Chapter 65 - Kidneys and Ureters Flashcards
1
Q
What are the primary components of the equine urinary system?
A
Paired kidneys, ureters, bladder, and urethra.
2
Q
Where are the kidneys located in the horse?
A
In the retroperitoneal space.
3
Q
How much does the left kidney weigh in an adult horse?
A
800 to 1000 g.
4
Q
What anatomical feature makes the right kidney less accessible during rectal palpation?
A
Its cranial position and embedding in the liver.
5
Q
Describe the shape of the left kidney in horses.
A
Elongated, resembling a U or inverted J.
6
Q
How does the blood supply reach the kidneys?
A
Via one or more renal arteries branching from the aorta.
7
Q
What are accessory renal arteries, and where do they typically arise?
A
Additional arteries that may arise from the caudal mesenteric, testicular, ovarian, or deep circumflex iliac arteries.
8
Q
What characterizes the surface of each kidney?
A
It is covered by a fibrous capsule.
9
Q
What is found within the renal cortex of equine kidneys?
A
Renal corpuscles or glomeruli within Bowman capsules.
10
Q
How does the corticomedullary junction in horses differ from that in other species?
A
It is less distinct and typically a deep red color.
11
Q
What anatomical structure defines the renal columns?
A
Cortical projections that surround the convex base of renal pyramids.
12
Q
How many lobes are typically found in equine kidneys?
A
40 to 60 lobes.
13
Q
What is the significance of the renal pyramids in horses?
A
They are largely fused, with some separation at the apices by connective tissue.
14
Q
What is the structure and function of the renal pelvis?
A
A funnel-shaped structure that collects urine before it enters the ureter, consisting of three layers.
15
Q
What are the layers of the renal pelvis?
A
An external fibrous coat, an intermediate smooth muscle layer, and an innermost layer of transitional epithelium.
16
Q
What are terminal recesses in equine kidneys?
A
Narrow tubular structures that extend into the poles of the kidneys, connecting to the renal pelvis.
17
Q
What role does the renal crest play in the kidney?
A
It is a fusion of the apices of many pyramids and aids in directing urine flow into the renal pelvis.
18
Q
How do the ureters prevent vesicoureteral reflux?
A
The intramural segment of the ureters functions as a one-way valve.
19
Q
What is the diameter range of ureters in horses?
A
6 to 8 mm
20
Q
How long are the ureters in horses?
A
Approximately 70 cm
21
Q
What observable phenomenon occurs during cystoscopy in horses?
A
Streams of urine intermittently exiting each ureter.
22
Q
What histological components make up the nephron?
A
Renal corpuscle, proximal tubule, intermediate tubule (loop of Henle), distal convoluted tubule, connecting tubule, and collecting ducts.
23
Q
How many glomeruli are found in the equine left kidney?
A
Approximately 10 million.
24
Q
What histological feature of equine nephrons is larger compared to other species?
A
The diameter and epithelial height of the collecting duct segments.
25
What autonomic nerve types primarily innervate the kidneys?
Predominantly sympathetic nerves.
26
What is the effect of low-frequency stimulation of renal nerves?
Increases proximal tubular sodium reabsorption and renin release.
27
How does dopamine affect renal blood flow?
Activation of DA-1 receptors increases perfusion of the outer renal medulla.
28
What unintended effect can occur from administering α2-agonists like xylazine?
Induction of diuresis.
29
What role does autonomic innervation play in ureteral function?
It regulates ureteral peristalsis.
30
What adrenergic receptors are found in equine ureteral smooth muscle?
Both α1- and β2-adrenoceptors.
31
What is the functional role of α1-adrenoceptors in the ureters?
Induce contraction of ureteral smooth muscle.
32
What happens in the renal pelvis that initiates ureteral peristalsis?
Pacemaker activity.
33
What unique characteristic is associated with the density of adrenergic neurons in the ureters?
Greater densities in the proximal and intravesicular portions.
34
What is the primary function of the collecting ducts in the kidney?
To transport urine from nephrons to the renal pelvis.
