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Keywords:

  • kidney;
  • percutaneous;
  • percutaneous nephrolithotomy (PCNL);
  • dilatation;
  • nephroscope

Introduction

  1. Top of page
  2. Introduction
  3. Technique
  4. Comments
  5. References

During percutaneous renal tract creation in normally fixed kidneys, the puncture needle, dilators and sheath enter the renal parenchyma smoothly. However, when the kidney is abnormally mobile, it is pushed by the puncture needle and particularly by the dilators. Thus, when the dilators meet the resistance of the renal capsule, insisting to enter the parenchyma will lengthen the percutaneous tract [1]. This causes wide kinking of the guidewire, making dilator progression difficult [2]. Consequently, tract dilatation becomes time consuming with increased radiation exposure. To overcome this problem, we use a complement to ‘one-shot’ dilatation [3] by using bi-prong forceps to perform dissection of the renal parenchyma under direct vision and without radiation exposure.

Technique

  1. Top of page
  2. Introduction
  3. Technique
  4. Comments
  5. References

For percutaneous surgery, the patient is placed in the split-leg modified lateral position [4]. Tract dilatation is mostly performed directly using ‘one-shot’ dilatation with an Amplatz dilator and a 24 F sheath. In case of a mobile kidney, which is pushed by the dilator; without insisting (or persevering), the Amplatz sheath and dilator are stopped in contact with the renal capsule (Figure 1A and B). The Amplatz dilator is retrieved and the nephroscope is advanced alongside the guidewire. The renal puncture site with one or two guidewires is located (Figure 2A). The tip of the bi-prong forceps is inserted in the renal capsule breach (Figure 2B). It is then opened and used to progressively widen the renal capsule and the parenchyma tunnel by blunt dissection (Figure 3A and B). The forceps is turned 90 ° and opened once again. It is then closed and advanced into the renal tunnel. The procedure is repeated in a similar manner (Figure 4A) until the calyceal cavity is reached. The nephroscope and then the Amplatz sheath are smoothly advanced over the forceps with a rotating motion until the calyceal cavity is reached (Figure 4B). Occasionally the renal tunnel is barely dilated, even to 10 F, and the insertion of the safety guidewire is almost impossible. In this case, a forceps with a narrow tip is used until the tunnel is wide enough for larger forceps. On rare occasions the Amplatz dilator and sheath cannot even dilate the retro-renal fascia. In this case, forceps dilatation is used to widen the retro-renal fascia, and then the renal tunnel.

figure

Figure 1. A. The targeted calyx is punctured and then the working guidewire and the safety guidewire are inserted.

B. In case of a mobile kidney, which is pushed by the dilator; without insisting or persevering, the Amplatz sheath is stopped in contact with the renal capsule.

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figure

Figure 2. A. The nephroscope is advanced through the Amplatz sheath alongside the guidewire. The renal puncture site with two inserted guidewires is located.

B. Endoscopic view: The dissection of the renal parenchyma is performed under direct vision with no need for radiation exposure. The tip of the alligator forceps is inserted in the gap of the renal capsule and parenchyma tunnel beside the guidewires.

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figure

Figure 3. A. The alligator forceps is opened, progressively widening the renal capsule and the parenchyma tunnel.

B. Endoscopic view: The two jaws of the forceps spreading the renal capsule.

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figure

Figure 4. A. The alligator forceps is slowly moved forward in the renal tunnel, opening the way using a succession of ‘open and close’ of its jaws. The nephroscope is gradually advanced over the forceps. The Amplatz sheath is then advanced over the nephroscope.

