Residual Apical Lamina Papyracea as a Cause for Persistent Dysthyroid Optic Neuropathy After Orbital Decompression

Orbital Decompression: Conceptual Approach for Orbital Volume Expansion

PURPOSE

To review the advances in the surgical techniques of orbital decompression.

METHODS

A literature review of orbital decompression surgery and experience-based consideration of bony areas for decompression.

RESULTS

In the 100-year-plus span of orbital decompression literature, multiple incisions and multiple bone and fat removal strategies have been described. In general, bone removal has been conceptualized as consisting of 4 walls of the orbit. However, the orbital bony anatomy is more subtle than a simple box, and considering 6 areas of potential bony removal allows a more nuanced paradigm for clinical decision-making and for understanding various technique descriptions. Historical and current techniques, and surgical planning and decision-making, are described from the perspective of a 6 area paradigm. Potential complications are reviewed.

CONCLUSION

A conceptual framework for orbital decompression focusing on 6 potential areas of bone removal provides a nuanced and flexible paradigm for understanding and describing surgical techniques, and for designing individualized surgery. Orbital decompression surgery should be customized to the patient's anatomy and symptoms.

Dysthyroid Optic Neuropathy

PURPOSE

Dysthyroid optic neuropathy (DON) is a sight-threatening complication of thyroid eye disease (TED). This review provides an overview of the epidemiology, pathogenesis, diagnosis, and current therapeutic options for DON.

METHODS

A literature review.

RESULTS

DON occurs in about 5% to 8% of TED patients. Compression of the optic nerve at the apex is the most widely accepted pathogenic mechanism. Excessive stretching of the nerve might play a role in a minority of cases. Increasing age, male gender, smoking, and diabetes mellitus have been identified as risk factors. Diagnosis of DON is based on a combination of ≥2 clinical findings, including decreased visual acuity, decreased color vision, relative afferent pupillary defect, visual field defects, or optic disc edema. Orbital imaging supports the diagnosis by confirming apical crowding or optic nerve stretching. DON should be promptly treated with high-dose intravenous glucocorticoids. Decompression surgery should be performed, but the response is incomplete. Radiotherapy might play a role in the prevention of DON development and may delay or avoid the need for surgery. The advent of new biologic-targeted agents provides an exciting new array of therapeutic options, though more research is needed to clarify the role of these medications in the management of DON.

CONCLUSIONS

Even with appropriate management, DON can result in irreversible loss of visual function. Prompt diagnosis and management are pivotal and require a multidisciplinary approach. Methylprednisolone infusions still represent first-line therapy, and surgical decompression is performed in cases of treatment failure. Biologics may play a role in the future.