Complications of Patient Positioning



Fig. 9.1
Steep Trendelenburg with lithotomy position



For radical prostatectomy , a modified lithotomy position is used where the head is placed in extreme Trendelenburg to keep the intra-abdominal contents out of the pelvis. The legs are placed in the low lithotomy position with the ankle, knee, hip, and contralateral shoulder in alignment. The weight of the leg should rest on the heel rather than the back of the knee to avoid popliteal artery occlusion, or, secondarily, weight should rest on the lateral surface of the lower leg to avoid peroneal nerve injury [5].

The arms are tucked into the patient’s sides with foam pads, and the palms should be supported and pronated. Arm board use is avoided, except in obese patients.



Positioning Complications


Patient positioning during robotic surgery may be associated with rare but serious perioperative complications. The surgical team must have in-depth understanding of the potential complications that may arise from different positioning [6]. Postoperative positioning complications were identified in 13.3% of patients undergoing RARP. Postoperative pain and neuromuscular injuries were observed in more than 10.1% and 5% of patients, respectively. The majority of nerve injuries during robotic procedures were caused by stretching (neuropraxia ), electro-fulguration injury, and dissection injury rather than direct nerve transaction. In a large multicenter review of 2775 procedures, patient positioning represented the most common type of injury resulting from robotic surgery. The most common injuries identified were abdominal wall neuralgia, sensory and motor nerve deficit, rhabdomyolysis, and shoulder and back pain [7].

The modified or full flank position may be associated with various neuromuscular complications, including upper and lower extremity neural stretch injuries such as sciatic nerve injury, paresthesia, numbness, rhabdomyolysis of the thigh, and paraspinous muscle pain. These complications are exacerbated by prolonged operative time, especially when the patient is in direct contact with an unpadded table. In addition, the pressure generated at the skin-to-table surface interface was increased in patients with a body mass index (BMI) greater than 25 kg/m2, independent of gender [8]. Higher skin pressure was also observed with the use of full flank position and elevation of the kidney rest. The peroneal nerve may be injured due to compression of the lower leg against the table, while the obturator nerve may be injured during pelvic lymph node dissection (Fig. 9.2). Overstretching of the brachial plexus typically resulted from extended arm abduction, external rotation, and/or posterior shoulder displacement, either in the supine or flank positions [9]. It has been observed that application of shoulder braces in combination with a steep Trendelenburg position may be associated with brachial plexus injuries [4, 10, 11]. The exaggerated lithotomy position for radical prostatectomy may be associated with a high risk of neuromuscular complications due to prolonged flexion and abduction of the patient’s legs, with increased risk of sciatic nerve stretching.

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Fig. 9.2
(a) Upper limb compartment syndrome caused by incorrect intravenous line placement during robotic radical prostatectomy. (b) The patient underwent an emergency fasciotomy (Images courtesy of Juan Arriaga MD, MHA)

Rhabdomyolysis , defined as muscle injury with consequent myonecrosis and myoglobinuria, results from prolonged muscle compression, prolonged operative time, and increased patient BMI. It develops in the areas of direct pressure between bony structures and the surgical table when local blood pressure is approximately 10–30 mmHg below the diastolic blood pressure, resulting in tissue ischemia. The patient usually presents with muscular pain and a dark brown discoloration of the urine due to myoglobinuria; this can lead to renal impairment in up to one-third of patients with rhabdomyolysis [12]. A high serum level of creatinine kinase (CK) (>5000 U/L) may be detected immediately postoperatively [13]. Shaikh et al. found a direct relation between the degree of injury and the length of tissue exposure, where necrosis of the muscle cells occurred mainly after prolonged ischemia of 4 h (Fig. 9.2) [12].

Abnormal positioning of the lower limb during the lithotomy position may result in lower limb compartment syndrome, which is different from that caused by trauma or direct injury, and presents with extreme postoperative and unusual leg pain. Prolonged compression and edema of the lower limbs increase the pressure inside the muscle fascial boundaries with consequent ischemia. Increases in normal intracapillary pressure or decreases in capillary perfusion pressure can compromise blood flow, leading to ischemia and edema. Additional ischemic damage, neuropathy, and rhabdomyolysis may result from reperfusion injury, which induces a cascade of signaling pathways. Symptoms of compartment syndrome can worsen dramatically within a short period and can include severe localized pain on passive stretch of the involved muscles. Neuralgia and/or paresthesia along the dermatomes of the nerves crossing through the affected muscles may also be detected. As a permanent result, muscle paralysis may occur with the loss of peripheral pulses and atrophic changes of the skin.

