Clinoidectomía anterior intradural para clipado de aneurisma paraclinoideo izquierdo: video quirúrgico / Anterior intradural clinoidectomy for clipping left paraclinoid aneurysm: surgical video

Introducción: Los aneurismas paraclinoideos representan un verdadero desafío microquirúrgico para su resolución. Objetivo: Presentamos el caso de una mujer de 43 años de edad con cefalea, detectando en angiografía aneurisma paraclinoideo izquierdo. Material y métodos: Se realizó abordaje pterional izquierdo y exposición de carótida interna a nivel cervical, durotomía arciforme con apertura de cisterna silviana hacia cisterna carotídea. Se expone la apófisis clinoides anterior, observándose en el video, el aneurisma naciendo del segmento clinoideo de la arteria carótida interna, siendo imposible el clipado de la misma sin clinoidectomía anterior. Se secciona la duramadre desde medial respecto al conducto óptico hasta la apófisis clinoides. Se realiza fresado en la base de la apófisis clinoides para exponer el anillo dural distal. Se libera la carótida en el segmento clinoideo a través de la sección del anillo dural distal para poder movilizarla. Identificado el cuello distal y proximal del aneurisma, se comienza la reconstrucción colocando un clip a 90° en dirección anteroposterior, un segundo clip en dirección posteroanterior y al punzar el aneurisma se constata flujo aneurismático presente. Se coloca un tercer y cuarto clip en tándem desde la proximidad a la carótida interna hacia el domo del aneurisma. Finalmente se posiciona un quinto clip curvo sobre los anteriores para darles mayor presión de cierre. Resultados: Se observa angiografía postoperatoria con exclusión completa el aneurisma con adecuada permeabilidad carotidea. El período postoperatorio fue excelente, sin déficit neurológico. La paciente brindo consentimiento para publicar sus imágenes y videos.

Introduction: Paraclinoid aneurysms represent a true microsurgical challenge. Objective: We present the case of a 43-year-old woman with headache, in whom a left paraclinoid aneurysm was detected by angiography. Methods and Materials: A left pterional approach was adopted, combined with exposing the internal carotid artery at the cervical level, and an arciform durotomy with the opening of the sylvian fissure to the carotid cistern. The anterior clinoid process was exposed, revealing the aneurysm originating from the clinoid segment of the carotid artery; consequently, clipping was impossible without an anterior clinoidectomy. The dura was cut medially from the optic canal to the clinoid process. Drilling was performed at the base of the clinoid process to expose the distal carotid dural ring. The carotid was released in the clinoid segment by sectioning the distal dural ring to mobilize it. After identifying the distal and proximal neck of the aneurysm, reconstruction was initiated by placing a 90-degree clip in the anteroposterior direction; then, a second clip in the posteroanterior direction and puncturing the aneurysm, demonstrating that aneurysmal flow was present. Third and fourth clips were placed in tandem, one proximal to the internal carotid and the other at the dome of the aneurysm. Finally, a fifth curved clip was placed over the previous clips to increase their closure pressure. Results: Postoperative angiography revealed complete exclusion of the aneurysm with adequate carotid permeability. The postoperative period lacked any complications or neurological deficits. The patient consented to have her images and videos published. Conclusions: Combining a left pterional approach with exposing the internal carotid artery at the cervical level and performing an arciform durotomy at the sylvian fissure's opening into the carotid cistern, an angiographically-detected left paraclinoid aneurysm was treated successfully with an excellent outcome.

Impact of Anterior Clinoid Process Pneumatization on Adjacent Anatomical Structures

The Anterior clinoid process is closely related to many important anatomical structures including vessels, nerves, and paranasal sinuses. In the majority of cases, this process is osseous, but its pneumatization has been recorded as an anatomic variant. Coronal CT scans of the head region that were done for thirty-seven patients at Tanta University hospitals were collected to be used in teaching radiological anatomy for medical students. During their routine investigation, a case of a female aged 21 years showed bilateral pneumatization of the anterior clinoid processes associated with some variants of the adjacent anatomical structures. These findings were discussed on anatomical basis with referral to their possible clinical implications. If a surgical removal of the anterior clinoid process is recommended, a comprehensive knowledge of its anatomy, pneumatization, and associated regional anatomic variants is crucial for neurosurgeons to avoid risky complications.

