OnabotulinumtoxinA as a promising treatment for primary trochlear headache: A retrospective case series

OBJECTIVES

To report the efficacy of onabotulinumtoxinA (BoNTA) injections in relieving pain in patients with primary trochlear headache (PRTH).

METHODS

Examination of medical records for patients diagnosed with PRTH according to the International Classification of Headache Disorders, 3rd edition criteria and treated with BoNTA. Data were collected for variables related to pain relief, duration of effectiveness, and adverse effects.

RESULTS

Six patients were included in the study. All had previously undergone standard care interventions, including infiltrations or oral treatments, yet experienced treatment failure or symptom recurrence. All patients received 20 units of BoNTA, administered in the corrugator and procerus muscles. Subsequent to the BoNTA injections, all six patients reported substantial pain relief, with five achieving complete remission of symptoms. The analgesic effect persisted for a duration of 3 months. No adverse events were reported in any of the cases.

CONCLUSIONS

Our case series presents the first evidence of the potential of BoNTA as a safe and effective treatment option for PRTH. From a clinical standpoint, having a safer alternative is of paramount significance for patients with limited treatment options, such as those with PRTH. Further research is warranted to validate these findings and explore the long-term efficacy of BoNTA in PRTH management.

Retrospective Analysis of Factors Related to the Long-Term Recovery of Third, Fourth, and Sixth Cranial Nerve Palsy with Etiologies and Clinical Course in a Tertiary Hospital

Purpose

Although various studies have explored the causes and clinical aspects of cranial nerve palsies, there remains a significant gap in understanding the prognostic factors that influence outcomes. In this study, we sought to address this gap by investigating the incidence, etiologies, clinical courses, and factors associated with long-term recovery, with the aim of enhancing the knowledge base in this field and providing valuable insights for improved patient care.

Patients and Methods

This retrospective study evaluated the data gathered from subjects who had third, fourth, and sixth cranial nerve palsy at the ophthalmology outpatient clinic of Phramongkutklao Hospital between April 1, 2012, and April 30, 2022.

Results

Among the three nerves, abducens nerve palsy was the most prevalent finding by most commonly involved. Our study revealed that ischemic and compressive lesions were the most common etiology of oculomotor nerve palsy, comprising 24.6% each. In addition, the most common etiology of trochlear and abducens nerve palsy was trauma, at 31.6% and 27.1%, respectively. Compared with the other nerves, oculomotor nerve palsy was associated with a shorter duration onset of symptoms and recovery period. The best recovery outcomes among the various etiologies were inflammation, ischemic events, and trauma in oculomotor, trochlear, and abducens nerve palsy, respectively. Logistic regression revealed that an onset of <7 days and isolated nerve involvement were significantly associated with good long-term outcomes, with an adjusted odds ratio of 1.73 (95% confidence interval, 1.03-2.89) and 2.56 (95% confidence interval, 1.21-5.39) adjusted for the type of cranial nerve palsy, aged at 50 years, sex, diabetes mellitus, hypertension, dyslipidemia, onset at 7 days, and number of cranial nerves involved, respectively.

Conclusion

The onset of symptoms in less than 1 week and isolated nerve involvement were associated with better prognosis in subjects with third, fourth, and sixth cranial nerve palsy.

Minimally invasive extraocular cranial nerve electromyography

OBJECTIVE

A reluctance to monitor extraocular cranial nerve (EOCN) function has restricted skull base surgery worldwide. Spontaneous and triggered electromyography (EMG) monitoring can be recorded intraoperatively to identify and assess potential cranial nerve injury. Determining the conductive function of EOCNs requires the collection of clear, reliable, and repeatable compound muscle action potentials (CMAPs) secondary to stimulation. EOCN EMG needle electrodes can, although infrequently, cause ocular morbidity including hematoma, edema, and scleral laceration. The aim of this study was to ascertain if minimally invasive 7-mm superficial needle electrodes would record CMAPs as well as standard 13-mm intraorbital electrodes.

METHODS

Conventionally, the authors have monitored EOCN function with intraorbital placement of paired 13-mm needle electrodes into three extraocular muscles: medial rectus, superior oblique, and lateral rectus. A prospective case-control study was performed using shorter (7-mm) needle electrodes. A single minimally invasive electrode was placed superficially near each extraocular muscle and coupled with a common reference. CMAPs were recorded from the minimally invasive electrodes and compared with CMAPs recorded from the paired intraorbital electrodes. The presence or absence of CMAPs was analyzed and compared among EMG recording techniques.

