Subaxial facet dislocation reduction techniques

Closed Reduction Techniques

Authors:

Walton et al. (1893): First reported closed reduction by manipulation.
Crutchfield et al. (1933): Introduced tongs for in-line traction-reduction.

Methods:

Basic Procedure: Gradually apply traction, followed by anterior rotation and lateral flexion away from the side of the dislocated facets to disengage them.
Once disengaged, rotation is carried out in the opposite direction, and the neck is extended upon hearing or feeling a "click".
Traction Weights: Vary among reports.

Reindl et al. suggested starting with 5 kg + 2.5 kg per level of injury below C1, increasing by 2.5 kg every 30 minutes to a maximum of 50% estimated body weight.
Tumialán et al. applied an initial 9.1 kg, increasing by 4.5 kg per hour, reaching 27.2 kg.
Miao et al. reported initial 5 kg, with most reductions completed by 15 kg.

Controversy

Under GA:

Controversial in its use.

Pre-reduction MRI:

Debated whether it's necessary.
Some suggest it's crucial to assess for disc disruption/herniation and spinal cord compression

Rizzolo et al. found 42% disc disruption
Darsaut et al. 88% incidence

Others argue it may delay reduction and decompression, which is critical for neurological outcome, and transportation of unstable patients to MRI poses risks.

Pros:

Historically but proven technique for many cervical facet dislocations.
Safe technique

esp if done awake

Cons:

Can be almost impossible to reduce with this technique if the dislocation is old or if facets are severely locked

Using excessive weights that could lead to neurological injury

Requires close neurological monitoring, and imaging to monitor progress is not always feasible.

Generally recommended for conscious and cooperative patients; severely injured or uncooperative patients may need rapid open surgical reduction.

Not always successful, requiring open reduction in some cases.
Even after successful closed reduction, open surgery with stabilization is often necessary due to inherent cervical spine instability from soft tissue injury.

Outcomes

Success rates range from 30% to 100%
Risk of neurological deterioration

Mahale et al. 4.3% deterioration;
Hadley et al. 1 permanent root deficit from traction;
Grant et al. 1 patient deteriorated 6 hours post-reduction).

Anterior-Only Approach Techniques

General Pros:

Anterior approach is surgically less traumatic due to blunt interplane dissections,
Has lower infection rate (0.1% to 1.6% compared to 16% for posterior approach),
Has direct access to the injured intervertebral disc for decompression via discectomy.

General Cons:

Can be challenging for delayed dislocations or severe vertebral fractures/osteoporosis, as distraction forces may cause iatrogenic spinal cord injury or vertebral body fracture
Anterior plate fixation in flexion injuries has a notable radiographic failure rate (13% reported by Johnson et al.).

May require additional posterior fixation for severe posterior column injury.
Anterior pedicle screw and plate fixation, while an option for stability, requires a highly experienced surgical team.

Cloward's "Cervical Dislocation Reducer"

de Oliveira's Interbody Disc Spreaders

Author: de Oliveira (1979).
Methods: Surgical treatment through an anterior approach using interbody disc spreaders to reduce interlocking facets.
Referring to Figure: Fig. 3 (illustrates the use of an intervertebral distractor).
Pros: All 12 patients (100%) were successfully reduced with no neurological deterioration. Reduction of interlocking facets can be achieved easily and safely with correct technical details.
Cons: Not explicitly stated.

Ordonez et al.'s Caspar Pins and Curette/Disc Interspace Spreader

Author: Ordonez et al. (2000).

Methods:

After standard anterior discectomy, vertebral body posts (Caspar or Disc spreaders) are placed at a 10°-20° divergent angle to apply a bending moment during distraction.
Once facets are disengaged, dorsally directed pressure is applied to the dislocated cranial vertebrae.

Pros:

The ventral surgical procedure is safe and effective.
MRI is effective for identifying traumatic disc herniations.

Cons:

Outcomes

90% reduction rate in 10 patients.
Some patients (2 out of 10) had residual alignment issues (unilateral perched or dorsal elements splayed).

Modified Caspar Retractor System with Laminar Spreader/Periosteal Detacher

Authors: Reindl et al. (2006) and Ren et al. (2020).

Methods:

If Ordonez technique is insufficient, a laminar spreader (Reindl) or a periosteal detacher (Ren) is inserted into the disc space. /2
Distraction and cephalad rotation of the instrument are then used to unlock the dislocated facets.

Pros:

Outcome

Reindl et al.

75% reduction rate using Caspar pins and a laminar spreader.
25% anterior open reductions failed, requiring posterior surgery, and one patient experienced neurological deterioration during surgery (though recovered).

