Trial of Pulsed Radiofrequency for Sciatica and Disc Herniation (PRATS)

Transforaminal epidural injection of treatments, commonly steroids (TFESI), is offered to people with sciatica and might improve symptoms, reduce disability and speed up return to normal activities (NICE guidelines) Imaging-guided TFESI has traditionally been performed in the sciatica context because injection is administered directly to the nerve root, which relieves the pain markedly; however, the maintenance time is usually short. Treatment with radiofrequency for pain management is in clinical use since decades primarily with nerve lesioning (thermoablation) once the specific pain tributary nerve is identified. Pulsed radiofrequency (PRF) with neuromodulation intention (not lesioning) has been shown to be effective in reducing some types of chronic pain, both degenerative and neuropathic. Pulsed radiofrequency has been also extensively used in the context of acute and subacute sciatica due to disc herniation without sufficient level of evidence. In a prospective RCT, comparing prf directed to dorsal root ganglia and Tfesi in patients with sciatica did not allow conclusions on efficacy because of limitations of the trial. In that trial, only few participants completed the study due to violation of trial protocol translating the results as not consistent. One retrospective trial, in which the use of Prf in addition to tfesi was evaluated in patients with acute and subacute sciatica, demonstrated rapid pain relief onset and prolonged maintenance; the overall efficacy was superior to that of the single method treatment (either tfsei or prf). The investigators conducted a randomized, double-blind, controlled trial (Pulsed Radiofrequency in Addition to Tfesi for Sciatica [PRATS]) to determine if PRF in addition to TFESI leads to better outcomes in the management of patients with acute and subacute sciatica due to disc herniation, compared to TFESI alone.

The investigators conducted a multicenter, prospective, randomized trial among patients with at least 6 weeks of sciatic pain to determine whether a strategy of PRF in addition to TFESI leads to better outcomes during the first year than does a strategy of TFESI only means for sciatica treatment. Eligible patients were 18 to 75 years of age, had a radiologically confirmed disk herniation, and had received a diagnosis from an attending neurologist of an incapacitating lumbosacral radicular syndrome that had lasted for at least 12 weeks. Correlation of magnetic resonance imaging (MRI) findings with symptoms was registered. Patients presenting with cauda equina syndrome, muscle paralysis, or insufficient strength to move against gravity were excluded. Other exclusion criteria were cardiac pace-maker implant, pregnancy, or severe coexisting disease. The occurrence of another episode of symptoms similar to those of the current episode during the previous 12 months, previous spine surgery and spondylolisthesis were not considered contraindications but bony stenosis. A computer-generated permuted-block scheme was used for randomization, with an unstratified variable-block size of 2 and 4. The order of blocks was also randomized with patients assigned (1:1) to PRF/TFESI (treatment) or TFESI (control). A few hours before randomization, the patients were evaluated again, and those who had recovered from their symptoms at that time were excluded from the trial.

Aseptic technique was adopted. Imaging guided (CT) catheter needle (active tip electrode) was inserted and a sensory stimulation test was carried out using an RF generator. The catheter needle was then advanced toward the DRG until the patient reported a tingling sensation and/or dysesthesia at less than 0.3V. PRF treatment was administered at 5 Hz and a 2 ms pulsed width for 10 minutes at 45V under the constraint that the electrode tip temperature not exceed 42°C. Finally, patients received 1mL lidocaine 20mg/mL mixed with 2mL dexamethasone 10mg/mL.

Aseptic technique was adopted. Imaging guided (CT) catheter needle (active tip electrode) was inserted and a sensory stimulation test was carried out using an RF generator. The catheter needle was then advanced toward the DRG until the patient reported a tingling sensation and/or dysesthesia at less than 0.3V. After 10 minutes await (as per pRF), patients received 1mL lidocaine 20mg/mL mixed with 2mL dexamethasone 10mg/mL.

Non-surgical treatment of lumbar disc herniation causing sciatica using pulsed radiofrequency (10 minutes) directed to the interested dorsal root ganglia (percutaneous technique); after radiofrequency application, using the same needle, steroid was administered (as per the control arm). The procedure was guided by CT imaging

The primary outcome was the average leg-pain intensity score over the course of the previous 1 week (on a numerical pain-rating scale from 0 to 10, with 0 indicating no pain and 10 the worst possible pain; clinically important difference, 2 points), as assessed at 1 week and 52 weeks.

extent of disability as measured on the Roland Disability Questionnaire for Sciatica (scores range from 0 to 23, with higher scores indicating greater disability; clinically important difference, 8 points), as assessed at 4 weeks, 12 weeks and 52 weeks.

extent of disability as measured on the Oswestry Disability Index (on a % scale from 0 to 100, version 2.0, MODEMS; clinically important difference, 10 points), as assessed at 4 weeks, 12 weeks and 52 weeks.

global perceived effect (post-treatment symptoms as compared with baseline, on a scale from -5 [vastly worse] to 0 [unchanged], to +5 [completely recovered])

Subjective evaluation of current condition, expressed in terms of percentage, with 0% indicating completely disappointed and 100% indicating completely satisfied

Inclusion Criteria: Eligible patients had radiologically confirmed disk herniation, and had received a diagnosis from an attending neurologist of an incapacitating lumbosacral radicular syndrome that had lasted for at least 12 weeks. Correlation of magnetic resonance imaging (MRI) findings with symptoms was required. The occurrence of another episode of symptoms similar to those of the current episode during the previous 12 months were not considered contraindications Exclusion Criteria: Patients presenting with previous spine surgery, spondylolisthesis, cauda equina syndrome, muscle paralysis, or insufficient strength to move against gravity were excluded. Vertebral canal stenosis Other exclusion criteria were cardiac pace-maker implant, pregnancy, or severe coexisting disease.