Background: The epidural lysis of adhesions (ELOA) procedure supposedly has a biomechanical
component in addition to the targeted injection of medications into the epidural space. It is assumed
that the catheters used for the ELOA procedure can release epidural scars and adhesions.
Objectives: To evaluate the possible biomechanical effects of the typically used catheters and to put
these effects into clinical perspective.
Study Design: Experimental study.
Setting: The biomechanical laboratory of an academic orthopedic surgery department.
Methods: Experimental setups were devised that allow for the measurement of the 3 main forces
that can be exerted by manipulating a catheter in the epidural space or by injecting fluids through
such a catheter: axial forces, torsional forces, and hydraulic effects.
Results: The maximum axial forces measured under extremely tight catheter guidance were 7
newton (N), whereas the maximum forces under conditions that more likely reflect a real treatment
situation were between 1 and 2 N. The maximum torsional forces measured were 0.3 N under
extremely tight catheter guidance and 0.01 N under more realistic conditions. The maximum flow
that could be achieved through the typical catheter using normal saline and the maximum possible
thumb pressure onto a 5 mL or a 10 mL Luer-Lock syringe was 0.48 mL/ s. Given these results and
other data available to us, it appears impossible that the ELOA procedure with typically used catheters
has any relevant mechanical effect.
Limitations: Like with any experimental study, the realities of an in vivo situation can only be
modeled to a limited degree. The main limitation of our study is that we cannot calculate, measure,
or simulate neither the flow resistance between an epidural adhesion pocket and the open, local
epidural space nor the flow resistance between the open, local epidural space and the larger epidural
space as well as the retroperitoneal space.
Conclusions: According to our findings and arguments, the ELOA procedure is predominantly a
method for the highly targeted application of epidural medications and possibly also has a lavage
effect. A mechanical lysis of scars or adhesions appears unlikely.
Key words: epidural lysis of adhesions, epidural neurolysis, epidural neuroplasty, biomechanical,
experimental, epidural, catheter, back pain, sciatica
Experimental Study on Flow Resistance Characteristic of Corrugated Low Finned Tubes
