Extradural temporopolar approach to lesions of the upper basilar artery and infrachiasmatic region

Posterior clinoid process in children: morphometric analysis, pneumatization ratio, and surgical implications

PURPOSE

To describe pneumatization and topographic position of the posterior clinoid process (PCP) in healthy children when approaching the anterior and middle fossae.

METHODS

The study consisted of computed tomography images of 180 pediatric patients (90 males / 90 females), aged 1-18 years. The presence or absence of PCP pneumatization was noted, and the distances of certain landmarks to PCP were measured.

RESULTS

The distances of the foramen ovale, foramen rotundum, superior orbital fissure, anterior clinoid process (ACP), foramen magnum and crista galli to PCP were measured as 18.59 ± 3.36 mm, 15.37 ± 3.45 mm, 14.60 ± 3.05 mm, 5.27 ± 3.24 mm, 32.03 ± 3.27 mm, and 30.45 ± 3.93 mm, respectively. These parameters increased with growth (between 1-18 years), but the distance between PCP and ACP decreased with an irregular pattern. In 11 sides (3.10%), a fusion between PCP and ACP was determined. PCP pneumatization was identified in 32 sides (8.9%). Its pneumatization correlated with pediatric ages (p < 0.001), but not gender (p = 0.459) or side (p = 0.711). Most of PCP pneumatization appeared after late childhood period (i.e., between 10-18 years).

CONCLUSION

Our study provides beneficial data for neurosurgeons to use PCP as a reference point for creating a skull base map in children, because of the incomparable position of PCP in the skull base center.

Growth Dynamic of the Dorsum Sellae in Fetuses

OBJECTIVE

To determine the dimension of the dorsum sellae (DS) in fetuses.

METHODS

Skull bases of 32 fetuses aged from 17 to 32 weeks were included in the work. The length of the DS at its superior border (DSL-SB) and the thickness of DS at its middle part (DST-ML) were measured. In addition, DS's height at its right lateral margin (DSH-RLB), at its left lateral margin (DSH-LLB), and at its middle part (DSH-ML) were measured.

RESULTS

DSL-SB, DSH-RLB, DSH-LLB, DSH-ML, and DST-ML were measured as 8.42±1.89, 2.67±0.68, 2.73±0.68, 2.48±0.75, and 2.00±0.50 mm, respectively. All parameters were statistically similar for both sexes ( P >0.05). All parameters increased with advancing gestational weeks ( P <0.001). Linear functions were calculated for DSL-SB (y=- 1.756 + 0.426 × age), DSH-RLB (y=- 1.072 + 0.156 × age), DSH-LLB (y=- 0.851 + 0.150 × age), DSH-ML (y=- 1.687 + 0.174 × age), and DST-ML (y=- 0.473 + 0.103 × age).

CONCLUSION

In fetuses, DS size grows with age. The linear functions regarding DS-related parameters may be used to estimate its size.

Zygomatic Anterolateral Temporal Approach for P1/P2 segment complex posterior cerebral aneurysm: a single-center retrospective study

Treating complex posterior cerebral artery (PCA) aneurysms, such as fusiform, giant, and dissecting aneurysms, poses significant challenges. Parent artery occlusion carries a risk of ischemic stroke and fails to alleviate mass effects. This study aims to analyze the technical nuances and patient outcomes of treating complex PCA aneurysms, ranging from the P1 to P2P segments, using a Zygomatic Anterolateral Temporal Approach(ZATA) combined with flow reconstruction. This study was a retrospective study. Surgical treatment was performed on twelve patients with complex PCA aneurysms located in the P1 to P2P segments. Ten patients underwent flow reconstruction including Superficial Temporal Artery(STA)-Middle Cerebral Artery(MCA),Internal Maxillary Artery(IMA)-Radial Artery(RA)-MCA,STA-PCA(P2), and IMA-RA-PCA(P2). The aneurysm occlusion rate, surgical complications, and patient prognosis, including stroke occurrence/ modified Rankin Scale(mRS), were recorded and analyzed. Using the ZATA, all twelve complex PCA aneurysms were successfully clipped/resected/trapped. This included two high-position aneurysms (> 3 mm above the posterior clinoid process) at the P1/P2 junction and three P2P aneurysms. The mass effects of six large or giant aneurysms were resolved or alleviated. Postoperative and follow-up CTA/DSA confirmed the patency of the bypass vessels. Four patients experienced strokes in the perioperative period, with three ischemic and one hemorrhagic. The median follow-up period was 28.5 months. At the last follow-up, the good prognosis rate (mRS ≤ 2) was 83.3%, and one patient had died. Clipping/resection/trapping of aneurysms via the ZATA, combined with flow reconstruction, is a feasible option for treating complex PCA aneurysms from the P1 to P2P segments. This approach helps maintain or improve cerebral perfusion in the affected vascular territory.

