These prevent migration downwards (out of the ureter) or upwards (into the ureter). They ar e, therefore, \200\230self-retaining \200\231. Made of polymers of variable strength and b iodurability. Some stents have a hydrophilic coating which absorbs water and thereby, makes them more slippery and easier to insert. Stents are impregnated with barium- or bismuth-co ntaining metallic salts to make them radio-opaque so that they can be visualized radio- gra phically to ensure correct positioning. Types Classi \201 ed by size and length. Common sizes are 6 or 7 Ch (Fig. 17.10). Common l engths for adults are 22 \200\22328cm. Multilength stents are of vari- able length, allowin g them to accommodate to ureters of different length. A new stent design, the PolarisTM loo p (Boston Scienti \201 c), is said to reduce bladder irritation and to make removal easier . Stent materials Polyurethane; silicone; C- \202 ex; Silitek; Percu \202 ex; biodegradable (experi- mental \200\224obviates the need for stent removal and eliminates the possibil- i ty of the \200\230forgotten stent \200\231). Some are coated (by chemical bonding) with a hydrogel (e.g. HydroPlusTM) which provides a low friction surface so making insertion easie r, encrustation less likely, and in theory, makes the stent more comfortable (whether this is the case in practice has not been established). Indications and uses \200 Relief of obstruction: from ureteric stones; benign (i.e. ischaemic) ureteric strictures; m alignant ureteric strictures. The stent will relieve the pain caused by obstruction and rev erse renal impairment if present. Prevention of obstruction: post-ureteroscopy (routine ste nting after \200\230uncomplicated \200\231* ureteroscopy is not necessary). Indications fo r J stenting post-ureteroscopy: \200 \200 \200 \200 \200 Prevention of obstructio n post-ESWL. Indications for J stenting post-ESWL:1 \200 Ureteric injury. Solitary kidney. Large residual stone burden. Raised creatinine (implying overall impaired renal function). Ureteric stricture. \200 Stents reduce the incidence of steinstrasse with large renal calculi (1.5 \200\2233.5cm, 6% with a stent, and 13% without develop a steinstrasse post-ESWL). Solitary kidney. JJ STENTS 725 Fig. 17.10 A JJ stent. \200 Raised creatinine (implying overall impaired renal function). (The analysis by the Joint AU A/EAU Nephrolithiasis Guideline Panel 20072 found no improvement in stone fragmentation wit h stenting, i.e. stents do not enhance ESWL ef \201 cacy.) \200 \200\230Passive \200\231 dilatation of ureter prior to ureteroscopy. To ensure antegrade \202 ow of urine following surgery (e.g. pyeloplasty) or injury to ureter. Following endop yelotomy (endopyelotomy stents have a tapered end, from 14 to 7 Ch, to keep the incised ure ter \200\230open \200\231). Post-renal transplantation (stenting of re-implanted ureter). An alternative to the J stent A short-term 4 or 6 Ch ureteric catheter, attached to a 12 Ch urethral catheter (to stop the ureteric catheter from falling out), is an alternative form of post-ureteroscopy drainage. In an RCT of 24h of ureteric catheter drainage post-ureteroscopy com- pared with no drainag e, the non-catheterized group were more likely to report renal colic (45% vs 2%) and to hav e loin pain (76% vs 20%) than the ureteric catheterized group.3 Analgesic use was greater i n the non- catheterized group (67% vs 20%). Twenty percent of non-catheterized patients and 5% of catheterized returned to hospital for analgesia (but no patient required readmission ). The only disadvantage of this technique was a higher reported rate of urethral irritatio n (37% vs 4%) in the catheterized patients. It has the obvious advantage of ease of removal of the catheter The de \201 nition of \200\231uncomplicated \200\231 ureteroscopy is not precise. \200 \230Complicated \200\231 ureteroscopy has been variously de \201 ned as (a) ureteral perfo ration (i.e. mucosal injury); (b) severe ureteric oedema at the site of the stone; (c) impa ction (which means dif \201 culty getting a guidewire past the stone ( \200\230cork in a b ottle \200\231 stone); (d) prolonged operation (no precise de \201 nition of what \200 \230long \200\231 is); (e) one where ureteral dilatation was carried (to de \201 ne such u reteroscopies as \200\230complicated \200\231 is contentious because some urologists routi nely \200\230dilate \200\231 with a dual lumen catheter to allow double guidewire placemen t. Does this automatically make all their ureteroscopies \200\230complicated \200\231?). CHAPTER 17 Urological surgery and equipment 726 without the need for a second procedure and avoids the potential risk of the forgotten sten t. Symptoms and complications of stents \200 Stent symptoms: common (78%) \200\224suprapubic pain, LUTS (frequency, urgency \200\224sten t irritates trigone), haematuria, inability to work.4 More than 80% of patients have stent- related