Equine Urinary Tract Surgical Conditions PDF

Overview Surgical Conditions of the Equine Urinary Tract Sarah Gray, DVM, DACVS-LA VCM 653 Objectives • Understand how anatomic differences affects the relative risk and treatment of urinary tract obstruction • Recognize common presenting complaints for urinary tract disease and select appropriate...

Overview Surgical Conditions of the Equine Urinary Tract Sarah Gray, DVM, DACVS-LA VCM 653 Objectives • Understand how anatomic differences affects the relative risk and treatment of urinary tract obstruction • Recognize common presenting complaints for urinary tract disease and select appropriate diagnostic techniques • Identify common conditions in adult horses and foals • Understand the need for and how to perform medical stabilization of a uroabdomen • Anatomy & general considerations • Conditions affecting adults • Urolithiasis • Bladder eversion • Conditions affecting foals • Uroperitoneum • Patent urachus • Ectopic ureter Anatomy Mares Geldings/Stallions General Surgical Considerations • You may be working in a (deep) hole • Have long surgical instruments available • Consider laparoscopy • Choose suture material appropriate to tissue type • Never non-absorbable • The renal system is important in pharmacology • Can use this to your advantage ex) SMZ’s • Renal effects of antimicrobials and anti-inflammatories • Sensitive to hypoperfusion from hypotension Urolithiasis • Calcium carbonate primarily Conditions Affecting Adults • Equine urine is rich in calcium! • Anywhere in urinary tract • Bladder most common in horses • Males > females • Two types of calculi • Type 1 • Yellow-green, spiculated • 90% of all equine stones! • Type 2 • Smooth • Phosphate containing • More resistant to fragmentation Urolithiasis Removal • Clinical signs • Dietary management?? • Surgical removal • Hematuria • Stranguria • Diagnosis • Laparocystotomy • Transurethral removal • Palpation • Ultrasound • Cystoscopy Surgical Approaches for Bladder Stones Surgical Approaches for Bladder Stones • Fast for 24-36 hours • Approaches • Approaches, cont’d • Caudoventral midline • Only useful in mares • Paramedian with reflection of prepuce • Need to avoid superficial epigastric and external pudendal vessels • Parainguinal • Eliminates need to reflect prepuce • Laparotomy assisted parainguinal • Hand in ventral midline incision helps guide bladder toward inguinal incision • Advantage: can determine optimal size and location of parainguinal incision • Laparoscopy assisted parainguinal approach • Laparotomy assisted parainguinal • Hand in ventral midline incision helps guide bladder toward inguinal incision • Advantage: can determine optimal size and location of parainguinal incision • Laparoscopy Surgical Procedure Surgical Procedure • Get bladder to incision • https://www.youtube.com/watch?v=_S7a_KAOm-8 • • • • Gentle steady traction on bladder Buscopan Catheterize when placed on table and clamp allowing bladder to distend Distend with 100mL lidocaine; then via gravity flow with warm saline • https://www.youtube.com/watch?v=TcmplWxfVAo • Isolate bladder • Transverse incision • Have to peel mucosa from stone • Closure • 2-layer inverting with monofilament • Lavage abdomen and close Transurethral Removal Transurethral Removal • In some mares, can just dilate urethral and remove • Fragment stone as need • Small handed doctor! • Geldings need perineal urethrotomy • Pneumatic lithotripsy • Mallet and osteotome • Laser lithotripsy • Pulsed dye laser (acoustic waves) • Holmium:YAG (photothermal action) • https://www.youtube.com/watch?v=snt1NQUF-P4 Perineal Urethrotomy Perineal Urethrotomy • Performed for temporary diversion of urine, access to bladder stones, urethral rents • Typically heals in 3 weeks (unless made permanent) • Done under standing sedation + caudal epidural Perineal Urethrotomy Perineal Urethrotomy • Incision made 5cm distal to anus • Dissect soft tissue down through penis retractor muscle down to bulbospongius penis Perineal Urethrotomy Perineal Urethrotomy • Incise bulbospongiosus to exposure corpus spongiosum Perineal Urethrotomy Urolithiasis • Complications • Peritonitis, midline incisional complications • Stricture, hemorrhage, urine scald • Prognosis • Good, but recurrence in up to 41% • Changes post-operatively • Promote