AVMs of the Posterior Fossa

Case Presentation and Literature Discussion

Christopher ShowersColumbia University College of

Physicians and Surgeons

Patient CP - HPI

• USH eating dinner sudden onset very severe R H/A with lightheadedness, nausea

• Progressive lethargy LOC en route to CCH• Upon Arrivals: Decorticate Posturing

Intubated; CT head acquired • Emergent R Frontal EVD transfer MGH

Outside H-CT8/14/13 21:13

Patient CP - MGH

• Exam:– Intubated, sedated, no follow commands– L anisocoria (4/3mm) nonreactive b/l, (-)corneals,

(-)OCR, (+)cough, flexion RUE, TF in LLE– GCS: 4-5

• Labs: Na 123; K 5.7• Drips: Mannitol x1; 23% NaCl x2 3% NaCl • EVD: at 0, open no drainage • Repeat CT Head: interval mild progression of

hemorrhage, hydrocephalus

Patient CP

• PMx: L Humoral fracture 1.5wk ago• Meds: ASA 81mg qD; Duloxetine 60mg qD• ROS: L arm pain; no complaints prior • SHx: retired teacher, nonsmoker, active at b/l• FHx: no sudden bleeds

Preop Angio8/15/13 08:30

Right Vertebral Injections

Operative Resection

• SMG 2-3 (1-2S, 1E, 0V)• SOC evacuation of hemorrhage / resection

of AVM; placement of R occipital EVD– Washout of subdural blood– Ligated feeding arteries, identified abnormal

superior vein draining AVM– Another nidus identified anterior superior, not

visualized on angio

Intraop Angio8/15/13 17:02

Right Vertebral Injections

Operative Resection x2

• Rentered initial craniectomy site– Wider area of dissection extensive & diffuse

abnormal vessels draining into large vein extending superiorly

– Skeletonized large vein with generous R cerebellar resection Witnessed to turn blue

• NICU

Post-op H-CT8/15/13 21:38

Post-op Exam

• Pupils symmetric, reactive 32mm b/l• No OCR, vertical bobbing• Mild cough reflex• UE: withdraw to pain b/l• LE: TF b/l

• Deteriorated to extensor posturing UE/LE b/l• Expired on 8/21/13 01:35am

Posterior Fossa AVMs

• 7.5% - 20.0% of all intracranial AVMs (da Costa 2009; Drake 1986; Perret 1966)

– 72.4% Cerebellar / 21.5% Brainstem (da Costa 2009)

• Vermian most common (Sampson 2004)

– Arterial Input distal SCA & distal PICA b/l– Large or involving 4th V deep AICA feeders– Venous Drainage Superiorly to Galenic System

• Greater Rate of Hemorrhage in PF-AVMs– Hemorrhage as presenting symptoms ~90% vs. 29-

54% in ST (Khaw 2004; Stefani 2002; Drake 1986; Solomon 1986)

– Smaller size vs. ST increased hemorrhage risk (Drake 1986; Sampson 1986; Kader 1994; Langer 1998)

– Greater Rate of AA 25% vs. 5-8% in ST (Sampson 1997; Lanzino 1999)

– Bleeds more frequent and FATAL up to 66.7% (Fults and Kelly 1984; Batjer 2009; Symon 1995

– Rebleeding in 6.0% - 17.8%, 34.3% Dw/DD (Mast 1997; Stapf 2006; Steinberg 2008)

• 5-6% annual risk up to 5 years (Halim 2004) vs. 3-4% ST (Baskaya 2006)

Presentation of PF-AVMs

• Rarely present with Seizure– 2/68 (2.9%) attribute to hydrocephalus (Yasargil 1998)

• General Neuro deficits / CN palsy up to 28% (Batjer 2009; Stahl 1980)

– Mass effect– Ischemia – steal phenomenon – Hydrocephalus– CN V palsy

Presentation of PF-AVMs

Treatment • Optimal to defer surgical resection 4 – 6 wks

after initial hemorrhage and clot evacuation– Not possible w/ Life threatening bleed– 53 pf-AVMs 15 emergent operation, AVM

removed at time of evaluation in all (Sampson 2004)

• Preoperative Embolization recommended – Occlude small feeders difficult to locate surgically• Caution occluding large vessels proximally

– Great Benefit in Brainstem AVMs– Mortality 1.3% ; Severe-Mod AE 6.7%, 15.3% (Wikholm

1966)

• Radiosurgery GKRS– Small, unruptured, eloquence, elderly (Ciurea, 2010)

– Latency of obliteration after treatment no abatement of risk in that time (Ciurea 2010)

– GKRS Obliteration: 63% 2y; 73% 3y - 95% stable neurologically (Massager 2000)

• Multimodal Therapy recommended (Steinberg 2008)

– SMG III-IV, mostly brainstem AVM– XRT alone residual AVM on f/u

Treatment

General Outcomes

• Excellent to Good outcomes 71.0% - 82.1%• Poor morbid outcome 13.0% - 22%• Mortality 3.6% - 16.7%(Solomon 1986, Samson 1986; Symon 1995; Drake 1986; Steinberg 2008)

Outcome Associations • 12 pf-AVM w/ hemorrhage (Yilmaz 2011)

– Worse w/ initial mRS, SMG grade, hematoma size• 59 pf-AVM w/ hemorrhage (van Loon 1993)

– Worse w/ degree of 4th V compression, GCS• 98 pf-AVM – 61/98 (62.2%) w/ Hemorrhage (da Costa 2009)

– Worse w/ presence of AA, initial mRS, # of treatments• 48 pf-AVM SMG III-IV (Steinberg 2008)

– 37/48 (77.1%) w/ Hemorrhage; mean f/u 4.8y– Multimodal therapy >> XRT alone

Acknowledgments

• CP&S – Dr. Jeffrey Bruce – Dr. Donald Quest

– SD Andrew Chan– SD Brian Gill

• MGH– Dr. William Butler – Dr. Patrick Codd– Dr. Chris Stapelton– Dr. Peter Fecci

NOTES BELOW HERE

Posterior Fossa AVMs• da Costa 2009– 106 / 678 (15.6%)

• 72.4% Cerebellar / 21.5% Brainstem

• Cooperative Study of Intracranial Aneurysms and SAH (Perret 1966)

– 32/453 7%• Drake 1986– 116/600 20%

• Vermian most common (Sampson 2004)

– Arterial Input distal SCA & distal PICA b/l– Large or involving 4th V deep AICA feeders– Venous Drainage Superiorly to Galenic System

Hemorrhage in PF-AVMs

• Brugge, 2010– 61/98 (62.3%) presented with Intracranial hemorrhage– Hemorrhage reduced mRS at presentation

(p=0.0229) though not final mRS (p=0.41)– AA, poor initial mRS, treatment reduced final mRS– 52 f/u imaging

• 48.9% completelly obliterated • 13.4% smaller but patent nidus• 9.6% uchanged

– 10/61 hemorrhaged in f/u 4.1% risk/year• No difference in treated vs. untreated