The cervical oblique corpectomy (DC) approach has the advantages of no grafting or instrumentation necessities and theoretically maintains natural neck motions. However, the risk of cervical sympathetic trunk (CST) injury and Homer's syndrome is one of the main difficulties of this demanding surgical approach. The upper necks of 3 adult human cadavers (6 sides) were dissected under a Zeiss surgical microscope. OC was performed in a stepwise manner to simulate the surgical procedure. We specifically studied the technique of the protection of the CST during the cervical OC approach. The superior ganglion of the cervical sympathetic chain is located under the prevertebral fascia over the longus capitis muscle at the level of C3 transverse process, while the CST is situated under the prevertebral fascia over the longus colli muscle. The CST courses obliquely from superolateral to inferomedial. The ganglia and CST are carefully dissected; the fascia of the longus colli muscle is cut medially, preferably in the midline over the vertebrae, and the fascia lifted up. Then, the aponeurotic flap is gently retracted laterally to cover the sympathetic chain safely and secured with a 3/0 suture laterally. Preservation of the CST while performing cervical OC is essential to avoid postoperative Homer's syndrome. The placement of self-retaining retractors, particularly inferiorly, where the sympathetic chain is located more medially, is probably the main cause of its injury. Further studies are needed documenting the incidence of Homer's syndrome in the application of this technique to live patients. (C) 2019 Elsevier Ltd. All rights reserved.