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

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

Background and purpose

After peripheral nerve lesions, surgical reconstruction facilitates axonal regeneration and motor reinnervation. However, functional recovery is impaired by aberrant reinnervation.

Materials and methods

We tested whether training therapy by treadmill exercise (9 × 250 m/week) before (run-idle), after (idle-run), or both before and after (run-run) sciatic nerve graft improves the accuracy of reinnervation in rats. Female Lewis rats (LEW/SsNHsd) were either trained for 12 weeks (run) or not trained (kept under control conditions, idle). The right sciatic nerves were then excised and reconstructed with 5 mm of a congenic allograft. One week later, training started in the run-run and idle-run groups for another 12 weeks. No further training was conducted in the run-idle and idle-idle groups. Reinnervation was measured using the following parameters: counting of retrogradely labeled motoneurons, walking track analysis, and compound muscle action potential (CMAP) recordings.

Results

In intact rats, the common fibular (peroneal) and the soleus nerve received axons from 549 ± 83 motoneurons. In the run-idle group, 94% of these motoneurons had regenerated 13 weeks after the nerve graft. In the idle-run group, 81% of the normal number of motoneurons had regenerated into the denervated musculature and 87% in both run-run and idle-idle groups. Despite reinnervation, functional outcome was poor: walking tracks indicated no functional improvement of motion in any group. However, in the operated hindlimb of run-idle rats, the CMAP of the soleus muscle reached 11.9 mV (normal 16.3 mV), yet only 6.3-8.1 mV in the other groups.

Conclusion

Treadmill training neither altered the accuracy of reinnervation nor the functional recovery, and pre-operative training (run-idle) led to a higher motor unit activation after regeneration.

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

Introduction: Delayed facial palsy (DFP) is a common complication appearing ≥3 days after neurosurgery. In cases where glucocorticoids are contraindicated, other treatments are needed. Methods: The efficacy of BoNT-A injections was evaluated in patients with DFP after vestibular schwannoma resection. Patients received: Group I, BoNT-A (40–50 IU); Group II, prednisolone (1 mg/kg per day, 5–7 days); Group III, glucocorticoids with BoNT-A; Group IV, refused treatment. Functional efficacy was assessed. Results: Among 75 patients, pretreatment facial nerve dysfunction was mild, moderate, and moderate-to-severe in 48.0%, 33.3%, and 18.7%, respectively. One month post-treatment initiation, Group III had a significantly higher rate of facial symmetry normalization versus Groups II and IV (P < 0.05). After 3 months, complete recovery of facial nerve function was significantly higher in Groups I–III versus Group IV (P < 0.05). Conclusion: BoNT-A injections may be recommended for DFP treatment to attenuate facial asymmetry and improve functional recovery.

[The efficacy of botulinum therapy in treatment of delayed facial palsy after resection of vestibular schwannoma]

Delayed facial palsy is a complication developing 3 or more days after surgery. The etiology and pathogenesis of this condition has not been fully explored, and there are no treatment standards for it. As in the case of Bell's paralysis, glucocorticosteroids (GCSs) are currently used to treat delayed facial palsy. However, patients with contraindications to GCSs need new therapy modalities.

AIM

We aimed to evaluate the efficacy and safety of botulinum therapy in patients with delayed facial palsy after neurosurgical interventions.

MATERIAL AND METHODS

We examined 33 patients with delayed facial palsy developed 3 or more days after resection of vestibular schwannoma. The main group included 18 patients with contraindications to GCSs who received injections of botulinum toxin A (BTA) into the facial muscles of the healthy side for muscle relaxation. The comparison group consisted of 15 patients who received a course of prednisolone (1 mg/kg/day) for 5-7 days. The efficacy of treatment was assessed using the House-Brackmann scale and Clinical Global Impression Scale. The follow-up period after therapy was 3 months.

RESULTS

Delayed facial palsy was more common in the following cases: the facial nerve was located near the antero-inferior tumor pole; the tumor was adherent to the facial nerve; the tumor extended in the oral direction; the tumor had with unclear borders and was 11 to 30 mm in size. In most patients of both groups, facial muscle palsy developed more than 11 days after surgery. Treatment both in the main and control groups resulted in a significant improvement: complete regression of the facial asymmetry in patients of the main group and comparison groups 3 months after treatment onset was 83.3 and 93.3% (House-Brackmann scale), respectively.

CONCLUSION

Botulinum therapy may be recommended for patients with delayed facial palsy developed after vestibular schwannoma resection, who have contraindications to GCSs.