Minimally invasive transforaminal lumbar interbody fusion

1. Mohamed Mohi Eldin
Professor of Neurosurgery
Cairo University
Mini open TLIF

2. First described
The paraspinal sacrospinalis muscle-splitting approach to the lumbar spine.
With decreased bleeding
Providing a more direct approach to the transverse processes and pedicles
Wiltse Approach (1968)

3. TLIF
Provides anterior column support for fusion and instrumentation with only
one approach via a transforaminal route
Offers excellent exposure with
minimal risk because of
minimal retraction on the nerve roots
and dural sac

4. Standard Open TLIF
adversely affect short- and long-term patient outcomes
large skin incisions, extensive muscle dissection
long operation time, significant blood loss
postoperative paraspinal muscle denervation

5. Target surgery
One of the main goals of MISS is
to do an efficient
“target surgery”
with a minimum of iatrogenic trauma

6. Mini-TLIF as a Gateway Technique

7. Mini-TLIF
First described by Foley et al. (2003)
via local muscle splitting at the area of facetectomy and entry point of pedicle
screws insertion significantly diminishes iatrogenic soft-tissue & facet injury.

8. Mini-TLIF
Because minimal retraction on the nerve roots and dural sac,
and lower risk of neurological deficit
It also
offers advantages in revision patients
in whom scar tissue
makes open techniques difficult.

9. Indications of Mini open TLIF
Discogenic pain due to decreased disc height
Micro or macro instability.
Recurrent disc herniation.

10. Advantages
Without compromising the effectiveness of the conventional fusion
Minimal PO pain & hospital stay
Unilateral exposure
Less soft tissue damage
Minimal blood loss
Better cosmetic results

11. Disadvantages
Technically demanding
New
Old
When
?
False negative
Indifferent result Positive result
Increased operative time, Steep learning curve

12. Parameters of learning curve
• Length of operative time
• Amount of bleeding
Intraoperative
Vac drain
• Starting day of ambulation
• Transfusion incidence
• Occurrence of complications

13. Technique
Decompression + Fixation + Fusion

14. Procedure
include
Decompression thru tubular retractor
Obliquely inserted TLIF cage fusion
Percutaneous pedicle screw fixation

15. Planning the skin incision

16. Make the skin incision
In the parasagittal plane of the pedicles under fluoroscopy.
Typically, two fingerbreadths off of the midline
.
L4-5 fusion (black)
L5-S1 fusion (blue)
Four pedicles of interest
L4-5 Mini-TLIF.
Incision size is 3 cm

17. Pitfall 1
Lumbar fascia is incised in the plane of the skin incision
Pitfall:
Do not attempt to find and follow the plane between multifidus and longissimus.
This would direct the exposure Too laterally.

18. Blunt separation of longitudinal
muscle fibers

19. Freeing of the attached
muscle fibers

20. Prepare for retractor
before inserting the mini-open retractor system
Cut the musculotendinous
attachments to
the underlying bone

21. Retractor blades required
Use the smallest diameter tubular retractor blades required to provide the
necessary exposure

22. Facetectomy
Identify the pars before starting the facetectomy
(high-speed drill/small osteotome)

23. Facetectomy
Care should be taken when drilling the pars,
as it overlies the exiting nerve root

24. Pedicle-to-pedicle exposure
Care should be taken when resecting the lateral edge of the lamina
from a lateral approach
A pedicle-to-pedicle exposure is obtained, exposing the traversing and
exiting nerve roots and the disc space

25. Pedicle screws
First the pedicles are only cannulated;
(screw heads might impede access to the disc space)

26. Pedicle screws
We do not place the pedicle screws until
the interbody space is prepared and the TLIF cage is inserted

27. Disc Space Preparation
Disc incised and removed with shavers, rongeurs, and curettes
Cartilagenous end plates removed without injuring the bony end plates.
Interbody trials serially dilate the disc space.

28. Nerve roots
Ligamentum flavum is removed piecemeal to expose nerve roots
Lordotic cage is then selected with a secure fit,
with the autograft packed in it.
Nerve roots are visualized during CAGE insertion.
Additional autograft is also packed within the disc space

29. For narrow disc spaces
Consider first inserting pedicle screws on the contralateral side
and distracting them before inserting the TLIF implant.

30. For spondylolisthesis
Consider first inserting
pedicle screws on the
contralateral side and
distracting them before
inserting the TLIF implant

31. Pitfall 2
If a K-wire is to be used after a facetectomy
keep in mind that the nerve roots are exposed and vulnerable.
Initial placement of the K-wire should be visually guided

32. Spinal canal decompression
by angling tubular retractor medially onto hemilamina

33. Bilateral decompression
achieved by using 2 sets of expandable tubular retractors
in a mini-open fashion
If further lordosis is needed: perform (Smith-Peterson osteotomy -SPO)-
bilateral laminotomies with complete facetectomies).

34. Two levels fusion mini-TLIF
The skin incisions extend to cover entry points of
uppermost and lowermost pedicle screws indicated by fluoroscopy
The lengths of skin incisions are 7 centimeters
The fusion procedure is not different to one segment fusion

35. Cement Augmentation
for Osteoporosis

36. MI versus mini-open approach
Selection is dependent on the need for
unilateral versus bilateral decompression
For bilateral decompression = bilateral mini-open approach.
For unilateral decompression = minimally invasive technique with
percutaneous pedicle screws

37. Durotomy - Pitfall 3
CSF leaks can be difficult to repair.
However, if encountered, close the dural defect primarily by
 A small needle driver and dural suture.
 A small piece of dural substitute and fibrin glue (seal)
 If necessary, a lumbar drain might be placed.
One advantage of the smaller
opening is decreased space
for potential
pseudomeningocele formation

38. RESULTS

42. Image Documented fusion
Absence of halo around the screws
presence of continuous trabecular
bone bridge
between the upper and lower body
on x-ray films

43. Fusion
6 month postoperative CT scan
Fusion after 23rd month

44. More Results
Reduction in intensity of postoperative pain,
with much better cosmetic results

45. Tubular or
speculum like
retractor
small lateral
skin incisions
The Keys of Success
Successful Mini-TLIFSuccessful Mini-TLIF
The microsurgical skill
of the surgeon
Microscope,
C- arm, and
radiolucent
table
lamina-facet
complex,
transverse P.
clearly identified

46. Problems you may face
1. Radiolucent operative tables
2. Magnification and good illumination
3. A special retractor to work comfortably
4. If the axis line is more than 11 cm (process difficult)
5. Hard ware is expensive in relative to the conventional
one
6. Radiation exposure

47. Summary and Conclusions
Although this technique can be safely applied in patients
requiring decompression and fusion
It is challenging and requires a steep learning curve
to operate in the limited surgical field
with microsurgical technique