Electrohydraulic and extracorporeal shock-wave lithotripsy

Development of a burst wave lithotripsy system for noninvasive fragmentation of ureteroliths in pet cats

BACKGROUND

Upper urinary tract stones are increasingly prevalent in pet cats and are difficult to manage. Surgical procedures to address obstructing ureteroliths have short- and long-term complications, and medical therapies (e.g., fluid diuresis and smooth muscle relaxants) are infrequently effective. Burst wave lithotripsy is a non-invasive, ultrasound-guided, handheld focused ultrasound technology to disintegrate urinary stones, which is now undergoing human clinical trials in awake unanesthetized subjects.

RESULTS

In this study, we designed and performed in vitro testing of a modified burst wave lithotripsy system to noninvasively fragment stones in cats. The design accounted for differences in anatomic scale, acoustic window, skin-to-stone depth, and stone size. Prototypes were fabricated and tested in a benchtop model using 35 natural calcium oxalate monohydrate stones from cats. In an initial experiment, burst wave lithotripsy was performed using peak ultrasound pressures of 7.3 (n = 10), 8.0 (n = 5), or 8.9 MPa (n = 10) for up to 30 min. Fourteen of 25 stones fragmented to < 1 mm within the 30 min. In a second experiment, burst wave lithotripsy was performed using a second transducer and peak ultrasound pressure of 8.0 MPa (n = 10) for up to 50 min. In the second experiment, 9 of 10 stones fragmented to < 1 mm within the 50 min. Across both experiments, an average of 73-97% of stone mass could be reduced to fragments < 1 mm. A third experiment found negligible injury with in vivo exposure of kidneys and ureters in a porcine animal model.

CONCLUSIONS

These data support further evaluation of burst wave lithotripsy as a noninvasive intervention for obstructing ureteroliths in cats.

A Comprehensive Review of the Effects of Extracorporeal Shock Wave Therapy on Stroke Patients: Balance, Pain, Spasticity

Stroke remains a leading cause of disability worldwide, with survivors often experiencing impairments in balance, pain, spasticity, and control that limit their ability to perform daily living activities. Extracorporeal shock wave therapy (ESWT) has emerged as a potential treatment modality to improve these outcomes in stroke patients. This review aims to provide a comprehensive examination of the effects of ESWT on stroke patients, focusing on the theoretical background, balance, pain reduction, muscle spasticity and control, and upper and lower extremities. This study reviewed the use of ESWT in treating balance, pain, and spasticity in stroke patients, focusing on articles published in PubMed between January 2003 and January 2023. Systematic reviews related to stroke were used to provide an overview of stroke, and a total of 33 articles related to balance, pain, and spasticity were selected. ESWT has several shock wave generation methods and application methods, and it has been shown to have positive therapeutic effects on various aspects of rehabilitation for stroke patients, such as improving balance, reducing pain, decreasing muscle spasticity and increasing control, and enhancing functional activities of the upper and lower extremities. The efficacy of ESWT may vary depending on the patient's condition, application method, and treatment area. Therefore, it is important to apply ESWT according to the individual characteristics of each patient in clinical practice to maximize its potential benefits.

Urethral Urolithiasis in Male Cattle Treated Using Pneumatic Lithotripsy

One of the most important problems encountered in cattle breeding is urethral urolithiasis. Urolithiasis can be treated using various methods, but they all carry risks. Thus, a continuous search is being carried out for alternatives in this field. This study aimed to treat urethral urolithiasis in male cattle using pneumatic lithotripsy, a minimally invasive method. The urethra and penile tissues of 20 male cattle of different ages and breeds were obtained from slaughterhouse materials and measured before determining the probe diameters and lengths. The study included 9 male cattle (2 Simmental hybrids, 1 Zavot hybrid, 1 Brown, and 5 Simmental), between 4 months and 2 years of age, diagnosed with urethral urolithiasis. A modified lithotripsy apparatus was used for the pneumatic disintegration of urinary stones. The localization of urinary stones in the urethra was determined by palpation and catheterization. After laying the animal in a lateral position, a lithotripsy probe of appropriate length and diameter was advanced from the external urethral orifice to the site of localization. Once the probe came into contact with the stone, a vibration of 125 bar was applied until the stone was broken. The probe was removed, and the urethral channel was washed with 0.1% iodine solution to remove the shredded urethral stones. Uncomplicated recovery was achieved in all treated cases. In conclusion, pneumatic lithotripsy provided successful results in treating urolithiasis and can be used as an alternative surgical method in cattle. Moreover, the low cost is an additional advantage to breeders.

