First clinical evaluation of a new single-use flexible cystoscope dedicated to double-J stent removal (Isiris™): a European prospective multicenter study.

PURPOSE: We evaluated a new single-use digital flexible cystoscope with an integrated grasper designed for double-J stent removal, Isiris™, addressing success rate, image quality, deflection, maneuverability and grasper functionality. METHODS: In September 2015, a prospective cohort study was conducted in six tertiary European reference centers. All consecutive patients included underwent double-J stent removal and were 18 years or older. Success rate was defined by complete stent removal. Image quality, deflection, maneuverability and grasper functionality were rated with a Likert scale. RESULTS: A total of 83 procedures were performed. 82% of procedures were performed in the endoscopy room, while the others were in the operating room since a consecutive endourological intervention was planned. The median duration of stent implantation was 28 days [14; 60]. In five patients, stent removal was not possible. Four patients had an incrusted double-J stent, and in one patient, the stent migrated into the ureter. After unsuccessful attempts of stent removal with conventional flexible cystoscope and grasper, the five patients had to be scheduled for an ureterorenoscopy procedure to remove the stent. In the other 78 patients, all double-J stents were removed successfully. Image quality, deflection, maneuverability and grasper functionality were rated as "very good" in 72.3, 78.3, 72.3 and 73.5%, respectively. CONCLUSION: This multicenter clinical evaluation of Isiris™ displayed good image quality, active deflection, maneuverability and grasper functionality. Further evaluation of stent removal outcomes, cost analysis and microbiology will help to delineate the possible place of Isiris™ in the current practice.

Comparative study for the efficacy and safety of percutaneous nefhrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS) for the treatment of 2-3,5 cm kidney stones. / Estudio comparativo de eficacia y seguridad de la nefrolitotomía percutánea (NLPC) y la cirugía retrógrada intrarrenal (CRIR) para litiasis renales de 2-3,5 cm.

OBJECTIVES: Retrograde intrarenal surgery (RIRS) has become an important alternative for the treatment of kidney stones due to its increased safety and efficiency. The purpose of this study is to compare efficacy and safety features of RIRS against percutaneous nephrolithotomy (PCNL) for the treatment of 2 - 3.5 cm kidney stones. METHODS: 142 cases (106 RIRS and 36 PCNL) encompassing 2 - 3.5 cm kidney stones that have been treated in our center between December 2009 and December 2011 have been considered. Demographic variables, stone characteristics, surgical stay and surgical time have been evaluated. Additionally, the complication prerate and success rate after one and two procedures (retreatment) have also been assessed. Student's T, Mann-Whitney U y Chi² - V Cramer (p=0.05) tests were used for statistical analysis. RESULTS: There are not statistically significant differences in demographic or stone variables. The calculated mean surgical time was lower for PCNL (85 min) than for RIRS (112 min). Mean hospital stay was statistically significantly shorter in RIRS (16 h vs. 98 h in RIRS, p=0.001). PCNL exhibited a higher global complication rate of 19.4% vs. 6.6% for RIRS (p=0.001). PCNL also showed a higher successful rate (80.6% vs. 73.6% for RIRS), although this difference was not statistically significant (p=0.40). When comparing the success rate after a second procedure, PCNL results in 94.3% vs. 93.5% for RIRS (p=0.88). CONCLUSION: RIRS was found to be a safe and efficient procedure with a short hospital stay. Overall, RIRS can be considered as an alternative to PCNL for the treatment of renal stones smaller than 3.5 cm.

A pilot experience launching a national dose protocol for vascular and interventional radiology.

The design of a national dose protocol for interventional radiology has been one of the tasks during the European SENTINEL Coordination Action. The present paper describes the pilot experience carried out in cooperation with the Spanish Society on Vascular and Interventional Radiology (SERVEI). A prospective sample of procedures was initially agreed. A common quality control of the X-ray systems was carried out, including calibration of the air kerma area product (KAP) meters. Occupational doses of the radiologists involved in the survey were also included in the survey. A total of 10 Spanish hospitals with interventional X-ray units were involved. Six hundred and sixty-four patient dose data were collected from 397 diagnostic and 267 therapeutic procedures. Occupational doses were evaluated in a sample of 635 values. The obtained KAP median/mean values (Gy.cm2) for the gathered procedures were: biliary drainage (30.6/68.9), fistulography (4.5/9.8), lower limb arteriography (52.2/60.7), hepatic chemoembolisation (175.8/218.3), iliac stent (45.9/73.2) and renal arteriography (39.1/59.8). Occupational doses (mean monthly values, in mSv) were 1.9 (over apron); 0.3 (under apron) and 4.5 (on hands). With this National experience, a protocol was agreed among the SENTINEL partners to conduct future similar surveys in other European countries.

