Procedure for a typical run-of-the mill posterolateral disc herniation which is described as central/paracentral and location--based on the book, "Spine Surgery: A Practical Atlas." Wetzel FT, Hanley Jr. EN. McGraw-Hill publishing – 2002

#1) the patient's skin over the suspect disc  (low back ) is cleaned with an antiseptic and anesthetized with lidocaine and epinephrine.

#2) the skin is incised with the scalpel and self retaining retractors are inserted to pull it back and out of the way.

#3) the dissection process begins as a physician meticulously works his way down through subcutaneous fat, muscle and fascia only on the side of the herniation until he reaches the facets and lamina of the target vertebra. Care should be taken not to damage the capsules of the facet joint.

#4) the loose dissector muscle and fascia are pulled out of the way by a retractor. 

#5) now, depending on the level, some of the protective lamina of the vertebrae must be removed (laminotomy) in order to visualize the epidural space.  Sometimes a portion of the facet joint must also be removed (facetectomy) if the herniation is large.

#6) the final Sentinel to the epidural space must now be breached: a hole is now cut in the ligamentum flavum (or sometimes the whole ligament is removed) with a tool called a Kerrison rongeur.

#7) now the delicate and dangerous part: in order to visualize the disc herniation, the thecal sac (a.k.a. dural sac) must be medially pulled out of the way with a retractor. The nerve root must also be pulled medially.  At last, the anterior epidural space can be visualized and the disc herniations is revealed.

#8) often times the herniation is covered by a membrane which may consist of annulus fibrosis and/or the posterior longitudinal ligament. This needs to be cut in order to get at the true disc herniation/herniated nuclear material.

#9) the herniated fragment is then removed with an instrument called a pituitary rongeur.  After removal, a thorough and diligent inspection of the entire region is accomplished to ensure that no disc fragments are left behind.

#10) the retractors are released and the wound is then closed and appropriate layers. The operation is complete.

Complication Rates: complications with this procedure are rare but can include the following: transmit sensory dysesthesias (a feeling like acid under the skin or burning, wetness, itching, electric shock, and pins and needles) or recurrent disc prolapse.

In general, the risk for recurrent disc herniation is 4%-8% and is not appear to be influenced by the amount of disc resected.

FAR LATERAL DISC HERNIATION:

Lateral or far lateral disc protrusions are much less common than posterolateral protrusions. It generally occurs in older patients (60-70 years of age) and commonly involves L3 or L4 nerve root's.

CT discography (according to some studies) are the most sensitive and specific for diagnosing far lateral disc herniations provided the herniation remains in cotton annuity with the remainder of the disc.

Since this flavor of herniation is relatively uncommon, I will no longer discuss it here.