Selective Nasal Anterior Superior Oblique Tenectomy for the Treatment of Superior Oblique Myokymia

We describe successful surgical treatment of superior oblique myokymia, which had recurred after superior oblique tenectomy. Single case report. The distal stump of the superior oblique tendon was extirpated by stripping it from the globe. The ipsilateral superior rectus muscle also was recessed, to correct a hypertropia that had resulted from the original superior oblique tenectomy. Complete removal of the distal superior oblique muscle tendon provided definitive relief of superior oblique myokymia. Superior rectus muscle recession, combined with previous inferior oblique myectomy, compensated effectively for loss of superior oblique function.

To investigate the clinical features of congenital ocular elevator muscle palsy and to evaluate the efficacy of surgical treatment. Pre- and post-operative eye position, superior rectus muscle and inferior oblique muscle function, clinical features were examined and analyzed in 11 patients with congenital double elevator palsy of ocular muscles. When fixated with the nonparetic eye, ten of 11 patients showed hypotropia and pseudoblepharoptosis in the primary position; One of 11 patients fixated with the paretic eye and showed hypotropia in the primary position. All cases were a monocular elevation deficiency in abduction and adduction, and showed pseudoblepharoptosis. In ten patients fixated with the nonparetic eye, two of 10 were undergone inferior rectus recession on paretic eyes; six of 10 were undergone inferior rectus recession and superior oblique tenectomy on paretic eyes; two of 10 were applied inferior rectus recession and superior oblique tenectomy on paretic eyes, superior rectus recession was performed on healthy eyes in six months postoperation. The patient fixated with the paretic -eye were undergone superior rectus recession and inferior oblique tenectomy on healthy eyes. Seven patients with exotropia had lateral rectus muscle surgery performed at the time of their vertical operation. Strabismus were complete corrected in 81.8% (9/11) of patients in our study and 18.2% (2/11) of patients were partial corrected. The functions of superior rectus muscle and inferior oblique muscle were not corrected. Nine patients showed complete correction of the psuedoptosis, one patient showed partial correction of the psuedoptosis, one patient did not showed any improvement of the pseudoptosis. We conclude that superior rectus muscle and inferior oblique muscle insufficiency are the primary factors in the etiology of congenital double ocular elevator palsy. Vertical rectus recession and superior oblique tenectomy on paretic eyes is an effective way of surgical treatment the disease.

Superior oblique myokymia (SOM) is a rare, acquired aberration of the innervation of the superior oblique, resulting in episodic monocular contraction of the superior oblique muscle characterized by intermittent rotatory eye movement causing diplopia and oscillopsia. Several treatment modalities have been described to treat SOM, including medication and surgical interventions. There is a paucity of reports describing microvascular decompression (MVD) of the trochlear nerve near the root entry zone for the treatment of a neurovascular conflict. The authors describe a case report of a patient who presented with SOM by a supracerebellar infratentorial approach using microscopic and endoscopic visualization. A 40-year-old woman presented with an 8-month history of rhythmic contractions of her right orbit with worsening double vision and occasional balance issues. Neuro-ophthalmological evaluation which revealed a right-sided SOM. MRI evaluation demonstrated a potential vascular compression by the superior cerebellar artery near the origin of the trochlear nerve. She underwent MVD by a supracerebellar infratentorial approach using microscopic and endoscopic visualization. The patient experienced resolution of her SOM in the immediate postoperative period and a Trochlear nerve palsy that resolved within 6 months. The endoscopic supracerebellar infratentorial approach for MVD of the trochlear nerve is a safe and efficacious approach that provides superior visualization of the trochlear nerve at its origin and in the setting of SOM. This approach shows outcomes comparable with those used in previously described cases.