Field use of N-butylscopolammonium bromide to facilitate thorough ophthalmic examination in horses.

N-butylscopolammonium bromide (NBB), an anticholinergic muscarinic antagonist, was assessed as a mydriatic agent for field examination of equine eyes. Six adult horses were randomly assigned to four treatments with 2 weeks washout between treatments: (1) topical saline/IV saline (negative control); (2) topical tropicamide/IV saline (positive control); (3) topical NBB/IV saline; or (4) topical saline/IV NBB. Horizontal and vertical pupil diameters, temperature, pulse, respiration, pupillary light reflexes (PLRs) and mydriasis sufficient to perform complete fundic examination were recorded. Tropicamide induced mydriasis in all horses. Topical NBB induced mydriasis in one horse, and IV NBB enabled thorough fundic examination in two horses, delayed PLRs without allowing thorough examination in two horses and had no effect in two horses.

[Endoluminal percutaneous thrombectomy as a treatment for acute vascular access thrombosis: long-term results of 123 procedures]. / La trombectomía endoluminal percutánea como tratamiento de la trombosis aguda del acceso vascular: resultados a largo plazo de 123 procedimientos.

UNLABELLED: Percutaneous treatment of thrombosis of occluded vascular access (VA) for haemodialysis (HD) has been an alternative to surgical and pharmacological treatments, but long term results are not well defined. The aim of our study was to analyse the long term results of percutaneous thrombectomy as a treatment of occluded VA for HD. We conducted a prospective study from june 1995 to april 1999, including 123 consecutive thrombectomies in 64 VA in patients submitted to our hospital because of recent thrombosis of VA for HD. We used two different techniques, hydrodynamic catheter thrombectomy (Hydrolyser) in the 42 first procedures (34.1%), and since october 1996 we used mechanical balloon thrombolysis in the remaining 81 patients (65.9%). Underlying stenoses were evaluated by angiography, and treated by angioplasty. After the procedure, intravenous heparin was administered for 24 hours. The VA were 28 Brescia-Cimino arteriovenous fistulae (30.4%) and 64 PTFE grafts (69.6%). PATIENT CHARACTERISTICS: mean age: 63 +/- 15 years (18-84), previous VA: 3.3 +/- 2.5 (0-9). The mean follow-up was 10.5 +/- 8.6 months (3-35). Percutaneous thrombectomy was able to remove the clots in 120 instances (technical success: 97.5%). After the thrombectomy 15 patients (16.3%) were immediately referred to the surgeon to perform a new VA due to vascular lesions in which percutaneous treatment was not indicated. Thirteen cases (14.1%) showed early thrombosis (< 72 hours). During the follow-up, 27 cases developed thrombosis (30%) and 26 VA were still patent (28.3%). In 23% of perfusion lung scans and in 2 of the 5 angiographies performed after thrombectomy, subsegmentary or segmentary perfusion defects were detected, without clinical significance. There were no relevant undesirable effects related to the technique and no symptomatic pulmonary embolism. In summary, percutaneous thrombectomy, whether hydrodynamic or mechanical, has shown to be an efficacious treatment of VA thrombosis for HD, preserving the VA with satisfactory long-term results.

Hepatic and splanchnic perfusion and oxygenation after transjugular intrahepatic portosystemic shunt.

OBJECTIVE: in patients with cirrhosis, transjugular intrahepatic portosystemic shunt (TIPS) decreases the pressure in the portal vein by rerouting nearly all the portal blood flow to the systemic circulation. This may lead to hypoperfusion of the liver and worsening function. Our aim was to investigate whether TIPS actually reduced hepatic and splanchnic perfusion. METHODS: we studied 25 patients who required placement of a TIPS (20 for variceal bleeding and 5 for refractory ascites). We evaluated the clinical condition, laboratory results, blood velocity in the portal vein and hepatic artery by echo-Doppler ultrasonography, systemic hemodynamic-oxygenation status and hemodynamic-oxygenation status in the portal and suprahepatic veins before TIPS, 15 min after the procedure, and 30 days later. Hepatic and splanchnic perfusion were evaluated as the arteriovenous difference in O2 content and as the O2 extraction rates in the hepatic and splanchnic territories. RESULTS: TIPS induced an immediate decrease in portal pressure, a significant increase in systemic hyperdynamic state, and an increase in blood flow velocity in the portal vein and hepatic artery. Thirty days after the procedure these changes persisted, although they were somewhat attenuated. Although splanchnic and liver perfusion were not changed 15 min or 30 days after TIPS, there was a slight tendency toward a decrease in liver perfusion during follow-up. CONCLUSIONS: TIPS increased the hyperdynamic state in the systemic side. However, portal blood shunting did not change liver or splanchnic perfusion.

