Aneurysm clips /clipology

aneurysm clips techniques

1. Clipology Gopal Sedain Assistant Professor Department Of Neurosurgery Institute Of Medicine

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. C lamping pressure sufficient to isolate the aneurysm but not so high as to damage the blood vessel 2. C lamping 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 . S hould not obstruct the surgeon's view during implantation 6 . S urface smooth and absent jagged edges 7 . S urface 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

6. Evolution

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 S pring mechanism developed by the French instrument maker Joseph Charriere (1840) O ne 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.

12. Making of a clip

13. Closing force

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 )

15. Evolution of Yasargil clips

16. Evolution of Yasargil clips

17. Sugita clips

18. Clip application Working line of clip appliers must be 15 to 30 degrees off the sight line of microscope

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

20. Clipping techniques

21. Clipping techniques

22. Clipping techniques

23. Clipping techniques

24. Clipping techniques

25. Re inforcing clip

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