Surgical Simulation of Extradural Anterior Clinoidectomy through the Trans-superior Orbital Fissure Approach Using a Dissectable Three-dimensional Skull Base Model with Artificial Cavernous Sinus

Endoscopic transorbital extradural anterior clinoidectomy: A stepwise surgical technique and case series study [SevEN-013]

Background

Anterior clinoidectomy is an important procedure for approaching the central skull base lesions. However, anterior clinoidectomy through the endoscopic transorbital approach (ETOA) still has limitations due to technical difficulties and the structural complexity of the anterior clinoid process (ACP). Therefore, the authors designed a stepwise surgical technique of extradural anterior clinoidectomy through the ETOA. The purpose of this study was to evaluate the feasibility of this technique.

Methods

Anatomical dissections were performed in 6 cadaveric specimens using a neuroendoscope and neuro-navigation system. The extradural anterior clinoidectomy through the ETOA was performed stepwise, and based on the results, this surgical technique was performed in the 7 clinical cases to evaluate its safety and efficiency.

Results

Endoscopic extradural anterior clinoidectomy was successfully performed in all cadaveric specimens and patients using the proposed technique. This 5-step technique enabled detachment of the lesser wing of sphenoid bone from the ACP, safe unroofing of the optic canal, and resection of the optic strut without injuring the optic nerve and internal carotid artery. Since the sequential resection of the 3 supporting roots of the ACP was accomplished safely, anterior clinoidectomy was then successfully performed in all clinical cases. Furthermore, no complications related to the anterior clinoidectomy occurred in any clinical case.

Conclusion

We designed a stepwise surgical technique that allows safe and efficient anterior clinoidectomy through the ETOA. Using this technique, extradural anterior clinoidectomy can be accomplished under direct endoscopic visualization with low morbidity. Since this technique is applicable to the central skull base surgery where anterior clinoidectomy is necessary, it expands the application of the ETOA.

Modified extradural temporopolar approach with suction decompression for clipping of large paraclinoid aneurysm: Technical note

Background:

Surgical clipping of complicated large paraclinoid aneurysms are still challenging because strong adhesion of aneurysm itself may hinder the dissection of the perforators and the surrounding anatomical structures from the aneurysm dome.

Methods:

We describe 13 consecutive patients and the clipping of complicated, large-sized paraclinoid aneurysms using a modified extradural temporopolar approach combined with retrograde suction decompression and discuss its advantages and pitfalls.

Results:

Modified extradural temporopolar approach with suction decompression (SD) assistance was performed in all patients. There was no complication related to the surgical procedure. Postoperative outcome was good recovery in 7 patients, moderate disability in 4, and severe disability in 2 caused by severe subarachnoid hemorrhage. Favorable outcomes were achieved in 10 patients (84.6%).

Conclusion:

We recommend its less invasive, safe, and useful combined technique in the treatment of symptomatic paraclinoid aneurysms, which carry the risk of neurovascular injury caused by dissection from the aneurysm dome.

Effect of Fibrin Glue Injection Into the Cavernous Sinus for Hemostasis During Transcavernous Surgery on the Cerebral Venous Draining System

BACKGROUND: The extradural temporopolar transcavernous approach can be used to treat central skull base pathologies, but control of bleeding from the opened cavernous sinus is essential. Oxidized cellulose cotton packing and fibrin glue injection can be used, but the effect on the postoperative venous draining pattern remains unclear.

OBJECTIVE: To investigate changes in the venous drainage pattern immediately after transcavernous surgery with and without fibrin glue injection into the bleeding cavernous sinus.

METHODS: A total of 82 patients treated via the transcavernous approach were retrospectively divided into 2 groups based on the hemostasis methods. Both pre- and postoperative angiography and/or 3-dimensional computed tomography venography were available for 24 patients in the cotton packing group and 12 patients in the fibrin glue group.

RESULTS: Postoperative change in the venous draining pattern was observed in 5 of the 24 patients in the cotton packing group and in 3 of the 12 patients in the fibrin glue group. One of the 82 patients showed postoperative brain swelling due to obstruction of the sphenoparietal sinus. The volume of injected fibrin glue ranged from 0.5 to 2.5 mL (mean, 1.1 ± 0.5 mL), but none of the patients had brain swelling.

CONCLUSION: Direct fibrin glue injection into the opened cavernous sinus is relatively safe, but a change in the venous draining pattern occurs in 25% of patients. The study indicates the potential danger of the change in the venous draining pattern and recommends limiting the injection volume of fibrin glue in transcavernous surgery to avoid complications related to venous congestion.

3D printing from MRI Data: Harnessing strengths and minimizing weaknesses

3D printing facilitates the creation of accurate physical models of patient-specific anatomy from medical imaging datasets. While the majority of models to date are created from computed tomography (CT) data, there is increasing interest in creating models from other datasets, such as ultrasound and magnetic resonance imaging (MRI). MRI, in particular, holds great potential for 3D printing, given its excellent tissue characterization and lack of ionizing radiation. There are, however, challenges to 3D printing from MRI data as well. Here we review the basics of 3D printing, explore the current strengths and weaknesses of printing from MRI data as they pertain to model accuracy, and discuss considerations in the design of MRI sequences for 3D printing. Finally, we explore the future of 3D printing and MRI, including creative applications and new materials.

