REPETITIVE TRANSCRANIAL MAGNETIC STIMULATION FOR FAILED BACK SURGERY SYNDROME

EFFECTIVENESS OF REPETITIVE TRANSCRANIAL MAGNETIC STIMULATION IN PATIENTS WITH FAILED BACK SURGERY SYNDROME A DOUBLE-BLINDED, RANDOMISED, PLACEBO CONTROLLED TRIAL

Failed back surgery syndrome (FBSS) is the term of persistent back and/or leg pain after surgery for lumbar disk herniation (LDH). Repetitive transcranial magnetic stimulation (r-TMS) is a technique that allows non-invasive and relatively painless stimulation of cerebral cortex. It can reduce the experience of chronic pain by using magnetic field to produce small electrical currents in the cortex.The aim of this study is to determine the effectiveness of r-TMS treatment on patients with FBSS.

Methods: In this double-blinded, randomized, placebo-controlled trial, 20 patients (aged 34-65 years) clinically diagnosed as FBSS, who had a history of surgery for LDH with persistent back and leg pain. Patients in r-TMS group received 5 Hz of r-TMS, as a 20-min (1000 pulses) daily session, 5 days per weeks, for a total of 10 sessions. R-TMS applied with MagVenture device (MagPro X100, Denmark, 2009) and figure eight coil (MMC 140 parabolic, MagVenture). Control group received sham r-TMS with the same protocol. Patients were assessed at baseline,after 5th and 10th sessions and 1 and 3 months after treatment. Visual Analogue Scale (VAS), DN-4 (Douleur Neuropathique-4 Questionnaire), Oswestry Disability Index (ODI), Beck Depression Inventory (BDI), Pittsburgh Sleep Quality Index (PSQI) were used for evaluation.

Patients in r-TMS group received r-TMS 20-min (1000 pulses) daily session, 5 days per weeks, for a total of 10 sessions.

Patients in r-TMS group received 5 Hz of r-TMS. R-TMS applied with MagVenture device (MagPro X100, Denmark, 2009) and figure eight coil (MMC 140 parabolic, MagVenture).

All groups were evaluated for low back and leg pain with Visual Analogue Scale (VAS) for rest, activity, and sleep-disturbing. Patients were instructed to indicate the severity of pain on a 10- point scale, on which 0 meant no pain, 5 meant moderate pain, and 10 meant intolerable pain.

Functional status in all groups was evaluated with the Oswestry disability index (ODI). The ODI consists of 10 topics concerning pain, lifting, ability of selfcare, ability to walk, sit, stand and travel, social life, and sleep quality and is intended to assess disability and quality of life related to low back pain. ODI scores range from 0 (no disability) to 100 (maximum disability possible).

To evaluate the subjective amount of sleep, we used The Pittsburgh Sleep Quality Index (PSQI). The PSQI evaluates the sleep quality of the previous month, and it is clinically useful in the evaluation of several sleep disorders that affect sleep quality. It includes 19 self-administered questions and 5 questions to be answered by bedroom companions.

Inclusion Criteria: Aged 34-65 years Clinically diagnosed as FBSS History of surgery for LDH with persistent back and leg pain Patients with no root compression in postoperative magnetic resonance imaging of lumbar spine Exclusion Criteria: Epilepsy Stroke Head trauma History of intracranial operation Cardiac pacemaker Pregnancy Postoperative lumbar root compression Neurologic deficits Prior physiotherapy for low back pain last 6 month

Patients in r-TMS group received 5 Hz of r-TMS, as a 20-min (1000 pulses) daily session, 5 days per weeks, for a total of 10 sessions. R-TMS was applied with MagVenture device (MagPro X100, Denmark, 2009) and figure eight coil (MMC 140 parabolic, MagVenture). Control group received sham r-TMS with the same protocol. Lumbar isometric exercises were given to all patients in both groups. Outcome measures were visual analogue scale (VAS) for rest, activity, and sleep-disturbing; Oswestry disability index; DN4-interview questionnaire; Pittsburgh Sleep Quality Index; Beck Depression Inventory (BDI). All patients were assessed at baseline, 5th session, 10th session, 1st and 3rd months after session.