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.     

Preliminary results of intraoperative photodynamic therapy with 5-aminolevulinic acid in dogs with prostate carcinoma

Six client-owned dogs with prostate carcinoma were treated with a combination of (1) partial subcapsular prostatectomy using an Nd:YAG laser, (2) intraoperative photodynamic therapy using a halogen broad band lamp after local administration of a photosensitiser, and (3) systemic treatment with meloxicam. Median survival time was 41days (range 10-68days), which compared negatively with previous reports of subtotal laser prostatectomy combined with topical interleukin-2 administration, and photodynamic therapy alone. Despite treatment, the disease progressed locally, causing signs of stranguria to recur, and in the form of distant metastases. The recurrence of clinical signs due to the primary tumour despite photodynamic therapy is probably largely explained by insufficient penetration of light into the tissue. Better results may be obtained using other light sources (e.g. laser) and alternative techniques of light delivery, such as fibres or catheters allowing interstitial diffusion of light.     

Subtotal intracapsular prostatectomy as a useful treatment for advanced-stage prostatic malignancies

OBJECTIVES: Palliative surgery for advanced-stage prostatic cancers was tested with regard to survival rate and complications in a prospective randomised clinical study of dogs. Currently, therapeutic approaches have a grave long-term prognosis in clinically significant prostatic cancer. METHODS: Of 167 dogs with prostatic disorders, 24 were diagnosed with prostatic cancer. Eleven dogs underwent subtotal intracapsular prostatectomy, while in 10 dogs total prostatectomy was performed. The remaining three dogs were euthanased at their owner's request. Dogs treated by subtotal intracapsular prostatectomy and those treated by total prostatectomy were followed until their death. RESULTS: It was found that dogs treated by subtotal intracapsular prostatectomy survived 5.63 times longer (mean [sd] 112.0 [63.03] days) than those treated by total prostatectomy (19.9 [10.67] days) (P<0.01). Moreover, a significant decrease in postoperative complications after subtotal intracapsular prostatectomy was recorded, especially with regard to urinary incontinence. CLINICAL SIGNIFICANCE: It was concluded that, in the authors' facility, treatment of prostatic cancer by subtotal intracapsular prostatectomy was superior to that by total prostatectomy, with respect to both postoperative survival and serious complications.     

Intraoperative radiotherapy of carcinoma of the prostate gland in ten dogs

Ten dogs with carcinoma of the prostate gland were treated with intraoperative orthovoltage radiotherapy (radiation therapy to surgically exposed tumors). Seven dogs had tumor growth confined to the prostate gland and urethra, and 3 dogs had carcinoma of the prostate gland and regional lymph node involvement. Total radiation doses delivered to the prostate gland of 9 dogs and the affected regional lymph nodes of 3 dogs, using orthovoltage x-rays, ranged from 20 to 30 Gy. Carcinoma of the prostate gland of one dog was intraoperatively irradiated to 15 Gy and was then given a boost of 40 Gy, using cobalt-60 teletherapy. Survival time ranged from 41 to 750 days after intraoperative radiotherapy. Median and mean survival times for all dogs were 114 and 196 days, respectively. The median survival time for 7 dogs with localized prostatic carcinoma was 180 days, which was longer, but not significantly longer (P = 0.09), than the median survival time of 80 days in 3 dogs having prostatic carcinoma and metastatic disease. Intraoperative radiotherapy was tolerated well and caused complete response in 5 dogs. However, surgical complications in 2 dogs, which had subtotal lymphadenectomy or prostatic biopsy performed concurrently at the time of irradiation, resulted ultimately in their deaths. The 2 other dogs with metastatic disease and 1 dog without metastatic disease also had poor response to treatment. Our results indicated that intraoperative radiotherapy is an effective treatment for localized prostatic carcinoma in the dog.     

PREPUBIC AND TRANSRECTAL ULTRASONOGRAPHY OF THE CANINE PROSTATE: A COMPARATIVE STUDY

A comparative study was conducted in ten dogs with signs of prostatic disease in order to evaluate the usefulness of the prepubic and transrectal ultrasonography for the examination of the prostate gland and for prostate biopsy guidance. Both techniques were adequate to identify the prostate gland and prostatic urethra. Transrectal ultrasound found 5 occurrencies of parenchymal echogenicity changes whereas the prepubic technique found only 2. Lesions in the cranial prostatic margin (two dogs) were detected only by prepubic ultrasound. Lesions of the caudal prostatic margin (six dogs), prostatic urethra disruption (two dogs) and prostatic capsule abnormalities (five dogs) were only recognized by the transrectal approach. Prepubic ultrasonography was useful for biopsy guidance of cranial prostatic lesions and transrectal ultrasonography was a good means for biopsy guidance of caudal lesions.     

