Asleep DBS

Walk into room
Anesthesia does their thing
Retape eyes with tegaderm
Turn bed 90 degrees so head is facing ceretom
Pin with doro frame (radiolucent head holder) - shoulders may get in the way - pad shoulders with foam
Fix Mayfield on inner side of head holder
Bottom of Mayfield has to be angled back towards patient's feet - if its angled forward, it will hit CT scanner and you won't be able to get entire head in scan
Shave head
Prep with chloraprep then chlorhexidine then alcohol
Put in 5 fidicuial screws - 2 frontal, 1 left posterior (above/behind L ear), 2 right posterior (one by bregma, one above/behind R ear), roughly in a circle - bias screw 3 (posterior L screw) medial to allow for tunneling
CT scan
Put suction-cup registration device on head, non-sterile registration of fiducial screws with blue thing
Use stealth to determine optimal entry points
Mark entry holes with pen. Draw upside down U-shaped incision lines approx 1 cm radius around point
Prep again
Hand drill to mark entry points
Drape - body drape, 4 drapes in square on head - include fiducial screws in field. Ioban.
Incision
dissection between galea and periostium around incision and in flap. Or subperiosteal. depends on who you ask.
Hemostasis
On L side, dissect posteriorly to form pocket
Burr holes
Hemostasis
Screw in stimlock - do not strip screws - screws on both side, slit pointing down
Screw in base - two screws that are closer together approx 10 o'clock and 2 o'clock, the one pointing down at 6 o'clock. do not strip screws. Base has to be tight, all things are registered off base.
Make sure clip fits
Attach dome
Attach other registration device to left dome.
put steatlh probe into dome, find optimal trajectory and depth. tell scrub tech so they can set the cannula.
Attach nexdrive micropositioner
Then put in cannula
Figure out where it will enter dura. Bipolar dura at that point. a lot. Cruciate incision with 11-blade
Attempt to pass cannula - if any resistance, bipolar + 11 blade again. you need to get through Pia.
push in cannula to pre-determined depth into center hole
remove stylet
Place extender
Pass electrodes
remove cannula
apply clip to base of electrode
mark electrode where its coming out of the clip
Tisseal into burr hole
CT scan - merge with preop MRI with plan. deviation of <2mm is acceptable. More requires electrode replacement
Remove everything
close - do not hit the electrode with your needle. electrode is very sensitive and fragile.

DBS generator

pocket - incision 1 finger breath below clavicle approx 5-6 cm long. Cut down until you get deep to fascia into fat layer but above muscle, make a pocket deep enough to fit finger to knuckle.

ear incision - far down enough to be over the curve of skull (sucks to tunnel over the curve), but high up enough to access leads. bovie to bone. Look up to find leads, flip them out. use heavy scissors to start tunneling process to get through neck fascia, open them, then pull them back out. LEFT lead has tie on it. Use tunneler to get to pocket. go above the clavicle. anesthesia gets upset if you tunnel into subclavian artery. screw extension leads onto tunneler and pull back to incision (L and R extension leads are the same).

connect extension leads to head leads-- white = right, blue = left. Starting with left, remove plastic coverings off head lead, wipe lead with blood, put raytech below for clean field, put new clear plastic covering thingy on (skinny side first) connect extension lead on; when you screw the leads on, you must hold the lead by contact 1 tightly  (i.e. provide counter-torque) otherwise you risk breaking the electrode. if you break the electrode, you're fired. screw to 1 click of tightness. Repeat with right electrode - only use white covering instead of clear.

connect leads to generator (for medtronic, left is contacts 1-7, right is 8-15, left goes in front, right in back, front is the brand name side). screw to 3 clicks of tightness. tuck generator into pocket, rep checks impedance. very high impedance = suboptimal contact between electrode contacts. very low = concern for short circuit i.e. electrode breakage. If all goes well, pull the electrodes straight. close pocket and head.


DBS generator replacement

Knife through skin, then continue with knife while feeling with your fingers. the only way you screw this up is by cutting the leads. cut towards the generator. Cut through capsule with knife, make sure to turn the corners around both edges. Pull out generator with kocher. unscrew/remove leads one at a time! front/left lead first. correction, the other way you screw this up is by mixing up L and R leads. Connect leads to new generator first left, then right - put the leads all the way in, make sure good contact, screw to 3 clicks of tightness. put generator back into pocket, brand name side up. Test generator to check impedances. If good, anchor with non-absorable suture if needed, close.