Intracapsular subtotal prostatectomy in normal dogs: use of an ultrasonic surgical aspirator

Investigation of the use of microwave ablation with and without cooling urethral perfusion for thermal ablation of the prostate gland in canine cadavers

OBJECTIVE

To investigate the use of microwave ablation (MWA) with cooling urethral perfusion and with no perfusion (MWA-UP and MWA-NP, respectively) for prostate gland ablation in canine cadavers.

ANIMALS

Cadavers of 18 sexually intact male dogs.

PROCEDURES

After technique refinement in 2 cadavers, laparotomy with ultrasound-guided MWA-UP (n = 8) or MWA-NP (8) of the prostate gland was performed in 16 cadavers. Normograde cystourethroscopy was performed before and after treatment; recorded images were reviewed in a blinded manner for scoring of urethral mucosal discoloration and loss of integrity. Difficulty with cystoscope insertion was recorded if present. Excised prostate glands were fixed for serial sectioning, gross measurements, and calculation of percentage ablation. Percentages of prostate tissue necrosis from MWA, denuded urethral mucosa, and depth of epithelial surface loss in an adjacent section of the colon were estimated histologically. Variables of interest were statistically analyzed.

RESULTS

Difficulty with cystoscope insertion after treatment was significantly more common and scores for urethral mucosal discoloration and loss of integrity were significantly higher (indicating more severe lesions) for the MWA-NP group than for the MWA-UP group. The histologically assessed percentage of denuded urethral mucosa was also greater for the MWA-NP group. Overall median percentage prostate gland ablation was 73%; this result was not associated with prostate gland volume or chronological order of treatment.

CONCLUSIONS AND CLINICAL RELEVANCE

MWA-UP induced subtotal thermal necrosis of prostate glands in canine cadavers while limiting urethral mucosal injury. Further study is required to optimize the technique and evaluate its safety and efficacy in vivo as a future curative-intent treatment for prostatic tumors in dogs.

Urodynamic and morphometric characteristics of the lower urogenital tract of male Beagle littermates from four months to two years of age

OBJECTIVE

To describe functional and anatomic changes of the lower urogenital tract of healthy male dogs during the sexually immature period and up to 2 years of age by urodynamic and morphometric assessment.

ANIMALS

6 sexually intact male Beagle littermates.

PROCEDURES

Dogs underwent electromyography-coupled urodynamic tests, CT-assisted retrograde urethrography, prostatic washes, and blood sampling monthly from 4 through 12 months of age and then at 3-month intervals. Urodynamic and morphometric variables and serum canine prostate-specific esterase concentrations were analyzed by statistical methods.

RESULTS

Integrated pressure of the urethra was significantly increased beginning at 8 months of age, compared with earlier time points. Urethral pressure peak amplitudes varied among anatomic regions. During bladder filling, few electromyographic signals were concurrent with urethral pressure peaks; these were most commonly detected in the penile portion of the urethra. Urethral length and prostate gland volume were significantly greater from 7 to 24 months of age than at younger ages. Urethral length was approximately 26 to 27 cm after 9 months, and prostate gland volume was approximately 11 to 12 cm³ after 11 months of age. Serum canine prostate-specific esterase concentrations correlated with prostate gland volume. Urinary bladder threshold volume was significantly increased at 6 months of age, compared with that at 4 months, with a maximum of 197.7 mL at 24 months.

CONCLUSIONS AND CLINICAL RELEVANCE

Urethral resistance was acquired at approximately 8 months of age, when growth of the lower urinary tract was incomplete. Electromyographic and integrated pressure measurement results and the distribution and amplitude of urethral pressure peaks highlighted the potential role of the prostate gland and possibly the bulbocavernosus muscles in control of continence.

Evaluation of intracranial meningioma resection with a surgical aspirator in dogs: 17 cases (1996-2004)

OBJECTIVE

To determine results of intracranial meningioma resection by use of a surgical aspirator and assess prognostic factors associated with intracranial meningiomas in dogs.

DESIGN

Retrospective case series.

ANIMALS

17 dogs.

PROCEDURES

Medical records of dogs that underwent resection of an intracranial meningioma by use of a surgical aspirator were reviewed. Information pertaining to signalment, imaging findings, clinical signs, duration of clinical signs, preoperative treatment, location of the tumor, results of histologic assessment, outcome, and necropsy results was obtained from the medical record. Clients and referring veterinarians were contacted via telephone for information on recurrence of clinical signs and postoperative survival time.

RESULTS

16 dogs were > 7 years of age, and all 17 dogs had seizures before surgery. The most commonly affected breed was the Golden Retriever, represented by 6 of the 17 dogs. Median survival time was 1,254 days. Of the data collected, only histologic subtype of the tumor was prognostic. Analysis of survival times according to histologic tumor subtypes indicated that the order from most brief to longest was as follows: anaplastic, 0 days; fibroblastic, 10 days; psammomatous, > 313 days; meningothelial, > 523 days; and transitional, 1,254 days.

CONCLUSIONS AND CLINICAL RELEVANCE

Use of a surgical aspirator to resect intracranial meningiomas in dogs was associated with longer survival times than those achieved with traditional surgery alone or traditional surgery combined with radiation therapy. Dogs with meningothelial, psammomatous, or transitional intracranial meningioma subtypes appeared to have a better prognosis than dogs with other subtypes of meningioma.