35
What are the implications of histologic differences in equine kidneys compared to other mammals?
Potential functional differences that have yet to be investigated.
36
α1- and β2-adrenoceptors, which induce
contraction and relaxation,
37
The equine ureteral smooth muscle contains both α1- and β2-adrenoceptors are activated by
norepinephrine
38
Figure 65-2. Endoscopic image of a left ectopic ureter (LEU) opening into the urethral wall (U) of a filly. (From Cokelaere SM, Martens A, Vanschandevijl K, et al. Hand-assisted laparoscopic nephrectomy after initial ureterocystostomy in a Shire filly with left ureteral ectopia
39
Figure 65-3. (A) Ventrodorsal radiographic view of a retrograde contrast-enhanced urethrocystogram in a colt with bilateral ectopic ureters showing the bladder (a), pelvic urethra (b), and coxofemoral joint (c). The lower straight white arrow indicates a catheter within the penile urethra and the uppermost white arrows indicate the ureters. (
40
Figure 65-3. (A) Ventrodorsal radiographic view of a retrograde contrast-enhanced urethrocystogram in a colt with bilateral ectopic ureters showing the bladder (a), pelvic urethra (b), and coxofemoral joint (c). The lower straight white arrow indicates a catheter within the penile urethra and the uppermost white arrows indicate the ureters. (B) Ventrodorsal radiographic view of a percutaneous ultrasound-guided pyelogram in a filly with a left ectopic ureter detailing both hydronephrosis and a markedly enlarged and tortuous ureter. Although both approaches provide greater contrast detail than intravenous pyelography, insertion of the distal ends of the ectopic ureters is not well detailed in either study. (A, From Modransky PD, Wagner PC, Robinette JD, et al. Surgical correction of bilateral ectopic ureters in two foals. Vet Surg 1983;12:141. B, From Tomlinson JE, Farnsworth K, Sage AM, et al. Percutaneous ultrasound-guided pyelography aided diagnosis of ectopic ureter and hydronephrosis in a 3-week-old filly. Vet Radiol Ultrasound 2001;42:349, with permission.)
40
Figure 65-4. (A) Kidney and ureter removed from a Standardbred colt with a proximal ureteral defect (or tear) through which a probe is inserted.
41
Figure 65-4. (A) Kidney and ureter removed from a Standardbred colt with a proximal ureteral defect (or tear) through which a probe is inserted. (B) Thoracic wall from the same foal showing a series of five fractured ribs, providing support that ureteral defects in foals can be acquired secondary to trauma.
42
Figure 65-5. Ultrasonographic images of the right kidney of a horse with renal adenocarcinoma.
(A) Little evidence of normal renal architecture remains. (B) Multiple areas of hypoechoic fluid are apparent within the kidney.
43
What are the two main categories of disorders that may require surgery in the equine urinary system?
Congenital anomalies and acquired disorders.
44
List the congenital anomalies that can be found in the equine urinary tract
ectopic ureter
ureteral defects or tears (ureterorrhexis)
vascular anomalies
45
What is the most common congenital anomaly of the equine urinary tract?
Ectopic ureter.
46
What happens when the ureteric bud fails to incorporate into the urogenital sinus?
Ectopic ureters open near the urethral papilla in females or in the pelvic urethra in males.
47
How can ectopic ureters present clinically in foals?
Urinary incontinence, often noticed as scalding of the hind limbs.
48
What is a significant complication of unilateral ectopic ureters?
The foal may urinate normally if the other ureter is functioning.
49
Which imaging technique is preferred for locating ectopic ureter openings?
Endoscopy.
50
Why might intravenous contrast excretory urography be inconclusive in diagnosing ectopic ureters?
Limited detail in visualizing the ureteral course.
51
What is the surgical treatment for ectopic ureters?
Ureterocystotomy or unilateral nephrectomy.
52
What preoperative assessments are crucial before surgical intervention for ectopic ureters?
Determining whether the condition is unilateral or bilateral and assessing urinary tract infection status.
53
What does a successful surgical outcome for ectopic ureter require in terms of bladder function?
