Anterior clinoidectomy

Anterior clinoidectomy

The optic nerve within the optic canal, the parophthalmic segment of the internal carotid artery, and the oculomotor nerve in the superior orbital fissure all lay against the anterior clinoid process. Bone resection uncovers these structures.


Removal of the anterior clinoid process(ACP) facilitates radical removal of tumors or radical neck clipping of aneurysms in the suprasellar region and parasellar regions by providing a wide operative exposure of the internal carotid artery (ICA) and the optic nerve and by reducing the need for brain retraction.

Preoperative imaging of anterior clinoid region meningioma can accurately predict the presence or absence of tumor involvement of the clinoid in only approximately 75% of cases. In light of the fact that a quarter of patients with radiographically negative clinoids will have tumor present on pathological analysis, Copeland et al. recommend a clinoidectomy for all anterior clinoid region meningioma1).

Initially developed intradurally 2) 3) , later extradural 4).


A high-speed power-drilling technique of anterior clinoidectomy has been advocated in all publications on paraclinoid region surgery. The entire shaft of the power drill is exposed in the operative field; thus, all neurovascular structures in proximity to any portion of the full length of the rotating drill bit are at risk for direct mechanical and/or thermal injury. Ultrasonic bone removal has recently been developed to mitigate the potential complications of the traditional power-drilling technique of anterior clinoidectomy. However, ultrasound-related cranial neuropathies are recognized complications of its use, as well as the increased cost of device acquisition and maintenance.

see Endoscopic extradural anterior clinoidectomy.

Extradural clinoidectomy

Extradural removal of the anterior clinoid process (ACP) is a crucial step in the proper surgical exposure of various pathologies in and around the central skull base. Since the pioneering description by Vinko Dolenc, the technique of extradural clinoidectomy has undergone several refinements in the light of improved understanding of microsurgical anatomy and maturation of neurosurgical techniques 5).

Noguchi et al., in 2005 compared the original Dolenc procedure and its subsequent derivatives with their own simpler and less laborious technique. Different clinical situations in which to use the procedure were described based on the authors’ experience from 60 cases (40 aneurysm cases and 20 tumor cases) during a 4-year period 6).

For extradural resection of the anterior clinoid process and surrounding bone, two key steps are recommended: bony opening of the superior orbital fissure, and transection of the orbitotemporal periosteal fold.

Key Points: Pterional craniotomy • Complete extradural anterior clinoidectomy • Slit dura (3 mm) to drain cerebrospinal fluid • Peel dura from orbital roof and lateral wall • Bony opening of superior orbital fissure to use it as surgical corridor • Drilling of optic canal • Transection of orbitotemporal periosteal fold • Hollow anterior clinoid process and piece-meal resection • Transection of falciforme ligament to free optic nerve • Replace falciforme ligament by extradural free pericranial flap 7).

Hybrid technique

It is important to note that the surgeon should prefer the method he or she feels most comfortable with. This preference is often affected by the surgeon’s training. Extradural clinoidectomy is advantageous during removal of the medial sphenoid wing meningiomas as aggressive bony removal facilitates extradural devascularization of the tumor and may enhance gross tumor removal, especially if the clinoid is infiltrated with tumor. The intradural technique may be preferred for clipping of ophthalmic aneurysms as bony removal can be tailored based on the pathology at hand and clinoidectomy can be done under careful monitoring of the aneurysm to prevent manipulations that would place the aneurysm at risk of intraoperative rupture.

The hybrid method theoretically can be used as a versatile method under both circumstances mentioned above. Cutting the dura along the sphenoid wing will prevent the dural layers from obscuring the clinoid and offers intradural visualization to monitor the lesion and potentially tailor bony removal. 8).

In a study, Tayebi Meybodi et al., sought to develop a hybrid technique based on localization of the optic strut (OS) to combine the advantages and avoid the disadvantages of both techniques. Ten cadaveric specimens were prepared for surgical simulation. After a standard pterional craniotomy, the anterior clinoid process (ACP) was resected in 2 steps. The segment anterior to the OS was resected extradurally, while the segment posterior to the OS was resected intradurally. The proposed technique was performed in 6 clinical cases to evaluate its safety and efficiency. Anterior clinoidectomy was successfully performed in all cadaveric specimens and all 6 patients by using the proposed technique. The extradural phase enabled early decompression of the optic nerve while avoiding the adjacent internal carotid artery. The OS was drilled intradurally under direct visualization of the adjacent neurovascular structures. The described landmarks were easily identifiable and applicable in the surgically treated patients. No operative complication was encountered. A proposed 2-step hybrid technique combines the advantages of the extradural and intradural techniques while avoiding their disadvantages. This technique allows reduced intradural drilling and subarachnoid bone dust deposition. Moreover, the most critical part of the clinoidectomy-that is, drilling of the OS and removal of the body of the ACP-is left for the intradural phase, when critical neurovascular structures can be directly viewed 9).


