Acta Neurochir (2014) 156:1891–1896 DOI 10.1007/s00701-014-2199-1
HOW I DO IT - NEUROSURGICAL TECHNIQUES
How I do it: the endoscopic endonasal optic nerve and orbital apex decompression Timothée Jacquesson & Lucie Abouaf & Moncef Berhouma & Emmanuel Jouanneau
Received: 15 May 2014 / Accepted: 25 July 2014 / Published online: 22 August 2014 # Springer-Verlag Wien 2014
ABSTRACT Background With the refinement of the technique, endoscopic endonasal surgery increases its field of indications. The orbital compartment is among the locations easily reached through the nostril. This anteromedial approach has been described primarily for inflammatory or traumatic diseases, with few data for tumoral diseases. Method Since 2010, this route has been used at our institution either for decompression or for biopsy of orbital tumoral diseases. Findings/Conclusions Even if further studies are warranted, this strategy proved to be beneficial for patients, with improvements in visual outcome. In this article, the authors summarize their technique and their experience with endonasal endoscopic orbital decompression. Electronic supplementary material The online version of this article (doi:10.1007/s00701-014-2199-1) contains supplementary material, which is available to authorized users. T. Jacquesson : M. Berhouma : E. Jouanneau Skull Base Surgery Unit – Department of Neurosurgery B, Pierre Wertheimer Neurological and Neurosurgical Hospital – Hospices Civils de Lyon, Lyon, France T. Jacquesson : E. Jouanneau Research and Education Unit of Medicine, Claude Bernard University Lyon 1, Lyon, France L. Abouaf Department of Neuro-ophthalmology (Pr A Vighetto), Pierre Wertheimer Neurological and Neurosurgical Hospital – Hospices Civils de Lyon, Lyon, France
Key points • Nasal and sphenoidal anatomies determine the feasibility and risks for doing an efficient medial optic or orbit decompression. • Techniques and tools used are those developed for pituitary surgery. • A middle turbinectomy and posterior ethmoidectomy are mandatory to expose the medial wall of the orbit. • The Onodi cell is a key marker for the optic canal and must be opened up with caution. • The lamina papyracea is opened first with a spatula and the optic canal opened up by a gentle drilling under continuous irrigation from distal to proximal. • Drilling might always be used under continuous irrigation to avoid overheating of the optic nerve. An ultrasonic device can be used as well. • The nasal corridor is narrow and instruments may hide the infrared neuronavigation probe. To overcome this issue, a magnetic device could be useful. • Doppler control could be useful to locate the ICA. • The optic canal must be opened up from the tuberculum of the sella to the orbital apex and from the planum (anterior cranial fossa) to the lateral OCR or ICA canal • At the end of the procedure, the optic nerve becomes frequently pulsatile, which is a good marker of decompression. Keywords Skull base surgery . Minimally invasive neurosurgery . Endoscopic endonasal surgery . Optic nerve tumors . Orbital Tumors . Trans-sphenoidal approach
E. Jouanneau INSERM U1028, CNRS UMR5292, Neurosciences Research Center of Lyon, Neuro-oncology and Neuro-inflammation team, Lyon, France
Introduction
T. Jacquesson (*) Skull Base Surgery Unit – Department of Neurosurgery A, Pierre Wertheimer Neurological and Neurosurgical Hospital – Hospices Civils de Lyon, 59 Boulevard Pinel, 69394 Lyon, Cedex 03, France e-mail: [email protected]
With the development of the technique, endoscopic endonasal surgery increases its field of application both for treating diseases and accessing challenging anatomical locations [1]. Routinely used for pituitary surgery, the endoscopic naso-
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Acta Neurochir (2014) 156:1891–1896
Fig. 1 a: Anatomical view view of the sphenoid sinus. DM: duramater of the sella turcica; OP: optic Prominence; CP: carotid prominence; OCR: Lateral Optico Carotid Recess; PS: Planum Sphenoidal. b: anatomical data after large opening of the sphenoid and ethmoidal sinuses. ON: Optic Nerve; C5 ICA: C5 portion of the Internal Carotid; ST: Sella Turcica
sphenoidal route provides minimally-invasive access to the medial compartment of the orbit and the optic nerve. This has been underused for tumoral diseases [10, 9]. Thus, a visual impairment can result from compression due to inextensible bony walls. The extradural approach with the aperture of the optic canal, anterior clinoidectomy, or lateral orbitotomy is routinely performed for decompression, with some morbidity [7] and the medial nasal approach represents another option. This route can also be used for tumor biopsy or removal, although inadequate instrumentation still prevents expansion of indications [3]. We describe the tips and tricks for optic and orbital endoscopic endonasal decompression.
