Dylan Isaacson

A Prospective Case–Control Study Comparing LithoVue, a Single-Use, Flexible Disposable Ureteroscope, with Flexible, Reusable Fiber-Optic Ureteroscopes

OBJECTIVE LithoVue™ is a novel, single-use, digital flexible ureteroscope that was released to the US market in January 2016. There are scant data regarding its performance in humans. Procedural outcomes comparing LithoVue with reusable ureteroscopes are presented in patients undergoing ureteroscopy for upper urinary tract pathology. PATIENTS AND METHODS Clinical outcomes between two groups of patients undergoing flexible ureteroscopy for upper urinary tract pathology were analyzed. The first group underwent surgery utilizing LithoVue, and the second group used reusable fiber-optic flexible ureteroscopes. Differences in procedural outcomes, operative times, and time spent in hospital were analyzed using two-tailed t-tests and chi-squared and Fishers exact tests. RESULTS One hundred fifteen cases utilizing LithoVue and 65 cases utilizing reusable ureteroscopes were included in this study. Demographics, surgical indications, stone size, location, total stone burden, composition, procedural outcomes, and complications were comparable between groups. For all cases, LithoVue procedures lasted 54.1 ± 25.7 minutes compared with 64.5 ± 37.0 minutes for reusable scope procedures (p < 0.05) and for stone removal cases, 57.3 ± 25.1 vs 70.3 ± 36.9 minutes, respectively (p < 0.05). Scope failure occurred in 4.4% of LithoVue cases and 7.7% of reusable cases (p = 0.27). CONCLUSIONS LithoVue represents a feasible alternative to reusable ureteroscopes with a low rate of scope failure comparable with reusable ureteroscopes. Its use shortens procedure duration, a finding that warrants further investigation.

Macroscopic Whole-Mounts of the Developing Human Fetal Urogenital-Genital Tract: Indifferent Stage to Male and Female Differentiation

We present a detailed review of fetal development of the male and female human urogenital tract from 8 to 22 weeks gestation at the macroscopic and morphometric levels. Human fetal specimens were sexed based on macroscopic identification of fetal testes or ovaries, Wolffian or Müllerian structures and the presence of the SRY gene in the specimens at or near the indifferent stage (8-9 weeks). Specimens were photographed using a dissecting microscope with transmitted and reflected light. Morphometric measurements were taken of each urogenital organ. During this time period, development of the male and female urogenital tracts proceeded from the indifferent stage to differentiated organs. The kidneys, ureters, and bladder developed identically, irrespective of sex with the same physical dimensions and morphologic appearance. The penis, prostate and testis developed in males and the clitoris, uterus and ovary in females. Androgen-dependent growth certainly influenced size and morphology of the penile urethra and prostate, however, androgen-independent growth also accounted for substantial growth in the fetal urogenital tract including the clitoris.

Development of the human penis and clitoris

The human penis and clitoris develop from the ambisexual genital tubercle. To compare and contrast the development of human penis and clitoris, we used macroscopic photography, optical projection tomography, light sheet microscopy, scanning electron microscopy, histology and immunohistochemistry. The human genital tubercle differentiates into a penis under the influence of androgens forming a tubular urethra that develops by canalization of the urethral plate to form a wide diamond-shaped urethral groove (opening zipper) whose edges (urethral folds) fuse in the midline (closing zipper). In contrast, in females, without the influence of androgens, the vestibular plate (homologue of the urethral plate) undergoes canalization to form a wide vestibular groove whose edges (vestibular folds) remain unfused, ultimately forming the labia minora defining the vaginal vestibule. The neurovascular anatomy is similar in both the developing human penis and clitoris and is the key to successful surgical reconstructions.

Development of the human female reproductive tract

Development of the human female reproductive tract is reviewed from the ambisexual stage to advanced development of the uterine tube, uterine corpus, uterine cervix and vagina at 22 weeks. Historically this topic has been under-represented in the literature, and for the most part is based upon hematoxylin and eosin stained sections. Recent immunohistochemical studies for PAX2 (reactive with Müllerian epithelium) and FOXA1 (reactive with urogenital sinus epithelium and its known pelvic derivatives) shed light on an age-old debate on the derivation of vaginal epithelium supporting the idea that human vaginal epithelium derives solely from urogenital sinus epithelium. Aside for the vagina, most of the female reproductive tract is derived from the Müllerian ducts, which fuse in the midline to form the uterovaginal canal, the precursor of uterine corpus and uterine cervix an important player in vaginal development as well. Epithelial and mesenchymal differentiation markers are described during human female reproductive tract development (keratins, homeobox proteins (HOXA11 and ISL1), steroid receptors (estrogen receptor alpha and progesterone receptor), transcription factors and signaling molecules (TP63 and RUNX1), which are expressed in a temporally and spatially dynamic fashion. The utility of xenografts and epithelial-mesenchymal tissue recombination studies are reviewed.