Normal detrusor and urethral sphincter function.
54
What anatomical abnormalities were found in foals with ureteral defects?
Proximal ureteral defects near the kidney.
55
What clinical signs are associated with ureteral defects or tears?
Decreased nursing, lethargy, abdominal distention, diarrhea, and muscle twitching.
56
How can ultrasonography assist in diagnosing ureteral defects?
it can reveal dilation of the renal pelvis and affected ureter, as well as fluid accumulation.
57
What is the recommended imaging procedure when a ureteral defect is suspected?
CT imaging after intravenous contrast administration.
58
What common complication may arise post-surgery in foals with ureteral defects?
Ascending urinary tract infection (UTI).
59
What rare vascular anomalies may affect the equine urinary tract?
Renal arteriovenous malformations
distal aortic aneurysms.
60
What is a potential consequence of renal vascular malformations in horses?
Hematuria or hemoglobinuria.
61
Which breed of horses is mentioned as being at greater risk for ectopic ureters?
Quarter Horses and Standardbreds.
62
What complication can arise from ureteral tears following blunt trauma?
Retroperitoneal accumulation of urine or uroperitoneum.
63
What diagnostic procedure can be used to localize ureteral defects during surgery?
Catheterization of the ureters with methylene blue injection.
64
What characterizes the anatomical structure of the ectopic ureter?
It may be markedly dilated and tortuous.
65
How is hematuria evaluated in the context of vascular anomalies?
Ultrasonography, contrast studies, or cystoscopy to determine the source.
66
What clinical outcomes were reported following nephrectomy in ectopic ureter cases?
Favorable outcomes in most cases, though some complications occurred.
66
What is the risk associated with a unilateral defect in the presence of hematuria?
Potential fatal exsanguination through the urinary tract.
67
What anatomical features are typically observed in foals with ureteral defects?
Distended, tortuous ureters and possibly hydronephrosis.
68
What surgical options exist for treating ureteral defects?
Suturing the defect or nephrectomy.
69
What is the typical age range for foals presenting with symptoms of ureteral defects?
Symptoms may appear 4–16 days after birth.
70
What imaging techniques may provide limited information about ectopic ureters?
Intravenous pyelography and traditional contrast studies.
71
What method is used to assess urinary tract function in horses with ectopic ureters?
Cystometrography.
72
What anatomical relationship between the ureter and kidney is often compromised in ectopic cases?
The appropriate location and function of the ureteral opening into the bladder.
73
How can surgical intervention impact long-term function in cases of ectopic ureters?
Persistence of incontinence may occur postoperatively.
74
What was noted about the sex distribution of ectopic ureter cases in horses?
A predominance of females, likely due to easier recognition of symptoms.
75
What can complicate the surgical repair of ureteral defects in foals?
The presence of multiple defects and possible renal dysfunction.
76
What do vascular anomalies in the urinary tract of horses potentially lead to?
Life-threatening hemorrhage requiring urgent surgical intervention.
77
What complications were noted in cases treated by ureterocystotomy?
Some horses developed postoperative complications leading to death.
78
What are the typical outcomes following surgical correction of ectopic ureters?
Varying success rates, with nephrectomy showing more favorable results.
79
What factors complicate the assessment and surgical management of ectopic ureters in horses?
The potential for urinary tract anomalies and the condition's bilateral nature.
80
What is the prevalence range of urolithiasis in horses?
Prevalence ranges from 0.11% to 0.7%.
81
What types of crystals are commonly involved in nephrolithiasis?
Calcium carbonate and calcium oxalate crystals.
81
What may initiate the formation of a nidus for nephroliths?
Various diseases that damage renal parenchyma.
82
How do nephroliths in horses differ from those in humans?
It is unclear if they develop spontaneously in horses as they do in humans.
83
What medication class is speculated to increase nephrolith formation in horses?
Nonsteroidal anti-inflammatory drugs (NSAIDs).
84
How do horses typically present when suffering from nephrolithiasis?
Often asymptomatic; signs appear if obstructive disease develops.
