Subtenon injection of botulinum toxin for treatment of traumatic sixth nerve palsy

Botulinum Toxin Injection for the Treatment of Third, Fourth, and Sixth Nerve Palsy: A Meta-Analysis

The efficacy of botulinum toxin injection for the treatment of third, fourth, and sixth nerve palsy was evaluated. PubMed, Scopus, EMBASE, Web of Science, and Google Scholar databases were searched. Data about the duration of palsy (acute vs chronic), cause of the palsy, type of toxin used, mean dose, and other background characteristics were collected. Outcome variables were success rate (defined by alleviation of diplopia or reduction in eye deviation) and standardized mean difference of prism diopter and abduction deficit before and after injection. The Joanna Briggs Institute checklist was implemented for the risk of bias assessment. The analysis included 38 articles, comprising 643 patients. The overall treatment success rate in acute and chronic nerve palsy was 79% and 33%, respectively. The success rate was not significantly different between different subgroups of age, type of botulinum toxin, pre-injection prism diopter, etiology of the palsy, duration of follow-up, and mean dose of botulinum toxin injection. However, in both acute and chronic palsy, diabetes etiology was accompanied by the highest success rate. Overall symptomatic response to botulinum injection was 84% (95% CI: 67% to 96%), whereas functional response was observed in 64% (95% CI: 47% to 79%) of the patients. The odds ratio for the success rate of treatment of palsies with botulinum toxin versus expectant management was 2.67 (95% CI: 1.12 to 6.36) for acute palsy and 0.87 (95% CI: 0.17 to 4.42) for chronic palsy. Botulinum toxin can be used for the treatment of acute third, fourth, and sixth nerve palsy, especially in patients with acute palsy and more severe tropia. [J Pediatr Ophthalmol Strabismus. 2024;61(3):160-171.].

Botulinum toxin injection without electromyographic guidance in consecutive esotropia

Purpose

To investigate the efficacy of botulinum toxin injection without electromyographic guidance for the treatment of consecutive esotropia.

Methods

A retrospective study was performed on 49 subjects with consecutive esotropia who received botulinum toxin injection in the medial rectus muscles without the use of electromyographic guidance. Treatment was considered successful if the final ocular alignment was orthotropic or esodeviation was ≤10 prism diopters (PD) during distant fixation.

Results

The mean age was 15.2 ± 8.3 years. The mean esodeviation before injection was 21.8 ± 9.1 PD at distance and 21.3 ± 8.3 PD at near. The mean number of injections per patient was 1.3 ± 0.7, and 46 patients (93.9%) received two or fewer injections. At 6 months after the final injection, the mean angle of esodeviation was 7.3 ± 6.0 PD at distance and 7.5 ± 6.6 PD at near (all p<0.001), and 69.4% showed successful alignment. By multivariate analysis, an initial postoperative esodeviation of ≤18 PD at one month after exotropia surgery was considered to be a predictive factor for successful botulinum toxin injection (P = 0.007). Vertical deviation and/or ptosis occurred in 4 patients (8.2%) at two weeks after injection, which all resolved within three months. There was no recurrence of exotropia up to the final follow-up examination.

Conclusion

Botulinum toxin injection without electromyographic guidance is safe and effective in the treatment of consecutive esotropia without causing recurrent exotropia. Successful botulinum toxin injection is likely in patients with an initial postoperative esodeviation of 18PD or less at one month after exotropia surgery.

Use of Botulinum Toxin in Ophthalmology

Botulinum toxin is an important treatment for many conditions in ophthalmology, including strabismus, nystagmus, blepharospasm, hemifacial spasm, spastic and congenital entropion, corneal exposure, and persistent epithelial defects. The mechanism of action of botulinum toxin for both strabismus and nystagmus is the neuromuscular blockade and transient paralysis of extraocular muscles, but when botulinum toxin is used for some forms of strabismus, a single injection can convey indefinite benefits. There are two unique mechanisms of action that account for the long-term effect on ocular alignment: (1) the disruption of a balanced system of agonist-antagonist extraocular muscles and (2) the reestablishment of central control of alignment by the binocular visual system. For other ocular conditions, botulinum toxin acts through transient paralysis of periocular muscles. Botulinum toxin is a powerful tool in ophthalmology, achieving its therapeutic effects by direct neuromuscular blockade of extraocular and periocular muscles and by unique mechanisms related to the underlying structure and function of the visual system.

