Healthcare: Urology Services

Unroofing of Renal Cysts and Renal Biopsy


Minimally Invasive Surgery



Cysts can form in the kidney for many reasons, and most such cysts are benign (non-cancerous). However, in some instances a cyst may become enlarged to the point that it causes pain, obstructs the kidney, or leads to high blood pressure. Cysts may become infected or bleed. Sometimes a cyst that at one time appeared to be benign changes in shape or other features to the extent that malignancy is suspected. In these instances, unroofing of the cyst and subsequent biopsy may be required. In addition certain renal diseases require a biopsy for diagnosis.

Laparoscopy has provided an ideal way to manage these problems. No large incisions are required; direct visualization of the cyst and/or kidney is provided, and tissue is obtained for more detailed evaluation by the pathologist. In addition, an ultrasound probe placed through one of the ports provides a view of the kidney with the highest resolution possible.



The patient must undergo general anesthesia for this procedure. Two to three small cylindrical tubes called trocars are placed in the abdominal cavity. The trocars allow entry of a video-telescope, called a laparoscope, to provide a view of the entire abdominal cavity and kidney. Additional small trocars allow the introduction of instruments necessary to perform surgery. When all the trocars and instruments are in place the surface of the cyst is completely exposed and cystic fluid is drained. The cyst is then cut out and a biopsy specimen taken from the base of the cyst. The fluid from the cyst and the biopsy specimen are sent to the pathologist for analysis. When only a specimen of tissue from the kidney is required, a portion of the kidney is exposed and a biopsy performed. An advantage of this technique is that an ultrasound probe may be placed through the trocar directly onto the kidney to help guide the biopsy.



Investigators have reported success in more than 95 percent of patients undergoing cyst unroofing, and complication rates are low. Operative time averages 90 minutes, and the hospital stay is less than 48 hours in most cases. The requirement for pain medication is minimal and return to work is often within two to three weeks.

Kidney cysts also can be approached through an open incision, but in these cases, pain medication, hospital stay, and time to return to work are all longer. Another method for treating renal cysts and/or performing a renal biopsy is placing a needle through the skin into the cyst and/or kidney using the help of x-rays. In theory, this procedure is less invasive than laparoscopy. However, this technique does not allow direct visualization of the kidney or cyst, does not provide a large sampling of tissue, does not allow for high-resolution ultrasound guidance, and is associated with a relatively high incidence of recurrence when performed for cyst management.