Treatment of chronic or recurrent proximal suspensory desmitis using radial pressure wave therapy in the horse

REASONS FOR PERFORMING STUDY

Proximal suspensory desmitis (PSD) is diagnosed with increasing frequency in horses and radial pressure wave therapy (RPWT) is a widely used therapy for painful orthopaedic conditions in man and dogs. There are, however, few published data as to the outcome of its use in PSD.

OBJECTIVE

To evaluate the use of RPWT in the treatment of chronic or recurrent PSD in the horse, an injury which carries a poor prognosis for return to athletic function with conservative management alone.

HYPOTHESIS

RPWT and controlled exercise improves the prognosis of chronic or recurrent PSD in the horse when compared to previously published results of controlled exercise alone.

METHODS

The use of RPWT in the management of chronic or recurrent proximal suspensory desmitis (PSD) was evaluated in 65 horses. Diagnosis was based on response to local analgesia, ultrasonography and radiography. Horses were classified according to severity of ultrasonographic lesions, whether fore- or hindlimbs were affected, and duration of lameness prior to diagnosis. Horses were treated 3 times at 2-week intervals and followed a controlled exercise programme; they were reassessed clinically and ultrasonographically 10-12 weeks after diagnosis, when further exercise recommendations were made dependent upon the animal's progress.

RESULTS

Forty-one percent of horses with hindlimb lameness and 53% with forelimb lameness were nonlame and returned to full work 6 months after diagnosis. The prognosis was significantly affected by the ultrasonographic grade at the time of diagnosis and by ultrasonographic evidence of resolution of the lesion in hindlimb cases.

CONCLUSIONS

These findings, when compared to previously published results of treatment using controlled exercise alone, suggest that RPWT improves the prognosis for PSD in the hindlimb.

POTENTIAL RELEVANCE

RPWT is a useful treatment modality for chronic or recurrent PSD when combined with controlled exercise. Further studies are required on the effect of RPWT employing histology and biomechanics in order to fully evaluate its use on equine tissues.

The use of radial extracorporeal shockwave therapy in the treatment of urethral urolithiasis in the horse: a preliminary study

BACKGROUND

Radial extracorporeal shockwave therapy (ESWT) is widely used in equine practice for the treatment of orthopedic problems. However, its original use as a lithotripsy device in human and canine urology led us to postulate that it could be used as an alternative to the surgical treatment of urethral calculi in horses.

HYPOTHESIS

Radial ESWT can easily and safely fragment calculi in the distal urethra of the horse.

ANIMALS

Two postmortem cases and 1 live case of obstructive urinary disease admitted at the Veterinary Teaching Hospital of Liege.

METHODS

A radial shockwave device was directly applied to the urethra in an attempt to fragment calculi. An ex vivo trial was performed on the same retrieved calculi to investigate pressure settings in order to obtain complete fragmentation of the calculus.

RESULTS

In all cases, radial ESWT was able to fragment the calculus partially, enabling retrieval of the remaining fragments via the urethra. Much higher pressure settings than those used for in vivo partial fragmentation were necessary to obtain complete destruction of the calculi ex vivo.

CONCLUSIONS AND CLINICAL IMPORTANCE

This brief report suggests the use of radial ESWT as a safe and useful alternative to more invasive surgical management of urethral calculi in horses.

Use of laser lithotripsy for fragmentation of uroliths in dogs: 73 cases (2005-2006)

OBJECTIVE

To describe use of transurethral cystoscope-guided laser lithotripsy for fragmentation of cystic and urethral uroliths and determine procedure duration and short-term and long-term outcome in dogs.

DESIGN

Retrospective case series.

ANIMALS

73 dogs with naturally occurring uroliths in the urinary bladder, urethra, or both.

PROCEDURES

Transurethral cystoscope-guided laser lithotripsy was performed in all dogs, and medical records were reviewed for short-term and long-term outcome and complications.

RESULTS

Laser lithotripsy resulted in complete fragmentation of all uroliths in all 28 female dogs and a majority of male dogs (39/45 [86.7%]). Dogs with urethroliths had shorter median laser time than dogs with cystic uroliths. Basket extraction and voiding urohydro-propulsion were successful for removal of the urolith fragments following laser lithotripsy. Complications related to cystoscope-guided laser lithotripsy occurred in 5 of 28 (17.9%) female dogs and 6 of 45 (13.3%) male dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

Transurethral cystoscope-guided laser lithotripsy was successful in female dogs and most male dogs for fragmentation of cystic and urethral uroliths. Short-term complications were most commonly related to urethral swelling and resolved with placement of an indwelling urinary catheter. There were no long-term complications.

