RIRS

Retrograde Intrarenal Surgery(RIRS)HistoryHugh H. Young (1912): endoscopic view of the ureters.Hirshowitz et al. (1956): 1st flexible esophagogastroduodenoscopyMarshall (1964): flexible ureteroscopy by 3 mm fiberscopeTagaki et al. (1968): passed similar scope through an open ureterotomy into the PCS.

INSTRUMENTATIONsFlexible ureterorenoscopeVideo cameraFluoroscopic support

Accessory instruments:Guide wiresUreteral dilatorsAccess sheathBasketUreteric cathetersFiberopticsMade from molten glass/quartz. Each fiber in the bundle is approx. 8 m in diameter. Uniformly transmits light from one end to the other.These fibers are bundled together in the same orientation (coherent). Which allows these dots of light to coalesce and transmit the resultant image.CladdingA second layer of dissoluble glass is evenly dispersed between the fiberoptic fibers.Different RI than the core glass.Interface between these two different glasses produces the internal reflection- Better image preservation. Allows for softening and flexibility of the whole bundle.

Morea effectCladding doesnt transmit light

This distribution known as pixel spacing

also responsible for the mesh-like appearance of the image or insect-eye pattern.

A distal and proximal optical lens transforms the fiberoptic bundle into a clinical telescope.

Angle of viewCan be modified by changing the axis of the optical system at the tip. Usually accomplished with a wedge lens system at the distal end of the imaging bundle. This modified angle of view can be up to 10 degrees in fluid.Help in visualizing working instruments as they emerge from the tip of the scopeLight transmissionSource lamp: Halogen (150 watts)Xenon (300 watts)

Flexible light cord, which is also made up of fiberoptic bundles, transmits the light to the ureteroscope.

Drawbacks of flexible fiberoptics limited field of view compared with the rod-lens optical system of the rigid endoscopes.

focusing mechanisms and image magnification to compensate for that loss.

Digital endoscopesDifferent from their analog counterparts with no fiberoptic cable or viewing ocular lens. Instead, the image seen at the distal tip of the scope is electronically and digitally transferred through a single cable.and recreated on a televisions monitor.Image capture sensersCCD (Couple charged devise), 1970:-

Microchip that could store electric charge.storage of data that could be retrieved at a later time.CMOS (complementary metal oxide semiconductor), 1967:-

low-cost storage alternativeBoth CCD and CMOS devices are digital sensors composed of millions of photodiodes.Convert photons into electric current that is transformed into a voltage, amplified, and converted to a digital form The image is digitally transferred via a single cable to a distant processor, which reconstructs and enhances the image electronically on a televisionIn 2005 the first commercially available distal sensor endoscope was the ACMI DCN-2010 digital cystoscope.

With a digital camera and light emitting diode (LED)Digital endoscope benefitsbetter image qualityimproved contrast resolutioncolor discriminationlighter scopeless cablingimproved ergonomicsDeflection MechanismACTIVEPrimarySecondary

PASSIVEActive deflectionsLever controlled, which shortens or lengthens wires running to metal rings just proximal to the tip.

Cause the deflection in both directions in one plane.

Essential to access the lateral and inferior infundibula

intuitive:- when the tip moves in the same direction as the lever (an upward deflection on the handle lever deflects the scope upwards, and vice versa).

counterintuitive:- (an upward deflection on the handle deflects the scope tip downward).

ACMI DUR8-E flexible ureteroscopeTwo levers to control active deflection at two separate sites near the tip of the scope.

The primary active deflection allows for up to 185 of downward deflection,

While adding the secondary active deflection allows for a total of 270 in one direction.

No passive deflection is available with this.

Karl Storz has developed a different mechanism on their latest flexible ureteroscope. A single-lever mechanism that offers dual 270 of deflection.

Secondary passive deflectionResult of making the segment just proximal to the point of active deflection more flexible.

Passive deflection off the wall of the renal pelvis moves the point of deflection proximally on the scope.

How to improve active deflectionStraight alignment of proximal shaft of the ureteroscope.Access sheath in preventing buckling of the ureteroscope.Holding the ureteroscope taut by gentle manual back tension on shaft.Placing a super-stiff guidewire in the working channel & positioning the guidewire tip 2 cm proximal to the end of the ureteroscope. (only in diagnostic procedures)Deflection is inhibitedWhen larger-diameter accessories are passed through the working channel.

Working channelFlexible ureteroscopes have a single working channel.

This allows fluid irrigation and passage of instruments.

A smooth cylindrical plastic tube that travels trough the flexible ureteroscope.

Most working channels are 3.6F in diameter and are eccentrically located.

Newer, smaller-tip ureteroscopesthe eccentricity is less prominent.

Allows for less distortion of the working channel while actively deflecting, and allows easier passage of working

Passage of working instruments may be difficult when the scope is maximally deflected.

Working channel may be damaged if passage is attempted while the scope is deflected.

