Deep lateral orbital decompression for Graves orbitopathy: a systematic review

Computational Simulation of LAVA Treatment of Thyroid Eye Disease Predicts Soft Tissue Outcome Comparable to Two-Wall Resection

Thyroid eye disease (TED) is a common extrathyroidal manifestation of hyperthyroidism, typically associated with Graves' disease (GD). This condition can cause severe functional limitations as well as significant aesthetic concerns. Treatment for TED patients aims to restore functionality and address aesthetic concerns. Surgical TED treatment is usually performed by orbital wall resection, which effectively decompresses intraorbital tissues and corrects the orbital/ocular disorders. Several different scenarios of surgical TED treatment including one-, two-, and three-wall resections are known. More recently, a new minimally invasive technique, the so-called lateral valgization (LAVA) of the orbital wall, was reported to show promising results comparable to conventional wall resection techniques. Due to the relatively limited data on TED treatment, only a few quantitative investigations of alternative TED surgery scenarios exist. In this feasibility study, we estimate the soft tissue outcome of LAVA treatment using computational simulation. Our experimental results show that the amount of intraorbital tissue released into the extraorbital space by LAVA treatment is comparable with the outcome of two-wall resection. Our computational simulation confirms previously reported isolated clinical findings suggesting that the minimally invasive LAVA approach represents an attractive alternative to conventional wall resection approaches for surgical TED treatment.

Biomechanical analysis of fixation methods for bone flap repositioning after lateral orbitotomy approach: A finite element analysis

OBJECTIVE

In ophthalmic surgery, different materials and fixation methods are employed for bone flap repositioning after lateral orbitotomy approach (LOA), yet there is no unified standard. This study aims to investigate the impact of different fixation strategies on orbital stability through Finite Element Analysis (FEA) simulations of the biomechanical environment for orbital rim fixation in LOA.

METHODS

A Finite Element Model (FEM) was established and validated to simulate the mechanical responses under various loads in conventional lateral orbitotomy approach (CLOA) and deep lateral orbital decompression (DLOD) using single titanium plate, double titanium plates, and double absorbable plates fixation methods. The simulations were then validated against clinical cases.

RESULTS

Under similar conditions, the maximum equivalent stress (MES) on titanium alloy fixations was greater than that on absorbable plate materials. Both under static and physiological conditions, all FEM groups ensured structural stability of the system, with material stresses remaining within safe ranges. Compared to CLOA, DLOD, which involves the removal of the lateral orbital wall, altered stress conduction, resulting in an increase of MES and maximum total deformation (MTD) by 1.96 and 2.62 times, respectively. Under a horizontal load of 50 N, the MES in FEM/DLOD exceeded the material's own strength, with an increase in MES and MTD by 3.18 and 6.64 times, respectively, compared to FEM/CLOA. Under a vertical force of 50 N, the MES sustained by each FEM was within safe limits. Bone flap rotation angles remained minimally varied across scenarios. During follow-up, the 12 patients validated in this study did not experience complications related to the internal fixation devices.

CONCLUSION

Under static or physiological conditions, various fixation methods can effectively maintain stability at the orbitotomy site, and absorbable materials, with their smoother stress transmission properties, are more suited for application in CLOA. Among titanium plate fixations, single titanium plates can better withstand vertical stress, while double titanium plates are more capable of handling horizontal stress. Given the change in the orbital mechanical behavior due to DLOD, enhanced fixation strength should be considered for bone flap repositioning.

Balanced medial-lateral wall vs selective 3-wall orbital decompression for sight-threatening Graves's orbitopathy: a clinical retrospective cohort study from 2016 to 2022

PURPOSE

Although urgent orbital decompression surgery for sight-threatening Graves' orbitopathy unresponsive to available medical treatments continues to evolve, post-operative new-onset or worsened pre-operative strabismus or diplopia remains a significant complication. At present, the optimal surgical technique remains debatable. Here, we sought to compare long-term outcomes after balanced medial-lateral wall versus selective 3-wall decompression as an urgent treatment for unresponsive sight-threatening GO.

