Radiographic Analysis of Extraocular Muscle Volumetric Changes Following Orbital Decompression in Thyroid-Associated Orbitopathy: Comparison of Nunery Types 1 and 2

PURPOSE: To evaluate the radiographic volume change in extraocular muscles (EOM) following orbital wall decompression for Nunery type 1 and type 2 thyroid-associated orbitopathy (TAO). METHODS: Medical records of 31 orbits in 20 patients undergoing postoperative orbital CT after orbital decompression for TAO were retrospectively reviewed. The patients were divided according to Nunery classifications. A type 1 classification was assigned to patients who had no diplopia and essentially normal versions. A type 2 classification was assigned to patients with restrictive motility loss and diplopia within 20 degrees of the primary position. EOM volumes were determined by the summation of each EOM's cross-sectional areas in the coronal plane of the CT scans and multiplying the sum by the slice thickness. Main outcome measure was a comparison of EOM volume changes between types 1 and 2 TAO and a relationship between EOM volume and change in proptosis. RESULTS: In type 2 TAO, a significant increase in the volume of the medial rectus muscle, lateral rectus, and total EOM was detected postoperatively (p = 0.044, 0.022, 0.049), whereas no significant changes were found in the EOM's volume changes in type 1 TAO. The reduction of proptosis after orbital decompression in type 1 TAO was significantly greater than in type 2 TAO (p = 0.025). A significant positive association was observed between the preoperative EOM volumes and the reduction of proptosis following orbital wall decompression (r = 0.505). CONCLUSIONS: The postoperative EOM volumes following orbital wall decompression was significantly increased in Nunery type 2 patients who had restrictive myopathy.

Eosinophilic Otitis Media: CT and MRI Findings and Literature Review

Eosinophilic otitis media (EOM) is a relatively rare, intractable, middle ear disease with extremely viscous mucoid effusion containing eosinophils. EOM is associated with adult bronchial asthma and nasal allergies. Conventional treatments for otitis media with effusion (OME) or for chronic otitis media (COM), like tympanoplasty or mastoidectomy, when performed for the treatment of EOM, can induce severe complications such as deafness. Therefore, it should be differentiated from the usual type of OME or COM. To our knowledge, the clinical and imaging findings of EOM of temporal bone are not well-known to radiologists. We report here the CT and MRI findings of two EOM cases and review the clinical and histopathologic findings of this recently described disease entity.

Histologic Analysis of the Myotoxic Change by Bupivacaine and Ricin mAb 35 on Extraocular Muscle in Rabbits

PURPOSE: To analyze the acute histologic change of extraocular muscles (EOM) induced by injection of bupivacaine or Ricin mAb 35. METHODS: The superior rectus and inferior rectus of white rabbits were injected with either bupivacaine (0.4 mg in 0.3ml) or Ricin mAb 35 (0.2 micro gram/kg in 0.3 ml). One, two, and four weeks after injection, the rectus muscles were harvested and the post-injection changes were histologically analyzed. RESULTS: Both the orbital and the global layers of EOM showed myotoxic changes induced by bupivacaine and Ricin mAb 35. However, the inflammation and destruction of myofiber by bupivacaine injection were localized to the injection site, whereas changes induced by Ricin mAb 35 were diffuse. Regenerating myofibers with a central nucleus were found at one week after myotoxin injection. Four weeks after injection, the acute changes induced by these two toxins were much recovered with prominent myofiber regeneration. Bupivacaine-induced myotoxic change was more prominent in the global layer in contrast to the more prominent damage in the orbital layer induced by Ricin mAb 35. CONCLUSIONS: We found that EOM have a superb ability to recover from the acute injury induced by bupivacaine or Ricin mAb 35 and that the two myotoxins cause unique damage including the predilection of muscle layers and the duration for which the damage persisted. Further investigation into the functional change during recovery from the myotoxin-induced injury of EOM is needed.