Positioning & Nerve Injury
Positioning is a shared surgical, anesthesia and nursing responsibility. Neuropathy, pressure injury, compartment syndrome and ocular injury can occur despite precautions; neither a particular stirrup nor a checklist guarantees prevention. Choose the least extreme position that provides adequate access, and reassess when the operation or the patient's physiology changes.[1][2]
See also: Pelvic Neuroanatomy, Anesthesia, Nerve Blocks and ERAS.
General Principles
Before induction, identify restricted joint movement, existing weakness or sensory loss, vascular disease and vulnerable skin. After positioning, confirm limb alignment, padding, accessible IV lines and airway, and protection from retractors or equipment. Recheck after table changes, docking and any suspected movement; agree on periodic checks appropriate to duration and risk. ASA does not prescribe a universal two-hour inspection interval.[1]
Transfers should preserve spinal alignment and avoid traction on the airway, limbs, catheters and drains. Test a planned steep tilt before draping. Use pressure-distributing supports and dry linens; excessively tight padding or restraints can themselves cause injury.[1][2]
Supine
For tucked arms, keep the forearms neutral, palms toward the thighs, with protected elbows and fingers. For arms on padded armboards, a neutral or supinated forearm may reduce ulnar-groove pressure. Limit arm abduction to 90° when possible in a supine patient; avoid stretching the elbow beyond the patient's comfortable range. This supine recommendation is not a universal prohibition on every prone arm position.[1]
Offload vulnerable heels and other pressure points, and avoid trapping hands against table attachments. Assess both compression and stretch: generous padding does not correct excessive shoulder traction or a tightly tucked arm.
Lithotomy — Low, Standard, and Exaggerated
These labels describe a range of leg positions, not validated universal angle prescriptions. Use only the elevation, flexion and abduction needed for access. Move both legs slowly and together, and ensure symmetric, properly fitted supports. Protect the fibular head and avoid forced hip rotation, excessive hip flexion with an extended knee, and concentrated calf or popliteal pressure.[1][2][3]
Nerve injury may arise from positioning or surgical retraction. Foot drop, quadriceps weakness or new sensory loss requires examination and localization. The duration, severity and persistence of deficits vary; a single pooled “lithotomy neuropathy rate” cannot predict an individual case.
Well-Leg Compartment Syndrome (WLCS)
Elevating the legs, external compression and impaired perfusion can produce compartment syndrome in a previously uninjured leg. The 2019 multidisciplinary pelvic-surgery guideline recommends minimizing elevation and limiting uninterrupted time above heart level to four hours, followed by at least 15 minutes at or below heart level. Plan earlier changes when feasible; four hours is not a guaranteed safe window. If a critical operative step prevents lowering, document the reason and lower as soon as safe.[3]
No leg-support design has been proved to eliminate WLCS. Boots can also compress the calf; avoid tight straps and excessive ankle dorsiflexion. Correctly fitted mechanical VTE prophylaxis still requires a separate risk assessment.[3]
Severe or escalating pain, tense swelling, weakness or sensory change after pelvic surgery warrants urgent assessment for compartment syndrome. Normal pulses do not exclude it. Obtain immediate orthopedic/vascular help; do not delay treatment for DVT imaging or CK results. When diagnosis is uncertain, specialist compartment-pressure assessment may help. Probable WLCS requires emergency decompression; the guideline targets treatment within one hour of diagnosis.[3]
Exaggerated Lithotomy
Limit its use to the portion of the operation requiring that exposure. Do not assume a prone approach is interchangeable with a planned perineal reconstruction. The separate fistula-repair atlas describes approach-specific access; York–Mason is commonly performed prone jackknife, rather than being a standard example of exaggerated lithotomy.
Trendelenburg for Robotic Pelvic Surgery
Use the smallest tilt and shortest exposure compatible with the operation. Prevent sliding without concentrating force on the shoulders; shoulder braces can injure the brachial plexus. A pressure-distributing anti-slide system must fit the patient and table, with the position tested before draping.[1][2]
Head-down tilt and pneumoperitoneum can complicate ventilation and produce facial or airway edema. Coordinate the need for continued tilt with anesthesia, especially during a prolonged case. Extubation depends on airway assessment and recovery, not an automatic cuff-leak test triggered by a fixed number of hours. Maintain an emergency undocking/access plan; see Anesthesia.