Nasal phase A uninostril approach, on the same side of the optic nerve or orbit we want to reach, is used. A 0° short rigid endoscope (18 cm length, 4 mm diameter, Storz®, Tuttlingen, Germany) is introduced inside the nostril and a middle turbinectomy is first done followed by a posterior ethmoidectomy (Fig. 2 a and b). Sphenoidal phase The mucosa is coagulated medially to the sphenoid ostium and the posterior bony septum is pushed away until the contralateral ostium can be seen. The vomer is then removed using a bone forceps, and the sphenoidotomy is enlarged laterally to expose the optic nerve and ICA (Fig. 1a).
Relevant surgical anatomy Orbital apex and optic canal opening Lateral to the sella turcica is the optic canal (OC) with the C5 paraclinoid portion of the Internal Carotid Artery (ICA) (Fig. 1a). The medial and lateral optico-carotid recesses respectively correspond to the middle and the anterior clinoid processes. The OC is in close contact with the Onodi Cell (the most posterior ethmoidal cell) (Fig. 2 a and b). The orbital apex prolongs anteriorly along the OC and lies above the superior orbital fissure (Fig. 1b). The orbit is limited medially by the laminae papyracea (cells of the lateral massa of the ethmoid) (Fig. 2a) and inferiorly by the maxillary sinus.
When starting to work around the optic nerve, a long endoscope (30 cm) is positioned in the upper part of the nostril and secured in the holder. The surgical tools can be passed below the endoscope. The thin lamina papyracea is first opened up with a spatula. The opening of the OC is done from distal to proximal to the tuberculum of the sella by a gentle drilling, and the bone pellicle is finally removed with a spatula or with a bone punch. The OC aperture must be as large as possible, especially at the superior and inferior parts of the OC until the planum and the OCR, respectively. A clockwise 180° of freedom of the optic nerve may be expected (Fig. 3 a and b). The medial orbital decompression can be extended as anteriorly as needed according to the tumor anatomy (Fig. 4).
Description of the technique
Closure and postoperative care
Positioning and anesthesia
Sinuses and the nostril are cleaned with saline solution and the hemostasis checked. No nasal packing is needed. Postoperatively, no intensive care is needed. Vision and nasal flow are regularly checked for the first few days. A CT
The patient’s positioning and pre-operative steps are similar to regular pituitary cases and have been previously described [2].
Acta Neurochir (2014) 156:1891–1896
1893
Fig. 2 a: cranio-facial axial CT showing the thin lamea papyracea, the medial wall of the orbit, and the OC (Onodi Cell) posterior ethmoidal cell in direct contact with the ON (Optic Nerve). b: Cranio-facial coronal CT showing the OC and the ON
scan is done on day one and the patient is discharged from the hospital at day three. An endoscopic nasal check-up is done within three weeks after the surgery. Visual and MRI evaluation is planned at three months and thereafter, depending on the underlying disease.