[Intra-arterial fibrinolysis in acute thrombosis of the basilar artery]. / Fibrinólisis intrarterial en la trombosis aguda de la arteria basilar.

INTRODUCTION: Ischemia in the territory of the basilar artery presents with a variable clinical picture of hemiparesia-tetraplegia, progressive deterioration of level of consciousness, irregular respiration and apnea leading to irreversible coma and death in between 75% and 86% of cases. The usual treatment is supportive. CLINICAL CASE: We present the case of a 49 year old woman with acute thrombosis of the basilar artery and a progressive course leading to coma. No bulbar lesions were seen on the CT scan done in the Emergency Department. Thrombosis of the basilar artery and permeable bilateral carotid systems were shown on arteriography. There were no contra-indications to fibrinolysis. Following local fibrinolytic treatment with urokinase the patient had full recovery from her neurological disorder and no sequelae. The basilar artery remained permeable six months later. CONCLUSIONS: Emergency treatment with cerebral intra-arterial fibrinolysis within the first six hours, in a case of neurological deficit progressing in the basilar artery territory, with persistence of brain-stem functions and no signs of decerebration (provided there are no contra-indications to fibrinolysis and the initial cerebral CT scan shows no bulbar lesions) may save the patient's life, with total or partial recovery of brain-stem function.

[Percutaneous nephrostomy. Review of 92 cases]. / Nefrostomías percutáneas. Revisión de 92 casos.

Presentation of 92 nephrostomies percutaneous in 70 patients. Nephrostomy was bilateral in 5 cases. Three patients had collections of renal origin (2 urinomas and 1 abscess) which were treated percutaneously. The indication for nephrostomy was in all cases obstruction of the collector system, with one exception where the indication was ureteral fistula. Origin was lithiasis in 53 cases, 15 cases vesical carcinoma, 3 post-surgical iatrogenic stenosis, 1 fistula and formation of urinoma after lithotrity, 5 prostate carcinoma infiltration, 8 infectious origin, 4 congenital and 1 due to glandular cystitis. 9 patients were monorenal. In 6 patients leucocytosis was present, 4 has fever, and in 11 coexisted fever and leucocytosis. High creatinine and urea levels were present in 55.7% and 41% patients, respectively.. Renal puncture through lower calyceal group was the preferred option. Purulent urine was obtained in 17 cases. With regard to nephrostomy complications haematuria occurred in 30 cases (only in 9 it lasted more than 1 day); and there was 1 case of pararenal haematoma. Pain was significant in 12% procedures and contrast extravasation resulted in 14% cases (in all of them proper positioning of nephrostomy catheter was possible). Spontaneous expulsion and the subsequent replacement of the catheter occurred in 12 cases. On average, residence time of catheter was 44.8 days. In all cases both the patient's signs and symptoms, and the laboratory results were improved.

[Recurrent parotiditis in adults: review and new therapeutic options]. / Parotiditis recidivante en el adulto: revisión y nuevas alternatives terapéuticas.

Our experience in the management of 20 patients with recurrent parotitis (RP) as an isolated symptom is reported. The clinical manifestations in all patients were pain, infection and swelling of the parotid gland on at least three separate occasions. The presence of obvious tumor or specific inflammation were exclusion criteria. Three patients benefited from radiological interventional treatment: two stones were removed from the main duct with a Dormia basket and one parotid duct stricture was dilated with a balloon catheter. The role of conventional or digital sialography and interventional radiology procedures in the diagnosis and management of RP is discussed. We proposed this approach as a therapeutic alternative to surgery, which is more aggressive and carries a risk of facial nerve damage.

A comparative study of percutaneous nephrolithotomy in supine position and endoscopic combined intrarenal surgery with flexible instrument.

