Facial nerve paralysis, synkinesis following defective healing of the facial nerve, hemifacial spasm, blepharospasm, aesthetic applications, prevention of scar formation

Classical indications to be treated with BTA are the treatment of patients suffering from a blepharospasm or a hemifacial spasm. Patients with a blepharospasm suffer from repetetive cramps of the orbicularis oculi muscles leading to eye closure. Patients suffering from a hemifacial spasm experience repetetive tonic-clonic cramps of one half of the mimic musculature (example see Fig 1). BTA is suited to treat these diseases by injecting the substance into certain muscle depending on the clinical picture. Doses vary from 1.25 to 5 units Botox^® per injection point.

BTA is also helpful in other disorders of the mimic musculature. In some cases a facial nerve paralysis leads to an affection of the cornea with severe problems like a "keratitis e lagophthalmo". In such cases an injection into the levator palpebrae muscle can close the eye for some time to protect the cornea 5. We use dosages of 5–10 units Botox^®, the injection is done subcutaneously in the middle of the upper lid. After about 3–4 months the eye "opens" again and that is usually referring to the regeneration time of the paralysis.

In addition the esthetic outcome of a paralysis of the marginal branch of the facial nerve can be improved by injecting 2.5–5 units Botox^® into the depressor labii muscle of the normal side 6.

Synkinesis are a non-avoidable sequelae following reconstruction of the facial nerve in patients suffering from malignant tumors of the parotid gland. Synkinesis are characterized by synchronous but not intended movements of certain areas of mimic muscles becoming mostly evident during spontaneous movements of the face based on emotional expressions. Mass movements can be reduced using BTA. This options has been described first by our group 789.

We normally inject BTA using 6 injection-points around the eye to reduce foreign movements of the orbicularis oculi muscle (see Fig 2). The complete injection design and the total dosage depend on the extent of mass movements and may vary from patient to patient. We normally use dosages from 1.25–5 units Botox^® on each injection point. Side effects are very rare ; the reason for that could be that lower dosages are necessary to treat synkinesis compared to other facial dyskinesis like hemifacial spasm or blepharospam.

Synkinesis of the platysma are of special interest. We focused on this problem and found an acceptable decrease of complaints in treated patients 1011.

Another interesting indication is the intraoperative application of BTA during the surgical supply of fresh wounds of the face. It has been demonstrated that weakening of face muscles neighbouring facial wounds leads to a better aesthetic outcome. The reason may be that after the immobilization of the treated muscles the borders of fresh wounds better adapt without muscular tension leading to excellent aesthetic results 12.

The application of BTA to improve the aesthetic state of the face is another wide field 13. Periocular and many other types of wrinkles are in the focus here (example see Fig 3).

For all facial applications the duration of the effect normally begins within 3–5 days and amounts 3–4 months. Then the treatment has to be repeated. Side effects like a ptosis (Fig 4), a "keratitis e lagophthalmo" or tearing are rare.

An important, increasing field of application is the use of BTA in different pain syndromes, especially in patients suffering from tension headache, migraine and chronic daily headache (for review see 1415).

Repetitive dystonic contractions of the muscles of the soft palate (palatoglossus and palatopharyngeus muscles, salpingopharyngeus, tensor and levator veli palatini muscles) lead to a rhythmic elevation of the soft palate 16. This can cause speech and also swallowing disorders due to a velopharyngeal insufficiency. Most patients suffering from palatal tremor complain of "ear clicking". This rhythmic tinnitus is caused by a repetitive opening and closure of the orifice of the Eustachian tube. A particular sequelae of pathological movements of soft palate muscles is the syndrome of a "patulous Eustachian tube" 17. These patients suffer from "autophonia" caused by an open Eustachian tube due to the increased muscle tension of the paratubal muscles (salpingopharyngeus, tensor and levator veli palatini muscles).