Indications (Fig. 4) Inflammatory (Grave’s orbitopathy) or traumatic diseases represent traditional indications of endonasal orbital decompression [5, 8]. Fig. 3 a: Operative view of the sphenoid sinus with the ON (Optic Nerve), the Orbital apex, the C5 ICA (C5 portion of the ICA), the TS (tuberculum of the Sella) and the planum. b: Operative view after the optic nerve and the orbital apex decompression. The DM (DuraMater) of the planum and the TS (Tuberculum of the Sella) have been exposed to ensure a complete optic decompression
This may also be discussed in the case of tumors of the optic nerve or orbital apex, mainly for meningiomas when a visual impairment occurs (Fig. 5). For spheno-orbital meningiomas, this approach can be used first to decompress the optic nerve before doing the regular lateral orbitotomy. Indeed, in many cases, the hyperostosis stays lateral, and this may reduce optic nerve suffering during the second procedure. This approach can also be used to realize tumor biopsies or removal when the tumors are located medially into the orbit.
1894
Acta Neurochir (2014) 156:1891–1896
Fig. 4 Examples of tumors that may benefit from an endonasal endoscopic surgery. a: Optic nerve sheath meningioma. b: Optic nerve sheath meningioma. c: Spheno-orbital meningioma
Limitations Complex sphenoid septa and/or weak pneumatization can lead to exposure difficulties with time-consuming and risky drilling [4]. The same difficulties can be encountered in cases of medial hyperostosis. As soon as the periorbita is opened up, the orbital fat and muscles get out. Thus, orbital tumors may be hard to identify and remove, as retractors for orbital content are still missing.
– –
The surgeon may be aware that the ophthalmic artery can emerge from the medial or inferior part of the optic canal in cases of biopsy or removal [6]. Dura mater of the anterior skull base is fragile in this location and must be pushed away when drilling to avoid a CSF leak.
Specific perioperative considerations How to avoid complications –
– – –
Pre-operative assessment of imaging exams (CT-scan and MRI, angioMRI) must study the anatomy to anticipate surgical difficulties (megaturbinates, septal deviation, sphenoid pneumatization and septas, length of the OC, hyperostosis, ICA positioning). Careful opening of the Onodi cell is mandatory to avoid ON injury. Keeping the bone of the C5 ICA canal intact is useful to decrease the vascular risk when opening the inferior part of the optic canal. Posterior ethmoidal arteries must be identified.
Preoperatively, a cranio-facial CT and MRI are done and used for neuronavigation during the surgery. Mandatorily, a visual assessment includes bilateral visual acuity, fundoscopy, and computerized visual field. A rigorous preoperative preparation is systematic, including nasal rinsing and iodine ointment the day before and just before surgery. Postoperatively, no intensive care is needed. Vision as well as nasal flow are checked every two hours the first night and twice daily thereafter. A Ct scan is done at day one and the patient is dischargesd from the hospital at day two or three. An endoscopic nasal check-up is done within two or three weeks after the surgery to control mucosae and sinus
Acta Neurochir (2014) 156:1891–1896
1895
Fig. 5 a and b: Ophthalmologic results before (up) and after (down) an endonsasal endoscopic optic nerve and orbital apex decompression for a sphenoorbital meningioma (decompression between the two arrows). Both the visual acuity and field have been improved
healing. Postoperative visual and MRI evaluation is planned at three months and thereafter depending on the underlying disease.
available instrumentation, particularly orbital fat retractors and angled instruments.
Specific information to give to the patient
Conflict of interest None.
Patients have to be aware of potential visual and vascular risks. As for pituitary surgery, the postoperative rhinological discomfort and CSF leak rate are very minimal. Finally, the patient must be aware that coughing, sneezing, or blowing the nose may result in exophthalmia because of air getting into the orbit and, therefore, should be avoided during the first days.
