Surgery Flashcards
Know the basic anatomy of the kidney, and where they are positioned within the abdomen ?
Anatomy of kidney
- 1-13
Position of kidney within the abdomen
- Located within the retroperitoneal space
- cranial pole of right kidney in the caudate lobe of the liver attahed by the hepatorenal ligament.
- The left kidney is more caudal and mobile.
Describe the aetiology and pathology of common renal disease ?
Renal disease
Renal neoplasia
- cat usually lymphoma
- dog usually renal cell carcinoma
- majority are malignant
Prognosis
- 16 months carcinoma
- 9 months sarcoma
- affected via mitotic index, vascular invasion and COX2 expression
Acquired renal cyst
- these cyst are usually epithelial lined
- may be secondary to nephropathy
- alcohol infusion
Perirenal pseudocyst
- unilateral or bilateral fluid accumulation
- modified transudate
- if drained this cyst type will recur
- must surgicall remove cyst
- renal failure could potentially still progress
Describe the indications for nephrectomy ?
The indications for nephrectomy
- Unresponsive pyelonephritis (kidney infection)
- perinephric abscesses or cyst (pernephric space includes ureters, adrenal glands and fat)
- Unilateral renal neoplasia
- severe renal trauma
- uretal conditions that result in hydronephrosis
Know the clinical signs and biochemical changes associated with renal diseases of the kidney ?
Clinical signs of various renal diseases of the kidney.
Renal neoplasia
- pyuria (WBC in urine)
- haematuria
- proteinuria
- palpable mass + weight loss
- polycythemia
- isothenuria (specific gravity = plasma)
Renal calculi
- non specific
- - vomiting, lethargy and anorexia
- radiopaque calculi
Trauma
- elevated BUN,
- elevated creatine
- increase in urine specific gravity
Know the diagnostic modalties available to investigate renal disease ?
Imaging modalities of the kidney
Radiology
- dog 2-2.5x adjacent vertebrae
- cat 2-3x adjacent vertebrae
Intravenous pyelogram
- 20-40mins until excretory phase
Ultrasound
- detect focal, multifocal and parenchymal disease
- poor for parenchymal disease
- renal pelvis dilation
- pyelonephritis
- ultrasound guided biopsy
- Doppler
CT
MRI
Scintigraphy
- small amount radioactive material swallowed or injected
Describe the surgical technique of nephrectomy / Ureteronephrectomy ?
The surgical technique of nephrectomy.
(Surgical removal of the kidney)
Ureteronephrectomy - removal of kidney + unilateral ureter
- pre op care (mannitol, dopamine)
- surgical prep
- Prior to surgery ensure the remaining kidney is functional via glomerula filtration rate (GFR)
- The risk of leaving the kidney in place must be greater than its removal.
Surgical technique
- midline coliotomy
- grasp peritoneum over the kidney and incise
- elevate and retract medially to locate renal artery
- there can be two renal arteries and both require ligation
- gentle tissue handling
- +/_ remove ipsilateral ureter
left ovarian artery drains into renal vein diseased kidneys have increased renal capsular blood flow
Show an understanding of specific renal diseases and surgical treatment options available
Diseases of the kidney and their potential treatment
Renal neoplasia bilateral - paliative care
renal neoplasia unilateral - nephrectomy
hydronephrosis - nephrectomy / ureteronephrectomy
acquired renal cyst infusion with alcohol
perineal cyst - surgical removal through nephrectomy
renal stones - nphrotomy
Describe the surgical technique of a nephrotomy ?
Nephrotomy
(nephromtomy is usually carried out to remove calculi lodged in the renal pelvis).
- avoid hydronephrosis (not enough parenchyma to close).
- if bilateral carry out procedure 4-5 weeks apart (bilateral nephropathies may precipiate renal failure)
- may temporarily reduce renal function 25-50% due to occulsion of renal vessels
- mobilise kidney exposing the convex surface - blunt disect through kidney parenchyma
- remove calculi and flush
- assess ureter for patency
CLOSE horizontal mattress sutures
Identify this instrument ?
Balfour retractors
Describe an exploratory laporarotomy and the use of Balfour retractors ?
Exploratory laparotomy - systemic abdominal exploration
- incision xyphiod to pubis (in male dogs make a lateral incision around the prepuce
- be systematic, view every organ in the same order every time
- BRANCH OF SUPERFICIAL EPIGASTRIC WILL BE TRANSECTED
- REMOVE FALCIFORM LIGAMENT
- place balfour retractors to hold abdomen open
- keep moist
- blunt dissect soft tissues
- assess the quantity and quality of abdominal fluid collect fluid for culture if concerned).