Superior Oblique Myectomy and Trochlear Resection for Superior Oblique Myokymia

Superior Oblique Myokymia: A Case Report of Surgical Treatment, Review of the Literature, and Consideration of Surgical Approach

High resolution, magnetic resonance imaging was used to quantitatively study the morphometry of the superior oblique muscles of two patients with superior oblique myokymia, as well as 18 superior oblique muscles of 14 patients with normal superior oblique function. The cross sectional area of each superior oblique muscle was measured at 3-millimeter intervals along the entire muscle length. In both cases of myokymia, the affected superior oblique muscles were significantly smaller than normal (P < .05). These anatomical changes in the superior oblique muscle of patients with myokymia suggest that an antecedent injury to the trochlear nerve has occurred. This injury, even if clinically unapparent, may be the initial event which leads to subsequent development of superior oblique myokymia.

We describe the outcomes and long-term follow-up of treatment with anterior orbitotomy with superior oblique myectomy and trochlear resection for superior oblique myokymia. Single-center case report and long-term follow-up of 3 previously published cases of superior oblique myokymia treated with superior oblique myectomy and trochlear resection. Previously reported patients were contacted for long-term follow-up. A fourth patient's complex clinical course is detailed. The surgical procedure is described and contrasted with alternative approaches. Four patients with refractory oscillopsia were treated. Symptom duration before presentation to the authors ranged from 10 to 22 years. All 4 patients had failed medical therapy; 3 of 4 had recurrent myokymia after prior superior oblique tenectomy; 1 of 4 had persistent symptoms despite 3 transcranial microvascular decompressions. After superior oblique myectomy and trochlear resection, all 4 patients reported sustained, complete resolution of oscillopsia in postoperative follow-up of 22, 17, 16, and 2 years. Three of 4 patients did not require additional strabismus surgery. Three of 4 patients reported mild postsurgical supra- and infratrochlear hypesthesia but deemed the symptoms not bothersome. Superior oblique myectomy and trochlear resection is a surgical option for patients with superior oblique myokymia unresponsive to, or intolerant of, medical therapy. It can be used if superior oblique tenectomy fails, or it can be considered as primary surgical management. Further strabismus surgery may be required after this procedure. If used primarily, compensatory inferior oblique weakening should be planned, as it is following primary superior oblique tenectomy. In our view, the orbital approach is preferable to transcranial microvascular decompression.

Novel surgical approach to superior oblique myokymia

Objective: To investigate the clinical presentations and long-term course of patients with superior oblique myokymia (SOM). Methods: The medical records of all 16 patients with the diagnosis of SOM seen in the Neuro-Ophthalmology Unit of The Wilmer Ophthalmological Institute, The Johns Hopkins Hospital, Baltimore, Md, between 1976 and 1993 were reviewed. Follow-up information was obtained for 14 (88%) of the 16 patients. Results: Of the 16 patients with SOM, nine (56%) were male and seven (44%) were female. The age of onset of symptoms ranged from 22 to 50 years (mean age, 34 years). All patients were otherwise healthy with no history of neurologic illness. Seven (44%) of the 16 patients complained of paroxysms of uniocular shimmering, fluttering, or oscillopsia lasting seconds, three (19%) complained of vertical and torsional diplopia, and six (38%) had both types of symptoms. Five (31%) of the 16 patients underwent neuroimaging studies within 1 year of onset of symptoms. All imaging study results were normal. Follow-up information was obtained for 14 patients (88%). The time from onset of symptoms to our most recent contact was 3 to 29 years. Of the seven patients who received no treatment, five (71%) continue to have symptoms to date. Three patients received medical treatment only; one of the three has experienced lasting benefit with carbamazepine. Four patients underwent superior oblique tenectomy combined with inferior oblique myectomy after not responding to medical treatment. All four patients experienced resolution of all ocular symptoms after surgery. Conclusions: Because SOM is a much more chronic disease than formerly realized and because of the poor longterm effects and potential side effects of the medications used, medical treatment of SOM is not the optimum way to manage the disease. Extraocular muscle surgery is the treatment of choice when symptoms of SOM are intolerable to the patient.

A woman with superior oblique myokymia (SOM) was cured of her condition by performing a Harada-Ito procedure. This procedure involves transposing the anterior portion of the superior oblique tendon, which is responsible for cyclorotation, nasally to create an effective weakening of the anterior portion of the tendon instead of temporal displacement utilized for superior oblique paresis. We measured the patient's eye movements before and after surgery, using the magnetic search coil technique, and confirmed that (1) the SOM was abolished and (2) vertical eye movements, including saccades, were unaffected.

