1. GAMMA KNIFE RADIOSURGERY FOR AVMs AT QUEEN SQUARE GK CENTRE

2. Brief History
2012: partnership between University College London Hospitals NHS Foundation Trust
and Medical Equipment Solutions Limited Company
October The first GK procedure
January First publication from QSRC on the conformal treatment of AVMs
April Official opening of our centre
April th patient treated at the centre
November th patient treated at the centre
June QSRC/UCLH – 7 years contract with NHS England to treat all 4
tiers as a new NHS implementation plan
October 2016 First paediatric patient treated for AVM
June More than 750 patients treated at our centre

3. QSRC Team Consultant Neurosurgeons (10) Therapeutic Radiographers
Mr N Kitchen – Medical Director
Mr R Bradford
Miss J Grieve
Miss M Murphy
Mr A McEvoy
Mr L Thorne
Miss H Sethi
Mr J Hyam
Mr G James – paediatric
Mr M Tisdall - paediatric
Therapeutic
Radiographers
K Jeanson
M Kilkenny
A Polonsky
MDT Coordinator
Sam Atrey
Administrative
E Brooks
L Murray
Nurse
G Jimenez
Physicists –
Medical Physics Limited
Ian Paddick
Alex Dimitriadis
Phil Tapper
Clinical Fellow
Cornel Tancu
Consultant Neuroradiologists
Dr K Miszkiel
Dr T Solbach
Dr P Rangi
Dr M Adams
Dr F Roberson - paediatric
Dr A Rennie - paediatric
QSRC Executive Director
Lynne Brooks
Local Manager Mike Allcock

4. GK procedures for AVMs 140 procedure up to date
n=122
n=165
n=177
n=178
15.7%
25%
18.8%
12.4%
140 procedure up to date
18% from a total of 642 procedures from October 2012 to December 2016

5. Day procedure under L.A.

7. AVM n: 140 Volume: 1.85 cc (0.02 – 8.73cc) References:
Ding et al 2014 (n:639): 3 cc (0.1-33)
Ding et al 2013 (n:444): 4.2 cc (0.2-29)
Nagy et al 2012 (n:492); 14.3 cc
References
Prescription dose: Gy (Mean=23.6Gy, Median=25Gy)

8. Obliteration confirmed: 1
AVM n: 70
Previous treatments:
None: 68%
Embolisation: 22%
Surgery: 5%
GK: 5%
Obliteration confirmed: 1
Interim bleeds: 1
Spetzler-Martin:

9. Side effects – AVMs 10% (n:8)
Ding et al 2014 (n:639): 11.6%
Severe headache n:
Increased number of seizures % (n:5) %
Severe dizziness/ataxia n: 1 brainstem
Figure xx shows reduced susceptibility in a small area of the right cerebellar hemisphere in that patient who presented with transient aphasia, left upper limb weakness and confusion a few minutes after CCA. The GK procedure was aborted and the patient recovered completely (without neurological deficit) after several similar episodes of transient neurological deficit in the first four hours after diagnostic angiography.

10. AVM Radiosurgery- Historical perspective
Author SRS treatment # of Patients
Kjellberg Proton beam 1329
Steiner GK
Forster GK
Lunsford GK
First GK for AVM was performed by Steiner in 1968
Steiner L, Leksell L, Backlund E. et all, 1972
Tracking data provided by the manufacturer of the Gamma Knife, AB Elekta, indicated that more than 60,000 patients worldwide had undergone radiosurgery for AVMs by 2011.

11. What are the limiting factors of radiosurgery in AVMs?
In-field AVM obliteration
after
GKS
(N=802)
Volume
Volume < 5 cc: 80-90%
Volume > 10 cc: < 20%
< 4cc (N=458)
4 - 8cc (N=218)
> 8cc
0.8%
3.5%
18.1%
37.1%
50.6%
65.8%
58.5M
4-8cc
2.0%
16.1%
39.1%
65.7%
75.6%
87.1%
39.9M
< 4cc
7.1%
32.2%
55.6%
74.2%
82.2%
92.1%
31.5M
1 year
TO rate =
2 year TO rate =
3 year TO rate =
4 year TO rate =
5 year TO rate =
10 year TO rate = Median TO time =
> 8cc (N=137)

12. A dose-response analysis of AVM obliteration by radiosurgery Flickinger et al, IJROBP, 1996

13. Univariate Statistical Analysis in 803 patients
Smaller target volume and higher margin dose were associated with
higher total obliteration rate and lower bleeding rate after GKS.
Prior bleeding and NO prior embolization history were associated with higher obliteration rate.
Presence of varix or aneurysm was associated with higher bleeding rate after GKS.
Higher Pollock-Flickinger score
= 0.1 x Volume(cc) x Age(years) + (0.5)x Location:(BS,TH, BG=1,others=0)
was significantly associated with lower total obliteration rate and higher bleeding rate after GKS.

14. Risks of adverse radiation effect (ARE) are related to volume, dose
Adverse Radiation Effect after GKS (N=802)
Risks of adverse radiation effect
(ARE)
are
related to
volume, dose
and
location
‘12Gy Volume’
46 cases (5.7%) – Pittsburgh
52 cases from 1024 patients (5%) - Karolinska

15. Adverse Radiation Effect after GKS (N=802)
Univariate analysis of symptomatic adverse radiation effects (N=46)
after GKS in entire casesD(N=802)
Variable (higher risk) p value
Location (non lobar) <0.0005
Target volume (larger)
12Gy volume (larger) <
Maximum diameter (larger)
Margin dose (larger)
Spetzler-Martin grade (higher)
Pollock-Flickinger score (higher) <0.0001

16. 52 y old F presented in August 2013 with seizures, followed by transient right-sided hemiparesis
CT+MRI: left F high-flow AVM with superficial venous drainage

17. GK procedure - 02/12/2013

19. 3.5 y follow-up
2017
2013

20. 31 y old M presented in September 2015 with h/a, LOC and left-sided haemiplegia
CT+MRI: right BG haematoma from rupture of large BG AVM
Dense, compact nidus
Multiple feeding aa, therefore no endovascular options
Large deep draining vein

22. Staged GK procedure
Target volume=5.9 cc; Prescription dose: 20Gy at 46%; 12Gy Vol: 14.3cc

23. For referrals for our Gamma Knife MDT: Sam Atrey MDT Coordinator
Thank you!
For referrals for our Gamma Knife MDT:
Sam Atrey
MDT Coordinator