Partial Prostatectomy Using Nd:YAG Laser for Management of Canine Prostate Carcinoma

OBJECTIVE

To report a technique for partial prostatectomy by laser dissection and to evaluate outcome and complications in dogs with prostate carcinoma (PCA).

STUDY DESIGN

Experimental and clinical case series.

ANIMALS

Four normal dogs and 8 dogs with PCA.

METHODS

Subcapsular partial prostatectomy, sparing the urethra and the dorsal aspect of the prostatic capsule, using Nd:YAG laser dissection to remove the prostatic parenchyma and control hemorrhage was performed in 4 normal dogs and subsequently in 8 dogs with histologically confirmed PCA. Additional treatment of PCA dogs included local application of interleukin-2 and systemic administration of meloxicam. Prostate size, complications, and survival time were recorded. Laser-associated thermal damage to surrounding tissue was evaluated by histology.

RESULTS

In normal dogs, no damage to the dorsal prostatic capsule or urethra was detected. In PCA dogs, median survival was 103 days (range, 5-239 days). Three dogs died from complications within 16 days, whereas 5 (median survival, 183 days; range, 91-239 days) had improvement or resolution of clinical signs. Urinary incontinence did not occur.

CONCLUSION

Laser assisted subcapsular partial prostatectomy can be performed in dogs with PCA without development of postoperative incontinence.

CLINICAL RELEVANCE

Subcapsular partial prostatectomy is a potential palliative treatment for PCA in dogs and may lead to the resolution of clinical signs for several months.

Reproductive oncology

The actual incidence of reproductive tract tumors is difficult to ascertain, presumably because a significant percentage of dogs and cats are neutered, particularly in the United States. Data from European countries, where elective neutering is less common, provides insights. Several studies document the relative frequency of reproductive tumors. Larger studies of the more common tumors, e.g., testicular tumors, provide a substantial amount of information on the clinical presentation and response to treatment of dogs, but overall there is less information available on cats. Numerous case reports document the less commonly reported tumors and will be included in the following discussion.

Distinct vascular zones in the canine prostate

The vascular bed of canine prostate was studied and detailed distinct vascular zones were visualized on corrosion casts by scanning electron microscopy. This study was performed because of scarce information about the zonal vascularization of the prostate gland in dogs. There are no studies for three-dimensional microvascular distribution of the capsular vessels and the capsular microvascular trabeculae. SEM (vascular corrosion casting method) was used to show 3D angioarchitecture of the prostate gland. The lobules on the dorsal and lateral surface of the gland were numerous but small. Their small size is probably due to the abundant blood supply in the region. Few but large ventral lobules were observed. Three prostatic zones were clearly defined: capsular, parenchyma, and urethral. The diameter of the venous blood vessel compared to arterial vessels of the capsule was smaller. Two types of arteries were observed in trabeculae: direct and branched. The direct arteries were straight, with only a few branches. The branched arteries contained many bifurcations, with the vessel's diameter decreasing gradually. The trabeculae capillary network formed loops, with frequent sphincter-like constrictions and pouch-like protuberances.

Prostatic surgery in the dog

Prostatic diseases are commonly encountered in the dog and a significant proportion of these will require some form of surgical intervention for their successful resolution. The previous perception of the prostate as an obscure pelvic organ coupled with a range of heretofore complex and unsatisfactory surgical techniques have deterred many surgeons from attempting surgical intervention. The recent introduction of omentalization techniques for the management of prostatic infections and secretory abnormalities, which require only modest surgical expertise, has now provided simple solutions for all benign parenchymal diseases. However, neoplastic disease remains a difficult disease both to diagnose and manage.

Partial resection and omentalization: a new technique for management of prostatic retention cysts in dogs

OBJECTIVE

The purpose of this study was to determine the results of a new technique for management of prostatic retention cysts in dogs.

STUDY DESIGN

A retrospective clinical study.

ANIMALS

Eighteen client-owned dogs.

METHODS

Dogs with prostatic retention cysts were treated by celiotomy and drainage of the cysts. The majority of the cyst wall was resected and residual cyst cavities were packed with omentum. All dogs were castrated.

RESULTS

Long-term resolution of clinical signs was achieved in all dogs, with follow-up periods ranging from 6 to 42 months. Five dogs developed urinary incontinence postoperatively. This persisted in two dogs, but was well controlled with phenylpropanolamine. In the remaining dogs, the incontinence was transient and resolved within 2 months of surgery.

CONCLUSIONS

Partial cyst resection combined with omentalization and castration was a simple and effective means of managing prostatic retention cysts. The incidence of serious complications, including postoperative urinary incontinence, was low.

Intracapsular prostatic omentalization: a new technique for management of prostatic abscesses in dogs

Twenty dogs with abscessation of the prostate gland were treated by celiotomy, drainage, and digital exploration of the gland through bilateral capsulectomy wounds. Omentum was introduced through the capsulectomy wounds and packed into the abscess cavities around the prostatic urethra. Most dogs were discharged from the hospital within 48 hours of the surgery. Long-term resolution of the problem (no recurrence within 12 months) was achieved in 19 dogs. One dog had recurrent abscessation that was managed by the placement of dependent Penrose drains. Temporary tube cystostomy was performed postoperatively in one dog for the management of transient dysuria. One dog with septic peritonitis resulting from preoperative abscess rupture was managed by concurrent open peritoneal drainage. Intracapsular prostatic omentalization was a simple and effective means of managing prostatic abscessation with minimal requirement for postoperative hospitalization of the patient. The frequency of serious complications, including postoperative urinary incontinence, was low.