transfacet screw fixation, spine surgery

1. Trans-facet Screw Fixation
• First described by King in 1948, screw was laterally placed through the ipsilateral
lamina across the articulating joint.
• Overall, the trans-facet screw is directed “down and outward” (ie, caudally and
laterally).
• In contrast to pedicle screws, trans-facet screws do not span the three columns of
the vertebrae. Because pedicle screw systems offer greater purchase of bone,
trans-facet screw fixation is biomechanically inferior. However, the use of trans-
facet screws for posterior per-cutaneous fixation can lead to a reduction of
surgical time and surgical morbidity in select patients.
• Used in conjunction with anterior fixation, trans-facet fixation systems offer
reduced surgical time with comparable strength.

2. • Trans-laminar Screw Fixation ->
• First described by Jacobs et al in 1989, uses screws inserted bilaterally in the
spinous process of the upper vertebra, passing through the contra-lateral
lamina across the facet joints, and ending at the transverse process of the lower
vertebra .
• Trans-laminar screw fixation has been proposed for the treatment of segmental
dysfunction, lumbar spinal stenosis with painful degenerative changes, and
lumbar disk herniation with concomitant degenerative changes, as well as for
segmental revision surgery after disectomy.
• This technique is commonly used to augment anterior column support with
additional posterior fixation via trans-laminar screws.
• The authors concluded that adjunctive trans-laminar facet screw fixation can
enhance stability of the joint, especially when low compressive preloads are
present and the cage alone would be unlikely to provide sufficient stability

3. • Indications for TLFS/ TFS->
(1) Grade I degenerative anterolisthesis / retrolisthesis.
(2) Degenerative lumbar canal stenosis with instability.
(3) Recurrent disc herniation requiring instrumented fusion.
(4) To achieve global fusion after ALIF with minimal instrumentation from the
posterior approach.
(5) Degenerative lumbar segmental instability.
(6) Failed back syndrome requiring instrumented fusion.
• Contraindications for TLFS / TFS->
(1) Prior surgical removal of the spinous process.
(2) Insufficient facets either due to a congenital anomaly or following surgical
excision.
(3) Spondylolisthesis of more than Grade I severity.
(4) Lytic listhesis.
(5) Structural defects of the anterior column.
(6) Severe osteoporosis.

4. • Advantages of TLFS fixation.
(1) Short segment fixation.
(2) Less hard ware. Low cost.
(3) Shorter duration of surgery.
(4) Lower incidence of neurological injury as the screws traverse the lamina
tangential to the spinal canal.
(5) Large surface area is available for graft placement as most of the posterior
arch remains intact.
(6) Adjacent facet joints are not disturbed.
(7) Screw insertion through the lamina minimizes screw contact with muscle
as only the two screw heads project above the level of the bone.
(8) Can be used to achieve global fusion with limited intervention from the
posterior aspect.
(9) Artifacts in the post operative MRI do not obscure the spinal canal.
(10)Comparatively easy learning curve.

5. • Translaminar screw
fixation with screw
placement through the
contralateral lamina
across the facet joint
(A),
• Transfacet screw
fixation through the
ipsilateral lamina across
the facet joint (B),

8. • The starting point of the screw is at the base of the spinous process on the
contra-lateral side. 2A,The starting point of the first screw must be so planned
(either caudal or cranial to the midpoint of the spinous process) to ensure
accurate placement of the second screw from the opposite side. 2B: The drill
and the screw are introduced through a separate stab incision 5-7 cm lateral to
the mid line.