1. Cystometry Characterization of Urinary Bladder Dysfunction in Chronically Paralyzed Dogs
Hilary Hu, Victoria Kichler, Chelsea Marko & Nick Jeffery
Iowa State University College of Veterinary Medicine
1. Increasing numbers of pet owners elect to keep dogs that have suffered
permanent thoracolumbar spinal cord injury as pets. In addition of loss of mobility
and sensation in the pelvic limbs, care of the urinary bladder can be problematic:
• Urinary incontinence
• Recurrent urinary tract infections & antibiotic resistance
• Detrusor hyper-reflexia
• Chronic bladder Pa elevation & secondary renal damage
Here we describe cytometric quantification of bladder dysfunction in chronic
(> 3 months) paraplegic pet dogs that are < 20 kg and had sustained severe T3-L3
spinal cord injury resulting in inability to walk or control urination.
2. A dual-lumen sterile urinary catheter was used for cystometry: one lumen was
used to infuse 0.9% sterile saline into the bladder while the other measured
intravesicular pressure. Infusion was terminated when:
(1) Leaking was apparent at the external urethral orifice; or,
(2) When physiologic maximum holding capacity of 20 ml/kg was reached; or,
(3) When the 50 cmH2O intra-vesicular pressure threshold was reached.
Several cystometric metrics were measured in this study:
(1) Intravesicular pressure at leak;
(2) Bladder holding capacity (% of physiologic max. holding capacity); and
(3) Bladder compliance (change in bladder volume divided by change in intra-
vesicular pressure).
3. Cystometric data was recorded in 42 dogs:
Mean Median Range
Intravesicular Pa (cmH2O) 18.6 17 1-50
Compliance (ml/cmH2O) 27.3 5.1 0.4-180
Holding Capacity (%) 68 68 9-100
In 2 (5%) patients, intravesicular pressure reached the 50mmHg threshold
4. We conclude that there is
evidence that detrusor hyper-
reflexia occurs in a small proportion
of dogs paralyzed because of
severe T3-L3 spinal cord injury. It is
characterized by elevation in
intravesicular pressure and
reduction in bladder compliance and
holding capacity. Potential therapies
for treating detrusor hyper-reflexia,
which can lead to secondary renal
damage, can now be evaluated
using these quantifiable bladder
functional parameters.
Acknowledgements
• Dr. Nicolas Granger
• Lloyd Veterinary Medical Center
• International Spinal Research Trust (sponsor)