[Proton spin tomography of the orbit in post-traumatic motility disorders]

To analyse the value of MRI for the assessment of posttraumatic disturbances of eye motility.

We analysed retrospectively the results of 38 MR examinations of the orbit in 31 patients with posttraumatic motility impairment with preserved visus. 18 patients underwent MRI preoperatively. From this group 5 patients were additionally examined postoperatively. Another 5 patients who had not been examined prior to surgery were controlled postoperatively. Hence, a total of 10 patients with persisting disturbances was examined postoperatively. 8 patients who underwent MRI were not treated by surgery because of only minor disturbances. In all patients conventional radiography of the orbit was performed prior to MRI. Additional CT imaging was carried out in 12 patients.

In 18 patients examined preoperatively we found displacement of orbital fat tissue, displacement and entrapment of orbital muscles, swelling of muscles and oedema in retrobulbar fat tissue. 10 patients from the postoperative group exhibited remaining prolapsed fat tissue, oedema in fat tissue and/or swelling of muscles. 8 patients had only small soft tissue changes which did not require surgery.

Since it can image soft tissue precisely, MRI provides the decisive information in the assessment of motility impairment of the eye. In case of isolated orbital fracture with motility impairment, CT is not absolutely necessary for surgical therapy.