Extradural anterior clinoidectomy is a versatile technique to increase exposure of the sellar and parasellar region. It is of particular use in the resection of clinoidal meningiomas, as sphenoidal and clinoidal hyperostosis can cause compression of the optic nerve. Extradural clinoidectomy follows a series of steps, consisting of (1) unroofing of the superior orbital fissure, (2) unroofing of the optic canal, (3) removal of the optic strut, and (4) removal of the anterior clinoid process. The authors show these steps in detail, as well as their application to the resection of a large clinoidal meningioma. The video can be found here: 10).

Case series


Between June 2007 and January 2011, a total of 82 patients with neoplastic and vascular lesions underwent anterior clinoidectomy by the senior author (J.H.) through the LSO approach. They analyzed the operative videos paying particular attention to the surgical technique used for removal of the anterior clinoid process (ACP) and compared the microsurgical nuances to postoperative complications related to anterior clinoidectomy.

Forty-five patients were treated for aneurysms; 35 patients for intraorbital, parasellar, and suprasellar tumors; and 2 patients for carotid-cavernous fistulas. Intradural anterior clinoidectomy was performed in 67 (82%) cases; in 15 (18%) cases an extradural approach was used. In 51 (62%) cases, ACP was removed completely, whereas in the remaining 31 (38%) a tailored anterior clinoidectomy was performed. Four (5%) patients had new postoperative visual deficits and 3 (4%) experienced a worsening of preoperative visual deficits. Twelve (15%) patients improved their preoperative visual deficits after intradural anterior clinoidectomy. Ultrasonic bone device is a useful tool but may damage the optic nerve when performing anterior clinoidectomy. There was no mortality in our series.

Anterior clinoidectomy can be performed through an LSO approach with a safety profile that is comparable to other approaches. Ultrasonic bone dissector is a useful tool but may lead to injury of the optic nerve and should be used very carefully in its vicinity 11).


A retrospective review of a cerebrovascular/cranial base fellowship-trained neurosurgeon’s 45 consecutive cases of anterior clinoidectomy using the “no-drill” technique is presented. Clinical indications have been primarily small to giant aneurysms of the proximal internal carotid artery; however, in addition to ophthalmic segment aneurysms, selected internal carotid artery-posterior communicating artery aneurysms and internal carotid artery bifurcation aneurysms, and other large/giant/complex anterior circulation aneurysms, this surgical series of “no-drill” anterior clinoidectomy includes tuberculum sellae meningiomas, clinoidal meningiomas, cavernous sinus lesions, pituitary macroadenomas with significant suprasellar extension, other perichiasmal lesions (sarcoid), and fibrous dysplasia. A bony opening is made in the mid-to posterior orbital roof after the initial pterional craniotomy. Periorbita is dissected off the bone from inside the orbital compartment. Subsequent piecemeal resection of the medial sphenoid wing, anterior clinoid process, optic canal roof, and optic strut is performed with bone rongeurs of various sizes via the bony window made in the orbital roof. RESULTS: No power drilling was used in this surgical series of anterior clinoidectomies. Optimal microsurgical exposure was obtained in all cases to facilitate complete aneurysm clippings and lesionectomies. There were no cases of direct injury to surrounding neurovascular structures from the use of the “no-drill” technique. The surgical technique is presented with illustrative clinical cases and intraoperative photographs, demonstrating the range of applications in anterior and central cranial base neurosurgery. CONCLUSION: Power drilling is generally not necessary for removal of the anterior clinoid process, optic canal roof, and optic strut. Rigorous study of preoperative computed tomographic scans/computed tomographic angiography scans, magnetic resonance imaging scans, and angiograms is essential to identify important anatomic relationships between the anterior clinoid process, optic strut, optic canal roof, and neighboring neurovascular structures. The “no-drill” technique eliminates the risks of direct power-drilling mechanical/ thermal injury and the risks of ultrasound-associated cranial neuropathies. The “no-drill” technique provides a direct, time-efficient, and efficacious approach to the paraclinoid/ parasellar/pericavernous area, using a simplified mechanical route. This technique is applicable to any neurosurgical diagnosis and approach in which anterior clinoidectomy is necessary. It is arguably the gentlest and most efficient method for exposing the paraclinoid/parasellar/pericavernous region 12).


