Case Reports Endoscopic Endonasal-Assisted Resection of Orbital Schwannoma Michelle T. Sun, M.B.B.S.*, Wencan Wu, M.D., Ph.D.†, Wentao Yan, B.A.†, Yunhai Tu, M.S.†, and Dinesh Selva, F.R.A.C.S., F.R.A.N.Z.C.O* Abstract: Orbital schwannomas are rare and despite a variety of external surgical approaches previously utilized, removal of tumors located in the deep orbital apex remains challenging. The endoscopic endonasal approach has been used increasingly for various apical tumours, but few describe this technique for orbital schwannomas. The authors describe 2 cases of orbital schwannoma removed via an endoscopic endonasal assisted approach. The first patient was a 31-year-old Cantonese female who was found to have an 11 × 8 × 8 mm right orbital apical schwannoma which was removed using an endoscopic endonasal sphenoethmoidal approach. The second patient was a 78-year-old Caucasian male who had a 28 × 17 × 18 mm orbital schwannoma removed via a transcaruncular and endoscopic endonasalassisted approach. These findings suggest that the use of an endonasal approach may facilitate the safe removal of selected medially located orbital schwannomas whose posterior margins involve the orbital apex.
S
chwannomas are well-differentiated solitary benign tumours arising from the schwann cells of the peripheral, cranial, sympathetic, and spinal nerves of the body.1,2 Orbital schwannomas are rare, accounting for approximately 1% to 4% of orbital tumours.1,3 A variety of external surgical approaches have been used in the treatment of orbital schwannomas.3 Despite this, the removal of tumours located in the deep orbital apex remains challenging due to the complexity of the neurovascular anatomy in this region. In recent years, there have been increasing reports of the endonasal endoscopic approach for various orbital apical tumours.4,5 However, there are only 3 cases in the literature which describe the use of this approach for orbital schwannomas, 2 of which were not completely removed.5–7 The authors present 2 cases of orbital schwannoma completely resected via endonasal endoscopic approaches, with the addition of medial rectus detachment in 1 case to facilitate access to the medial intraconal apex.
CASE REPORTS Case 1 A 31-year-old Cantonese female presented with a 2-month history of progressive blurred vision in her right eye. Her visual acuity was 6/60 in the right eye and 6/8.5 in the left eye. Examination of the right eye revealed a relative afferent pupillary defect and optic disc edema. An irregular visual field defect was noted. High-resolution CT revealed a
Accepted for publication May 29, 2015. *Discipline of Ophthalmology & Visual Sciences, The University of Adelaide and South Australian Institute of Ophthalmology, Adelaide, South Australia, Australia; and †Department of Orbital & Oculoplastic Surgery, The Eye Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, People’s Republic of China. The authors have no financial or conflicts of interest to disclose. Address correspondence and reprint requests to Michelle T. Sun, M.B.B.S., South Australian Institute of Ophthalmology, Level 8, East Wing, Royal Adelaide Hospital, Adelaide, SA 5000, Australia. E-mail:[email protected] DOI: 10.1097/IOP.0000000000000528
Ophthal Plast Reconstr Surg, Vol. XX, No. XX, 2015
contrast-enhancing right orbital apical tumor medial to the optic nerve, measuring 11 × 8 × 8 mm (Fig. 1). The tumor was surgically removed using an endoscopic endonasal sphenoethmoidal approach. Intraoperatively, the tumor was found in the deep medial intraorbital apex, adjacent to the entrance of the optic nerve into the orbit. The surgical procedure was as previously described and technique are demonstrated in Figure 2.8 Endoscopic removal of an orbital apex schwannoma first involved a standardized endoscopic transnasal ethmoidectomy, after which the lamina papyracea was removed from the periorbita until the junction between the minor wing of sphenoid bone and the optic canal was visualized (Fig. 2A). The periorbita was then incised parallel to the medial rectus muscle and removed, and some extraconal fat between the periorbita and the posterior medial rectus muscle was excised with a special suction/cutting instrument (New Direction Medical Optic Instrument Co., Ltd, Dezhou, Shandong, China) to expose the far posterior medial rectus. The medial rectus muscle tendon was then detached from the globe via a transconjunctival incision and retracted superomedially to expose the orbital apex with a blunt ribbon retractor