Biomedical subjects

James D Watterson

Publications and source records attributed to James D Watterson.

18 recordsLinked to original sources

PubMed2006

Access related complications during percutaneous nephrolithotomy: urology versus radiology at a single academic institution.

PURPOSE: A recent survey revealed that only 11% of urologists performing percutaneous nephrolithotomy routinely obtained percutaneous access themselves. Reasons for this trend may include lack of training, comfort level and perceived need for radiological involvement. In this study we evaluated percutaneous access for percutaneous nephrolithotomy obtained by interventional radiologists or a urologist at a single academic institution, and compared access trends and complications. MATERIALS AND METHODS: Two cohorts of patients who had undergone percutaneous nephrolithotomy between 1999 and 2003 were reviewed. Percutaneous access was performed by a group of interventional radiologists (group 1) or a urologist (group 2). An access difficulty score was calculated using patient, stone and procedural variables. Primary outcome measures of percutaneous access complications such as bleeding, failure of access, pneumothorax or other organ injury were compared between groups. Secondary outcome measures of stone-free rates were also compared. RESULTS: In groups 1 and 2, 54 and 49 patients were identified with a total number of tracts of 54 and 60, respectively. Both groups had similar rates of supracostal access. Mean access difficulty scores were similar between groups. Access related complications were significantly higher in the radiology access group (15 vs 5). Stone-free rates were significantly better in the urology access group (86% vs 61%). CONCLUSIONS: Despite similar access difficulty between groups, access related complications were less and stone-free rates were improved during urologist acquired percutaneous access. Urologists instructed in percutaneous access may be able to provide improved stone-free rates during percutaneous nephrolithotomy while minimizing access related complications.

Academic Medical Centers↗

PubMed2005

Design of functional simulation of renal cancer in virtual reality environments.

OBJECTIVES: The preoperative planning of partial nephrectomy can be facilitated by the ability to view the tumor and surrounding tissue in three-dimensional (3D) virtual reality (VR). A technique to convert Digital Imaging and Communications in Medicine computed tomography scan data into a fully 3D VR environment was developed. The model can be transferred to a personal computer, allowing the surgeon to view the 3D model in the operating room. METHODS: Computed tomography data from a patient with multifocal renal masses was converted into a 3D polygonal mesh using Amira running on a desktop personal computer with Windows XP Professional. A Silicon Graphics Monster Onyx2 running the Linux operating system was used to view the 3D stereo model in the VR environments: either the CAVE or a specialized desk called the Immersadesk. An application to view and interact with the model on a desktop personal computer was written in C++. RESULTS: A 3D model of the kidney, the multiple tumors, and the associated systems was created. The model could be viewed and manipulated in a true VR environment and on a desktop personal computer. CONCLUSIONS: This project completed two major goals. First, a 3D model of a kidney containing multiple masses was created and viewed in a VR environment. Second, an interface to display the model on a desktop personal computer in the operating room was created. This is the first step in bringing VR technology to the operating room to assist the surgeon directly.

Aged↗

PubMed2004

Surface-enhanced laser desorption/ionization-time of flight-mass spectrometry (SELDI-TOF-MS): a new proteomic urinary test for patients with urolithiasis.

SELDI-TOF-MS is a highly sensitive protein-analysis tool capable of detecting minute protein profile differences between biological samples. As proteins have been associated with urinary tract calculi, protein-based urinalysis may offer insights into their diagnosis. The purpose of this study was to evaluate SELDI-TOF-MS as a potential method for identifying urinary biomarkers of urolithiasis. Midstream sterile urine samples were obtained from 25 male patients with a confirmed diagnosis of urolithiasis (test group) and 25 male subjects with no known history of the disease (controls). Urinary levels of oxalate, total protein, albumin, and osteopontin were determined. Protein profiles were generated using SELDI-TOF-MS.SELDI-TOF-MS profiling revealed a relationship between protein peak intensities at 67 and 24 kDa that differed between the two groups. The ratio of p67:p24 was found to be less than 1.0 in all of the control samples (mean 0.26), while 18 out of 25 (72%) of the test group samples displayed a ratio greater than 1.0 (total group mean 4.75, P<0.001). Albumin, total protein, and oxalate levels were higher in the test group than the controls. Although SELDI-TOF-MS is not yet in widespread use in hospital and diagnostic laboratories, this system represents a promising new method for rapidly identifying patients with urolithiasis.