Ren et al. achieved a 97.1% reduction rate using Caspar pins and a periosteal detacher, concluding the anterior reduction and fusion is effective and safe.

Cons:

Facet dislocation associated with a pedicle fracture may indicate an initial posterior approach.

Du et al.'s Trial-Model Device as a Lever

Author: Du et al. (2014).

Methods:

Performed under spinal cord evoked potential monitoring.
After discectomy and opening the posterior longitudinal ligament, skull traction is maintained until facet alignment is achieved.
Insert the trial-model device after removal of the in-
volved intervertebral disc.
The weight of traction is increased gradually utile the inferior articular process of dislocated vertebrae was just right on top of the superior process of inferior vertebrae.
Poke the inferior vertebrae to unlock the facet dislocation (reduction by leverage.

Outcome:

100% successful reduction in 17 patients.

Zhang's Anterior Pedicle Distraction Reduction

Author: Zhang (2017).

Indication

For cases where vertebral distractor reduction failed.

Methods:

After anterior discectomy, a pedicle distractor (anterior screw tapper) is implanted along the pedicle axis under fluoroscopy.
A trial model is placed as a fulcrum in the intervertebral space, and the distractor directly applies force to the locked facet.
The spreader is pressed down to pry and disengage the facet, followed by pushing the upper vertebrae caudally for reduction.

Outcome:

100% successful reduction in 4 patients who failed conventional techniques.
No neurological deterioration occurred.

Li et al.'s Anterior Cervical Distraction and Screw Elevating-Pulling Reduction

Author: Li et al. (2017)

Methods:

Insert Caspar pins into the superior and inferior vertebral body.
Under intraoperative fluoroscopic monitoring, gradually distract until the facet joints are cleared.
An anterior cervical titanium plate with a length equal to the distance of distraction by the retractor was placed between 2 Caspar pins, and then implant a suitable length of half-thread cancellous bone screw into the middle vertebral body.
Pull the dislocated vertebrae until it was pressed against the titanium plate.

Outcome:

100% successful reduction in 86 patients (42 treated with this technique) with no neurological deterioration.

Cons:

Conventional anterior approach techniques still had disadvantages, such as the need for precise instrument insertion depth and preventing secondary spinal cord injury from instantaneous springing during reduction.

Kanna et al.'s Modified Anterior Reduction with Separate Instruments ("Joy Sticks")

Author: Kanna et al. (2017).

Methods:

Placement of Caspar pins parallel to the endplates in the sagittal plane and perpendicular to the vertebral body in the axial plane.

The Caspar pin distracters are used for distraction, and an interbody spreader is placed between the vertebral bodies to sustain the distraction.

The Caspar distracter is removed leaving the Caspar pins free in the vertebral body.

The interbody spreader act as a distracter while the Caspar pins are used as “joy sticks.”

The pins are moved to provide a transverse rotation or flexion-extension moment to reduce.

Outcome

100% successful reduction in 39 patients with no neurological deterioration.

It is a safe and effective technique for sub-axial cervical facet dislocation (AO type C injuries).

One patient experienced a partial loss of reduction.

Cons:

Using a single instrument for traction and reduction could be dangerous to neural and vascular structures.

Liu and Zhang's Kyphotic Paramedian Distraction with Caspar Pins and Anterior Facetectomy

Authors: Liu and Zhang (2019).

Methods:

Kyphotic Paramedian Distraction:

Direction of the upper pin place at the dislocation side in the axial plane.
Placing Caspar pins at approximately a 10° to 20° with respect to each other in the sagittal plane.
After anterior discectomy, gradual distraction (arrow) under fluoroscopy until disengagement of locked facets was observed on the lateral view. Application of dorsal and rotational force to the rostral vertebra to achieve reduction.

Anterior Facetectomy (if distraction fails):

Facet locking remains after the kyphotic paramedian distraction.
An anteromedial foraminotomy by resection of the posterior foraminal area of uncovertebral joint. Resection of the edge of the dislocated superior facet after the nerve root was retracted cephalad in the neuroforamina.
Application of the dorsal and rotational force (arrow) to the rostral vertebra to achieve reduction.

Outcomes:

100% successful reduction rate in 63 patients (52 with distraction, 11 with facetectomy) with no neurological deterioration.
The procedure boasts a 100% reduction rate, even for patients with severe vertebral fractures, articular process fractures, and delayed management of bilateral facet dislocation.

Cons:

Facet locking may persist after kyphotic paramedian distraction, necessitating anterior facetectomy.