METHODS

This retrospective study examined the post-operative outcome of 102 eyes (57 patients) that underwent urgent orbital decompression for sight-threatening GO. Treatment effectiveness was measured by visual acuity, proptosis, perimetry, and strabismus/diplopia, while fundus findings were detected by fundus color photography and optical coherence tomography and followed up for more than 12 months.

RESULTS

Fifty-seven patients (102 orbits) with an average age of 52.7 ± 10.2 years were evaluated. Balanced medial-lateral wall (BMLW-OD) or selective 3-wall decompression(S3W-OD) were performed in 54 and 48 eyes, respectively. Twelve months after orbital decompression, all parameters significantly improved in both groups, including best-corrected visual acuity (BCVA), mean defect of visual field (VF-MD), pattern standard deviation of visual field (VF-PSD), and proptosis (all P < 0.01). However, new-onset esotropia occurred in 25.8% and 3.8% of patients who underwent BMLW-OD surgery or S3W-OD, respectively. Moreover, 6.5% and 38.5% of patients improved after decompression in the medial-lateral wall decompression group and the selective 3-wall decompression group, respectively.

CONCLUSIONS

We demonstrated that S3W-OD provides a lower rate of new-onset strabismus/diplopia as compared with BMLW-OD surgery, while still allowing for satisfactory visual outcomes.

TRIAL REGISTRATION NUMBER

 : NCT05627401. Date of registration: November 25, 2022.

Superior orbital fissure syndrome after deep lateral orbital wall decompression in Graves' ophthalmopathy

PURPOSE

The superior orbital fissure contains cranial nerves III, IV, VI, and V1 with their three branches: frontal, lacrimal, and nasociliary. Superior orbital fissure syndrome (SOFS) is rare and can occur as a result of compression of these nerves due to trauma, bleeding, or inflammation in the retrobulbar space, but no cases of SOFS after deep lateral orbital wall decompression (DLOWD) have been reported. The aim of this paper is to describe this pathology, its possible causes, management, and outcome.

METHODS

Retrospective study of 575 DLOWD in patients with disfiguring exophthalmos due to Graves' ophthalmopathy performed in our hospital between 2010 and 2023. Three cases of postoperative SOFS were identified based on clinical presentation, history, physical examination, and radiological study. All patients were observed for a minimum of 12 months.

RESULTS

SOFS was diagnosed with the presence of ophthalmoplegia, ptosis, fixed and dilated pupils, hypo/anesthesia of the upper eyelid and forehead, loss of corneal reflex, and no loss of vision after DLOWD. Fractures, edema, and hemorrhages were excluded. They were treated with high-dose intravenous steroids and the patients recovered completely.

CONCLUSIONS

DLOWD challenges orbital surgeons because it requires removing bones near the globe or neurovascular structures. SOFS may occur due to the proximity and increased pressure on these structures.

[Interdisciplinary Management of Orbital Diseases]

Diagnosis and therapy of orbital diseases is an interdisciplinary challenge, in which i.e. otorhinolaryngologists, ophthalmologists, radiologists, radiation therapists, maxillo-facial surgeons, endocrinologists, and pediatricians are involved. This review article describes frequent diseases which both, otolaryngologists and ophthalmologists are concerned with in interdisciplinary settings. In particular the inflammatory diseases of the orbit including orbital complications, autoimmunological diseases of the orbit including Grave´s orbitopathy, and primary and secondary tumors of the orbit are discussed. Beside describing the clinical characteristics and diagnostic steps the article focusses on the interdisciplinary therapy. The review is completed by the presentation of most important surgical approaches to the orbit, their indications and possible complications. The authors tried to highlight the relevant facts despite the shortness of the text.