Albumins↗

PubMed2004

Percutaneous antegrade endopyelotomy: long-term results from one institution.

OBJECTIVES: To assess the long-term efficacy of percutaneous antegrade endopyelotomy for the treatment of ureteropelvic junction (UPJ) obstruction performed at a single institution during a 10-year period. We provide alterations in investigation and management strategies on the basis of the results. METHODS: From July 1990 to June 2001, 80 patients with clinical and radiographic evidence of UPJ obstruction underwent percutaneous endopyelotomy for the treatment of primary (n = 61) or secondary (n = 19) UPJ obstruction. The mean patient age was 35 years (range 4 to 76). Percutaneous endopyelotomy was performed in a standard fashion using either a hooked-knife (n = 77) or holmium laser (n = 3). RESULTS: With a mean patient follow-up of 55 months (range 16 to 138), the overall success rate was 67% (53 of 79). The success rate for primary and secondary UPJ obstruction was 65% (39 of 60) and 74% (14 of 19), respectively. The mean time to failure was 15 months (range 1 to 79). Operative intervention for 24 of 26 patients with failure included open pyeloplasty (n = 18, 75%), indwelling ureteral stenting (n = 2, 8%), retrograde balloon dilation (n = 1, 4%), and nephrectomy (n = 3, 13%). Two asymptomatic patients with recurrent radiographic evidence of obstruction elected conservative follow-up. Significant crossing vessels were encountered at open pyeloplasty in 15 (83%) of 18 patients. CONCLUSIONS: Our long-term results of percutaneous endopyelotomy demonstrated somewhat lower success rates than that reported in published studies. Long-term follow-up is critical in identifying late failures. The high prevalence of crossing vessels encountered at open pyeloplasty provided further evidence to support its role in endopyelotomy failure. Routine preoperative helical computed tomography to detect significant crossing vessels is recommended. Patients with crossing vessels are likely better served with operative techniques that specifically address this issue, namely open or laparoscopic pyeloplasty.

Adolescent↗

PubMed2004

Double-blind randomized controlled trial assessing the safety and efficacy of intravesical agents for ureteral stent symptoms after extracorporeal shockwave lithotripsy.

BACKGROUND AND PURPOSE: Ureteral stents are a significant source of pain and discomfort for many urologic patients. A novel approach to addressing this problem is the intravesical instillation of a selected pharmacologic agent after stent insertion. The purpose of this study was to assess the safety and efficacy of intravesical instillation of various agents in reducing ureteral stent-associated discomfort in patients requiring a stent after extracorporeal shockwave lithotripsy (SWL). PATIENTS AND METHODS: In this double-blind prospective trial, 42 patients were randomized to receive intravesical instillation of one of three agents (oxybutynin, alkalinized lidocaine, or ketorolac) or a control solution (0.9% sodium chloride) immediately after stent insertion at time of SWL. The four groups of patients were demographically similar. Preoperative, intraoperative, and postoperative data were collected prospectively and analyzed statistically. The primary outcome measure was reduction in ureteral stent symptoms, and the secondary outcome measure was the safety of intravesical instillation of each agent through assessment of drug-related adverse events. RESULTS: There were no intraoperative or postoperative complications, nor were there any serious side effects attributable to any of the intravesically instilled agents. There was a statistically significant decrease in stent-related discomfort at the 1-hour time point in the group of patients who received intravesical ketorolac compared with the control group. CONCLUSIONS: Intravesical instillation represents a novel approach to the problem of ureteral stent-related discomfort. From our results, ketorolac appears to be the most effective intravesical agent in reducing stent-related patient discomfort, and we have established that intravesical instillation of ketorolac is safe in humans.

Administration, Intravesical↗

PubMed2004

Urinary tract biomaterials.

