photo-1785770609785.jpg
Explain this image
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Reading File
This image illustrates EDAMS (Encephaloduroarteriomyosynangiosis), an indirect cerebral revascularization procedure primarily used to treat Moyamoya disease, particularly in children. The slide appears to be from a neurosurgery lecture or teaching presentation.
What is EDAMS?
EDAMS is a surgical technique that promotes new blood vessel growth (neoangiogenesis) to the ischemic brain by placing vascularized scalp and muscle tissues directly onto the brain surface. Unlike direct bypass (e.g., STA-MCA bypass), it does not immediately connect vessels - it relies on gradual collateral formation over weeks to months.
Panel A - Surgical Top-Down View
This shows the operative field after craniotomy (skull opening):
- The Superficial Temporal Artery (STA) is dissected free from the scalp as a vascular pedicle (preserving its blood supply) and laid across the exposed cerebral cortex.
- The surrounding galea/fascia and temporalis muscle (TM) are also mobilized and placed against the brain.
- The dura mater has been opened and reflected back (or resected), exposing the brain surface.
- The label "EDAMS" points to the overall surgical construct - the layered tissue placement on the brain.
- Sutures are visible around the craniotomy margins, holding the reflected dura in place.
Panel B - Cross-Sectional Schematic
This layered diagram shows how the scalp layers are rearranged from superficial (top) to deep (bottom):
| Layer | Description |
|---|---|
| Skin | Outermost scalp layer, kept intact |
| TM (Temporalis Muscle) | Mobilized through the bone window; provides blood-forming tissue |
| STA (Superficial Temporal Artery) | The key donor vessel, dips through the bone and dural openings to lie directly on the brain |
| Bone | Skull with a craniotomy window allowing tissue passage |
| Dura | Incised/opened to allow direct tissue-to-brain contact |
| Brain | The ischemic cerebral cortex, which will grow new collaterals from the overlying tissue |
Clinical Context
- Disease: Moyamoya disease - a progressive steno-occlusive disease of the internal carotid and proximal middle cerebral arteries, causing ischemic strokes (especially in children).
- Purpose of EDAMS: By laying vascularized tissue on the brain surface, growth factors (e.g., VEGF) from the ischemic brain stimulate angiogenesis from the donor tissue, forming new collateral channels.
- EDAMS vs. EDAS: EDAS (Encephaloduroarteriosynangiosis) uses only the STA + dura. EDAMS adds the temporalis muscle (M = Myo), providing richer vascular supply.
- Outcome: Collateral formation typically takes 3-6 months, confirmed on follow-up angiography.
The slide panel thumbnails on the left suggest this is part of a larger lecture series on Moyamoya surgical techniques, including STA-MCA bypass (direct method) and EMS (Encephalomyosynangiosis).
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Explain in detail
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Finding Sources
This is Slide 28 from a Moyamoya disease surgical lecture, covering a specialized variant procedure called EDAS + Encephalogaleosynangiosis. Here is a full breakdown:
Procedure Name: EDAS + Encephalogaleosynangiosis
This combines two indirect revascularization techniques specifically designed to bring new blood supply to the medial frontal lobe - territory supplied by the Anterior Cerebral Artery (ACA) - which is typically not reached by standard EDAS (which targets the MCA territory on the lateral convexity).
Why This Variant is Needed
Standard EDAS lays the STA on the lateral surface of the brain, improving collaterals in the MCA territory. However, in Moyamoya disease, the ACA territory (the medial/inner surfaces of the frontal lobes) is also frequently ischemic. To reach this area, surgeons need to access the interhemispheric fissure - the deep midline cleft between the two hemispheres. This requires a completely different approach: a bifrontal craniotomy crossing the midline.
Key Surgical Steps (from the slide notes)
1. Goal
- "↑ Collaterals in ACA territory" - The primary aim is to generate new collateral blood vessels specifically in the anterior cerebral artery distribution (medial frontal lobe), not just the MCA territory.