Elevation and abduction of the lower limbs may injure the superficial and deep branches of the peroneal nerve and the tibial and sural nerves. Clinically, calf swelling and pain may be observed with plantar hypoesthesia and weakness of toe flexion. The use of shorter leg supports may facilitate da Vinci robot docking in the split-leg position, eliminate or reduce the need for hip hyperextension, and prevent or reduce the development of lower extremity neuropathy.

Molloy has recently observed an increase in the intraocular pressure when a patient is in steep Trendelenburg (head down) position [14]. Postoperative corneal abrasions were also observed in 0.1–0.6% of patients, together with postoperative ischemic optic neuropathy [15]. Blindness was detected in less than <0.1% of patients as a devastating complication that has recently been reported after prolonged steep Trendelenburg position [16]. Intraocular pressure is increased in a time-dependent fashion in patients undergoing RARP in a steep Trendelenburg position. Therefore, time-limited procedures appear to have little to no risk from increased intraocular pressure in patients without preexisting ocular disease, and visual function is not significantly changed postoperatively.


Risk Factors for Positioning Complications


Apart from abdominal wall cutaneous neuralgia, which is likely caused by direct surgical trauma at the trocar site, an operative time of greater than 5 h is a risk factor for all neuromuscular injuries [5]. Other well-documented risk factors for positioning injuries include: increased patient BMI (especially with large muscle mass), use of the kidney rest, and male gender [13]. The most important risk factors for rhabdomyolysis include: exaggerated intraoperative lateral position, patients with high muscle mass or morbid obesity, hypovolemia, prolonged operative time, preexisting diabetes, hypertension, or renal insufficiency [13].

Patient positioning in both lithotomy and Trendelenburg positions (with the ankles elevated) represents the main risk factor for development of compartment syndrome, especially with direct calf compression. In addition, prolonged operative time, high BMI, hypovolemia, lower blood pressure, and concomitant peripheral vascular disease may predispose patients to compartmental leg syndrome [17].

The prolonged lithotomy position has been associated with an increased risk of postoperative lower extremity neuropathies [18]. Lower extremity neuropathy was detected in 1.7% of 179 consecutive patients operated on by an experienced robotic surgeon following patient placement in the low lithotomy position [19]. Duration in the dorsal lithotomy position was a potential contributing factor to this injury. The authors expected a higher risk for postoperative lower extremity neuropathies at lower-volume and less experienced centers due to suspected longer durations of the dorsal lithotomy position.

Clinically relevant positioning injuries and rhabdomyolysis can occur in patients who are subjected to prolonged extreme Trendelenburg position during RARP and extended pelvic lymph node dissection; these positions may be prolonged due to the learning curves of early surgeons [3]. Serum CK level immediately increases significantly, peaking at 18 h postoperatively. In patients with a high BMI who are subjected to a very long operation in a Trendelenburg position and have visible position injuries, the authors recommended serum CK measurement at 6 and 18 h postoperatively. Hypervolemic therapy should be started promptly to prevent possible renal injury from rhabdomyolysis if serum CK is >5000 IU/L [3].

Koc et al. reviewed the records of 377 patients who underwent RALP using a split-leg table [20]. Despite the comparable complication rates between split-leg positioning and those previously reported for lithotomy positioning, the length of time in the former position was the only detected potential risk factor for development of lower extremity neuropathy. In addition, split-leg positioning seems to threaten the femoral nerve from hip hyperextension, a condition which is more severe than common peroneal neuropathies secondary to extended lithotomy positioning [20]. Surgeon’s experience can decrease the incidence of most of these complications. Mills et al. reported an incidence of 6.6% positioning injuries from 334 operations; including hand and foot numbness, radial and median nerve palsy, and hip adduction and flexion weakness [21]. This incidence rate is likely higher than anticipated due to the author’s increased awareness of injury, as they claimed. Most of these injuries (59.1%) are resolved within 1 month, while 18.2% resolved between 1 and 6 months, and 22.7% persisted beyond 6 months. Prolonged operative time, in-room time, and American Society of Anesthesiologists class were significantly associated with these positioning injuries [21].


Prevention of Positioning Complications


Positioning problems can be prevented by careful planning and thorough perioperative assessment of all patients undergoing robotic surgery. The surgical team should assess patient positioning at regular intervals throughout the surgical procedure as well as postoperatively, especially in prolonged procedures and/or when extreme positioning is used. As the length of robotic procedures may extend up to 6 h, frequent and careful attention to patient positioning is necessary. The longer the operative time, the higher are the risk factors for all neuromuscular injuries. Careful and appropriate patient positioning before robotic surgery is the cornerstone to avoid or minimize neuromuscular injuries. The surgical team should be aware of the potential dangers of different surgical positions. Moreover, adequate padding for extremity pressure points and appropriate table cushioning can help reduce the risk of pressure-induced complications.

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Jan 26, 2018 | Posted by in UROLOGY | Comments Off on Complications of Patient Positioning
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