This document discusses stand-alone XLIF (extreme lateral interbody fusion) for degenerative disc disease. Key points include: - Stand-alone XLIF is suitable for patients without significant deformity or instability who may benefit from indirect decompression without facet removal. - Benefits include short operative time, minimal blood loss, and shorter hospital stay, making it preferable for elderly patients. - Risks include persistent radiculopathy if indirect decompression is insufficient, cage subsidence especially with 18mm cages, and less biomechanical stability than circumferential fusion. - A study of 31 patients found most had good outcomes with pain and function scores improving at 3 and 6 months. However, 34.

1. Stand Alone XLIF: patients
selection
• Degenerative disc disease without significant sagittal or frontal
deformity, Modic changes 1 or 2 of endplates
• No segmental instability at pre-op imaging, including LS flexion-
extension X-Rays
• Good chance to improve radiculopaty with indirect decompression
(no facet joint arthrodhesis)
• No wide posterior decompression needed (severe narrowing of
spinal canal with claudicatio spinalis)
• No diagnosis of severe osteoporosis

2. Stand alone XLIF: why?
• Short operative time: better for elderly patients with co-morbidities
• Minimal blood loss
• Shorter hospitalization
• Good cost/effectiveness
Stand alone XLIF: handicaps
• Persistent radiculopaty : indirect decompression alone insufficient
• Risk of subsidence of the cage (in particular 18 mm cages)
• Amount of bone growth: biomechanical stability of cage alone
less than circumferential constructs
• Risk of two stages surgery

3. Stand alone XLIF: FU criteria
• Pre-operative clinical assessment completed with ODI
questionnaire, VAS B/VAS L ; pre-operative imaging with LS MRI +
LS lateral and a-p flexion-extension Radiographs
• Clinical evaluation + LS lateral and a-p X-Ray at one month
• ODI/VAS evaluation + LS lateral Flexion-extension X-Ray at three
months
• ODI/VAS evaluation + LS lateral flexion-extension X-Rays at six
months
• In poor grade outcomes, LS MRI was performed

4. Case collection
• October 2011-August 2013: 48 patients treated with XLIF approach: 17
male and 31 females, mean age 62 (range 39-81)
• Of the 48 patients, 37 were treated with stand alone XLIF, 10 with
circumferential approach and one with XLIF + Lateral Plating
• In 3 cases stand alone XLIF + posterior decompression without
instrumentation
• 31 out of 37 patients completed the FU and were enrolled for the study
• 21 patients single level procedure, 10 patients double level procedure
livelli trattati
L1-L2
L2-L3
L3-L4
L4-L5
L1-L2/L2-L3
L2-L3/L3-L4
L3-L4/L4-L5

5. Diagnosis on admission
imaging
DDD
DDD +
stenosis
DDD + DH
Symptoms
BP
BP + RP

6. 0
10
20
30
40
50
60
70
80
1 2 3 4 5 6 7 8 9
ODI pre
ODI post

7. Stand alone XLIF: results
after 3-months FU
0
1
2
3
4
5
6
7
8
9
1 2 3 4 5 6 7 8 9
VB pre
VB post

8. Stand alone XLIF: results
after 3-months FU
0
1
2
3
4
5
6
7
1 2 3 4 5
VL pre
VL post

9. Stand alone XLIF: results
after 6-months FU
0
10
20
30
40
50
60
70
1 3 5 7 9 11 13 15 17 19 21
ODI pre
ODI post 3
ODI post 6

10. Stand alone XLIF: results
after 6-months FU
0
1
2
3
4
5
6
7
8
9
10
1 3 5 7 9 11 13 15 17 19 21
VB pre
VB post 3
VB post 6

11. Stand alone XLIF: results
after 6-months FU
0
1
2
3
4
5
6
7
8
9
1 2 3 4 5 6 7 8 9
VL pre
VL post 3
VL post 6

12. Results analysis
• Most cases show good outcome with progressive improvement at six month
FU
• Unmodified or worsened ODI and VAS scores are classified as poor
outcome
• Limited improving of scores at three-six months FU that doesn’t lead to
category shifting is considered as no satisfactory (poor outcome)
• After 3 months FU, 4 out of 9 patients did not significantly improve; of these,
three had limited improvement but didn’t change ODI category, one had bad
outcome with ODA/VAS scores worsening.
• After six month, 1 out of 22 patients didn’t improve significantly
• Data matching at three and six months shows progressive outcome
improving

13. Stand alone XLIF: pitfalls
• Radiological study at three and six months with lateral Flexion-Extension X-
Rays didn’t show significant bone formation
• 8 out of 23 patients (34,8%) showed radiological evidence of subsidence of
the cage at six months FU
• 3 out of 9 patients (33%) showed radiological evidence of subsidence of the
cage at three months FU
• 7 out of 11 cages were 18 mm wide.
• Subsidence was identified in one case of poor outcome at three month FU
(22mm CoRoent XL)
• No subsidence in the case of poor outcome after 6-months FU
• In 10 cases subsidence was clinically silent

14. Poor outcome analysis
• Back pain in three cases, back pain + radiculopathy in 2 cases
• Subsidence in one case (BP + RP)
• Single level (L3-L4) interbody fusion in two levels degenerative disc
disease (L3-L4/L4-L5): procedure aborted in L4-L5.
• Persistent foraminal stenosis in one case
• No clear causes of persistent symptoms in two cases

15. Stand alone XLIF: implant
failure
• GR, female, 66 Years-old, previous L4-L5 PL arthrodesis in L5-S1
grade two spondylolishtesis, osteoporosis
• Symptoms: invalidating low back pain, lower limbs radicular pain
with cladicatio spinalis, walking severely restricted
• Clinical examination on admission: segmental paresis in extension
of left foot, Lasegue + 40° in left lower limb
• Pre-op LS MRI: L5-S1 grade II spondylolisthesis with spontaneous
fusion, L4-L5 pedicle screws with left L5 screw malposition, adjacent
level discopaty with Modic 1 changes of the endplate, right convex
scoliosis with L3-L4 apex.
• Surgical planning: L3-L4 stand alone XLIF to achieve mild coronal
deformity correction and treat adjacent level discopathy, L4-L5
laminectomy to decompress left L5 nerve root

16. Peri-operative complications
• Right side surgical approach with MAXcess, standard fashion
discectomy, 18x55x8 mm parallel trial followed by 18x50x10 mm
parallel trial then 22x50x10 mm lordotic trial
• No evidence of subsidence during the discectomy and trial
introduction, but significant bleeding from the disk space started
after last steps
• Cage dislocated in the cranial third of L4 vertebral body (22x50x10
lordoticl); bleeding stopped just after cage insertion, the implant was
tightly positioned in the L4 body
• We decided to leave the implant there and go on with posterior
decompression

17. Stand alone XLIF