Immunohistochemical expression analysis of the human fetal lower urogenital tract

We have studied the ontogeny of the developing human male and female urogenital tracts from 9 weeks (indifferent stage) to 16 weeks (advanced sex differentiation) of gestation by immunohistochemistry on mid-sagittal sections. Sixteen human fetal pelvises were serial sectioned in the sagittal plane and stained with antibodies to epithelial, muscle, nerve, proliferation and hormone receptor markers. Key findings are: (1) The corpus cavernosum in males and females extends into the glans penis and clitoris, respectively, during the ambisexual stage (9 weeks) and thus appears to be an androgen-independent event. (2) The entire human male (and female) urethra is endodermal in origin based on the presence of FOXA1, KRT 7, uroplakin, and the absence of KRT10 staining. The endoderm of the urethra interfaces with ectodermal epidermis at the site of the urethral meatus. (3) The surface epithelium of the verumontanum is endodermal in origin (FOXA1-positive) with a possible contribution of Pax2-positive epithelial cells implying additional input from the Wolffian duct epithelium. (4) Prostatic ducts arise from the endodermal (FOXA1-positive) urogenital sinus epithelium near the verumontanum. (5) Immunohistochemical staining of mid-sagittal and para-sagittal sections revealed the external anal sphincter, levator ani, bulbospongiosus muscle and the anatomic relationships between these developing skeletal muscles and organs of the male and female reproductive tracts. Future studies of normal human developmental anatomy will lay the foundation for understanding congenital anomalies of the lower urogenital tract.

Renal Subcapsular xenografing of human fetal external genital tissue – A new model for investigating urethral development

In this paper, we introduce our novel renal subcapsular xenograft model for the study of human penile urethral and clitoral development. We grafted fifteen intact fetal penes and clitorides 8-11 weeks fetal age under the renal capsules of gonadectomized athymic mice. The mice were treated with a subcutaneous pellet of dihydrotestosterone (DHT), diethylstilbestrol (DES) or untreated with hormones. Xenografts were harvested after fourteen days of growth and analyzed via serial histologic sectioning and immunostaining for Ki-67, cytokeratins 6, 7 and 10, uroplakin and the androgen receptor. Non-grafted specimens of similar fetal age were sectioned and immunostained for the same antigenic markers. 14/15 (93.3%) grafts were successfully propagated and harvested. The developing urethral plate, urethral groove, tubular urethra, corporal bodies and preputial lamina were easily identifiable. These structures demonstrated robust cellularity, appropriate architecture and abundant Ki-67 expression. Expression patterns of cytokeratins 6, 7 and 10, uroplakin and the androgen receptor in xenografted specimens demonstrated characteristic male/female differences analogous to non-grafted specimens. DHT treatment reliably produced tubularization of nascent urethral and vestibular structures and male patterns of androgen receptor expression in grafts of both genetic sexes while estrogenic or hormonally absent conditions reliably resulted in a persistent open urethral/vestibular groove and female patterns of androgen receptor expression. This models success enables further study into causal pathways by which endocrine-disrupting and endocrine-mimicking substances may directly cause disruption of normal human urethral development or hypospadias.

Novel handwashes are superior to soap and water in removal of Clostridium difficile spores from the hands

We examined the efficacy of 5 experimental handwash formulations in removing nontoxigenic Clostridium difficile spores from the hands of health care workers. Handwashing with sand resulted in an additional 0.5-log reduction in spore recovery compared with the current standard of soap and water.

The galliform (Turkey thigh) model for resident training in facial plastic surgery

INTRODUCTION Learning the subtleties of dissection and tissue rearrangement requires study and practice. Students with prior exposure to soft tissue techniques are most likely to benefit from teaching in the operating room. Soft tissue simulation allows necessary repetition and facilitates understanding of complex flap procedures. It also permits objective assessment of skill level. Educators have employed numerous materials and models to facilitate acquisition of cutaneous surgical skills. These include pigs’ feet, synthetic multilayered skin pads, stretched animal skins, human cadavers, live mice, and virtual reality simulators. Each has its limitations. Pigs’ feet are widely used in surgical training as a model for human skin. Although structurally similar to the skin of human extremities, pig skin is thick and inflexible, making it a poor stand-in for human facial tissues. Multilayer commercial synthetic models simulate epidermal, dermal, and fat layers. They allow for undermining and subcuticular closure techniques and carry no risk of infection or contamination. However, these models are expensive, and plastic layers imitate the feel of tissue poorly. Stretched animal skins require considerable setup time and lack deep tissue layers. Live animals play an important role in the development of microvascular technique, but are expensive and ethically questionable when nonviable alternatives are available. Formalin-fixed cadavers have rigid soft tissues that do not handle well. Fresh human parts are technically ideal but are rare, expensive, and pose a significant infection risk. Computer-based virtual reality simulators featuring tissue deformation and haptic feedback are not yet fully developed. We present a facial soft tissue surgery model using defeathered fresh turkey thighs. It is inexpensive, readily available, and carries a low risk of zoonotic infection. We describe the histologic structure of galliform skin and compare its operative handling characteristics to human tissue and the more commonly used porcine limb model.

Micro-costing analysis demonstrates comparable costs for LithoVue™ compared to reusable flexible fiberoptic ureteroscopes

INTRODUCTION Reusable ureteroscope durability and need for repair are significant sources of expense and inefficiency for patients and urologists. Utilization of LithoVue™, a disposable flexible digital ureteroscope, may address some of these concerns. To identify its economic impact on clinical care, we performed a micro-cost comparison between flexible reusable fiberoptic ureteroscopes (URF-P6™) and LithoVue. PATIENTS AND METHODS For this prospective, single-center micro-costing study, all consecutive ureteroscopies performed during 1 week each in July and August 2016 utilized either URF-P6 or LithoVue ureteroscopes respectively. Workflow data were collected, including intraoperative events, postoperative reprocessing cycle timing, consumables usage, and ureteroscope cost data. RESULTS Intraoperative data analysis showed mean total operating room time for URF-P6 and LithoVue cases were 93.4 ± 32.3 and 73.6 ± 17.4 minutes, respectively (p = 0.093). Mean cost of operating room usage per case was calculated at

Development of the human prostate.

1618.72 ± 441.39 for URF-P6 and