Basilar Invagination Associated With Atlantoaxial Dislocation Clinical Trial
Posterior compression distraction reduction technique （PCDR） in the treatment of Basilar invagination associated with atlantoaxial dislocation
Basilar invagination (BI) refers to the skull base into the direction of cervical spine,
mainly to the odontoid process into the foramen magnum is a major change of congenital
cranial vertebral junction malformation. Different from trauma or inflammatory lesions,
there exists not only in horizontal but also vertical direction dislocation between atlas
and axis，At present there is no satisfactory and widely accepted operation method. At
present, the main treatment strategy is adopt skull traction to patients preoperative or
intraoperative and make vertebra X-ray observation. If the skull traction restored the
atlanto-axial dislocation, This case belongs to restorable atlanto-axial dislocation. If the
skull traction cannot restore the dislocation, that is non-restorable atlanto-axial
dislocation. For the restorable type, posterior occipital cervical internal fixation and
fusion should be performed. For the non restorable cases, the main theories is that various
ligaments and scars is formed between the anterior arch of atlas and the odontoid process
lead to the causes of the longitudinal traction, so transoral anterior atlanto-axial joint
lysis is needed first, and then adopt posterior occipital-cervical internal fixation and
interbody fusion after the atlanto-axial dislocation is restored. Because the anterior
trans-oral atlanto-axial joint lysis has weakness of difficult and high risk, it has limit
the popularization of the treatment of atlanto-axial dislocation. Currently only a few
several spinal surgery centers have the ability to carry out. Another problem of this
treatment strategy is that the function of posterior operation confined to
occipital-cervical fixation in situ but not considered the try to adopt the posterior open
reduction, this is mainly due to the current clinical application of occipital cervical
posterior fixation system be lack of the pressure reduction effect.
Abumi proposed posterior operation incision, atlanto-axial restore intraoperative technique
in 1999, and designed the first compression screw that has a restore function in the
operation. But it hasn't been widely used because of the intraoperative reposition and
internal fixation instrument design is not reasonable and the restore technique has a lot of
deficiencies In 2006 Wangchao reported another posterior atlanto-axial dislocation reduction
technology. The restore direction of this technology is more reasonable than Abumi's, but
the occipital titanium plate adopted in this kind of restore technique is still evolved the
occipital-cervical internal fixation system designed by Abumi, just have the mechanical
properties of restore level atlanto-axial dislocation. but for atlanto-axial dislocation
caused by the Basilar invagination is still need to adopt restore by skull traction. And in
many cases also need to perform anterior transoral atlanto-axial joint lysis in order to
achieve expected reduction effect.
Wangchao adopt the same occipital-cervical internal fixation system as Abumi technique to
perform pressure reduction of atlanto-axial dislocation. This technology is more reasonable
in the pressing direction. Using the occipital-cervical internal fixation system was same as
Abumi technique it doesn't own the function of Distraction reduction. Therefore for the
vertical dislocation of atlanto-axial Still need to restore by skull traction, some patients
need the anterior transoral atlanto-axial joint lysis to restore by traction.
In 2010 the members of the project group reported the atlanto-axial dislocation restore by
simple posterior screw internal fixation technique and has achieved effect. The investigator
can restore vertical dislocation between the atlanto-axial effectively by applying
distraction force between occipital screws and axis pedicle screws. For those Basilar
Invagination (BI) complicated with Atlanto-axial dislocation(AAD), the rate of Atlanto-axial
reduction100% reached 65%. But due to the use of internal fixation system is ordinary
occipital cervical internal fixation system （Summit system，DePuy Co) lacking of the function
pressure reduction, therefore the effect of level reduction of atlanto-axial dislocation is
poor. In some cases it induct atlanto-axial joint rearward opening angle increases, odontoid
falling backwards aggregately, the medulla spinal cord angle narrowed further.Furthermore,
Part of the reasons why atlanto occipital complex malformation patients failed to achieve
100% reduction is that atlanto-axial lateral is deformities seriously, utual locking, it is
difficulty to restore by this technology.
The technology divided intraoperative reduction process into two operating. First of all,
restore the level of dislocation between atlanto-axial through pressure, and then restore
the vertical dislocation between atlanto-axial through distraction. The investigator
designed the compression occipital plate (COP) owned functions both compression and
distraction reduction in order to make it convenient in intraoperative technical operation.
The investigation report of Patent Bureau indicated that the design of this type of titanium
plate is creative and novel.
The clinical application of this technique has achieved initial success in the treatment of
basilar invagination complicated with atlanto-axial dislocation patients. This technology so
far is the most reasonable posterior reduction technology in the treatment of basilar
invagination complicated with atlanto-axial dislocation mechanics mechanism.
Although the compression distraction reduction technology has obvious advantages analyzed
from the mechanical properties of angle application of pressurized occipital titanium plate,
but if the application of this technology can be safely effective cure basilar invagination
and atlanto-axial dislocation patients, improve neurological function, still need further
prospective clinical study.
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| Status | Clinical Trial | Phase | |
|---|---|---|---|
| Recruiting |
NCT02463630 -
Posterior Compression Distraction Reduction （CDR）Technique in the Treatment of BI-AAD
|
Phase 3 |