85
What clinical signs indicate obstructive disease in horses?
Colic, stranguria, and hematuria.
86
What is the diagnostic method most commonly used for renal and ureteral calculi?
Rectal or ultrasonographic examination.
87
What can ultrasonography reveal about renal calculi?
Presence, number, and location of calculi.
88
What finding is often associated with long-standing upper tract obstructive lithiasis?
Hydronephrosis.
89
What is the significance of azotemia in diagnosing renal disease in horses?
It indicates bilateral disease; unilateral disease may maintain function.
90
What is the recommended treatment for unilateral obstructive nephrolithiasis without azotemia?
Surgical removal of the affected kidney (nephrectomy).
91
What are common isolates in horses with septic nephritis?
Actinobacillus equuli, Streptococcus equi, Rhodococcus equi, Salmonella spp.
92
What is the primary reason for the rarity of upper UTIs in horses?
The anatomical barrier of the ureters prevents vesicoureteral reflux.
93
What condition may lead to pyelonephritis due to increased risk for VUR?
Ectopic ureter or bladder distention.
94
What are the clinical signs of pyelonephritis in horses?
Hematuria, pyuria, fever, weight loss, anorexia, lethargy.
95
What is the most common renal tumor in horses?
Renal cell carcinoma (adenocarcinoma).
95
Which diagnostic tests are crucial for evaluating upper UTIs?
Physical exam, urinalysis, quantitative urine culture.
96
What nonspecific symptoms are associated with renal neoplasia in horses?
Poor performance, lethargy, weight loss, recurrent colic.
97
What percentage of horses with renal cell carcinoma present with hematuria?
94%.
98
What outcome is common after nephrectomy for renal cell carcinoma?
High likelihood of euthanasia due to metastases.
99
What often complicates the surgical removal of renal tumors in horses?
Tumors are typically too large and adherent to surrounding organs.
100
What is the primary complication that arises during surgery for renal tumors?
Uncontrollable intraoperative hemorrhage.
101
Which tumor arises from primitive nephrogenic tissue?
Nephroblastoma (Wilms tumor).
102
What is a characteristic of transitional cell carcinoma in horses?
It can affect the upper urinary tract.
103
What condition can result from mucinous hyperplasia in the renal pelvis?
Ureteral obstruction and hydronephrosis.
104
How is ureterorrhexis typically diagnosed in horses?
Often during exploratory celiotomy or imaging.
104
What is a rare cause of ureteral disruption in adult horses?
Trauma, such as during dystocia or falls.
105
What are the clinical signs of ureteral disruption?
Abdominal distention, colic signs, and uroabdomen.
106
What treatment was applied in the mare with ureteral disruption?
Placement of a ureteral stent.
107
What is the prognosis for horses with renal neoplasia?
Generally poor due to advanced disease at diagnosis.
108
Which clinical sign is a strong indicator of upper urinary tract disease?
Detection of a palpable mass during rectal examination.
109
What may accompany nephrolithiasis and complicate diagnosis?
Concurrent upper UTIs.
109
What is one way to confirm unilateral vs. bilateral upper UTI?
Ureteral catheterization for urine sample collection.
110
What does the presence of hydronephrosis indicate in a horse?
Possible obstructive disease affecting kidney function.
111
Nephroblastoma (Wilms tumor) is an
embryonal tumor that arises in primitive nephrogenic tissue or in foci of dysplastic renal tissue; the latter tumor types arise from the uroepithelium of the renal pelvis or ureter
111
How does renal adenoma typically present in horses?
As incidental necropsy findings, usually asymptomatic.
112
What is a potential complication of bladder distention in horses?
Increased risk of vesicoureteral reflux leading to pyelonephritis.
113
What imaging technique is commonly used to guide a percutaneous renal biopsy?
Ultrasonography.
113
What might be an effective treatment option for obstructive unilateral renal calculi?
Nephrectomy, if there is no azotemia.
114
What is the most common complication after a renal biopsy?
Microscopic hematuria.
115
What percentage of patients experience gross hematuria after renal biopsy?