pain that affects daily activities, 32% report sexual dysfunction, and 58% report r educed work capacity and loss of income. A-blockers may help reduce pain with voiding and o verall analgesic use. development of bacteriuria after stenting is common. In a small UTI: proportion, sepsis can develop. In such cases, consider placement of a urethral catheter to lower the pressure in the collecting system and prevent re \202 ux of infected urine. Ste nts coated with the antibacterial triclosan are no better than non-coated stents in prevent ing stent- associated UTI. Incorrect placement: subsequent stent removal requires ureterosc opy; can be technically dif \201 cult; percutaneous removal may be required). Too low (pro ximal end not in renal pelvis; stent may not, therefore, relieve obstruction). (up the uret er or down the ureter and into bladder). Stent migration Stent blockage: catheters and sten ts become coated with a bio \201 lm when in contact with urine (a protein matrix secreted by bacteria- colonizing stent). Calcium, magnesium, and phosphate salts become deposited. B io \201 lm build-up can lead to stent blockage or stone formation on the stent (Fig. 17.11 ). Stents coated with heparin are no better than non-coated stents in preventing stent bio \201 lm formation or encrustation. The \200\230forgotten stent \200\231: may become encru sted with stone, making removal technically very dif \201 cult. If the proximal end only i s encrusted, PCNL may be required to remove the stone and then the stent. If the entire ste nt is encrusted, open removal via several incisions in the ureter may be necessary. too high (distal end of stent in ureter; \200 rare, but potentially very serious as the bio \201 lm JJ STENTS 727 Fig. 17.11 An encrusted stent. Commonly asked questions about stents Does urine pass though the center of the stent? No, i t passes around the outside of the stent. Re \202 ux of urine occurs through the center. Should I place a JJ stent after ureteroscopy? (see Indications and uses) A stent should be placed if: \200 There has been ureteric injury (e.g. perforation \200\224indicated by extravasation of cont rast). There are residual stones that might obstruct the ureter. The patient has had a uret eric stricture that required dilatation. Solitary kidney. Raised creatinine (implying overa ll impaired renal function). \200 \200 \200 Routine stenting after ureteroscopy for distal ureteric calculi is unneces- sary.5,6 Many u rologists will place a stent after ureteroscopy for proximal ureteric stones. Do stents cause obstruction? In normal kidneys, stents cause a signi \201 cant and substan tial increase in intrarenal pressure, which persists for up to 3 weeks.7 (This can be pre- vented by placing a urethral catheter.) CHAPTER 17 Urological surgery and equipment 728 Do stents aid stone passage? Ureteric peristalsis requires coaptation of the wall of the ur eter proxi- mal to the bolus of urine to be transmitted down the length of the ureter. JJ s tents paralyze ureteric peristalsis. In dogs, the amplitude of each peristaltic wave (measu red by an intraluminal ureteric balloon) falls (from 50 to 15mmHg) and the frequency of ure teric peristalsis falls (from 11 to 3 waves/min). Peristalsis takes several weeks to recove r. 3mm ball bearings placed within a non-stented dog ureter take 7 days to pass compared wi th 24 days in a stented ureter. Are stents able to relieve obstruction due to extrinsic compression of a ureter? Stents are less effective at relieving obstruction due to extrinsic obstruc- tion by, for example, tu mor or retroperitoneal obstruction.8 They are much more effective for relieving obstruction by an intrinsic problem (e.g. a stone). Placement of two stents may provide more effective drainage ( \201 gure-of-eight con \201 guration may produce more space around the stents for drainage). For acute, ureteric stone obstruction with a fever, should I place a JJ stent or a nephrost omy? In theory, one might imagine that a nephrostomy is better than a JJ stent \200\224it c an be done under local anesthetic (JJ stent insertion may require general anesthesia); it l owers the pressure in the renal pelvis to 0 or a negative value whereas a JJ stent results in a persistently positive pressure, it is less likely to be blocked by thick pus, and it a llows easier subsequent imaging (contrast can be injected down the ureter \200\224a neph- r ostogram \200\224to determine if the stone has passed). A randomized trial of 42 patients w ith obstructing, infected stones (temperature >38 C and/ or WBC >17 000/mm3) showed J sten ting (6 or 7 Ch J stent with a Foley bladder catheter) and nephrostomy drainage (8 Ch) to b e equally effec- tive in terms of time to normalization of temperature and white count (app roximately 2 \200\2233 days) and in-hospital stay. As a consequence, the EAU/ AUA Nephrolit hiasis Guideline Panel10 recommends that the system of drainage of the obstructed, infected kidney is left to the discretion of the urologist. JJ STENTS 729 1 Al-Awadi KA, Abdul Halim H, Kehinde EO, Al-Tawheed A (1999) Steinstrasse: a comparison of incidence with and without J stenting and the effect of J stenting on subsequent managemen t. BJU Int 84:618 \200\22321. 