OBJECTIVE: To compare the results obtained in percutaneous nephrolithotomy after introduction of flexible ureteroscopy/nephroscopy (endoscopic combined intrarenal surgery - ECIRS) with nephrolitomies with only rigid nephroscopy (standard percutaneous nephrolithotomy; sPCNL). MATERIAL AND METHOD: A retrospective study of 171 sPCNL in Galdakao position performed between January 2005 and December 2011 was conducted. We compared the results obtained in those procedures in which endoscopic combined intrarenal surgery (ECIRS) was performed with those in which only the rigid nephroscopy (sPCNL) was used. Specific and global success, percentage of lithiasic load eliminated, days of hospital stay and complications derived were calculated. We defined success by complete absence of lithiasis or residual presence of<5mm. We differentiated specific success, that only achieved with percutaneous surgery, from global success, or that achieved after a second line of treatment. RESULTS: In 73 procedures (42.4%) ECIRS was performed with flexible endoscopy while in 98 (57.6%) it was done with sPCNL. Both groups were comparable in regards to demographic parameters and characteristics of the lithiasis. The success rates in the first procedure and global success were superior for the ECIRS group (75.3% vs 40.8% and 93.1% vs 74.5%), the differences being statistically significant (P<.05). No statistically significant differences were found in regards to the complications (28.8% vs 28.3% P=.86) or days of hospital stay (4.5 vs 5.0 P=.18). CONCLUSIONS: Use of the flexible ureteroscopy/nephroscopy in sPCNL (ECIRS) improves the success rates and elimination of lithiasic load, making it possible to perform the surgery with a single access in most of the cases.

A case control study on autopsy findings in sudden unexplained nocturnal death syndrome.

AIM: Sudden unexplained nocturnal death syndrome (SUNDS) has been linked to the Brugada syndrome. In some places, acute haemorrhagic pancreatitis is widely held to cause it. We conducted a systematic, controlled autopsy study on Filipino SUNDS victims to rule out structural heart findings as well as acute haemorrhagic pancreatitis as causes. METHODS AND RESULTS: A case control autopsy study was conducted comparing SUNDS victims between 18 and 50 years of age who died within 1 h of symptom onset with age- and gender-matched controls. There were 24 SUNDS (mean age 34.5 years) and 24 controls (mean 32.7 years). The autopsy incidence of structural heart disease was 8.3% (95% CI (1% to 27%)) and focal pancreatic haemorrhage was 4.17% (95% CI (0.1% to 20%)) but zero for true acute haemorrhagic pancreatitis among SUNDS victims. Autopsy findings in SUNDS versus controls were not significantly different from each other, showing no diagnostic abnormality in any of the organs. There was no significant difference in the incidence of acute haemorrhagic pancreatitis in both the SUNDS and control groups. We did not find fetal dispersion of the atrioventricular (AV) node, sclerosis or fibrosis of the AV conduction system, in a substudy of SUNDS cases. CONCLUSIONS: We have shown that there is no significant difference in the overall autopsy findings between SUNDS and controls. Autopsy findings were normal in 70% of SUNDS; no cardiac structural pathology was found in 87% of cases. Haemorrhagic pancreatitis is the cause of death in a minority of SUNDS. The cardiac conduction system is normal in a subgroup of SUNDS studied.

Results of retrograde intrarenal surgery in the treatment of renal stones greater than 2 cm.

OBJECTIVE: To analyze the results of retrograde intrarenal surgery (RIRS) in patients with ≥2 cm stones treated in our center. MATERIAL AND METHODS: A retrospective review of 106 patients with renal calculi underwent RIRS ≥2 cm (period January 2009-December 2011). The procedures were performed under general anesthesia as a source of fragmentation using the holmium laser (30 W Litho Quantasystem) and flexible ureteroscopes (X2 Flex Storz, Olympus P5) through ureteral access sheaths. It discusses demographic variables (age, medical history, antiplatelet or anticoagulant treatment, treatment of urolithiasis, BMI, ASA), treated stones variables (size, number, Hounsfield units, biochemical composition) and intra-and postoperative variables (operative time, number of pulses, hospital stay, complications) with the completion of a descriptive analysis of the same. To define our results we consider success to the complete absence of fragments or residual <5 mm posterior imaging tests. RESULTS: The mean stone size was 2.46 cm treated, being the only stone in 87.7% of cases. The most frequent location was the renal pelvis stones (44%) followed by the lower calyx (39%). The postoperative complication rate was 6.7%, with all of little relevance. The success rate with a single procedure was 79.4% to 94.1% with retreatment. CONCLUSION: RIRS is a valid alternative for the treatment of kidney stones ≥2 cm for its high success rate and few complications if performed in specialized centers.