PURPOSE: As a result of endourological advances, biomaterials have become increasingly used within the urinary tract. This review article provides an update on the current status of urinary tract biomaterials, discussing issues of biocompatibility, biomaterials available for use, clinical applications and biomaterial related complications. Perspectives on future materials for use in the urinary tract are also provided. MATERIALS AND METHODS: We performed a comprehensive search of the peer reviewed literature on all aspects of biomaterials in the urinary tract using PubMed and MEDLINE. All pertinent articles were reviewed in detail. RESULTS: Any potential biomaterial must undergo rigorous physical and biocompatibility testing prior to its commercialization and use in humans. There are currently many different bulk materials and coatings available for the manufacturing of biomaterials, although the ideal material has yet to be discovered. For use in the urinary tract, biomaterials may be formed into devices, including ureteral and urethral stents, urethral catheters and percutaneous nephrostomy tubes. Despite significant advances in basic science research involving biocompatibility issues and biofilm formation, infection and encrustation remain associated with the use of biomaterials in the urinary tract and, therefore, limit their long-term indwelling time. CONCLUSIONS: Prosthetic devices formed from biomaterials will continue to be an essential tool in the practicing urologist's armamentarium. Ongoing research is essential to optimize biocompatibility and decrease biomaterial related complications such as infection and encrustation within the urinary tract. Future advances include biodegradables, novel coatings and tissue engineering.

Biocompatible Materials↗

PubMed2003

Biomaterials in urology.

Biomaterials such as urethral catheters, urethral stents, and ureteral stents are commonly used in patients with urologic disorders. There are currently many different bulk materials and coatings available for the manufacture of urinary tract biomaterials; however, the ideal material has yet to be discovered. Any potential biomaterial must undergo rigorous physical and biocompatibility testing before commercialization and use in humans. Despite significant advances in basic science research involving biocompatibility issues and biofilm formation, infection and encrustation remain associated with the use of biomaterials in the urinary tract, and therefore, limit their long-term use. This review critically evaluates the literature published over the past 12 months, providing an update on the current status of naturally derived and synthetic polymeric biomaterial use in the urinary tract. We focus on urethral catheters, urethral stents, and ureteral stents. We discuss issues of biocompatibility and new approaches to biocompatibility testing, biomaterials currently available for use, new biomaterials and coatings, and novel ureteral stent designs. Finally, we discuss the future of biomaterial use in the urinary tract.

Biocompatible Materials↗

PubMed2003

Oxalate-degrading enzymes from Oxalobacter formigenes: a novel device coating to reduce urinary tract biomaterial-related encrustation.

BACKGROUND AND PURPOSE: The long-term placement of biomaterials within the urinary tract is limited by the development of encrustation. In a noninfected urinary environment, encrustation often results from the deposition of calcium oxalate on the biomaterial surface. There is an association between the absence of Oxalobacter formigenes, a commensal colonic bacterium capable of degrading oxalate, and calcium oxalate stone formation. This pilot study was designed to evaluate several oxalate-degrading enzymes produced by O. formigenes as a potential biomaterial coating to reduce urinary tract encrustation. MATERIALS AND METHODS: Circular silicone disks of 6-mm diameter were incubated for 48 hours in oxalylcoenzyme A decarboxylase (OXC), formyl-coenzyme A transferase (FRC), and coenzyme A, while control disks were incubated in distilled water. The adsorption of OXC and FRC was assessed using enhanced chemiluminescence (ECL) and atomic force microscopy (AFM). Coated and uncoated disks (20 of each) were implanted in the bladders of 40 female New Zealand White rabbits. After 30 days, the disks were recovered, and the degree of encrustation on the polymer surface was evaluated utilizing dry weight measurement, calcium atomic absorption spectroscopy (AAS), and scanning electron microscopy/energy-dispersive X-ray analysis (SEM/EDX). RESULTS: Both ECL and AFM demonstrated coating of the silicone disks with OXC and FRC. The mean dry weights of the coated and control disks following explantation were 0.591 +/- 0.438 g and 0.747 +/- 0.428 g, respectively (P = 0.307). The mean weight of calcium on the coated and control disks, as determined by AAS, was 154.1 +/- 96.25 mg and 258 +/- 181.35 mg, respectively (P = 0.008). CONCLUSIONS: The use of oxalate-degrading enzymes from O. formigenes to coat urinary biomaterials represents a novel paradigm to reduce biomaterial-related encrustation. Coating of silicone with oxalate-degrading enzymes from O. formigenes results in a modest reduction in encrustation with no apparent toxicity. Further studies are warranted.