Pneumatization types of the dorsum sellae: a computed tomography study

PURPOSE

The present work aimed to classify the pneumatization of the dorsum sellae (DS) in subjects aged 1-90 years.

METHODS

The study consisted of computed tomography images of 1080 subjects (582 males / 498 females), aged 1-90 years (mean age: 45.51 ± 26.06 years). Four different types regarding DS pneumatization were defined as follows: Type 0: no pneumatization, Type 1: pneumatization < 50%, Type 2: pneumatization > 50%, and Type 3: total pneumatization.

RESULTS

DS pneumatization was identified in 354 (32.8%) subjects (189 males and 165 females). Its pneumatization was identified in 51 (21.2%) out of 241 children, and 303 (36.1%) out of 839 adults. The frequency of DS pneumatization types was found as follows: Type 0 (no pneumatization in 726 subjects, 67.2%) > Type 1 (pneumatization < 50% in 234 subjects, 21.6%) > Type 2 (pneumatization > 50% in 87 subjects, 8.1%) > Type 3 (total pneumatization in 33 subjects, 3.1%). DS pneumatization incidence was affected by ages (p < 0.001), but not sex (p = 0.818). The pneumatization degrees of DS (i.e., the distributions of Types 1-3) were not affected by ages (p = 0.637) or sex (p = 0.391).

CONCLUSION

The pneumatization incidence of DS increased significantly with advancing adult ages (especially in elderly people). DS pneumatization should be taken into account by neurosurgeons and neuroradiologists to decrease the risk of complications such as cerebrospinal fluid fistula during surgeries such as posterior clinoidectomy.

Operative management of trigeminal schwannomas: based on a modified classification in a study of 93 cases

BACKGROUND

Advances in microscopic and endoscopic surgical techniques have outpaced traditional classification and transcranial surgical strategies, especially with reference to the treatment of trigeminal schwannomas (TSs). A modified TS classification is proposed and appropriate surgical strategies are discussed.

METHODS

The cases of 93 patients who underwent surgical treatment in Beijing Tiantan Hospital in the previous 6 years were analyzed retrospectively, and a literature review was conducted.

RESULTS

Classification is based on surgical direction. Tumors were classified as follows: type A, backward orientation, located in the orbit or orbit and middle cranial fossa (8 cases, 8.6%); type B, upward orientation, located in the pterygopalatine fossa, infratemporal fossa or pterygopalatine fossa, infratemporal fossa, and middle cranial fossa (23 cases, 24.7%); type C, forward and backward orientations, located in the middle cranial fossa, posterior cranial fossa or both (58 cases, 62.4%); and type D, located in multiple regions (4 cases, 4.3%). 91.40% of patients underwent gross total resection (GTR) with 29 cases receiving endoscopic resection of whom 93.10% (27/29) experienced GTR.

CONCLUSION

The 93 cases were satisfactorily divided into four types, according to tumor location and surgical orientation, enabling safe and effective removal by appropriate surgery.

The Extended-Sphenoid Ridge Approach: A New Technique for the Surgical Treatment of Skull Base Tumors in Pediatric Patients

The sphenoid ridge approach (SRA) was initially described as a surgical technique for treating vascular pathologies near the Sylvian fissure. However, limited studies have systematically explored the use of skull base techniques in pediatric patients. This study investigated an extended variation in the sphenoid ridge approach (E-SRA), which systematically removed the pterion, orbital walls (roof and lateral wall), greater sphenoid wing, and anterior clinoid process to access the base of the skull.

OBJECTIVE

This report aimed to evaluate the advantages of the extradural removal of the orbital roof, pterion, sphenoid wing, and anterior clinoid process as a complement to the sphenoid ridge approach in pediatric patients.

PATIENTS AND METHODS

We enrolled 36 patients with suspected neoplastic diseases in different regions. The E-SRA was performed to treat the patients. Patients were included based on the a priori objective of a biopsy or a total gross resection. The surgical time required to complete the approach, associated bleeding, and any complications were documented.

