+ Aspiration for lens implant

Aspiration for Lens implant

Aspiration is the removal of neural tissue, in this case  the 1-2 mm of tissue of the endoscope lens implant to reduce pressure and thus damage on the neural tissue, which can impact imaging quality. 

Materials:

Vacuum pump 

Aspiration pump system

3-5 30g blunt needles

Large trephine 

2-3 3ml syringes of cold saline

Aspiration pump system:

Note: Prior to the start of surgery 2-3 3ml syringes of saline should be placed in the refrigerator or freeze so that they are cold and ready for the surgery

After the bone screw has been placed and the craniotomy preformed the aspiration can begin 

1. Aspiration should be done 500um  medial to the viral injection site.  to prevent imaging any damage induced by the virus injection. 

2. Make sure all dura and bone matter has been removed to prevent clogging of the pump. 

3.  Before beginning turn on the pump system and check that it works by attempting to suck up some sterile saline, Important: Large immediate changes in the volume of saline being pulled through the needle should not be visible to the eye, this indicates the pressure is too high. 

4. Keep a ever constant flow of saline and slowly use the aspirator to remove the cortex above the hippocampus Continue removing cortex until you reach the white striations of the corpus callosum. 

5. Slowly and carefully remove the horizontal white striations of the corpus callosum until you reach the striations that go vertical.

 Example image of vertical striations of the corpus callosum  Source: miniscope.org 

6. When you reach these striations stop aspirating and clean up the sides of the crainotomy.

7. Important: Continue washing with saline until all bleeding stops and keep the brain constantly flushed with cortex buffer.

8. The miniscope.org website and Resendez et al. 2016 have different instructions on how to perform the lens implant and in addition differ in other ways.

At the end of surgery the dose of dexamethasone should be given to help with pain management and reduce the chance of blood occluding the lens. 

Amoxicillin should also be given for 7 days post surgery  

References: 

Video footage of aspirations  can be found on the surgery powerpoint presentation from miniscope.org

Notes and tips on aspirations can be found on the surgery protocol page of miniscope.org 

Resendez, S. L., Jennings, J. H., Ung, R. L., Namboodiri, V. M., Zhou, Z. C., Otis, J. M., Nomura, H., ... Stuber, G. D. (January 01, 2016). Visualization of cortical, subcortical and deep brain neural circuit dynamics during naturalistic mammalian behavior with head-mounted microscopes and chronically implanted lenses. Nature Protocols, 11, 3, 566-97

Picture from our very own Nishell Savory