The Evolution of Orbital Decompression Surgery

Orbital decompression surgery has been used in the management of thyroid eye disease (TED) and other orbital pathologies to address proptosis and vision-threatening complications for more than 100 years (1). Since the surgery was first described, advancements in techniques have refined the procedure, which highlights a growing understanding of orbital anatomy and the desire for less invasive and morbid interventions. In this article, we look at the historical milestones and technical advancements that have led the field to its current state.

Specialty involvement

Throughout the years, orbital decompression surgery has been shaped by contributions from multiple surgical specialties. The earliest recorded approach to orbital decompression was described in 1889 by Rudolf Ulrich Krönlein, a Swiss neurosurgeon, who introduced the lateral orbitotomy for the removal of orbital tumors (1). In 1890, Dollinger adapted this technique, marking the first application of this procedure for TED (2).

Over 30 years later, Hirsch, an otolaryngologist looking to treat a case of “malignant exophthalmos,” performed the first inferior orbital wall decompression via a transnasal approach (3). Two years later, Naffziger further expanded the surgical options available for orbital decompression by using the transcranial approach to remove the roof and lateral wall via a craniotomy approach (4). This innovation was followed, in 1939, by Kistner performing the first medial wall decompression through the fronto-ethmoidal sinus, using a method that had previously been proposed by Sewall in 1936 (1).

Another significant advancement came with Walsh and Ogura’s transantral approach to decompress the inferior and medial orbital walls (5). This technique became the mainstay of orbital decompression for many years, allowing excellent visualization of the floor and inferior portion of the medial wall while avoiding visible cutaneous scars (6). In the 1990s, the introduction of endoscopic approaches further revolutionized medial orbital wall decompression by enabling sinus-based access with less morbidity (7).

Orbital decompression surgery gradually transitioned into the domain of ophthalmology in the 1990s. Around the same time that endoscopic approaches were introduced, transorbital decompression of the deep lateral wall gained traction, with Goldberg popularizing techniques that targeted deeper bone structures without requiring craniotomy (7).

Orbital fat decompression emerged in the 1990s, with Olivari pioneering selectively removing extraconal and intraconal fat to more easily achieve effective decompression without significant bony alterations (8). This approach, later refined by Kazim and Trokel, has now become a critical component of modern-day orbital surgery (9). Typically, the approach results in the removal of 5.5 to 6.5 cc of total fat, though techniques that prioritize intraconal fat removal alone tend to extract smaller volumes of around 3.5 to 4.5 cc (8, 10, 11, 12, 13).

The “my way” approach

As more approaches began to be described and popularized, orbital decompression surgery literature gradually shifted towards a “my way is the correct way” approach. A number of specific techniques for incision and approach reached for the same goal – effective and safe orbital decompression.

Lateral wall

Lateral wall decompression has seen significant refinements in incision techniques, progressing from historical Krönlein and bi-coronal approaches to less invasive methods, such as lateral eyelid crease (14), lateral canthal splitting (15), and swinging eyelid techniques, all of which are more widely used today (16).

Lateral wall bone removal strategies have similarly progressed since Naffziger introduced traditional transcranial methods in the 1930s, giving way to the development of several less invasive transorbital approaches (4). The transorbital ab interno approach to the deeper bone of the sphenoid has since been popularized by Goldberg (17), while Rose described an approach via removal of the lateral orbital rim, or creation of a lateral orbital window (18). Additionally, an ab externo approach involving access through the temporalis fossa, without a marginotomy, has also been described (19).

Finally, a transconjunctival swinging eyelid incision has also been used to access the lateral wall and subsequently remove the deep sphenoid bone (20). Lateral wall approaches now often incorporate the removal of bone to the diploic space with extension into the inferotemporal region for additional decompression. With bone removal refined to target specific areas – such as the deep sphenoid, orbital rim, lateral wall, and zygoma – a significant proptosis reduction, with a reduced risk of inducing new onset diplopia in primary gaze removal, can be achieved.

