Pterion Prep CraniPro VUMC Case Prep
2026-06-27

Case Prep: EC-IC Bypass (STA-MCA)

Case / Approach Snapshot

One-Liner

[Age]yo [M/F] with [moyamoya disease / symptomatic ICA or MCA occlusion / complex aneurysm requiring flow replacement] planned for [left/right] STA-MCA bypass [± indirect revascularization (EDAS/EDAMS)].

Figures, Imaging & Video

🎥 Operative video — search operative video on YouTube ▸ · The Neurosurgical Atlas ▸

🧭 Operative approach: Pterional craniotomy — detailed corridor setup, step-by-step technique & figures

External sources — operative figures/atlases are copyrighted (linked, not copied). See media-sources.md.

Operative technique & approach

Imaging

Open-access figures

High-Yield Literature

Curated Image Set

Open-access figures are embedded from PubMed Central articles and kept unique to this guide.

EC-IC Bypass — Figure 1 Figure 1. Source: Comparison of outcomes and utilization of extracranial–intracranial bypass versus intracranial stenting for intracranial stenosis — Surg Neurol Int. 2014 Dec 11;5:178. doi: 10.4103/2152-7806.146831; CC BY-NC-SA.

EC-IC Bypass — Figure 2 Figure 2. Source: Comparison of outcomes and utilization of extracranial–intracranial bypass versus intracranial stenting for intracranial stenosis — Surg Neurol Int. 2014 Dec 11;5:178. doi: 10.4103/2152-7806.146831; CC BY-NC-SA.

EC-IC Bypass — Figure 3 Figure 3. Source: Comparison of outcomes and utilization of extracranial–intracranial bypass versus intracranial stenting for intracranial stenosis — Surg Neurol Int. 2014 Dec 11;5:178. doi: 10.4103/2152-7806.146831; CC BY-NC-SA.

EC-IC Bypass — Figure 4 Figure 4. Source: Comparison of outcomes and utilization of extracranial–intracranial bypass versus intracranial stenting for intracranial stenosis — Surg Neurol Int. 2014 Dec 11;5:178. doi: 10.4103/2152-7806.146831; CC BY-NC-SA.

EC-IC Bypass — Figure 5 Figure 5. Source: Comparison of outcomes and utilization of extracranial–intracranial bypass versus intracranial stenting for intracranial stenosis — Surg Neurol Int. 2014 Dec 11;5:178. doi: 10.4103/2152-7806.146831; CC BY-NC-SA.

EC-IC Bypass — Figure 1 Figure 1. Trends in utilization of intracranial stenting and extracranial–intracranial bypass procedures for revascularization of patients with intracranial stenosis Source: Comparison of outcomes and utilization of extracranial–intracranial bypass versus intracranial stenting for intracranial stenosis — Surgical Neurology International 2014; CC BY-NC-SA.

EC-IC Bypass — Figure 1 Figure 1. Extracranial–intracranial bypass surgery utilization trend for cerebrovascular steno-occlusive disorders using Florida and New York State Inpatient Databases Source: Utilization and safety of extracranial–intracranial bypass surgery in symptomatic steno-occlusive disorders — Brain Circulation 2019; CC BY-NC-SA.

EC-IC Bypass — Figure 2 Figure 2. Trends in 30-day risk of death, stroke, or hemorrhage following extracranial–intracranial bypass surgery using Florida and New York State Inpatient Databases Source: Utilization and safety of extracranial–intracranial bypass surgery in symptomatic steno-occlusive disorders — Brain Circulation 2019; CC BY-NC-SA.

EC-IC Bypass — Figure 1. Figure 1.. Three-dimensional (3D) reconstruction of the patient’s previous craniotomy (left) and intracranial vascular system with recurrent aneurysm thrombosis and surgical clips before… Source: Extracranial-Intracranial Microsurgical Bypass Using a Y-Shaped Vein Graft From the Hand — Plastic Surgery 2024; CC BY-NC.

EC-IC Bypass — Figure 2. Figure 2.. Preoperative digital subtraction angiogram (left internal carotid injection) of the giant partially thrombosed left MCA aneurysm. Source: Extracranial-Intracranial Microsurgical Bypass Using a Y-Shaped Vein Graft From the Hand — Plastic Surgery 2024; CC BY-NC.