inserted through the nose. After a little intraconal fat was suctioned with the above suction/cutting instrument (Fig. 2B), the posterior orbital apex was exposed revealing the schwannoma (Fig. 2C), which was dissected and detached from the surrounding tissues under direct visualization of the endoscope (Fig. 2D, E). The medial rectus was then reattached and the bony defect of the medial orbital wall reconstructed with a thin Medpor sheet (1 mm in thickness) by a transcaruncular approach (Fig. 2F). Pathology results revealed an orbital schwannoma and postoperative examination on the second day after surgery revealed an unchanged visual acuity of 6/60 with a right relative afferent pupillary defect and mildly dilated pupil. At the 3-week review, visual acuity improved to 6/6 without optic disc edema, which remained stable at the 6-month review, with no complications, such as dysfunction of the extraocular movements, double vision, or nasal disorders. Orbital CT scans showed no signs of recurrence or residual lesion at the orbital apex. Case 2 A 78-year-old Caucasian male underwent a routine ophthalmic examination which revealed mild to moderate optic disc edema, proptosis, and limited mobility in his left eye. His visual acuity was 6/9 bilaterally. He reported being asymptomatic and had no history of malignancy. There was no relative afferent pupillary defect. CT and MRI scans revealed a welldefined contrast-enhancing tumor at the posteromedial apical aspect of the left orbit, medial to the optic nerve measuring 28 × 17 × 18 mm (Fig. 2). Intraoperatively, the tumor was found to be in the medial orbital wall with some extension between the medial and inferior recti into the intraconal space. A left medial transcaruncular incision was made and dissection was performed to the medial orbital periosteum posterior to the posterior lacrimal crest. This was followed by dissection toward the anterior face of the tumor, which was found to be soft and encapsulated, resembling a schwannoma. The lateral aspect of the tumor was dissected back toward the apex of the tumor but the tumor mass precluded a complete view of the posterior margin of the tumor which was firmly adherent posteriorly. A standard total intranasal endoscopic spheno-ethmoidectomy was undertaken as described previously8 using a 45° endoscope (Karl Storz; Tuttlingen, Germany) to expose the posterior medial orbital wall as far as the orbital apex (Fig. 3). The lesser wing of sphenoid bone
1
Copyright © 2015 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc. Unauthorized reproduction of this article is prohibited.
Ophthal Plast Reconstr Surg, Vol. XX, No. XX, 2015
Case Reports
FIG. 1. Axial (A) and coronal (B) CT scans demonstrating an orbital apical lesion (arrow) medial to the optic nerve which was contrast enhancing on MRI (C, D) measuring approximately 11 × 0.8 mm2.
at the orbital apex was thinned using a microdrill (XPS3000, Medtronic, Minneapolis, MN, U.S.A.). The medial orbital wall was dissected off the perorbita and removed with a microcurette/freer elevator, as far posteriorly as the junction between the lesser wing of the sphenoid bone and the optic canal, anteriorly to a point 1 cm behind the maxillary line equivalent to the anterior extent of the tumor. Bone was also removed superiorly to the ethmoid roof and inferiorly to the inferomedial strut between the maxillary sinus and the ethmoid sinus. The periorbita was opened with a sickle knife to expose the tumor. The tumor was visualized extending into the apex of the orbit and the posterior margin was dissected free from the orbital apex using a pediatric ball probe and microdissectors. This was facilitated by lateral retraction of the anterior tumor using a malleable retractor via the transcaruncular incision. Prolapse of the tumor into the sinuses also enabled further dissection along the lateral margin via the transcaruncular approach. The posterior apex of the tumor was then delivered into the nasal cavity and the tumor was extracted via the nose. The medial wall was not reconstructed as it was felt the risk of symptomatic enophthalmos (>2 mm) was not significant and the patient had not been concerned with the possibility in preoperative discussions. Pathology results revealed an orbital schwannoma. Postoperative review at 4 weeks revealed unchanged visual acuity with mild diplopia on downgaze. There was improvement of the optic disc edema. At 12-month follow up, he had 2 mm of enophthalmos and no diplopia with full extraocular movements.