Subtotal Intracapsular Prostatectomy Results in Normal Dogs

Subtotal intracapsular prostatectomy was performed on five normal dogs. All dogs were maintained for 60 days postoperatively. No urinary abnormalities were noted following surgery with the exception of transient urinary incontinence in one dog that lasted for 7 days. Upon termination of the study, the prostatic urethra had reepithelized in all dogs where a dorsal strip of epithelium was left in place during surgery.     

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 dependant 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.     

Urinary Incontinence after Prostatectomy in Dogs

Eleven dogs with prostatic disease were treated by total prostatectomy. Urinary incontinence persisted in three of nine dogs, two of which were also incontinent before surgery. The incidence of postoperative incontinence may be reduced by undermining the prostatic capsule to preserve as much prostatic urethra as possible. The risk of postoperative incontinence appeared greater if there was prostatic neoplasia or preoperative urinary incontinence.     

Neodymium:yttrium aluminum garnet laser ventriculocordectomy in standing horses

OBJECTIVE: To develop a technique for neodymium:yttrium-aluminum-garnet (Nd:YAG) laser ventriculocordectomy in standing horses and document healing in horses undergoing laser ventriculocordectomy. ANIMALS: 6 horses between 2 and 32 years old. PROCEDURE: Under endoscopic guidance, the left laryngeal ventricle was everted with grasping forceps and excised with an Nd:YAG laser, using 60 watts of power in a noncontact fashion (6,403 to 9,197 Joules). Following removal of the ventricle, the vocal cord was photoablated. Horses were examined endoscopically 2, 7, 14, 21, 30, and 47 days after ventriculocordectomy, and 1 horse was euthanatized on each of these days. At necropsy, the larynx was removed intact and examined grossly. Samples were collected for histologic examination of the ventriculocordectomy site. RESULTS: Endoscopic examination revealed granulation tissue by day 7, the start of epithelialization by day 21, and healing by day 47. At necropsy, 4 horses were found to have a small amount of ventricular mucosa remaining dorsally and 1 additional horse was found to have a mucocele. Granulation tissue was identified grossly and histologically in the horses euthanatized between 7 and 30 days after surgery. Incipient reepithelialization was evident histologically on day 14, and complete reepithelialization of the surgery site was evident by day 47. CONCLUSION AND CLINICAL RELEVANCE: Results suggest that ventriculocordectomy can safely be performed with an Nd:YAG laser in standing horses.     

Neodymium:Yttrium-aluminum-Garnet (Nd:YAG) laser ablation of an obstructive urethral polyp in a dog

A miniature schnauzer presented for evaluation of a persistent lower urinary tract obstruction. Further examination revealed that the dog had developed an obstructive, inflammatory polyp secondary to a long-standing urinary tract infection. The polyp was located within the proximal urethra and interfered with normal voiding. The polyp was visualized using flexible endoscopy and then was successfully ablated using the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser. The Nd:YAG laser is a potentially useful tool for treating various lesions of the lower urinary tract.     

Ultrasound-guided percutaneous drainage as the primary treatment for prostatic abscesses and cysts in dogs

Thirteen dogs with prostatic abscesses and cysts were treated using percutaneous ultrasound-guided drainage. Eight dogs were diagnosed with prostatic abscesses and five with cysts on the basis of cytopathological examination and bacterial culture of the prostatic fluid. Antibiotic therapy, based on culture and sensitivity results, was administered for a minimum of 4 weeks. Intact dogs were castrated after initial drainage. Repeat ultrasonography of the prostate was performed every 1 to 6 weeks, and any residual cavitary lesions were drained and fluid analysis repeated. The median number of drainage procedures required to completely resolve the lesions was two (range, one to four). No complications were observed after drainage, and clinical signs resolved in all dogs. None of the dogs developed clinical signs of recurrent abscesses or cysts in the follow-up period (median, 36 months; range, 10 to 50 months). Ultrasound-guided, percutaneous drainage of prostatic abscesses and cysts appears to be a useful alternative to surgical treatment in select dogs.     

