Pre-op

This case requires C arm, not flat plate. 

You will need lead for the case. 

Indication

Persistent low back and leg pain in the absence of neural element compression on MRI. 

Anesthesia

MAC sedation. Patient will be kept asleep for needle placement then woken up to verify adequate coverage of stimulator. 

Positioning

Prone on a regular OR table, slight reverse Trendelenburg, 2 arm boards at the sides, elbows are bent, hands up, elbows at the sides.  

Slide the bed upwards to make room for the C arm to go under the expected location of the T12/L1 interlaminar space. 

Draping

Drape widely with four blue towels. Ioban in strips around the periphery. Drape with 4 block drapes.  

Clip a hemostat to the top drape on the patient's right side such that it will be in the field of view of an AP x-ray shot. 

Procedure

Raise a weal just caudal to the expected location of the T12/L1 interlaminar space with lidocaine.

Leave the local needle in the skin and take an AP shot to verify approach to the T12/L1 interlaminar space. 

Replace with the Tuohy needle and take AP shots until the needle is appropriately positioned superficial to the interlaminar space

 When you are on trajectory, withdraw the stylet and drip some sterile saline into the bore of the Touhy needle until you have a meniscus.  

Grip the shaft of the Tuohy needle below the hub and advance until the meniscus suddenly disappears due to fluid draining into the epidural space.  

Screw the syringe with sterile water in it into the Touhy needle and inject a few cc of sterile water, verifying that you are in the correct space by meeting no resistance.  

Take the trial stimulator lead and advanced through the bore of the needle until the top of the lead is at T8.  Verify with an AP shot.  

Attach the generator, wake the patient, turn on the stimulator, and verify that the patient feels a tingling sensation in the distribution of their low back or leg pain.

Withdraw the Tuohy needle, taking care not to displace the lead.  

Take a final shot to verify that the lead has not moved.  

Secure the lead to the skin with a releasing loop sewed in place with 3-0 nylon, attach the battery, and tape the battery to the flank.

Cover the whole back with an Ioban

Orders

Patients are discharged home the same day. 

Follow up with Dr. Moossy at the next week's clinic visit to remove the stimulator trial. Removal is done in the clinic. 

Patients are scheduled for permanent implantation of the SCS for the first OR day following their clinic visit. If they derive benefit from the trial, the scheduled OR date is kept. If they don't, it is cancelled. 

Complications

If you advance the needle too far and get CSF this is called a "wet tap." Continue with placement of the trial electrode as you would otherwise, knowing that there is a chance that the electrode is in the subarachnoid space. 

If the patient feels fine and the stimulator seems like it's working, proceed as usual. 

If they have intolerable pain you may have to cancel the procedure. 

If they have leakage of CSF from around the stimulator, tie a purse-string suture around the exit site and pull it tight.