DISCUSSION The surgical approach to the orbital apex remains challenging due to the anatomic constraints in this area. Traditional surgical techniques for access to lesions in this area include medial and lateral orbitotomies and transcranial approaches.9 In recent years, the endoscopic approach has been utilized increasing for the management of orbital apical lesions.5,6,8,10 The endoscopic approach may, in selected cases, facilitate superior
2
FIG. 2. The technique for endoscopic removal of an orbital apex schwannoma involves removal of the lamina papracea exposing the junction between the minor wing of sphenoid bone and optic canal (A). Thereafter, the posterior orbital apex can be exposed (B) revealing the schwannoma (C), which is dissected and detached from surrounding tissue (D, E). The defect is then repaired with a thin Medpor sheet via a transcuruncular approach (F).
© 2015 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.
Copyright © 2015 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc. Unauthorized reproduction of this article is prohibited.
Ophthal Plast Reconstr Surg, Vol. XX, No. XX, 2015
Case Reports
FIG. 3. Axial (A) and coronal (B) T1-weighted fat suppressed MRI images demonstrating a moderately enhancing extraconal mass measuring 28 × 17 × 18 mm and displacing the medial rectus muscle and optic nerve laterally. Intraoperatively, an endoscopic view demonstrates blunt dissection of the posterior margin of the schwannoma (C, arrow) using a ball probe. A malleable retractor, inserted through the transcaruncular incision, is retracting the schwannoma laterally.
visualization and improved exposure when compared with more traditional techniques. However, to date there have been only 3 previous reports in the literature of orbital schwannomas removed, or partially removed with the use of an endoscopic approach.5,6 The authors add a further 2 cases of orbital schwannoma removed using an endoscopic endonasal technique, which involved medial rectus muscle detachment via a transconjuctival incision in 1 case, and combined with a transcaruncular approach the second case. Initially described in 1990 for the treatment of dysthyroid orbitopathy,11 the endoscopic endonasal approach to the orbit was first used in the management of orbital apical tumours by Sethi and Lau.8 Since then, additional techniques allowing for complete resections of both intra- and extraconal orbital apical tumours have been described for cavernous haemangiomas and solitary fibrous tumours.4,12,13 The anatomical complexities of the orbital apex complicates removal of lesions from this region due to the many delicate structures within the vicinity. Dallan et al.14 recently characterized the orbital apex from an endonasal perspective, describing the exposure of the orbital apex when the connective tissue at the level of the medial aspect of the superior orbital fissure was dissected, and thereafter entering the posterior orbit after division of the medial and inferior rectus revealing the location of 2 main branches of the oculomotor nerve, and the first segment of the ophthalmic artery. In 2009, Murchison et al.6 described a series of 3 extraconal orbital apex tumours, including 1 schwannoma, which were biopsied and debulked prior to excision via an endoscopic endonasal technique. Murchison et al.6 described the addition of a nasal septectomy to improve visualization and access to the orbital apex in all 3 cases without any postoperative complications. Subsequently, Lee et al.5 described a series of 5 cases of orbital apex tumours removed using an endoscopic technique, including 1 case of an orbital schwannoma removed with the addition of a medial transconjunctival approach to facilitate protection of the orbital contents. Recently, Castelnuovo et al.7 described a series of 16 intraobital medially located cases removed via an endoscopic approach. Among these, 1 was an orbital schwannoma, although only partial resection was possible. In the first case, the orbital schwannoma was removed using an endoscopic endonasal sphenoethmoidal approach, combined with medial rectus muscle detachment via a transconjunctival approach.10 In the authors’ experience, the