2 Preminger GM, Tiselius HG, Assimos DG, et al. (2007) 2007 Guideline for the management of ureteral calculi, joint EAU/AUA Nephrolithiasis Guideline Panel. J Urol 178:2418 \200\2233 4. 3 Djaladat H, Tajik P, Payandemehr P, Alehashemi S (2007) Ureteral catheterization in uncom pli- cated ureterolithotripsy: a randomized, controlled trial. Eur Urol 52:836 \200\22341. 4 symptoms, quality of life and utility. J Urol 169:1065 \200\2239. Joshi HB, Stainthorpe A, MacDonagh RP, et al. (2003) Indwelling ureteral stents: evaluation of 5 Srivastava A, Gupta R, Kumar A, Kapoor R, Mandhani A (2003) Routine stenting after ureter os- copy for distal ureteral calculi is unnecessary: results of a randomized controlled tri al. J Endourol 17:871 \200\2234. 6 Netto Jr NR, Ikonomidis J, Zillo C (2001) Routine ureteral stenting after ureteroscopy fo r ure- teral lithiasis: is it really necessary? J Urol 166:1252 \200\2234. 7 Ramsay JW, Payne SR, Gosling PT, Whit \201 eld HN, Wickham JE, Levison DA (1985) The eff ects of double J stenting on obstructed ureters. An experimental and clinical study. Br J U rol 57:630 \200\2234. 8 Docimo SG (1989) High failure rate of indwelling ureteral stents in patients with extrins ic obstruction: experience at two institutions. J Urol 142:277 \200\2239. 9 Pearle MS, Pierce HL, Miller GL, et al (1998) Optimal method of urgent decompression of t he collecting system for obstruction and infection due to ureteral calculi. J Urol 160:1260 \200\2234. 10 Preminger GM, Tiselius HG, Assimos DG, et al. (2007) 2007 Guideline for the management o f ureteral calculi Joint EAU/AUA Nephrolithiasis Guideline Panel. J Urol 178:2418 \200\2233 4. CHAPTER 17 Urological surgery and equipment 730 Lasers in urological surgery Light ampli \201 cation by stimulated emission of radiation. Photons are emitted when an atom is stimulated by an external energy source and its electro ns, having been so excited, revert to their steady state. In a laser, the light is coherent (all the photons are in phase with one another), collimated (the photons travel parallel t o each other), and of the same wavelength (monochromatic). The light energy is thus \200 \230concen- trated \200\231, allowing delivery of high energy at a desired target. The holmium:YAG laser is currently the principal urological laser. It has a wavelength of 2 140nm and is highly absorbed by water and, therefore, by tissues which are composed mainly of water. The majority of the holmium laser energy is absorbed super \201 cially, resultin g in a super \201 cial cutting or ablation effect. The depth of the thermal effect is no g reater than 1mm. The holmium:YAG laser produces a cavitation bubble that generates only a w eak shock wave as it expands and collapses. Holmium laser lithotripsy occurs primarily thro ugh a photothermal mechanism that causes stone vaporization. Uses of the holmium:YAG laser \200 Laser lithotripsy (ureteric stones, small intrarenal stones, bladder stones). Resection of the prostate (holmium laser prostatectomy). Division of urethral strictures. Division of ur eteric strictures, including PUJO. Ablation of small bladder, ureteric, and intrarenal TCCs . \200 \200 \200 Advantages \200 The holmium laser energy is delivered via a laser \201 bre (Fig. 17.12) which is thin eno ugh to allow its use down a \202 exible instrument without affecting the de \202 ection of that instrument and can, therefore, gain access to otherwise inaccessible parts of the k idney. Zone of thermal injury adjacent to the tip of the laser \201 bre is limited to no more than 1mm; the laser can safely be \201 red at a distance of 1mm from the wall of the ureter. Can be used for all stone types. Minimal stone migration effect because of minimal shock wave generation. \200 Disadvantages \200 \200 High cost. Produces a dust cloud during stone fragmentation, which temporarily obscures the view. Can irreparably damage endoscopes if inadvertently \201 red near or within the sco pe. Relatively slow stone fragmentation \200\224the laser \201 bre must be \200\230paint ed \200\231 over the surface of the stone to vaporize it. LASERS IN UROLOGICAL SURGERY 731 Greenlight PVP for TURP The 80 or 120W KTP laser is used for photoselective vaporization of the prostate. The laser is green (hence, the name \200\230greenlight \200\231 laser) and is absorbed by hemoglobin, generating a heating effect which causes vapori- zation of targe ted tissue. The procedure is done under general or spinal anesthetic. Advantages Saline is used for irrigation (therefore, no risk of TUR syndrome). Disadvantages No tissue for