Bilateral Abducent Nerve Palsy After Neck Trauma: A Case Report

INTRODUCTION

The abducent nucleus is located in the upper part of the rhomboid fossa beneath the fourth ventricle in the caudal portion of the pons. The abducent nerve courses from its nucleus, to innervate the lateral rectus muscle. This nerve has the longest subarachnoid course of all the cranial nerves, it is the cranial nerve most vulnerable to trauma. It has been reported that 1% to 2.7% of all head injuries are followed by unilateral abducent palsy, but bilateral abducent nerve palsy is extremely rare.

CASE PRESENTATION

A 65-year-old woman presented to the emergency department following a motor vehicle accident. A neurological assessment showed the patient's Glascow coma scale (GCS) to be 15. She complained of double vision, and we found lateral gaze palsy in both eyes. A hangman fracture type IIA (C2 fracture with posterior ligamentous C1 - C2 distraction) was found on the cervical CT scan. A three-month follow-up of the patient showed complete recovery of the abducent nerve.

CONCLUSIONS

Conservative treatment is usually recommended for traumatic bilateral abducent nerve palsy. Our patient recovered from this condition after three months without any remaining neurological deficit, a very rare outcome in a rare case.

A case of traumatic bilateral abducens and unilateral hypoglossal nerve palsy

Patient: Female, 47

Final Diagnosis: Traumatic bilateral abducens • unilateral hypoglossal nerve palsy

Symptoms: Diplopia

Medication: —

Clinical Procedure: —

Specialty: Neurology

Objective: Rare disease

Uses of Botulinum Toxin a in Ophthalmology

Introduction:

Botox® (serotype A) is currently available and used to treat various ophthalmological conditions. The aim of our study was to review the current indications, side-effects and updates on the clinical use of botulinum toxin- A (Btx-A) in the field of ophthalmology.

Methods:

A literature search using the keywords “Botulinum Toxin”, “Botulinum Toxin A”, “Botox” and “Ophthalmology” was performed using Pubmed. Articles describing the use of botulinum toxin A were selected and reviewed.

Results:

The uses of Btx-A in ophthalmology can be broadly classified into four categories: eyelid, strabismus, cosmetic and others. In the eyelid, it can be used to treat blepharospasm, hemifacial spasm, apraxia of lid opening or induce ptosis in lid retraction and exposure keratopathy. In strabismus management, it can be injected into overacting muscles to realign the eyes. For cosmesis, it can be used to relax facial muscles to reduce wrinkles while other indications include treatment of chronic dry eye, lacrimal hypersecretion and pain relief in acute angle closure attack. Complications of the injection include local effects like ecchymosis, pain or infection and spillover effects like ptosis, diplopia, lagophthalmos, mid facial weakness and dry eyes.

Conclusion:

The clinical application of botulinum toxin A in ophthalmology is extensive. When considering its application in clinical practice, one should be mindful of the indications, risks and benefits of the procedure. When properly delivered, its potential as an efficacious, minimally-invasive treatment modality can be maximised in patient management.

Effects of botulinum A toxin injection on the extraocular muscle fiber layers: comparison between subtenon injection and intramuscular injection

PURPOSE

To compare the morphological changes following injection of botulinum A toxin to the extraocular muscle fiber layers with those following injection to the subtenon intramuscular system.

METHODS

Twelve New Zealand white rabbits were divided into two groups. In the first group (six rabbits), four received injections of 10 units of botulinum A toxin into the subtenon space of the superior rectus muscle OD, and the same dose of botulinum A toxin was injected directly into the superior rectus muscle OS. The other two rabbits in the first group were labeled as control animals; 0.1 ml of normal saline was injected into the subtenon space OD, and direct intramuscular injection was performed on the opposite eye. The animals in the first group were killed after 4 weeks to measure the average diameter of the muscle fibers in both the orbital and global layer. In animals of the second group (six rabbits), the same procedures were performed and the animals were killed 12 weeks after treatment.

RESULTS

The average diameter of muscle fibers in both the orbital layer and global layer was markedly reduced in all of the botulinum A toxin-injected groups at 4 weeks after treatment compared with the controls. There was no difference in the average diameter of the muscle fibers between the orbital layer of the subtenon-injected group and that of the intramuscular-injected group at 4 weeks after treatment, but the average diameter of the muscle fibers in the global layer was significantly reduced in the intramuscular-injected group compared with the subtenon-injected group at 4 weeks after treatment. At 12 weeks following treatment, there was no difference in the average diameter between the botulinum A toxin-injected group and the control group regardless of where the toxin was injected.