endonasal approach can lead to superior visualization with improved exposure, and reduced neurovascular retraction when compared with a purely transcaruncular approach in selected cases of medial apical tumors. The transethmoidal approach also represents a less invasive procedure in comparison with the option of a transcranial approach for tumors in this location. As the authors have described previously, detachment of the medial rectus facilitates retraction of the muscle and a better exposure of the medial intraconal apex.10 In neither of the cases was septectomy found to be necessary for adequate visualization or access. In the second case, an endoscopic approach was added primarily to enable dissection of the posterior margin of the tumor under direct visualization and magnification. The ethmoidectomy and medial wall decompression also provided space for the tumor to be moved medially, facilitating the dissection along the lateral aspect. It is recognized that this can also be achieved via a transcaruncular approach by infracturing the medial wall and/or performing a lateral orbitotomy to abduct the lateral wall and globe to provide more room for dissection. However, the preference was to perform an endonasal ethmoidectomy to provide direct visualization of the dissection of the posterior margin which was densely adherent at the apex. Removal via an external approach alone would have necessitated significant blind traction or dissection to free the posterior aspect of the tumor. The addition of the endonasal approach also served to decrease traction on orbital contents as well as minimizing the chances of sinus dysfunction that might occur with simple medial wall infracture. The authors did not experience any difficulties with bleeding in either case described. Bleeding, if encountered, is managed with standard techniques including use of neuropatties, endonasal suction, bipolar cautery, or standard bipolar cautery via the external excision as necessary. In summary, the authors believe the use of an endonasal approach may facilitate the safe removal of selected medially located orbital schwannomas whose posterior margins involve the orbital apex.
REFERENCES 1. Rootman J, Goldberg C, Robertson W. Primary orbital schwannomas. Br J Ophthalmol 1982;66:194–204. 2. Kashyap S, Pushker N, Meel R, et al. Orbital schwannoma with cystic degeneration. Clin Exp Ophthalmol 2009;37:293–8.
© 2015 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.
3
Copyright © 2015 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc. Unauthorized reproduction of this article is prohibited.
Ophthal Plast Reconstr Surg, Vol. XX, No. XX, 2015
Case Reports
3. Schick U, Bleyen J, Hassler W. Treatment of orbital schwannomas and neurofibromas. Br J Neurosurg 2003;17:541–5. 4. Herman P, Lot G, Silhouette B, et al. Transnasal endoscopic removal of an orbital cavernoma. Ann Otol Rhinol Laryngol 1999;108:147–50. 5. Lee JY, Ramakrishnan VR, Chiu AG, et al. Endoscopic endonasal surgical resection of tumors of the medial orbital apex and wall. Clin Neurol Neurosurg 2012;114:93–8. 6. Murchison AP, Rosen MR, Evans JJ, et al. Posterior nasal septectomy in endoscopic orbital apex surgery. Ophthal Plast Reconstr Surg 2009;25:458–63. 7. Castelnuovo P, Dallan I, Locatelli D, et al. Endoscopic transnasal intraorbital surgery: our experience with 16 cases. Eur Arch Otorhinolaryngol 2012;269:1929–35. 8. Sethi DS, Lau DP. Endoscopic management of orbital apex lesions. Am J Rhinol 1997;11:449–55. 9. Leone CR, Jr, Wissinger JP. Surgical approaches to diseases of the orbital apex. Ophthalmology 1988;95:391–7.
4
10. Wu W, Selva D, Jiang F, et al. Endoscopic transethmoidal approach with or without medial rectus detachment for orbital apical cavernous hemangiomas. Am J Ophthalmol 2013;156:593–99. 11. Kennedy DW, Goodstein ML, Miller NR, et al. Endoscopic transnasal orbital decompression. Arch Otolaryngol Head Neck Surg 1990;116:275–82. 12. Karaki M, Kobayashi R, Mori N. Removal of an orbital apex hemangioma using an endoscopic transethmoidal approach: technical note. Neurosurgery 2006;59(1 Suppl 1):ONSE159–60; discussion ONSE159–60. 13. Miller NR, Agrawal N, Sciubba JJ, et al. Image-guided transnasal endoscopic resection of an orbital solitary fibrous tumor. Ophthal Plast Reconstr Surg 2008;24:65–7. 14. Dallan I, Castelnuovo P, de Notaris M, et al. Endoscopic endonasal anatomy of superior orbital fissure and orbital apex regions: critical considerations for clinical applications. Eur Arch Otorhinolaryngol 2013;270:1643–9.
