Clinical features and management of orbital floor fractures are discussed in Chapter 27 of this volume and in BCSC Section 7, Oculofacial Plastic and Orbital Surgery. The discussion in this chapter focuses on motility abnormalities in patients with these fractures.
Diplopia in the immediate postinjury stage is common and not necessarily an indication for urgent intervention. Indications and timing for surgical repair are discussed in Chapter 27 of this volume and in BCSC Section 7, Oculofacial Plastic and Orbital Surgery. Depending on the site of the bony trauma, muscles can be either restricted due to entrapment or paretic due to muscle contusion or nerve damage. “Flap tears” of the inferior rectus muscle have also been described by some authors as a cause of limitation of elevation, depression, or both. Paresis of a muscle may resolve over several months. If the fracture requires surgery, the range of eye movements may improve. By contrast, fibrosis after trauma may cause restriction to persist even after successful repair of the fracture.
Treatment of strabismus is usually necessary when diplopia persists in primary position or downgaze or there is an associated compensatory head position. Some mild limitations of eye movements can be managed with prisms.
Planning of eye muscle surgery depends on the fields where diplopia is present and on the relative contributions of muscle restriction and paresis. Any flap tear discovered on exploration of the inferior rectus muscle should be repaired. For hypotropia in primary position (Fig 11-7), recession of the ipsilateral inferior rectus muscle can be effective, especially if the muscle is restricted on forced duction testing. Similarly, an incomitant esotropia (with diplopia on side gaze) due to restriction on the medial side may be improved by recession of the ipsilateral medial rectus muscle.
Initially, hypertropia due to weakness of the inferior rectus muscle without entrapment is managed with observation because the weakness may improve with time. If recovery is not complete within 6–12 months of the injury and there is at least a moderate degree of active force, resection of the affected muscle can be performed. If the hypertropia is large, the procedure can be combined with recession of the ipsilateral superior rectus muscle or recession of the contralateral inferior rectus muscle, with or without the addition of a posterior fixation suture (fadenoperation). Transposition of the ipsilateral medial and lateral rectus muscles to the inferior rectus muscle (inverse Knapp procedure) may be necessary for treatment of complete, chronic inferior rectus muscle palsy or when a crippling amount of recession has been necessary to relieve restriction.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.