Multidisciplinary approach to patients with cervical myelopathy: Is it possible to identify the best responders to surgery?

1. Belgrade 23.03.2019
Multidisciplinary approach to
patients with cervical myelopathy:
Is it possible to identify
the best responders to surgery?
Enrico Tessitore MD, PD
Dept. of Neurosurgery
Geneva University Hospitals
Torstein R. Meling MD, DPhil,
FEBNS
Chairman EANS Training Committee
Professor of Neurosurgery

2. Cervical Spondylotic Myelopathy (CSM)
• Chronic condition, mostly elderly
• Degeneration of non-nervous elements (PLL, lig. flavum, intervertebral disk)
 Chronic compression
 Structural modifications:
• Ischemic alterations (microvascular damage)
• Apoptosis, gliosis, edema
• Demyelization and Wallerian degeneration
• Myelomalacia, loss of neural tissue
Nurick S: The natural history and the results of surgical treatment of the spinal cord disorder associated with cervical spondylosis.
Brain 95:101-108, 1972

3. Diagnosis
• Clinical picture
• Radiology
• MRI: T1 & T2 weighted images
(sagittal + axial planes)
• CT
• Plain + Dynamic X-rays
• Neurophysiology (MEP/SSEP)
Cervical Spondylotic Myelopathy (CSM)

4. Management
1. Immobilization with neck brace
2. Wait and see
3. Surgery
Cervical Spondylotic Myelopathy (CSM)

5. Surgery may stop the
disease progression
Surgery may improve
neurological condition
Cervical Spondylotic Myelopathy (CSM)

6. Is it possible to identify the best
responders to surgery by the use
of preoperative DTI?
Cervical Spondylotic Myelopathy (CSM)

7. Diffusion Tensor Imaging
Water molecules normally diffuse through the neural tissue
The apparent diffusion coefficient (ADC) evaluates
quantitatively the impedance of this diffusion
The fractional anisotropy (FA) evaluates flow-uniformity of
water molecules
Premises

8. Diffusion Tensor Imaging
In an ideal tissue, i.e. the water molecules diffuse in a linear
and mono-directional flow, ADC values are low whilst FA values
are high
In a damaged tissue, as in a cervical myelopathy, ADC values
are higher whilst FA values approach 0 because water
molecules tend to move in all directions
DTI can detect microstructural changes in cervical spine before conventional MRI
?
*Kerkovsky M, et al. Spine 2012;37:48-56
*Jones JG, et al. AJNR Am J Neuroradiol 2013; 34:471-478

9. • Prospective, non-randomized observational study
• Single center
• June 2012  June 2018
Materials and Methods

10. Materials and Methods
Inclusion Criteria Exclusion Criteria
Age: 30-81 years Contraindications to MRI
Cervical stenosis at MRI Epilepsy
Need for decompressive surgery Pregnancy
Clinical signs of myelopathy ±
radiculopathy
Cancer or infection
Complete follow-up at 3 months
and 1 year
Previous cervical spine surgery

11. Neurological, Radiological and Neurophysiological Assessment
mJOA , NDI and
Hirabayashi score
Conventional MRI and DTI sequences
(ROIs at surgical space and adjacent levels)
MEP and SSEP
analysis
Before surgery
How?
When?
3 months 1 year
1
2
3
Materials and Methods

12. Materials and Methods
Mean Age 57.1 yrs
Symptoms’ duration
▪ <3 months: 8 pts
▪ 3-6 months: 6 pts
▪ >6 months: 22 pts
Mean preoperative mJOA 13.5
Surgical approach
Anterior: 26 patients (72%)
▪ Single level ACDF: 13 pts
▪ Multiple level ACDF: 7 pts
▪ Corpectomy: 6 pts
Posterior: 10 patients (28%)
36 consecutive patients (13 males, 23 females)

13. Best Responders:
Hirabayashi recovery ratio > 50% 20/36 (55.5%)
NDI improvement > 30% 5/17 (29.4%)
Hirabayashi K et al: Operative results and postoperative progression of ossification among patients with ossification of
cervical posterior longitudinal ligament. Spine (Phila Pa 1976) 6:354-364, 1981
Materials and Methods
Clinical Outcome

14. Clinical Outcome
Significant differences between:
• mJOA values @ 1 yr in best responders vs. normal responders (p=
0.001)
• Preop. vs. postop. mJOA @ 1 yr in best responders (p= 0.001)
0.
6.
12.
18.
preoperative 3 months 1 year
mJOA variation during Follow-up
normal responders best responder
Results