Orbital floor

Orbital floor decompression has similarly evolved from aggressive bone removal to more conservative strategies aimed at minimizing complications like enophthalmos and diplopia. Initial transcutaneous approaches often resulted in ectropion and lid retraction, and these methods have now been largely replaced by transconjunctival approaches. These approaches involve making an incision on the palpebral conjunctival surface of the lower eyelid posterior to the tarsus, offering better cosmetic outcomes for patients. Preseptal or postspetal dissection is now commonly used to access the floor for intraorbital nerve sparing surgery. Bone removal strategies have shifted from complete removal to more conservative approaches, focusing on removal medial to V2 and confined to the posterior half of the floor to prevent complications such as sunsetting globe deformity.

Medial wall

Medial wall decompression has perhaps seen the most dramatic evolution. Historically, techniques such as the Lynch incision, which involves a curvilinear incision midway between the medial canthus and nasal bridge, were used to access the medial orbit. Before that, an even more invasive coronal approach, which involved making an incision in the scalp at the hairline to allow access to all four orbital walls, was used for medial transorbital exposure. However, due to well described complications and prominent scarring created by these two approaches (21, 22), both incision techniques have largely fallen out of favor.

The less invasive transcaruncular approach provides similar access to the medial wall without visible scarring. As such, it has largely replaced both previous techniques for transorbital access. Much like the transcaruncular approach, the transantral approach – pioneered by Walsh and Ogura (5) – can provide access to the medial orbit without creating an external scar. In the transantral approach, an incision is made in the upper gingivobuccal sulcus (Caldwell-Luc incision), entering the maxillary sinus and accessing the orbital floor and medial wall through the roof of the sinus. Despite its advantages, risks such as paresthesias are common, and rarer complications, including oroantral and gingivolabial fistulas and devitalized teeth, are seen in a small percentage of cases.

The transnasal endoscopic approach accesses the medial orbit through the nasal cavity. The extent of bone removal using the transnasal approach has similarly evolved over time. Anteriorly, the dissection typically extends to the posterior lacrimal crest, with some approaches extending to the anterior lacrimal sac but avoiding the anterior ethmoidal foramen. Posteriorly, bone is typically removed up to the anterior wall of the sphenoid sinus, though it may extend to the optic canal, particularly in cases involving dysthyroid optic neuropathy. Superiorly, dissection is often carried out to the frontoethmoidal suture.

An “every wall, every way” approach

Today, orbital decompression can be approached through any number of incisions, wall combinations, and degrees of fat removal. The “my way” approach to orbital decompression has provided wide-ranging data on technique, and it has become clear over time that there are many effective ways to decompress the orbit.

Incisions have become more refined, with some now being virtually invisible. The medial wall can be accessed through a transcaruncular or endonasal approach, and the lateral wall through eyelid crease or canthal incisions, each being very well hidden or virtually invisible.

The field has also shifted toward safer techniques for incision and bone removal. The ab interno technique for lateral decompression has resulted in fewer complications, such as oscillopsia and late canthal dystopia. Diplopia and sunsetting can be minimized in medial orbital decompression by sparring the anterior floor and strut.

Surgical technique pearls

In addition to the importance of surgical technique, the position of the surgeon can improve visualization and instrumentation in the orbit. In lateral decompression, the surgeon may need to position on the patient’s contralateral side, with the patient’s head tilted toward the surgeon for optimal visualization of the bony anatomy. With better visualization and maneuvering of the drill from this position, the diploic space can be completely bowled out to the posterior table with extension into the inferotemporal area, leading to greater decompressive effect. The deep bone over the middle cranial fossa can also be removed, exposing the temporal dura for an additional 1mm of proptosis reduction without the onset of diplopia in primary position (23). Additionally, orbital fat decompression in the anterior inferolateral region can be effective and safe, adding to the overall decompression effect.

Conclusion

As surgical techniques continue to refine, we may see a shift in how orbital decompression surgery is approached and presented. A transition towards a more delineated and comprehensive classification of the boney anatomy targeted in orbital decompression, rather than the simple “four wall” paradigm, may better capture the nuances of contemporary decompression techniques. Future research may focus on defining these anatomical zones more precisely for easier comparison and trainee understanding of decompression techniques presented in the literature. As the field and surgical technology progresses, there will continue to be evolution in surgical approach and technique, in the hopes of improving TED symptomology and further minimizing complications.

This work was previously presented at the 2024 European Society of Ophthalmic Plastic and Reconstructive Surgery Meeting.