histological examination. Fig. 17.12 Holmium laser \201 bre. CHAPTER 17 Urological surgery and equipment 732 Diathermy Diathermy is the coagulation or cutting of tissues through heat. Monopolar diathermy When an electric current passes between two contacts on the body, there is an increase in temperature in the tissues through which the cur- rent \202 ows. This increase in temperature depends on the volume of tissue through which the current passes, t he resistance of the tissues, and the strength of the current. The stronger the current, th e greater the rise in temperature. If one contact is made large, the heat is dissipated ove r a wide area and the rise of temperature is insigni \201 cant. This is the earth or neutr al electrode and under this, the rise in temperature is only 1 or 2 C. The working electro de or diathermy loop is thin so that the current density is maximal and, therefore, so is t he heating effect. When a direct current is switched on or off, nerves are stimulated and muscles will twitch. If the switching on and off is rapid enough, there is the sustained contraction familiar t o the physiology class as the \200\230tetanic contraction \200\231. If a high frequency al ternating current is used (300kHz to 5MHz), there is no time for the cell membranes of nerv e or muscle to become depolarized and nerves and muscles are not stimulated (they are stimu lated at lower frequencies). The effect of the diathermy current on the tissues depends on the heat that is generated un der the diathermy loop. At relatively low temper- atures, coagulation and distortion of sma ll blood vessels occurs. If the current is increased to raise the temperature further, wate r within cells vaporizes and the cells explode. This explosive vaporization literally cuts the tissues apart. Bipolar diathermy Bipolar diathermy involves the passage of electrical current between two electrodes on the same hand piece. It is inherently safer than monopolar diathermy since th e current does not pass through the patient and dia- thermy burns cannot, therefore, occur. Potential problems with diathermy The diathermy isn \200\231t working \200 \200 Do not increase the current. Check that the irrigating \202 uid is glycine (sodium chlori de conducts electricity causing the diathermy to short-circuit). Check that the diathermy p late is making good contact with the skin of the patient. Check that the lead is undamaged. Check that the resectoscope loop is securely \201 xed to the contact. \200 Modern diathermy machines have warning circuits which sound an alarm when there is imperfec t contact between the earth plate and the patient. DIATHERMY 733 Diathermy burns If current returns to earth through a small contact rather than the broad a rea of the earth pad, then the tissues through which the current passes will be heated just like those under the cutting loop. If the pad is making good contact, the current will \201 nd it easier to run to earth through the pad and no harm will arise, even when there i s accidental contact with some metal object. The real danger arises when the diathermy pad is not making good contact with the patient. It may not be plugged in or its wire may be br oken. Under these circumstances, the current must \201 nd its way to earth somehow and an y contact may then become the site of a dangerous rise in temperature. Pacemakers and implantable cardioverter de \201 brillators (ICDs) and the use of diathermy See Box 17.2 for diathermy problems and their prevention. CHAPTER 17 Urological surgery and equipment 734 Box 17.2 Pacemakers, ICDs, and diathermy: problems and their prevention Diathermy can cause electrical interference of a pacemaker or ICD, leading to inhibition, triggering of electr ical output from the device, reprogramming, asynchronous pacing, damage to the circuitry of the device, or triggering of de \201 brillator discharge. An electrical current can also be induced in the pacemaker or ICD leads, which can, in turn, cause tissue heating, leading to myocardial damage. \200 Pacemaker inhibition: may simulate the electrical activity of myocardial contraction so the pacemaker can be inhibited. If the patient is pacemaker-dependent, the heart may stop. Pha ntom reprogramming: the radiofrequency impulse by which the pacemaker can be reprogrammed t o different settings. The pacemaker may then start to function in an entirely different mod e. \200 the high frequency of diathermy current the diathermy current may also simulate The internal mechanism of the pacemaker: may be damaged by the diathermy current if this is applied close to the pacemaker. Ventricular \201 brillation: along the pacemaker lead, v entricular \201 brillation may be induced. Myocardial damage: another potential effect of channeling of the diathermy current along the pacemaker lead is burning of the myocardium at the tip of the pacemaker lead. This can subsequently result in