Over a period of 3 years, anterior clinoidectomy was performed in 40 patients, 30 of whom harbored aneurysms (18 of the ICA and 13 of the basilar artery [one patient had two aneurysms]) and 10 of whom had tumors (four large pituitary tumors, four craniopharyngiomas, and two sphenoid ridge meningiomas). The ACP was removed extradurally in 31 cases and intradurally in nine cases. Extradural clinoidectomy was performed in all cases of pituitary adenoma and craniopharyngioma and in most cases of basilar artery aneurysm. Intradural clinoidectomy was performed in two cases of ICA-ophthalmic artery aneurysm, two cases of ICA-posterior communicating artery aneurysm, two cases of ICA cavernous aneurysm, one case of basilar artery aneurysm, and two cases of sphenoid ridge meningioma. The outcome was satisfactory in all patients, except for one patient who underwent clipping of a basilar tip aneurysm and suffered a thalamic and midbrain infarction. Three patients who underwent extradural clinoidectomy suffered a postoperative diminution of visual acuity or a visual field defect on the side of the clinoidectomy. These deficits may have been caused either by drilling of the ACP or by other operative manipulation of the optic nerve. Cerebrospinal fluid rhinorrhea, which required reoperation, occurred in one patient. The authors’ experience suggests that the extradural technique of ACP removal is easier and less time consuming than the intradural one and provides better operative exposure. It can be used routinely in treating lesions in the supra- and parasellar region 13).



Copeland WR, Van Gompel JJ, Giannini C, Eckel LJ, Koeller KK, Link MJ. Can Preoperative Imaging Predict Tumor Involvement of the Anterior Clinoid in Clinoid Region Meningiomas? Neurosurgery. 2015 Oct;77(4):525-30. doi: 10.1227/NEU.0000000000000873. PubMed PMID: 26120799.

Drake CG, Vanderlinden RG, Amacher AL. Carotid-ophthalmic aneurysms. J Neurosurg. 1968;29:24–31.

Hauser MJ, Gass H. Optic nerve pressure by aneurysm relieved by decompression of optic nerve; report of a case. AMA Arch Ophthalmol. 1952;48:627–31.

Dolenc VV. A combined epi- and subdural direct approach to carotid-ophthalmic artery aneurysms. J Neurosurg. 1985;62:667–72.

Mishra S, Leão B, Rosito DM. Extradural anterior clinoidectomy: Technical nuances from a learner’s perspective. Asian J Neurosurg. 2017 Apr-Jun;12(2):189-193. doi: 10.4103/1793-5482.145544. PubMed PMID: 28484528; PubMed Central PMCID: PMC5409364.

Noguchi A, Balasingam V, Shiokawa Y, McMenomey SO, Delashaw JB Jr. Extradural anterior clinoidectomy. Technical note. J Neurosurg. 2005 May;102(5):945-50. PubMed PMID: 15926728.

Lehmberg J, Krieg SM, Meyer B. Anterior clinoidectomy. Acta Neurochir (Wien). 2014 Feb;156(2):415-9; discussion 419. doi: 10.1007/s00701-013-1960-1. Epub 2013 Dec 10. Review. PubMed PMID: 24322583.

Kulwin C, Tubbs RS, Cohen-Gadol AA. Anterior clinoidectomy: Description of an alternative hybrid method and a review of the current techniques with an emphasis on complication avoidance. Surg Neurol Int. 2011;2:140. doi: 10.4103/2152-7806.85981. Epub 2011 Oct 12. PubMed PMID: 22059135; PubMed Central PMCID: PMC3205487.

Tayebi Meybodi A, Lawton MT, Yousef S, Guo X, González Sánchez JJ, Tabani H, García S, Burkhardt JK, Benet A. Anterior clinoidectomy using an extradural and intradural 2-step hybrid technique. J Neurosurg. 2018 Feb 23:1-10. doi: 10.3171/2017.8.JNS171522. [Epub ahead of print] PubMed PMID: 29473783.

Buttrick S, Morcos JJ, Elhammady MS, Wang AC. Extradural clinoidectomy for resection of clinoidal meningioma. Neurosurg Focus. 2017 Oct;43(VideoSuppl2):V10. doi: 10.3171/2017.10.FocusVid.17363. PubMed PMID: 28967317.

Romani R, Elsharkawy A, Laakso A, Kangasniemi M, Hernesniemi J. Complications of anterior clinoidectomy through lateral supraorbital approach. World Neurosurg. 2012 May-Jun;77(5-6):698-703. doi: 10.1016/j.wneu.2011.08.014. Epub 2011 Nov 7. PubMed PMID: 22120307.

