[Usefulness of botulinum toxin injections in the treatment of postoperative pain after cervical spine surgery: Preliminary results].

Abstract

Postoperative neck pain after cervical spinal surgery is a common occurrence, the prevalence of which can reach up to 60%. Since 2005 a prospective study, still in progress, is attempting to show the efficacy of botulinum toxin injections in its treatment.
Two hundred and fifteen patients operated on in the same institution for cervical spondylotic myelopathy were prospectively followed-up; 38 of them presented postoperative neck pain and were enrolled either in a course of botulinum toxin injections (19) or in conservative treatment (19). The muscles injected, in descending order, were: trapezius, supraspinalis, splenius capitis, and rhomboids. Injections were made using Type A-botulinum toxin (Botox*-Allergan Pharmaceuticals, Westport, Ireland), increasing from 20 to 100U Botox* without exceeding 300U once in the same patient, performed every 3 months if necessary. The conservative treatment consisted of a course of thiocolchicoside (16mg/day) and physical rehabilitation. The lordosis angle was calculated on lateral sitting radiographs in the neutral position immediately postoperatively and 1.5 months after injection and correlated to pain improvement evaluated by the visual analogic scale (VAS).
No visible improvement was found on x-rays in three patients after injection, and in 11 after conservative treatment. In 16 cases, after an average of three injections, the gain in lordosis averaged 11.3° and the VAS score was decreased by 4.6 points versus 4.7° and a decrease of 0.6 points after conservative treatment.
Regardless of its limitations, the present study would seem to show potential value in the use of botulinum toxin in the treatment of postoperative pain after cervical spinal surgery.