2. Scalp Incision (Diagram A)
- A coronal (bicoronal) scalp incision is made across the top of the head.
- Positioned 2-3 cm anterior to the coronal suture (the natural suture line between the frontal and parietal bones).
- This allows bilateral access to both frontal lobes simultaneously.
- The dashed midline in the diagram shows the sagittal midline - the incision crosses it bilaterally.
3. Large Bifrontal Craniotomy (4-8 cm) Crossing the SSS
- A large bifrontal bone flap is elevated, spanning 4 to 8 cm in width.
- Critically, it crosses the Superior Sagittal Sinus (SSS) - the large midline venous channel running along the top of the brain inside the dura.
- This is technically demanding because the SSS must be carefully protected during bone removal; injuring it causes catastrophic venous hemorrhage.
- The wide craniotomy gives access to the interhemispheric fissure on both sides of the midline.
4. Dura Opened on Both Sides (Diagram B)
- The dura mater is opened bilaterally (on both the left and right sides) while carefully preserving the Superior Sagittal Sinus in the center.
- This exposes the interhemispheric fissure - the deep space between the two frontal lobes.
- The Falx cerebri (the vertical dural fold separating the hemispheres) is visible in Diagram B running downward from the SSS.
5. The Encephalogaleosynangiosis Component (Diagram B)
- A galeal flap (a vascularized layer of the scalp composed of the galea aponeurotica - the tough fibromuscular layer just beneath the skin) is harvested.
- This flap is mobilized and tucked into the interhemispheric fissure, placed directly against the medial surface of both frontal lobes.
- The galea carries a rich blood supply from branches of the STA and supraorbital/supratrochlear arteries.
- Over weeks to months, this vascularized tissue stimulates neoangiogenesis - new collateral vessels grow from the galeal flap into the ischemic medial frontal brain.
Anatomical Structures in Diagram B
| Structure | Role |
|---|---|
| Superior Sagittal Sinus (SSS) | Major midline venous drainage - preserved and protected throughout |
| Falx cerebri | Dural fold separating the two hemispheres; must be navigated around |
| Dura | Opened bilaterally to expose the interhemispheric space |
| Galeal flap | The vascularized tissue graft placed into the fissure |
| Interhemispheric fissure | The deep cleft between hemispheres where the flap is placed |
Summary: How It All Fits Together
| Feature | Standard EDAS | EDAS + Encephalogaleosynangiosis |
|---|---|---|
| Target territory | MCA (lateral convexity) | ACA (medial frontal lobe) |
| Tissue used | STA + dura | STA + galeal flap |
| Approach | Temporal craniotomy | Bifrontal craniotomy crossing SSS |
| Fissure accessed | Sylvian fissure | Interhemispheric fissure |
| SSS involvement | No | Yes - must be preserved |
This procedure is technically more demanding than standard EDAS due to the proximity of the Superior Sagittal Sinus and the need to navigate the interhemispheric fissure, but it addresses a critical gap in coverage for patients with ACA territory ischemia in Moyamoya disease.
