When you guys do spinal cord stimulator implants, which ligament, muscle, or fascial layer do you choose to place the anchors in hopes of minimizing lead migration? Ive been taught in fellowship to do lumbodorsal fascia but was wondering what most do that do a lot.
Also was just wondering if you guys like to enter the same space from either side of the spinous process and make a midline incision or enter in 2 adjacent spaces from the same side and make a vertical incision.
Got my first implant this week as an attending. Nervous but excited.
Thank you
Find the interlaminar space that you want to enter, the medial borders of the pedicles of the level below, and the anatomical midline. Plan on entering the fascia at approximately the level of the pedicles of the level below with the Tuohy introducer needles. Plan your incision in the midline. The entry points through the thoracolumbar fascia with the Touchy needles (after the incision has been made) should be in the cephalad third of the incision. Plan your incision length accordingly.
Infiltrate with lido+ epi then make an incision down to the underlying adipose tissue. Continue dissecting with monopolar electrocautery until the underlying thoracolumbar fascial layer is exposed. Use a blunt probe (i.e., your fingers) periodically to feel for the underlying fascial layer. It's easy to inadvertently pierce the fascial layer with electrocautery if you're not careful. Once you've reached the thoracolumbar fascia, do some blunt finger dissection initially (or with a peanut) along the fascial plane bilaterally to create a clean division between the fascia and overlying adipose tissue. You should extend the plane laterally with monopoly electrocautery. This will create some space for the tension relief loops and also make it easier to retract the skin edges laterally with a self-retaining retractor.
Once you're satisfied with the initial dissection and you have hemostasis, place a self-retaining retractor in and expose the underlying fascia. Ideally you should easily be able to palpate the lumbar spinous processes in the midline. You can proceed with accessing the dorsal epidural space with the introducer needles. I typically place one needle on one side and then place the other needle contralaterally, however I have also placed them on the same in some cases. It just depends on how things go during the case.
For anchoring, I typically place a small incision along the line of the introducer needle through the fascia, which facilitates implanting the nose of the anchor THROUGH the fascia. This helps prevent migration. I anchor the leads to the thoracolumbar fascia using non-absorbable suture, with the suture configuration dependent on the vendor. I have anchored the leads to the interspinous ligament deliberately DEEP to the thoracolumbar fascia previously. It works, but I'm not a big fan of the subperiosteal dissection required, because it tends to cause a fair amount of postoperative back pain.
SCS implants are a lot of fun. Don't be too anxious about your first case! You have the skills to do it. Don't rush through the case. You'll be fine.
