Endoscopic Anterior Cervical Discectomy (Disc Preserving)
Keywords: Cervical pain, cervical spondylosis, cervical vertebrae, discectomy, herniated disc, intervertebral disc, intervertebral disc degeneration, neck pain, prolapsed disc
The endoscopic anterior cervical approach is an effective and safe alternative to conventional anterior cervical discectomy (ACDF) with an additional advantage of preservation of most of the natural disc, conservation of motion unit, avoidance of fusion, minimum root handling, and a direct anterior approach to the pathology.,,,,
This video demonstrates a step-by-step procedure for endoscopic anterior cervical discectomy.
The surgery is done under general anesthesia. The patient is placed supine with the neck extended. The surgeon stands on the ipsilateral side. After confirming the level under fluoroscopic guidance, an incision of size approximately 3.0 cm is made medial to the medial border of sternocleidomastoid preferably on the neck crease. The platysma is opened and deep cervical fascia is incised. The trachea and esophagus are retracted medially, and the carotid sheath is retracted laterally. The pathological level is reconfirmed with fluoroscopy. Ipsilateral longus colli is partially excised to expose the lateral part of the desired level if needed. An incision mark over the disc is made, and the endoscopic set is introduced. We used the “Easy Go” (Karl Storz, Tuttlingen, Germany) endoscopic set in the majority of cases.
Using a high-speed drill with 3 mm cutting and diamond burr, a part of the uncinate process below and the uncus of the above body is removed for the lateral disc. Incision through the central part of the disc is made for the central disc. A small part of the normal disc is removed to reach the compressing disc material. Leaving a thin piece of cortical bone protects the vertebral artery with its venous plexus. The sufficient opening to permit two slender instruments is made which can be slightly broadened posteriorly to remove all compressive disc and osteophytes. The drilling is done ventrally until the posterior longitudinal ligament (PLL) is exposed. The PLL is incised with a sharp hook, dissected from the dura, and removed with a 1-mm Kerrison punch. The extruded or subligamentous disc portion, if present, is removed with hooks under direct vision. Herniated central part of the disc and compressed opposite side root can be dealt by rotating the scope. The decompression is confirmed with the appearance of epidural bleeding, good pulsations of the dura, and easy passage of a 90° hook under the vertebral bodies.
Hemostasis is achieved by irrigating warm saline and if required, a piece of thin gel foam. Fusion is not necessary. The closure is done in layers in a standard manner.
Video Link: https://youtu.be/t8WLEv4mdR4
Video timeline with audio transcript:
00:12–00:34: A 30-year-old male patient presented with complaints of radicular pain in the right forearm radiating to the index and middle finger for around 2 months duration. Neck pain also had same duration. On clinical examination, there was a 50% reduction in sensory loss in the C7 dermatome and depressed right triceps jerk.
00:35–00:45: The dynamic X-ray of the cervical spine shows no signs of instability. You can see there is a slight reduction in the C6-C7 disc space. The intervertebral foramen height is well maintained.
00:46–00:54: The preop MRI shows protrusion of the disc at the C6-7 level, which is right centrolateral without signs of myelopathy.
00:55–01:04: Patient is placed in a supine position without traction. The neck is kept in a slightly extended position. Chin being anchored by a leucoplast.
01:05–01:08: C6-C7 space is localized under fluoroscopy.
01:09–01:22: You can see the midline and the medial border of the sternocleidomastoid. The incision of about 3 cm is marked preferably along the skin crease medial to the sternocleidomastoid
01:23–01:35: The surgeon stands on the right side of the patient with a video monitor being placed exactly opposite him. The exposure to prevertebral fascial is exactly similar to any standard anterior approach.
01:36–02:05: A tubular retractor sheath is introduced and gradual serial dilators are used. The final docking is done on the C6-C7 space. The docking is reconfirmed using a C-arm. This is the endoscopic view showing C6-C7 disc space, caudal C7 vertebra, cranial C6 vertebra, and right longus colli, which is to the lateral side.
02:06–02:24: Using an insulated monopolar cautery, a minimum amount of overhanging longus colli is coagulated and C6-7 is further defined. Care is excised not to touch the tip of the tubular sheath with the cautery to prevent collateral damage.
02:25–02:35: The surgeon keeps his elbows at 90° to avoid excess fatigue, and fingers are supported over the sheath.
