The ability to apply electrosurgical energy via a fluid medium was essential to the development of the functional TURP. The original tungsten wire loop utilized by Stern was coupled to rudimentary spark gap radiofrequency generators developed by Wappler. Davis modified both the design of the loop as well as the generator used to supply the energy (Fig. 5.2). All of these early electrosurgical generators were adaptations of William T. Bovie’s basic design [8]. This was a mono-polar electrosurgical unit, which required the use of a grounding pad. Cutting current incorporates high current and high power in the form of continuous alternating radiofrequency in a sinusoidal wave pattern, which is ideal for cutting tissue but provides minimal coagulation or heating of surrounding tissue. The basic principle is to heat tissue using rapid high temperatures (>100 °C). This results in vaporization of intra and extracellular fluids and hence the smooth cutting of prostatic tissue.

On the other hand, coagulation or fulguration occurs when short bursts of high voltage radiofrequency results in greater depth of penetration of the tissue.

Temperatures generated for coagulation are generally in the 70–100 °C range.

Water was initially used as the irrigation of choice, but water is hypotonic and causes hemolysis and potential electrolyte changes. Water was replaced by fluids of higher osmolality such as glycine or sorbitol, which decreased the deleterious consequences of fluid absorption but did not eliminate the potential for TUR syndrome. TUR syndrome is most often the result of such issues as prolonged resection time, over distention of the bladder and deep resection beyond the capsule of the prostate. High intravesical pressure, from over distension of the bladder has been somewhat mitigated by the introduction of continuous flow resectoscopes. None-the-less TUR syndrome with mono-polar TURP remains a risk in 1–2% of cases.

In the last 50 years many improvements have been made in electrosurgical generators, most notably the advent of solid-state bi-polar systems, which have increased the efficiency of resection while minimizing the risks. There is no longer a need for grounding pads and resections can been done with conductive normal saline irrigation further decreasing the risk of TUR syndrome. These new solid-state generators incorporate a microprocessor feedback system allowing for constant adjustment of power output. Improvement of loop design made bipolar resection possible by allowing return of the current from “smart” generators to occur within the loop itself. The resulting active bipolar electrode produces a localized plasma and actually cuts tissue at a lower thermal temperature and a radio frequency output far less than monopolar generators. The resulting low frequency and low voltage used in bipolar TURP markedly decreases electrical interference with cardiac pacemakers. Depending on the configuration of the electrode, modern bipolar systems can both resect and vaporize prostatic tissue with minimal coagulation artifact.

No other technologic improvement has had a greater impact on the evolution of the TURP than the revolutionary improvements in endoscopic optics , including fiberoptics and video technology, which have largely occurred in the last 30 years.

For the first 30 years of TURP, performance was impeded by poor visualization and poorly illuminated monocular visualization. The original resectoscopes utilized small incandescent light bulbs for illumination. Not only were these small and dim but required frequent replacement. The advent of cold fiberoptic light cables and the elimination of the light bulb illumination was another significant advancement. Although early lenses came in a variety of angles ranging from 0 ° to 120 °, the 15 and 30 ° lenses provided the best field of view for TURP. The early lenses, however, were hampered by poor clarity and narrow angles. The Hopkins rod lens system was a major technological advancement, which replaced the old system of bulky air filled tubes with relay and field lenses with long glass rods which significantly decreased the lens profile while increasing the size and clarity of the image [9] An added benefit of the rod lens system was a ninefold increase in light transmission. This advance greatly helped urologists to better see and more efficiently resect and coagulate prostate tissue. The advent of CCD video camera technology and the use of high definition TV monitors brought urologists out of the dark ages of monocular vision to a more ergonomic and comfortable posture. Not only was binocular visualization achieved, but resectionists no longer needed to contort their bodies, especially their necks, in order to adequately complete their resections.