2. Background
Uses: to stop blood flow to the aneurysm
Mechanism: crushes the endothelium leading to secondary thrombosis of the
aneurysm
3. Ideal clip
1. Clamping pressure sufficient to isolate the aneurysm but not so high as to damage the
blood vessel
2. Clamping pressure constant over time to prevent displacement/slipping
3. As small as possible
4. The material nonmagnetic & low density to prevent interference with MRI/ CT
5. Should not obstruct the surgeon's view during implantation
6. Surface smooth and absent jagged edges
7. Surface free from cracks which trap foreign matter & contamination
8. Proper jaw alignment should be maintained at all times to prevent shearing of the
vascular tissue between the jaws.
4. Types
Temporary
Permanent
Standard, mini, and extra-long sizes
Straight,
curved forward, backward and sideward,
bent forward, backward and sideward, and
bayoneted.
5. Evolution
Cushing's malleable silver clips
Olivecrona: added winged flanges so that it could be removed if suboptimal
Dandy (1937) V-shaped malleable silver clip to the neck of an internal carotid artery
(ICA) aneurysm
Dandy WE: Intracranial aneurysm of internal carotid artery cured by operation. Ann Surg 107:654, 1938
Mayfield(1952) repositionable spring loaded clips
7. Evolution
There are four major clip designs that are currently available in the market
McFadden Vari-Angle
Sundt Slim-Line
Sugita
Yasargil
The mechanism of clip opening and closure is the basis for dividing clips into
U/V type
pivot
mobile fulcrum and
alpha types
8. Evolution
(a) V-type clip with an Olivecrona flange
(b) Pivot type clip with a central pivot point and external spring
(c)Mobile fulcrum clip. Blades touch each other, but do not cross at the base eg Scoville Clip.
(d)Alpha clip
9. Evolution
Spring mechanism developed by the French instrument maker Joseph Charriere (1840)
One of the most significant alterations in the basic forceps design
This design modification reversed the action of the forceps-
opening the blades when compressed and letting it close when released.
10. Evolution
Fenestrated clip
Kees made a fenestrated clip overnight when Professor Drake requested him to create a
special clip for an otherwise unclippable basilar bifurcation aneurysm
booster clips, t-bar clips, and Sundt graft clips
11. Material Science
Silver
Stainless steel alloys such as 301 SS
Phynox (Yasargil FE) High grade cobalt- chromium
Eligiloy (Sugita Standard)
In current practice, both Yasargil and Sugita clips are made of medical grade
titanium.
Ceramic clips
316MOSS, Elgiloy, Phynox, and titanium are safe to be implanted.
14. Repeated opening or sterilization of the clips does not significantly decrease
the closing forces of the aneurysm clips.
Suzuki et al Neurosurgery. 1997 Feb;40(2):318-23.A comparative study of intracranial aneurysm
clips: closing and opening forces and physical endurance
Closing force
Sugita clip Yasargil clip
Closing pressure (temporary) 0.69N (70g) 0.88-1.08N (90-110g)
Closing pressure(permanent) 1.27-1.47 N (130-150 g) 1.47-1.96 N (150-180 g)
19. Direction of clip
Rhoton's rules of aneurysm formation
(I)aneurysms arise at the branching sites on the parent artery (side branch or bifurcation)
parallel to afferent and efferent
(ii) aneurysms arise at turns or curves in the outer wall of the artery where hemodynamic stress is
the greatest
(iii) aneurysms point in the direction that blood would have gone if the curve at the aneurysm site
was not present
Parallel to parent artery for aneurysms at curves
(iv) each aneurysm is associated with a set of perforating arteries that needs to be preserved
parallel to the line of perforators across an aneurysm base
26. The perfect clip
MCA Intersecting clip
P Comm Straight clip
A Comm Straight clip/Stack/Fenestrated
Oph A Side angled Clip
Pericallosal A Straight
BA Tandem
PICA Fenestrated
27. Temporary clip; Rule or Choice?
Routine?
softens the aneurysm and makes the neck more pliable
reduces the risk of massive blood loss and obscuration of the operative field in the
event of a rupture
when the vessels are very atherosclerotic better to avoid