Transforaminal Epidural Platelet Rich Plasma Versus Epidural Steroid Injection for Lumbosacral Radicular Pain: a Randomized Controlled Trial

Procedures:

Preparation of PRP The handling of and preparation of PRP will be performed under sterile conditions in the operating theatre of Queen Mary Hospital, Hong Kong, China. The SmartPReP Platelet Concentrate System (Harvest Terumo BCT) will be used and delivers a concentration of platelets and growth factors that is roughly 4-6 times greater than that found in whole blood. The separation process produces a white blood cell (WBC) composition that contains 100% more mononuclear (lymphocytes and monocytes) cells while reducing the granulocyte cells by 60%. Two millilitres of anticoagulant citrate solution will be first added into the smaller chamber of a two-chamber APC (Autologous Platelet Concentrate, Harvest Terumo BCT) kit. Fifty-four milli-litres of autologous venous blood will be drawn under aseptic technique from the cephalic or basilic vein of each patient's upper limb and collected in a sterile 60 cc syringe that contains 6 ml of anticoagulant citrate solution. The total volume of 60ml consisting of blood sample and citrate solution will be transferred to the larger chamber (blood chamber) of the APC kit. The APC kit will be loaded in the SmartPRep2 centrifuge machine. Centrifuge spinning procedures will be followed by standard two-stage centrifugation spinning. The first cycle will take three minutes at 2500 ± 150 rpm and the second cycle will take nine minutes at 2300 ±140 rpm. After processing, the syringe with the spacer will be used to withdraw and discard the platelet poor plasma layer. Seven milli-litres of PRP will finally collected for injections. For patients in the ESI group, the blood will be discarded. These will be done after the patient is placed in the prone position to maintain patient blinding.

Epidural injection All epidural injections will be performed under aseptic techniques using fluoroscopic guidance. A specialist pain fellow accredited by the Hong Kong College of Anaesthesiologists will either conduct or supervise the performance of epidural steroid or PRP injection. Epidural injection will be performed under aseptic technique in the operating theatre. Standard monitoring will be applied and patients will receive light sedation using target-controlled infusion (TCI) of propofol with an effect site concentration of titrated between 0.5-1.5mcg/ml.

The lumbosacral level selected for injection will be based on symptoms and imaging findings. The image intensifier will be adjusted to obtain an oblique view. A single level, unilateral epidural injection will be performed. For the transforaminal epidural injection, a 22-gauge spinal needle will be inserted coaxially via a subpedicular approach to target the upper part of the foramen under fluoroscopic guidance. Correct needle position will be confirmed with appropriate contrast spread (1ml of contrast) in the anteroposterior, oblique, and lateral view. Spread of contrast delineating the nerve root together with proximal epidural spread will be accepted as indicating correct needle position. A single level injection will be performed because there are no clinical trials showing that multilevel injections is superior to single level injection, and a well-positioned injection usually spreads to multiple levels, thus achieving the effect of multi-level injection. 2ml of 1% lignocaine will be given for skin infiltration. Once correct position is confirmed, drug injectate will be administered. For the ESI group, 8mg of dexamethasone (4mg/ml) added to 1 ml of normal saline will be given (total 3ml volume). For the EPRP group, 3 ml of PRP will be injected. The total volume of injectate for both groups of patients is 3ml.

Blinding will be assessed immediately after epidural injection using the James blinding index and Bing blinding index.