Botulinum toxin in the treatment of drooling in tetraplegic patients with brain injury

Abstract

Objective: To investigate the effect of botulinum toxin type A (BTA) injection into the salivary gland and to evaluate the changes of drooling in varied postures in tetraplegic patients with brain injury.

Methods: Eight tetraplegic patients with brain injury were enrolled. BTA was injected into each parotid and submandibular gland of both sides under ultrasonographic guidance. Drooling was measured by a questionnaire-based scoring system for drooling severity and frequency, and the sialorrhea was measured by a modified Schirmer test for the patients before the injection, 3 weeks and 3 months after the injection. Drooling was evaluated in each posture, such as supine, sitting, and tilt table standing, and during involuntary mastication, before and after the injection.

Results: The severity and frequency of drooling and the modified Schirmer test improved significantly at 3 weeks and 3 months after the injection (p<0.05). Drooling was more severe and frequent in tilt table standing than in the sitting position and in sitting versus supine position (p<0.05). The severity of drooling was significantly increased in the patients with involuntary mastication (p<0.05).

Conclusion: Salivary gland injection of BTA in patients with tetraplegia resulting from brain injury who had drooling and sialorrhea could improve the symptoms for 3 months without complications. The severity and frequency of drooling were dependent on posture and involuntary mastication. Proper posture and involuntary mastication of the patients should be taken into account in planning drooling treatment.

Keywords: Botulinum toxins; Drooling; Posture; Salivary glands; Ultrasonography.

Fig. 1

Representative ultrasound data. (A) Ultrasound-guided injection into the salivary glands (left parotid gland) and (B) ultrasound image of the injected parotid gland.

Fig. 2

Performance of the modified Schirmer test. For objective measurement of drooling, the Schirmer test strip was placed near the submandibular gland of the patient and salivation was measured as the length of saliva permeation after 5 minutes.

Fig. 3

The severity and frequency scales of drooling before botulinum toxin A injection and at 3 weeks and 3 months after the injection in different postures. Both scales of drooling decreased significantly at 3 weeks and 3 months after the injection (^*p<0.05).

Fig. 4

Modified Schirmer test results in the supine position before botulinum toxin A injection and 3 weeks and 3 months after injection. Excessive salivation improved significantly 3 weeks and 3 months (^*p<0.05) after the injection.

Fig. 5

The severity and frequency scales of drooling with or without involuntary mastication. The severity of drooling increased significantly in the patients with involuntary mastication (^*p<0.05).