Facial nerve injury in neurosurgery: a rehabilitation potential of botulinum therapy

Abstract

Surgical treatment of posterior cranial fossa and cerebellopontine angle tumors is associated with a risk of facial nerve dysfunction. The causes for facial muscle paresis include nerve compression by the tumor, destruction of the nerve structure by the tumor growing from nerve fibers, nerve injury during surgical removal of the tumor, etc. The first 3 months after facial nerve injury are a potential therapeutic window for the use of botulinum toxin type A (BTA). During this period, the drug is introduced both in the healthy side to improve the facial symmetry at rest and during mimetic movements and in the affected side to induce drug-induced ptosis. Post-paralytic syndrome develops 4-6 months after facial nerve injury. At this stage, administration of BTA is also an effective procedure; in this case, drug injections are performed on the affected side at small doses and symmetrically on the healthy side at doses doubling those for the affected side. BTA injections are mandatory in complex treatment of facial muscle paralysis.

Treadmill training of rats after sciatic nerve graft does not alter accuracy of muscle reinnervation

“…Nerve transection, however, interrupts all basal lamina tubes, leads to the mis-sprouting of axonal branches, and destroys myotopic reinnervation ( Figure 1 ) that cannot be compensated by central plasticity ( 75 ). In particular, double-labeled neurons, that were never observed in intact animals, simultaneously innervate fibers of the flexor and extensor muscles, and thus cause an antagonistic inhibition, also referred to as auto- or post-paralytic syndrome ( 3 – 6 , 24 , 27 , 28 , 76 ).…”

Botulinum Toxin a Treatment of Delayed Facial Palsy in a Randomized Trial

“…BoNT-A therapy is an effective method for the correction of mimic muscle tone, which is used in facial neuropathies of different origin [19,20]. The unilateral decrease of mimic muscle tone results in a significant increase of antagonistic muscle traction on the intact side, which leads to a constant stretching of paretic muscles [19,21].…”

“…BoNT-A therapy is an effective method for the correction of mimic muscle tone, which is used in facial neuropathies of different origin [19,20]. The unilateral decrease of mimic muscle tone results in a significant increase of antagonistic muscle traction on the intact side, which leads to a constant stretching of paretic muscles [19,21]. Based on our previous research in patients with facial nerve palsy developing after neurosurgical operations, we postulated that BoNT-A injections on the intact side-as in patients with acute facial nerve palsy-provided prolonged relaxation of the mimic muscles on the hyperactive intact side in patients with DFP.…”

“…However, the broad spectrum of adverse effects associated with GC treatment limits its use and has necessitated the search for additional highly effective and safe treatment strategies [18]. Botulinum toxin type A (BoNT-A) has demonstrated efficacy in the treatment of acute facial nerve injury after neurosurgical interventions, which allows it to be considered as a therapeutic option for DFP [19].…”