Purpose To do an epidemiological study of the proposal that superior oblique myokymia (SOM) is a migraine motor aura and propose a pathophysiological basis for the etiology of SOM. Migraine aura is a paroxysmal spreading depression of both excitatory and inhibitory neurons in the brain. These may be sensory neurons (numbness), motor neurons (dysarthria) and inhibitory neurons (chorea). Superior oblique myokymia is bursts of very rapid, jerky contrations of a superior oblique muscle causing shaking of one eye. Interfunctioning of the cortex and basal nuclei maintains stability of eye movements. Spreading depression of the cortex would cause inhibition of the inhibitory GABAergic fibres from basal ganglia to the midbrain which could result in paroxysmal firing of the 4th nerve neurons in SOM. A finely‐tuned homeostatic balance of GABAergic interneuron tone controls excitatory activation of CNS motorneurons. Small changes in GABAergic inhibition have profound effects on excitability. SOM, like auras, usually spontaneously disappears for years or permanently, which may account for the "success" of surgical treatments. The most effective treatment of SOM is gabapentin, a congener of GABA which enhances its activity. Methods Thirty seven patients with superior oblique myokymia had detailed questioning about a history of migraine headaches and auras. Results Every one of 37 patients with superior oblique myokymia had a history of migraine symptoms fulfilling all International Headache Society criteria. Every one had a history of migraine visual auras and many had also had sensory and dysphasic auras. Conclusion Epidemiological correlation and a pathophysiological explanation support the proposal that superior oblique myokymia is a migraine motor aura.

Superior oblique myokymia is an intermittent uniocular microtremor caused by uncontrolled contractions of the superior oblique muscle, termed by Hoyt and Keane. As all the previously reported cases were healthy individuals, its lesion and mechanism have not been clarified. In this report, I introduced a patient with a cerebellar tumor who presented with superior oblique myokymia.A 41-year-old woman was admitted to the Nihon University Hospital with complaints of headache, dizziness and diplopia. A right cerebellar cyst was observed on computerized tomography and partial resection of this tumor was performed. Two months after this operation, she complained of oscillopsia and torsional diplopia. At that time, rapid, smallamplitude, intorted movements, that is superior oblique myokymia, were noted only in the right eye. This abnormal eye movement disappeared in one week. Thereafter, left cerebellar signs became apparent and visual suppression of nystagmus was reduced on both sides. Therefore, it was suspected that the tumor had already extended to the left cerebellum.From this clinical course and the experimental data of Ito, it was suggested that when the left flocculus was stimulated, the left superior vestibular nucleus was inhibited. Disinhibition of the right superior oblique muscle and disfacilitation of the right inferior oblique muscle resulted and the intorted movement appeared in the right eye.From these results, it seemed that the lesion responsible for superior oblique myokymia was the contralateral flocculus and this characteristic eye movement was produced when this region was stimulated temporarily.

Superior oblique myokymia is a rare condition, characterized by spontaneous rhythmic contractions of the superior oblique muscle and was first described by Duane in 1906. However, the pathophysiology of this condition remains poorly understood even today. A number of medical and surgical treatment modalities have been tried, with variable results. We report a case of superior oblique myokymia in a pregnant female, which could be triggered with flashlight stimulation, and the result of treatment with timolol maleate 0.5% ophthalmic solution.

Surgical Management of Myokymia of the Superior Oblique Muscle

In patients operated on for superior oblique myokymia with superior oblique tenotomy or tenectomy, symptoms of oscillopsia recur in approximately one-half. Failure of treatment may be caused by incomplete transection of the tendon or by residual attachments and postoperative adhesions between the proximal segment of superior oblique tendon and the globe which allow superior oblique muscle contractions to be partially transmitted to the globe. We report a patient with recurrent symptoms of superior oblique myokymia following superior oblique tenectomy who was successfully managed with superior oblique myectomy and trochlectomy via an anterior orbital approach.