RESULTS

A total of 429 CMAPs were analyzed from 71 EOCNs in 25 patients. The experimental setup yielded 167 true-positive (39%), 106 false-positive (25%), 17 false-negative (4%), and 139 true-negative (32%) responses. These values were used to calculate the sensitivity (91%), specificity (57%), positive predictive value (61%), and negative predictive value (89%). EOCN electrodes were placed in 82 total eyes in 58 patients (CMAPs were obtained in 25 patients). Twenty-six eyes showed some degree of edema, bruising, or bleeding, which was transient and self-resolving. Three eyes in different patients had complications from needle placement or extraction including conjunctival hemorrhage, periorbital ecchymosis, and corneal abrasion, ptosis, and upper eyelid edema.

CONCLUSIONS

Because of artifact contamination, 106 false-positive responses (25%), and 17 false-negative responses (4%), the minimally invasive EMG technique cannot reliably record CMAP responses intraoperatively as well as the intraorbital technique. Less-invasive techniques can lead to an inaccurate EOCN assessment and potential postoperative morbidity. EOCN palsies can be debilitating and lifelong; therefore, the benefits of preserving EOCN function outweigh the potential risks of morbidity from electrode placement. EMG monitoring with intraorbital electrodes remains the most reliable method of intraoperative EOCN assessment.

Outcomes after stereotactic radiosurgery for schwannomas of the oculomotor, trochlear, and abducens nerves

OBJECTIVE

Cranial nerve (CN) schwannomas are intracranial tumors that are commonly managed by stereotactic radiosurgery (SRS). There is a large body of literature supporting the use of SRS for vestibular schwannomas. Schwannomas of the oculomotor nerves (CNs III, IV, and VI) are rare skull base tumors, occurring close to the brainstem and often involving the cavernous sinus. Resection can cause significant morbidity, including loss of nerve function. As for other schwannomas, SRS can be used to manage these tumors, but only a handful of cases have been published so far, often among reports of other uncommon schwannoma locations.

METHODS

The goal of this study was to collect retrospective multicenter data on tumor control, clinical evolution, and morbidity after SRS. This study was performed through the International Radiosurgery Research Foundation. Patients managed with single-session SRS for an oculomotor cranial nerve schwannoma (CN III, IV, or VI) were included. The diagnosis was based on diplopia or ptosis as the main presenting symptom and anatomical location on the trajectory of the presumed cranial nerve of origin, or prior resection confirming diagnosis. Demographic, SRS dose planning, clinical, and imaging data were collected from chart review of the treated patients. Chi-square and Kaplan-Meier analyses were performed.

RESULTS

Seven institutions submitted data for a total of 25 patients. The median follow-up time was 41 months. The median age at the time of treatment was 52 years. There were 11 CN III schwannomas, 11 CN IV schwannomas, and 3 CN VI schwannomas. The median target volume was 0.74 cm3, and the median marginal dose delivered was 12.5 Gy. After SRS, only 2 patients (including the only patient with neurofibromatosis type 2) had continued tumor growth. Crude local control was 92% (23/25), and the 10-year actuarial control was 86%. Diplopia improved in the majority of patients (11/21), and only 3 had worsening following SRS, 2 of whom also had worsened ptosis, both in the context of tumor progression.

CONCLUSIONS

SRS for schwannomas of the oculomotor, trochlear, and abducens nerves is effective and provides tumor control rates similar to those for other cranial nerve schwannomas. SRS allows improvement of diplopia in the majority of patients. SRS should therefore be considered as a first-line treatment option for oculomotor nerve schwannomas.

Diagnosis and Management of Trochleodynia, Trochleitis, and Trochlear Headache

Migraine and tension-type headaches (TTHs) comprise a significant burden of neurological disease globally. Trochleodynia, also known as primary trochlear headache or trochleitis, may go unrecognized and contribute to worsening of these headache disorders. It may also present in isolation. We review the English literature on this under-recognized condition and describe what is known about the theorized pathophysiology, clinical presentation, and differential diagnosis. We also present a management algorithm for patients presenting with trochleodynia.

Microvascular Non-Arteritic Ocular Motor Nerve Palsies-What We Know and How Should We Treat?

Patients with isolated unilateral pupil-sparing third or isolated fourth or sixth nerve palsies over 50 years are often diagnosed with "microvascular extraocular palsies". This condition and its management provoke divergent opinions. We review the literature and describe the incidence, pathology, clinical presentation, yield of imaging, and management. A retrospective diagnosis of exclusion has little practical use. We suggest a pragmatic approach to diagnosis, investigation, and management from initial presentation.

Ilial crest bone graft transposition as treatment for fracture of the medial femoral trochlear ridge in a dog

This is a report of a fracture of the medial trochlear ridge of the distal femur occurring as a major complication after surgery for medial patellar luxation. To address the complication, a non-vascularized iliac bone graft was collected and fixated with two positional screws to the trochlea. An external skeletal fixator was placed to prevent motion of the stifle joint during the healing period and to reduce the risk for fragment dislodgment. One year after the graft was placed the dog's function was satisfactory. This case report indicates that a non-vascularized iliac bone graft provides an alternative for management of fractures of the medial ridge of the distal femur.