Initial implementation of surgical guide design utilizing digital medicine for lateral orbital decompression surgery

This study aimed to assess the feasibility of utilizing a surgical guide, designed through digital medical technology, in lateral orbital decompression surgery. METHODS: In total, 18 patients with thyroid-associated ophthalmopathy (TAO), who underwent orbital balance decompression surgery at the Affiliated Eye Hospital of Nanchang University between September 2018 and August 2022, were included. Orbital CT scanning was performed on all patients with TAO, and Mimics 21.0 software was used to reconstruct a three-dimensional model of the orbit based on the CT data. The osteotomy guide plate for lateral orbital decompression surgery was designed using 3-matic 13.0 software, adhering to the criteria of surgical effectiveness and safety. The surgical positioning guide was designed using Geomagic Wrap 21.0. Once printed, the surgical guide was sterilized with low-temperature plasma and applied during surgery. Of the nine patients treated using a surgical navigation system, three cases experienced cerebrospinal fluid leakage complications during the procedure, and two exhibited inadequate bone removal along the lateral wall. In contrast, among the nine patients treated with surgical guides, no intraoperative cerebrospinal fluid leakage or evidence of insufficient lateral wall bone removal was observed, highlighting a statistically significant distinction between the two cohorts (p = 0.046). Postoperative improvements were notable in best-corrected visual acuity (BCVA) and exophthalmos for patients afflicted with extremely severe TAO. The surgical guide, designed with digital medical technology, has been shown to be an effective and secure auxiliary tool in lateral orbital decompression surgery. It not only aids in reducing the incidence of intraoperative complications, but also enhances the accuracy and safety of surgery. These improvements offer robust support for continued exploration in this field within clinical practice.

Impact of sphenoid trigone size and extraocular muscle thickness on the outcome of lateral wall orbital decompression for thyroid eye disease

BACKGROUND

To retrospectively review lateral wall orbital decompression for thyroid eye disease (TED) and to evaluate pre-operative CT scans to analyse the variation in proptosis reduction.

METHODS

Consecutive lateral wall orbital decompressions performed by a single surgeon were retrospectively reviewed. Pre-operative CT scan features and post-operative proptosis reduction were analysed. The sphenoid trigone cross-sectional areas were summed and multiplied by the slice thickness to yield bone volume. Cumulative extraocular muscle thickness was calculated by combining the maximum thickness of the four recti. "Trigone volume" and "cumulative muscle thickness" were correlated with proptosis reduction at 3 months post-surgery.

RESULTS

Out of 73 consecutive lateral wall orbital decompressions, 17 orbits had prior endonasal medial wall orbital decompression. In the remaining 56 orbits, the mean pre-operative and post-operative proptosis were 24.3 ± 1.6 mm and 20.9 ± 2.3 mm respectively. The proptosis reduction ranged from 1 to 7 mm (mean of 3.5 mm ± 1.3 (p < 0.001)). Mean sphenoid trigone volume was 895 ± 434.4 mm3. The mean cumulative muscle thickness was 20.4 ± 5 mm. The correlation coefficient between muscle thickness and proptosis reduction was - 0.3 and was statistically significant (p = 0.043). The correlation coefficient between sphenoidal trigone volume and proptosis reduction was 0.2 (p = 0.068). With a multivariate analysis, the coefficient of efficient of regression for muscle thickness was - 0.007 (p = 0.42) and the coefficient of regression for trigone volume was 0.0 (p = 0.046).

CONCLUSION

Proptosis reduction following lateral wall orbital decompression can be variable. Extraocular muscle thickness had a significant correlation with the outcome, with greater proptosis reduction in orbits with thin muscles. The sphenoidal trigone size had a weak correlation with decompression outcome.

The effect of rim-off deep lateral orbital decompression on the lateral rectus shape and oculomotor balance

PURPOSE

The purpose of the study was to measure the effect of rim-off deep lateral decompression for Graves orbitopathy on the lateral rectus muscle path and oculomotor balance.

