Fragmentation of Stones by Burst Wave Lithotripsy in the First 19 Humans

PURPOSE

We report stone comminution in the first 19 human subjects by burst wave lithotripsy (BWL), which is the transcutaneous application of focused, cyclic ultrasound pulses.

MATERIALS AND METHODS

This was a prospective multi-institutional feasibility study recruiting subjects undergoing clinical ureteroscopy (URS) for at least 1 stone ≤12 mm as measured on computerized tomography. During the planned URS, either before or after ureteroscope insertion, BWL was administered with a handheld transducer, and any stone fragmentation and tissue injury were observed. Up to 3 stones per subject were targeted, each for a maximum of 10 minutes. The primary effectiveness outcome was the volume percent comminution of the stone into fragments ≤2 mm. The primary safety outcome was the independent, blinded visual scoring of tissue injury from the URS video.

RESULTS

Overall, median stone comminution was 90% (IQR 20, 100) of stone volume with 21 of 23 (91%) stones fragmented. Complete fragmentation (all fragments ≤2 mm) within 10 minutes of BWL occurred in 9 of 23 stones (39%). Of the 6 least comminuted stones, likely causative factors for decreased effectiveness included stones that were larger than the BWL beamwidth, smaller than the BWL wavelength or the introduction of air bubbles from the ureteroscope. Mild reddening of the papilla and hematuria emanating from the papilla were observed ureteroscopically.

CONCLUSIONS

The first study of BWL in human subjects resulted in a median of 90% comminution of the total stone volume into fragments ≤2 mm within 10 minutes of BWL exposure with only mild tissue injury.

Schwannomas of the sinonasal tract and anterior skull base: a systematic review of 94 cases

BACKGROUND

Schwannomas of the anterior skull base (ASB) and sinonasal tract are extremely rare. These lesions mimic other pathologies such as olfactory groove meningiomas, hemangiopericytomas, and esthesioneuroblastomas. Because of their low incidence, ASB and sinonasal tract schwannomas have not been well characterized. A systematic review of ASB and sinonasal tract schwannomas was conducted to further elucidate the presentation and surgical management of these lesions.

METHODS

A MEDLINE/PubMed search was performed, identifying 71 articles representing 94 cases of ASB and sinonasal schwannomas. Each case was analyzed for demographics, clinical presentation, anatomic location, radiographic features, and surgical treatment.

RESULTS

In 94 patients with ASB and sinonasal schwannomas, 44 (46.8%) were exclusively sinonasal, 30 cases (31.9%) were exclusively intracranial, 12 (12.8%) were primarily intracranial with extension into the paranasal sinuses, and 8 (8.5%) were primarily sinonasal with intracranial extension. Headaches and nasal obstruction were the most common presenting symptoms occurring in 30.9 and 29.8% of cases, respectively. Magnetic resonance imaging typically showed a hyperintense mass on T2-weighted imaging (70%) and hypointense (41%) on T1-weighted imaging. Most patients underwent surgical gross total resection via craniotomy, endoscopic endonasal approach, rhinotomy, or other sinonasal approaches. Recurrence occurred in three cases ranging from 4 months to 13 years. Postoperative complications included cerebral spinal fluid leakage, bacterial meningitis, epidural hematoma, and pneumocranium.

CONCLUSION

ASB and sinonasal schwannomas are rare lesions and should be considered in the differential diagnosis of ASB masses involving the cribriform plate with sinonasal extension. Gross total resection of these lesions should be considered the goal of operative management.

Expert witness testimony in urology malpractice litigation

OBJECTIVE

To evaluate the credentials of urologists choosing to testify as expert witnesses. As health care reform has become an increasingly important topic in national debate, medical malpractice and related issues have come to the forefront of topics for discussion by the medical community. Physicians are often recruited to testify as expert witnesses in malpractice cases. Defining what constitutes an expert in this setting has been an area of controversy.

METHODS

The Westlaw legal database was searched for medical malpractice litigation. Data regarding number of years of experience and practice setting were obtained for urologists using private practice and hospital listings, academic faculty profiles, and state medical licensing databases. Scholarly impact, as measured by the h-index, was calculated by the Scopus database.

RESULTS

Plaintiff expert witnesses were found to have slightly more years of experience vs defendant expert witnesses (35.7 vs 32.2 years, P = .01), but had a lower h-index (6.8 vs 10.2, P = .03), were less likely to practice in the academic setting (39% vs 60%, P = .001), and were more likely to testify multiple times.

CONCLUSION

Urologists testifying for plaintiffs and defendants both had over 30 years of experience on average, with those in the latter having slightly less experience. Defendant witnesses, however, had greater scholarly impact and were more likely to practice in an academic setting. Organizations such as the American Urological Association may wish to re-evaluate guidelines on expert witness testimony, particularly regarding those who testify frequently.

Vesico-ureteric reflux (VUR) management and screening patterns: are paediatric urologists following the 2010 American Urological Association (AUA) guidelines?

OBJECTIVE

To evaluate the current practice patterns of vesico-ureteric reflux (VUR) management and screening among paediatric urologists and their relationship with the current American Urological Association (AUA) guidelines in managing and treating VUR.

SUBJECTS AND METHODS

A 17-question survey was sent out to 476 paediatric urologists who are members of the Society for Pediatric Urology (SPU). In all, 133 respondents answered the survey and results were included for all questions.

RESULTS

Paediatric urologists who were surveyed were consistent with the 2010 AUA guidelines in the initial evaluation of children with VUR, continuous antibiotic prophylaxis for the child aged < or >1 year, and follow-up evaluation in children with VUR. Most paediatric urologists do not obtain a serum creatinine on initial screening of children with VUR. The new guidelines address screening of siblings of patients with VUR and most paediatric urologists were consistent with these recommendations. Almost one third of responders screened all neonates diagnosed with prenatal hydronephrosis regardless of clinical history or findings on imaging despite the recommendations of the new guidelines.

CONCLUSION

We conclude that based on our present sample, most paediatric urologists follow the 2010 AUA guidelines on VUR management.