Onset and Resolution of Ocular Motor Cranial Nerve Palsies Following the Use of Intra-Arterial Chemotherapy for Retinoblastoma.

Abstract

Introduction: Intra-arterial chemotherapy (IAC) has revolutionised the treatment of retinoblastoma with respect to eye salvage. We present a case series assessing the onset and resolution of cranial nerve palsies following IAC in the treatment of retinoblastoma.

Materials and methods: A retrospective case series examining children treated with IAC between 2014 and 2020 for refractory retinoblastoma. The initial approach to catheterisation was the same in all cases. All patients were assessed by an orthoptist and those with nerve palsies were followed up for resolution.

Results: There were 41 patients treated with IAC in this time period with a median age of 15 months (5-125). Of these, 7 (17%) developed cranial nerve palsies (NP). These were either 3^rd (3 of 7), 6^th (1 of 7) or mixed 3^rd and 6^th (3 of 7) palsies. Onset was at a median of 5 days after the injection. Five resolved and resolution was at a median of 3 months (0.75-26) from onset. Two children still had extra-ocular muscle involvement due to NPs that did not resolve and the cumulative doses of Melphalan were 47.5 mg and 37.5 mg.  All children who had cranial nerve palsies that resolved had a cumulative dose of less than 20 mg of Melphalan.

Conclusion: Cranial nerve palsy is an infrequent occurrence after IAC but families need to be aware of this as a complication. It is reassuring that the majority resolve. In our experience, a high cumulative dose of melphalan due to the refractory nature of the tumour increases the risk of this complication long term.