Less than 10%.
116
What type of biopsy instrument is often used in equine renal biopsies?
A Tru-cut biopsy needle or a spring-loaded biopsy device.
116
In horses, which kidney is typically biopsied when bilateral disease is suspected?
The right kidney.
117
What type of renal disease is more common in horses compared to humans?
Tubulointerstitial renal disease.
118
What two conditions can a renal biopsy help distinguish in horses?
Renal dysplasia and neoplasia versus infection.
118
What is a potential consequence of a blood clot in the bladder following a renal biopsy?
Urethral obstruction
119
What is the recommended monitoring period after a renal biopsy?
1 to 3 days.
120
What percentage of horses experienced colic as a complication post-biopsy?
4%.
121
What type of microscopic examinations can be performed on biopsy samples?
Immunohistochemistry or electron microscopy.
122
What is the primary risk associated with renal biopsy in horses?
Hemorrhage.
123
How is the biopsy needle typically angled in equine procedures?
Perpendicular to the kidney.
124
What is one method of assessing for complications post-biopsy?
Monitoring for changes in hematuria or signs of hemorrhage.
125
What is the primary approach for unilateral right nephrectomy in horses?
A right 17th rib resection or through the 16th and 15th intercostal spaces.
126
What is the major complication associated with entering the thoracic cavity during nephrectomy?
Increased risk of pneumothorax.
127
What is the skin incision length for a transcostal nephrectomy?
30 to 40 cm
128
Which muscles must be dissected to expose the rib during a nephrectomy?
The serratus dorsalis caudalis and external abdominal oblique muscles.
129
How is the rib transected during nephrectomy?
Using a bone saw or Gigli wire, 2 to 5 cm distal to the costovertebral articulation.
130
What instruments are used to smooth the end of the rib after transection?
Rongeurs and a bone rasp.
131
What technique is employed to ligate the ureterovascular pedicle?
Individual double ligation of the renal artery, vein, and ureter.
132
What type of drain is used after kidney resection?
Either a Penrose drain or a closed suction drain.
133
What surgical technique is described for unilateral left nephrectomy?
Similar to the right, using either a 17th or 18th rib resection or a dorsal flank incision.
134
What is the primary focus of the ventral midline approach during nephrectomy?
Creating a median celiotomy extending from caudal to the umbilicus.
135
How is the ascending colon managed during a ventral midline nephrectomy?
By performing a pelvic flexure enterotomy and protecting it with a plastic bag.
136
What is done to minimize renal congestion during nephrectomy?
The renal artery is ligated first.
137
What is the significance of using hemostatic clips or staples during nephrectomy?
They facilitate kidney removal and secure major vascular elements.
138
How is laparoscopic nephrectomy approached in horses?
Using an ipsilateral flank approach with multiple portals for instrumentation.
139
What is the purpose of injecting epinephrine before laparoscopic nephrectomy?
To create splenic contraction and enlarge the surgical workspace.
140
What is a common complication of laparoscopic nephrectomy?
Pneumothorax and bleeding from accessory renal arteries.
141
How many portals are typically created for laparoscopic nephrectomy?
At least three portals.
142
What is the length of the perirenal incision made during laparoscopic nephrectomy?
10 to 15 cm.
142
Why is the renal artery ligated before the renal vein during surgery?
To reduce the risk of renal congestion.
143
How is the perirenal peritoneum prepared for dissection in laparoscopic nephrectomy?
Injected with local anesthetic and incised using endoscopic scissors.
144
How can hydronephrotic kidneys be managed before removal?
Decompression using a tip suction cannula.
145
What is the benefit of hand-assisted laparoscopic nephrectomy?
It allows tactile sensation, reduces surgical time, and lessens morbidity.
146
How many neprectomy approach do you know?
