Surgical management of urolithiasis in patients with limb contractures presents a unique challenge, as a dysmorphic body habitus may limit optimal access to the bladder or upper urinary tract from either a retrograde or antegrade approach. The anatomic complexity of these cases is further compounded by the high-risk nature of surgery due to comorbidities, adverse social situations, and limited access to care in these patients.¹ As such, meticulous surgical planning is essential to ensure adequate stone clearance while minimizing complications.

Preoperative evaluation and planning are the keys to successful stone surgery in patients with a challenging body habitus. In-person visits are encouraged to allow for direct physical examination and discussion with the patient and their caregiver. A thorough physical examination should evaluate the extent of limb contractures and other musculoskeletal deformities to determine the optimal position that allows access to the kidneys, ureters, and bladder and will maximize stone clearance with the least morbidity. Furthermore, endoscopy of a urinary diversion may be considered in patients with prior lower urinary tract reconstruction to determine whether retrograde access to the ureter is feasible.

For patients with moderate-sized renal or ureteral stones in whom ureteroscopy is the preferred surgical treatment modality, the dorsal lithotomy position is typically the preferred position, as it allows the use of both flexible and rigid instrumentation. This position is best accomplished by placing the legs in stirrups, with the weight on the heels, minimizing pressure on the calves. Most stirrups provide enough range of motion to accommodate mild contractures of the hips, knees, and ankles. Alternatively, candy-cane stirrups may provide adequate lower limb separation and create a working space. If this is not possible or optimal, retrograde access via the supine position with a flexible cystoscope to obtain guidewire access for ureteroscopy is often feasible.

Access to the distal ureter is best accomplished with a semirigid ureteroscope. If positioning precludes that, flexible ureteroscopy, or even antegrade ureteroscopy, may be necessary. In some cases, severe limb contractures may preclude adequate access to the urethra in both men and women or may not allow fluoroscopic imaging of the kidneys and ureters because of interference by the legs (Figure 1). In such cases, particularly in women, prone split-leg positioning using spreader bars and lowering the individual spreader bars as necessary to achieve up to a 90° angle with the horizontal bed can provide surprisingly good access to the urethra for flexible endoscopy (Figure 2). Each leg can be adjusted individually to accommodate differential contractures.

For large and/or complex stones for which percutaneous nephrolithotomy is the optimal surgical modality, patient positioning is generally based on the experience and comfort of the surgeon. No position—flank, supine, or prone—has been shown to be superior to the others.² However, in patients with limb contractures, body habitus and anesthesia considerations may demand one position over another. If neither the prone or supine position can be easily achieved, or if adequate ventilation is precluded in either position, a modified flank position may provide access to the flank and the urethra while allowing for optimal ventilation. Although fluoroscopic-guided access may be a bit disorienting in this position, ultrasound-guided access is less unfamiliar.

Performing percutaneous nephrolithotomy in the modified flank position is appealing due to its versatility. Patients are placed in a lateral decubitus position, similar to that used for robotic-assisted nephrectomy. Familiarity with this positioning is helpful, as the process of positioning the patient can be streamlined by the operating room staff. Extra padding is used to protect pressure points. The ipsilateral arm is tucked against the chest. Malleable support, such as gel rolls, bolsters, or bean bags, are used to maintain the modified flank position at 45°. It is important that the patient be positioned at the edge of the bed to allow sufficient space around the access site to allow for unobstructed instrument movement. Likewise, it is critical to align the iliac crest with the break in the surgical table, as flexion of the table can open up the retroperitoneal space and improve access to the kidney. Furthermore, all-around adhesive strapping at the level of the torso/chest and lower limbs is recommended in the event the table needs to be tilted to improve ergonomics and/or renal access during the procedure.

Upper extremity contractures can also be challenging. Although in the prone position, we typically place the upper extremities with flexion at the elbow and the upper arm bent less than 90° from the shoulder, contractures may preclude that precise positioning. Tucking the arm alongside the body may be possible in some patients in which the arm cannot flex. However, in those for whom the arm is contracted in the flexed position at the elbow or is partially flexed across the chest, removing the cushion from the arm board or suspending the arm with towels and foam to a position lower than or even below the bed may allow the arms to remain flexed but out of the way.

It is evident from this discussion that the key to the successful management of these patients is a versatile operating room table with multiple points of flexion to accommodate the angulation of contracted extremities. Likewise, understanding the limitations of a patient’s extremities is essential. In some cases where the patient will be positioned supine or in dorsal lithotomy, awake positioning allows the patient to vocalize discomfort with any particular position and avoids prolonged unfavorable positions during anesthesia.

In conclusion, a careful preoperative physical examination and thorough discussion with the patient and caregiver regarding the limitations of extremity movement and willingness to spend the time and effort to improvise during positioning to adjust each extremity for maximum comfort individually are key to safe and successful stone surgery in the contracted patient.