Animals↗

PubMed2003

Swarming of Proteus mirabilis over ureteral stents: a comparative assessment.

BACKGROUND AND PURPOSE: Encrustation on indwelling ureteral stents is commonly related to the presence of urease-producing bacteria that elevate the pH of the urine through the hydrolysis of urea, resulting in the precipitation of calcium and magnesium salts. Using a model previously shown to measure accurately the ability of Proteus mirabilis to swarm over catheter surfaces (Eur J Clin Microbiol Infect Dis 1999;18:206), we investigated the ability of this organism to swarm over three ureteral stents with potential encrustation-resistance properties. MATERIALS AND METHODS: Three commercially available ureteral stents were selected for evaluation: a low surface-energy stent, a hydrogel-coated stent, and a silicone stent. Ten-microliter aliquots of a 4-hour culture of P. mirabilis 296 in Trypticase soya (TSA) broth was inoculated 5 mm from a 1-cm channel cut out from TSA plates. Ten-millimeter stent sections were placed as bridges across the central channel adjacent to the inocula. Time to pathogen crossing was measured. RESULTS: The mean time (+/- SD) to pathogen migration across the three test materials was 15.9 +/- 6.1, 19.8 +/- 9.5, and 29.7 +/- 14.3 hours for the low surface-energy, hydrogel-coated, and silicone stents, respectively. Statistical analysis revealed significant differences between the crossing times of the low surface-energy (P = 0.001) and hydrogel-coated (P = 0.034) stents compared with silicone but not between the low surface-energy and hydrogel-coated stents (P = 0.387). CONCLUSION: Migration of P. mirabilis 296 across silicone stents was significantly reduced compared with low surface-energy and hydrogel-coated stents. These findings suggest that P. mirabilis may have a lower affinity for silicone stents, which may translate into a reduced risk of infection with P. mirabilis and associated stent encrustation.

Equipment Contamination↗

PubMed2003

Use of a temporary ureteral drainage stent after uncomplicated ureteroscopy: results from a phase II clinical trial.

PURPOSE: An indwelling ureteral stent is commonly placed for 48 hours after uncomplicated ureteroscopy to maintain drainage and prevent postoperative complications. A propriety temporary ureteral drainage stent (TUDS, Boston Scientific/Microvasive, Natick, Massachusetts) was developed to satisfy this goal with the added advantages of biodegradability and spontaneous passage. We evaluated TUDS performance in a patient population. MATERIALS AND METHODS: A total of 88 patients at 6 centers were selected for TUDS placement. Device safety as well as effectiveness, defined as adequate intervention-free drainage for 48 hours with the maintenance of ureteral position, were the primary study end points. Secondary end points consisted of the time required to eliminate TUDS from the body, tolerability of device presence and passage, and overall patient satisfaction with the stent. RESULTS: A single patient was excluded from primary end point analysis because of inadequate day 2 evaluation, resulting in an overall stent effectiveness rate of 78.2% (68 of 87 patients). Primary end point failure occurred in the remaining 19 patients (21.8%) with early stent extrusion in 17 and intervention required in 2 others within 48 hours of stent placement (cystoscopy and intravenous analgesia in 1, and intravenous analgesia alone in 1). There were no adverse clinical sequelae in 16 patients who experienced early extrusion with only 1 requiring intravenous pain medication. Stent fragments were retained beyond 3 months in 3 patients, of whom 2 were treated in a minimally invasive manner with shock wave lithotripsy, while 1 required ureteroscopy and shock wave lithotripsy to clear the residual fragments. Median time to stent elimination from the ureter and from the body was 8 and 15 days, respectively. Overall 71 of the 80 patients (89%) reported satisfaction with TUDS. CONCLUSIONS: The concept of a self-degrading internal ureteral stent represents a new paradigm in ureteral drainage. TUDS combines adequate ureteral drainage and patient satisfaction after uncomplicated ureteroscopy, eliminating the need for stent removal.

Adolescent↗

PubMed2003

Percutaneous management of calculi within horseshoe kidneys.