Passing instruments is best accomplished with the scope straightened and adequately lubricating the instruments.Different scopes available

Guide WiresTraditionally, 2 guidewires were required to perform flexible ureteroscopy.

Safety guidewire,

Second is used to facilitate endoscope placement. Double flexible-tips guide-wire is essential for scope introduction.

0.035 or 0.038 inch x 150 cm hybrid guide wire [Sensor (Boston Scientific)]its flexible, hydrophilic tip minimizes traumaallows easy access around upper urinary tract stones and obstruction, kink-resistant & sufficient rigidity of shaft to act as a working wire. Standard 0.035G/0.038G PTFE-coated floppy tip guide-wire:-

Used for the placement of ureteric catheters, introducing dilators / Access sheath Serve as safety guide-wire

Ureteral dilatorsPolyethylene or PTFE coaxial dilatorsrange in size from 6F to 18F and

are sequentially passed over a wire under fluoroscopic vision across the narrow segment.

Balloon dilatorsdeflated shaft diameter of 5F,

balloon lengths between 4 and 10 cm,

Inflated profile of 1230F.Placed over a super-stiff or hybrid wire across the area of interest.

Inflated up to 20 atm of pressure

with diluted contrast with a specially designed [Le Veen (Boston Scientific)] pressure gauge syringe.

Other methodsVisual dilatation by Semirigid Ureteroscope.

The inner dilator of access sheath can be used without the outer sheath to dilate the ureter over a super-stiff guidewire.

Ureteral access sheathsOuter diameter:- 9 to 18 Fr Length:- 20 to 55 cm.12/14F is the standard size (adults)If the goal is to reach the UPJ:35-cm length sheath for women 45-cm length sheath for menFacilitate expeditious and atraumatic entry and re-entry.

Eliminating the risk of buckling of the endoscope in the bladder.

Protects the upper urinary tract from increased peak intrarenal pressure.BenifitsDecreases the risk of endoscope damage.Decrease operative time and cost, minimize patient morbidity,Optimize overall success of flexible ureteroscopy.no level 1 evidence exists to support or refute their use.advocate ureteral stent placement in cases in which a ureteral access sheath has been used.

Intra corporeal lithotritesElectrohydraulic lithotrite.

Holmium(Ho):YAG laser

Holmium(Ho):YAG laserShown to fragment all compositions of urinary calculi.

produce smaller stone fragments than pneumatic or electrohydraulic lithotripsy.

energy is absorbed efficiently in a fluid medium, minimizing the risk of urothelial injury.EHLgenerates a spark which results in plasma expansion at supersonic speed,

Propagating a hydraulic shock wave and cavitation bubble. Collapse of the cavitation bubble leads to a second shock wave, which if asymmetric leads to the formation of a liquid jet.

Each of these mechanisms results in stone fragmentation.Tipless Nitinol basketsNitinol baskets preserve the tip deflection.

tipless design reduces the risk of mucosal injury.

Nitinol baskets are the only baskets suitable for use in RIRS. [EAU]

Complications of basketing Ureteral avulsionIntussusceptionAbrasionPerforationPostoperative stricture formationBasket breakage or entrapmentPreventing basketing-related complicationsAvoidance of forceful basket manipulationLimiting retrieval to calculi or fragments that are small enough to be easily extracted with minimal trauma Direct visualization of the basket and its contents at all timesAvoiding contact of the laser with the basketGraspersFor the removal of

Retained stents, Foreign bodies, embedded stones.

Endoirrigation systems20 mL/min provide adequate visualization in most circumstances.

Types:

Gravity basedHand held syringeAutomated irrigation system

Gravity with or without the assistance of pressure-bag compression is commonly utilized.

With the use of a ureteral access sheath, intrarenal pressures can be maintained below 30 cmH2O even with systems pressurized to 200 cmH2O.IndicationsRIRSDIAGNOSTIC APPLICATIONSEvaluation and localization of hematuria.Evaluation and localization of positive cytology.Evaluation of filling defects seen on contrast studies.Investigation of positive cultures localized to a specific urinary tract.Surveillance for TCC cases of the upper tract managed endoscopically.THERAPEUTIC APPLICATIONSEndoscopic LithotripsyRx of upper tract urothelial TCCRemoval of foreign bodies located in upper tractRx of UPJO by endopyelotomyPRE OP EVALUATIONPatient history.Physical examination, because anatomical and congenital abnormalities may complicate or prevent retrograde stone manipulation.Platelet aggregation inhibitors/anticoagulants should be discontinued if possible.[URS can be performed in patients with bleeding disorders, with a moderate increase in complications]Imaging.CONTRAINDICATIONSUntreated UTI

URS can be performed in all patients without any specific contraindications.

Specific problems such as ureteral strictures may prevent successful retrograde stone management.AnesthesiaLA is adequate only when using smaller flexible endoscopes for surveillance.

GA, preferred than regional anesthesia.provides better pain control when working in the proximal ureters or collecting system.provides a relaxed patient, eliminating harmful sudden movements

PositionStandard lithotomy position.