In a first treatment session, the application of five units of Botox^® (uni- or bilaterally) into the soft palate is adequate in most cases. If necessary, this can be increased to two times 15 units of Botox^®. The application is normally performed transorally (transpalatinal or via postrhinoscopy) under endoscopic control. To optimise the detection of the target muscle, injection under electromyographic control is recommended. To avoid side effects such as iatrogenic velopharyngeal insufficiency the treatment should be started with low doses as described above.

Hypersalivation is of high relevance for patients suffering from different diseases (see Fig 6) 2122. Some patients of this group are not able to swallow their saliva because of a stenosis of the upper esophagus sphincter region caused by scar formation after a tumor resection. In other patients the sensory control of the entrance of the larynx is reduced and therefore saliva may pass the larynx and reach the trachea and the bronchus. That leads to permanent aspiration and aspiration pneumonia. In a third group of patients problems of the wound healing process after extended surgery exist, like fistulas following laryngectomies. In these cases saliva is a very aggressive agens preventing a normal healing process. In addition, different neurological disorders include hypersalivation as a very serious symptom.

Based on our expanded experiences literature, we prefer in our patients the ultra-sound-guided injection into the parotid and submandibular gland on each side. We inject into the parotid gland 22.5 units Botox^® on each side, distributed on 3 points. The submandibular glands are treated by a ultrasound-guided one or 2-point injection of a total of 15 units Botox^® per gland. It has been shown by objective datas in a lot of papers that BTA injections are effective in reducing the saliva flow, accompanied by very few side effects.

Gustatory sweating is a common sequelae following parotid gland surgery 232425262728. The treatment of gustatory sweating with BTA has been described first by our group in 1994 (first treated patient December 1993 2327) and became the first line treatment option in these patients.

To get an optimal outcome, we recommend marking of the sweating area by Minor's test and then dividing the sweating area in "boxes" using a waterproof pen. The injections are done intracutaneously (see Fig 7).

The effectiveness of BTA treatment in patients with gustatory sweating has been confirmed by a lot of other authors. Some patients report a benefit after BTA-injection already at the same day and interestingly, the positive effect remains much longer than in patients with movement disorders 24. Some patients reach several years of a symptom free interval.

The treatment of hyperhidrosis of the head and/or the face are based on the same principles as described for patients with gustatory sweating. The doses which are reached for each individual patient depend on the size of the sweating area to be treated.

Hyperlacrimation (example see Fig 8) can be caused by a stenosis of the lacrimal duct, by misdirected secretory fibers following a degenerative paresis of the facial nerve (crocodile tears) or after a mechanical irritation of the cornea (in patients with a lagophthalmus). The application of BTA is a helpful tool to reduce pathological tearing in these patients in order to reach normal levels of tear liquid production 293031. We inject 5–10 units Botox^® into the pars palpebralis of the lacrimal gland (technique see Fig 9). None of our patients suffered from a "dry eye" after BTA treatment of the lacrimal gland.

In the last few years, the application of Botulinum toxin type A in patients with intrinsic or allergic rhinitis has been described 323334. In experimants the existence of apoptosis of nasal glands has been demonstrated 33. The main symptom in patients suffering from these diseases is extensive rhinorrhea with secretions dripping from the nose.

There are two methods for applying BTA in these patients (Fig 10): it can either be injected into the middle and lower nasal turbinates 32, or it can be applied with a sponge soaked in a solution of BTA (Fig. 10) 34.

For the injection we use 10 units of Botox^® for each turbinate (middle and lower nasal turbinates).

With the other technique, the sponges are loaded with a solution containing 40 units of Botox^® and one is applied on each side.

The positive effect of the injections has been demonstrated in placebo-controlled studies 32. Nasal secretion is reduced for about 12 weeks (example see Fig 11). Side effects such as epistaxis or nasal crusting were uncommon.

Some new developments in the use of BTA in head and face medicine are to mention here (see 35). BTA application in patients suffering from tinnitus 36 or depressions 37 have been treated with BTA. Further investigations will show whether there is a real hope for clinical use of BTA in these indications.