Microdiscectomy – Posterior Lumbar

Anesthesia Implications

Position: Prone, arms extended and flexed (“superman”)
Time: 1-2 hours (average)
Blood Loss: Low (10-50 ml)
Post-op Pain: Moderate (3-6)
Maintenance Paralytic: Ask surgeon

Keep the patient motionless – If muscle relaxants are not contraindicated, use them. Any movement could result in a CSF leak, major blood loss, nerve root injury, post-op instability, and/or injury to retroperitoneal structures.

Keep the patient normothermic – Should have the patient prewarmed and potentially heat the room. Preparation after induction can take quite a bit of time, so the patient can be hypothermic by the time the surgery is started.

Fast closing – these procedures close up quickly. Pay close attention and/or use a technique that allows a quick wake-up.

Neuromonitoring – not typically done on these cases. Cervical discectomies will often call for neuromonitoring, but several surgeons agree it is not necessary in the lumbar spine. If the surgeon does ask for it, a TIVA + 1/2 MAC of gas is a likely anesthetic technique after induction (common combination is propofol 25-150mcg/kg/min, remifentanil 0.1mg/kg).

Prone Position (general considerations): Maintain cervical neutrality. Keep IV’s out of the antecubital space. The patients arms are typically flexed, which will kink the IV. Eye protection should be used as the prone position heightens the risk of corneal abrasion and/or traction on the globe (which can result in blindness). Check the patients eyes/ears/nose regularly throughout the case to ensure they are free of pressure. Positioning of the leads is typically high on the posterior and posterolateral back (somewhere free of pressure and out of surgical borders). Keep your connections and tubing where you’ll have fast access.

Microdiscectomies are “minimally invasive” versions of the typical discectomy. Traditional discectomies result in comparably more tissue and nerve damage than microdiscectomies.

Microdiscectomies will normally omit the removal of any bone. The surgery is performed on younger/healthier patients where deformity, tumor, or infection have not complicated the presenting problem.

Fluoroscopy is performed after landmarks have been drawn and an instrument (sometimes a spinal needle) is placed over the proposed area for reference in the image. Once the correct level is found, local anesthetic is administered and incision is made down to the ligamentum flavum. A microscope is then utilized to remove the ligamentum flavum and the extruded disc.