© 2015 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.
Copyright © 2015 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc. Unauthorized reproduction of this article is prohibited.
S
chwannomas are well-differentiated solitary benign tumours arising from the schwann cells of the peripheral, cranial, sympathetic, and spinal nerves of the body.1,2 Orbital schwannomas are rare, accounting for approximately 1% to 4% of orbital tumours.1,3 A variety of external surgical approaches have been used in the treatment of orbital schwannomas.3 Despite this, the removal of tumours located in the deep orbital apex remains challenging due to the complexity of the neurovascular anatomy in this region. In recent years, there have been increasing reports of the endonasal endoscopic approach for various orbital apical tumours.4,5 However, there are only 3 cases in the literature which describe the use of this approach for orbital schwannomas, 2 of which were not completely removed.5–7 The authors present 2 cases of orbital schwannoma completely resected via endonasal endoscopic approaches, with the addition of medial rectus detachment in 1 case to facilitate access to the medial intraconal apex.
CASE REPORTS Case 1 A 31-year-old Cantonese female presented with a 2-month history of progressive blurred vision in her right eye. Her visual acuity was 6/60 in the right eye and 6/8.5 in the left eye. Examination of the right eye revealed a relative afferent pupillary defect and optic disc edema. An irregular visual field defect was noted. High-resolution CT revealed a
Accepted for publication May 29, 2015. *Discipline of Ophthalmology & Visual Sciences, The University of Adelaide and South Australian Institute of Ophthalmology, Adelaide, South Australia, Australia; and †Department of Orbital & Oculoplastic Surgery, The Eye Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, People’s Republic of China. The authors have no financial or conflicts of interest to disclose. Address correspondence and reprint requests to Michelle T. Sun, M.B.B.S., South Australian Institute of Ophthalmology, Level 8, East Wing, Royal Adelaide Hospital, Adelaide, SA 5000, Australia. E-mail:[email protected] DOI: 10.1097/IOP.0000000000000528
Ophthal Plast Reconstr Surg, Vol. XX, No. XX, 2015
contrast-enhancing right orbital apical tumor medial to the optic nerve, measuring 11 × 8 × 8 mm (Fig. 1). The tumor was surgically removed using an endoscopic endonasal sphenoethmoidal approach. Intraoperatively, the tumor was found in the deep medial intraorbital apex, adjacent to the entrance of the optic nerve into the orbit. The surgical procedure was as previously described and technique are demonstrated in Figure 2.8 Endoscopic removal of an orbital apex schwannoma first involved a standardized endoscopic transnasal ethmoidectomy, after which the lamina papyracea was removed from the periorbita until the junction between the minor wing of sphenoid bone and the optic canal was visualized (Fig. 2A). The periorbita was then incised parallel to the medial rectus muscle and removed, and some extraconal fat between the periorbita and the posterior medial rectus muscle was excised with a special suction/cutting instrument (New Direction Medical Optic Instrument Co., Ltd, Dezhou, Shandong, China) to expose the far posterior medial rectus. The medial rectus muscle tendon was then detached from the globe via a transconjunctival incision and retracted superomedially to expose the orbital apex with a blunt ribbon retractor inserted through the nose. After a little intraconal fat was suctioned with the above suction/cutting instrument (Fig. 2B), the posterior orbital apex was exposed revealing the schwannoma (Fig. 2C), which was dissected and detached from the surrounding tissues under direct visualization of the endoscope (Fig. 2D, E). The medial rectus was then reattached and the bony defect of the medial orbital wall reconstructed with a thin Medpor sheet (1 mm in thickness) by