PURPOSE: Percutaneous treatment of patients with calculi in a horseshoe kidney can be challenging due to the altered anatomical relationship in the retroperitoneum. Therefore, we performed a multi-institutional review to assess the safety and efficacy of this minimally invasive technique. MATERIALS AND METHODS: Of 37 patients identified with calculi in a horseshoe kidney at 3 institutions 24 (65%) underwent percutaneous nephrolithotripsy as primary treatment. Average patient age was 48.4 years and 75% of the patients were male. In 3 patients with staghorn calculi mean stone size as measured by computed digitized stone surface area was 448 mm2. Mean followup was 5.8 months. The stone-free rate, complication rate, need for secondary intervention and stone composition were evaluated. RESULTS: Renal access was obtained through an upper pole calix in 63% of the cases, a lower calix in 25% and a middle calix in 4%. Access location was not documented in 1 patient (4%). Of the 24 patients 21 (87.5%) were rendered stone-free after primary or second look procedures. Flexible nephroscopy was used in 84% of cases. Minor complications occurred in 4 patients (16.7%), whereas 3 (12.5%) experienced major complications, including significant bleeding necessitating early cessation, nephropleural fistula and pneumothorax. No deaths occurred as a result of this treatment choice. Stone analysis was available for 21 cases (87.5%). Calcium stones predominated (87.5%), followed by uric acid (9.5%) and struvite (4.8%). CONCLUSIONS: Percutaneous treatment of patients with renal calculi in a horseshoe kidney is technically challenging, usually requiring upper pole access and flexible nephroscopy due to the altered anatomical relationships of the fused renal units. The success rate based on stone-free results and a relatively low incidence of major complications suggest that this minimally invasive management option is an effective means of stone management in this complex patient population.

Adult↗

PubMed2003

Group A streptococcal hydrocele infection and sepsis in a renal transplant recipient.

A case of hydrocele infection secondary to a cutaneous b-hemolytic group A streptococcal infection is described in a renal transplant recipient. Sepsis and renal failure occurred in the setting of this severe, life-threatening infection. This case represents the first description of a group A streptococcal hydrocele infection in an adult. This type of infection can progress rapidly to sepsis and its attendant complications, especially in an immunocompromised patient. Early diagnosis and treatment is crucial in order to optimize the outcome.

Adult↗

PubMed2003

Upper tract imaging after ureteroscopic holmium:YAG laser lithotripsy: when is it necessary?

INTRODUCTION/OBJECTIVE: Advances in ureteroscope design and refinements of ancillary instrumentation have resulted in an expanded role for ureteroscopy in the management of urinary calculi. Technological enhancements coupled with improved endourologic skills have also been associated with a reduction in procedural-related complications. Historically, postoperative imaging with ultrasound (U/S) or intravenous pyelogram (IVP) had been advocated to rule out persistent obstruction due to retained stone fragments or ureteral stricture. The purposes of this study were to evaluate the incidence of postoperative ureteral obstruction in a contemporary series of patients undergoing ureteroscopic holmium:YAG laser lithotripsy without basket extraction of fragments and to identify patient, stone and operative factors predictive of which patients will benefit from postoperative imaging. MATERIALS AND METHODS: The charts and imaging studies of 89 consecutive patients undergoing a total of 94 holmium:YAG ureteroscopic lithotripsy procedures between December 1998 and December 2000 were retrospectively reviewed. Preoperative, intraoperative and postoperative data were collected and analyzed. The primary outcome measure was the incidence of postoperative ureteral obstruction documented on upper tract imaging. Secondary outcome measures included interventions required for postoperative obstruction and other nonobstructive postoperative complications. RESULTS: Twenty-eight females and 61 males were studied, with a mean patient age of 54 (range 13-80) years. Fifty-five percent of patients underwent related procedures prior to referral to our tertiary endourology centre. Complete clinical and radiological follow-up is available for 68 of 89 (76.4%) patients, with a mean follow-up duration of 24.2 weeks. Overall stone-free rate was 97%. Six patients had evidence of urinary tract obstruction on follow-up radiological assessment, two from residual stone fragments and four from ureteral stricture. Each of these four patients had at least one preoperative risk factor for ureteral stricture. CONCLUSIONS: Routine postoperative upper tract imaging is not necessary in all patients undergoing uncomplicated ureteroscopic holmium:YAG laser lithotripsy. Indications for upper tract imaging include chronic stone impaction, significant ureteral trauma, pre-existing renal function impairment, endoscopic evidence of stricture and postoperative flank pain or fever.

Adolescent↗

PubMed2002

Randomized prospective blinded study validating acquistion of ureteroscopy skills using computer based virtual reality endourological simulator.

PURPOSE: Surgical simulation has emerged in the last decade as a potential tool for aiding acquisition of technical skills, including anesthesia protocols, trauma management, cardiac catheterization and laparoscopy. We evaluate and validate the use of a computer based ureteroscopy simulator (URO Mentor, Simbionix Ltd., Lod, Israel) in the acquisition of basic ureteroscopic skills. MATERIALS AND METHODS: We assessed 20 novice trainees for the ability to perform basic ureteroscopic tasks on a computer based ureteroscopy simulator. Participants were randomized to receive individualized mentored instruction or no additional training, and subsequently underwent post-testing. Pre-training and post-training improvement in performance was assessed by objective simulator based measurements. Subjective overall performance was rated using a validated endourological global rating scale by an observer blinded to subject training status. RESULTS: Demographics and pre-test scores were similar between groups. Post-testing revealed a significant effect of training on objective and subjective measurements. Spearman rank correlation demonstrated a significant association between objective simulator based measurements and the endourological global rating scale. CONCLUSIONS: Use of a computer based ureteroscopy simulator resulted in rapid acquisition of ureteroscopic skills in trainees with no prior surgical training. Results of this study demonstrate the use of a virtual reality ureteroscopy simulator in endourological training. Correlation of simulator based measurements with a previously validated endourological global rating scale provides initial validation of the ureteroscopy simulator for the assessment of ureteroscopic skills.

Adult↗

PubMed2002

Safety and efficacy of holmium: YAG laser lithotripsy in patients with bleeding diatheses.

PURPOSE: We assessed the safety and efficacy of ureteroscopy and holmium:YAG laser lithotripsy for treating upper urinary tract calculi in patients with known and uncorrected bleeding diathesis. MATERIALS AND METHODS: We retrospectively reviewed the charts at 2 tertiary stone centers to identify patients with known bleeding diathesis who were treated with holmium:YAG laser lithotripsy for upper urinary tract calculi. A total of 25 patients (29 upper urinary tract calculi) underwent ureteroscopic holmium laser lithotripsy. Bleeding diathesis involved warfarin administration for various conditions in 17 patients, liver dysfunction in 3, thrombocytopenia in 4 and von Willebrand's disease in 1. The mean international normalized ratio, platelet count and bleeding time were 2.3, 50 x 109/l. and greater than 16 minutes in patients on warfarin and in those with liver dysfunction, thrombocytopenia and von Willebrand's disease, respectively. RESULTS: Overall the stone-free rate was 96% (27 of 28 cases) and 29 of 30 procedures were completed successfully without significant complication. In a patient treated concomitantly with electrohydraulic lithotripsy significant retroperitoneal hemorrhage required blood transfusion. CONCLUSIONS: Upper tract urinary calculi in patients with uncorrected bleeding diathesis can be safely managed by contemporary small caliber ureteroscopes and the holmium laser as the only modality of lithotripsy. Ureteroscopic holmium laser lithotripsy without preoperatively correcting hemostatic parameters limits the risk of thromboembolic complications and costs associated with an extended hospital stay. Avoiding electrohydraulic lithotripsy is crucial for decreasing bleeding complications in this cohort of patients.

Adult↗

PubMed2002

Holmium:YAG laser lithotripsy for upper urinary tract calculi in 598 patients.

PURPOSE: We assessed the effectiveness and safety of holmium:YAG laser lithotripsy for managing upper urinary tract calculi in a prospective cohort of 598 patients. MATERIALS AND METHODS: Ureteroscopic holmium:YAG laser lithotripsy was performed in 598 patients between 1993 and 1999. Calculi were located in the distal ureter in 39.6% of cases, mid ureter in 18.6%, proximal ureter in 32.4% and kidney in 9.4%. Patients were treated on an outpatient basis with various flexible and semirigid endoscopes. Of the cases 59% were referred as previous treatment failures. Patients were assessed 6 to 12 weeks postoperatively with repeat plain x-ray and ultrasound or excretory urography for late obstructive complications. RESULTS: The overall stone-free rate was 97%. As stratified by location, the stone-free rate was 98% in the distal ureter, 100% in the mid ureter, 97% in the proximal ureter and 84% in the kidney. Fragmentation was incomplete in 6% of cases and secondary intervention was required in 6%. The overall complication rate was 4%. New onset ureteral stricture developed postoperatively in 0.35% of patients. CONCLUSIONS: Holmium:YAG laser lithotripsy is a highly effective and safe treatment modality for managing ureteral and a proportion of intrarenal calculi on an outpatient basis. The effectiveness and versatility of the holmium laser combined with small rigid or flexible endoscopes make it our modality of choice for ureteroscopic lithotripsy.