References
Conclusion The nasal route is a smart one for reaching the optic or orbital compartments for various diseases but is still underused for tumoral ones. This may represent an easy way to decompress the optic canal or orbital apex in case of medial tiny bone but needs specific training and materials. Further evaluations of functional results are required. Tumor biopsies can also be done but tumor removal still requires a refinement of the
1. Berhouma M, Messerer M, Jouanneau E (2012) Shifting paradigm in skull base surgery: Roots, current state of the art and future trends of endonasal endoscopic approaches. Rev Neurol (Paris) 168(2):121– 134 2. Berhouma M, Messerer M, Jouanneau E (2012) Occam’s razor in minimally invasive pituitary surgery: tailoring the endoscopic endonasal uninostril trans-sphenoidal approach to sella turcica. Acta Neurochir (Wien). doi:10.1007/s00701-012-1510-2 3. Cebula H, Lahlou A, De Battista JC, Debry C, Froelich S (2010) Endoscopic approaches to the orbit. Neurochirurgie 56(2–3):230– 235 4. Hart CK, Theodosopoulos PV, Zimmer LA (2009) Anatomy of the optic canal: a computed tomography study of endoscopic nerve decompression. Ann Otol Rhinol Laryngol 118(12):839–844 5. Jiang RS, Hsu CY, Shen BH (2001) Endoscopic optic nerve decompression for the treatment of traumatic optic neuropathy. Rhinology 39(2):71–74
1896 6. Locatelli M, Caroli M, Pluderi M, Motta F, Gaini SM, Tschabitscher M, Scarone P (2011) Endoscopic transsphenoidal optic nerve decompression: an anatomical study. Surg Radiol Anat 33(3):257–262 7. Mariniello G, Bonavolontà G, Tranfa F, Maiuri F (2013) Management of the optic canal invasion and visual outcome in spheno-orbital meningiomas. Clin Neurol Neurosurg 115(9):1615–1620 8. Michel O, Oberländer N, Neugebauer P, Neugebauer A, Rüssmann W (2001) Follow-up of transnasal orbital
Acta Neurochir (2014) 156:1891–1896 decompression in severe Graves’ ophthalmopathy. Ophthalmology 108(2):400–404 9. Netuka D, Masopust V, Belšán T, Profantová N, Beneš V (2013) Endoscopic endonasal resection of medial orbital lesions with intraoperative MRI. Acta Neurochir (Wien) 155(3):455–461 10. Sia DIT, Chan WO, Wormald PJ, Davis G, Selva D (2012) Decompression of benign orbital apex lesion via medial endoscopic approach. Orbit 31(5):344–346
HOW I DO IT - NEUROSURGICAL TECHNIQUES
How I do it: the endoscopic endonasal optic nerve and orbital apex decompression Timothée Jacquesson & Lucie Abouaf & Moncef Berhouma & Emmanuel Jouanneau
Received: 15 May 2014 / Accepted: 25 July 2014 / Published online: 22 August 2014 # Springer-Verlag Wien 2014
ABSTRACT Background With the refinement of the technique, endoscopic endonasal surgery increases its field of indications. The orbital compartment is among the locations easily reached through the nostril. This anteromedial approach has been described primarily for inflammatory or traumatic diseases, with few data for tumoral diseases. Method Since 2010, this route has been used at our institution either for decompression or for biopsy of orbital tumoral diseases. Findings/Conclusions Even if further studies are warranted, this strategy proved to be beneficial for patients, with improvements in visual outcome. In this article, the authors summarize their technique and their experience with endonasal endoscopic orbital decompression. Electronic supplementary material The online version of this article (doi:10.1007/s00701-014-2199-1) contains supplementary material, which is available to authorized users. T. Jacquesson : M. Berhouma : E. Jouanneau Skull Base Surgery Unit – Department of Neurosurgery B, Pierre Wertheimer Neurological and Neurosurgical Hospital – Hospices Civils de Lyon, Lyon, France T. Jacquesson : E. Jouanneau Research and Education Unit of Medicine, Claude Bernard University Lyon 1, Lyon, France L. Abouaf Department of Neuro-ophthalmology (Pr A Vighetto), Pierre Wertheimer Neurological and Neurosurgical Hospital – Hospices Civils de Lyon, Lyon, France