a transcaruncular approach (Fig. 2F). Pathology results revealed an orbital schwannoma and postoperative examination on the second day after surgery revealed an unchanged visual acuity of 6/60 with a right relative afferent pupillary defect and mildly dilated pupil. At the 3-week review, visual acuity improved to 6/6 without optic disc edema, which remained stable at the 6-month review, with no complications, such as dysfunction of the extraocular movements, double vision, or nasal disorders. Orbital CT scans showed no signs of recurrence or residual lesion at the orbital apex. Case 2 A 78-year-old Caucasian male underwent a routine ophthalmic examination which revealed mild to moderate optic disc edema, proptosis, and limited mobility in his left eye. His visual acuity was 6/9 bilaterally. He reported being asymptomatic and had no history of malignancy. There was no relative afferent pupillary defect. CT and MRI scans revealed a welldefined contrast-enhancing tumor at the posteromedial apical aspect of the left orbit, medial to the optic nerve measuring 28 × 17 × 18 mm (Fig. 2). Intraoperatively, the tumor was found to be in the medial orbital wall with some extension between the medial and inferior recti into the intraconal space. A left medial transcaruncular incision was made and dissection was performed to the medial orbital periosteum posterior to the posterior lacrimal crest. This was followed by dissection toward the anterior face of the tumor, which was found to be soft and encapsulated, resembling a schwannoma. The lateral aspect of the tumor was dissected back toward the apex of the tumor but the tumor mass precluded a complete view of the posterior margin of the tumor which was firmly adherent posteriorly. A standard total intranasal endoscopic spheno-ethmoidectomy was undertaken as described previously8 using a 45° endoscope (Karl Storz; Tuttlingen, Germany) to expose the posterior medial orbital wall as far as the orbital apex (Fig. 3). The lesser wing of sphenoid bone
1
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Ophthal Plast Reconstr Surg, Vol. XX, No. XX, 2015
Case Reports
FIG. 1. Axial (A) and coronal (B) CT scans demonstrating an orbital apical lesion (arrow) medial to the optic nerve which was contrast enhancing on MRI (C, D) measuring approximately 11 × 0.8 mm2.
at the orbital apex was thinned using a microdrill (XPS3000, Medtronic, Minneapolis, MN, U.S.A.). The medial orbital wall was dissected off the perorbita and removed with a microcurette/freer elevator, as far posteriorly as the junction between the lesser wing of the sphenoid bone and the optic canal, anteriorly to a point 1 cm behind the maxillary line equivalent to the anterior extent of the tumor. Bone was also removed superiorly to the ethmoid roof and inferiorly to the inferomedial strut between the maxillary sinus and the ethmoid sinus. The periorbita was opened with a sickle knife to expose the tumor. The tumor was visualized extending into the apex of the orbit and the posterior margin was dissected free from the orbital apex using a pediatric ball probe and microdissectors. This was facilitated by lateral retraction of the anterior tumor using a malleable retractor via the transcaruncular incision. Prolapse of the tumor into the sinuses also enabled further dissection along the lateral margin via the transcaruncular approach. The posterior apex of the tumor was then delivered into the nasal cavity and the tumor was extracted via the nose. The medial wall was not reconstructed as it was felt the risk of symptomatic enophthalmos (>2 mm) was not significant and the patient had not been concerned with the possibility in preoperative discussions. Pathology results revealed an orbital schwannoma. Postoperative review at 4 weeks revealed unchanged visual acuity with mild diplopia on downgaze. There was improvement of the optic disc edema. At 12-month follow up, he had 2 mm of enophthalmos and no diplopia with full extraocular movements.
