**3.2.5 Access equipment**

Two commercial access systems are available, namely, trocar with a cannula and needleguidewire-catheter techniques. The trocar technique is dangerous if the collecting system is not entered at the first pass. Currently, the Seldinger-based needle-guidewire equipment is much more popular due to its safety. This equipment has two common needle sizes 18 gauge and 21-gauge.With needle size 18-gauge, 0.035 or 0.038 inch guidewire is accepted to pass into the collecting system. The 0.018-inch guidewire is for needle size 21-gauge. (Fig. 12-15)

The advantage of 18 gauge trocar needle is minimal deviation along the course of the needle. The advantages of 21-gauge needle are decreased risk of parenchymal damage, optimal size for nondilated collecting system.The soft tip of 0.018 inch guidewire is rarely perforated the collecting system. A special nephrostomy tube kit is available, containing an 18-gauge needle, guidewire, dilators, a percutaneous nephrostomy catheter size 8 Fr or 10 Fr. Angiographic method is preferable to the trocar technique because of its safety.

Fig. 11. The serial dilatation was done for

larger access tract.

The ideal imaging guidance technique for uncomplicated renal drainage is a combination of initial ultrasonography and followed by fluoroscopy for control of catheter and guidewire

The puncture can be performed into the collecting system without preoperative opacification of the collecting system. CT scan is essential in patients with organomegaly such as hepatomegaly and splenomegaly, severe skeletal abnormalities such as scoliosis and kyphosis, morbid obesity, and previous major intraabdominal surgical interventions.

Two commercial access systems are available, namely, trocar with a cannula and needleguidewire-catheter techniques. The trocar technique is dangerous if the collecting system is not entered at the first pass. Currently, the Seldinger-based needle-guidewire equipment is much more popular due to its safety. This equipment has two common needle sizes 18 gauge and 21-gauge.With needle size 18-gauge, 0.035 or 0.038 inch guidewire is accepted to pass into the collecting system. The 0.018-inch guidewire is for needle size 21-gauge. (Fig.

The advantage of 18 gauge trocar needle is minimal deviation along the course of the needle. The advantages of 21-gauge needle are decreased risk of parenchymal damage, optimal size for nondilated collecting system.The soft tip of 0.018 inch guidewire is rarely perforated the collecting system. A special nephrostomy tube kit is available, containing an 18-gauge needle, guidewire, dilators, a percutaneous nephrostomy catheter size 8 Fr or 10

Fr. Angiographic method is preferable to the trocar technique because of its safety.

Fig. 10. Nephostogram via access needle demonstrated hydronephrosis of right kidney. The second needle was introduced toward the upper calyx for upper pole percutaneous nephrolithotomy.

manipulation.

**3.2.4.4 CT guidance** 

(Haaga et al., 1977)

12-15)

**3.2.5 Access equipment** 

**3.2.4.3 Combined ultrasonography and fluoroscopy** 

Fig. 12. Commercial access systems of needle-guidewire-catheter techniques.

Fig. 13. Basic instruments for percutaneous nephrostomy tube placement.

Fig. 14. Needle and dilators.

Modern Surgical Treatments of Urinary Tract Obstruction 273





: Ureteropelvic junction obstruction (UPJO) and upper ureteral stricture

The upper pole of the kidney aligned medially and posterior to the lower pole, making the upper pole a shorter and easier access route. The upper-pole approach provides a straight tract along the long axis of the kidney and ensures the ability to reach most of the collecting system while providing easier manipulation of rigid instrument. The operative techniques of upper pole access need coordination with the anesthetists for controlling breathing for prevention of intercostals vessel and pulmonary complication. (Lojanapiwat & Prasopsuk,




: Pelvic stone

: Calyceal stone

: Staghorn stone

stone.

: Upper ureteral stone

**3.2.6.2 Upper pole access for renal access** 



Table 3. Indication for the upper pole access.

avoid injuring the blood vessels.

displacement of the kidney.

Table 4. Technique of upper pole access.

maintain low-pressure irrigation.

2006) (Table 3, 4)


: Diverticular stone

Percutaneous nephrolithotomy (PCNL)

Endopyelotomy (EP) / endoureterotomy






Fig. 15. Benson guidewire.

#### **3.2.6 Access route**

Choosing the point of entry is a very important step which can influence the final position of the nephrostomy tube. The ideal percutaneous access tract into the collecting system should begin at the posterior axillary line. The tract courses through renal parenchyma into the tip of the posterolateral calyx, and then into the middle portion of renal pelvis. This puncture line provides the stabilization of the nephrostomy tract and seals the tube that prevents urine extravasation into the perinephric space.

This technique can avoid the major bleeding due to fewer number of blood vessels at caliceal tip and this position aids subsequent endourologic manipulation such as percutanous nephrolithotomy (PCNL) or endopyelotomy. The more medially sited tract nephrostomy tube causes more discomfort for the patient in the supine position due to the compression the external portion of PNT tube with the back.