02:36–03:03: Small amount of disc is removed on the lateral side to preserve a large amount of disc, as this is a disc preserving surgery. A high-speed drill with a 3 mm cutting burr is used. The inferior margin of the superior vertebra and superior margin of the inferior vertebra are drilled to create a small bony window.
03:04–03:11: While doing all this procedure, you can see the surgeon's hands are quite stable and resting in the position, which was described earlier.
03:12–03:44: The drill is held cautiously as if the drill is dancing over the uncinate process to make the underlying disc pop out. Once the disc is visible, a fine curette is introduced first away from the midline and then turning it medially. The visible disc is removed using a pituitary rongeur. Later, 2-mm Kerrison punch is introduced, a visible disc is removed, and then the remnants are removed from the rest of the space.
03:45–04:03: Further removal of the posterior margin of the vertebrae is done by holding the drill and using it in a paintbrush technique either parallel to the thecal sac or away from the thecal sac. Care is taken not to dig the drill at any point.
04:04–04:11: Intermittent saline wash not only makes the operative field clear but also helps in dissipation of the heat.
04:12–04:29: Ideal end-stage drilling should be target-oriented, which is conical in shape with a broad base towards the posterior side, and the space is available for using two instruments at a time.
04:30–04:59: Next the posterior osteophytes are drilled. The thinned out bone is removed using a Kerrison punch. Care is taken to introduce the Kerrison punch first in the disc space, which is either turned upwards or downward to remove the drilled osteophytes in bits and pieces. Sudden dipping of the Kerrison punch is avoided to prevent injury to the dura.
05:00–05:11: It is always better to hold the Kerrison handle as a power grip and the other hand of the surgeon as a pen grip to guide the Kerrison shaft.
05:12–05:51: After this, a sharp hook is used to deliver the remaining disc fragment. Care is used to move the sharp hook parallel to the thecal sac. You can see a large fragment being delivered. A longitudinally running posterior longitudinal ligament is visible. A small pore is made in the PLL using a sharp hook. Complete removal of the remaining PLL is done by piecemeal till the white glistening dura is visible.
06:03–06:14: After this, a blunt right-angled probe is used to check for the subligamentous extrusion of the disc first from the lateral side and then on the medial side.
06:15–06:25: At the end of surgery the pulsatile dura should be visible. Postoperatively this patient was free from his radicular pain.
06:27–06:47: This is the postop computed tomography (CT), which shows a small entry point of the C7 disc space anteriorly, which is precisely on the target. By drilling, it is small on the interior space, and conical and which broadens as it goes posterior.
Authors have performed this procedure in 240 patients. The age ranged from 21–67 years. The average postoperative reduction in disc height, operating time, and blood loss were 1.1 mm ± 0.3, 110 ± 12 min, and 30 ± 5 mL, respectively. The average preoperative visual analog scale score for arm pain and Nurick grading was 7.6 ± 0.5 and 2.7 ± 0.2, which improved to 1.9 ± 0.2 and 0.82 ± 0.1, respectively. Two patients had transient C5 root paresis, which improved within 3 months. There was no permanent complication or any mortality.
Using maximum magnification, the telescoping tip should be kept farthest from the operative site, and suction kept inside the field to avoid the lens soiling during drilling. The endoscopic tube should be kept as vertical as possible; the surrounding tissue tends to enter it when it is angled which obscures proper visualization. While drilling, the hands should be supported on the sheath of the endoscopic set to improve precision. The use of power grip alone needs to be avoided because of poor precision compared to pen type of precision grip, especially when working near the cord. When the power grip is essential, the surgeon can add precision grip at the distal part of the instrument with the other hand to improve precision. Bleeding can be controlled with head-end elevation, cold saline lavage, use of gelatin sponge with or without prothrombin, and if required Floseal.
The transdiscal endoscopic anterior discectomy, without fusion, has been found safe and effective. Compared to the conventional ACDF, the complication rate and revisions were comparable. Though the microscopic anterior cervical discectomy may be considered a gold standard, the endoscopic approach may be considered an alternative with the added advantages of minimal invasiveness, better visualization, and avoidance of fusion. There is no need for fusion as the majority of the disc is preserved, as shown in the video. Mechanical instability is an absolute contraindication to this approach. Our results in 240 patients showed that the technique is safe and effective. Similar results were shown in other series.
Endoscopic technique is an effective and safe alternative to ACDF after attaining the learning curve.
This video was not been published previously in any other journal earlier.
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Conflicts of interest
There are no conflicts of interest.