Proximal Urethral Reconstruction Using a Distally Based Ventral Bladder Tube Flap An Experimental Study

Reconstruction of the proximal urethra using a distally based tube flap mobilized from the ventral bladder wall was performed on 12 clinically normal dogs after total prostatectomy and resection of 2 cm of membranous urethra. One dog was euthanized at 6 hours and one at 36 hours after surgery because of surgical complications. Five dogs were euthanized at 10 days, two dogs at 6 weeks and three dogs at 12 weeks. Advancement of the tube flap allowed for tension-free anastomosis to the membranous urethra. Vascular integrity was maintained in all flaps. Intermittent to continuous postoperative urinary incontinence occurred in 7 of 10 dogs. The incontinence was transient in all 6 and 12 week dogs except one in which a persistent stress incontinence developed. Mild to severe dysuria was noted in 8 of 10 dogs, but was also transient in all of the 6 and 12 week dogs, with the exception of one dog. Postoperative urethral closure pressure profilometry revealed decreased tone in the membranous urethra in all 6 and 12 week dogs. It was concluded that proximal urethral reconstruction, using a ventral bladder tube flap, is a viable technique that may permit functional urodynamic recovery in dogs with significant proximal urethral loss.     

Prostatic Neoplasia: In Search of a Treatment

Introduction:  Complete prostatectomy with healing and normal urinary function is reported for some prostatic diseases. However incontinence rates of up to 100% for neoplasia‐affected dogs have dampened surgeons' enthusiasm for performing prostatectomies. Hypothesizing that incontinence following prostatectomy for prostatic cancer is related to extensive dissection associated with advanced invasion, it is proposed that there exists a subset of dogs with prostatic cancer that require minimal dissection and have the potential for quality survival for pet and owner.
Materials and Methods:  Dogs that received prostatectomy for neoplasia were qualitatively reviewed for commonalities associated with an outcome viewed as successful by owner and veterinarian.
Results:  Early diagnosis (prostatomegaly‐castrated population, high index of suspicion, ultrasound guided cytology) with referral center staging (ultrasound, contrast CT) enabled selection of appropriate surgery (urinary drainage, stent, prostatic enucleation, extrapelvic urethral anastomosis, cystoprostatourethrectomy with ureterocolonic anastomosis) for several dogs.
Conclusions:  A massive demographic shift toward castrated dogs and widespread availability of abdominal u/s can distinguish dogs that may benefit from advanced staging technology and treatment for locally confined prostatic neoplasia.
Application:  Step one is local control. Though based on a dribble of cases, it is clear that some dogs with prostatic cancer can be cured and live high quality lives. We wanted to leak these results so that oncologists will encourage early aggressive investigation and referral for prostatomegaly in castrated dogs.     

Intracapsular Subtotal Prostatectomy in Normal Dogs: Use of an Ultrasonic Surgical Aspirator

In an attempt to reduce postoperative incontinence associated with excisional prostatectomy and the recurrence of prostatic disease after less radical surgeries, a new technique for subtotal prostatectomy was developed using an ultrasonic surgical aspirator. During laparotomy, a longitudinal incision was made in the ventral surface of each lobe of the prostate gland. Biopsies for histology and culture were taken. Through the ventral incisions, the ultrasonic surgical aspirator     

Effects of cyclophotocoagulation with a neodymium:yttrium-aluminum-garnet laser on corneal sensitivity,intraocular pressure,aqueous tear production,and corneal nerve morphology in eyes of dogs