15. Best responders
(20 patients)
Normal
responders
(16 patients)
P-value
Age 58.9 ±13.2 54.6 ±13.1 0.34
Smoke 50% 30% 0.22
T2 hyperintensity 75% 50% 0.13
Diabetes 14 % 5% 0.83
Symptoms >6 mos 75% 82 % 0.14
Individual risk factors
Results

16. Surgery increased cervical canal mid-sagittal diameter
(mean: 100.9%)
Results
Radiology

17. Radiology
No statistical difference in n° patients with
preop. T2 hyperintensity in good responders
and normal responders (p= 0.13)
0
3
6
9
12
15
Normal responders Best responders
N° of patients w/wo preoperative T2
hyperintensity
T2 hyperintensity no T2 hypertintensity
Results

18. Radiology
No statistical difference between preop. FA values in
patients with and without T2 spinal cord hyperintensity (p=
0.96)
Results

19. Significant differences between best
responders and normal responders:
• Preop. FA at most compressed level
(0.63 vs 0.55; p=0.020)
• 1-yr postop. FA at most compressed
level (0.67 vs 0.54; p=0.009)
0.5
0.6
0.6
0.7
0.7
Preoperative 3 months
1 year
FA values at most compressed level
best responders normal responders
Results
Radiology

20. Significant differences between best
responders and normal responders:
• Preop. average FA values
(0.63 vs 0.57; p=0.030)
• 1-yr postop. average FA values
(0.68 vs 0.55; p=0.004)
0.5
0.6
0.6
0.7
0.7
Preoperative 3 months
1 year
Average FA values (level 1-2-3)
normal responders
best responders
Radiology
Results

21. Baseline Fractional Anisotropy >0.55 in 71.5% of best responders vs 28.5% of normal
responders (p= 0.009)
Higher FA positive indicator of good recovery after surgical decompression
0.
20.
40.
60.
80.
normal responders best responders
%
of
patients
FA <0,5 FA >0,5
Results
Radiology

22. Clinical & Radiological analysis
Postoperative Fractional Anisotropy and mJOA values @ 1 yr
Correlation between FA and mJOA scores at 1-year postop. (p=0.0005; R=0.66)
Higher FA positive indicator of good recovery after surgical decompression
0.3
0.4
0.6
0.7
0.8
8 10 13 15 17 19
Fractional
Anisotropy
mJOA
Results

23. Neurophysiological Parameters:
Preoperative MEPs and mJOA
Inverse correlation between preop. central conduction time (CCT) and
mJOA (p=0.0004; R= -0.59)
Restuccia D, et al. Electromyogr Clin Neurophysiol 1992;32:389-395
High diagnostic value of Motor Evoked Potentials
6.
12.8
19.5
26.3
33.
9 11 13 15 17 19
Preoperative
TCC
mJOA
Results

24. Somatosensory-evoked potentials
Importance of tibial nerve SSEPs for prognostication
Positive recovery (@ 1 yr) in patients with normal preoperative N8 latencies
(p=0.007)
0.
22.5
45.
67.5
90.
112.5
abnormal normal
Preoperative N8 latency
normal responders best responders
Results

25. Illustrative cases
2. Hx: 51 y male with weakness of both legs with gait
disturbances and hypoesthesia in both hands past 2
months (mJOA: 10)
Dx: Disk herniation at C4-C5 and C5-C6 with T2
hyper-intensity
Tx: ACDF at C4-C5 and C5-C6
1. Hx: 40 y woman with severe right leg hypoesthesia
past 8 months (mJOA: 15).
Dx: Single-level compression at C4-C5 with no T2
hyper-intensity
Tx: ACDF at C4-C5

26. Illustrative cases
Patient 1 Patient 2
Age 40 51
Entity of compression Single level Double level
T2 hyperintensity No Yes
Preoperative mJOA 15 10
Preoperative
Fractional Anisotropy
0.50 0.67
Preoperative N8
latency
Alterate Normal
Normal responder Best responder
Normal responder Best responder
Patient 1 pre vs post
Patient 2 pre vs post

27. Conclusions
• T2 hyperintensity not predictive of poor recovery
after surgery
• Preop. MEPs related to clinical status
• Normal preop. N8 latency is a positive indicator of
clinical improvement at 1 year
• Baseline Fractional Anisotropy >0.55 is a positive
indicator of clinical improvement at 1 year

28. Acknowledgments
Service de
Neurochirurgie
Service de
Neurologie
Service de
Neuroradiologie
Prof. Karl Schaller Prof. Margitta Seeck Prof. Maria Vargas
Dr. Jeremy Brodard Dr. André Truffert
Dr. Nicolas Broc Dr. Hafid Mekideche
Dr. Rocco Severino Dr. Sc. Colette Boex
Nathalie Isidor Dre. Lascano