Percutaneous nephrostomy

Percutaneous nephrostomy is a technique in which percutaneous access to the kidney is achieved under radiological guidance. The access is then often maintained with the use of an indwelling catheter.

Indications

• urinary tract obstruction 
• urinary diversion (ureteric injury, urine leak)
• access for percutaneous procedures e.g. stone treatment, ureteric stenting 

Contraindications

Absolute contraindications

• usually none

Relative contraindications

• coagulopathy, uncooperative patient, severe respiratory disease

Procedure

Pre-procedure evaluation

• review all available imaging to confirm the indication for the procedure. It also helps to assess renal anatomy and establish safe access route to the kidney. 
• check full blood count and coagulation profile to assess the risk of haemorrhage
• obtain informed consent for the procedure
• obtain good peripheral IV access 
• administer broad-spectrum IV antibiotics 1-4 hours prior to the procedure, if needed. Septic patients are often already on parenteral antibiotics.

Positioning / room setup

The procedure is performed with the patient in prone, prone oblique or lateral position, depending on clinical circumstances and patient comfort. Regular monitoring of the vital signs by a suitably trained staff member is recommended during the procedure. Clean skin with antiseptic solution and drape to maintain sterility for the procedure.

Equipment

• ultrasound machine
• local anaesthesia typically with 1% lidocaine
• 18 gauge puncture needle, an alternative would be to use micropuncture set with a 21 or 22 gauge needle.
• 0.38 stiff guidewire (an 0.018 guidewire is also used with a micropuncture set)
• water-soluble contrast media
• dilators ranging from 7-9 French
• pigtail drain (typically 8 French)

 Medications

• 1% or 2% lidocaine (for local infiltration)
• Prophylactic antibiotics - typically a 3rd generation cephalosporin. Selected patients - its use is not routine.³
• Analgesia - not routinely used, but can aid in cooperation in selected patients. Pethidine or fentynl are the usual choices.
• Sedation - a short acting benzodiazepine may be used in selected patients.

Technique

Two common techniques exist. The choice of technique depends on both operator and patient factors. One method utlilizes a 2 or 3 part puncture needle and the other a micro-puncture kit,

Using aseptic technique and following infiltration of local anaesthetic agent, the calyx (usually posterior calyx at the mid or lower pole) is punctured with an 18 gauge, two-part needle under ultrasound guidance. In the presence of renal tract obstruction, urine drains freely on removal of the stylet from the needle. A small volume of water-soluble contrast material can be injected to confirm correct needle position using fluoroscopy. A 0.035 guidewire is used to exchange the needle for a dilator and typically an 8 French pigtail drain is placed within the renal pelvis over the guidewire. On occasion a 6F or 12F catheter may be used, on an individual case basis. A urine sample can be sent off to the laboratory for microbiological studies. The catheter is left to drain freely. 

Postprocedural care

Bed rest (typically 2-4 hours) with regular monitoring vital signs, provision of adequate analgesia are routinely indicated in the first few hours following the procedure. Fluid balance is regularly monitored, particularly in cases of urinary tract obstruction. Indwelling nephrostomy catheters are usually exchanged every three months.⁴  

It is essentially normal for the urine to be partly blood stained for the first 48-72 hours.⁵

The patient should take great care with the nephrostomy tube, to avoid mal-positioning, despite the internal pigtail of the locked drain, skin anchoring stitch and adhesive plaster. Slippage is non-uncommon, but if alerted to medical staff early nephrostomy salvage can be performed without re-puncture.

Complications 

• bleeding
• pneumothorax
• bowel injury and peritonitis
• urine leak
• catheter displacement