CONCLUSION

Subtenon injection of botulinum A toxin induced similar morphological changes as direct intramuscular injection in the extraocular muscle fiber layers. These results suggest the possibility of clinical applications of subtenon botulinum A toxin injection for the treatment of strabismus.

The role of Botulinum toxin in management of acute traumatic third-nerve palsy

PURPOSE

To study the effect of botulinum toxin A injection in the management of paralytic exotropia resulting from acute traumatic third (oculomotor) nerve palsy.

METHODS

Nine patients with acute traumatic partial third-nerve palsy of less than 2 months' duration were treated by injection of botulinum toxin A into the ipsilateral lateral rectus muscle. The horizontal deviation angles before and after the injections were recorded. A distance exotropia of less than 10(Delta) or absence of diplopia in the primary position at the last follow-up was defined as recovery.

RESULTS

The mean preinjection deviation in the primary position was 48.3(Delta) of exotropia, and the mean postinjection deviation in the primary position was 14.2(Delta) at the last follow-up. Seven patients experienced recovery and regained single binocular vision in the primary position. The overall recovery rate was 77.8%. Two patients did not recover and subsequently underwent strabismus surgery.

CONCLUSIONS

Patients with acute traumatic partial third-nerve palsy treated by injection of botulinum toxin A in the lateral rectus muscle showed marked recovery when injection was performed within 2 months of the onset of palsy. Botulinum toxin injection into the lateral rectus muscle may provide temporary relief of symptoms in some patients and seems to be a useful treatment option in cases of acute traumatic third nerve palsy in the short-term.

Botulinum toxin injection with and without electromyographic assistance for treatment of abducens nerve palsy: a pilot study

PURPOSE

To compare the effects and complications of botulinum toxin injection into the medial rectus muscle with and without electromyographic (EMG) assistance for treatment of abducens nerve palsy.

METHODS

In a prospective, comparative, interventional case series, botulinum toxin was injected into the medial rectus muscle of 23 patients with esotropia secondary to abducens nerve palsy within 3 months of onset. Patients were randomly assigned to two groups. The injection was given with EMG assistance in the first (EMG group) and without EMG in the second group (no-EMG group). Success was defined as a distance esotropia of no more than 10(Delta) in the primary position. Angle of deviation was recorded preoperatively and at 1 week, 3 months, and 6 months; any postoperative complications and side effects were noted.

RESULTS

There were 11 patients in the EMG and 12 patients in the no-EMG group. The ocular deviations were significantly improved in both groups with an overall 6 month success rate of 52.2% (p = 0.008 in the EMG group, p = 0.006 in the no-EMG group). Success rates and mean changes of the angle of deviation were not statistically different between the two groups. Postinjection blepharoptosis was found to be significantly more in the EMG group (p = 0.009).

CONCLUSIONS

The effectiveness of botulinum toxin injection is the same with or without EMG assistance into the medial rectus muscle for treatment of abducens nerve palsy. EMG assistance is associated with more blepharoptosis.

Botulinum toxin in the treatment of strabismus. A review of its use and effects

Botulinum Toxin as a medical therapy was introduced by Dr Alan Scott more than 20 years ago. The first clinical applications of Botulinum Toxin type A (BT-A) were for the treatment of strabismus and for periocular spasms. Botulinum Toxin type A is often effective in small to moderate angle convergent strabismus (esotropia) of any cause, and may be an alternative to surgery in these cases. Botulinum Toxin type A may have a role in acute or chronic fourth and sixth nerve palsy, childhood strabismus and thyroid eye disease. The use of BT-A for strabismus varies enormously in different cities and countries for no apparent reason. Botulinum Toxin type A may be particularly useful in situations where strabismus surgery is undesirable. This may be in elderly patients unfit for general anaesthesia, when the clinical condition is evolving or unstable, or if surgery has not been successful. Botulinum Toxin type A can give temporary symptomatic relief in many instances of bothersome diplopia irrespective of the cause. Ptosis and acquired vertical deviations are the commonest complications encountered. Vision-threatening complications are rare. Repeated use of BT-A is safe.