Use the mesocolon and mesoduodenum to assess gutters
Three layer closure
- linea alba
- subcutaneous tissue
- skin
(do not include the peritoneum).
Describe preoperative and postoperative management for nephromtomy / nephrectomy ?
Kidney surgery pre and post operative management
Pre operative management
- analgesics
- monitoring - vital signs, fluid balance, wound care
- haemorrhage control
- addressing urinary incontenance
- measure 20-45ml/kg urine production a day = 1-2ml an hour + should be turbid
- blood pressure monitoring 70mmHg
Manitol = increase intrvascular volume + tubular flow rate
Dopamine = increase GFR
Demonstrate knowledge of the mesenteric baskets ?
Mesenteric baskets
Discuss a minimum database required for a particular patient ?
Describe the vasculature of the kidneys ?
Vasculature of the kidneys
Arteries and veins
- renal artery from the aorta
- segmental 3-7 interlobular
- renal artery
- interlobular arteries
- arcuate arteries
Lymphatics via the hilus
sympathetic and parasympathetic nervous supply (vagal trunk).
Know the anatomy of the ureters ?
Anatomy of the ureter
- paired fibromuscular tubes
- contained within the retroperitoneal space
- ventral to psoas major and minor muscles
- ureters can be circumcaval
- ventral to the deep circumflex and external iliac arteries
- dorsal to ductus deferens
Describe the topography of the ureters ?
Topography of the ureters
Leave the renal pelvis medial aspect of the kidney - entering the trigone area of the bladder
- course ventral to the Psoas major and minor muscles
- the right ureter lies just lateral to the caudal vena cava
- passes ventral to the lateral ligament L shape
- the ureters then run obliquely within the wall of the bladder for a short distance toward the trigone before emptying into the lumen.
- “horse shoe shaped orifices” just cranial to the urethra
The intramural portion is variable attached to the outer longitudinal, middle circular and inner longitudinal muscles of the detrusor muscle (comprise the bladder wall).
Discuss the advantages and disadvantages of different imaging modalities for veiwing abnormalities of the ureters ?
Imaging modalities of the ureters
(normal ureter diameter 1.3-2.7mm dog but dilates 17x with diuresis.)
Ultrasound (the most sensitive modality)
- sensitivity 100% dogs, 77% cats
- can detect all stone types and soft tissue damage
- identify hydroureters
- hydronephrosis, may take days to develop
(>10mm likely complete obstruction).
Radiography
- only detects radio opaque stones (but covers most stones)
- lateral x2 and ventrodorsal
- stone size, number, and location
Fluroscope imaging
- good quality modality to detect urethral obstructions or uretal rupture
- antegrade pyelography (Invasive)
- retrograde pyelography
Imaging CT
- IV contrast
- associated risk of nephron damage
- can differentiate partial / or complete obstruction
Describe the medical options for treatment of an obstructed ureter, and demonstrate an understanding of when surgical intervention is required ?
Obstructed ureter
Medical treatment obstructed ureter
- Mannitol
- attempt diurese (increase urine volume) in an attempt to flush the ureters 1-4 days prior to commiting to surgery
- induce relaxation of uretal smooth muscle (dilation)
Indications for surgery to correct an obstructed ureter
(remember your goal is to maintain kidney function)
- unsuccessful medical treatment
- pain in patient + inability to urinate
- the benifits of avoiding surgery must be weighed against the risk of increasing renal damage secondary to obstruction.
Describe the clinical signs and biochemistry of a uretal obstruction ?
Uretal obstruction
Upon physical exam
- renal pain
- asymetric kidneys on palpation
Cat CBC
- anaemia
- azotaemia
- hyperphosphataemia
- hyperkalaemia
- hypocalcaemia / hypercalcaemia
Dog CBC
- neutrophilia
- thrombocytopenia
- azotaemia (increased nitrogenous waste)
Urinalysis
- haematuria
- crystalluria
- urine culture is positive
Confirm the pressence of a urethral obstruction through radiograph, ultrasound or retrograde pyelograph
Identify the treatment options for an obstructed ureter and its prognosis ?
Treatment options for an obstructed ureter
The length of the obstruction is usually unknown - therefore prognosis is difficult to predict
- most cats have a degree of nephritis post treatment.
