Lateral orbitotomy is traditionally used for approaching of intraconal cavernous hemangioma, as this gives a wide surgical exposure. However, it is a time consuming major procedure requiring a visible skin incision, a bone flap creation and reconstruction and a risk of trauma to the lateral rectus muscle with subsequent myopathy. Additionally, it is difficult to approach lesions medial to the optic nerve using this technique. (6)
Transcranial approach is still used by neurosurgeons for the approach of intraconal space in spite of high rate of morbidity including visual loss, ptosis, orbital hemorrhage, postoperative subdural hematoma and meningitis. This technique should be reserved for lesions at the orbital apex or those with an intracranial extension. (7)
Since its introduction in 1980, transconjunctival anterior orbitotomy was used for approach of the intraconal space. It is not time consuming, gives better cosmesis compared to lateral orbitotomy with a low risk of optic nerve affection and it can be tailored according to the location of the lesion. However, transconjunctival orbitotomy technique was under-utilized because of the narrow space it presents, inadequate exposure of deep intraconal lesions and subsequent postoperative complications. (8)
For achievement of better results with transconjunctival approach, the anterior border of the lesions should be close to the posterior pole of the globe, because deeper lesions close to the orbital apex will be masked by the orbital fat and therefore more difficult to handle. (9)
In this study we used the transconjunctival approach for intraconal cavernous hemangioma where the mass was present lateral, above and below the optic nerve. All tumors were successfully extracted with the aid of the cryoprobe that provided a good grip to the mass, facilitating removal without affection of the surrounding structures. In this study three cases showed postoperative lateral rectus myopathy that improved spontaneously within six months, one case showed postoperative retrobulbar hemorrhage that did not compress the optic nerve and improved spontaneously, and four cases showed subconjunctival hemorrhage. Two cases presented preoperatively with drop of vision; one of them showed improvement and one case did not improve.
Jin et al. (2008) discussed several studies that had investigated transconjunctival access to the intraconal space; Lazar et al. (1985) used the transconjunctival approach in 11 patients with intraconal cavernous hemangioma and reported complete, uncomplicated removal of all tumors. Loewenstein et al. (1993) in a study including 33 patients with cavernous hemangioma reported the same results as Lazar. (9)
Hayyam et al. (2005) reported complete removal of intraconal cavernous hemangiomas through a transconjunctival approach in 24 cases, but in this study one of the patients lost vision due to optic nerve trauma. (10)
Xiang et al. (2008) performed transconjunctival cryo-extraction of 36 intraconal lesions; 35 of them were cavernous hemangioma and one of them was diagnosed pathologically as neurilemoma. They reported that this approach is a safe. less traumatizing and less time consuming. (11)
Renbeing et al. (2013) reported that transconjunctival approach is nearly equal to lateral orbitotomy as regard improvement of proptosis and rate of complications with less operative time. (12)
Cryo-extraction is best used in tumors and cysts containing fluid (blood or other fluid) rather than in solid tumors, because freezing occurs on the surface of the tumor as well as in the stroma and fluid or blood inside. Consequently, the outer and inner ice balls allow a strong grip to be applied by the probe, so cavernous hemangiomas are ideal for this approach. (13)
Gdal-On et al. used cryo-assisted extraction of intraconal hemangiomas and reported easy extraction in lesions touching the globe, but they did not recommend this approach in deeper lesions reaching the orbital apex, as it may endanger the apical structures. (14)
Tsirbas et al. (2005) reported that use of the cryoprobe for removal of intraconal tumors through transconjunctival approach decreased the complications of surgery. (15)
Castelnuovo et al. (2019) used the cryoprobe to extract two orbital cavernous hemangiomas transnasally and reported that the cryoprobes represent an adjunctive tool in extraction of fluid-filled intraorbital lesions.(16)
One of the limitations of this approach is the narrow working space, so the lesion’s anterior margin should be adjacent to the globe for easy, safe, handling and removal of the tumors. However, more posterior lesions will be more difficult to manipulate and will be masked by orbital fat. Use of the standard retinal cryoprobe provide a good grip to the mass even in deep lesions, without affecting the surrounding structures.
In this study we found that use of the cryoprobe for extraction of the tumors helps removal of deeper lesions that are not touching the back of the globe after exposure of a sufficient portion of the mass to provide a good grip and after retraction of the surrounding fat. Retrobulbar hemorrhage and rupture of the angioma are possible complications and should be avoided be good intraoperative hemostasis and gentle dissection of the mass respectively.