OBJECTIVE: To determine effects of cyclophotocoagulation via administration of 100 J with a neodymium:yttrium aluminum garnet (Nd:YAG) laser on corneal touch threshold (CTT), intraocular pressure (IOP), aqueous tear production, and corneal nerve morphology in eyes of dogs. ANIMALS: 15 dogs. PROCEDURE: Noncontact Nd:YAG laser was transsclerally applied (10 applications; 25 W for 0.1 seconds for each application to each of 4 quadrants) to the ciliary body of the left eye of 15 dogs; the right eye was the control eye. Corneal integrity, CTT, tear production as measured by the Schirmer tear test (STT), and IOP were evaluated for 14 days following laser treatment. On day 14, dogs were euthanatized, eyes harvested, and corneas stained with gold chloride. Major nerve bundles were analyzed by use of a drawing tube attached to a light microscope, and maximum diameters were measured by use of image analysis software. RESULTS: All laser-treated eyes had significantly higher CTT values, compared with control eyes. Six of 15 laser-treated eyes developed ulcerative keratitis. On most days, IOP was significantly lower in laser-treated eyes in both morning and evening. Laser-treated eyes had a significant decrease of approximately 1 nerve bundle/corneal quadrant. Values for STT or nerve bundle diameters did not differ significantly. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of 100 J with a Nd:YAG laser effectively reduced IOP while increasing CTT and caused a significant decrease in number, but not diameter, of major corneal nerve bundles. Nerve damage and corneal hypoesthesia are etiologic factors in ulcerative keratitis following Nd:YAG cyclophotocoagulation.     

Transitional cell carcinomas of the urinary tract in a colony of beagle dogs

Gross and light microscopic features of transitional cell carcinomas (TCC) of the urinary tract were examined in Beagle dogs used for the study of the long-term effects of low-dose, whole-body, 60Co gamma radiation. Thirty-eight cases of TCC occurred among 990 dogs that were from 0 to 14 years of age. There was no conclusive evidence of a radiation effect. The 38 TCC were equally divided between male and female dogs, but there was a significant difference in the sex distribution of urethra-origin TCC. Eleven males had a primary urethral TCC compared to only two females. There was no significant difference between the urethra-origin and bladder-origin TCCs in the number of tumors that caused clinical signs, metastasized, or that contributed to the death of the dog. All cases of urethral TCC in male dogs occurred in the prostatic urethra. The majority of these cases were not recognized to be neoplasms at gross necropsy, but microscopic examination revealed the TCC. Our findings differ from previous reports stating that TCC occurs more frequently in female than male dogs, and they especially differ from reports claiming that urethra-origin TCC is predominantly a disease of female dogs.     

Neodymium:yttrium aluminum garnet surgical laser versus bipolar electrocoagulation for laparoscopic ovariectomy in dogs

OBJECTIVE: To compare use of neodymium:yttrium aluminum garnet (Nd:YAG) surgical laser and bipolar electrocoagulation (BEC) for laparoscopic ovariectomy (OVE) in dogs. STUDY DESIGN: Prospective clinical trial. ANIMALS: Female dogs (n=72). METHODS: Laparoscopic OVE by Nd:YAG laser (600 microm optical fiber, contact mode) in 36 dogs was compared with laparoscopic OVE by bipolar electro-coagulating grasping forceps. Dogs were paired (laser, electrocoagulation) matched for breed, age, body weight, obesity, and number of heat cycles. Duration of predetermined surgery times and total surgical time were compared between groups. Occurrence of intra- and postoperative complications and their effect on surgical duration were evaluated. RESULTS: Laser surgery resulted in a higher incidence of intraoperative mesovarial bleeding (12 times; 9 dogs) compared with electrosurgery (4 times; 3 dogs). Use of laser caused a 2 minute delay for transection of the left ovary compared with electrosurgery. Postoperative complication rates and convalescence were similar for both groups. CONCLUSIONS: BEC reduced surgical time and intraoperative mesovarial bleeding compared with laser resection. CLINICAL RELEVANCE: Although the laser was effective for laparoscopic OVE, bipolar electrosurgical laparoscopic OVE remained the method of choice.     

Use of cystoscopic-guided laser ablation for treatment of intramural ureteral ectopia in male dogs: four cases (2006-2007)

OBJECTIVE: To describe and evaluate the outcome of cystoscopic-guided laser ablation of intramural ureteral ectopia in male dogs. DESIGN: Retrospective case series. ANIMALS: 4 incontinent male dogs with intramural ureteral ectopia. PROCEDURES: Intramural ectopic ureters were diagnosed via preoperative computed tomography-IV urography and subsequent cystoscopy. Transurethral cystoscopic-guided laser ablation (diode laser [n = 3 dogs] and holmium:yttrium aluminum garnet laser [1]) was performed to proximally relocate the ectopic ureteral orifice to the urinary bladder. Fluoroscopy was used during the procedures to confirm that the ureteral tract was intramural and the ureteral orifice was intravesicular after the procedure. In 1 dog with bilateral ureteral ectopia, staged laser ablation was performed at 6-week intervals because of difficulty viewing the second ureter on the first attempt. All ureteral orifices were initially located in the middle to proximal portion of the prostatic portion of the urethra. Six weeks after surgery, imaging was repeated in 3 of 4 dogs. RESULTS: Postoperative dysuria or hematuria did not develop. All dogs were immediately continent after laser treatment and remained so at a median follow-up period of 18 months (range, 15 to 20 months) without medical management. Conclusions and CLINICAL RELEVANCE: Ureteral ectopia can cause urinary incontinence in male dogs and is usually associated with other urinary tract abnormalities. Cystoscopic-guided laser ablation provided an effective and minimally invasive alternative to surgical management of intramural ureteral ectopia.     