3 TECHNIQUES:
1) transcostal approach
2) ventral midline approach
3) laparoscopic hand assisted approach
147
describe transcostal nephrectomy approach
GA - LR -Positive pressure ventilation should be available in case the thoracic cavity is entered inadvertently. This complication occurs more commonly on the right side of the horse.103 A 30- to 40-cm skin incision is made over the 16th or 17th rib. Dissection is continued through the serratus dorsalis caudalis and external abdominal oblique muscles to expose the periosteum of the rib. The periosteum is incised and elevated around the rib, taking care to avoid injury to the intercostal vasculature. A Doyen rib raspatory is helpful for this dissection (see Figure 49-11). The rib is transected 2 to 5 cm distal to the costovertebral articulation using a bone saw or Gigli wire (Figure 65-6). Ventrally, the rib is disarticulated at the costochondral junction. Rongeurs and a bone rasp should be used to smooth the end of the bone at the proximal extent of the incision. The medial costal periosteum is longitudinally incised, and the kidney is exposed by blunt dissection through the retroperitoneal fat. If additional exposure is required, the incision can be extended ventrad.
The kidney is mobilized by digital circumferential dissection through perinephric fat to expose the ureterovascular pedicle and penetrating capsular vessels (Figure 65-7). A self-retaining retractor is helpful to aid in exposing the kidney. Small capsular vessels and accessory renal arteries should be ligated. Electrocautery or vessel-sealing devices can be used if appropriate for the size of the vessel. The ureterovascular pedicle is isolated, and the artery, vein, and ureter are individually double-ligated (Figure 65-8). The use of hemostatic vascular clips or vascular staples facilitates removal of the kidney and provides adequate access for suture ligation of major vascular elements.
After removal of the affected kidney, the renal fossa is lavaged and again evaluated for evidence of hemorrhage. The ureter is mobilized, ligated as far distad as possible, and transected. Resection of the pelvic ureter is not possible when using a flank approach for nephrectomy. Either Penrose or closed suction drains are placed after resection of the kidney to evacuate blood accumulating in the dead space or to manage urine-contaminated tissues.
The periosteum of the rib and deep fascia are closed with a synthetic absorbable suture material placed in a simple-interrupted or simple-continuous pattern. The subcutaneous tissues and skin are closed routinely. Unilateral left nephrectomy of the horse is performed in similar fashion using either a 17th or 18th rib resection or a dorsal flank incision.
148
Figure 65-6. Resection of the 17th rib permits surgical access for right nephrectomy or nephrotomy procedure.
149
describe the ventral midline nephrectomy approach
In the ventral midline approach, a median celiotomy is created extending from just caudal to the umbilicus cranially. The ascending colon can be evacuated via a pelvic flexure enterotomy and is protected in a plastic bag on top of the thorax to improve exposure. The small intestine is reflected toward the diaphragm within the abdomen using moist laparotomy sponges. The peritoneum over the affected kidney is grasped with Brown-Addson forceps and incised from the cranial to the caudal pole of the kidney using Metzenbaum scissors. Blunt dissection is then used to mobilize the kidney from the retroperitoneal fat. The renal artery, vein, and ureter are individually isolated and triple-ligated. The renal artery is ligated first to reduce renal congestion. Scissors or the LigaSure device are used to transect the renal pedicle. After removal of the kidney, the peritoneal incision made to expose the kidney is left unsutured, the intestine is repositioned within the abdomen and routine closure of the abdomen is performed.
149
Figure 65-8. The renal artery, vein, and ureter are ligated with transfixing ligatures before resection and removal of the kidney.
150
Figure 65-7. All perirenal fat is removed by blunt dissection to permit access to the ureterovascular pedicle.
151
describe the portal sites in the laparoscopic nephrectomy
The first portal is made between the 17th and 18th ribs at the ventral border of the tuber coxae. The second portal is located midway between the last rib and the dorsocranial border of the tuber coxae. The third portal is prepared approximately 8 cm (3 in) ventral to the second portal. A 30-cm (12-in) long, 10-mm (4-in) diameter, 0-degree laparoscope is used.
151
In the laparoscopic assisted nephrectomy you start with injection of epinephrine (1mg in 10 ml nacl) why?
