Anatomy of the Superior Border of the Lateral Orbital Wall: Surgical Implications in Deep Lateral Orbital Wall Decompression Surgery

[The significance of surgical anatomy in lateral orbital wall decompression]

The article reviews data on the anatomical and topographic features of the lateral wall in the context of performing orbital surgery and presents a description of the surgical areas of the lateral wall that are most important for increasing the volume of the orbit: the lacrimal keyhole, the sphenoid door jamb, and the basin of the inferior orbital fissure. Particular attention is given to the topographic anatomy of the sphenoid door jamb as the most promising area for orbital decompression and transorbital access to the skull base.

Deep lateral orbital decompression for Graves orbitopathy: a systematic review

PURPOSE

To systematically review the literature on the deep lateral orbital decompression (DLD).

METHODS

The authors searched the MEDLINE, Lilac, Scopus, and EMBASE databases for all articles in English, Spanish, and French that used as keywords the terms orbital decompression and lateral wall. Two articles in German were also included. Data retrieved included the number of patients and orbits operated, types of the approach employed, exophthalmometric and horizontal eye position changes, and complications. The 95% confidence intervals (CI) of the mean Hertel changes induced by the surgery were calculated from series with 15 or more data.

RESULTS

Of the 204 publications initially retrieved, 131 were included. Detailed surgical techniques were analyzed from 59 articles representing 4559 procedures of 2705 patients. In 45.8% of the reports, the orbits were decompressed ab-interno. Ab-externo and rim-off techniques were used in 25.4% and 28.8% of the orbits, respectively. Mean and 95% CI intervals of Hertel changes, pooled from 15 articles, indicate that the effect of the surgery is not related to the technique and ranges from 2.5 to 4.5 mm. The rate of new onset of diplopia varied from zero to 8.6%. Several complications have been reported including dry eye, oscillopsia, temporal howling, lateral rectus damage, and bleeding. Unilateral amaurosis and subdural hematoma have been described in only one patients each.

CONCLUSIONS

The low rate of new-onset diplopia is the main benefit of DLD. Prospective studies are needed to compare the rate of complications induced by the 3 main surgical techniques used.

Orbital Decompression for Thyroid-Related Orbitopathy During the Quiescent Phase

PURPOSE

To describe historical and modern surgical approaches to orbital decompression in patients with thyroid-related orbitopathy in the quiescent phase.

METHODS

A literature review of published techniques using the National Institutes of Health PubMed database.

RESULTS

Historically, orbital decompression has been accomplished via transantral, transcranial, transnasal, and orbital approaches. Current techniques use predominately periocular incisions to achieve effective decompression and proptosis reduction. Based on exophthalmometry and desired proptosis reduction, the authors propose a graded surgical approach to decompression for thyroid orbitopathy beginning with fat reduction, followed by deep lateral orbit via a superior eyelid crease incision, then medial wall by retro-caruncular approach, then posterior medial orbital floor either via transconjunctival or swinging eyelid approach, and finally with lateral orbital rim removal by superior eyelid crease incision as needed. These approaches can result in a range of proptosis reduction of up to 10 mm.

CONCLUSIONS

A structured approach to orbital decompression results in predictable and effective outcomes in proptosis reduction.

Ethnic variation in deep lateral orbital anatomy and its implications on decompression surgery

AIM

To describe differences in the deep lateral orbital wall (specifically, trigone) between Chinese, Malay, Indian and Caucasian subjects Methods: Single-centre retrospective Computed Tomogram (CT)-based study; 20 subjects of each ethnicity were used from existing databases, matched for gender, average age and laterality. Subjects below 16 years of age were excluded. DICOM image viewing software CARESTREAM Vue PACS (Carestream Health Inc., USA) and OsiriX version 7.5 (Pixmeo., Switzerland) were used to measure deep lateral wall length, thickness and volume, as well as orbital depth and statistical analyses performed using Statistical Package for Social Sciences version 21 (IBM, USA).

RESULTS

In each group, there were 12 males (60%) and average age was not significantly different (p = 0.682-0.987). Using Chinese subjects as a reference, in Chinese, Malay, Indian and Caucasian subjects, mean trigone thickness was 13.68, 14.02, 11.60 (p < 0.001) and 13.80 mm, curved total wall length 45.23, 42.29 (p = 0.048), 41.91 (p = 0.020) and 45.00 mm, curved trigone length 23.03, 22.61, 17.19 (p = 0.011) and 18.76 mm (p = 0.030) and trigone volume 3120.97, 3221.01, 1613.66 (p < 0.001), 2498.46 mm³ (p = 0.059) respectively. Similarly, perpendicular orbital depth was 27.54, 24.97, 22.12 (p = 0.001) and 25.93 mm and diagonal orbital depth was 34.19, 33.27, 29.48 (p = 0.01) and 34.63 mm respectively.

CONCLUSIONS

Indian and, to a lesser extent, Caucasian subjects have smaller trigones compared to their Chinese and Malay counterparts. Indian subjects also have shallower orbits and due care should be taken during decompression surgery.

[Potentials of intraoperative navigation during balanced orbital bony decompression in thyroid eye disease (preliminary results)]

Precise instrument localization is of great importance in orbital decompression surgery. Different navigation systems were designed to fulfill this task and gained wide acceptance.

AIM

to describe principal features and determine advantages of intraoperatively navigated orbital bony decompression.

MATERIAL AND METHODS

Data on orbital decompression surgery performed with or without intraoperative image guidance is presented. Each time two surgeons were involved - an ophthalmologist (lateral wall decompression) and otolaryngologist (medial wall decompression).

RESULTS

In lateral wall decompression, electromagnetic navigation was mostly used to enlarge the created bone window upward and backward, which is particularly challenging in case of bone thinning in the posterior part of its inner rim. In transethmoidal decompression, the image guidance allowed a more extensive removing of the greater sphenoid wing as well as the posterior medial wall where it joins the lateral wall of the sphenoid sinus. As shown by MSCT, lateral rectus muscle dislocation into the created bone window was more significant in navigated procedures.

CONCLUSION

This preliminary data convincingly shows advantages and potentials of the use of electromagnetic navigation in orbital decompression surgery, especially, for optic neuropathy in thyroid eye disease patients.

Anatomy of deep lateral and medial orbital walls: implications in orbital decompression surgery

BACKGROUND

Isolated deep lateral and combined medial orbital wall decompressions (balanced decompression) are well accepted for treatment of disfiguring proptosis and compressive optic neuropathy in patients with Graves' orbitopathy. However, cerebrospinal fluid leakage and/or optic nerve injury occasionally occur during these operations.

PURPOSE

To describe the anatomy of the deep lateral and medial orbital walls and its surgical implications in orbital decompression.

METHODS

We reviewed literature on the anatomy of the deep lateral and medical orbital walls. In addition, we performed cadaver dissection and computed tomographics studies to illustrate the anatomy.

RESULTS

We provided an anatomical overview and elucidated the detailed surgical anatomy of the posterior and superior borders of the deep lateral orbital wall, the posterior and accessory ethmoidal foramina, and the frontoethmoidal suture.

CONCLUSIONS

The anatomy of the deep lateral and medical orbital walls presented here will warrant safe and confident performance of orbital decompression surgery.