Chronic effect of transrectal split-focus ultrasonic ablation on canine prostatic tissue

The treatment time needed for high-intensity focused ultrasound (HIFU) ablation might be decreased substantially by using the split-focus approach, so we made a prototype 4.2-MHz split-focus therapeutic transducer combined with a small 6.5-MHz imaging ultrasonic probe for transrectally treatment of canine prostatic cancer and used it to experimentally evaluate the feasibility of using split-focus transrectal HIFU to ablate canine prostatic tissue without injuring surrounding tissues. The prostates of 5 dogs were transrectally treated with split-focus ablation at a peak intensity in the water of 1.7 kW/cm(2) for 4 s (4 shots) under the guidance of ultrasonic B-mode imaging. After ultrasonic exposure, the prostates became stiff because of thermal effect of HIFU. For the first 3-5 days after treatment, dogs were catheterized daily for urinary management and treated with oral antibiotics to prevent urinary tract infection. The dogs were able to urinate normally by a week after. Within two weeks a large centrally located cystic cavity had formed in the prostate by replacing the necrotic parenchyma around the prostatic urethra. Necropsy three months after treatment found the rectum and prostate capsule to be normal grossly and histologically. The 4 shots of split-focus HIFU destroyed the prostatic parenchyma and created a prostatic cavity 0.34-0.45 cm(3) in volume without injuring surrounding tissues. These results suggest that split-focus HIFU ablation could be used for noninvasive treatment of prostatic cancer in dogs.     

Laser lithotripsy for treatment of canine uroliths

OBJECTIVE: To confirm in vivo optimal laser energy settings previously determined in vitro for lithotripsy, to develop a technique for Ho:YAG laser lithotripsy, and to evaluate acute and chronic tissue effects of laser lithotripsy. STUDY DESIGN: Prospective, randomized preclinical trial. ANIMALS OR SAMPLE POPULATION: Nineteen intact, adult male dogs. METHODS: Via cystotomy, a single urolith was inserted into the urethra to the level of the base of the os penis to simulate obstruction. Uroliths (calcium oxalate, urate, or magnesium ammonium phosphate) were fragmented by Ho:YAG laser, in contact mode through a 320 micro optic fiber, passed through the operating channel of a 2.8 mm flexible endoscope. The time and total energy to fragmentation were recorded. Dogs were euthanatized immediately after lithotripsy (3 dogs) or at 3 days (7 dogs), and urethral lesions and any stone remnants were evaluated. Urethral integrity was also evaluated in 9 other dogs by endoscopy on day 10; these were also monitored clinically for 30 days. RESULTS: The mean time for adequate fragmentation was 166.7 seconds (range, 47-494.5 seconds). The mean+/-SD energy used was 1418+/-851.2 J. In part 1, 2 dogs were obstructed with urolith fragments at necropsy. Eight dogs had minimal (<30 mg) or no urolith material evident within the urethra. Four dogs had gross focal or circumferential erosion, ulceration, or hemorrhage of the urethral mucosa. Lesions were not associated with the site of laser irradiation in 2 dogs. In dogs observed for 30 days, hematuria, pollakiuria, and stranguria that were observed after lithotripsy, resolved in all affected dogs by day 5. No mucosal lesions were observed by endoscopy and none of the dogs became obstructed. CONCLUSION: Laser lithotripsy with the Ho:YAG laser in contact mode successfully fragmented obstructive uroliths in male dogs. CLINICAL RELEVANCE: Laser lithotripsy may be a clinically relevant technique for treatment of urolithiasis in male dogs; clinical studies to evaluate long-term effects on urethral mucosa and the role of repeat treatment for recurrence are indicated.