Posterior-Only Approach Techniques

General:

Facilitates easier reduction by directly releasing locked facets and allows for removal of dorsal spinal cord compression. Posterior pedicle screw fixation offers superior biomechanical stability, promoting long-term bone graft fusion.
This approach is particularly beneficial for patients with posterior column damage, offering higher stability than anterior approaches.
It is recommended for cases of old facet dislocation, severe vertebral fractures, osteoporosis, ankylosing spondylitis, or comminuted facet joint fractures where anterior-only techniques might fail.
Cons:

Cannot address herniated intervertebral discs or other soft tissue compression on the ventral side of the spinal cord before reduction.
There is a risk of iatrogenic surgical complications if compressive materials enter the spinal canal and compress the spinal cord during posterior reduction.
For patients with intervertebral disc destruction, there's a risk of poor fusion and fixation failure due to insufficient anterior-middle column support, potentially requiring a subsequent anterior procedure.

Instrument assisted manipulation

Periosteal Elevator Assisted Manipulation

Author: Alexander et al. (1967).
Methods:

Under skeletal traction, a small sharp periosteal elevator (Adson) is inserted between the facets.
It is gradually turned and twisted to widen the separation and break adhesions.
If adhesions are persistent, the ventral margin or even the entire superior facet may be removed to complete the reduction.

Pros: The authors suggest that earlier reduction after injury generally makes the process easier.
Cons: Not explicitly detailed, but subsequent developments suggest limitations.

Spinal Curette Assisted Manipulation

Authors: Bunyaratavej et al. (2011) and Park et al. (2015).

Methods:

A curette is placed between the locked facets and the curette
is turned so that the cup side docks with the inferior edge of the facet.
The curette is gently pull caudally so that the inferior
facet is levered up and over the superior facet.

The curette is then turned so its cup side docks with the inferior edge of the rostral facet, and the handle is gently pulled caudally to lever the rostral facet up and over the caudal facet. Park et al. used a Kocher clamp and curette.

Application of dorsal and rotational force to the rostral vertebra to achieve reduction.

Outcome

Bunyaratavej et al. reported 100% reduction in 5 patients where closed reduction failed, with no neurological deterioration, deeming the technique safe and effective.
Park et al. achieved 100% reduction in 21 patients (including those with traumatic disc herniations), with all patients showing neurological improvement and successful removal of disc fragments.

Cons:

Bunyaratavej et al. warned of the risk of injuring the exiting nerve root and vertebral artery if the curette is placed too deeply.
It is contraindicated in the presence of facet fracture, disk herniation, or bone fragments in the neuroforamina.

Fazl and Pirouzmand's Modified Interlaminar Spreader

Author: Fazl and Pirouzmand (2001).

Methods:

Using a modified interlaminar spreader.

Outcome:

Achieved 100% reduction in 52 patients with no neurological deterioration, offering a feasible and reliable approach to open reduction.

Cons:

Not explicitly stated.

Nakashima et al.'s Bone-Holding Forceps for Posterior Reduction

Author: Nakashima et al. (2010).

Methods:

Gentle axial traction is applied to the injured cervical spine using a Mayfield head holder.
After exposure, bone-holding forceps are used to apply a gradual distraction force between the spinous processes to reduce anterior translation. Once the inferior articular process aligns with the superior process, a dorsal force is pulled to the rostral vertebra to achieve reduction.
If reduction fails, particularly for old subluxations, a high-speed burr may be used to resect the tip of the superior articular process to release locked facets.

Outcome:

Achieved 100% reduction in 40 patients (including those with traumatic disc herniation) with no neurological deterioration.
Neurological improvement was observed in 25% of total cases and 75% of incomplete paralysis cases.

Cons:

Not explicitly stated.

Barrenechea's 1-Stage Posterior Technique

Author: Barrenechea (2014).

For an old cervical subluxation (e.g., 2-month standing C5/6 facet dislocation).

Methods:

Resembling lumbar spondylolisthesis reduction
Under neurophysiologic monitoring, the patient is positioned prone with slight neck extension.
A wide bilateral foraminotomy is performed using a high-speed drill to refracture partially ossified facets.
Lateral mass screws are placed, and a rod is secured.
A rod reducer is then used to bring the screw head back towards the rod, realigning the lateral mass screw heads and reducing the subluxation.

Combined Approach Techniques

General:

Pros

Considered the most definitive operation for maintaining cervical stability after fracture or dislocation.
More highly recommended for bilateral dislocations compared to anterior or posterior fixation/fusion alone.
Combines the advantages of both anterior-only and posterior-only approaches.

Cons

The optimal sequence of combined approaches remains controversial.
The procedure is more complicated than single-approach techniques, demanding a higher physical condition from the patient and carrying a greater risk of postoperative infection.
Multiple changes in patient position during surgery may lead to secondary spinal cord injury.

Liu et al.'s Posterior-Anterior Approach for Old Distractive Flexion Injuries

Author: Liu et al. (2008).