Effect of nephrotomy on renal function and morphology in normal cats

OBJECTIVE

To assess effects over 12 weeks of bisection nephrotomy on renal function, size, and morphology in cats.

STUDY DESIGN

Controlled, randomized, blinded experiment.

SAMPLE POPULATION

Ten adult female cats.

METHODS

Glomerular filtration rate (GFR), determined by quantitative renal scintigraphy using (99m)Technetium-diethylenetriamine-pentaacetic acid, urinalysis, urine culture, and ultrasonographic measurement of renal size were performed preoperatively. Left or right nephrotomy (5 cats/group) was performed. Total and individual kidney GFRs were determined at 2, 28, and 84 days, ultrasonographic measurements at 28 and 86 days, and ultrasound-guided biopsy at 86 days.

RESULTS

No significant differences in mean GFR and kidney size of operated versus unoperated kidneys were observed. Individual GFR and renal size of all except 1 cat remained within normal limits. Two cats had evidence of transient ureteral obstruction in the immediate postoperative period. No significant, generalized histologic abnormalities were observed.

CONCLUSIONS

Bisection nephrotomy in normal cats does not adversely affect renal function or morphology during the initial 12 weeks.

CLINICAL RELEVANCE

Bisection nephrotomy can be safely performed in normal feline kidneys without causing a significant deleterious effect on renal function. Studies in cats with pre-existing renal insufficiency are needed to ensure adverse effects would not occur in clinical cases where this surgical procedure is warranted.

Spontaneous retrograde movement of ureteroliths in two dogs and five cats

CASE DESCRIPTION

2 dogs and 5 cats were evaluated for treatment of ureteroliths.

CLINICAL FINDINGS

Spontaneous retrograde movement of 1 or more ureteroliths was detected by radiography, ultrasonography, fluoroscopy, and a combination of fluoroscopy and ultrasonography. The ureteroliths moved retrograde up to 4 centimeters. Retrograde movement of ureteroliths into the renal pelvis resulted in improved renal function in some patients but made complete surgical removal of all uroliths more difficult.

TREATMENT AND OUTCOME

Medical management was not successful, and ureteroliths were surgically removed. Surgical management of ureteroliths was complicated by retrograde movement of ureteroliths in the perioperative period.

CLINICAL RELEVANCE

Ureteroliths can move retrograde within the ureter and even back into the renal pelvis. Retrograde movement of ureteroliths may make surgical planning more difficult.

In vitro evaluation of canine and feline calcium oxalate urolith fragility via shock wave lithotripsy

OBJECTIVE

To test the hypothesis that feline calcium oxalate uroliths are intrinsically more resistant to comminution via shock wave lithotripsy (SWL) than canine calcium oxalate uroliths through comparison of the fragility of canine and feline uroliths in a quantitative in vitro test system.

SAMPLE POPULATION

Calcium oxalate uroliths (previously obtained from dogs and cats) were matched by size and mineral composition to create 7 pairs of uroliths (1 canine and 1 feline urolith/pair).

PROCEDURE

Uroliths were treated in vitro with 100 shock waves (20 kV; 1 Hz) by use of an electrohydraulic lithotripter. Urolith fragmentation was quantitatively assessed via determination of the percentage increase in projected area (calculated from the digital image area of each urolith before and after SWL).

RESULTS

After SWL, canine uroliths (n = 7) fragmented to produce a mean +/- SD increase in image area of 238 +/- 104%, whereas feline uroliths (7) underwent significantly less fragmentation (mean image area increase of 78 +/- 97%). The post-SWL increase in fragment image area in 4 of 7 feline uroliths was < 50%, whereas it was > 150% in 6 of 7 canine uroliths.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicate that feline calcium oxalate uroliths are less susceptible to fragmentation via SWL than canine calcium oxalate uroliths. In some cats, SWL may not be efficacious for fragmentation of calcium oxalate nephroliths or ureteroliths because the high numbers of shock waves required to adequately fragment the uroliths may cause renal injury.

Evaluation of the effects of nephrotomy on renal function in clinically normal cats

OBJECTIVE

To evaluate the effects of nephrotomy on renal function in clinically normal cats.