ineffective pacing. if the diathermy current is channeled It was formerly recommended that a magnet was placed over the pace- maker to overcome pacem aker inhibition and to make the pacemaker function at a \201 xed rate. This can, however, result in phantom reprogramming. For demand pacemakers, it is better to program the pacema ker to a \201 xed rate (as opposed to demand pacing) for the duration of the operation. C onsult the patient \200\231s cardiologist for advice. Other precautions \200 The patient plate should be sited so that the current path does not go right through the pa cemaker. Ensure that the indifferent plate is correctly applied as an improper connection c an cause grounding of the diathermy current through the ECG monitoring leads and this can a ffect pacemaker function. The indifferent plate should be placed as close as possible to th e pacemaker (e.g. over the thigh or buttock). The diathermy machine should be placed well a way from the pacemaker and should certainly not be used within 15cm of it. The heartbeat sh ould be continually monitored and a de \201 brillator and external pacemaker should be at hand. Try to use short bursts of diathermy at the lowest effective output Use bipolar diath ermy in preference to monopolar (not practical for many urological procedures where the onl y form of diathermy that can be used is monopolar). \200 DIATHERMY 735 Give antibiotic prophylaxis (as for patients with arti \201 cial heart valves). Because th e pacemaker-driven heart will not respond to \202 uid overload in the normal way, the res ection should be as quick as possible and \202 uid overload should be avoided. Further reading Allen M (2006) Pacemakers and implantable cardioverter de \201 brillators. Anesthesia 62:8 52 \200\2233. Medicines and Healthcare Products Regulatory Agency (2006) Guidelines for the perioperative management of patients with implantable cardioverter de \201 brillators, where the use of diathermy is anticipated [online]. Available from: M http://www.mhra.gov.uk. Salukhe TV, Dob D, Sutton R (2004) Pacemakers and de \201 brillators: anesthetic implicati ons. Br J Anaesth 93:95 \200\223104. CHAPTER 17 Urological surgery and equipment 736 Sterilization of urological equipment Techniques for sterilization Autoclaving: modern cystoscopes and resectoscopes, including compo- nents such as light lea ds, are autoclavable. Standard autoclave regimens heat the instruments to 121 C for 15min or 134 C for 3min. Chemical sterilization: this involves soaking instruments in an aqueous solution of chlorine dioxide (Tristel), an aldehyde-free chemical (there has been a move a way from formaldehyde because of health and environmen- tal concerns). Chlorine dioxide sol utions kill bacteria, viruses (including HIV and hepatitis B and C), spores, and mycobacter ia. Cameras cannot be autoclaved. Use a camera sleeve or sterilize camera between cases in solutions such as Tristel. Sterilization and prion diseases Variant CJD (vCJD) is a neurodegenerative disease caused b y a prion pro- tein (PRP). Other examples of neurodegenerative prion diseases include class ic CJD, kuru, sheep scrapie, and bovine spongiform encephalopathy (BSE). Variant CJD and BS E are caused by the same prion strain and repre- sent a classic example of cross-species tr ansmission of a prion disease. There has been much recent concern about the potential for trans- mission of vCJD between p atients via contaminated surgical instruments. Classic CJD may be transmitted by neurosurgi cal and other types of surgi- cal instruments because normal hospital sterilization procedu res do not completely inactivate prions.1 It is not possible at present to quantify the ris ks of transmission of prion diseases by surgical instruments. To date, iatrogenic CJD remai ns rare, with 267 cases having been reported world- wide up to 2000.2 The risk of transmission of CJD may be higher with procedures per- formed on organs contain ing lymphoreticular tissue, such as tonsillectomy and adenoidectomy, because vCJD targets t hese tissues and is found in high concentrations there. For this reason, there was a move t owards the use of disposable, once-only-use instruments for procedures such as ton- sillect omy. However, these instruments have been associated with a higher post-operative hemorrhag e rate3 and as a consequence, ENT depart- ments in the UK are no longer obliged to use disp osable instruments. In the UK, the Advisory Committee on Dangerous Pathogens and Spongiform Encephalopathy4 pro vides advice on appropriate methods of cleaning and sterilization of surgical instruments. Prions are particu- larly resistant to conventional chemical (ethylene oxide, formaldehyde, and chlorine dioxide) and standard autoclave regimens, and dried blood or tissue remaining on an instrument could harbor prions that will not then be killed by the sterilization pro cess. Once proteinaceous material