Making the EMG electrodes:

PFA-Coated Stainless Steel, 7 Strands, Diameter: 0.003 in. bare, 0.0055 in. coated, Nominal AWG: 41 bare, 36 coated, 25 ft.

1. Cut 2 lengths of wire, about 10 cm each. Take one of the lengths of wire.

2. Each length of wire will have 2 ends-- one will be the connector end and will be soldered to the connector that sticks out of the implant. The other will be the lead end, and will be buried in the muscle.

3. Tie a square knot about 5 cm from the connector end

4. Under the microscope, carefully strip a 1 mm long section 1.5 mm after the knot, towards the lead end. To do this, simply tape the ends of the wire on a hard plastic surface, and gently cut horizontally along the ends of the stripped region. Then, cut vertically to remove the insulation.

5. Nick the insulation about 0.5 mm away from the lead end of the wire. During surgery, you will tie the suture to this nick to pull the electrode wire through.

6. Under the microscope, gently remove about 5 mm of insulation near the connector end

7. Attach the connector to the connector end of the wire. Hold the connector with the clamps, apply silver epoxy to the inside of the connector, coat the stripped wire with the silver epoxy, and stick the coated wire in the connector. Apply some heat to set the epoxy.

8. Repeat the steps with the second piece of wire.

9. Apply ZAP around soldered joints

Before surgery: (sanitize equipment in cetylcide overnight)

Place round-headed scissors (for enlarging subdermal space), sharp scissors (for making incision through skin under jaw), suturing clamp, space enlarger tool (for stretching out the incision to the necessary size, and trocar (made from yellow needle tips) into cetylcide. EMG electrodes should be sanitized in 70% EtOH the day of the surgery—if you do it the night before, the 5 min epoxy will come off.

Day of surgery:

Get blue surgery tray. Fill glass bottle with saline. Place the stuff in the cetylcide into the saline.

Get iodine, Altoid box, some tape (since the animal will have to be face up, it helps to position the head by placing the IOCs inside the altoid box, and stabilizing using tape.

Get ZAP, needle filled with ZIP

Get 6-0 P-3 13 mm 3/8 “reverse cutting” sutures (for threading the EMG wires through the muscle). You want thin thread here—this is why 6-0 is best.

Get 4-0 PC-3 16 mm 3/8 conventional cutting ABSORBABLE sutures for closing animal back up.

  1. Knock animal down using KX mix. Place electrodes in ethanol to disinfect.
  2. Shave under jaw and up to the implant on the side of the EMG (if you are right handed, you will find it slightly easier to implant the EMG in the left digastric, so the one closer to your right hand when the animal is facing up. However, if the electrode bundle is already on the left side, it is advisable to put the EMG on the right side. The reason is the connector sits very nicely against the “acrylic wall” of the electrode bundle. If you are to implant the EMG in the right digastric, flip the animal around so that its head is facing towards you. )
  3. Place animal on heating pad (make sure that the pad is well insulated, as burns can happen easily)
  4. Clean jaw, head area with iodine, followed by ethanol
  5. Place animal face up, head away from investigator
  6. Pinch skin up using thick tweezers, and cut about 5 -6 mm horizontally using the sharp scissors
  7. Use round headed scissors to cut away tissue under hole, and also make a cavity leading up to the side of the implant.
  8. Attach EMG connector to the implant using ZAP (this will decrease gravitational tension on the electrodes while you are trying to implant them!)
  9. Place a trocar into the subdermal cavity, and pass the electrodes through the trochar.
  10. Place space enlarger tool so that the two clamps are above and below the place of EMG insertion. Stretch/cut tissue as desired in order to get nice view of digastric. Make sure that the two electrodes are in the middle of the space enlarger tool.
  11. Tie the end of the 6-0 suture to the nicked end of one of the leads (use a double knot)
  12. Under the microscope, push the suture needle through the muscle (one is to be inserted about 1 mm from the other. Insertion must be orthogonal to the grain of the muscle). Pull until the knot hits the muscle. Do not pull the knot through the muscle.
  13. Pull the other lead through the muscle in a similar fashion.
  14. Glue the knots to the connective tissue over the masseter using vetbond. A small drop is enough!
  15. Tie the ends of the leads to each other, and attach to the connective tissue over the junction between the masseter and the digastric using vetbond. Cut off any excess length.
  16. Attach connector to implant using dental acrylic. Make sure there is enough slack in the wires between the connector and the proximal knot.
  17. Clean muscle with alcohol
  18. Close up the skin incision under the jaw (remember to try to match the skin folds up nicely against each other, with as little bunching as possible). I usually put in between 3-4 stitches.
  19. Apply bacitracin to sutured incision, also around side of implant where EMG wires exit
  20. Administer 0.08 cc meloxicam, 0.2 cc Pen-G, 0.3 cc Ringers (per hour of surgery).