Microsurgery for cerebral AVM: postoperative outcomes & predictors of complications in 264 cases, by Theofanis et al, from Neurosurg Focus, 2014 --Topik journal reading-ku pas stase Neurosurgery..

1. M i c r o s u r g e r y
f o r
C e r e b r a l
A r t e r i o v e n o u s
M a l f o r m a t i o n s
postoperative outcomes &
predictors of complications
in 264 cases
Theofanis T, Chalouhi N, Dalyai R, Starke RM,
Jabbour P, Rosenwasser RH, Tjoumakaris T
Neurosurg Focus 37 (3):E10, 2014

2. AVM
Vascular lesions composed of tortuous arteries and veins
without intervening capillaries.
• Found in approximately 0.1% of the US population
• Responsible for approximately 2% of all hemorrhagic strokes,
make up a particularly high percentage of hemorrhagic strokes
in patients < 40 years
• Annual risk of ICH: 1% - 25%
• Due to the high risk of rupture in select AVM patients,
intervention is an appropriate option
AVM resection
• was associated with significant morbidity and mortality.
Microsurgical excision
• Complete cure/ elimination of AVMs is more attainable over the
past decades
• Option in select patients due to the lack of a latency period for
hemorrhage / low risk of future recurrence

3. Lancet 2014; 383: 614–21
Microsurgical outcomes are arguably one of
the biggest aspects lacking from the ARUBA trial
5 patients in the treatment arm received open surgery
[embolisation + surgery (12 px) | embolisation + radio + surgery (1 px) ]
Stopped prematurely after a safety analysis

4. Objective
• to assess the safety and efficacy of microsurgical
resection of AVMs
• determine predictors of complications

5. Methods
Prospectively maintained database for patients with AVMs, underwent microsurgical resection,
at Jefferson Hospital of Neuroscience, between 1994 - 2010
264 patients [from 774 patients with cerebral AVMs]
Surgical Techniques : permanently eliminating AVM, preserving full neurological function,
reversing deficits
Selecting the best therapy by
doctors trained in 3 field
Treatment decision: doctor +
px
Embolization
Review
Medical charts, imaging studies, and follow-up notes, SM grade, initial hemorrhage, clinical
presentation, treatment modalities, clinical outcomes, obliteration rates

6. Outcome
Statistical analysis
unpaired t-tests, Chi-square, Fisher’s exact tests, ANOVA, univariate & multivariate analysis
| p ≤ 0.05 | Stata 10.0
Assessment of AVM
obliteration: intraoperative
angiography
Neurological examination
pre- & post-surgery
modified Rankin Scale at
arrival & discharge

7. Results
Unruptured AVM SM grade
I : 9% II : 45.8% III : 34.8% IV : 9% V : 1.4%
Unruptured AVM size
<3 cm : 78 3-6 cm : 62 > 6 cm : 4

8. Modalities
Prior Embolization
102 patients (38.6%)
6
session
1 px
3
session
10 px
5
session
1 px
2
session
19 px
4
session
4 px
1
session
67 px
Prior Gamma
Knife Procedure
16 px (6%)
1-
stage
12 px
2-
stage
4 px
Combination all modalities
10 px
Microsurgery
alone
Rupture
7 patients
Rupture
2 patients

9. 3.4% Post-op seizure (9)
3% Post-op VP shunt (8)
2.7% Death | At arrival: GCS ≤ 8, ruptur
1.9% Permanent neurological deficits
-Hemiparesis (2)
-Hemiplegia (1)
-Aphasia (1)
-Vegetative state (1)
1.9% Post-op infection (5)
264 patients
Microsurgery
100% Complete AVM obliteration
0% Post op hemorrhage
86.4% Favorable outcome (mRS 0-2)
92.4% Clinically unchanged
6.9% Minor neurological deficits (10)
3.5% Post-op seizure (5)
1.4% Post-op VP shunt (2)
0.69% Died (1)
0.69% Permanent neurological deficit (1)
0.69% Post-op infection (1)
144 patients
Unruptured
AVMs
AVMs of SM
Grade III/higher
accounted for
the majority of
the compli-cations

10. Embolization (-) Embolization (+)
Complication 5.7% 9.4%
Unruptured Hemorrhage
mRS at discharge 0.074 1.22

11. Discussion
Historically, surgery is reserved for hemorrhage,
intractable epilepsy, progressive worsening
Heros & Tu, 1985 |
Rates of surgical Morbidity Mortality
Unruptured (49) 14.2% 0%
Rupture (54) 16.6% 1.6%
Present study |
data on a large single-center
series of patients :
2.7% death & 1.9% permanent
neurological def.
Study: Dismal natural history of untreated AVM
• The possibility of AVM rupture is one that
should receive great weight in counseling
patients on the decision of if, how, and
when is best to treat the AVM
• AVM detection prior to rupture remains a
challenge
• Possible direction of future research is to
elucidate which patients may be identified
as candidates to screen for a cerebral AVM.
All deaths were in
patients who
presented with
hemorrhage and
underwent urgent
surgery.

12. Unrupture AVM
Lawton et al, 2005
• 224 px AVM microsurgery
• Outcome: mRS
• Hemorrhagic presentation : 54%
 improved after procedure
• Unruptured AVMs:
– Normal/nearly normal
neurological function at
presentation
– Susceptible to worsening (slight)
• 6.7% px died
• Hemorrhagic brain injury and its
secondary effects (pre-procedure)
may mask the surgical morbidity.
• Sensitive measures of clinical
outcomes (mRS) are more likely
to reveal slight changes in
patients who initially were
essentially without symptoms.
• Counseling patients : important
to note that even subtle
postoperative deficits can be
easily detected
Operative intervention in patients with unruptured AVMs should be seriously
considered at high-volume experienced centers .
The patients who can benefit the most :
- Good candidates for surgery
- Lesions with characteristics & angioarchitecture high risk for rupture

13. Preoperative Embolization
• Safely decrease the
size of AVMs
• Decrease the apparent
risk of rupture in high-risk
lesions
• Eliminating deep
feeding vessels
• Operative blood loss
can be greatly
minimized
Previous studies:
highlight favorable
clinical outcomes of
multi-modality
therapy for carefully
selected patients

14. Nataraj et al
265 px
Rupture + Unrupture
GOS
(favorable/
score 4-5)
Embolization 
microsurgical
resection
86%
Microsurgical
resection alone
96.5%
Presurgical embolization
• Marker of patients with more
complicated AVM
angioarchitecture / high-risk
for surgery
• Potentially risky:
– possibility of decreasing the
flow too much in one area 
increased flow in other areas of
the nidus / cerebral vasculature
– diminishing venous outflow
from embolization could cause
AVM rupture

15. AVM size
Stüer et al:
• Small- and medium-sized AVMs : dynamic autoregulatory function seems
to be intact in the surrounding cerebrovascular bed perioperatively.
• Larger AVMs : more likely to have more draining veins & risk for
postoperative breakthrough complications.
• Emphasizes the importance of AVM size for
stratification of surgical risk
AVM size: strong independent
predictor of surgical
complications
• More data on microsurgery treatment in a
larger group of cases with high SM grade
To elucidate specific
components of the SM grading
scale that can predict
favorable operative outcomes
in high-grade lesions

16. Microsurgery & ARUBA Trial
The majority of patients in the ARUBA trial treatment arm received noninvasive and non-neurosurgical
treatments
Russin and Spetzler: it remains difficult to resolve why only 5 patients received resection
alone when 76 patients in the treatment arm had Grade I or II AVMs.
Present data are encouraging. With modern-day techniques & approaches, microsurgery
can be undertaken with extremely low complication rates and provide excellent outcomes
for patients
A trial comparing microsurgery and medical management is necessary to begin exploring the
unanswered questions and clinical discrepancies raised by the ARUBA trial

17. Limitations
• Retrospective data analysis
• Single-center study
• Recall bias

18. Conclusion
• Microsurgical resection of AVMs is highly efficient
and can be undertaken with low rates of
morbidity at high-volume neurovascular centers.
• Unruptured and larger AVMs were associated
with higher complication rates

19. END.
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