such as blood or tissue has dried on an instrument, it is very dif \201 cult to STERILIZATION OF UROLOGICAL EQUIPMENT 737 subsequently be sure that the instrument has been sterilized. Sterilization should include: \200 Pre-sterilization cleaning: with detergents and an ultrasonic cleaning system removes and p revents coagulation of prion proteins \200\224sonic cleaners essentially \200\230shake \200\231 attached material from the instrument. Hot wash. Air drying. Thermal sterilization : longer autoclave cycles at 134 \200\223137 C for at least 18min (or six successive cycle s with holding times of 3min) or 1h at conventional autoclave temperatures may result in a substantial reduction in the level of contamination with prions. initial low temperature washing (<35 C) \200 \200 The latest models of pre-sterilization cleaning devices \200\224automated ther- mal washer disinfectors \200\224perform all of these cleaning tasks within one unit. Enzymatic proteolytic inactivation methods are under development. 1 Collinge J (1999) Variant Creutzfeldt-Jakob disease. Lancet 354:317 \200\22323. 2 Collins SJ, Lawson VA, Masters CL (2004) Transmissible spongiform encephalopathies. Lance t 363:51 \200\22361. 3 Nix P (2003) Prions and disposable surgical instruments. Int J Clin Pract 57:678 \200\223 80. 4 The Advisory Committee on Dangerous Pathogens and Spongiform Encephalopathy (1998) Transm issible spongiform encephalopathy agents: safe working and the prevention of infection. Lon don: HM Stationery Of \201 ce. CHAPTER 17 Urological surgery and equipment 738 Telescopes and light sources in urological endoscopy There are three types of modern urolog ical telescopes \200\224rigid, semi-rigid, and \202 exible. These endoscopes may be used for inspection of the urethra and bladder (cystoscourethroscopes \200\224usually simply cal led cystoscopes), the ureter and collecting system of the kidney (ureteroscopes and ureter- orenoscopes), and via a percutaneous access track, the kidney (nephro- scopes). The light sources and image transmission systems are based on the innovative work of Professor Harold Hopkins from the University of Reading. The Hopkins rod-lens system Introduced by Professor Harold Hopkins in 1959. The great advan ce in telescope design was the development of the rod-lens telescope which replaced the con ventional system of glass lens with rods of glass,separated by thin air spaces which, essen tially, were air lenses (Fig. 17.13). By chang- ing the majority of the light transmission medium from air to glass, the quantity of light that could be transmitted was doubled. The rods of glass were also easier to handle during manufacture and therefore, their optical qu ality was greater. The angle of view of the telescope can be varied by placing a prism behind the objective lens. 0 , 12 , 30 ,* and 70 scopes are available. Lighting Modern endoscopes (urological and those used to image the GI tract) use \201 bre optic light bundles to transmit light to the organ being inspected (developed by Karl Stor z). Each glass \201 bre is coated with glass of a differ- ent refractive index so that li ght entering at one end is totally internally re \202 ected and emerges at the other (Fig. 17.14). These \201 bre optic bundles can also be used for image (as well as light) trans mission as long as the arrangement of the \201 bres at either end of the instrument is th e same (coordinated \201 bre bundles are not required for simple light transmission). The \201 bre bundles are tightly bound together only at their end (for coor- dinated image t ransmission). In the middle, the bundles are not bound \200\224 this makes the instrument \202 exible (e.g. \202 exible cystoscope and \202 exible ureteroscope). Digital image capture systems Conventional analog camera systems have a 3-chip camera with separate sensors for red, green, and blue colors. They convert analog data into digital dat a for image storage and enhancement. Image distortion can reduce image quality (a \200\230 spectrum \200\231 effect can occur \200\224bands of red, green, and blue across the image). A recent innovation in scope design is chip miniaturization which allows these sensors to be placed at the tip of the \202 exible cystoscope or \202 exible ureteroscope so allow ing a totally digital imaging system (as in a digital camera). The resolution and image qua lity is superior to analog systems. TELESCOPES AND LIGHT SOURCES IN UROLOGICAL ENDOSCOPY 739 (a) Glass AIR Glass Air (b) Fig. 17.13 (a) Diagram of conventional cystoscope. The glass lenses are held in place by me tal spacers and separated by air spaces; (b) Rod-lens telescope with \200\230lenses \200 \231 of air, separated by \200\230spaces \200\231 of glass, with no need for metal spacers . (Reproduced from Blandy J, Fowler C (1995) Urology. Oxford: Blackwell Science, pp. 3 \200 \2235, with permission from Wiley Blackwell.) Fig. 17.14 Total