Epidural fibrosis has been considered to be enough of a concern to spine surgeons that its prevention has been a subject of concern since the early 1900s when Lexer (Lexer E: Die Freien Transplantation en Pat 1, Neue Deutsche Chirurgie 26:264-545, Stuttgart: Ferdinand Enke,1919)  first reported on the use of free fat grafts for this purpose.  Many forms of fat including pedicled grafts and a host of biocompatible materials have continued to be tested.  Mayfield, in 1980, documented his 16 years of clinical experience with fat grafts and noted that they could prevent "constricting cicatrix" as well as serve to control cerebro-spinal fluid leaks and in the repair of dural tears.  He also noted that their greatest danger was the possibility of their acting as a space occupying lesion and causing neural compression (Mayfield FH: Autologous Fat Transplants for the Protection and Repair of the Spinal Dura, In Clinical Neurosurgery, Vol. 27, Baltimore: Williams and Wilkins, 1980)

Three examples of severe post-operative epidural and perineural scarring demonstrated on axial view computed tomographic scans (CT) are shown above.  In the first two cases the patient required additional surgery because of continued post-surgical spinal nerve compression. In the first case the red dot shows a residual (post-surgical) bony osteophyte continuing to produce lateral spinal stenosis.  In the second case the red dot is over a posteriorally displaced bone plug following a posterior lumbar interbody fusion with a autogenous bone plug.  In example three the red dot is over a post-operative collection of spinal fluid (pseudomeningocoele) which resulted from an intra-operative dural tear.  All three of these patients required additional "salvage" surgery.
 

Autogenous free fat grafts can be harvested from the primary incisional site or through separate buttock incisions.  Incisions should be made to avoid interrupting the cluneal nerve complex (see above).  The quality of fat is important because thick and fibrous adipose tissue is more likely to produce a mass effect. 

The center image is a axial CT scan performed 10 years after previous fat grafting.  The yellow dot is over the fat tissue which has become vascularized.  In the image to the right the yellow dots are over 3 fat graft sections placed at surgery.  It is important to place lateral fat first to act to support the dorsal fat mass.  This aids in avoiding dural sac compression.  Orientation is the same as the CT scan.

Alternative Substances In Preventing Epidural Fibrosis

The images at either side show a synovial chondroma (red dot) in a 42 year old male. This lesion is producing significant spinal cord compression.  Facet joints with effusion (yellow dots) document associated segmental dysfunction. Adcon-L was used surgically in this case specifically because of its lack of  mass effect on local structures (i.e. spinal cord).

At the present time the careful use of autogenous fat grafts of proper volume and consistency represent the procedure of choice in the majority of spine surgery cases to avoid undesired epidural fibrosis.  The only reason that free fat grafts are not used more widely appears to have to do with lack of understanding of "Pitfall Prevention">

In certain circumstances, such as indicated above, where the addition of any significant mass is undesirable the use of a biocompatible substance such as Adcon-L can be a preferred addition to the surgical procedure.  If Gliatech, or one of its industrial colleagues, were to also develop a companion product which maintained a biofriendly mass effect it might then become preferred to autogenous fat grafting.  Autogenous fat grafts have allowed a number of important surgical innovations such as in the management of arachnoidal cysts producing bone erosion and nerve compression.