1. Pseudarthrosis Daniel CHOPIN Pôle Neuroscience et appareil Locomoteur
Clinique de neurochirurgie
Unité Rachis Neuro-Orthopédique
Hopital Roger Salengro
Université de Lille
VII convention of the Russian Association of Spinal jsurgeons in conjonction with SRS WW course May 2016

2. Bone Union
Healing process is a multifactorial process including biological and mechanical factors.
No clear cut definition of non union: documented failure of solid union after 1 year
New technologies (instrumentations, graft expenders, osteoinductive substances) have reduced dramatically the rate of non-union in pediatric and young adults spinal deformity surgery.

3. Pseudarthrosis
BUT
Pseudarthrosis remain the major cause of reintervention in adult spinal deformity surgery
17% to 23,3%
D.B Pateder et all Spine 2006
Y.Kim et all Spine 2006
M.Kelly et all Spine 2013
H. Koller et all Eur Spîne J 2015
VII convention of the Russian association of Spinal surgeons in conjonction with SRS WW course May 2016

4. Clinical symptoms After post-operative improvement: Axial Pain
Leg pain referal
Recurence of deformity
Increasing sagittal/ coronal imbalance
around 1y after surgery.
But may be completely asymptomatique for many years.(Detection between 1 and 5y, up to 10y!)

5. Radiological Plain Xrays Lucency around implants
Rod fracture : non-union in ½ and ¾ of symptomatic patient C.Barton et al Scoliosis 2015
Hook-screw pull-off
Loss of correction
Imbalance
VII convention of the Russian association of Spinal surgeons in conjonction with SRS WW course May 2016

6. 56y PO
1year PO

7. Radiological CT scan with sagittal and coronal reconstruction.
Radionucleotide scans
VII convention of the Russian association of Spinal surgeons in conjonction with SRS WW course May 2016

8. Risk Factors Age >55-65y Comorbodities Long fusion >12 v
Osteotomies (PSO,VCR)
Fusion to the Pelvis
Thoraco-lumbar kyphosis > 20°
Sagittal imbalance
VII convention of the Russian association of Spinal surgeons in conjonction with SRS WW course May 2016

9. Fusion to pelvis 35 to 44% of all pseudarthrosis Prevention
Sacro pelvic fixation with iliac screws lower by 50% the non union rate compare to isolated sacral screw (Kim spine 2006).
Anterior structural support of any high disc at LS junction
VII convention of the Russian association of Spinal surgeons in conjonction with SRS WW course May 2016

10. Iliac Screw Fixation
D. Chopin 1987
Biomechanical study: McCord 1992

11. 55y
58y
3y po extension to S1

12. Sagittal Balance Increasing risk with greater preop imbalance
Increase risk with post-op imbalance
C7 SVA >5cm
Small post-op Lumbar Lordosis (an increase by 35° of LL reduce the risk of non-union by 50%) PT
Kim YJ Spine 2006 :positive sagittal balance>5cm at 8 weeks
D.Pateder Spine 2006 TL Kyphosis >20°, greater sagittal imbalance.
H. Koller Eur. Spine J 2015
VII convention of the Russian association of Spinal surgeons in conjonction with SRS WW course May 2016

13. 3 column Spinal Osteomies
10,6% symptomatic non-union
61,1% PSO level
3 to 4 rods construct
2RC 17% rod breakage half requiring revision
4RC 3% partial implant failure .no revision
Anterior column support of adjacent high discs
S-J Hyun et al spine 2014
D. Dickson et al Spine 2014
VII convention of the Russian association of Spinal surgeons in conjonction with SRS WW course May 2016

14. Biology Meticulous decortication: good vascular environment
Autogenous Iliac Crest Bone Graft: gold standard, osteogenic, osteoconductive, osteoinductive
Osteoconductive substances (ceramics, allograft)
Osteoinductive:
bone marrow aspirate R. Ajiboye et al Eur Spine J 2015
rhBMP:
VII convention of the Russian association of Spinal surgeons in conjonction with SRS WW course May 2016

15. BMP K Guppy et al Spine 2014 Ra’K Rahman et al Spine 2013
9425 spine fusions: no difference with or without BMP
Ra’K Rahman et al Spine 2013
Long fusion to pelvis :fusion rate at L5S1 no difference between rhBMP alone or associated TLIF.
J. Paul et al Spine 2016
Long fusions for ASD reoperation for non union:
5% with BMP 33,9% without BMP

16. Management
Rod breakage asymptomatic, good balance , distant from index surgery: observation.
Symptomatic, implant failure, imbalance, loss of correction:
Revision of all the fusion mass (multilevel pseudarthrosis)
Restoration of balance including major osteotomies
Solid pelvic fixation, multilevel Pedicular Screws
BMP, bone extenders
Anterior support of high open discs

17. 69 years

18. Conclusions Pseudarthrosis is the most frequent cause of reoperation
Despite third generation instrumentations, bone extenders and osteoinductors, the rate is still high.
Selection of patients, restoration of coronal and sagittal balance are of first importance as well as mechanical and biological ressources.
More work must be done to improve the rate of fusion in patients at risk.
VII convention of the Russian association of Spinal surgeons in conjonction with SRS WW course May 2016