Adolescent↗

PubMed2002

Ureteroscopy and holmium:YAG laser lithotripsy: an emerging definitive management strategy for symptomatic ureteral calculi in pregnancy.

OBJECTIVES: To review the results of holmium laser lithotripsy in a cohort of patients who presented with symptomatic urolithiasis in pregnancy. Symptomatic urolithiasis in pregnancy that does not respond to conservative measures has traditionally been managed with ureteral stent insertion or percutaneous nephrostomy. Holmium:yttrium-aluminum-garnet (YAG) laser lithotripsy using state-of-the-art ureteroscopes represents an emerging strategy for definitive stone management in pregnancy. METHODS: A retrospective analysis was conducted at two tertiary stone centers from January 1996 to August 2001 to identify pregnant patients who were treated with ureteroscopic holmium laser lithotripsy for symptomatic urolithiasis or encrusted stents. Eight patients with a total of 10 symptomatic ureteral calculi and two encrusted ureteral stents were treated. The mean gestational age at presentation was 22 weeks. The mean stone size was 8.1 mm. The stones were located in the proximal ureter/ureteropelvic junction (n = 3), midureter (n = 1), and distal ureter (n = 6). RESULTS: Complete stone fragmentation and/or removal of encrusted ureteral stents were achieved in all patients using the holmium:YAG laser. The overall procedural success rate was 91%. The overall stone-free rate was 89%. No obstetric or urologic complications were encountered. CONCLUSIONS: Ureteroscopy and holmium laser lithotripsy can be performed safely in all stages of pregnancy, providing definitive management of symptomatic ureteral calculi. The procedure can be done with minimal or no fluoroscopy and avoids the undesirable features of stents or nephrostomy tubes.

Adult↗

PubMed2002

Holmium: YAG laser endoureterotomy for ureterointestinal strictures.

PURPOSE: The management of ureterointestinal stricture in patients who have undergone urinary diversion can be challenging. Endourological techniques have been increasingly used in recent years for ureteral stricture. While long-term results may not be as reliable or durable as those of traditional open reconstructive surgical techniques, associated morbidity is much less. The holmium (Ho):YAG laser, which has cutting and coagulating properties, has been demonstrated to have many applications in urology. We report our experience with and long-term results of Ho:YAG laser endoureterotomy for ureterointestinal strictures. MATERIALS AND METHODS: We reviewed the charts and followup history of 23 patients in whom the Ho:YAG laser was used to treat ureterointestinal anastomotic stricture. Strictures were treated percutaneously via the antegrade approach with flexible endoscopes and the holmium laser. A reversed 12/6Fr endopyelotomy stent was left indwelling for 6 weeks postoperatively. Success was defined as symptomatic improvement and radiographic resolution of obstruction. RESULTS: Between 1993 and 2000, 23 patients with a mean age of 61 years underwent endo-ureterotomy using the Ho:YAG laser for 24 ureterointestinal stricture. An overall success rate of 71% (17 of 24 cases) was achieved at a mean followup of 22 months. The success rate of holmium laser endoureterotomy for ureterointestinal stricture at 1, 2 and 3 years was 85%, 72% and 56%, respectively. Seven patients had recurrent strictures of which 4 developed 16 months or more postoperatively. No complications were noted. CONCLUSIONS: Ho:YAG laser endoureterotomy for ureterointestinal stricture disease is a minimally invasive endourological procedure that may provide more durable results than other modalities used for endoureterotomy. The Ho:YAG laser with its ability to cut tissue precisely and provide hemostasis combined with its versatility and compatibility with flexible endoscopes is an ideal instrument for safely performing endoureterotomy.

Adult↗