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The ligamentum flavum is only removed laterally over the nerve root if needed for identification and minimally over the lateral most aspect of the thecal sac. The limited removal of the ligamentum flavum decreases the risk of further scar tissue in the postoperative period. Next the nerve root is identified. The pedicle should also be identified allowing easy location of the intended disc. The area around the disc space is then probed. A free fragment based on the MRI results should try to be identified before incising the disc space. It is sometimes impossible to remove the herniated free fragment without first decompressing the disc space because of the large size of the herniated disc and its compression on the surrounding neuronal structures. If this is the case the disc space is incised, decompressed from below and then using whatever instrument that the surgeon prefers, the herniated disc can be decompressed down into the disc space, decreasing the chance of a dural tear or trauma to the nerve root or thecal sac. With this lateral approach, minimal to no nerve root retraction is required. After the disc space is decompressed of any free fragments, the floor of the canal, foramen and nerve root shoulder and axilla are checked for any other free fragments. Surgery is an art. The anatomy and pathology is interpreted in the surgeons mind prior to the operation and must match what is actually seen. Questions should be asked if the two do not correlate. After resection there should be good motion of the nerve root. The disc space is copiously irrigated; any additional free fragments are removed. Excellent hemostasis must be obtained at this point. It is usually the bleeding that is responsible for the postoperative scar. A piece of fat is placed in the epidural space. The lumbar dorsal fascia is closed in a watertight fashion, 1/4% plain sensorcaine is injected into the lumbar paravertebral space on the side of the operation, the wound closed in multiple layers with subcutaneous stitches, and a band-aid is used for the dressing.
In the recovery room the patient should say that they have incision pain, but complete resolution of their preoperative lower extremity radicular pain. Any paresthesia may also be gone, but this should not be expected. Furthermore, there may be tingling or light numbness in part of the area of the previous pain. It probably was there before surgery at sometime but was covered by the intense pain. The radicular pain may return in two to three days after the operation, last for about a week, and then clear as the nerve root swelling resolves. This can last up to a month in the very elderly patient who may have additional levels of degenerative disc disease and degenerative facets. The patient is ambulated in four hours after the completion of surgery, given physical therapy instructions and discharged when they are comfortable. The majority of the patients go home the same day with even more patients discharged within 23 hours.
TREATMENT RECURRENT HNP
During the first couple weeks after surgery the disk is in a vulnerable state. Although it is unusual disk herniation can re-occur at the operated level or adjacent levels. Sometimes the herniating event can be twisting, sneezing, lifting or falling. It is also possible that not the entire disk was removed. However, if the pain resolved after surgery it is unlikely that the disk was not removed. Other causes of leg pain in the early post operative period include nerve root irritation, infection, instability or causes listed previously. If the pain does not respond to conservative measures then a repeat MRI is performed. With evidence of a recurrent herniated disk the procedure
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