Chang DJ. The “no-drill” technique of anterior clinoidectomy: a cranial base approach to the paraclinoid and parasellar region. Neurosurgery. 2009 Mar;64(3 Suppl):ons96-105; discussion ons105-6. doi: 10.1227/01.NEU.0000335172.68267.01. PubMed PMID: 19240577.

Yonekawa Y, Ogata N, Imhof HG, Olivecrona M, Strommer K, Kwak TE, Roth P, Groscurth P. Selective extradural anterior clinoidectomy for supra- and parasellar processes. Technical note. J Neurosurg. 1997 Oct;87(4):636-42. PubMed PMID: 9322855.

Cervical PEEK Cage

Cervical PEEK Cage


Common interbody graft options for anterior cervical discectomy and fusion(ACDF) include structural allograft and polyetheretherketone (PEEK). PEEK has gained popularity due to its radiolucency and its elastic modulus, which is similar to that of bone.

A study provided strong evidence that ACDF is effective treatment, but the overall rate of radiographic fusion with empty PEEK cages is slow and insufficient. Lack of complete radiographic fusion leads to less improvement of pain and disability. The study recommended against using empty uncoated pure PEEK cages in ACDF 1).

Studies comparing cervical titanium cages and PEEK cages are rare in the literature. Chou’s team retrospectively compared the results of anterior cervical fusion using titanium cages, PEEK cages and tricortical bone grafts 2). They noticed a better fusion rate and less subsidence in the PEEK cages group. However, the study only enrolled a small number of patients and cervical spinal function was not evaluated. In a systematic review by Kersten who compared a PEEK cage with a bone graft, titanium cage, and carbon fiber cage, no difference was found between PEEK and titanium cage 3).

meta-analysis indicated no significant difference in functional and radiographic performance between the PEEK and titanium cages, although more subsidence occurred in the titanium cage group. More high-quality studies are needed to confirm these results to offer more information for the choice in clinical practice 4).

A study sought to compare the rates of pseudarthrosis, a lack of solid bone growth across the disc space, and the need for revision surgery with the use of grafts made of allogenic bone versus PEEK.

127 cases in which patients had undergone a 1-level ACDF followed by at least 1 year of radiographic follow-up. Data on age, sex, body mass indextobacco use, pseudarthrosis, and the reoperation rate for pseudarthrosis were collected. These data were analyzed by performing a Pearson’s chi-squared test.

Of 127 patients, 56 had received PEEK implants and 71 had received allografts. Forty-six of the PEEK implants (82%) were stand-alone devices. There were no significant differences between the 2 treatment groups with respect to patient age, sex, or body mass index. Twenty-nine (52%) of 56 patients with PEEK implants demonstrated radiographic evidence of pseudarthrosis, compared to 7 (10%) of 71 patients with structural allografts (p < 0.001, OR 9.82; 95% CI 3.836-25.139). Seven patients with PEEK implants required reoperation for pseudarthrosis, compared to 1 patient with an allograft (p = 0.01, OR 10.00; 95% CI 1.192-83.884). There was no significant difference in tobacco use between the PEEK and allograft groups (p = 0.586).

The results of this study demonstrate that the use of PEEK devices in 1-level ACDF is associated with a significantly higher rate of radiographically demonstrated pseudarthrosis and need for revision surgery compared with the use of allografts. Surgeons should be aware of this when deciding on interbody graft options, and reimbursement policies should reflect these discrepancies 5).

The aim of a study is to compare silicon nitride implants with PEEK cages filled with autograft harvested from osteophytes.

A prospective, randomized, blinded study of 100 patients with 2 years follow-up. The primary outcome measure was improvement in the Neck Disability Index. Other outcome measures included SF-36, VAS arm pain, VAS neck pain, assessment of recovery, operative characteristics, complications, fusion and subsidence based on dynamic X-ray and CT scan.

There was no significant difference in NDI scores between the groups at 24 months follow-up. At 3 and 12 months the NDI scores were in favor of PEEK although the differences were not clinically relevant. On most follow-up moments there was no difference in VAS neck and VAS arm between both groups, and there was no statistically significant difference in patients’ perceived recovery during follow-up. Fusion rate and subsidence were similar for the two study arms and about 90% of the implants were fused at 24 months.

Patients treated with silicon nitride and PEEK reported similar recovery rates during follow-up. There was no significant difference in clinical outcome at 24 months. Fusion rates improved over time and are comparable between both groups 6).


