Percutaneous Endoscopic Cervical Diskectomy

44 Percutaneous Endoscopic Cervical Diskectomy


Gun Choi, Alfonso García, Akarawit Asawasaksakul, and Ketan Deshpande


44.1 Introduction


First described by Robinson and Cloward, anterior cervical diskectomy and fusion has become an established, commonly performed operation for subaxial cervical disk prolapse.1,2 Although anterior cervical diskectomy and fusion (ACDF) still remains the mainstay of the surgical options for cervical disk prolapse, it requires entrance into the spinal canal, with the accompanying risk of complications, such as epidural bleeding, perineural fibrosis, graft-related problems, dysphagia, and hoarseness. Indirect decompression using minimally invasive laminoforaminotomy fails to address the pathology anteriorly. The successful use of percutaneous endoscopic cervical diskectomy (PECD) has been reported by several authors.3,4,5,6 In the long-term outcome reported by Lee and Lee, the reduction of disk height and progression of disk degeneration did not have any effect on clinical symptoms.7 Also, Kim et al stated that cervical curvature did not worsen after posterior PECD.8 These findings proved that PECD can be an excellent alternative for treating various cervical disk problems with meticulous selection of patients.9 Indications for PECD include soft cervical disk prolapse without cervical instability or evidence of central canal or foraminal stenosis. PECD and thermodiskoplasty can effectively treat diskogenic cervical headaches due to soft disk herniation.10 PECD is not advisable above the C3 level because of the broader hypopharynx and carotid artery bifurcation. It is also not recommended for patients with previous anterior surgery, axial neck pain, cervical infection, or tumor. Relative contraindications to PECD include bilateral cervical radiculopathy.11 The advantage of PECD is that it can accomplish both a decompressive surgery and thermal neurotomy/denaturation with the use of radiofrequency (Video 44.1).


44.2 Indications


• Low cervical (C3–C7) soft disk herniations without segmental instability


• Cervicogenic headache


44.3 Contraindications


PECD is not recommended for:


• Patients with previous anterior cervical surgery


• Patients with dominant axial neck pain


• Cervical instability


• Cervical infection or tumor


• High cervical level pathology (above C3)


Relative contraindications are:


• Bilateral cervical radiculopathy


• Calcified disk and/or foraminal stenosis


• Cervical stenosis not related to soft disk herniation


44.4 Technique


44.4.1 Anatomical Considerations


When performing anterior cervical disk puncture, one must take into consideration and give careful attention to the carotid artery, which is located medial to the sternocleidomastoid muscle laterally to the entry point and both the trachea and esophagus medially. The pretracheal fascia is fused on either side with the prevertebral fascia, completing a compartment composed of the larynx, trachea, thyroid, and pharynx-esophagus. When moved together, all of these structures displace as one piece, increasing the safety zone for initial disk puncture. The carotid artery runs medially at the C3–C4 level and more laterally at the C6–C7 level. The safest entry point is between the airway and the pulsating carotid artery.


44.4.2 Anatomical Structures Related to Levels of PECD


C3–C4: Inferior Border of Hyoid Bone

• Between the hyoid bone and the thyroid cartilage.


• There is a narrow safety zone. The hypopharynx is broader, and the carotid artery is bifurcated medially.


• The superior thyroid artery is located in the trajectory of C3–C4 puncture.


• Translation movements of the pretracheal fascia enclosing the thyroid gland may change the course of the superior thyroid artery more horizontally.


C4–C5: Middle of Thyroid Cartilage

• The hypopharynx is placed more medially to the lateral margin of the thyroid cartilage, protecting it from injury.


C5–C6 (Between the Thyroid Cartilage and Cricoid Ring) and C6–C7 (Inferior to Cricoid Ring)

• The safety zone is larger at these levels.


• With correct retraction of the carotid artery and pharynx-esophagus, there are no endangered vital structures.


C7–T1

• Slightly more medial approach is advised to avoid lung apex injury.


44.5 Surgical Technique


44.5.1 Settings for PECD


• Laser settings: Energy of 1 to 1.5 J (Joules), 10 to 15 Hz (pulse/sec)


• Radiofrequency cautery: 35 for ablation and 30 for coagulation


• Irrigation pump: Flow at 100% and pressure of 30 mm Hg


44.5.2 Anesthesia


The patient is under conscious sedation with propofol and remifentanil intravenously via a target-controlled infusion pump (Fig. 44.1). This anesthesia modality is preferred, because it allows intraoperative feedback directly from the patient, which makes the procedure safer by informing the surgeon if neural structures are being stimulated.




44.5.3 Patient Position


• The patient is placed supine on a radiolucent table.


• The neck is slightly extended by placing a towel roll under the neck.


• The head can be stabilized by applying plaster tape across the forehead.


• A plastic tent is placed over the patient’s face to prevent the feeling of suffocation after draping and to facilitate communication during the procedure (Fig. 44.2a,b).


• Neck and shoulder padding is done to keep the cervical spine in slight extension (Fig. 44.3a).


• The shoulders are pulled down and the arms are fixed to the sides of the table with plaster tape for better visualization under fluoroscopic lateral view (Fig. 44.3b).



44.5.4 Procedure


• The level and midline are marked with the help of the C-arm fluoroscope (Fig. 44.4a,b).


• For lower cervical levels, the C-arm may have to be tilted obliquely to avoid the 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. 44.5).


• In foraminal disk herniation, approach from the contralateral side is preferable; for a midline herniation, entry from the right side is preferable for a right-handed surgeon.





• Carotid pulse is palpated with the left hand and the tracheoesophageal complex is gently pushed away while applying soft pressure and alternating movements with the fingertips of either the index and middle fingers or the middle and ring fingers until the anterior portion of the cervical vertebral body is felt. The anatomical relationship of the tracheoesophageal complex makes it possible to retract both the esophagus and trachea as a single structure (Fig. 44.6).


• When displacing the tracheoesophageal complex medially and the carotid sheath laterally, it is very important to maintain 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 the C-arm view, making certain the needle is aimed at the target disk space (Fig. 44.7a,b).


• With the fingers kept in place, a 90-mm 18 G needle is inserted into the interval between the carotid sheath and the tracheoesophageal complex up to the anterior margin of the targeted disk space under fluoroscopic guidance in AP and lateral views (Fig. 44.7c).


• Access to the disk is done between the longus colli muscles. This helps to prevent bleeding and sympathetic chain injury. As a reminder, note that the sympathetic chain is located more medially in the lower cervical vertebrae than in the upper cervical vertebrae.


• Diskography (indigo carmine solution mixed with normal saline and contrast media in a 1:2:2 ratio) is done to stain the pathological disk fragment and for confirmation of needle position (Fig. 44.8).


• A guidewire is then passed through the needle and the needle is withdrawn. While the needle is withdrawn, the guidewire should be firmly secured to prevent it from slipping out of the disk space (Fig. 44.9).


• A 5-mm transverse skin incision is made following the skin crease of the neck (Fig. 44.10).


Mar 29, 2020 | Posted by in ORTHOPEDIC | Comments Off on Percutaneous Endoscopic Cervical Diskectomy
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