The procedure for removing the left kidney starts with injection of epinephrine (1 mg in 10 mLof saline) in three or four sites at the dorsal border of the spleen to create splenic contraction. This enlarges the space in which the surgeon has to work. The perirenal fascia is injected dorsally with 20 mL of 2% mepivacaine hydrochloride
152
describe the surgical tx of laparoroscopy for nephrectomy
The first portal is made between the 17th and 18th ribs at the ventral border of the tuber coxae. The second portal is located midway between the last rib and the dorsocranial border of the tuber coxae. The third portal is prepared approximately 8 cm (3 in) ventral to the second portal. A 30-cm (12-in) long, 10-mm (4-in) diameter, 0-degree laparoscope is used. The procedure for removing the left kidney starts with injection of epinephrine (1 mg in 10 mLof saline) in three or four sites at the dorsal border of the spleen to create splenic contraction. This enlarges the space in which the surgeon has to work. The perirenal fascia is injected dorsally with 20 mL of 2% mepivacaine hydrochloride This enlarges the space in which the surgeon has to work. The perirenal fascia is injected dorsally with 20 mL of 2% mepivacaine hydrochloride. A monopolar electrocautery hook blade is used to create a plane of dissection dorsal to the kidney. Perirenal fat is dissected and removed with curved laparoscopic scissors. The hilus of the kidney is carefully dissected free to identify the vessels. Specialized (clockwise and counterclockwise) laparoscopic ligation instruments are used to ligate the renal artery, vein, and ureter, in that order. These instruments are curved half-circle at the end and are used to pass a suture around the vasculature and ureter. The area is assessed for hemorrhage prior to making a small flank incision to retrieve the kidney
153
what are the complications of laparoscopic nephrectomy?
Complications include pneumothorax and bleeding from accessory renal arteries
154
describe hand assisted laparoscopy in horses
The paralumbar fossa and thoracic wall corresponding to the kidney that is to be removed is clipped and surgically prepared for aseptic surgery. The paralumbar fossa and 17th intercostal space are desensitized by local infiltration with mepivacaine hydrochloride. A laparoscopic portal is created in the 17th intercostal space at the level of the ventral border of the tuber coxae and an instrument portal at the same level 2 to 3 cm caudal to the last rib and a 30-degree laparoscope is inserted. A capnoperitoneum is induced by insufflation through the cannula. A laparoscopic needle is used to infiltrate the perirenal peritoneum and retroperitoneal region with 20 mL of 2% lidocaine or mepivacaine hydrochloride. After a few minutes, the perirenal peritoneum is incised horizontally for a length of 10 to 15 cm using endoscopic scissors. On the left side, this incision starts at the caudal edge of the nephrosplenic ligament and extends in a cranial direction. On the right side, this incision is located dorsal to the cecal base, specifically 10 cm dorsal to the duodenal mesenteric vessels. For the hand-assisted part, a modified grip approach is used to create a 10- to 15-cm-long mini-laparotomy 5 cm caudal to the instrument portal and centered at the level of the ventral border of the tuber coxae in the paralumbar fossa. The perirenal incision is enlarged digitally under laparoscopic observation. The perirenal fat is bluntly dissected to mobilize the kidney. The laparoscope is then introduced in the retroperitoneal space to visualize and palpate the renal vessels and ureter. The renal artery can have multiple branches close to the hilus. Individual vessels are separated manually or using instruments and ligated using size USP 1 or 2 braided lactomer suture. To avoid renal congestion, the arterial vessels are ligated first. The first two ligatures are placed close to the aorta and a third ligature is placed close to the hilus. This method of ligation is used for the renal vein and ureter as well. Smaller accessory vessels can be coagulated laparoscopically using a vessel-sealing device. The vessels and ureter are transected between the second and third ligature and checked laparoscopically for hemorrhage. Using grasping forceps, the kidney is exteriorized through the laparotomy that is enlarged as needed.
Hydronephrotic kidneys can be decompressed intraabdominally using a tip suction cannula before exteriorization. Routine closure of the mini-laparotomy and portals is performed
155
the most immediate severe complication of hand assisted nephrectomy is
torn acessory branch of renal artery
156
157
What anatomical structures are critical to ligate during nephrectomy?
