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Authors of section

Authors

Carlo Bellabarba, Marcelo Gruenberg, Cumhur Oner

Executive Editor

Luiz Vialle

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Anterior plating

1. Preliminary remarks

Anterior fixation is a useful technique for anterior decompression and reconstruction of the anterior column.

Direct decompression from disk or bone material can be performed directly without mobilization of the neurological structures.

Visualization of the dura allows direct confirmation of complete decompression.

Nerve roots are better identified from a posterior approach, but experienced surgeons can also perform an anterior foraminotomy.
Anterior plating for cervical trauma enables decompression, reconstruction, and direct dura visualization.

Preoperative evaluation of potential anatomic variations in the course of the vertebral artery is mandatory. Unidentified anatomical variations may increase the risk of compromising the artery during decompression.

Anterior plating for cervical trauma; artery anatomy must be evaluated to avoid surgical complications.

Surgical complications

More details on surgical complications can be found here.

2. Approach and preparation

With the patient placed supine, one of the two following approaches may be used depending on the exposure needed:

Anterior plating for cervical trauma with patient positioned supine for surgical access and stabilization.

3. Indications for anterior decompression

Indications for decompression during anterior reconstruction includes:

  • The presence of a traumatic disc herniation causing neurologic injury (discectomy alone)
  • The need to remove a portion or entire vertebral body followed by reconstruction for stability, or for relief of symptomatic neural compression
  • Kyphotic angulation with ventral compression.

Corpectomy is performed when the anterior column is severely compromised and/or to remove bone material from the spinal canal. In this procedure diskectomies above and below the fractured vertebra are performed first, allowing visualization of the upper and lower limits of the spinal canal.

Visualization

The procedure should be performed with adequate light and magnification; either loupes or a microscope.

4. Discectomy technique

Prior to performing the discectomy, the level is confirmed with intraoperative fluoroscopy.

The following landmarks are identified:

  • Midline
  • Unciform process

The midline will dictate the AP orientation of the discectomy.

The unciform processes dictate the lateral borders of the discectomy, establishing the safe area from the artery. This will leave a 3 mm safe zone to the normal anatomy of the vertebral artery.

Anterior plating for cervical trauma; discectomy guided by midline and unciform to protect vertebral artery.

A small (nr 15) blade is used to open the annulus from uncinate to uncinate as close as possible to the endplates.

Pearls: To help stop a slipping blade, a Frasier tip suction is held in place in the direction the blade is cutting.

To prevent accidental durotomy and spinal cord transection, the annulotomy should not go deeper than 11 mm. The sharp edge of the nr 15 blade is 11 mm and can be used as a depth gauge.

Anterior plating for cervical trauma; annulotomy depth limited to 11 mm to avoid spinal cord injury.

The discectomy continues using Pituitary rongeur forceps to remove the anulus and small curettes to scrape the endplates.

Anterior plating for cervical trauma; discectomy uses rongeur and curettes to clear disc and endplates.

The use of a distractor or an intervertebral distractor will facilitate the removal of the posterior half of the disk and visualize the posterior longitudinal ligament.

The normal height of the area should be reconstructed. However, care should be taken not to over distract.

A complete discectomy will allow good visualization of the spinal canal and enhance fusion.

Anterior plating for cervical trauma; distraction aids full discectomy and spinal canal visualization.

Meticulously remove all cartilage from the endplates. Pieces of cartilage may inhibit fusion if present either on the endplates or in the bony material used for the fusion.

Anterior plating for cervical trauma; all cartilage must be removed to ensure proper spinal fusion.

A small probe is used to ensure that no fragments are left in the area behind the vertebra, which is not directly visualized, or in the foramen.

Magnification and correct illumination are essential to make the final decompression.

Anterior plating for cervical trauma; probe checks hidden areas, with magnification aiding decompression.

5. Full corpectomy technique

Corpectomy technique

Prior to performing a full corpectomy, both the superior and inferior discs are removed to define the safe depth of bone resection.

Segmental vessels are identified and ligated in the mid vertebral body, away from the natural foramen. These vessels may already be disrupted due to the trauma.

Anterior plating for cervical trauma; discs removed to guide corpectomy depth, vessels ligated mid-body.

Laterally the corpectomy is limited by the medial border of the unciform process.

The unciform processes dictate the lateral borders of the corpectomy, establishing the safe area from the artery. This will leave a 3 mm safe zone to the normal anatomy of the vertebral artery.

Anterior plating for cervical trauma; corpectomy limited by unciforms to protect vertebral artery zone.

At this point, the fractured portion of the vertebral body (but not the posterior third) is removed using a combination of Leksell rongeurs and osteotomes.

If a cage is used for reconstruction, an instrument producing larger fragments of bone is preferred as it facilitates the filling of the cage.

Anterior plating for cervical trauma; vertebral body fragments removed, larger ones saved for cage filling.

A burr is used to remove the posterior portion of the vertebral body as the spinal canal is approached.

Anterior plating for cervical trauma; burr removes posterior vertebral body near spinal canal safely.

The spinal canal is decompressed by the resection of the posterior wall of the vertebral body.

The posterior cortex should be thinned with the burr to an eggshell. Retropulsed bone fragments can be removed with curettes and thin footplate Kerrison punches.

This is optimally done with a high-speed burr and curettes under loupe or microscopic magnification.