[Analysis of predictive factors of success for prostate photovaporization in benign prostatic hyperplasia by greenlight laser]. / Análisis de factores predictivos de éxito para la fotovaporización próstatica en hiperplasia benigna de próstata mediante láser verde.

OBJECTIVE: To conduct a descriptive study of the implementation of greenlight laser photovaporization in a local hospital and to identify the ideal preoperative and intraoperative conditions to obtain a successful outcome. MATERIAL AND METHODS: A retrospective review of 179 photovaporizations performed between January 2007 and June 2010 was done. Preoperative data (age, prostate volume, PSA, IPSS, Qmax, medical history, ASA classification), intraoperative parameters (surgeon's experience, operating time, transfusion requirements, type of laser used, reconversion to transurethral resection of the prostate or TURP) and post-operative data (post-op complications, post-op PSA, post-op IPS score, post-op Qmax and reoperations) were analyzed. We performed a univariate and multivariate analysis to identify which preoperative and intraoperative parameters influence therapeutic failure. RESULTS: The descriptive study shows similarity in all parameters compared to the available literature. In the multivariate analysis, it was found that the surgeon's experience and prostate volume over 40 cc were independent predictive factors for success of greenlight laser photovaporization. CONCLUSIONS: Greenlight laser photovaporization is an effective and reproducible procedure for treating lower urinary tract obstruction due to benign prostatic hyperplasia (BPH). Multicenter, prospective and randomized studies are needed to confirm the results of this study. There are few studies available in the literature that provide a high level of evidence and grade of recommendation.

Study of predictive factors for complications after percutaneous nephrolithotomy according to the Clavien classification.

OBJECTIVE: Set predictors of complications in percutaneous nephrolithotomy (PCNL) using the modified Clavien system. MATERIAL AND METHODS: Retrospective study included 172 PCNL in Galdakao position made in the La Ribera Hospital between January 2005 and December 2011. They classified the complications of these procedures using the modified Clavien system. We performed a univariate analysis (Chi(2) Test and Cramer's V) and multivariate (logistic regression) of predictors of these complications (P < .05). RESULTS: In 49 of the 172 procedures complications were detected (28.5%).The most frequent complications were grade 1 (9.9%), 12 complications (6.9%) were classified as grade 2 by requiring additional medical treatment, 6 as grade 3A (3.5%), 7 as grade 3B (4.1%), 2 and 4A (1.1%), 4 and 4B (2.3%) and one and 5 (0.6%). In the univariate analysis, positive urine culture before surgery, the stones complex and larger than 40 mm of the same, showed a statistically significant association with the occurrence of complications (P < .05). The positive culture (OR: 2.96) and complex stones (OR: 3.03) proved to be independent variables predicting complications in multivariate analysis. CONCLUSIONS: Clavien system allows a common language for classifying complications, expressing the degree of the same as the complexity of treatment required for resolution. The preoperative urine culture positivity and complex stone proved predictors of these complications in our serie.

Treatment of hemorrhagic complications of percutaneous nephrolithotomy in Galdakao position.

OBJECTIVE: Percutaneous Nephrolithotomy (PCNL) is a technique with good results for the treatment of kidney stones, however, bleeding complications derived can be serious if not diagnosed and treated effectively. The aim of this study is to assess bleeding complications resulting from PCNL in Galdakao position and therapeutic management. MATERIAL AND METHODS: Retrospective-longitudinal study of 172 PCNL performed in La Ribera Hospital between January 2005 and December 2011, analyzing their bleeding complications and the treatment provided for resolution. RESULTS: Had bleeding complications 20 patients (11.6%). The need for transfusion in this series was 8.1% and the most common cause of blood transfusion the presence of postoperative retroperitoneal (7.5%). There were 6 arterial injuries (3.5%), 5 of them successfully treated with angiography and arterial selective embolization. CONCLUSIONS: The arterial injuries following PCNL are rare but can be serious. The possibility of an urgent arteriography and selective embolization to the diagnosis permits an effective and safe treatment of bleeding without risk to the affected renal unit.

[Surgical therapy of lithiasis in horseshoe kidney]. / Tratamiento quirúrgico de la litiasis en riñón en herradura.

