Tariq A. Khemees

Evaluation of a New 240-μm Single-Use Holmium:YAG Optical Fiber for Flexible Ureteroscopy

BACKGROUND AND PURPOSE Numerous holmium:yttrium-aluminum-garnet laser fibers are available for flexible ureteroscopy. Performance and durability of fibers can vary widely among different manufacturers and their product lines with differences within a single product line have been reported. We sought to evaluate a newly developed nontapered, single-use 240-μm fiber, Flexiva™ 200 (Boston Scientific, Natick, MA), during clinical use and in a bench-testing model. MATERIALS AND METHODS A total of 100 new fibers were tested after their use in 100 consecutive flexible ureteroscopic lithotripsy procedures by a single surgeon (B.K.). Prospectively recorded clinical parameters were laser pulse energy and frequency settings, total energy delivered and fibers failure. Subsequently, each fiber was bench-tested using an established protocol. Parameters evaluated for were fibers true diameter, flexibility, tip degradation, energy transmission in straight and 180° bend configuration and fibers failure threshold with stress testing. RESULTS The mean total energy delivered was 2.20 kJ (range 0-18.24 kJ) and most common laser settings used were 0.8 J at 8 Hz, 0.2 J at 50 Hz, and 1.0 J at 10 Hz, respectively. No fiber fractured during clinical procedures. The true fiber diameter was 450 μm. Fiber tips burnt back an average of 1.664 mm, but were highly variable. With laser setting of 400 mJ at 5 Hz, the mean energy transmitted was 451 and 441 mJ in straight and 180° bend configuration, respectively. Thirteen percent of fibers fractured at the bend radius of 0.5 cm with a positive correlation to the total energy transmitted during clinical use identified. CONCLUSION Fiber performance was consistent in terms of energy transmission and resistance to fracture when activated in bent configuration. Fiber failure during stress testing showed significant correlation with the total energy delivered during the clinical procedure. The lack of fiber fracture during clinical use may reduce the risk of flexible endoscope damage due to fiber failure.

Resilience of disposable endoscope optical fiber properties after repeat sterilization.

OBJECTIVE The PolyScope(®) (Lumenis, Santa Clara, CA) is a disposable flexible ureteroscope composed of a single-use flexible catheter and a reusable fiber optic bundle. We tested the resilience of the optical properties of the reusable optical fiber after repeat sterilization. METHODS Optical properties evaluated were resolution, distortion, and light transmission. Two different optical fibers were tested, one for each sterilization method. Measurements on each fiber were obtained at baseline and were repeated after each set of 10 sterilization cycles for a total of 100 cycles. To measure resolution, the 1951 USAF Contrast Resolution Chart Target was used to subjectively identify the clearest image on the grid by two different operators. To measure distortion, three images of the distortion grid target were captured with a digital camera and analyzed within Image Pro Plus Software. Light transmission was measured using a digital light meter at 50% and 100% transmission. RESULTS There was no significant difference in resolution after 100 sterilization cycles between either Steris or Sterrad NX. Distortion changed by 8.7% and 11.2% for Steris and Sterrad NX, respectively. For Steris at 100% light transmission, baseline was 59 foot-candles and this increased to 85 foot-candles after 100 cycles. For Sterrad NX at 100% light transmission, baseline was 50 foot-candles and this increased to 92 foot-candles after 100 cycles. Results were similar at 50%. There was no significant difference between groups at 50%, 100%, or between sterilization modalities. CONCLUSION The PolyScope fiber optic bundle appears durable after 100 cycles of sterilization with either Steris or Sterrad NX.

Feasibility of Robotic-Assisted Laparoscopic Nephroureterectomy in Left Ventricular Assist Device Patient

Left ventricular assist devices (LVADs) have revolutionized management options for patients with advanced heart failure. It is not uncommon for patients treated with these devices to present with noncardiac surgical conditions including urologic problems. Maintaining perioperative hemodynamic and hematologic stability is a special challenge. The minimally invasive surgery provides well-documented advantages over the open approach including a less operative blood loss and faster convalescence. In carefully selected patients, robotic-assisted surgery can be utilized in the management of patients with complex urologic diseases in a dire need for these benefits. We present the first case of robotic-assisted laparoscopic nephroureterectomy (RANU) with retroperitoneal lymph node dissection for upper tract transitional cell carcinoma (TCC) in a patient treated with LVAD.

