Persistence of pain after spine surgery has been called by different names such as failed back surgery syndrome, postlaminectomy syndrome or simply failed back syndrome. It does not represent failure of surgery; it represents a cluster of syndromes following spine surgery wherein the expectations of the patient and surgeon are not met. Pain may persist, increase, may change its character and may spread to a new area. Persistent pain following spine surgery is common after discectomy, laminectomy, decompression, spinal fusions and minimally invasive surgical treatment.
Reasons for this failure are:
1)Dural fibrosis,
2)Arachnoidal adhesions,
3)Muscle & fascial fibrosis,
4) Mechanical instability resulting from the partial removal of bony and ligamentous structures required for surgical exposure and decompression,
5) presence of neuropathy,
6)Acquired stenosis,
7)Adjacent segment degeneration,
8)Internal disc disruption,
9)Recurrent disc herniation,
10)Retained disc fragment,
11)Facet joint pain,
12)Sacroiliac joint pain,
13)Discitis and
14)Arachnoiditis.
In the animal models the following pathological changes are found in post laminectomy syndrome:
1)Paraspinous muscle spasms,
2)Tail contractures,
3)Behavioral pain behaviors,
4)Tactile allodynia,
5)Epidural and perineural scarring, and
6)Nerve root adherence to the underlying disc and pedicle.
Among these etiologies epidural fibrosis (20% to 36%), facet joint dysfunction (8% to 16%), sacroiliac joint dysfunction (upto 35% in spinal fusion surgeries), internal disc disruption, recurrent disc herniation, and spinal stenosis are very common and can be treated by interventional pain management procedures.
Among the various interventional pain management procedures based on probable etiologies, the following are commonly done:
1) Epidural Adhesionolysis for epidural fibrosis,
2) Facet joint block or Radio frequency medial branch rhizotomy for facet joint dysfunction,
3) Sacroiliac joint block or Radio frequency rhizotomy for sacroiliac joint dysfunction,
4) Nerve root block for persistent radiculopathy
5) Ozone nucleolysis for recurrent or persistent herniation, spinal stenosis.
But in many cases all these procedures may prove unsuccessful for long-term relief and spinal cord stimulation may prove beneficial and cost effective in the long run.