Key points • Nasal and sphenoidal anatomies determine the feasibility and risks for doing an efficient medial optic or orbit decompression. • Techniques and tools used are those developed for pituitary surgery. • A middle turbinectomy and posterior ethmoidectomy are mandatory to expose the medial wall of the orbit. • The Onodi cell is a key marker for the optic canal and must be opened up with caution. • The lamina papyracea is opened first with a spatula and the optic canal opened up by a gentle drilling under continuous irrigation from distal to proximal. • Drilling might always be used under continuous irrigation to avoid overheating of the optic nerve. An ultrasonic device can be used as well. • The nasal corridor is narrow and instruments may hide the infrared neuronavigation probe. To overcome this issue, a magnetic device could be useful. • Doppler control could be useful to locate the ICA. • The optic canal must be opened up from the tuberculum of the sella to the orbital apex and from the planum (anterior cranial fossa) to the lateral OCR or ICA canal • At the end of the procedure, the optic nerve becomes frequently pulsatile, which is a good marker of decompression. Keywords Skull base surgery . Minimally invasive neurosurgery . Endoscopic endonasal surgery . Optic nerve tumors . Orbital Tumors . Trans-sphenoidal approach
E. Jouanneau INSERM U1028, CNRS UMR5292, Neurosciences Research Center of Lyon, Neuro-oncology and Neuro-inflammation team, Lyon, France
Introduction
T. Jacquesson (*) Skull Base Surgery Unit – Department of Neurosurgery A, Pierre Wertheimer Neurological and Neurosurgical Hospital – Hospices Civils de Lyon, 59 Boulevard Pinel, 69394 Lyon, Cedex 03, France e-mail: [email protected]
With the development of the technique, endoscopic endonasal surgery increases its field of application both for treating diseases and accessing challenging anatomical locations [1]. Routinely used for pituitary surgery, the endoscopic naso-
1892
Acta Neurochir (2014) 156:1891–1896
Fig. 1 a: Anatomical view view of the sphenoid sinus. DM: duramater of the sella turcica; OP: optic Prominence; CP: carotid prominence; OCR: Lateral Optico Carotid Recess; PS: Planum Sphenoidal. b: anatomical data after large opening of the sphenoid and ethmoidal sinuses. ON: Optic Nerve; C5 ICA: C5 portion of the Internal Carotid; ST: Sella Turcica
sphenoidal route provides minimally-invasive access to the medial compartment of the orbit and the optic nerve. This has been underused for tumoral diseases [10, 9]. Thus, a visual impairment can result from compression due to inextensible bony walls. The extradural approach with the aperture of the optic canal, anterior clinoidectomy, or lateral orbitotomy is routinely performed for decompression, with some morbidity [7] and the medial nasal approach represents another option. This route can also be used for tumor biopsy or removal, although inadequate instrumentation still prevents expansion of indications [3]. We describe the tips and tricks for optic and orbital endoscopic endonasal decompression.
Nasal phase A uninostril approach, on the same side of the optic nerve or orbit we want to reach, is used. A 0° short rigid endoscope (18 cm length, 4 mm diameter, Storz®, Tuttlingen, Germany) is introduced inside the nostril and a middle turbinectomy is first done followed by a posterior ethmoidectomy (Fig. 2 a and b). Sphenoidal phase The mucosa is coagulated medially to the sphenoid ostium and the posterior bony septum is pushed away until the contralateral ostium can be seen. The vomer is then removed using a bone forceps, and the sphenoidotomy is enlarged laterally to expose the optic nerve and ICA (Fig. 1a).
Relevant surgical anatomy Orbital apex and optic canal opening Lateral to the sella turcica is the optic canal (OC) with the C5 paraclinoid portion of the Internal Carotid Artery (ICA) (Fig. 1a). The medial and lateral optico-carotid recesses respectively correspond to the middle and the anterior clinoid processes. The OC is in close contact with the Onodi Cell (the most posterior ethmoidal cell) (Fig. 2 a and b). The orbital apex prolongs anteriorly along the OC and lies above the superior orbital fissure (Fig. 1b). The orbit is limited medially by the laminae papyracea (cells of the lateral massa of the ethmoid) (Fig. 2a) and inferiorly by the maxillary sinus.