Methods:

Posterior First:

Facetectomy and sufficient soft tissue release for reduction, followed by fixation with spinous process wire and posterior element fusion using morselized autogenous cancellous graft.

Anterior Second:

Subsequent anterior approach surgery for decompression, fusion, and internal fixation.

Outcome

In 9 patients with old distractive flexion injuries,

Neck pain significantly remitted and neurological function improved.
Anatomic reduction was successfully achieved and maintained until fusion in most cases.
One patient experienced partial loss of reduction, though fusion was ultimately achieved.

Shimizu et al.'s Fluoroscopy-Assisted Posterior Percutaneous Reduction (Minimally Invasive)

Author: Shimizu et al. (2019).

Methods:

The reduction instrument and principle are similar to Alexander et al.'s (periosteal elevator) but inserted percutaneously through a small incision above the facet with fluoroscopic assistance.

Reduction is achieved via lever action.

This is followed by anterior cervical discectomy and fusion (ACDF).

Yang et al.'s Posterior Unlocking under Endoscopy followed by Anterior Decompression, Reduction, and Fixation

Author: Yang et al. (2019).

Methods:

Posterior unlocking of facet joints is performed under endoscopy, followed by an anterior approach for decompression, reduction, and fixation.

Pros: In 4 cases of old subaxial cervical facet dislocations, no neurological deterioration or iatrogenic injury occurred. Patients reported improved neck visual analogue scale scores and disability index. It offers an alternative technique for old SCFD cases.

Cons: Limited to 4 cases.

Allred and Sledge's Anterior Bone Grafting before Reduction (Buttress Plate)

Author: Allred and Sledge (2001).

Methods:

Grafting and instrumentation of the anterior cervical spine are performed before reduction, using a tricortical iliac crest bone graft secured with a buttress plate.
This is followed by posterior reduction and fusion.

Outcome:

No neurological deterioration occurred in 4 patients.

Cons: Song et al. later suggested that the buttress plate alone might not provide sufficient safety against graft motion or spinal cord impingement.

Song et al.'s Prefixed Polyetheretherketone (PEEK) Cage and Plate System

Author: Song et al. (2013).

Methods:

A modified technique using a prefixed PEEK cage and plate system for the anterior stage to improve upon the limitations of buttress plates regarding graft motion and spinal cord impingement.
This is part of an anterior-posterior procedure.

Pros: In a case report of irreducible bilateral cervical facet fracture-dislocation with a prolapsed disc, no instability or complications were observed. It addresses the potential drawbacks of buttress plates by providing better fixation.

Cons: Limited to a single case report.

Wang et al.'s New Anterior-Posterior Surgical Approach (Peek frame cage & buttress plate with posterior reduction)

Author: Wang et al. (2014).

Methods:

After anterior discectomy, a PEEK frame cage (containing autologous iliac bone particles or tricalcium phosphate) is inserted and fixed anteriorly with an appropriate PEEK composite buttress plate using two screws.
The anterior wound is closed, and the patient is positioned prone for posterior manipulation.
Reduction is achieved by gentle distraction of involved spinous processes with tooth forceps, prying locked facets with a reset handle, and progressive neck extension.
Finally, posterior internal fixation is performed using mass or pedicle screws.

Outcome:

All 8 patients were successfully treated with no neurological deterioration or instrument failure.

Feng et al.'s Anterior Decompression and Nonstructural Bone Grafting followed by Posterior Reduction and Fixation

Author: Feng et al. (2012).

Methods:

The patient is placed supine for an anterior approach, involving discectomy and divergent placement of Caspar distraction pins to distract the disc space by 1-3 mm.
An absorbable gelatin sponge is placed in the posterior disc space, followed by morselized cancellous bone grafts in the anterior disc space.
The anterior wound is closed, and the patient is turned prone for posterior reduction and internal fixation with lateral mass screws.

Outcomes:

All 21 patients (with traumatic disc herniation) were successfully reduced, with no instrument failure or complications.

Ding et al.'s Anterior Release and Nonstructural Bone Grafting and Posterior Fixation

Author: Ding et al. (2017).

Methods:

An anterior approach involves discectomy and morselized bone grafting, followed by posterior reduction and fusion.
This technique is similar to Feng et al.'s procedure.

Outcome

All 9 patients with old lower cervical dislocations were successfully reduced, with no neurological deterioration or procedure-related complications.

Miao et al.'s Immediate Reduction under General Anesthesia and Combined Anterior and Posterior Fusion

Author: Miao et al. (2018).

Methods:

This approach involves closed reduction under general anesthesia, followed by immediate combined anterior and posterior fusion.

Outcome:

All 24 patients with distraction-flexion injury were successfully treated with no major complications.