Ultrasound Study to Validate the Anterior Cervical Approach to the Longus Colli Muscle Using Electromyography Control Alone

Abstract

Background: One of the main difficulties in the treatment of dystonic anterocollis is the injection of the deep flexor muscles of the neck such as Longus Colli (LCo). The injection of the LCo has been regarded as difficult and potentially dangerous; since we published our anterior median approach, a number of questions about the precision and the safety of our technique have been raised by colleagues. Methods: 7 patients with anterocollis were injected, using our injection technique and when the needle was deemed to be in place, we used the ultrasound probe to determine what the needle had passed through, the depth of the tip of the needle and if the identified muscle was indeed LCo. Results: On the ultrasound section the LCo muscle is between 24 and 28 mm deep in the patients examined in this study. The location of the needle was confirmed by ultrasound and in most cases the needle was placed in the right axis but sometimes not deep enough. The EMG control made it possible to correct the depth in all cases. In most of the injections the needle traversed the thyroid. No acute incident occurred by this route of injection. Injections were performed between 22 and 28 mm deep. Discussion: From this study and based on a review of complications over 9 years experience with injecting LCo under EMG control using an anterior approach, we conclude that this technique is precise, safe and well tolerated. Summary (Highlights): The injection of the Longus Coli muscle for anterocollis has been regarded as difficult and potentially dangerous. This study showed, using ultrasound to determine the needle trajectory, that the anterior approach using EMG control is a precise, safe and well tolerated technique.

Proposed Potential Anatomical Landmarks for Percutaneous Botulinum Toxin Injection in Anterocollis-typed Cervical Dystonic Patient: A Pilot Study Utilizing Thiel-embalmed Human Cadavers

“…It seems that guidance indicates safe and effective BoTX injections into this muscle should be established to reduce potentially harmful incidents. 6,13 LCo is located on the anterior surface of the C1-T3 vertebrae, and it is innervated by the anterior rami of the second (C2) to the sixth (C6) cervical spinal nerves. This muscle can be divided into three anatomic compartments: the superior oblique part, vertical intermediate part, and inferior oblique (the smallest element).…”