DISCUSSION The surgical approach to the orbital apex remains challenging due to the anatomic constraints in this area. Traditional surgical techniques for access to lesions in this area include medial and lateral orbitotomies and transcranial approaches.9 In recent years, the endoscopic approach has been utilized increasing for the management of orbital apical lesions.5,6,8,10 The endoscopic approach may, in selected cases, facilitate superior
2
FIG. 2. The technique for endoscopic removal of an orbital apex schwannoma involves removal of the lamina papracea exposing the junction between the minor wing of sphenoid bone and optic canal (A). Thereafter, the posterior orbital apex can be exposed (B) revealing the schwannoma (C), which is dissected and detached from surrounding tissue (D, E). The defect is then repaired with a thin Medpor sheet via a transcuruncular approach (F).
© 2015 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.
Copyright © 2015 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc. Unauthorized reproduction of this article is prohibited.
Ophthal Plast Reconstr Surg, Vol. XX, No. XX, 2015
Case Reports
FIG. 3. Axial (A) and coronal (B) T1-weighted fat suppressed MRI images demonstrating a moderately enhancing extraconal mass measuring 28 × 17 × 18 mm and displacing the medial rectus muscle and optic nerve laterally. Intraoperatively, an endoscopic view demonstrates blunt dissection of the posterior margin of the schwannoma (C, arrow) using a ball probe. A malleable retractor, inserted through the transcaruncular incision, is retracting the schwannoma laterally.
visualization and improved exposure when compared with more traditional techniques. However, to date there have been only 3 previous reports in the literature of orbital schwannomas removed, or partially removed with the use of an endoscopic approach.5,6 The authors add a further 2 cases of orbital schwannoma removed using an endoscopic endonasal technique, which involved medial rectus muscle detachment via a transconjuctival incision in 1 case, and combined with a transcaruncular approach the second case. Initially described in 1990 for the treatment of dysthyroid orbitopathy,11 the endoscopic endonasal approach to the orbit was first used in the management of orbital apical tumours by Sethi and Lau.8 Since then, additional techniques allowing for complete resections of both intra- and extraconal orbital apical tumours have been described for cavernous haemangiomas and solitary fibrous tumours.4,12,13 The anatomical complexities of the orbital apex complicates removal of lesions from this region due to the many delicate structures within the vicinity. Dallan et al.14 recently characterized the orbital apex from an endonasal perspective, describing the exposure of the orbital apex when the connective tissue at the level of the medial aspect of the superior orbital fissure was dissected, and thereafter entering the posterior orbit after division of the medial and inferior rectus revealing the location of 2 main branches of the oculomotor nerve, and the first segment of the ophthalmic artery. In 2009, Murchison et al.6 described a series of 3 extraconal orbital apex tumours, including 1 schwannoma, which were biopsied and debulked prior to excision via an endoscopic endonasal technique. Murchison et al.6 described the addition of a nasal septectomy to improve visualization and access to the orbital apex in all 3 cases without any postoperative complications. Subsequently, Lee et al.5 described a series of 5 cases of orbital apex tumours removed using an endoscopic technique, including 1 case of an orbital schwannoma removed with the addition of a medial transconjunctival approach to facilitate protection of the orbital contents. Recently, Castelnuovo et al.7 described a series of 16 intraobital medially located cases removed via an endoscopic approach. Among these, 1 was an orbital schwannoma, although only partial resection was possible. In the first case, the orbital schwannoma was removed using an endoscopic endonasal sphenoethmoidal approach, combined with medial rectus muscle detachment via a transconjunctival approach.10 In the authors’ experience, the
endonasal approach can lead to superior visualization with improved exposure, and reduced neurovascular retraction when compared with a purely transcaruncular approach in selected cases of medial apical tumors. The transethmoidal approach also represents a less invasive procedure in comparison with the option of a transcranial approach for tumors in this location. As the authors have described previously, detachment of the medial rectus facilitates retraction of the muscle and a better exposure of the medial intraconal apex.10 In neither of the cases was septectomy found to be necessary for adequate visualization or access. In the second case, an endoscopic approach was added primarily to enable dissection of the posterior margin of the tumor under direct visualization and magnification. The ethmoidectomy and medial wall decompression also provided space for the tumor to be moved medially, facilitating the dissection along the lateral aspect. It is recognized that this can also be achieved via a transcaruncular approach by infracturing the medial wall and/or performing a lateral orbitotomy to abduct the lateral wall and globe to provide more room for dissection. However, the preference was to perform an endonasal ethmoidectomy to provide direct visualization of the dissection of the posterior margin which was densely adherent at the apex. Removal via an external approach alone would have necessitated significant blind traction or dissection to free the posterior aspect of the tumor. The addition of the endonasal approach also served to decrease traction on orbital contents as well as minimizing the chances of sinus dysfunction that might occur with simple medial wall infracture. The authors did not experience any difficulties with bleeding in either case described. Bleeding, if encountered, is managed with standard techniques including use of neuropatties, endonasal suction, bipolar cautery, or standard bipolar cautery via the external excision as necessary. In summary, the authors believe the use of an endonasal approach may facilitate the safe removal of selected medially located orbital schwannomas whose posterior margins involve the orbital apex.