internal re \202 ection permits light to travel along a \202 exible gla ss \201 bre. (From Blandy and Fowler 1996, reproduced with permission from Wiley Blackwel l.2) In days gone by, when a tiny lamp at the end of the telescope was used for illumination, it was necessary to have a slightly angled line of vision, otherwise the light bulb got in th e way of the view. The 30 scope is a throw back to this historical requirement. CHAPTER 17 Urological surgery and equipment 740 Consent: general principles Consent is required before you examine, treat, or care for a co mpetent adult (a person aged 16 or more). Think of obtaining consent as a process rather than an event. In order to give consent, a p atient must understand the nature, purpose, and likely effects (outcomes, risks) of the tre atment. From the information they receive, the patient must be able to weigh up the risks a gainst bene \201 ts and so arrive at an informed choice. They must not be coerced into mak ing a decision (e.g. by the doctor in a hurry). Giving the patient time to reach a decision is a good way of avoiding any accusation that they were pres- sured into a decision. To re iterate \200\224think of consent as a process rather than an event. Giving information and level of disclosure How much information should you give? What optio ns and risks should you mention? The adequacy of your consent will be judged against the Bo lam test: \200\230A doctor is not guilty of negligence if he acted in accordance with a pr actice accepted by a responsible body of medical men skilled in that particular art \200 \231. (That body of medical men must be a competent and reasonable body and the opinion exp ressed must have a logical basis \200\224the Bolitho modi \201 cation of the Bolam defense .) You have a duty to discuss the range of treatment options available (the alternatives), reg ardless of their cost, in a form the patient can understand and the side effects and risks that are relevant to the individual patient \200\231s circumstances. A risk is de \201 ned as a material one (one that matters, one that is impor- tant) if a r easonable person in the patient \200\231s circumstances, if warned of that risk, would atta ch signi \201 cance to it (e.g. loss of the tip of a little \201 nger may be of little l ong-term consequence to many people, but for the concert pianist, it could be a disaster). In the words of Lord Scarman, disclosure is necessary: \200\230 where the risk is such that in the court \200\231s view, a prudent person in the patient \200\231s situation would have regarded it as signi \201 cant. \200\231 Thus, the amount and type of information you give is different in every case. Just because there is a less than 1 in 100 chance of a particular risk materializing does not mean you n eed not warn about this particular risk: \200\230When one refers to a \200\230signi \201 cant risk \200\231, it is not possible to talk in precise percentages. \200\231 (Lord Woolf in Pearce vs United Bristol HA 1996.)1 The obvious example is the need to warn of post-vasectomy pregnancy which occurs very infre quently (1 in 3000 cases). Failure to warn of such a risk would nowadays be regarded as sub standard care. Remember, it can be argued that the consent was not valid because the amount of information you gave was not enough or was in a form the patient could not understand. CONSENT: GENERAL PRINCIPLES 741 Recording Remember, record the consent discussion in the notes. If you do not record what y ou said, you might as well not bother saying it. If a patient later claims that they were n ot told of a particular risk or outcome, it will be dif \201 cult to refute this if your n otes do not record what you said. Writing \200\230risks explained \200\231 is inadequate. When cases do come to court, this is usually sev- eral years after the events in question. You will have forgotten precisely what you said to the patient and it will not take much ef fort on the part of a barrister to suggest that you might not have said everything that you thought you said! If you give a written information sheet, record that you have done so an d put a copy of the version you gave in the notes. The consent form The consent form is designed to record the patient \200\231s decision and to some extent, the discussions that took place during the consent process (although the sp ace available for recording the discussion, even on the new NHS consent form, is limited). It is not proof that the patient was properly informed \200\224that valid consent was obtai ned. Avoid, if possible, technical abbreviations such as TURBT. A patient could reasonably claim not to have understood what this was. Try to avoid standing over the patient waiting for them to sign the form. It is a good practice to leave the form with them and to return after a few minutes \200\224they will feel less pressured and can ask further questions if they wish. Children Children aged less than 16 may give consent as long as they fully under- stand wha t is involved in the proposed examination or treatment (a parent cannot override the compet ent child \200\231s consent to treatment). However, a child cannot refuse consent to treatm ent (i.e. a parent can override a child \200\231s refusal to consent \200\224the parent can consent on the child \200\231s behalf if the child refuses consent, although such situatio ns are rare). 