Shoulder Traction as a Possible Risk Factor for C5 Palsy in Anterior Cervical Surgery: A Cadaveric Study

Area of Science:

• Neurosurgery
• Anatomy
• Biomechanics

Background:

• Postoperative C5 palsy (PC5P) is a known complication of posterior cervical approaches.
• Risk factors for PC5P, such as "cord shift," are well-documented.
• The potential role of shoulder traction in anterior cervical surgery as a PC5P risk factor remains under-investigated.

Purpose of the Study:

• To evaluate the degree of nerve root stretching when shoulder traction is applied.
• To assess the impact of varying traction forces on the C5 and C6 nerve roots.
• To identify potential risk factors associated with shoulder traction-induced nerve root stretch.

Main Methods:

• Eight human cadavers were utilized for the study.
• Shoulder traction forces ranging from 2 to 20 kg were applied to the shoulder joint.
• The elongation of the C5 nerve root was measured in the extra-foraminal zone, with additional measurements for the C6 nerve root and superior trunk of the brachial plexus.

Main Results:

• The C5 nerve root exhibited an average stretch of 1.94 mm at 8 kg and 5.03 mm at 20 kg of traction.
• Individual C5 nerve root elongations at 8 kg and 20 kg ranged from 0.75/4.38 mm to 2.13/5.31 mm.
• The C6 nerve root showed elongations of 1.88 mm at 8 kg and 5.44 mm at 20 kg.

Conclusions:

• Shoulder traction during anterior cervical surgery may be a contributing risk factor for postoperative C5 palsy.
• Patients with pre-existing foraminal or central spinal stenosis may face an elevated risk.
• Surgeons should consider this risk, implement precautions, and provide thorough patient explanations.