LEVEL OF EVIDENCE

5 J. Magn. Reson. Imaging 2017;45:635-645.

Operative surgical nuances of modified extradural temporopolar approach with mini-peeling of dura propria based on cadaveric anatomical study of lateral cavernous structures

Background:

Extradural temporopolar approach (ETA) has been modified as less invasive manner and named as trans-superior orbital fissure (SOF) approach with mini-peeling technique. The present study discusses the operative nuances of this modified technique on the basis of cadaveric study of lateral cavernous structures.

Methods:

In five consecutive cadaveric specimens, we performed an extradural anterior clinoidectomy with mini-peeling of the dura propria to expose the anterior clinoid process entirely. We also investigated the histological characteristics of the lateral cavernous sinus (CS) between the dura propria and periosteal dura at the SOF, foramen rotundum (FR), and foramen ovale (FO) levels, and of each trigeminal nerve division.

Results:

Coronal histological examination of the lateral wall of the CS showed invagination of the dura propria and periosteal dura into the SOF. In contrast, no such invagination was observed at the levels of the FR and FO. This finding supports the technical rationale of the only skeletonization of the SOF for peeling of the dura propria but not FR. In addition, our modified ETA method needs only minimal dural incision between the SOF and FR where no cranial nerves are present.

Conclusion:

Our technical modification of ETA may be recommended for surgical treatment of paraclinoid lesions to reduce the risk of intraoperative neurovascular injury.

Usefulness of Extradural Optic Nerve Decompression via Trans-Superior Orbital Fissure Approach for Treatment of Traumatic Optic Nerve Injury: Surgical Procedures and Techniques from Experience with 8 Consecutive Patients

OBJECTIVE

To describe our experience of extradural optic nerve decompression via the trans-superior orbital fissure approach for traumatic optic neuropathy (TON) and retrospectively analyze its advantages and pitfalls.

METHODS

Between September 2009 and August 2014, 8 consecutive patients with TON underwent extradural optic canal decompression via the trans-superior orbital fissure approach. We retrospectively reviewed medical charts, radiologic findings, surgical techniques, complications, and final surgical results.

RESULTS

All 8 patients presented with visual disturbance caused by head injury; 2 patients had no light perception, 6 had light perception, and 2 had ophthalmoplegia. All patients underwent extradural optic canal decompression and high-dose steroid administration within 24 hours after injury. Postoperative visual acuity on discharge was improved in 6 patients and unchanged in 2. The 2 patients with ophthalmoplegia gradually recovered by 3 months after operation. The postoperative outcome was good recovery in 7 patients and moderate disability in 1 patient. There were no complications related to the surgical procedure.

CONCLUSIONS

Emergent optic canal release has been recommended in patients with TON. The advantage of the extradural optic canal decompression via the trans-superior orbital fissure approach is easy identification of the optic canal after partial removal of the anterior clinoid process, resulting in fewer surgical complications. In addition, this procedure can achieve intraorbital decompression if necessary. We recommend this modified approach with mini-peeling as a safe and reliable procedure in patients with TON.

Anatomic Study of Posterior Communicating Artery in Computed Tomographic Image

PURPOSE

This study aims to provide an anatomic data of posterior communicating artery (PComA) and its anatomic relationship to the adjacent structures, so as to guide surgeons in the surgery of internal carotid artery-posterior communicating artery aneurysm clipping and sellar tumors resection without injuring the PComA.

METHODS

Computer topographic angiography images of 123 individuals were reviewed, and the measurements were done on coronal, sagittal, axial, and other user-defined planes after multiplanar reconstruction. Posterior communicating artery was classified in the reconstructed three-dimensional image, measured in proper planes, and located by the structures such as anterior clinoid process (ACP), posterior clinoid process (PCP), and sagittal midline.

RESULTS

Six types of PComA were identified in this study based on its existence and origin. The initial part of PComA can be located by ACP, PCP, and sagittal midline based on some particular angles and distances.

CONCLUSIONS

Posterior communicating artery varies in different individuals, and the radiologic study of it is an optimal way to analyze the variances. The anatomic relations between PComA and basic skull structures such as the ACP and PCP are especially important for neurosurgeons.

Transarterial N-Butyl-2-cyanoacrylate Embolization of an Intraosseous Dural Arteriovenous Fistula Associated With Acute Epidural Hematoma: Technical Case Report

BACKGROUND AND IMPORTANCE

Intraosseous dural arteriovenous fistulae (DAVF) are rare, especially those with drainage into the diploic venous system. The clinical presentation depends on the location of the lesion. This is the first report of an intraosseous DAVF associated with acute epidural hematoma.

CLINICAL PRESENTATION

A 25-year-old man presented with headache and nausea. Imaging of the brain revealed abnormal signals indicative of acute epidural hematoma in the right frontal convexity. Angiography demonstrated a DAVF in the region of the frontal bone. Right external carotid artery angiography showed that the DAVF was fed mainly by the right middle meningeal artery with drainage into diploic veins. Immediately after embolization of the middle meningeal and the distal internal maxillary artery with 17% N-butyl-2-cyanoacrylate, the shunt was completely occluded. The patient was discharged 4 days later without clinical complications.

CONCLUSION

Intraosseous DAVF can be treated by surgical resection or endovascular embolization. Curative treatment requires careful inspection of the angiographic architecture and microsurgical anatomy.

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.