Approach Considerations
A native renal biopsy is typically performed percutaneously through the patient’s back. Other possible approaches are the transjugular kidney biopsy and laparoscopic/open kidney biopsy. For kidney transplant, the graft biopsy is percutaneous and ultrasound guided.
Renal Biopsy
Percutaneous renal biopsy
The percutaneous renal biopsy (PRB) is the standard of care. It is most commonly performed by radiologists and nephrologists. [17]
Adequate tissue is obtained in 95-99% of PRBs, with a typical yield of about 10-20 glomeruli on average, depending on the type of disease, when using 14- and 16-gauge needles.
The patient is placed in the prone position, and the biopsy is typically taken from the lower pole of the kidney if there are no specific locations of interest. In order to localize this portion of the kidney, the biopsy is typically performed under ultrasound guidance. [18]
The biopsy needle is guided using ultrasound to ensure visualization of the needle as it pierces the kidney parenchyma. The size of the needle varies based on physician preference. Needle sizes may vary from 14-18 gauge. Care is taken not to enter the collecting system (as it would result in hematuria) or to go near the renal hilum (to prevent injury to the vessels). An illustration of ultrasound-guided percutaneous renal biopsy is depicted below.
A study by Kriegshauser et al found that operator experience, taking more than 1 specimen, and the use of the cortical tangential approach significantly improved the pathologic material obtained during native renal biopsies. [19]
Ultrasound-guided percutaneous renal biopsy to obtain kidney tissue for diagnosis.
In obese patients and in patients with complex kidney anatomy (eg, horseshoe kidney), renal biopsy can be performed with computed tomography (CT) guidance (see image below). CT scanning can also be used for renal biopsy whenever ultrasound cannot identify or visualize the kidney or the needle biopsy.
If no imaging is used to guide the biopsy, the patient may be asked to take several deep breaths to ensure proper needle placement before obtaining the biopsy.
Transjugular kidney biopsy
Initially performed in the 1990s, the transjugular kidney biopsy is most commonly performed for patients requiring a simultaneous liver/kidney biopsy. Some case series showed no difference in the diagnostic yield or the complication rate compared with PRB. Potential complications are contrast-induced nephropathy as well as capsular perforation that could require coil embolization. [20]
Surgical biopsy
Laparoscopic kidney biopsy, performed by urologists, can be the best approach in cases of morbidly obese patients, failed attempts at PRB, severe coagulopathy, a solitary kidney, or very complex anatomy. The major advantages are direct visualization and a biopsy of the kidney with good hemostatic control of the biopsy site. The biopsy material is usually abundant and sufficient to make the diagnosis of the underlying condition. [21]
Perioperative renal biopsy
In some cases, a urologist may obtain a piece of renal tissue to determine whether it is benign or malignant or to determine whether the margins of resection are negative. For instance, a urologist performing a partial nephrectomy may take a renal biopsy at the surgical bed to ensure that no tumor is left behind before continuing with the renorrhaphy. This can be approached in the same manner as the partial nephrectomy—robotic, purely laparoscopic, or the traditional open approach.
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Perinephric hematoma after a renal biopsy.
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Ultrasound-guided percutaneous renal biopsy to obtain kidney tissue for diagnosis.
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CT-guided biopsy of a renal mass.
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Renal biopsy specimen shows focal segmental glomerulosclerosis on histopathologic examination.
