The level and midline are marked with the help of C-arm fluoroscope (Fig. 12.4A and B). For lower cervical levels, the C-arm may have to be tilted obliquely to avoid shoulder girdles. The anterior cervical skin is prepared and draped. Lidocaine (1%) is infiltrated into the skin and subcutaneous tissue at the entry point (Fig. 12.5). In the case of a foraminal disk herniation, approach from contralateral side is preferred. For a midline herniation, an entry point from the right side is preferred for a right-handed surgeon. The carotid pulse is palpated with the left hand and tracheoesophageal complex is gently pushed away while applying soft pressure and alternating movements with the fingertips of either index and middle fingers or middle and ring fingers, until the anterior portion of the cervical vertebral body is felt. The anatomic relationship of tracheoesophageal complex makes it possible to retract both esophagus and trachea as a single structure (Fig. 12.6). When displacing the tracheoesophageal complex medially and carotid sheath laterally, it is important to maintain this hand position while holding the guide needle between the third and fourth fingers before insertion. Confirmation of needle position and minor adjustments are made with the aid of a C-arm fluoroscope, ensuring that
the needle is aimed at the target disk space (Fig. 12.7A and B). Keeping the fingers in place, a 90 mm 18G needle is inserted into the interval between the carotid sheath and the tracheoesophageal complex to the anterior margin of the targeted disk space under fluoroscopic guidance in anteroposterior (AP) and lateral views (Fig. 12.7C). The disk is accessed between the longus coli muscles. This helps to prevent bleeding or injury to the sympathetic chain. Remember that the sympathetic chain is located more medially in the lower cervical vertebrae in comparison to the upper cervical vertebrae. Discography (Indigo carmine solution mixed with normal saline and contrast media in 1:2:2 ratio) is done to stain the pathologic disk fragment and for confirmation of needle position (Fig. 12.8A to C). A guide wire is then passed through the needle and the needle is withdrawn. When withdrawing the needle, the guide wire should be firmly secured to prevent it from slipping out of the disk space (Fig. 12.9). A 5-mm skin incision is then made in a transverse direction following the skin creases of the neck (Fig. 12.10). Serial dilators are passed over the guide wire starting from 1 mm. This maneuver is done with the right hand while the left hand is firmly guarding the carotid artery laterally and one finger is displacing the tracheoesophageal complex medially. C-arm verification of the correct positioning of guide wire is mandatory while inserting the dilators. A second dilator is lightly tapped until its tip is in close proximity and in line with the posterior vertebral wall on lateral C-arm view (Fig. 12.11A to F).