Posterior Endoscopic Cervical Discectomy
Article information
Abstract
Cervical radiculopathy is a prevalent disorder of the cervical spine. With advances in minimally invasive surgery, posterior cervical foraminotomy (PCF) has been conducted using an endoscopic system, demonstrating favorable clinical outcomes. Posterior endoscopic cervical foraminotomy or posterior endoscopic cervical discectomy could reduce blood loss, operating time, and hospital stay compared to conventional open PCF. We performed a full-endoscopic cervical approach employing one portal with integrated working and viewing channels. When conducting foraminotomy and discectomy, we simultaneously applied a partial pediculotomy, partial vertebrotomy approach to minimize neural retraction and ensure sufficient decompression of osseous structures. The authors illustrate the surgical technique of posterior endoscopic cervical foraminotomy with discectomy.
WRITTEN TRANSCRIPT
0:03 Case Presentation
I am presenting a case involving a 60-year-old female patient with intense pain in her left arm. Neurological examination revealed that the radiating pain and numbness in her left arm were confined to the C5 dermatome, with a positive response to the Spurling sign.
0:24 Preoperative MRI and CT
The preoperative magnetic resonance imaging (MRI) and computed tomography (CT) sagittal and axial images revealed a left foraminal disc protrusion between C4 and C5 vertebrae, accompanied by calcification and bony spur. This resulted in compression of the left C5 nerve, which I illustrated through a diagram. The affecting area is highlighted in red, while the foraminal neural canal is depicted in green to represent the compression.
0:52 Anesthesia Technique and Patient Positioning
The patient received general anesthesia and was placed in a prone position with the neck slightly flexed and in a mild reverse Trendelenburg position. The patient was immobilized using a 3-point plaster traction technique applied to the head, shoulder, and back. Additionally, polyurethane foam pads were applied to prevent pressure on the eyes, nose, and mouth.
1:17 Overview of Full-Endoscopic Approach
First, here is a schematic diagram of the posterior endoscopic cervical discectomy (PECD) technique. Using a single portal, it allows for maximum facet preservation while accessing the lesion [1,2]. The endoscope, A 30° viewing angle, with an outer diameter of 7.3 mm and a working channel of 4.7 mm was used. Continuous normal saline irrigation at a pressure of 30 mmHg was applied. Hemostasis and soft tissue dissection were done with the radiofrequency probe. A long, straight, high-speed drill with a 2.5-mm burr is used for bone work. Next are the obturator and working sleeve, along with commonly used instruments such as the Kerrison punch, bent probe, and forceps.
2:08 Intraoperative C-Arm Images for Level Confirmation
Skin marking was done under guidance of anteroposterior and lateral view cervical fluoroscopy. We aimed for the lateral margin of interlaminar space and medial border of facet joint junction (V point) [3].
2:22 Making a Portal
A transverse 8-mm incision was made at the V point. To facilitate the movement of the endoscope, we used Mosquito forceps to split the fascia. Obturator and working sleeve were inserted and docked, tip position was confirmed with fluoroscopy again.
2:40 Soft Tissue Dissection and Identification of V Point
Hemostasis and soft tissue dissection was performed using a radiofrequency probe. V point is defined as junction of confluence of cephalad and caudal laminofacet which has a V shape configuration.
2:57 Bony Decompression With Foraminotomy
The medial aspect of the lateral mass and facet joint was drilled to create a working window. Firstly, resection of the cephalad laminofacet was performed. Typically, 3 to 4 mm in diameter of bone was removed from the lateral inferior aspect of the upper lamina. Then, approximately 3 mm of the medial inferior portion of the upper facet from the laminofacet border (V point) was removed. Approximately 3 to 4 mm was resected from the superomedial corner of the medial aspect of the superior articular facet of the caudal vertebra, near the dorsal aspect of the nerve root, extending toward the proximal portion of the nerve root.
3:49 Exposure of Cervical Nerve Root
After foraminotomy, ligamentum flavum is partially removed to expose the C5 nerve root. I could expose the C5 nerve root.
4:01 Exiting Nerve Root Decompression and Removal of Prolapsed Disc With PPPV
To achieve a safer and more comprehensive exiting nerve root decompression, partial pediculotomy and partial vertebrotomy (PPPV) were required. We shifted the working sleeve to center on the upper medial aspect of the pedicle, and drilled the pedicle 3 to 5 mm deeper than the neural element level to create a subneural working space. Then, we conducted a partial vertebrotomy. The lateral aspect of the corpus of the caudal cervical vertebra was drilled after the pedicle had been drilled. Following drilling, forceps were employed to push the disc material and osteophytes into the subneural space created ventral to the neural elements, which were then retrieved using forceps. The working sleeve was rotated with the open edge facing away from the axilla of the spinal cord and exiting nerve root, retracting it gently medially to expose the disc. Forceps and a Kerrison punch were used to retrieve the prolapsed disc.
5:08 Bleeding Control and Insertion of Drainage Catheter
Radiofrequency was often used to help in hemostasis. Flowable hemostatic agent was also applied. To prevent postoperative hematoma, I inserted a drainage catheter.
5:21 Surgical Record
The total operation time was 65 minutes, with an estimated blood loss of 40 mL.
5:27 Radiological and Clinical Outcome
Pre and postoperative axial MRI and CT scans reveal an enlargement of the foraminal space. Additionally, the sagittal plane CT shows a cone-shaped PPPV. The 3-dimensional CT images provide a more straightforward understanding of the extent of decompression. The clinical outcome also showed significant enhancement. The radicular pain in the left arm decreased from 8 to 2, the Neck Disability Index score improved from 34 to 9, and the MacNab criteria improved from poor to good. The postoperative wound was minimal, and the patient was able to be discharged 2 days after surgery.
6:15 Discussion
Compared to conventional microscopic surgery the characteristics of endoscopy, including an expanded surgical field of view and flexibility in angles, enable safer and thorough decompression [4]. It has been reported that, not only in radiological findings but also in clinical outcomes, the endoscopic approach is not inferior to open surgery [5]. Obviously, it is widely recognized that the small skin incision and preservation of surrounding tissues, including muscles and ligaments, greatly contribute to the patient's recovery [6]. However, there is limitation. Surgeons accustomed to performing traditional microscopic surgery may not be familiar with the full-endoscopic approach, leading to a steep learning curve [7].
7:03 Conclusion
The uniportal PECD technique enables sufficient decompression while being minimally invasive, offering an alternative to conventional surgery.
Notes
Conflict of Interest
HSK, the Editor-in-Chief of the Editorial Board of Journal of Minimally Invasive Spine Surgery & Technique, is the corresponding author of this article. However, he played no role whatsoever in the editorial evaluation of this article or the decision to publish it. Author has no conflict of interest to declare.
Funding/Support
This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Acknowledgments
The Vrew (VoyagerX, Inc.) program was used for video editing and voice-over.
Informed Consent
Informed consent was duly obtained from the patients.