Percutaneous Endoscopic Cervical Diskectomy



Percutaneous Endoscopic Cervical Diskectomy


Gun Choi

Alfonso Garcia

Bhushan Khedkar



REBUTTAL ▪ The Case against MIS Cervical Diskectomy

Alan S. Hilibrand

First described by Robinson and Cloward, anterior cervical diskectomy and fusion (ACDF) has become an established, commonly performed operation for subaxial cervical disk prolapse.1,2 Even though ACDF remains the mainstay of the surgical approach to cervical disk prolapse, it still requires entrance into the spinal canal with accompanying risks such as epidural bleeding, perineural fibrosis, graft-related problems, dysphasia, and hoarseness. Indirect decompression using minimally invasive laminoforaminotomy fails to address the anterior pathology. The successful use of percutaneous endoscopic cervical diskectomy (PECD) has been reported by several authors.3, 4, 5, 6 From the long-term outcome study by Lee JH and Lee SH, the reduction of disk height and progression of disk degeneration did not affect clinical symptoms.7 Also in 2014, Kim et al. stated that cervical curvature did not worsen after posterior PECD.8 These findings suggest that PECD can be a good alternative for treating various cervical disk problems assuming proper selection of patients.9 The indications for PECD are soft cervical disk prolapse without cervical instability and evidence of central canal or foraminal stenosis. PECD and thermodiscoplasty can effectively treat discogenic cervical headaches due to soft disk herniation.10 It is not advisable for approaching the C3-C4 levels and above because of the broader hypopharynx and carotid artery bifurcation. It is also not recommended for patients with previous anterior surgery, axial neck pain, and cervical infection or tumor. Relative contraindications of 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 radio frequency energy.




TECHNIQUE


Anatomic Considerations

When performing anterior cervical disk puncture, one must consider and pay careful attention to the carotid artery, which is localized 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.


Anatomic 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 at this level. The hypopharynx is broader and the carotid artery is bifurcated medially. The superior thyroid artery is located in the trajectory of C3-C4 puncture. Translational movement of the pretracheal fascia enclosing the thyroid gland may change the course of 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 is minimal risk to the vital structures.


C7-T1

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







Figure 12.1 Target-controlled infusion pump.


SURGICAL TECHNIQUE

Settings for PECD include the following:



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


  • Radio frequency cautery: 35 for ablation and 30 for coagulation


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


Step One: Anesthesia

This is performed under conscious sedation using propofol and remifentanil intravenously with target-controlled infusion pump (Fig. 12.1). This is the preferred form of anesthesia since it is ideal for having intraoperative feedback directly from the patient, which makes the procedure safer by informing the surgeon if neural structures are being stimulated.


Step Two: Patient Position

The patient is made to lie supine on radiolucent table. The neck is slightly extended by placing a towel roll under the neck. Head can be stabilized by applying plaster tape across forehead. A plastic tent is placed over the patient’s face in order to prevent the feeling of suffocation after draping and to facilitate intraoperative communication during the procedure (Fig. 12.2A and B). Neck and shoulder padding is done to keep cervical spine in slight extension (Fig. 12.3A). The shoulders are pulled down and the arms are fixed to the sides of the table by using plaster tape for better visualization under fluoroscopic lateral view (Fig. 12.3B).






Figure 12.2 Plastic tent for patient’s comfort. (A) Lateral view. (B) Anesthesiologist’s view.







Figure 12.3 A: Neck and shoulder padding to keep C-spine in slight extension. If patient has a short neck or when approaching C6-C7 level bilateral arm traction is recommended (B). We use adhesive tape.

Oct 7, 2018 | Posted by in RHEUMATOLOGY | Comments Off on Percutaneous Endoscopic Cervical Diskectomy
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