diuresis • Reduce calcium (reduce alfalfa and any supplementation) Urethral Obstruction Urethral Obstruction • Neoplasia (SCC, melanoma, sarcoid) – typically distal • Parasitic granuloma – typically distal • Urolithiasis – typically as junction of pelvic and extrapelvic urethra • Avoid alpha 2 agonists! • Diagnostics • Physical exam findings • Serum biochemistry • Clinical signs • Renal colic due to bladder distention • Frequent posturing to urinate Surgical Options Urethrorrhexis • Phallectomy • Secondary to kicks or other external trauma • Pronounced soft tissue inflammation secondary to urine in soft tissue • Can usually manage with indwelling urinary catheter unless completely transected • See “Conditions of the male reproductive tract” lecture • Distal urethrotomy • Essentially the same as a PU, but at different location • Incision directly over obstruction or slightly proximal • Can leave open to heal or close • Perineal urethrototomy Urethral Rent Corpus Spongiotomy • Typically at the dorsocaudal surface at ischial arch • Same steps as PU • Don’t cut into urethra • Clinical signs • Hematuria or hemospermia • Diagnosis: cystoscopy • Treatment: perineal urethrotomy or corpus spongiotomy Urethral/Bladder Surgery Aftercare Bladder Displacement • Monitor for normal urination • Antimicrobials and anti-inflammatories as appropriate • Rare • Only mares • Extrusion vs prolapse/eversion • Treatment • TMS/SMZ • NSAIDS (typically flunixin meglumine) • Phenazopyridine (4-6 mg/kg PO q8-12 hrs) • Chronic catheter placement is debated • May increase risk of urethral stricture • Protect skin from scald • • • • Cleanse Epidural Replace Foley catheter & purse string closed Foal Anatomy Conditions Affecting Foals Patent Urachus Patent Urachus • Urine from urethra and urachus • Treatment • Amount varies significantly • Medical management • Dipping umbilicus to prevent infection (0.5% chlorhexidine) • Antimicrobials as appropriate • Simple vs secondary • Clinical signs • Surgical management • Wet navel • Urine from urachus • Severe or non-resolving in 5-7 days • Cystoplasty Photo courtesy Dr. Sandra Yucupicio Cystoplasty Infected Umbilicus • Amputation of apex of bladder • Aka – omphalophlebitis or omphalitis • Foals < 8 weeks Risk factors: • Patent urachus or bladder tears at apex • Failure of passive transfer • Other infections Infected Umbilicus Infected Umbilicus • Diagnosis • Treatment • Visual appearance • Ultrasound! • Increased diameter • Hyperechoic material • CBC • Medical management • Broad spectrum until culture results obtained • Surgical resection  cystoplasty • • • • Large abscesses If little to no improvement Multiple problems (umbilicus is nidus for septic joints) Finances?? • Prognosis Uroperitoneum • Bladder tears or urachal rupture • Dorsal aspect of bladder • Up to 2% of neonates but higher in hospitalized foals • Care in how we assist to stand • Clinical signs • • • • • Lethargy Inappetence Tail flagging Repeated posturing to urinate Abdominal distention Uroperitoneum • Diagnosis • Serum biochemistry • Ultrasound • Peritoneal fluid analysis • Creatinine • 2:1 ratio – best diagnostic! • Methylene blue Uroperitoneum Surgical Repair • Medical emergencies! • Cystorraphy - direct suturing of the bladder tear • Abdominal compartment syndrome  poor ventilation and CO • Hyperkalemia  bradycardia • Stabilization • Decompress the abdomen • Increased lung function & decreased potassium • Slowly!! • Fluid therapy • Intranasal oxygen therapy Na ↓ K ↑ Cl ↓ BUN Variable, but usually ↑ CRE ↑ Surgical Repair Uroperitoneum • Prognosis • Overall good • Recurrence in 12-16% Photo courtesy Dr. Santi Gutierrez-Nibeyro Cystorrhapy vs. Cystoplasty Ectopic Ureter • Cysto = bladder • -rrhapy = surgical repair • -plasty = to modify • Ureter opens somewhere other than into the bladder • Cystorrhaphy is to simply repair the tear. Yes - we remove the umbilical structures, but we don’t change the bladder • Cystoplasty is removing the apex of the bladder with the umbilical structures • Urethra, uterus, vagina • Rare • Clinical signs: • Incontinence (either constant urinating or urine scald) • Diagnosis • Cystoscopy • Treatment • Ureterocystotomy (reimplantation of ectopic ureter into bladder) • Can do if ureter is close • Nephrectomy • If not close and unilateral Questions?