STUDY DESIGN An experimental animal study. OBJECTIVE The aim of this study was to investigate the effect of pulsed electromagnetic fields (PEMF) on recovery of sensorimotor function in a rodent model of disc herniation (DH).
SUMMARY OF BACKGROUND DATA Radiculopathy associated with DH is mediated by proinflammatory cytokines.
Although we have demonstrated the anti-inflammatory effects of
PEMF on various tissues, we have not investigated the potential therapeutic effect of PEMF on radiculopathy resulting from DH.
METHODS
Nineteen rats were divided into three groups: positive control (PC; left L4 nerve ligation) (n = 6), DH alone (DH; exposure of left L4 dorsal root ganglion [DRG] to harvested nucleus pulposus and DRG displacement) (n = 6), and DH + PEMF (n = 7).
Rodents from the DH + PEMF group were exposed to PEMF immediately postoperatively and for 3 hours/day until the end of the study. Sensory function was assessed via paw withdrawal thresholds to non-noxious stimuli preoperatively and 1 and 3 days postoperatively, and every 7 days thereafter until 7 weeks after surgery.
Motor function was assessed via treadmill analysis preoperatively and weekly starting 7 days following surgery until 7 weeks following surgery.
RESULTS
All groups demonstrated marked increases in the left hindlimb response threshold postoperatively.
However, 1 week following surgery, there was a significant effect of condition on left hindlimb withdrawal thresholds (one-way analysis of variance: F = 3.82, df = 2, P = 0.044) where a more rapid recovery to baseline threshold was evident for DH + PEMF compared to PC and DH alone. All groups demonstrated gait disturbance postoperatively. However, DH + PEMF rodents were able to regain baseline gait speeds before DH and PC rodents. When comparing gait parameters, DH + PEMF showed consistently less impairment postoperatively suggesting that PEMF treatment was associated with less severe gait disturbance.
CONCLUSION
These data demonstrate that
PEMF accelerates sensorimotor recovery in a rodent model of DH, suggesting that PEMF may be reasonable to evaluate for the clinical management of patients with herniation-associated radiculopathy.
