The lithotomy position is a common posture used during various medical procedures and examinations, particularly those involving the pelvic and perineal regions. It is a variant of the supine position where the patient lies face-up, but the legs are elevated and supported. The name itself is derived from the ancient surgical procedure known as lithotomy, which involved the removal of bladder stones through the perineum. This posture provides medical professionals with optimal access and visibility to the lower abdomen, genitalia, and rectum. Understanding the mechanics of the position and the safety measures taken to prevent complications is important for anyone undergoing a procedure in this manner.
Describing the Position
The lithotomy position begins with the patient lying flat on their back, which is the standard supine position. The lower body is then adjusted so the hips are flexed, typically to about 90 degrees, and the legs are separated or abducted. The knees are also bent, often between 70 and 90 degrees, with the patient’s feet or lower legs secured in specialized supports.
Leg elevation and separation are achieved using specialized stirrups, which can be the older “candy cane” style or the more common modern “boot-style” holders. The boot-style stirrups are preferred because they distribute pressure over the calf and foot, reducing the risk of localized pressure points. Proper setup involves aligning the ball joint of the stirrup with the patient’s hip joint (greater trochanter) to ensure natural movement.
A fundamental safety protocol during positioning is the simultaneous movement of both legs by two medical staff members. Moving the legs together and symmetrically prevents uneven pressure distribution on the hips and avoids torsion or twisting of the lumbar spine, which could lead to injury. The stirrups are adjusted to ensure the patient’s toe, knee, and the opposite shoulder are in alignment, a concept known as “toe-knee-opposite shoulder” or TKO, which helps maintain neutral rotation and prevents stretching of nerves.
Medical Applications
The common requirement for using the lithotomy position is the need for an unobstructed view and working space around the perineum, pelvis, and lower urinary tract. The position is routinely employed across several medical specialties.
Obstetrics and Gynecology
In Obstetrics and Gynecology, the position is frequently used for procedures like vaginal delivery, as it provides medical teams with clear access to the birth canal. Gynecological surgeries such as hysterectomies, dilation and curettage (D&C), and complex laparoscopic procedures often require this positioning to facilitate the surgical approach.
Urology and Colorectal Surgery
The position is foundational in Urology, enabling procedures that involve the bladder, urethra, and prostate. It is used during cystoscopy, which is a visual examination of the bladder, and for urethral surgeries. Colorectal and proctological surgeons rely on the lithotomy position for access to the anus and rectum, performing procedures like hemorrhoidectomies or surgeries to remove rectal tumors. The slight elevation of the lower body can also be adjusted, creating variations like high or low lithotomy, depending on the specific anatomical exposure required.
Preventing Complications
Despite its utility, the lithotomy position carries risks, especially when used for extended periods, necessitating strict safety protocols. One of the most common concerns is nerve injury, primarily affecting the common peroneal nerve, which runs close to the head of the fibula near the knee. Compression of this nerve against the stirrup or other hard surfaces can lead to “foot drop,” where the patient loses the ability to lift the front part of the foot.
To prevent this, meticulous padding is used on all contact points, and specialized boot-style stirrups are used to offload pressure from the fibular head. Another nerve at risk is the sciatic nerve, which can be stretched if the hips are excessively flexed or the knees are hyperextended. Clinicians monitor the degree of hip flexion, generally keeping it at or below 90 degrees, and avoid extreme external rotation of the hips to minimize stretching forces.
Prolonged use of the position can also impede blood flow, increasing the risk of lower-extremity compartment syndrome, a serious condition involving swelling and pressure within the muscle compartments of the calf. This risk is heightened with procedures lasting longer than two to four hours. Medical teams actively monitor the duration of the positioning and ensure the legs are not elevated above the heart for too long, which can impair tissue perfusion.
Furthermore, the position induces significant hemodynamic changes. Elevating the legs causes a temporary shift of blood volume from the legs back toward the patient’s core, an effect sometimes called “autotransfusion,” which can increase blood pressure and cardiac output. When the legs are returned to the supine position at the end of the procedure, this effect reverses, potentially leading to a sudden drop in blood pressure. Medical staff must lower the legs slowly and simultaneously while monitoring the patient’s blood pressure to mitigate this circulatory instability.