Eyes and Postoperative Visual Loss
Protect closed eyelids and keep all devices clear of the globe. Verify that the head has not shifted and that the eyes remain free of pressure. Visual loss has several possible mechanisms; direct globe compression is particularly relevant to retinal arterial occlusion and should not be conflated with every case of ischemic optic neuropathy.[4]
The ASA 2019 visual-loss advisory concerns prone spine surgery. Its definition of a prolonged procedure as more than four hours is not a guideline mandating timed returns to level during robotic GU surgery. Its general attention to blood pressure, blood loss, head position and eye checks is useful, but GU-specific preventive benefit and an optimal check interval are not established by that document. New visual impairment after any operation requires urgent ophthalmological assessment.[4]
Lateral Decubitus — Flank Position
Roll the torso and pelvis together. Support the dependent thorax with a roll caudal to the axilla, rather than placing the roll into the axilla. Support both arms without traction, separate the legs with padding, and protect dependent pressure points. Check the ear, eye, fibular head and lines after turning.[1][2]
Use table flexion and a kidney rest only to the degree required for exposure. Prolonged focal pressure can injure skin, muscle and nerves; pronounced flank pain or swelling after a long case warrants evaluation, rather than being dismissed as an expected incision symptom.
Prone, Prone Jackknife and Split-Leg Positions
Support the chest and pelvis while allowing ventilation and avoiding abdominal compression. Check breasts, genitalia, face and eyes. Arrange the head support so that airway security and the absence of globe pressure can be checked. Reassess after turning or flexing the table.[2][4]
Jackknife adds table flexion for perineal/transanal access. A split-leg setup adds abduction for combined access. Both require reassessment of joint range, pressure points and emergency access; neither removes the risks of a prolonged operation.
Supine Variants for PCNL and Combined Access
Galdakao-modified supine positioning combines flank access with access for retrograde ureteroscopy. The exact setup depends on the table, body habitus, target calyx and planned endoscopy. Confirm leg and arm supports with the operating team before induction.
EAU 2026 supports both prone and supine PCNL, with comparable stone-free outcomes overall. Supine positioning facilitates simultaneous retrograde access, but is not universally safer for every obese or cardiopulmonary-limited patient. Prone positioning remains an established option. Evaluate the planned access tract with appropriate imaging for interposed bowel, pleura and other organs; do not infer a safe puncture from the position's name.[5]
Postoperative Check and Handover
Record the position, supports, prolonged elevation/tilt, changes made and any intraoperative concern. Assess new motor or sensory deficits and skin injury when the patient can participate. Severe pain, rapidly progressive weakness, tense swelling or visual change needs urgent evaluation. Compartment syndrome, neuraxial complications and direct surgical injury must not be mislabeled as routine positional neuropraxia.
References
1. American Society of Anesthesiologists Task Force. “Practice Advisory for the Prevention of Perioperative Peripheral Neuropathies 2018.” Anesthesiology. 2018;128:11–26. doi:10.1097/ALN.0000000000001937.
2. American Urological Association. “Optimizing Outcomes in Urologic Surgery: Intraoperative Considerations.” 2018. White paper, section on preventing falls/positioning injuries. AUA primary document.
3. Gill M, Fligelstone L, Keating J, et al. “Avoiding, Diagnosing and Treating Well Leg Compartment Syndrome After Pelvic Surgery.” Br J Surg. 2019;106:1156–1166. doi:10.1002/bjs.11177.
4. American Society of Anesthesiologists Task Force, North American Neuro-Ophthalmology Society, and Society for Neuroscience in Anesthesiology and Critical Care. “Practice Advisory for Perioperative Visual Loss Associated with Spine Surgery 2019.” Anesthesiology. 2019;130:12–30. doi:10.1097/ALN.0000000000002503.
5. European Association of Urology. “EAU Guidelines on Urolithiasis.” 2026. Section3.4.7, PCNL imaging and positioning. EAU guideline.