When starting to work around the optic nerve, a long endoscope (30 cm) is positioned in the upper part of the nostril and secured in the holder. The surgical tools can be passed below the endoscope. The thin lamina papyracea is first opened up with a spatula. The opening of the OC is done from distal to proximal to the tuberculum of the sella by a gentle drilling, and the bone pellicle is finally removed with a spatula or with a bone punch. The OC aperture must be as large as possible, especially at the superior and inferior parts of the OC until the planum and the OCR, respectively. A clockwise 180° of freedom of the optic nerve may be expected (Fig. 3 a and b). The medial orbital decompression can be extended as anteriorly as needed according to the tumor anatomy (Fig. 4).
Description of the technique
Closure and postoperative care
Positioning and anesthesia
Sinuses and the nostril are cleaned with saline solution and the hemostasis checked. No nasal packing is needed. Postoperatively, no intensive care is needed. Vision and nasal flow are regularly checked for the first few days. A CT
The patient’s positioning and pre-operative steps are similar to regular pituitary cases and have been previously described [2].
Acta Neurochir (2014) 156:1891–1896
1893
Fig. 2 a: cranio-facial axial CT showing the thin lamea papyracea, the medial wall of the orbit, and the OC (Onodi Cell) posterior ethmoidal cell in direct contact with the ON (Optic Nerve). b: Cranio-facial coronal CT showing the OC and the ON
scan is done on day one and the patient is discharged from the hospital at day three. An endoscopic nasal check-up is done within three weeks after the surgery. Visual and MRI evaluation is planned at three months and thereafter, depending on the underlying disease.
Indications (Fig. 4) Inflammatory (Grave’s orbitopathy) or traumatic diseases represent traditional indications of endonasal orbital decompression [5, 8]. Fig. 3 a: Operative view of the sphenoid sinus with the ON (Optic Nerve), the Orbital apex, the C5 ICA (C5 portion of the ICA), the TS (tuberculum of the Sella) and the planum. b: Operative view after the optic nerve and the orbital apex decompression. The DM (DuraMater) of the planum and the TS (Tuberculum of the Sella) have been exposed to ensure a complete optic decompression
This may also be discussed in the case of tumors of the optic nerve or orbital apex, mainly for meningiomas when a visual impairment occurs (Fig. 5). For spheno-orbital meningiomas, this approach can be used first to decompress the optic nerve before doing the regular lateral orbitotomy. Indeed, in many cases, the hyperostosis stays lateral, and this may reduce optic nerve suffering during the second procedure. This approach can also be used to realize tumor biopsies or removal when the tumors are located medially into the orbit.
1894
Acta Neurochir (2014) 156:1891–1896
Fig. 4 Examples of tumors that may benefit from an endonasal endoscopic surgery. a: Optic nerve sheath meningioma. b: Optic nerve sheath meningioma. c: Spheno-orbital meningioma
Limitations Complex sphenoid septa and/or weak pneumatization can lead to exposure difficulties with time-consuming and risky drilling [4]. The same difficulties can be encountered in cases of medial hyperostosis. As soon as the periorbita is opened up, the orbital fat and muscles get out. Thus, orbital tumors may be hard to identify and remove, as retractors for orbital content are still missing.
– –
The surgeon may be aware that the ophthalmic artery can emerge from the medial or inferior part of the optic canal in cases of biopsy or removal [6]. Dura mater of the anterior skull base is fragile in this location and must be pushed away when drilling to avoid a CSF leak.
Specific perioperative considerations How to avoid complications –
– – –
Pre-operative assessment of imaging exams (CT-scan and MRI, angioMRI) must study the anatomy to anticipate surgical difficulties (megaturbinates, septal deviation, sphenoid pneumatization and septas, length of the OC, hyperostosis, ICA positioning). Careful opening of the Onodi cell is mandatory to avoid ON injury. Keeping the bone of the C5 ICA canal intact is useful to decrease the vascular risk when opening the inferior part of the optic canal. Posterior ethmoidal arteries must be identified.