- if azotaemic cat bilateral renal disease and MR 20%
Medical = mannitol
Surgery
Old techniques
Ureterotomy
- removal of obstruction (dilation occurs proximal to the site of the obstruction)
- nephrostomy
- renal transplantation
- uretal resection
New techniques
- Uretal stent
- Subs (subcutaneous urethral bypass) + easier sampling via the bypass
- extracorporeal shockwave lithrotripsy
Compare and contrast the “new techniques” to the older techniques and explain the advanatge of the newer techniques for treatment of irreversible uretal obstruction ?
Surgical correction uretal obstruction
Old techniques
- ureterostomy
- uretal transection + anastomosis
- nepthrostomy
- neoureterocystostomy
- ureteronephrectomy
New techniques
- uretal stent
- SUBS subcutaneous urethral stent
- shockwave lithrotripsy (nephroliths <10mm, ureteroliths <5mm)
The advantage of the newer surgical techniques is the overcome the complication of post operative urethral stricture.
Describe the aetiology and clinical signs of an ectopic ureter ?
Ectopic ureter
This is a congenital abnormality, caused by abnormal differentiation of the mesonephric duct
- often in conjunction with other congenital abnormalities
Intramural dogs
- within bladder but directed ventrally
Extramural cats
- completely bypasses the bladder to the urethra, vagina
- distal termination of the ureter is located distal to the end of the bladder
Ectopic ureters clinical signs
- Most common young female dogs
- - predisposed breeds lab, goldie
- uncommon in cats
- continuous or intermittent incontinence
- young fails to house train
- urine scalding
- normal voiding patterns
- partial response to USMI medication
- frequent licking of vulva
Describe how you could diagnose a suspected case of ectopic ureters ?
Diagnoses ectopic ureters
(Observation of a ureter that travels distal to the trigone region of the bladder is considered diagnostic of an ectopic ureter).
CBC, biochemistry
- should be normal (unless infection present).
Gold standard Cystoscopy + IVP
- not possible in cats
- ureters located in the same track as their biological origin
Intravenous pyelogram IVP
- series of X rays of kidney, ureter and bladder
- injection contrast
- can be difficult to detect intramural ureter - loss of J shape = straight ureter
- help determine concurrent renal abnormalities
- 76% accurate for ectopic ureters, and only 66% accurate for determining the location of the opening.
Ultrasound
- loss of jet flow from ureters at the trigone
- ultrasound and radiograpghs equally sensitive for ectopic ureters
Describe all the potential treatment options for ectopic ureters ? (6)
Ectopic ureters treatment options
- Medical only achieves a partial response
- diethylstilbestrol alph adrenergic agonist (phenylpropanolamine) - Uretal stent or subcutaneous urethral bypass
- Neoureterocystostomy
- Intravascular, ureter transected, small incision made in the dorsal bladder mucosa + ureter puuled into lumen trimmed and sutured.
- Extravascular spatulated ureter is sutured to the bladder mucosa with knots outside the lumen - Neoureterostomy
- Side to side
intramural ureter is located and incision made dorsal bladder - sutured to ureter mucosa
ligation, excision and laser - Minimally invasive cystoscopy
- use of a laser or scissors to cut the intramural part of the ectopic ureter
- around 70% continence when combined with medical management. - Nephrectomy and Ureteroectomy
Describe how you could classify ectopic ureters ?
Classification of ectopic ureters
(Based on their migration pathway)
Extramural
- ureter runs outside the bladder and opens directly into the vesicourethral junction, urethra, vagina or vestibule.
- bypass the trigone completely
Intramural ectopic ureter
- ureter runs into the erosal surface of the bladder at a normal position, but fails to terminate and opens into the bladder at the tip of the trigone
- disruption of the smooth muscle at the proximal urethral sphincter mechanism submucosal ureteral tunnel.
Describe the blood and nervous supply to the ureters ?
Anatomy ureters
Blood supply
- cranially renal artery
- caudally prostatic / vaginal artery
Nerve supply
- celiac and pelvic flexures
Normal ureter diameter
canine 1.3-2.7mm
feline 1mm
dilates upto 17x with diuresis
Discuss the pathogenesis of hip dysplasia ?
Pathogenesis of hip dysplasia
Multifactorial aetiology
- Genetic factors
- Dietary factors
- Conformational factors
- Hip laxity
Three mechanisms which lead to laxity, which then lead to remodelling of the joint and stretching of the ligament.
1. Lack of muscle to dynamically constrain passive constraints
2. Late ossification of bones means they are softer
3. Increased weight contributes to increased rim force
4. This is followed by micro-fracturing
5. Acetabular femoral remodelling
6. Stretching of the capsule and ligament
7. Increasing joint fluid
Know the techniques to diagnose hip dysplasia ?
Hip dysplasia
There are two clinical presentations
- 6-9 months associated with hip laxity / synovitis
- Mature dog associated with osteoarthritis
Presenting signs
- Gait abnormality / lameness
- Difficulty rising
- Reluctance to exercise
- Crying in pain
- Inability to jump
Diagnoses
Thorough history recording and general physical exam
- Lameness examination - with patient standing assess muscle atrophy, stance
- In lateral recumbency palpate for range of movement and pain
- Palpation for hip joint laxity
- Radiographic evaluation
Ortolani sign
- Assessment of hip laxity and angle of the acetabulum (open vrs closed)
- Can be performed in dorsal and lateral recumbency
- Requires deep sedation
- Angle of reduction
- Angle of subluxation
- Thumb greater trochanter, rotate the stifle upwards until a clunk is felt (Ortonloni +ve)
- Characteristics of “clunk” help assess damage to the acetabular rim (soft, hard, small vrs big clunk)
Hip lift / Bardens test
- positive result is trochanter can be elevated more than 6mm.
Radiograpghs
Standard extended VD view
Much critism
- Non-functional position
- May artificially reduce hip laxity (screw in effect)
- Lack of progress and early detection for breeding programs
PennHIP (extended, compression and distraction)
- Stress radiographic diagnostic method
- Database / registry
- International network of hip evaluation centres
- Assessment on three different vies, extended compression and distraction
- PennHIP at 4 months allows for early diagnosis and the ability to select within breeding programs
- Does not mandate surgical treatment in absence of clinical signs
Describe the options available for treatment of a immature and mature dog presenting with signs of hip dysplasia or laxity ?
Surgical intervention must be weighed against relatively favourable results of conservative management.
Conservative management / young dogs
- Triple pelvic osteotomy (TPO)
- Juvenile symphysiodesis (JPS)
- Femoral head excision (FHO)
Mature dogs
- Conservative management
- Total hip replacement (THR)
- Femoral head ostectomy (FHO)
- Capsular denervation
What is conservative management of hip dysplasia ?
Conservative management
The aim is to improve blood flow, relax muscles, improve mobility and relieve pain
- Strict confinement and controlled exercise
- Specific exercises / heat / massage / stretching
- Dietary management / weight loss
- Pain management /NSAIDS Metacam
- NSAID side effects gastro irritation, impairment of renal function and platelet dysfunction.
- Physical therapy
- Ultra glucosamine / nutraceuticals
Describe the process of a TPO, and its indications ?
Triple / double pelvic osteotomy (TPO)
Aim to rotate the acetabular segment of the pelvis to provide better femoral head coverage
- Young dogs
- Select animals with significant CS and no radiographic signs of hip OA
- Significant hip laxity on palpation
Describe a JPS and its indications ?
Juvenile pubic symphysiodesis (JPS)
- Requires early detection
- Young dogs (3-5) months before disease has present clinically
- Prophylactic surgery
Describe a FHO and THR and its indications ?
Femoral head Ostectomy
- Early surgery before severe atrophy
- Craniolateral approach
- Remove neck including the caudal shelf
- Palpate excision site thoroughly
Hip dysplasia / Total hip replacement
- Specialist area
- Definitive treatment for mature dog with sever pain due to OA
- Provides excellent functional results
- Surgical complications significant
- Cemented and uncemented techniques
- Unresponsive to medical treatment and unable to perform normal function in a mature dog
- No other orthopaedic / neurological disease
List the grade of petalla luxation ?
Grading of patellar luxation
Grades 1 to 4 – mild to most severe
( Grading one to four depending on the tendency of patella to luxate and ease of manual reduction).
- The higher the grade number, the more severe the bony changes
- Accurate assessment is critical to choosing the correct surgical treatment.
Grade one
- A knee-cap that can be luxated with manual pressure, but returns to the groove on its own.
- Dose not require specific treatment but should be monitored
Grade two
- The knne cap dislocates spontaneously when the joint is flexed or extended, but returns to the groove when the joint is extended and lateral pressure is applied.
- Often associated with a skipping lameness
Grade three
- The kneecap is permanently dislocated but can be manually returned to the groove.
- Often associated with consistent lameness and limb deformities
Grade four
- The kneecap is permanently dislocated and can not be manually returned to the groove
- Usually associated with severe lameness and limb deformities.