B. When the calyceal cavity is reached, the nephroscope and then the Amplatz sheath are move forward into the calyx.

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Comments

  1. Top of page
  2. Introduction
  3. Technique
  4. Comments
  5. References

This bi-prong technique was initially performed in cases of stone occupying the entire calyx of entry, so as not to perform dilatation beside the stone, which might lead to calyceal or infundibular lacerations [5]. However, this procedure was first used to surmount renal mobility in large hydronephrosis with thin renal parenchyma, where it seemed easier and safer with less haemorrhagic risk. Yet, as expected, during dilatation of large parenchyma there is bleeding and usually the calyceal cavity is occupied with blood clots [6]. However, like with other means of dilation, the advance of the Amplatz sheath tamponade the bleeding and the clots are aspirated using the vacuum technique [7]. In fact, once the Amplatz sheath is placed, no difference in bleeding was noted compared with other dilatation methods. Furthermore, with other dilatation systems, over-advancement of the dilator and sheath in the accessed calyx may result in significant trauma to the renal collecting system and/or excessive haemorrhage [8]. As the dilatation in our technique is performed under direct vision, this problem of over-advancement was not noted.

A similar technique has been reported for percutaneous access to small calyceal diverticulum. After balloon tract dilatation, the working sheath is placed outside the diverticulum; then an alligator forceps is used to spread the outer wall of the diverticulum under direct vision [8].

The use of a balloon dilatation catheter, if it can be appropriately positioned, may indeed help to avoid the problem of renal mobility during dilatation [1]. Otherwise, in the prone position, during a planned percutaneous nephrolithotomy in a floating kidney, Goldfischer et al. [9] made a single tract with insertion of a balloon catheter, which was then used to retract and stabilise the kidney, allowing accurate further punctures for stone removal. Similarly, in the supine position, Valdivia et al. [10] and Shoma et al. [1] used extra-abdominal compression during dilatation of these tracts to minimise renal movement. De Sio et al. [2] found that the use of a Lunderquist guidewire was particularly helpful to stabilise the kidney.

The main advantage of our technique is that the dissection of the renal parenchyma is performed under direct vision with no need for radiation exposure. In addition, it might be faster than other techniques. This technique is another addition to the urologist's arsenal, to surmount the problem of renal mobility during tract formation.

References

  1. Top of page
  2. Introduction
  3. Technique
  4. Comments
  5. References
  • 1
    Shoma AM, Eraky I, El-Kenawy MR, El-Kappany HA. Percutaneous nephrolithotomy in the supine position: technical aspects and functional outcome compared with the prone technique. Urology 2002; 60: 388392
  • 2
    De Sio M, Autorino R, Quarto G et al. Modified supine versus prone position in percutaneous nephrolithotomy for renal stones treatable with a single percutaneous access: a prospective randomized trial. Eur Urol 2008; 54: 196202
  • 3
    Frattini A, Barbieri A, Salsi P et al. One shot: a novel method to dilate the nephrostomy access for percutaneous lithotripsy. J Endourol 2001; 15: 919923
  • 4
    Lezrek M, Ammani A, Bazine K et al. The split leg modified lateral position for percutaneous renal surgery and optimal retrograde access to the upper urinary tract. Urology 2011; 78: 217220
  • 5
    Gupta M, Ost MC, Shah JB, McDougall EM, Smith A. Percutaneous management of the upper urinary tract. In: Wein AJ , Kavoussi LR , Novick AC , Partin AW , Peters CA eds, Campbell-Walsh Urology, 9th edn. Philadelphia: Saunders, 2007: 15261563
  • 6
    Lezrek M, Qarro A, Moufid K et al. VID-06.08 Techniques to overcome renal mobility during percutaneous tract creation. Urology 2011; 78 (Suppl.): 174
  • 7
    Lezrek M, Qarro A, Bazine K et al. A vacuum cleaner for the pelvicalyceal system during percutaneous nephrolithotomy. J Endourol 2010; 24: 949952
  • 8
    Lingeman J, Lifshitz D, Evan A. Surgical management of urinary lithiasis. In: Walsh PC , Retik AB , Vaughan ED , Wein AJ eds, Campbell's Urology, 8th edn. Philadelphia: Saunders, 2002: 398416
  • 9
    Goldfischer ER, Al-Kandari AM, Baernardo NO et al. Percutaneous surgery in a patient with nephroptosis. J Urol 1999; 161(Suppl.): 395
  • 10
    Valdivia Uria JG, Valle Gerhold J, Lopez Lopez JA et al. Technique and complications of percutaneous nephroscopy: experience with 557 patients in the supine position. J Urol 1998; 160: 19751978