REFERENCES 1. Rootman J, Goldberg C, Robertson W. Primary orbital schwannomas. Br J Ophthalmol 1982;66:194–204. 2. Kashyap S, Pushker N, Meel R, et al. Orbital schwannoma with cystic degeneration. Clin Exp Ophthalmol 2009;37:293–8.
© 2015 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.
3
Copyright © 2015 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc. Unauthorized reproduction of this article is prohibited.
Ophthal Plast Reconstr Surg, Vol. XX, No. XX, 2015
Case Reports
3. Schick U, Bleyen J, Hassler W. Treatment of orbital schwannomas and neurofibromas. Br J Neurosurg 2003;17:541–5. 4. Herman P, Lot G, Silhouette B, et al. Transnasal endoscopic removal of an orbital cavernoma. Ann Otol Rhinol Laryngol 1999;108:147–50. 5. Lee JY, Ramakrishnan VR, Chiu AG, et al. Endoscopic endonasal surgical resection of tumors of the medial orbital apex and wall. Clin Neurol Neurosurg 2012;114:93–8. 6. Murchison AP, Rosen MR, Evans JJ, et al. Posterior nasal septectomy in endoscopic orbital apex surgery. Ophthal Plast Reconstr Surg 2009;25:458–63. 7. Castelnuovo P, Dallan I, Locatelli D, et al. Endoscopic transnasal intraorbital surgery: our experience with 16 cases. Eur Arch Otorhinolaryngol 2012;269:1929–35. 8. Sethi DS, Lau DP. Endoscopic management of orbital apex lesions. Am J Rhinol 1997;11:449–55. 9. Leone CR, Jr, Wissinger JP. Surgical approaches to diseases of the orbital apex. Ophthalmology 1988;95:391–7.
4
10. Wu W, Selva D, Jiang F, et al. Endoscopic transethmoidal approach with or without medial rectus detachment for orbital apical cavernous hemangiomas. Am J Ophthalmol 2013;156:593–99. 11. Kennedy DW, Goodstein ML, Miller NR, et al. Endoscopic transnasal orbital decompression. Arch Otolaryngol Head Neck Surg 1990;116:275–82. 12. Karaki M, Kobayashi R, Mori N. Removal of an orbital apex hemangioma using an endoscopic transethmoidal approach: technical note. Neurosurgery 2006;59(1 Suppl 1):ONSE159–60; discussion ONSE159–60. 13. Miller NR, Agrawal N, Sciubba JJ, et al. Image-guided transnasal endoscopic resection of an orbital solitary fibrous tumor. Ophthal Plast Reconstr Surg 2008;24:65–7. 14. Dallan I, Castelnuovo P, de Notaris M, et al. Endoscopic endonasal anatomy of superior orbital fissure and orbital apex regions: critical considerations for clinical applications. Eur Arch Otorhinolaryngol 2013;270:1643–9.
© 2015 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.
Copyright © 2015 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc. Unauthorized reproduction of this article is prohibited.