OBJECTIVE: To present our centre's experience in the surgical treatment of lithiasis in patients with horseshoe kidney. MATERIAL AND METHODS: From October 2007 to March 2011 we treated 10 patients with renal lithiasis in their horseshoe kidneys. Retrospectively, we reviewed the symptoms, medical and surgical history, the characteristics of the stones (size, location, composition) and treatments that were carried out. In all the cases, the study was carried out by CT, with volume reconstruction and with an angiographic study. A percutaneous nephrolithotomy (PCNL) or an endoscopic retrograde intrarrenal surgery (RIRS) was carried out, depending on the size and location of the stone. RESULTS: Three percutaneous nephrolithotomies were carried out (2 on staghorn lithiasis stones, 1 pseudocoraliform stone) with a combined rigid and flexible single-access nephroscopy. In one case there was haemorrhage that required treatment by selective embolization. In the rest, RIRS was carried out, all with stones < 30 mm in their greatest diameter without any complications. The mean surgical times were 120 (60-180) minutes for the percutaneous route and of 105 (65-160) minutes for the retrograde route. In all the cases the treatment achieved a complete elimination of the stones or remains of less than 5 mm. CONCLUSIONS: The treatment of renal lithiasis in horseshoe kidneys is complex, given their peculiar anatomy. The usual surgical techniques can be reproduced in these cases with good results. We opt for PCNL in complete staghorn stone and pseudocoraiform stones, whereas RIRS is a valid option in cases with stones < 3 cm.

Experimental infection of horses with Bartonella henselae and Bartonella bovis.

BACKGROUND: Experimental infection of horses with Bartonella species is not documented. OBJECTIVES: Determine clinical signs, hematologic changes, duration of bacteremia, and pattern of seroconversion in Bartonella henselae or Bartonella bovis-inoculated horses. ANIMALS: Twelve (2 groups of 6) randomly selected healthy adult horses seronegative and culture negative for Bartonella spp. METHODS: Experimental/observational study: Group I: B. henselae or saline control was inoculated intradermally into 4 naïve and 2 sentinel horses, respectively. Group II: same design was followed by means of B. bovis. Daily physical examinations, once weekly CBC, immunofluorescent antibody assay serology, real-time polymerase chain reaction (PCR), and twice weekly blood cultures were performed for 6 weeks and at postinoculation day 80 and 139. Bartonella alpha-Proteobacteria growth medium (BAPGM) enrichment blood culture was performed for horses that seroconverted to B. henselae antigens. RESULTS: Transient clinical signs consistent with bartonellosis occurred in some Bartonella-inoculated horses, but hematological alterations did not occur. Three B. henselae-inoculated horses seroconverted, whereas 1 B. bovis-inoculated horse was weakly seropositive. In Group I, B. henselae was amplified and sequenced from BAPGM blood culture as well as a subculture isolate from 1 horse, blood from a 2nd horse, and BAPGM blood culture from a 3rd horse although a subculture isolate was not obtained. All sentinels remained PCR, culture, and serology negative. CONCLUSIONS: Detection of Bartonella sp. in blood after experimental inoculation supports bacteremia and seroconversion. Culture with BAPGM may be required to detect Bartonella sp. Although mild clinical signs followed acute infection, no long-term effects were noted for 2 years postinoculation.

A multicenter retrospective study of 151 renal biopsies in horses.

BACKGROUND: Renal biopsies are uncommonly performed in horses and little is known about their diagnostic utility and associated complication rate. OBJECTIVE: To describe the techniques, the complication rate, risk factors, and histopathology results; as well as evaluate the safety and diagnostic utility of renal biopsy in the horse. ANIMALS: One hundred and forty-six horses from which 151 renal biopsies were obtained. Animals ranged in age from 48 hours to 30 years. METHODS: Multicenter retrospective study, with participation of 14 institutions (1983-2009). RESULTS: Renal biopsy in horses was associated with a similar rate of complications (11.3%) to that occurring in humans and companion animals. Complications were generally associated with hemorrhage or signs of colic, and required treatment in 3% of cases. Fatality rate was low (1/151; 0.7%). Biopsy specimens yielded sufficient tissue for a histopathologic diagnosis in most cases (94%) but diagnoses had only fair (72%) agreement with postmortem findings. Risk factors for complications included biopsy specimens of the left kidney (P = .030), a diagnosis of neoplasia (P = .004), and low urine specific gravity (P = .030). No association with complications was found for age, sex, breed, institution, presenting complaint, other initial clinicopathologic data, biopsy instrument, needle size, or use of ultrasonographic guidance. CONCLUSIONS AND CLINICAL IMPORTANCE: Renal biopsy in horses has low morbidity and results in a morphological histopathologic diagnosis in 94% of cases. However, this procedure might result in serious complications and should only be used when information obtained would be likely to impact decisions regarding patient management and prognosis.