The relationship between the force applied and perceived by the surgeon during ureteral access sheath placement: ex-vivo experimental model.

PURPOSE: To define a peak force of insertion (PFOI) threshold for ureteral damage during ureteral access sheath (UAS) placement on an experimental ureteral orifice model. METHODS: A specially designed water tank using 2 laparoscopic 5 mm ports and 2 different size (10 Fr and 8 Fr) sealing cap adaptors (SCA) as ureteral orifices was used to perform the test. A 10-12 Fr UAS was fixed to a load cell and the force of insertion (FOI) was continuously recorded with a digital force gauge.13 experts in the field of endourology who participated performed 3 UAS insertions. The FOI was recorded initially with 10 Fr followed by 8 Fr SCA. On the final insertion, the orifice was obstructed, leaving a 5 cm length to insert the UAS. The experts were asked to "Stop at the point they anticipate ureteral damage, and they would not proceed in real life". RESULTS: Using 10 Fr SCA the PFOI was 2.12 ± 0.58 Newton (N) (range:1.48-3.48) while 8 Fr SCA showed a PFOI 5.76 ± 0.96 N (range:4.05-7.35). Six of the experts, said they would stop proceeding when they reached above 5.1 N. Three experts had PFOI < 5.1 N and the other 4 stated they would go with PFOIs of 5.88, 6.16, 6.69 and 7.35 N when using SCA of 8 Fr.The highest load they would stop proceeding had a PFOI of 6.09 ± 1.87 N (range: 2.53-10.74). CONCLUSION: The PFOI threshold for ureteral damage inserting UAS of the experts is variable. Although FOI is a subjective perception, experience suggests that ureteral injury may occur at an average of 6.05 N perceived by surgeons' tactile feedback. In-vivo measurement of UAS PFOI may confirm a threshold.

Urolithiasis associated with topiramate

OBJECTIVE: Topiramate is a sulfamate-substituted monosaccharide anticonvulsant used as adjunctive therapy for intractable refractory seizures. It is report a case of topiramate-induced urolithiasis. CASE REPORT: A 35-year-old man presented with acute, right-sided, colicky flank pain. He denied hematuria or dysuria. He was in use of phenytoin, risperidone, phenobarbital, and topiramate. The total daily dose of topiramate was 375 mg. A CT scan showed a 7 x 1 mm curvilinear density at the right ureterovesical junction with proximal hydrouretronephrosis. He was managed with rigid ureteroscopic stone extraction and the calculus metabolic analysis revealed the stone was composed of carbonate apatite (70 percent), calcium oxalate dihydrate (20 percent), and calcium oxalate monohydrate (10 percent). COMMENTS: The present case typifies many features of topiramate-induced urolithiasis. Those who care for patients with urinary stone disease should be aware of this association.

Tratamiento de la nefrolitiasis y la ureterolitiasis / Nephrolithiasis and ureteroliasis treatment

El desarrollo tecnológico esta revolucionando el tratamiento de la litiasis urinaria mediante la introducción de métodos no quirúrgicos e incluso no invasores que garantizan elevadas tasas de curación con minimas complicaciones y enorme reducción de la incapacidad posterior al tratamiento. Una vez eliminados los cálculos, el tratamiento médico puede ayudar a prevenir las recidivas con base en un adecuado estudio de los factores de riesgo y su modificación mediante diversas modalidades terapéuticas que permitan corregir las alteraciones fisicoquímicas responsables de la formación de cálculos urinarios.