The renal artery, renal vein, and ureter.
158
What surgical preparation is done for the horse prior to nephrectomy?
Feeding only mash and pellets, with free access to water for 48 hours.
159
What does the incision over the 16th or 17th rib allow access to?
The kidney and surrounding retroperitoneal structures.
160
Why is nephrotomy performed less frequently in horses compared to nephrectomy?
Indications for nephrotomy are fewer and the technical difficulty is greater.
161
What is the primary indication for performing a nephrotomy?
removal of renal calculi.
162
What is a significant challenge during nephrotomy surgery?
Difficulty in visibility and managing hemorrhage from penetrating capsular vessels.
163
What is the purpose of occluding major renal vessels during nephrotomy?
To prevent excessive bleeding before incising the renal cortex.
164
how is the renal collecting system accessed during nephrotomy?
By extending the renal incision to expose the collecting system and renal pelvis.
165
What is the primary indication for ureterotomy in horses?
Obstructive urolithiasis.
166
Why is presentation of uncomplicated ureteral calculi in horses rare?
Horses are often chronically affected and may show no symptoms until necropsy.
167
What surgical approach is typically used to explore ureteral pathology in horses?
Flank laparotomy or caudal ventral midline laparotomy.
168
How is the ureter repaired after urolith removal?
Closed in a simple-continuous pattern with synthetic absorbable sutures.
169
What technique can facilitate the closed dislodgment of a ureterolith?
The use of a Dormia Stone Dislodger.
170
What is the function of the stent used in ureteral repair?
To maintain patency of the ureter during healing.
171
How was a traumatic ureteral tear in a postpartum mare repaired?
Using an indwelling polyethylene tubing stent and videoendoscopic guidance.
172
What complications can arise from a ureteral defect in neonates?
Development of uroperitoneum and retroperitoneal urine accumulation.
173
What surgical technique is used for managing ectopic ureters in horses?
Neoureterostomy.
174
What incision is made for a neoureterostomy procedure?
A caudoventral midline incision extended to the pubis.
175
What is the purpose of retrograde catheterization in identifying an ectopic ureter?
To locate the ectopic ureter for surgical intervention.
176
What suture technique is ideal for apposing ureteral and vesicular mucosa?
Using USP size 3-0 or 4-0 synthetic absorbable sutures.
177
How should post-operative hydration be managed after renal surgery?
With intravenous fluids and monitoring of urine production.
178
What common electrolyte imbalances should be monitored after nephrectomy?
Potassium levels may show transient imbalance.
179
Why are prophylactic antibiotics indicated during renal surgery?
Because it is a clean-contaminated surgery.
180
What should be done if septic conditions are encountered during surgery?
Antibiotic therapy should be guided by intraoperative culture results.
181
What should be done to repair a diaphragm defect caused during a flank approach?
Suturing the defect to the adjacent costal musculature.
182
Why is the use of a grasping basket beneficial for ureteroliths?
It allows for non-invasive dislodgment of ureteral stones.
183
What anatomical structure is typically involved in ureterotomy procedures?
The ureter, particularly lesions located in its proximal third.
184
What materials are used for ureteral stenting in surgical repairs?
Polyethylene tubing or similar synthetic materials.
185
What anatomical challenges complicate ureterotomy in horses?
Limited exposure and the position of lesions in the ureter.
186
What condition can arise from a defect in the ureter leading to urine leakage?
Uroperitoneum.
187
What is the importance of monitoring serum electrolyte levels post-surgery?
To identify and manage potential imbalances affecting renal function.
188
Figure 65-9. Ligatures are placed to secure a ureter (arrow) after translocation to the bladder from an ectopic site. The ureter has been tunneled through the seromuscular layer of the bladder to prevent vesicoureteral reflux.
189
Figure 65-10. Endoscopic appearance of the ureterovesicular anastomosis demonstrated in Figure 65-9. The ureteral stoma can be observed on the dorsolateral wall of the bladder (arrow).