Anterior plating for cervical trauma; spinal canal decompressed by thinning and removing posterior cortex.
Pearl – Protection of the dura: Care should be taken to protect the dura. Epidural venous bleeding can be troublesome at times, so meticulous hemostasis with bipolar cautery, cottonoid patties, and hemostatic adjuncts can be helpful.
Anterior plating for cervical trauma; protect dura, control bleeding with cautery, patties, and hemostatics.

6. Reduction

In type A fractures, spine alignment will be nearly completely restored by the distraction performed during corpectomy.

The normal height of the area should be reconstructed. However, care should be taken not to over distract.

Anterior plating for cervical trauma; distraction restores alignment in type A fractures, avoid overdistraction.

The over distracted hole will be filled with a larger cage or bone graft and stabilized with a plate. But over-distracted facet joints will make this construct unstable leading to implant failure and eventually pseudo arthrosis.

If this is situation is recognized in the postoperative X-ray, this would be a clear indication for additional posterior fixation (360° procedure)

Anterior plating for cervical trauma; overdistraction risks instability, may need posterior fixation.

7. Fusion after full corpectomy

The following two options are available for reconstruction after corpectomy:

  • Tricortical graft and plate
  • Mesh cage and plate

Care should be taken not to over distract the segment as this may compromise the postoperative stability.

Anterior plating for cervical trauma; reconstruction with graft or cage, avoid overdistraction for stability.

Reconstruction using tricortical graft and plate

Tricortical graft is harvested from the iliac crest and inserted into the defect. Great care must be taken to trim the graft so that it shares axial load with the plate.

Allograft may also be used.

After insertion of the graft, the Caspar pins are removed.

Anterior plating for cervical trauma; iliac crest graft inserted, trimmed to share axial load with plate.

When choosing the plate length, care must be taken not to prevent it from damaging the mobile disks above and below.

Anterior plating for cervical trauma; plate length must avoid contact with adjacent mobile discs for safety.

The plate is finally bent to accommodate the patient's lordosis and fixed with two screws in each vertebra.

Anterior plating for cervical trauma; plate bent to match lordosis, fixed with two screws per vertebra.

Reconstruction using Mesh cage and plate

The corpectomy defect is measured using caliper.

Anterior plating for cervical trauma; corpectomy defect measured with caliper for accurate graft sizing.

A mesh cage of the largest possible diameter is cut to a corresponding length.

Anterior plating for cervical trauma; mesh cage cut to proper length for defect reconstruction.

The cage filled with tightly packed bone obtained from the corpectomy.

Anterior plating for cervical trauma; cage filled with tightly packed bone from corpectomy for fusion.

End plate rings should be added in patients with osteoporosis. They are optional in patients with normal bone. These often have variable angulation and can be used to accommodate nonparallel endplates.

Anterior plating for cervical trauma; end plate rings aid stability in osteoporosis, adjust for angled endplates.

The cage is inserted and tapped into its final position under lateral fluoroscopic monitoring.

The Caspar pins are removed.

Anterior plating for cervical trauma; cage tapped into position under fluoroscopy, Caspar pins removed.

When choosing the plate length, care must be taken to prevent it from damaging the mobile disks above and below.

Note: Dynamic plates should be avoided in trauma as their principles often conflict with the goals of stabilization in the unstable spine.

Variable angle plates with locking screws are also an option if thought to be necessary.

Anterior plating for cervical trauma; plate length must protect discs, avoid dynamic plates in instability.

Ideally the plate would extend as little as possible above and below the endplates of the injured level.

Anterior plating for cervical trauma; plate should minimally extend beyond endplates of injured level.

The plate is bent to accommodate the patient’s lordosis and fixed in place with two temporary pins placed in holes diagonally to each other.

The appropriate positioning of the plate is verified in AP and lateral views.

Anterior cervical plate bent for lordosis, fixed with diagonal pins; position checked in AP and lateral views.

Malrotation of the plate is commonly seen on the AP view and can be adjusted by temporarily removing one pin while adjusting the rotation.

Anterior cervical plate malrotated; AP view shows misalignment, corrected by adjusting one pin.

Based on a preoperative measurement of vertebral body depth, screw holes are prepared with the appropriate depth. This is performed under lateral fluoroscopic guidance.

Screw holes prepared to vertebral depth under lateral fluoroscopy for anterior cervical plate fixation.

Screws are then applied but not fully tightened until all screws have been inserted.

Screws inserted for anterior cervical plate; not fully tightened until all are in place.

Final hardware positioning is verified in lateral and AP view.

Final cervical plate position confirmed in AP and lateral views after screw placement.

8. Aftercare

Patients are made to sit up in bed on the first day after surgery.

A collar is commonly used following surgical stabilization to moderate patient activity.

The purpose of a collar is to prevent ranges of motion outside of limits deemed unfavorable for fracture healing. Collar is optional.

Patients with intact neurological status are made to stand and walk on the second day after surgery. Patients can be discharged when medically stable or sent to a rehabilitation center if further care is necessary. This depends on the comfort levels and presence of other associated injuries.

Patients are generally followed with periodical x-rays at 6 weeks, 3 months, 6 months, and 1 year.

Patient sits up on day one post-op; collar optional; walking starts day two; follow-up with x-rays.