Материал: Oxford American Handbook of Urology ( PDFDrive )

URETEROSCOPES AND URETEROSCOPY 647

Ureteric dilatation

Some surgeons use this, others don’t. Those who don’t, argue that dilatation is unnecessary in the era of modern, small-caliber ureteroscopes. Those who do, cite a higher chance of being able to pass the ureteroscope all the way up to the kidney. Ureteric dilatation may be helpful when multiple passes of the ureteroscope up and down the ureter are going to be required for stone removal (alternatively, use a ureteric access sheath).

Some surgeons prefer to place two guide wires into the ureter, one to pass the ureteroscope over (“railroading”) and the other to act as a safety wire, so that access to the kidney is always possible if difficulties are encountered. The second guide wire is most easily placed via a dual-lumen catheter that has a second channel, through which the second guide wire can be easily passed into the ureter, without requiring repeat cystoscopy. This dual lumen catheter has the added function of gently dilating the ureteric orifice to about 10 Fr. There is probably no long-term harm done to the ureter as a consequence of dilatation.1

Ureteric access sheaths, which have outer diameters from 10 to 14 Fr, may facilitate access to the ureter and are particularly useful if it is anticipated that the ureteroscope will have to be passed up and down the ureter on multiple occasions (to retrieve fragments of stone). In addition, they facilitate the outflow of irrigant fluid from the pelvis or the kidney, thereby maintaining the field of view and decreasing intrarenal pressures.

Patient position

The patient is positioned as flat as possible on the operating table to “iron out” the natural curves of the ureter. A cystoscopy is performed with either a flexible or rigid instrument. A retrograde ureterogram can be done to outline pelvicalyceal anatomy.

A guide wire is then passed into the renal pelvis. We use a Sensor guide wire (Microvasive, Boston Scientific), which has a 3 cm long floppy, hydrophilic tip that can usually easily be negotiated up the ureter. The remaining length of the wire is rigid and covered in smooth PTFE.

Both properties aid passage of the ureteroscope.

Technique of flexible ureteroscopy and laser treatment for intrarenal stones

Flexible ureteroscopy and laser treatment can be performed with topical urethral local anesthesia and sedation. However, trying to fragment a moving stone with the laser can be difficult and, ideally, ureteroscopy is most easily done under general anesthesia with endotracheal intubation (rather than a laryngeal mask) to allow short periods of suspension of respiration and so stop movement of the kidney and its contained stone.

Empty the bladder to prevent coiling of the scope in the bladder. Pass the scope over a guide wire. This requires two people—the surgeon holds the shaft of the scope and the assistant applies tension to the guide wire to fix the latter in position without pulling it down. This allows the scope to progress easily up the ureter.

1 Emberton M, et al. (1995). The National Prostatectomy Audit: the clinical management of patients during hospital admission. Br J Urol 75:301–316.

648 CHAPTER 16 Urological surgery and equipment

The assistant also ensures that acute angulation of the scope where the handle meets the shaft does not occur. The flexible ureteroscope should slide easily up the ureter and into the renal pelvis.

With modern active secondary deflection ureteroscopes, access to most, if not all, parts of the renal collecting system is possible.

Laser lithotripsy

The main drawback of laser lithotripsy is the dust cloud effect that occurs as the stone is fragmented. This temporarily obscures the view and must be washed away before the laser can safely be reapplied.

To stent or not to stent after ureteroscopy

JJ stent insertion does not increase stone-free rates and is therefore not required in routine cases. A stent should be placed if

•There has been ureteric injury (e.g., perforation—indicated by extravasation of contrast)

•There are residual stones that might obstruct the ureter

•The patient has had a ureteric stricture that required dilatation

•There are solitary kidneys

Routine stenting after ureteroscopy for distal ureteric calculi is unnecessary.2 Many urologists will place a stent after ureteroscopy for proximal ureteric stones.

Complications of ureteroscopy

These include septicemia; ureteric perforation requiring either a JJ stent or, very occasionally, a nephrostomy tube where JJ stent placement is not possible; and ureteric stricture (<1%).

P rocedure-specific consent form—recommended discussion of adverse events

Serious or frequently occurring complications of ureteroscopy for treatment of ureteric stones

Common

•Mild burning or bleeding on passing urine for a short period after the operation

•Temporary insertion of a bladder catheter may be required.

•Insertion of a stent may be required with a further procedure to remove it.

•Urinary infections occasionally requiring antibiotics

Occasional

•Inability to get stone or movement of stone back into kidney when it is not retrievable

•Kidney damage or infection requiring further treatment

•Failure to pass scope if ureter is narrow

•Recurrence of stones

2 Srivastava A, et al. (2003). Routine stenting after ureteroscopy for distal ureteral calculi is unnecessary: results of a randomized controlled trial. J Endourol 17:871.