Preoperatively, a cranio-facial CT and MRI are done and used for neuronavigation during the surgery. Mandatorily, a visual assessment includes bilateral visual acuity, fundoscopy, and computerized visual field. A rigorous preoperative preparation is systematic, including nasal rinsing and iodine ointment the day before and just before surgery. Postoperatively, no intensive care is needed. Vision as well as nasal flow are checked every two hours the first night and twice daily thereafter. A Ct scan is done at day one and the patient is dischargesd from the hospital at day two or three. An endoscopic nasal check-up is done within two or three weeks after the surgery to control mucosae and sinus
Acta Neurochir (2014) 156:1891–1896
1895
Fig. 5 a and b: Ophthalmologic results before (up) and after (down) an endonsasal endoscopic optic nerve and orbital apex decompression for a sphenoorbital meningioma (decompression between the two arrows). Both the visual acuity and field have been improved
healing. Postoperative visual and MRI evaluation is planned at three months and thereafter depending on the underlying disease.
available instrumentation, particularly orbital fat retractors and angled instruments.
Specific information to give to the patient
Conflict of interest None.
Patients have to be aware of potential visual and vascular risks. As for pituitary surgery, the postoperative rhinological discomfort and CSF leak rate are very minimal. Finally, the patient must be aware that coughing, sneezing, or blowing the nose may result in exophthalmia because of air getting into the orbit and, therefore, should be avoided during the first days.
References
Conclusion The nasal route is a smart one for reaching the optic or orbital compartments for various diseases but is still underused for tumoral ones. This may represent an easy way to decompress the optic canal or orbital apex in case of medial tiny bone but needs specific training and materials. Further evaluations of functional results are required. Tumor biopsies can also be done but tumor removal still requires a refinement of the
1. Berhouma M, Messerer M, Jouanneau E (2012) Shifting paradigm in skull base surgery: Roots, current state of the art and future trends of endonasal endoscopic approaches. Rev Neurol (Paris) 168(2):121– 134 2. Berhouma M, Messerer M, Jouanneau E (2012) Occam’s razor in minimally invasive pituitary surgery: tailoring the endoscopic endonasal uninostril trans-sphenoidal approach to sella turcica. Acta Neurochir (Wien). doi:10.1007/s00701-012-1510-2 3. Cebula H, Lahlou A, De Battista JC, Debry C, Froelich S (2010) Endoscopic approaches to the orbit. Neurochirurgie 56(2–3):230– 235 4. Hart CK, Theodosopoulos PV, Zimmer LA (2009) Anatomy of the optic canal: a computed tomography study of endoscopic nerve decompression. Ann Otol Rhinol Laryngol 118(12):839–844 5. Jiang RS, Hsu CY, Shen BH (2001) Endoscopic optic nerve decompression for the treatment of traumatic optic neuropathy. Rhinology 39(2):71–74
1896 6. Locatelli M, Caroli M, Pluderi M, Motta F, Gaini SM, Tschabitscher M, Scarone P (2011) Endoscopic transsphenoidal optic nerve decompression: an anatomical study. Surg Radiol Anat 33(3):257–262 7. Mariniello G, Bonavolontà G, Tranfa F, Maiuri F (2013) Management of the optic canal invasion and visual outcome in spheno-orbital meningiomas. Clin Neurol Neurosurg 115(9):1615–1620 8. Michel O, Oberländer N, Neugebauer P, Neugebauer A, Rüssmann W (2001) Follow-up of transnasal orbital
Acta Neurochir (2014) 156:1891–1896 decompression in severe Graves’ ophthalmopathy. Ophthalmology 108(2):400–404 9. Netuka D, Masopust V, Belšán T, Profantová N, Beneš V (2013) Endoscopic endonasal resection of medial orbital lesions with intraoperative MRI. Acta Neurochir (Wien) 155(3):455–461 10. Sia DIT, Chan WO, Wormald PJ, Davis G, Selva D (2012) Decompression of benign orbital apex lesion via medial endoscopic approach. Orbit 31(5):344–346