History of Present Illness

Imaging Review

DSA (gold standard)

MRI / Perfusion (CT perfusion, MR perfusion, acetazolamide challenge SPECT)

CTA

Labs

Neurological Examination

Surgical Planning

Case Logistics, OR Needs & Orders

Position

Approach: STA-MCA Bypass

Key Surgical Steps

  1. Harvest STA donor — Doppler-mapped; dissect STA (frontal or parietal branch) with a cuff of surrounding tissue; preserve adventitia; control side branches with microclips/bipolar; obtain adequate length
  2. Protect the donor — papaverine-soaked gauze; keep moist
  3. Craniotomy — small craniotomy centered over the chosen cortical recipient MCA branch
  4. Open dura, identify a suitable M4 cortical recipient (≥ 1 mm, relatively straight segment)
  5. Prepare recipient — dissect free, place background, temporary clips proximal and distal, arteriotomy
  6. Prepare donor — fish-mouth the STA end, flush with heparinized saline
  7. Anastomosis — end-to-side STA-to-M4 with 10-0 nylon interrupted sutures under high magnification
  8. Release temporary clips — distal then proximal; confirm flow
  9. Confirm patency — ICG videoangiography, micro-Doppler, flow probe
  10. Indirect adjunct (moyamoya): EDAS (encephalo-duro-arterio-synangiosis) — lay STA/galea/dura onto cortex for neovascularization; or EMS (temporalis muscle)
  11. Closure — ensure bone flap/dura do not kink the graft (bone removal at graft entry, loose dural closure)

Critical Anatomy & Structures at Risk

  1. STA donor — avoid intimal/adventitial injury, kinking, twisting
  2. Recipient M4 — atherosclerotic vessels harder to anastomose
  3. Graft entry point — must not be compressed by bone/dura
  4. Frontalis branch of facial nerve — during STA harvest (anterior dissection)

Equipment

Monitoring

Anesthesia

Potential Complications

  1. Graft thrombosis/occlusion
  2. Hyperperfusion syndrome (moyamoya) — headache, seizure, hemorrhage; BP control
  3. Ischemic stroke during temporary occlusion
  4. Wound healing issues (STA was scalp blood supply)
  5. Frontalis weakness

Operative Note Template

Preoperative Diagnosis: [Moyamoya disease (Suzuki stage __) / symptomatic ICA or MCA occlusion with impaired cerebrovascular reserve / complex aneurysm requiring flow replacement]

Postoperative Diagnosis: Same

Procedure: [Left/Right] STA-MCA bypass [with indirect revascularization (EDAS)]

Surgeon / Assistant: Anesthesia: General endotracheal EBL / Fluids: Adjuncts: Handheld Doppler (STA mapping), microscope, ICG videoangiography, micro-flow probe Implants: 10-0 nylon anastomosis suture Monitoring: EEG / SSEP / MEP — stable [note changes during temporary occlusion] Complications: None

Indications: [Age]yo [M/F] with [recurrent TIAs/strokes from moyamoya / symptomatic ICA occlusion with failed medical therapy and impaired reserve] and angiographic candidacy for revascularization. Aspirin was continued perioperatively. Risks/benefits/alternatives discussed.

Description of Procedure: After consent and time-out, general anesthesia was induced maintaining normotension and normocapnia, and neuromonitoring established. The STA was mapped with handheld Doppler. The head was fixed and the donor STA ([frontal/parietal] branch) was harvested with a periadventitial cuff, side branches controlled, and the vessel protected with papaverine-soaked gauze.

A craniotomy was performed centered over a suitable cortical M4 recipient (≥1 mm). The dura was opened, the recipient prepared on a background, and temporary clips placed proximally and distally with an arteriotomy made. The STA end was fish-mouthed and flushed with heparinized saline, and an end-to-side STA-to-M4 anastomosis was completed with interrupted 10-0 nylon under high magnification. Temporary clips were released (distal then proximal) and patency confirmed by ICG videoangiography, micro-Doppler, and flow probe. [An EDAS was performed by laying the STA/galea onto the cortical surface.]

The bone flap was contoured to avoid graft compression, the dura closed loosely around the graft, and the scalp closed without kinking the pedicle. The patient was transferred to the NSICU in stable condition.

Postoperative Plan

Chief-Level Case Review

Use these as the senior-level mental model for EC-IC Bypass (STA-MCA):

Common Pimp Questions

Use these to pressure-test preparation for EC-IC Bypass (STA-MCA):

  1. What is the proximal-control plan before the lesion is manipulated?
  2. Which branch, perforator, or venous structure is most likely to be injured in this exposure?
  3. What are the intraoperative rupture steps, including temporary clip, suction, BP, and backup clip strategy?
  4. What confirms treatment success: ICG, Doppler, puncture/deflation, DSA, or postoperative CTA?
  5. What postoperative BP, vasospasm, antiplatelet, or anticoagulation issue changes the orders tonight?

Attending Preference Variables

Items that commonly vary by surgeon or institution: