Orbital decompression surgery is performed in patients with Graves’ orbitopathy to treat dysthyroid optical neuropathy (DON) and reduce disfiguring proptosis. The intended proptosis reduction can deviate from the postoperative result and changes of motility with consecutive diplopia can occur. We performed a retrospective study to identify anatomical factors in computed tomography (CT), which influence the surgical effect and postoperative ocular motility and diplopia. Pre- and postoperative CT-scans of 125 eyes of 68 patients, who mainly underwent a balanced orbital decompression for disfiguring proptosis (≥18mm Hertel Index), have been analyzed. Proptosis, ductions, misalignment and diplopia were assessed before and after surgery. Medial and lateral orbital wall length, conus angle, depth of ethmoidal sinus, orbital surface, length of medial and orbital defect, depth of tissue prolapse and horizontal muscle diameters were analyzed in CT scans before and after surgery. With linear regression and multivariate analyses these parameters have been correlated with postoperative proptosis, abduction deficit, deviation and binocular single vision (BSV). Proptosis could be reduced by 5.3±2mm. Patients with 5mm reduction (13% vs. 56%, p = 0.02). Multiple linear regression showed a significant correlation between tissue prolapse and depth of the ethmoidal sinus as well as age (p<0.001, r = 0.71). Proptosis reduction could not be predicted by tissue prolapse, defect length or depth of ethmoidal sinus. The abduction deficit correlated significantly with tissue prolapse and orbital surface area (p<0.001, r = 0.37) but not with the horizontal muscle diameter. We were able to show that orbital morphology influences the outcome of balanced orbital decompression surgery in terms of proptosis reduction and motility. However, the rather low coefficients of correlation show that the surgical outcome cannot be predicted with simple CT measurements, although risk factors for postoperative abduction deficit could be found. Therefore, preoperative planning should consider especially the orbital surface area and depth of ethmoidal sinus. Patients should be informed about the higher risk of diplopia with higher proptosis reduction.

Purpose: The aim of the study was to identify possible risk factors for new onset diplopia in 20° of primary position (NOD PP) after orbital decompression. A predisposition for NOD has been established for patients with pre-existing diplopia in secondary gaze; therefore, the authors focused on patients without preoperative diplopia. Methods: Retrospective chart review of patients who underwent balanced orbital decompression between 2012 and 2019 due to Graves orbitopathy at the authors’ institution. Exclusion criteria were incomplete clinical data set, revision surgery, and medial or lateral decompression only. The following clinical parameters were evaluated preoperatively and postoperatively: Hertel exophthalmometry, objective measurement of misalignment using the prism-cover-test, assessment of the field of binocular single vision, and measurement of monocular excursions. In addition, the diameter of the extraocular eye muscles was measured in all preoperative CT scans. Results: We included 327 patients (612 orbits), 126 patients (242 orbits) had no preoperative diplopia. In patients with NOD PP (34%, n = 43/126), enlargement of the medial rectus muscle and restriction of abduction and elevation were significantly more frequent than in patients with no NOD PP. The degree of exophthalmos decrease positively correlated with postoperative squint angle. Conclusion: We were able to identify the diameter of the medial rectus muscle, restriction of abduction, and elevation as well as an extensive reduction of exophthalmos as risk factors for NOD PP in patients with no preoperative diplopia.

Introduction: Different minimally invasive surgical approaches to the orbit allow individualized bone resection to reduce proptosis and decompress the optic nerve in patients with Graves’ orbitopathy (GO). This study aims to compare piezosurgery to an oscillating saw used to resect bone from the lateral orbital wall. Methods: In a retrospective study, we analyzed balanced orbital decompressions performed on 174 patients (318 cases) with GO. An oscillating saw was used in 165 cases (saw group) and piezosurgery in 153 cases (piezo group). Peri- and postoperative complications, reduction of proptosis, new onset of diplopia and improvement of visual acuity in cases of pre-operative optic nerve compression were analyzed. Results: We observed no significant differences in the surgical outcome between the two groups. Proptosis reduction was 4.6 mm in the saw group (p < 0.01) and 5.3 mm in the piezo group (p < 0.01). Intraoperative handling of the piezosurgery device was judged superior to the oscillating saw, due to soft tissue conservation and favourable cutting properties. Duration of the surgery did not differ between the groups. No serious adverse events were recorded in both groups. Conclusion: The application of piezosurgery in orbital decompression is more suitable than an oscillation saw due to superior cutting properties such as less damage to surrounding soft tissue or a thinner cutting grove.

Purpose: To determine the outcome after orbital decompression using a graduated technique, adapting the surgical technique according to individual patients’ disease characteristics. Methods: We retrospectively examined the postoperative outcome in patients treated with a graduated balanced orbital decompression regarding reduction of proptosis, new onset diplopia and improvement in visual function. 542 patients (1018 orbits) were treated between 2012 and 2020 and included in the study. Clinical examinations including visual acuity, exophthalmometry (Hertel) and orthoptic evaluation were performed preoperatively and at minimum 6 weeks postoperatively. Mean follow-up was 22.9 weeks. Results: Mean proptosis values have significantly decreased after surgery (p < 0.01). In 83.3% of the patients Hertel measurement normalized (≤ 18 mm) after surgery, New onset diplopia within 20° of primary position occurred in 33.0% of patients, of whom 16.0% had preoperative double vision in secondary gaze. Patients suffering from dysthyroid optic neuropathy (DON) had a significant increase in visual acuity (p < 0.01). Conclusion: We demonstrated that individually adapted graduated orbital decompression successfully improves key disease parameters of Graves’ orbitopathy with low morbidity.

Whether the origin of severe hearing loss in Refsum’s syndrome is caused by cochlear impairment or retrocochlear degeneration remains unclear. This case report aims to investigate hearing performance before and after cochlear implantation to shed light on this question. Also, identification of new mutations causing Refsum’s syndrome would be helpful in generating additional means of diagnosis. A family of 4 individuals was subjected to genetic testing. Two siblings (56 and 61 years old) suffered from severe hearing and vision loss and received bilateral cochlear implants. Genetic analysis, audiological outcome, and clinical examinations were performed. One new mutation in the PHYH gene (c.768del63bp) causing Refsum’s disease was found. Preoperative distortion product otoacoustic emissions (DPAOEs) were absent. Postoperative speech perception in Freiburger speech test was 100% for bisyllabic words and 85% (patient No. 1) and 65% (patient No. 2), respectively, for monosyllabic words. Five years after implantation, speech perception remained stable for bisyllabic words but showed decreasing capabilities for monosyllabic words. A new mutation causing Refsum’s disease is presented. Cochlear implantation in case of severe hearing loss leads to an improvement in speech perception and should be recommended for patients with Refsum’s disease, especially when the hearing loss is combined with a severe loss of vision. Decrease of speech perception in the long-term follow-up could indicate an additional retrocochlear degeneration.