Aves Cervical Bladed Peek Cage

AYERS ROCK Spineway France

CAP Cervical H.P.I. Medical France





Cervical PEEK cage Coroent

Genoss Integral Cervical Cage™

LorX® Expandable Cervical Peek Cage with Blade

PROYSTER® Prodorth

Reborn® Cervical PEEK Cage

ROI-C cervical cage (LDR)


SAS 9® Biotechni France



Zero P (Synthes, Inc.)….

Case series

see Cervical PEEK Cage case series


1) Suess O, Schomaker M, Cabraja M, Danne M, Kombos T, Hanna M. Empty polyetheretherketone (PEEK) cages in anterior cervical diskectomy and fusion (ACDF) show slow radiographic fusion that reduces clinical improvement: results from the prospective multicenter “PIERCE-PEEK” study. Patient Saf Surg. 2017 Apr 28;11:12. doi: 10.1186/s13037-017-0128-y. eCollection 2017. PubMed PMID: 28465721; PubMed Central PMCID: PMC5410058.2) Chou YC, Chen DC, Hsieh WA, Chen WF, Yen PS, Harnod T, Chiou TL, Chang YL, Su CF, Lin SZ, Chen SY. Efficacy of anterior cervical fusion: comparison of titanium cages, polyetheretherketone (PEEK) cages and autogenous bone grafts. J Clin Neurosci. 2008 Nov;15(11):1240-5. doi: 10.1016/j.jocn.2007.05.016. Epub 2008 Sep 17. PubMed PMID: 18801658.3) Kersten RF, van Gaalen SM, de Gast A, Öner FC. Polyetheretherketone (PEEK) cages in cervical applications: a systematic review. Spine J. 2015 Jun 1;15(6):1446-60. doi: 10.1016/j.spinee.2013.08.030. Epub 2013 Dec 27. Review. PubMed PMID: 24374100.4) Li ZJ, Wang Y, Xu GJ, Tian P. Is PEEK cage better than titanium cage in anterior cervical discectomy and fusion surgery? A meta-analysis. BMC Musculoskelet Disord. 2016 Sep 1;17:379. doi: 10.1186/s12891-016-1234-1. PubMed PMID: 27585553; PubMed Central PMCID: PMC5009677.5) Fivefold higher rate of pseudarthrosis with polyetheretherketone interbody device than with structural allograft used for 1-level anterior cervical discectomy and fusion. J Neurosurg Spine. 2018 Oct 1:1-6. doi: 10.3171/2018.7.SPINE18531. [Epub ahead of print] PubMed PMID: 30485200.6) Arts MP, Wolfs JF, Corbin TP. Porous silicon nitride spacers versus PEEK cages for anterior cervical discectomy and fusion: clinical and radiological results of a single-blinded randomized controlled trial. Eur Spine J. 2017 Apr 5. doi: 10.1007/s00586-017-5079-6. [Epub ahead of print] PubMed PMID: 28382392.

360-Degree Skull Base Course


Strasbourg, France

The courses will take place in our IRCAD Institute in Strasbourg, France (

This full immersion workshop is intended for neurosurgeons or ENTs from the world over, who wish to learn and practice the technical skills required for skull base surgery. It has been structured to provide didactic lectures, surgical videos, and over 27 hours of hands-on cadaver dissection sessions, covering a broad spectrum of transcranial keyhole, endoscopic, endonasal and combined approaches. A panel of prominent leaders in these fields of expertise will deliver lectures focusing on skull base anatomy, transcranial, endoscopic assisted and endoscopic endonasal approaches as well as therapeutic strategies for skull base lesions. The scientific program will include a guest speaker session on a topic related to skull base neurosurgery, with lectures delivered by world-renowned experts. Topics previously discussed included acoustic neuroma, microvascular decompression, radiosurgery for skull base lesions, pediatric skull base neurosurgery, brainstem cavernomas, chordomas, revascularization and reconstruction techniques. Attendees will benefit from more than 27 hours of hands-on dissection in the outstanding IRCAD surgical lab environment with state-of-the-art equipment provided by our dedicated sponsors. For hands-on sessions, a live demonstration will be performed at the master station, broadcasted on a 3D screen and at each workstation. In the meantime, participants will work in pairs on prepared injected fixed specimens, under the guidance of a distinguished expert faculty.

Course higlights:

– Full immersion

– 27 hours of hands-on practice

– Didactic lectures and videos from world-renowned experts

– Live 3D demonstration broadcast at each station

– Full HD camera, microscope, endoscope and exoscope

– High-speed drill, neuronavigation, headholders, adequate instrumentation for all

– Outstanding facilities

WhatsApp WhatsApp us
%d bloggers like this: