A lithotomy is a type of surgical procedure where the removal of stones, or calculi, is carried out. The term lithotomy is generally used to refer to the extraction of kidney stones, but stones may also be removed from other parts of the body, such as the gall bladder. Open lithotomy is rare these days and involves invasive surgery where an incision is made. There is also a type of lithotomy using keyhole surgery techniques, known as percutaneous nephrolithotomy, or PCNL. The study of the kidneys and the diseases that affect them is known as nephrology.
It is not known exactly why kidney stones arise, but the chances of getting one are thought to rise if dehydration occurs, causing an increase in urine concentration. This means that hot environments, failure to drink enough fluids, and increased sweating can all be risk factors. Stones vary in size and shape, and a small stone may pass out of the body without any symptoms, but larger stones may become lodged in the kidney or lower down the urinary tract, causing colicky pain, blood in the urine and sometimes infection. In some of these cases, a lithotomy will be required to remove the stone.
The preferred, least invasive method of dealing with kidney stones involves using shock waves to break stones into tiny pieces that can then easily pass out in the urine. This is called extracorporeal shock wave lithotripsy, or ESWL. Sometimes it is not possible to use this technique because of the size, consistency or position of the stone, and a type of lithotomy may be used instead.
Percutaneous nephrolithotomy is a lithotomy technique where, under general anesthesia, a small incision is made in the skin and, using X-ray technology to ensure it is positioned correctly, a needle is inserted into the kidney. A guide wire is then passed through the needle, and a tube can be threaded along the wire, forming a ready-made channel leading to the kidney and the stone. What is called a nephroscope, a long thin telescope with numerous miniature tools attached, can then be introduced into the kidney along the channel. Stones may be removed whole, using the forceps on the nephroscope, and placed in an attached basket, or they may be broken up using ultrasound or laser energy.
In a few cases, where newer methods are not possible, for example with a very large or awkwardly shaped stone, the traditional open lithotomy procedure may be used. An incision is made in the back, to gain access to the kidney, and the stone is removed. A disadvantage of the open operation is that patients take longer to recover compared with more recent techniques.