METHODS

Retrospective analysis of the medical records and pre- and postoperative computed tomography scans of 34 orbits of 23 patients who underwent deep lateral decompression alone. The oculomotor balance of these 23 patients was measured with the alternate cover test and prisms before and after surgery. Bezier functions were used to measure the postoperative path of the lateral rectus in all decompressed orbits.

RESULTS

Deep lateral decompression induced a curvilinear deformation of the lateral rectus. There was no significant correlation between the position of the point of maximum muscle displacement and the size of the residual lateral wall. The changes in the lateral rectus path had no adverse effects on the oculomotor balance of the patients.

CONCLUSIONS

The location of the curvilinear deformation of the lateral rectus does not depend on the residual segment of the lateral wall. The changes of the lateral rectus path have no deleterious effect on the oculomotor balance.

Pneumatization of the Greater Wing of Sphenoid Utilization for Lateral Wall Decompression

The goal of orbital decompression for thyroid orbitopathy is to expand the orbital space for the contents with various techniques described. Deep lateral wall decompression is a procedure that expands the orbit by removing bone from the greater wing of sphenoid however its effectiveness is dependent on the volume of bone removed. Pneumatization of the greater wing of sphenoid is defined as an extension of the sinus beyond the VR line (a straight line crossing the medial edges of the vidian canal and the foramen rotundum) which is a demarcation between the sphenoid body and the lateral parts of the sphenoid bone, including the greater wings and pterygoid process. We present a case of complete pneumatization of the greater wing of sphenoid affording a greater volume of bony decompression in a patient with significant proptosis and globe subluxation as a result of thyroid eye disease.

Effect of Rim-Off Deep Lateral Orbital Decompression on Interpalpebral Fissure Shape

PURPOSE

The purpose of this study is to compare the palpebral fissure shape after rim-off deep lateral decompression with and without restoration of the lateral orbital rim.

METHODS

Retrospective cross-sectional quantitative analysis of the palpebral fissure images of 17 patients (25 eyes) who underwent rim-off deep lateral orbital decompression without repositioning of the rim (G1) and of 20 patients (34 eyes) operated with rim restoration. Quantification of palpebral fissure images included MRD 1 and MRD 2 , two lateral mid-pupil lid margin (MPD) distances, the width of the palpebral fissure, and the height and shape of the lateral canthus.

RESULTS

Proptosis reduction did not differ significantly between G1 and G2. In both groups, decompression reduced the mean values of the MRD 1 and MRD 2 , the lateral height of the upper eyelid, and the height and angle of the lateral canthus. The palpebral fissure width and lateral height of the lateral lower eyelid were not affected. There was no significant difference between the mean changes of G1 and G2. Multivariate analysis showed that the lateral canthus decrease was correlated with changes in MRD 1 and MRD 2 .

CONCLUSIONS

Small changes in palpebral fissure shape after deep lateral decompression are not dependent on the presence or absence of the lateral rim.

Update on the surgical management of Graves' orbitopathy

Graves' orbitopathy (GO) is a complex autoimmune disorder of the orbit that causes the eye to appear disfigured. GO is typically associated with Graves' disease, an inflammatory autoimmune condition that is caused by thyrotropin receptor autoantibodies. Although our knowledge of the pathophysiology of GO has improved, its exact pathogenesis remains unclear. Some patients suffer from disfigurement, double vision, and even vision loss rather than hyperthyroidism. The disease severity and activity prompt different treatments, as the signs of GO are heterogeneous, so their management can be very complex. Despite medical advances, the first-line treatment for moderate-to-severe active GO is still glucocorticoids, while surgery can be critical for the treatment of chronic inactive GO. Surgery is sometimes required in the acute phase of the disease when there is an immediate risk to vision, such as in dysthyroid optic neuropathy. Most surgeries for GO are rehabilitative and subdivided into three categories: decompression, strabismus repair, and lid surgery. This review is a basic overview of the field, with up-to-date knowledge of the surgical techniques for GO. We review and summarize recent literature on the advances in surgery for GO to provide up-to-date insights on the optimal surgical treatment for GO.