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Explain in flow chart
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Here is the full procedure explained as a step-by-step flowchart:
Omental Transplantation - Surgical Flowchart
┌─────────────────────────────────────────────────────────┐
│ INDICATION: Moyamoya / Cerebral Ischemia │
│ (need for indirect revascularization to the brain) │
└───────────────────────┬─────────────────────────────────┘
│
▼
┌─────────────────────────────────────────────────────────┐
│ STEP 1: HARVEST THE OMENTUM │
│ (Abdominal Phase) │
│ │
│ • Laparotomy (open abdomen) or laparoscopic access │
│ • Identify the GREATER OMENTUM │
│ (the large fatty apron hanging from the stomach) │
│ • Note its vascular supply: │
│ - Splenic artery (left side) │
│ - Celiac axis (central) │
│ - Common hepatic artery │
│ - Gastroduodenal artery │
│ - RIGHT GASTROEPIPLOIC ARTERY (main pedicle) │
└───────────────────────┬─────────────────────────────────┘
│
▼
┌─────────────────────────────────────────────────────────┐
│ STEP 2: MOBILIZE THE OMENTAL PEDICLE │
│ (Panel b → Panel c) │
│ │
│ • Detach omentum from the transverse colon │
│ • Divide short gastric vessels on the LEFT side │
│ • Preserve the RIGHT gastroepiploic artery │
│ as the dominant blood supply pedicle │
│ • Elongate/lengthen the omentum by dividing │
│ it into a long pedicle flap (panel c diagram) │
│ • The omentum is now a long, vascularized │
│ ribbon still attached to its feeding artery │
└───────────────────────┬─────────────────────────────────┘
│
▼
┌─────────────────────────────────────────────────────────┐
│ STEP 3: TUNNEL THE OMENTUM TO THE HEAD │
│ (Panel e - intraoperative photo) │
│ │
│ • Create a subcutaneous tunnel from abdomen → scalp │
│ running under the skin of the chest and neck │
│ • The omental pedicle is passed through this tunnel │
│ (photo shows the omentum being drawn upward) │
│ • Omentum must reach the craniotomy site │
│ WITHOUT tension or kinking │
│ • Pedicle length and vessel caliber are critical │
└───────────────────────┬─────────────────────────────────┘
│
▼
┌─────────────────────────────────────────────────────────┐
│ STEP 4: CRANIOTOMY + DURAL OPENING │
│ │
│ • Perform craniotomy over the ischemic brain region │
│ • Open the dura mater │
│ • Expose the cortical surface of the brain │
└───────────────────────┬─────────────────────────────────┘
│
▼
┌─────────────────────────────────────────────────────────┐
│ STEP 5: PLACE OMENTUM ON BRAIN SURFACE │
│ (Panel f) │
│ │
│ • Spread the omental flap directly over the │
│ exposed cerebral cortex │
│ • The Left gastroepiploic artery branch │
│ (shown in panel f) supplies the distal omentum │
│ • Omentum is sutured to the dural edges │
│ to hold it in contact with the brain surface │
│ • Dura may be closed over or around it │
└───────────────────────┬─────────────────────────────────┘
│
▼
┌─────────────────────────────────────────────────────────┐
│ STEP 6: CLOSURE │
│ │
│ • Bone flap replaced and secured │
│ • Scalp and abdominal wounds closed in layers │
│ • Pedicle vessel continuity preserved throughout │
└───────────────────────┬─────────────────────────────────┘
│
▼
┌─────────────────────────────────────────────────────────┐
│ RESULT: NEOANGIOGENESIS (over 3-6 months) │
│ │
│ • Omentum is rich in: │
│ - Angiogenic growth factors (VEGF, FGF) │
│ - Lymphatic vessels │
│ - Immune cells │
│ • New collateral vessels grow FROM the omentum │
│ INTO the ischemic brain │
│ • Gradually improves cerebral perfusion │
│ • Confirmed on follow-up angiography/MRI perfusion │
└─────────────────────────────────────────────────────────┘
What Each Panel Shows
| Panel | What it illustrates |
|---|---|
| b | Anatomy of the greater omentum attached to the stomach, with all supplying vessels labeled (splenic a., gastroduodenal a., etc.) |
| c | The omentum after mobilization - pedicled on the right gastroepiploic artery, elongated into a flap ready for tunneling |
| e | Intraoperative photo of the omental pedicle being pulled through the subcutaneous tunnel up to the head |
| f | Final placement - the vascularized omental flap spread over the brain surface, with the left gastroepiploic artery visible supplying the distal portion |
Key Advantage Over Other Indirect Methods
Omental transplantation provides a larger volume of vascularized tissue than EDAS or EDAMS, covering a wider cortical surface area. The omentum's natural richness in angiogenic factors makes it a powerful stimulus for new vessel growth - particularly useful in adult Moyamoya or cases where scalp vessels are inadequate for other indirect techniques.
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