Aneurismas paraclinoideos: experiencia personal de 1 año en el Hospital Regional de Temuco / Paraclinoid aneurysm: 1 year personal experience at Hospital Regional de Temuco

Se presenta la experiencia personal en el tratamiento de 5 pacientes con 7 aneurismas paraclinoideos tratados quirúrgicamente en el Hospital Regional Temuco durante junio de 2015 y julio de 2016 (13 meses). Todos los pacientes fueron previamente discutidos con neurorradiologo Intervencional local y considerados no favorables para terapia endovascular. En todos ellos se realizó una craneotomía mini pterional con clinoidectomía extradural y exposición de la arteria carótida interna cervical. Cuatro pacientes consultaron con hemorragia subaracnoidea y requirieron cirugía cerebral de urgencia. En 6 aneurismas se realizó clipaje y en 1 trapping. Cuatro pacientes no tuvieron deterioro neurológico y evolucionaron favorablemente mientras que 1 paciente falleció por hipoperfusión secundario al trapping de la carótida supraclinoidea. Se enfatiza el manejo interdisciplinario, el plan preoperatorio y el conocimiento de la neuroanatomía en el tratamiento de esta patología.

A personal experience is presented in treating 5 patients with 7 paraclinoid aneurysm who underwent surgery at Hospital Regional Temuco between june 2015 and july 2016 (13 months). All patients were previously discussed with local interventional neuroradiologist considering them not favorable to endovascular therapy. Mini pterional craniotomy with extradural clinoidectomy and internal cervical carotid artery exposure was performed in all of them. 4 patients presented with subarachnoid hemorrhage and required urgent brain surgery. Direct clipping was optimal in 6 aneurysm and 1 was treated with trapping. 4 patients had no neurological deteriotation with excellent outcome and 1 patient died because of hypoperfusion secondary to the supraclinoid carotid trapping. Interdisciplinary management, preoperative planning and neuroanatomy knowledge are emphasized in order to treat this pathology.

Internal Carotid Artery Reconstruction Using Multiple Fenestrated Clips for Complete Occlusion of Large Paraclinoid Aneurysms

OBJECTIVE: Although surgical techniques for clipping paraclinoid aneurysms have evolved significantly in recent times, direct microsurgical clipping of large and giant paraclinoid aneurysms remains a formidable surgical challenge. We review here our surgical experiences in direct surgical clipping of large and giant paraclinoid aneurysms, especially in dealing with anterior clinoidectomy, distal dural ring resection, optic canal unroofing, clipping techniques, and surgical complications. METHODS: Between September 2001 and February 2012, we directly obliterated ten large and giant paraclinoid aneurysms. In all cases, tailored orbito-zygomatic craniotomies with extradural and/or intradural clinoidectomy were performed. The efficacy of surgical clipping was evaluated with postoperative digital subtraction angiography and computed tomographic angiography. RESULTS: Of the ten cases reported, five each were of ruptured and unruptured aneurysms. Five aneurysms occurred in the carotid cave, two in the superior hypophyseal artery, two in the intracavernous, and one in the posterior wall. The mean diameter of the aneurysms sac was 18.8 mm in the greatest dimension. All large and giant paraclinoid aneurysms were obliterated with direct neck clipping without bypass. With the exception of the one intracavenous aneurysm, all large and giant paraclinoid aneurysms were occluded completely. CONCLUSION: The key features of successful surgical clipping of large and giant paraclinoid aneurysms include enhancing exposure of proximal neck of aneurysms, establishing proximal control, and completely obliterating aneurysms with minimal manipulation of the optic nerve. Our results suggest that internal carotid artery reconstruction using multiple fenestrated clips without bypass may potentially achieve complete occlusion of large paraclinoid aneurysms.

Measurement of Critical Structures around Paraclinoidal Area : A Cadaveric Morphometric Study

OBJECTIVE: Although removal of the anterior clinoid process (ACP) is essential surgical technique, studies about quantitative measurements of the space broadening by the anterior clinoidectomy are rare. The purposes of this study are to investigate the dimension of the ACP, to quantify the improved exposure of the parasellar space after extradural anterior clinoidectomy and to measure the correlation of each structure around the paraclinoidal area. METHODS: Eleven formalin-fixed Korean adult cadaveric heads were used and frontotemporal craniotomies were done bilaterally. The length of C6 segment of the internal carotid artery on its lateral and medial side and optic nerve length were checked before and after anterior clinoidectomy. The basal width and height of the ACP were measured. The relationships among the paraclinoidal structures were assessed. The origin and projection of the ophthalmic artery (OA) were investigated. RESULTS: The mean values of intradural basal width and height of the ACP were 10.82 mm and 7.61 mm respectively. The mean length of the C6 lateral and medial side increased 49%. The mean length of optic nerve increased 97%. At the parasellar area, the lengths from the optic strut to the falciform liament, distal dural ring, origin of OA were 6.69 mm, 9.36 mm and 5.99 mm, respectively. The distance between CN III and IV was 11.06 mm. CONCLUSION: With the removal of ACP, exposure of the C6 segments and optic nerve can expand 49% and 97%, respectively. This technique should be among a surgeon's essential skills for treating lesions around the parasellar area.

The Pterional Approach and Extradural Anterior Clinoidectomy to Clip Paraclinoid Aneurysms

OBJECTIVE: The surgical clipping of paraclinoid segment internal carotid artery aneurysms is considered difficult because of the complex anatomical location and important neighboring structures. Our experiences of pterional craniotomy and extradural anterior clinoidectomy (EAC) to clip paraclinoid aneurysms are reported herein. METHODS: We present two patients with paraclinoid aneurysms who underwent surgical clipping using pterional craniotomy and EAC. The clinical results and operative techniques were reviewed from the patients' medical records. RESULTS: EAC improves the surgical field in the suprasellar and periclinoid regions. Clinically, a good outcome was obtained in both cases. No surgical complications directly resulting from the EAC were observed. CONCLUSION: Favorable surgical results can be obtained with pterional craniotomy and EAC for the clipping of paraclinoid aneurysms. EAC is advocated for the clipping of paraclinoid aneurysms.

Meningeal Layers Around Anterior Clinoid Process as a Delicate Area in Extradural Anterior Clinoidectomy : Anatomical and Clinical Study

OBJECTIVE: Removal of the anterior clinoid process (ACP) is an essential process in the surgery of giant or complex aneurysms located near the proximal internal carotid artery or the distal basilar artery. An extradural clinoidectomy must be performed within the limits of the meningeal layers surrounding the ACP to prevent morbid complications. To identify the safest method of extradural exposure of the ACP, anatomical studies were done on cadaver heads. METHODS: Anatomical dissections for extradural exposure of the ACP were performed on both sides of seven cadavers. Before dividing the frontotemporal dural fold (FTDF), we measured its length from the superomedial apex attached to the periorbita to the posterolateral apex which connects to the anterosuperior end of the cavernous sinus. RESULTS: The average length of the FTDF on cadaver dissections was 7 mm on the right side and 7.14 mm on the left side. Cranial nerves were usually exposed when cutting FTDF more than 7 mm of the FTDF. CONCLUSION: The most delicate area in an extradural anterior clinoidectomy is the junction of the FTDF and the anterior triangular apex of the cavernous sinus. The FTDF must be cut from the anterior side of the triangle at the periorbital side rather than from the dural side. The length of the FTDF incision must not exceed 7 mm to avoid cranial nerve injury.

The Avoidance of Microsurgical Complications in the Extradural Anterior Clinoidectomy to Paraclinoid Aneurysms

OBJECTIVE: Paraclinoid segment internal carotid artery (ICA) aneurysms have historically been a technical challenge for neurovascular surgeons. The development of microsurgical approach, advances in surgical techniques, and endovascular procedures have improved the outcome for paraclinoid aneurysms. However, many authors have reported high complication rates from microsurgical treatments. Therefore, the present study reviews the microsurgical complications of the extradural anterior clinoidectomy for treating paraclinoid aneurysms and investigates the prevention and management of observed complications. METHODS: Between January 2004 and April 2008, 22 patients with 24 paraclinoid aneurysms underwent microsurgical direct clipping by a cerebrovascular team at a regional neurosurgical center. Microsurgery was performed via an ipsilateral pterional approach with extradural anterior clinoidectomy. We retrospectively reviewed patients' medical charts, office records, radiographic studies, and operative records. RESULTS: In our series, the clinical outcomes after an ipsilateral pterional approach with extradural anterior clinoidectomy for paraclinoid aneurysms were excellent or good (Glasgows Outcome Scale : GOS 5 or 4) in 87.5% of cases. The microsurgical complications related directly to the extradural anterior clinoidectomy included transient cranial nerve palsy (6), cerebrospinal fluid leak (1), worsened change in vision (1), unplanned ICA occlusion (1), and epidural hematoma (1). Only one of the complications resulted in permanent morbidity (4.2%), and none resulted in death. CONCLUSION: Although surgical complications are still reported to occur more frequently for the treatment of paraclinoid aneurysms, the permanent morbidity and mortality resulting from a extradural anterior clinoidectomy in our series were lower than previously reported. Precise anatomical knowledge combined with several microsurgical tactics can help to achieve good outcomes with minimal complications.

Upper Basilar Artery Aneurysm Surgery via Transclinoidal Approach

OBJECTIVE: The authors present the results of management outcomes for upper basilar artery aneurysms via transclinoidal approach. METHODS: Clinical and angiographic evaluations were performed in twenty two consecutive patients with upper basilar artery aneurysms(three of them had superior cerebellar artery aneurysms) treated by surgery via transclinoidal approach between January, 1990 and April, 2000. RESULTS: Of the 22 patients, fifteen patients had multiple aneurysms including basilar bifurcation aneurysms and basilar-superior cerebellar aneurysms. Seventy seven percent were in good preoperative neurological status(H-H grade I-III), 23% were in poor grade(H-H grade IV). The management outcome was:Glasgow outcome scale(GOS) I 54.5%, GOS II 18%, GOS III 13.6%, GOS IV 4.5% and GOS V(death) 9%. The major causes of morbidity were direct brain damage, perforator occlusion, vasospasm and meningitis. CONCLUSION: The management outcome of upper basilar artery aneurysms treated via clinoidectomy was good(72.5%). Transclinoidal approach is an acceptable alternative for upper basilar artery aneurysms.

Pre -vs. Post-Anterior Clinoidectomy Measurements of the Optic Nerve, Internal Carotid Artery, and Optico-Carotid Triangle: A Cadaveric Morphometric Study

Anterior clinoid process is a small bony structure but it is very important regarding its location and relationships with neighboring neurovascular, dural, and bony structures. Removal of this process has been used in various modification of standard pterional approach. The authors have speculated how much expansion of operative window could be obtained with anterior clinoidectomy, so we measured the lengths of optic nerve, internal carotid artery, and the length and width of optico-carotid triangle(OCT) before and after extradural anterior clinoidectomy 17 times in 10 cadaveric heads. This procedure provided about two fold increase in the length of optic nerve and OCT, and over three fold expansion in the width of OCT. The results indicate that the addition of this relatively simple and easy procedure to standard approach makes the operative field more comfortable and safe than expected. We believe this procedure can be used routinely with or without combination of wide skull base exposure in cases of such lesions as belows: 1) lesions causing optic nerve or chiasmatic compression, 2) lesions encircling/covering the optic nerve and internal carotid artery, 3) lesions arising from or extending into the optic canal, orbital apex, and paraclinoid region, 4) suprasellar/parasellar lesions with limited operative windows(e.g. prefixed chiasm, infra-optic or subchiasmatic locations or adherence).