix of the prepuce using the method described by Williams.148 After the tourniquet is removed, the stump is fixed to the body wall on the midline with heavy absorbable interrupted sutures. The subcutaneous tissue cranial to the penile stump surrounding the exposed penile shaft is apposed. Skin is sutured to the tunica albuginea and the urethral mucosa of the new urethral orifice. The skin cranial and caudal to the urethral orifice is sutured.
This technique of en bloc resection requires a smaller incision and results in less alteration to the appearance of the horse than does the technique in which the penis is retroverted, while still allowing the surgeon to remove extensive portions of the penis and extirpate the regional lymph nodes.