1 Pearce and another v. United Bristol Healthcare NHS Trust, 48 BMLR 118. 1996. CHAPTER 17 Urological surgery and equipment 742 Cystoscopy A basic skill of the urologist. Allows direct visual inspection of the urethra a nd bladder. Indications \200 Haematuria. \200 Irritative LUTS (marked frequency and urgency) where intravesical pathology is suspected (e.g. carcinoma in situ, bladder stone). For bladder bi opsy. Follow-up surveillance of patients with previously diagnosed and treated bladder canc er. Retrograde insertion of ureteric stents and removal. Cystoscopic removal of stones. \200 \200 Technique \200 Flexible cystoscopy: \202 exible cystoscope is easily passed down the urethra and into th e bladder following instillation of lubricant gel (with or without local anesthetic \200 \224a meta-analysis of nine RCTs showed no difference in pain control between lidocaine gel and plain gel lubrication).11 Principally diagnostic, but small biopsies can be taken with a \202 exible biopsy forceps, small tumors can be fulgurated (with a diathermy probe) or vaporized (with a laser \201 bre), and JJ stents can be inserted and removed using this type of cystoscope. Rigid cystoscopy: rigid metal instrument which can be passed under loca l anesthetic in women (short urethra), but usually requires general anesthetic. Preferred o ver \202 exible cystoscopy where deeper biopsies will be required or as an antecedent to TURBT or cystolitholapxy where it is anticipated that other pathology will be found (tumor, stone). The \202 exible cystoscope uses \201 bre optics for illumination and image trans- missi on. It can be de \202 ected through 270 . Common post-operative complications and their management Mild burning discomfort and haemat uria are common after both \202 exible and rigid cystoscopy. It usually resolves within h ours. Bacteriuria after \202 ex- ible cystoscopy occurs in about 8 \200\2239% of patients (4 \200\2235% have bacteriuria before cystoscopy) and this rate is reduced by prophylactic antibiotics (see Table 17.1). BAUS procedure-speci \201 c consent form: recommended discussion of adverse events Serious or frequently occurring complications of \202 exible cystoscopy Warn the patient that if the cystoscopy is being done because of hae- maturia, it is possible that a bladder cancer may be found, which may require further treatment. You should speci \201 cally seek conse nt for biopsy (removal of tissue if an abnormality is found). CYSTOSCOPY 743 Common \200 Mild burning or bleeding on passing urine for a short period after operation. Biopsy of an abnormal area in the bladder may be required. Occasional \200 Rare \200 \200 \200 Infection of bladder requiring antibiotics. Temporary insertion of a catheter. Delayed bleeding requiring removal of clots or further s urgery. Injury to urethra causing delayed scar formation (a stricture). Serious or frequently occurring complications of rigid cystoscopy \200 \200 \200 As for \202 exible cystoscopy. The use of heat (diathermy) may be required to cauterize b iopsy sites. Very rarely, perforation of the bladder can occur, requiring temporary inserti on of a catheter or open surgical repair. 1 Patel AR, Jones JS, Babineau D (2008) Lidocaine 2% gel versus plain lubricating gel for p ain reduction during \202 exible cystoscopy: a meta-analysis of prospective, randomized c ontrolled trials. J Urol 179:986 \200\22390. CHAPTER 17 Urological surgery and equipment 744 Transurethral resection of the prostate (TURP) Indications \200 Bothersome LUTS which fail to respond to changes in lifestyle or medical therapy. Recurrent acute urinary retention. Renal impairment due to BOO (high-pressure retention). Recurrent haematuria due to BPE. Bladder stones due to prostatic obstruction. \200 chronic urinary \200 Post-operative care A 3-way catheter is left in situ after the operation, through which irr igation \202 uid (normal saline) is run to dilute the blood so that a clot will not form to block the catheter. The rate of in \202 ow of the saline is adjusted to keep the out \202 ow a pale pink ros color and as a rule, the rate of in \202 ow can be cut down afte r about 20min. The irrigation is continued for 12 \200\22324h. The catheter is removed the day after (second post-operative day) if the urine has cleared to a normal color (TWOC or t rial of void (TOV)). Common post-operative complications and their management Blocked catheter post-TURP Common