If possible, the puncture should be performed subcostally for prevention of pleural complication. In special situations, the intercostal approach may be used due to the anatomy of kidney. Upper pole approach may be needed in special situations. In ephostomy tract placement for endourologic procedures via the upper pole, the incidence of hydrothorax or hydropneumothorax is 5 to 12 percent. (Lojanapiwat & Prasopsuk, 2006). Chest tube drainage is required for patient with significant amounts of hydrothorax.

The advantages of lateral puncture are avoiding access through the bulky paraspinal muscle, ensuring the placement through the parenchyma and less chance of damaging a major vessel. Pleural complication following lateral intercostal tract is less than vertical tracts.

#### **3.2.6.1 The site of puncture depends on the indication of nephrostomy tube placement**


Percutaneous nephrostomy placement can be performed through nearly any tract. But if the patient needs permanent nephrostomy, the nephrostomy tube should be an ideal percutenous access tract for the patient's comfort.

	- Percutaneous nephrolithotomy (PCNL)
		- : Pelvic stone

Choosing the point of entry is a very important step which can influence the final position of the nephrostomy tube. The ideal percutaneous access tract into the collecting system should begin at the posterior axillary line. The tract courses through renal parenchyma into the tip of the posterolateral calyx, and then into the middle portion of renal pelvis. This puncture line provides the stabilization of the nephrostomy tract and seals the tube that prevents

This technique can avoid the major bleeding due to fewer number of blood vessels at caliceal tip and this position aids subsequent endourologic manipulation such as percutanous nephrolithotomy (PCNL) or endopyelotomy. The more medially sited tract nephrostomy tube causes more discomfort for the patient in the supine position due to the

If possible, the puncture should be performed subcostally for prevention of pleural complication. In special situations, the intercostal approach may be used due to the anatomy of kidney. Upper pole approach may be needed in special situations. In ephostomy tract placement for endourologic procedures via the upper pole, the incidence of hydrothorax or hydropneumothorax is 5 to 12 percent. (Lojanapiwat & Prasopsuk, 2006). Chest tube

The advantages of lateral puncture are avoiding access through the bulky paraspinal muscle, ensuring the placement through the parenchyma and less chance of damaging a major vessel. Pleural complication following lateral intercostal tract is less than vertical

**3.2.6.1 The site of puncture depends on the indication of nephrostomy tube placement** 

Percutaneous nephrostomy placement can be performed through nearly any tract. But if the patient needs permanent nephrostomy, the nephrostomy tube should be an ideal

Fig. 15. Benson guidewire.

urine extravasation into the perinephric space.

compression the external portion of PNT tube with the back.

percutenous access tract for the patient's comfort.

drainage is required for patient with significant amounts of hydrothorax.

**3.2.6 Access route** 

tracts.


	- ideal tract is directly through the stone-bearing calix peripheral to the stone.
	- ideal tract is through upper pole calyx.
	- ideal tract is through middle pole or lower upper pole.
	- ideal tract is directly through diverticulum.
	- : Ureteropelvic junction obstruction (UPJO) and upper ureteral stricture
		- ideal tract is through middle pole or upper pole calix (Lojanapiwat, 2006).

#### **3.2.6.2 Upper pole access for renal access**

The upper pole of the kidney aligned medially and posterior to the lower pole, making the upper pole a shorter and easier access route. The upper-pole approach provides a straight tract along the long axis of the kidney and ensures the ability to reach most of the collecting system while providing easier manipulation of rigid instrument. The operative techniques of upper pole access need coordination with the anesthetists for controlling breathing for prevention of intercostals vessel and pulmonary complication. (Lojanapiwat & Prasopsuk, 2006) (Table 3, 4)


Table 3. Indication for the upper pole access.


Table 4. Technique of upper pole access.

Modern Surgical Treatments of Urinary Tract Obstruction 275

In special situations, such as an impacted stone in the collecting system, the manipulation often requires small angled-tip catheters and hydrophilic coated wires. Then the needle is removed, and progressively larger dilators are introduced over the guidewire to dilate the access tract to facilitate the placement of soft nephrostomy tube. The size of tract dilatation depends on the goal of percutaneous access. If the goal is to provide external urinary drainage, serial dilators are inserted over the guidewire to dilate the tract to a sufficient size for the nephrostomy tube. The 8 or 10 Fr nephrostomy tube is introduced over the

The most reliable evidence for the proper placement of the nephrostomy tube can be demonstrated by nephrostogram under fluoroscopic imaging. The guidewire is withdrawn and the nephrostomy tube is secured with skin to prevent dislodging the catheter. The catheter is connected to a urine bag for drainage. (Fig. 17-20) For permanant nephrostomy tube placement, the tract can be further dilated and a regular Foley's catheter can be used.

guidewire and optimal position is monitored by ultrasound or fluoroscopy.

Fig. 17. Ultrasonic probe for guidance the nephrostomy tube placement.

Fig. 18. Dilators over the guidewire.

#### **3.2.6.3 The causes of access failure**