ANIMALS

20 specific-pathogen-free, 9- to 11-month-old female mixed-breed cats.

PROCEDURE

Serum chemistry analyses, CBC determinations, urinalyses, microbiologic urine cultures, renal ultrasonography, abdominal radiography, and single-kidney and total glomerular filtration rate (GFR) determinations by use of renal scintigraphy and measurements of plasma disappearance of technetium 99m-diethylenetriaminepentaacetic acid were performed before surgery and at 3, 12, 26, 52, and 78 weeks after surgery in 10 cats that underwent unilateral nephrotomy and in 10 control cats that underwent a sham surgical procedure.

RESULTS

Two cats (1 from each group) did not complete the study, and their data were eliminated from analyses. Unilateral nephrotomy resulted in a 10% to 20% reduction in mean single-kidney GFR, compared with that of nephrotomy contralateral control kidneys. However, mean total GFR in nephrotomy-group cats was not significantly different from that of sham-group cats. Over the 78 weeks of study, mean total GFR declined 34% and 40% in nephrotomy- and sham-group cats, respectively. Adverse events associated with nephrotomy included persistent microscopic hematuria, renal pelvis hyperechogenicity with distant shadowing on ultrasonographic evaluation, dilatation of renal pelves, and hydronephrosis.

CONCLUSIONS AND CLINICAL RELEVANCE

Nephrotomy in normal functioning feline kidneys results in a modest relative reduction in renal function, compared with contralateral kidney controls, but has minimal effect on total GFR when compared with sham-operated control cats. However, any detrimental effects of nephrotomy may be magnified in cats with diseased kidneys, which may have little or no capacity for repair or compensation.

Management of ureteral obstruction

The most common cause of ureteral obstruction in dogs and cats is ureteral calculi. Common clinical signs associated with ureteral obstruction include abnormalities in urination, persistent urinary tract infection, abdominal pain, vomiting, anorexia, weight loss,and depression or lethargy. Medical management of ureteral obstruction includes fluid diuresis, muscle relaxants, and treatment of azotemia using nephrostomy tubes or hemodialysis. Surgical techniques used to restore patency to the ureter include ureterotomy,partial ureterectomy and ureteroneocystostomy, and ureteral resection and anastomosis. Lithotripsy has been used in dogs to remove ureteral calculi. Renal function can be preserved if complete ureteral obstruction is relieved within several days of onset.

Update: management of calcium oxalate uroliths in dogs and cats

Calcium oxalate has become the most common mineral occurring in canine and feline uroliths. Although calcium oxalate urolith formation may be a consequence of metabolic disease, the underlying cause is not identified in many dogs and cats. Currently, there is no successful medical dissolution protocol, and calcium oxalate uroliths must be removed physically if causing problems. Effective preventative protocols are available for dogs and cats, although they are not uniformly successful.

Lithotripsy: an update on urologic applications in small animals

Lithotripsy methods for fragmenting uroliths continue to evolve.Increasing access to and experience with newer generation lithotriptors and continued study of laser methodology are likely to increase the application of lithotripsy methods in small animal urology. For small animals in which intervention is recommended for progressive, symptomatic, infected, or obstructive uroliths, nonsurgical extracorporeal or intracorporeal lithotripsy methods maybe considered.

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.

In vitro effects of pulsed holmium laser energy on canine uroliths and porcine cadaveric urethra

BACKGROUND AND OBJECTIVES

To assess the effect of holmium laser energy on canine uroliths and porcine urethra.

STUDY DESIGN/MATERIALS AND METHODS

Uroliths of known composition and fresh cadaveric urethra were exposed to holmium laser energy. Urolith fragmentation times and depth of urethral lesions were determined.

RESULTS

Overall mean fragmentation time was 11.8 +/- 8.01 seconds. Magnesium ammonium phosphate (MAP) and urate uroliths had significantly shorter fragmentation times compared to other uroliths. Fragmentation time of MAP uroliths irradiated with 1.2 J/pulse was significantly longer than the fragmentation time of MAP uroliths irradiated with 0.3 J/pulse. Overall mean lesion depth for urethral specimens treated with 90 degrees contact mode irradiation was significantly greater than overall mean lesion depth for specimens treated with 30 degrees non-contact mode.

CONCLUSIONS

Holmium laser energy effectively fragmented canine uroliths and caused minimal urethral damage in vitro. Dogs with urolithiasis may represent a useful animal model for developing human lithotripsy procedures.