Regaining Candidacy for Heart Transplantation after Robotic Assisted Laparoscopic Radical Prostatectomy in Left Ventricular Assist Device Patient

Several factors may highlight the relevance of prostate cancer to the pre-heart-transplant population. First, the expansion in candidate selection criteria led to increased number of men over the age of fifty to be considered for heart transplantation. With the introduction of left ventricular assist device (LVAD) therapy, waiting-list mortality has dramatically declined over the past decade. Additionally, transplant candidates are diligently screened for preexisting neoplasm while on the waiting list. Taken together, screening-detected prostate cancer may increasingly be diagnosed in patients on the waiting list. If discovered, it will pose unique challenge to clinicians as to date there has been no universally accepted management guideline. We report a case of LVAD-treated heart transplant candidate diagnosed with prostate cancer while on the waiting list. Patient screening demonstrated PSA elevation which prompted prostate biopsy. Low-risk clinically localized prostate cancer was confirmed and led to removal of patient from transplant list. When counseled regarding management of his cancer, the patient elected to undergo radical prostatectomy in a hope to regain candidacy for heart transplantation. Despite being of high surgical risk, multidisciplinary team approach led to successful management of prostate cancer and the patient eventually received heart transplant one year following prostatectomy.

Does the Renal Parenchyma Adjacent to the Tumor Contribute to Kidney Function? A Critical Analysis of Glomerular Viability in Partial Nephrectomy Specimens

OBJECTIVE To evaluate the viability of glomeruli in the peritumor parenchyma of partial nephrectomy specimens removed for renal cell carcinoma (RCC) and relate it to kidney function, to better understand the contribution of peritumor parenchyma to renal function. MATERIALS AND METHODS A retrospective analysis of 53 partial nephrectomies containing RCC was performed. Glomeruli within 0.25-cm increments from the tumor were quantified and histologically assessed for viability. Tumor size, minimum and maximum margin size, and pre- and postoperative estimated glomerular filtration rate (eGFR) were obtained. RESULTS Glomerular viability positively correlated with distance from tumor with mean viable glomeruli in successive 0.25-cm increments of 0-0.25 cm, 58%; 0.25-0.5 cm, 80%; 0.5-0.75 cm, 90%; and 0.75-1.0 cm, 92%. Glomerular viability near the tumor did not correlate with preoperative eGFR, whereas decreased viability further from the tumor did correlate with worse preoperative eGFR. Tumor size showed a nonstatistically significant positive trend with minimum (median 0.15 cm) and maximum margin (median 0.7 cm) sizes. Percent change of glomerular filtration rate did not correlate with margin size (P = .190). CONCLUSION Renal parenchyma immediately adjacent to RCC contains fewer viable glomeruli compared with the parenchyma further from the tumor. Based on this information, attempts to preserve all non-neoplastic renal parenchyma via a surgical margin approaching zero may not necessarily result in clinically relevant differences in the amount of viable glomeruli remaining or the renal function preserved.

Fournier’s Gangrene in a Heterosexual Man: A Complication of Neisseria meningitidis Urethritis

A 55-year-old heterosexual male presented to the emergency department with a symptomatology consistent with urethritis and Fourniers gangrene. Urethral swab and operative tissue cultures were positive for coagulase-negative Staphylococcus and an intracellular Gram-negative diplococcus. The latter was initially thought to be Neisseria gonorrhea; however, DNA sequencing technique confirmed it to be Neisseria meningitidis. The patient required three separate surgical debridements to control widespread necrotizing infection. Following documentation of sterile wound healing with appropriate antibiotics, four reconstructive surgeries were necessary to manage the resultant wound defects. To our knowledge, Neisseria meningitidis as a causative organism in Fourniers gangrene has not been reported in the literature.