Effect of the lateral wall valgisation in the treatment of patients with endocrine orbitopathy

Orbital decompression is an established procedure used to correct exophthalmos that results from excess orbital soft tissue. This study aimed to explore a new minimally-invasive technique that features three-dimensional planning and patient-specific implants for lateral valgisation (LAVA) of the orbital wall. We analysed the outcomes of this procedure in nine endocrine orbitopathy (EO) patients (32-65 years of age with a mean clinical activity score of 4.3) who underwent this procedure between 2021 and 2022, including seven patients diagnosed with dysthyroid optic neuropathy. The impact of LAVA and wall resection on orbital areas, volumes, Hertel values, visual acuity, and new-onset diplopia was determined. Among our results, we found that LAVA and resection of 18 orbital walls resulted in significant enlargement of the orbital volume from a preoperative mean of 30.8 ± 3.5 cm³ to a mean of 37.3 ± 5.8 cm³ postoperatively (mean difference, 6.2 ± 1.8 cm³; p < 0.001); this procedure also resulted in a significant reduction in the mean Hertel value, from 28.7 ± 1.9 mm to 20.0 ± 1.9 mm (mean difference, 8.7 ± 1.9 mm; p < 0.001). The procedure resulted in visual acuity declined in three patients (33.3 %) with reductions from 0.25 to 0.125, 0.8 to 0.125, and 1.2 to 0.7, respectively. No new diplopia occurred postoperatively, however, our study included five patients with preoperative diplopia that did not improve postoperatively and required additional surgical intervention. Similarly, four patients required supplemental eyelid surgery. In conclusion, our study suggests the effects of the LAVA with the partial floor resection seems to be effective, which provides a substantially improved outcome for patients undergoing surgical treatment of EO via the use of double navigation and piezosurgical methods.

3-D cephalometry of the the orbit regarding endocrine orbitopathy, exophthalmos, and sex

Purpose

This study aimed at evaluating the orbital anatomy of patients concerning the relevance of orbital anatomy in the etiology of EO (endocrine orbitopathy) and exophthalmos utilizing a novel approach regarding three-dimensional measurements. Furthermore, sexual dimorphism in orbital anatomy was analyzed.

Methods

Orbital anatomy of 123 Caucasian patients (52 with EO, 71 without EO) was examined using computed tomographic data and FAT software for 3-D cephalometry. Using 56 anatomical landmarks, 20 angles and 155 distances were measured. MEDAS software was used for performing connected and unconnected t-tests and Spearman´s rank correlation test to evaluate interrelations and differences.

Results

Orbital anatomy was highly symmetrical with a mean side difference of 0.3 mm for distances and 0.6° for angles. There was a small albeit statistically significant difference in 13 out of 155 distances in women and 1 in men concerning patients with and without EO. Two out of 12 angles showed a statistically significant difference between female patients with and without EO. Regarding sex, statistically significant differences occurred in 39 distances, orbit volume, orbit surface, and 2 angles. On average, measurements were larger in men. Concerning globe position within the orbit, larger distances to the orbital apex correlated with larger orbital dimensions whereas the sagittal position of the orbital rim defined Hertel values.

Conclusion

In this study, little difference in orbital anatomy between patients with and without EO was found. Concerning sex, orbital anatomy differed significantly with men presenting larger orbital dimensions. Regarding clinically measured exophthalmos, orbital aperture anatomy is an important factor which has to be considered in distinguishing between true exophthalmos with a larger distance between globe and orbital apex and pseudoexophthalmos were only the orbital rim is retruded. Thus, orbital anatomy may influence therapy regarding timing and surgical procedures as it affects exophthalmos.