Delayed lateral rectus palsy following resection of a pineal cyst in sitting position: direct or indirect compressive phenomenon?

A rare case of delayed lateral rectus palsy in a patient following resection of a pineal lesion in the sitting position is presented. Postoperative pneumocephalus is common following craniospinal surgical intervention in the sitting position. The sixth cranial nerve is frequently injured because of its prolonged intracranial course. A 13-year-old girl was evaluated for unremitting headaches. No focal deficits were demonstrated on neurological examination. Magnetic resonance imaging revealed a cystlike pineal region mass with peripheral enhancement following intravenous contrast administration. A supracerebellar infratentorial craniotomy was performed in the sitting position, and complete resection of the lesion was achieved. Her postoperative course was complicated by sixth nerve palsy on the third postoperative day. Her symptoms improved with conservative management. The occurrence of sixth cranial nerve palsy secondary to pneumocephalus is a rare entity. Even rarer is the report of this anomaly following craniotomy in the sitting position. This patient's symptoms manifested in a delayed fashion. Although uncommon, this complication should be considered in patients undergoing cranial or spinal surgical interventions in this position.

Botulinum Toxin in Ophthalmology

Since its introduction into clinical medicine in 1980, botulinum toxin has become a major therapeutic drug with applications valuable to many medical sub-specialties. Its use was spearheaded in ophthalmology where its potential applications have expanded to cover a broad range of visually related disorders. These include dystonic movement disorders, strabismus, nystagmus, headache syndromes such as migraine, lacrimal hypersecretion syndromes, eyelid retraction, spastic entropion, compressive optic neuropathy, and, more recently, periorbital aesthetic uses. Botulinum toxin is a potent neurotoxin that blocks the release of acetylcholine at the neuromuscular junction of cholinergic nerves. When used appropriately it will weaken the force of muscular contraction, or inhibit glandular secretion. Recovery occurs over 3 to 4 months from nerve terminal sprouting and regeneration of inactivated proteins necessary for degranualtion of acetylcholine vesicles. Complications are related to chemodenervation of adjacent muscle groups, injection technique, and immunological mechanisms.

Botulinum toxin injection of the inferior oblique muscle for the treatment of superior oblique muscle palsy

PURPOSE

To evaluate botulinum toxin injection of the inferior oblique muscle for management of superior oblique (SO) paresis.

METHODS

We undertook a prospective case series of injections of the ipsilateral inferior oblique (IO) muscle with 10-20 units of botulinum toxin type A in patients with a SO muscle palsy/paresis of less than 2 years' duration.

RESULTS

We enrolled 16 patients (18 eyes) with a mean age of 33.7 years. The median time from onset of symptoms until injection was 6 months. The cause of paresis was trauma for 81% of the patients. The mean hypertropia decreased from 6.4(Delta) to 1.9(Delta) at 6 months after treatment. Other clinical measures improved: mean IO overaction from + 1.7 to + 0.6, mean SO underaction from -1.5 to -0.4, mean subjective torsion from 9.3 degrees to 0.4 degrees , and mean head tilt from 8.4 degrees to 1.1 degrees.

CONCLUSIONS

Botulinum toxin injection to IO muscle reduces the symptoms of SO paresis while patients are waiting for recovery.

Use of botulinum toxin in strabismus

PURPOSE OF REVIEW

The history, pharmacology, indications, complications, and success rates of botulinum administration are discussed in this review as they relate to strabismus and associated conditions.

RECENT FINDINGS

Botulinum has been used to treat strabismus and a variety of other ocular conditions for over three decades. Alan Scott initially investigated extraocular muscle paralysis by botulinum injection in 1973, and in the ensuing years botulinum has been evaluated as a treatment for horizontal and vertical strabismus, nystagmus, dissociated vertical deviation, sensory strabismus, ophthalmoplegia, and paradoxical diplopia.

SUMMARY

Botulinum administration is a strabismus treatment option that may be considered for some strabismus patients; in select cases botulinum is a reasonable and preferable alternative to surgery. Current clinical recommendations regarding botulinum should be considered in the context of the existing comparative studies that are summarized in this review. Since there are very limited data directly comparing the success rates of botulinum with standard strabismus surgery, additional, well designed prospective studies are needed. Data from such studies would enable recommendations for strabismus management to be formulated using an evidence-based approach.