Scar tissue in the epidural space occurs in many patients after open surgical procedures such as spinal fusion, laminectomy, microdiscectomy, etc. but causes severe symptoms in a smaller percentage.
Acta Radiol 1999 Nov;40(6):598-602 49 of 53 patients after microdiscectomy developed scar tissue
Neurol Res 1999;21 Suppl 1:S43-6 There is a direct correlation between persistent low back pain and extensive scar, since patients with increased amounts of scar had increased low back pain, regardless of their treatment group (p = 0.0003). (Adcon or no Adcon)
Spine 1998 Jul 1;23(13):1464-9 The amount of scar formation after lumbar discectomy seems to be related to the clinical outcome and the size of the surgical exposure
AJNR Am J Neuroradiol 1998 Jan;19(1):183-6 The postoperative lumbar spine: evaluation of epidural scar over a 1-year period. Ross JS, Obuchowski N, Zepp R The majority of our patients had no change in the amount of epidural scarring visible at enhanced MR imaging over a 1-year period after lumbar laminectomy/diskectomy
But such scar tissue can cause permanent intractable pain for patients. The scar tissue wraps around nerve roots, creates adhesive bands between spinal structures, and is very vascular which means it bleeds very easily.
Often peridural fibrosis develops after such surgeries 3-12 weeks later.
The pain pattern after surgery is often improvement for the first several weeks followed by the development of gradually worsening low back pain and pain down one or both legs, which may be worse than the pain for which surgery was originally sought. It can rarely cause loss of bowel or bladder control.
Patients with peridural fibrosis find that bending forwards often makes their pain worse as does lifting. Repeated injuries to the surrounding nerve tissue with internal spinal microvessel bleeding is common resulting in an undulant waxing and waning of pain symptoms over time.
Prevention is by use of a barrier gel (Adcon-L) during open surgical procedures or by avoidance of open surgical procedures altogether through use of minimally invasive spine surgery procedures such as LASE, coblation nucleoplasty, etc.
The diagnosis is made through use of epiduroscopy, epidurography, and/or MRI with gadolinium IV contrast.
Treatment is with pain medications, attempted reduction in scar tissue density via the Racz procedure or epiduroscopy(adhesiolysis), laser epiduroscopy, or neuromodulation techniques such as spinal cord stimulation, dorsal root ganglion stimulation, intrathecal infusion pump therapy. Re-operation to free scar tissue often results in still more scar tissue.