Innovation & Forschung

S. Webb1, R. Prejbeanu2, I.Branea3, , D. V. Poenaru3, D.Vermesan21Florida Spine Institute –Clearwater, SUA21st Department Of Orthopedics And Traumatology Timisoara 3 2nd Department Of Orthopedics And Traumatology Timisoara

Laminectomy surgery

Low back incision

Removal of all or part of the posterior spine

Enlargement of neural foramina to free the offended nerve root

Concurrent fusion to stabilize the spine

Application of bone graft harvested from the hip

Usually involves implantation of hardware to prevent motion until fusion is complete

Procedural complications

Nerve injury associated with decompression due to limited visualization

Incomplete fusion requiring re-intervention

Hip pain associated with bone graft harvesting

Long term issues related to fusion

Changes the normal biomechanics of the spine and accelerates degeneration at adjacent spine segments

Bone regrowth after decompressive laminectomy is accelerated in areas of postoperative spinal instability

Repeat decompression is estimated to be 11% at 6 years

Stabilization with controlled kinematics

Load sharing with anterior and other posterior structures

Symptom relief

Reduction of morbidity of traditional fusion surgery

Tissue sparing (bone)

Role of natural anatomy (patho-anatomy)

Potentially excising pain generators

Familiar (Posterior) surgical technique

Direct decompression

Facet visualization

Ease of revisions

In order to provide a better outcome to the patient in terms of functionality and reduced incidence of complications, “non-fusion” devices should be designed to

Preserve available motion

or preferably

Restore normal motion

but always

Restrict abnormal motion

The advent of non-fusion spinal implants necessitates the accurate characterization of the biomechanics of the posterior elements of the spine, especially the facet.

As artificial disc and nucleus replacements make their way to the market, their biomechanics have been studied and characterized, with a special focus on the effect of such implants on

the biomechanics of adjacent segments

the biomechanics the corresponding facet joints.

This has been done in an effort to ensure that post operatively, their function will be clinically successful, and that an additional potential failure mode has not been created at the other (facet) joints

TFAS™ Archus Orthopedics

Modular design approach

Maximizes alignment flexibility

Addresses sizing requirements

Attached to spine via pedicle

Similar to attachment of pedicle screws for fusion hardware

Leverages extensive clinical experience and technical understanding of TJR

Restores stability while maintaining full range of motion

An Introduction to the Technology

TFAS™ is an articulating joint prosthesis intended to restore normal motion and provide stabilization of spinal segments in skeletally mature patients.

It can be used as an adjunct to laminectomy, laminotomy, neural decompression and facetectomy, in lieu of fusion, for the treatment of instabilities or deformities of the lumbar spine including:

Degenerative disease of the facets

Degenerative disease of the facets with instability

Grade I degenerative spondylolisthesis with objective evidence of neurologic impairment

Central or lateral spinal stenosis

Complete versus partial removal of facets

Allows for safer, more comprehensive decompression

Eliminates the possibility of further degeneration and recurrence

Removes a potential source of low back pain

No fusion

Patient gets full range of back motion

Normal spine biomechanics are restored preventing future adjacent segment issues

No bone graft harvest procedure and associated pain

Biomechanics

Stabilize the spinal segment

Preserve segmental biomechanics

Avoid fusion and therefore minimize stress on adjacent levels

IAR in posterior third of VB

Cephalad Arm

Cross Arm

Housing with Hexalobe Set Screw

Caudal Bearing (Cup)

Cephalad Bearing (Ball)

Caudal Stem

(5.75 & 6.5 mm)

Integral Cone Tip End

Caudal Bearing

Cephalad Stem

(5.75 & 6.5 mm)

Clamp Housing with Hexalobe Set Screw

Cross Arm with Cephalad Bearings

Archus Bone Cement

Tecotex® Surface

Bearing Ramp Angles:

115º flexion

115º extension

Stabilizes motion

Motion Limits:

Prevent dislocation

115º

Extension Stop

Flexion Stop

Home Position

Endplate

115º

Strength

Modularity

Wear

Stability

Fixation

Wear Couple

Custom designed coupled motion simulator

Volume of CoCr debris comparable to that reported in literature

Particle size and distribution comparable to state of the art MOM hips

TFAS™ bearing wear = low end of metal-on-metal TJA at 10 million cycles

No neurotoxic/toxic response locally/systemically in vivo

The TFAS™ effectively

stabilizes motion in flexion and lateral bending

restores the motion in extension

limits the motion in axial rotation

TFAS™ restored motion of an unstable FSU (no facets or posterior ligaments) to that of an intact FSU, allowing anatomic range of motion in all degrees of freedom

TFAS™ Kinematic Testing

TFAS™:

Pedicle Fusion System:

Under the same applied loads, TFAS™ experienced lower implant stresses

TFAS™ treated level loads the disc similar to an intact level

Nine patients: 6L4-L5/3 L3-L4 (f. u only 6)

Average age 71.2

dg: lumbar stenosis

Instrumentation time 1-2hr, operation time 4 hr

Posterior approach

Decompression

Resection of inferior articular process

Transpedicular instrumentation (proximal first)

Measurement and probe (always double check)

Ciment

fixation

Female 65 y

Spinal stenosis

TFAS L4-L5

6m FU

Male 74y

Spinal stenosis with spondilolistesis L4-L5 Gr. I

TFAS L4-L5

6 m FU

IDE approved in the U.S.

Recruiting investigative centers

Conducting cadaver training sessions

Enrollment in U.S. is underway – 2 patients

TFAS an strong alternative to fusion in treatment of Lumbar Spinal Stenosis in the near future