The purpose of this study is to establish which of five different maneuvers could bring the best trans-operatory x-ray exposure during anterior cervical surgeries with the higher security

Anterior cervical spine surgery (ACSS) is one of the most common spine surgery performed by neurosurgeons. One of the challenging aspects during ACSS is to achieve a correct visualization and identification of the lower levels specifically below the fifth and sixth cervical vertebras due to the difficulty of penetrating X-ray beams through the shoulders. Several methods such as taping the shoulders throughout the entire case or tying straps around the wrists and pulling them caudally temporally while shooting X-rays have been used trying to improve visualization during surgery. Both of these methods may cause problems such as brachial plexus injury, shoulder dislocations and peripheral nerve injuries.

The feet compression maneuver will be tested in terms of it's efficacy and security, as well as compared with four previous described maneuvers, using intra-operative neurophysiology monitoring (IONM).

50 consecutive patients programmed for elective ACSS that could meet inclusion criteria will be monitored with IONM using transcranial electric motor evoked potentials (tceMEPs), somatosensory evoked potentials (SSEPs) and spontaneous electromyography (EMG) after total endovenous anesthesia. On the operating table, a basal lateral x-ray picture and a first determination of IONM will be performed and used for comparison. Five maneuvers will be sequentially performed: 1) Feet compression, 2) Arm traction, 3) Arm traction plus feet compression combined, 4) Shoulder taping and 5) Shoulder taping plus feet compression.

All five maneuvers will be maintained for 1 min, time during IONM will test for changes in voltage amplitude and duration that potentially could be risky (risky is defined as a change in determinations more than 50% compared to basal determinations). Lateral x-rays will be performed during each maneuver to measure changes in segments visualization and levels exposed.

After all maneuvers are completed, we will proceed as the surgery was scheduled.

Inclusion Criteria:

• Patients with any stable biomechanically cervical pathology (like disk herniations, vertebral tumors, etc.), scheduled for ACSS

Exclusion Criteria:

• Any cervical pathology associated with segmental instability
• History of shoulder, arm, elbow or wrist pathology, including surgery or implants.
• Radiological signs of myelopathy by MRI or clinically detected
• Preoperative identified neurological deficit