Epoch ECG Systems- Available from BIOPAC
Implanting an Adult Rat with the Single-Channel Epoch Transmitter forRecording EEG
November 21, 2013
Epoch ECG Systems- Available from BIOPAC
Recommended Surgical Tools
A. Scalpel handle
B. Scalpel blade (#15)
C. Fine scissors
D. Burr tool
E. Fine burr (FST #19007-09or equivalent)
F .4x Hemostats (curved)
G. Toothed forceps
H. Absorbent spears or cotton-tipped applicators
I. Needle drivers
J. Accelerant (Loctite 7452 orequivalent)
K. Cyanoacrylate (Loctite 4541or equivalent)
L. Suture (Vicryl 4-0)
M. Electrocautery unit
Epoch ECG Systems- Available from BIOPAC
Sterilize Transmitter
Ethylene Oxide• Place transmitter in Tyvek pouch
• Gas for a complete Kill cycle
• Off-gas for at least 24 hours
Isopropyl Alcohol• Soak in 70% ethanol for 1 minute
• Rinse in sterile saline
Epoch ECG Systems- Available from BIOPAC
Anesthesia
• Anesthetize animal andmaintain anesthesiaaccording to IACUC-approved protocol
Epoch ECG Systems- Available from BIOPAC
Shave Scalp
• Shave the scalp of theanimal over the skull andremove excess hair
Epoch ECG Systems- Available from BIOPAC
Fix Position in Stereotaxic frame
• Each ear bar tip must beproperly positioned inauditory meatus
• Do not excessively tightenear bars
• Make sure anesthesia nosecone is secure
• A heated water blanket orheating pad is used underthe animal to keep it warmduring surgery
• Periodically check depth ofanesthesia with cornealreflex, limb pinch, or pulseoximetery.
Epoch ECG Systems- Available from BIOPAC
Protect the Animal’s Eyes
• Apply lubricant eyeointment to each eye
• A mixture of mineral oil(20%) and whitepetrolatum (80%)
Epoch ECG Systems- Available from BIOPAC
Sterilize Incision Site
• Swab the scalp withalternating applicationsof 70% ethanol andbetadine.
• Start in the center of thescalp and makeincreasingly widerconcentric circles.
Epoch ECG Systems- Available from BIOPAC
Scalp Incision
• Incision is made slightlybehind the eyes along themidline, approximately ¾”.
• Try to make a single cut,which results in betterhealing.
Epoch ECG Systems- Available from BIOPAC
Exposing the Scalp
• Use hemostats to graspscalp.
• Gently pull scalp awayfrom midline at fourcorners.
• Look for anatomicallandmarks in the skullsuch as Bregma andLambda.
Epoch ECG Systems- Available from BIOPAC
Clean and Dry the Skull
• Remove all periosteumfrom the exposed surfaceof the skull.
• Cauterize any bleedingsections of bone.
• Skull must be completelydry.
Epoch ECG Systems- Available from BIOPAC
Drill two holes in the skull over desired electrode locations
• Recommend usingDremel-type tool with aburr-type drill bit
• Practice drilling burr holesin a block of wood beforeattempting in a rat.
• Holes should be biggerthan 300 μm in diameter.
• Burr sizes of 0.9 mmproduce clean holes.
• Alternatively, no holesneed to be drilled forstable EEG recordings.
Epoch ECG Systems- Available from BIOPAC
Check Spacing
• EEG from each electrodeis subtractive (electrode 1– electrode 2).
• Holes can be within ahemisphere or betweenhemispheres.
• Alternatively, no holesneed to be drilled forstable EEG recordings.
Epoch ECG Systems- Available from BIOPAC
Trim Electrode Leads
• Use surgical scissors totrim the electrodes to thedesired length.
Epoch ECG Systems- Available from BIOPAC
Check Electrode
• Check the fit of thetransmitter and gently bendelectrodes to line up over theintended sites for burr holes.
• Trim excess electrode
length.
Epoch ECG Systems- Available from BIOPAC
Drill Anchoring Screw Holes
• Create two additional burrholes outside of the footprintof the transmitter.
Epoch ECG Systems- Available from BIOPAC
Insert Anchoring Screws
• Use sterile self-tappingwood screws.
• Use “0” x 1/8 inch 303stainless steel screws orequivalent.
• Insert screws with sterile“jewelers” screw driver.
• Screws should be snugwith the head of the screwand one or two threadsexposed.
Epoch ECG Systems- Available from BIOPAC
Maintain a Dry Skull
• Be certain that the skull isdry before gluing thetransmitter to the skull.
Epoch ECG Systems- Available from BIOPAC
Check Fit
• Check the fit of thetransmitter.
• Electrodes should guidethrough the holes in theskull.
• Transmitter should fitbetween the twoanchoring screws.
Epoch ECG Systems- Available from BIOPAC
Apply Cyanoacrylate
• Liberally applycyanoacrylate on the baseof the transmitter aroundthe outside edge.
• Make sure to avoidcoating the electrodes
Epoch ECG Systems- Available from BIOPAC
Apply Cyanoacrylate
• Cyanoacrylate will flow tothe center of thetransmitter when placedon the skull.
Epoch ECG Systems- Available from BIOPAC
Apply to Skull
• Thoroughly dry skullbefore placing transmitterto ensure strong adhesivebond.
• Apply transmitter coatedwith cyanoacrylate to theskull.
• Take care to alignelectrodes withcorresponding burr holes.
• Try to avoid piercingmajor vascular structures.
• Hold the transmitter inplace for one minute.
Epoch ECG Systems- Available from BIOPAC
Apply Accelerant
• Apply accelerant througha syringe around thecyanoacrylate at the baseof the implantedtransmitter.
• Use accelerant sparingly,taking care not to applyto adjacent tissue.
• Cyanoacrylate accelerantis useful to speed curingof adhesive, but is notnecessary.
Epoch ECG Systems- Available from BIOPAC
Apply Additional Adhesive
• Apply additionalcyanoacrylate around thebase of the transmitter.
• Thoroughly cover bothanchoring screws.
• Push cyanoacrylate upthe sides of thetransmitter.
Epoch ECG Systems- Available from BIOPAC
Apply Accelerant
• Apply accelerant througha syringe around thecyanoacrylate at the baseof the implantedtransmitter.
• Use accelerant sparingly,taking care not to apply toadjacent tissue.
• Wash away excessaccelerant with sterilesaline.
Epoch ECG Systems- Available from BIOPAC
Suture Skin
• Suture the skin around thebase of the transmitter,but do not cover thetransmitter.
• Top of transmitter must beabove skin to efficientlytransmit neural signals.
• Skin should be reasonablytight around thetransmitter.
Epoch ECG Systems- Available from BIOPAC
Remove Animal
• Remove animal fromstereotaxic frame andplace on heated blanketfor recovery.
• A triple antibiotic can beapplied to the sutures andaround the base of thetransmitter.
• Animals should be warmand mobile beforereturning to their homecage.
Epoch ECG Systems- Available from BIOPAC
Recover Animal
• Once animal is active,moving around, andgrooming, it can bereturned to its home cage.
Epoch ECG Systems- Available from BIOPAC
Care and Housing
• Recordings maycommence directly afteranimal has recoveredfrom surgery.
• Sutures may need to beremoved from the scalpafter one week.
• Check for signs ofnecrosis around thetransmitter and treatwhere needed.