The leg contralateral to the side of interest is slightly extended and the hip abducted.

This allows minimal angulation of the ureters.

If necessary, may be done in the prone position as during PCNL.Ureteric accessSafe accessCystoscopy

RGP (to assess course of ureter)

Manipulation of safety wire into kidney.

2nd working wire introduction.

Administration of diuretic (Reduces risk of pyelorenal reflux and septic complications)Flexible URSOptical dilation with 9.5 Fr. Semi rigid ureteroscope.

Introduction of flexible ureteroscope into ureter alongside safety guide wire over second working guide wire.

Empty bladder if all else fails, consider dilation of ureteral orifice.Scope introductionAfter emptying the bladder, the flexible ureteroscope is back loaded over the working guidewire in a monorail fashion under fluoroscopic guidance.

It should be kept straight and in direct line with the wire.

The scope is passed up like a catheter, free from any auxiliary attachments.

Straighten urethra and avoid kinking.

Advance scope with thumb and index finger of left hand.

Ureteroscope tip designWhen an eccentrically placed working channel is present, rotation of the shaft may be required to orient the working channel of the instrument to the 12-oclock position. prevent the lens from catching the roof of the orifice & telescoping the distal ureters during passage.

The newer-designed tips have a more centrally located channel that obviates the need for rotation

Pass the scope over guidewire which is removed once the scope advanced past the iliac vessels/ till renal pelvis.

Safety wire is secured to the drapes.

Right Hand ActionsKeep wire under slight tension.

Up/down flection after removal of guide wire

RIRS for renal calculiPrimary RIRS Indications 10 mm).Narrow infundibulum (< 5 mm).

Cont. Primary RIRS indicationsStricture below stone (Caliceal Diverticulum/Nephrocalcinosis)

Anticoagulated patients.

Special SituationsResidual after ESWL (not fragmented/not passed)Residual after PCNL (not passed/ no access)RIRS assisted ESWL (upto 2.5cm)Staghorn stones (RIRS + ESWL using holmium debulking)Staghorn stones when ESWL/PCNL not medically feasible.LithotriptorHo:YAG laser lithotripsy is the preferred method for (flexible) URS.

200 micron fibre.Post op stentingRoutine stenting after uncomplicated URS (complete stone removal) is not necessary;

A ureteric catheter with a shorter indwelling time (1 day) may be used as well, with similar results.

Alpha-Blockers (Tamsulosin) reduce the morbidity of ureteral stents and increase tolerability. [Meta-analysis]Stents should be inserted in patients who are at increased risk of complications:-Residual fragments, bleeding, perforation, UTIs, PregnancyIn all doubtful cases, to avoid stressful emergencies.Duration of stenting favoured 1-2 weeks after URS.Rx OF UPPER URINARY TRACT UROTHELIALMALIGNANCIESIndicationsSolitary kidney, Renal insufficiency, Synchronous bilateral tumors, High operative risk, Predisposition to form multiple recurrences, such as endemic Balkan nephropathy.Patients must commit to a lifetime of follow-up:Urine cytologies, EndoscopyDiagnostic URSMaximal length seen by semirigid scope without guide wire.Guide wire paced till UPJ. Rest visualised by flexible scope.

Suspicious area biopsy or brush cytology taken.TherapeuticDebulking grasping forceps Flat wire basket[Tumor base is treated with either electrocautery or laser energy sources]

Resection by ureteroscopic resectoscope

Laser Fulguration:

Ho: YAG laser:- 0.6 to 1 J with 10 Hz.

Nd : YAG laser:- 15W for 2 seconds for ablation of tumor.

Rx OF URETEROPELVIC JUNCTION (UPJ)OBSTRUCTION ENDOPYELOTOMYBasic concept of Retrograde endopyelotomy:-

Fullthickness incision through the obstructing UPJ.

Incision is stented and left to heal, based on the concept of an open, Davis intubated ureterotomy.TechniqueScope positioned at the proximal extent of the UPJ.200- or 365- holmium fiber is placed through the working channel.UPJ is typically incised in a posterolateral direction while the scope is withdrawn back down across

repeated and deepened to extend into the peripelvic and periureteral fat.Injection of contrast material demonstrate extravasation and confirm an adequate depth of incision.Endopyelotomy stent/ 7-8F DJ stent is left across the UPJ for 4 to 8 wks. Success rate: 82 to 87 %.REMOVAL OF FOREIGN BODIES LOCATED WITHINTHE UPPER URINARYTRACTOccasionally fragments of stents, laser fibers, guidewires, or stone baskets may be left in the upper urinary tracts postinstrumentation.

Flexible ureteroscopy is used to inspect and grasp the foreign body using a three-pronged endoscopic grasper or a stone basket.COMPLICATIONSUrosepsis

Bleeding

Ureteral perforation

Ureteral avulsion

Ureteral strictures

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