RESULTS

Our results demonstrated that the proposed a priori surgical goal, biopsy, or resection were successfully achieved in all cases. In addition, using the E-SRA technique was associated with a shorter operative time, minimal bleeding, and a lower incidence of complications. The most frequently encountered complications were related to dural closure.

CONCLUSIONS

The extended sphenoid ridge approach represents a safe and effective option for managing intracranial tumors in pediatrics.

Epidural Pretemporal Transcavernous Approach Double-Barrel Superficial Temporal Artery-Posterior Cerebral Artery/Superior Cerebellar Artery Bypass for a Ruptured Anterior Spinal Artery Aneurysm

BACKGROUND

Rostral posterior circulation bypass is technically challenging. Pretemporal approach has been reported to facilitate the bypass procedure within the oculomotor-tentorial triangle. However, bridging veins converging into cavernous sinus at the temporal pole usually need to be sacrificed.

OBJECTIVE

To report operative nuances of rostral posterior circulation bypass with an emphasis on preserving the Sylvian veins and enlarging surgical space, we use a double-barrel superficial temporal artery-posterior cerebral artery/superior cerebellar artery anastomosis using an epidural pretemporal transcavernous approach.

METHODS

A 54-year-old man had a subarachnoid hemorrhage attack 1 month before the admission. A flow-related anterior spinal artery aneurysm with bilateral vertebral artery occlusive diseases was indicated. The aneurysm was difficult to be directly treated, either by the endovascular approach or by the microsurgical clipping. A double-barrel superficial temporal artery-superior cerebellar artery/posterior cerebral artery bypass was performed using an epidural pretemporal transcavernous approach.

RESULTS

The anastomoses were successfully accomplished in a large surgical space. The patient recovered well with no events, except a transient right cranial nerve III paralysis. The aneurysm was demonstrated to be completely regressed at the 5-month follow-up.

CONCLUSION

An epidural pretemporal transcavernous approach could be an alternative for rostral posterior circulation bypass.

Microsurgical Approach for True Posterior Communicating Artery Aneurysms: Literature Review and Illustrative Case

True posterior communicating artery (PCoA) aneurysms are rare. Although true PCoA aneurysms have been reported to be located close to the internal carotid artery, at the middle part of PCoA, or close to the posterior cerebral artery; the best surgical approach to treat true PCoA aneurysms in each location remains unclear. We conducted a literature review using data from PubMed. Data on demographics, location, and projecting direction of the aneurysm, surgical approach, and surgical complications were collected. A total of 47 true PCoA aneurysms were included. Twenty-nine aneurysms originated from the proximal portion, 10 from the middle portion, and 6 from the distal portion; there were two giant aneurysms. The ipsilateral pterional approach was used for 37 true PCoA aneurysms (27 in proximal portion, 8 in middle portion, and 2 in distal portion of PCoA). The anterior temporal approach was used for two distal-portion aneurysms and one giant aneurysm. The anterior subtemporal approach was used for one distal-portion aneurysm. The subtemporal approach was used for two middle-portion aneurysms and one giant aneurysm. The contralateral pterional approach was used for two proximal-portion and one distal-portion aneurysms. Although most true PCoA aneurysms can be treated by the pterional approach, other means such as anterior temporal and subtemporal approaches can be applicable for aneurysms in the middle and distal portions of the PCoA or giant aneurysms. Surgeons should select an appropriate approach for each aneurysm while considering the advantages and disadvantages of each technique.

Histology of the Porous Oculomotorius: Relevance to Anterior Skull Base Approaches

Objective: Mobilization of cranial nerve III (CNIII) at its dural entry site is commonly described to avoid damage from stretching during approaches to the parasellar, infrachiasmatic, posterior clinoid, and cavernous sinus regions. The histologic relationships of CNIII as it traverses the dura, and the associated surgical implications are nonetheless poorly described. We herein assess the histology of the CNIII-dura interface as it relates to surgical mobilization of the nerve. Methods: A fronto-orbitozygomatic temporopolar approach was performed on six adult cadaveric specimens. The CNIII-dural entry site was resected and histologically processed. The nerve-tissue planes were assessed by a neuropathologist. Results: Histologic analysis demonstrated that CNIII remained separate from the dura within the oculomotor cistern (porous oculomotorius up to the oculomotor foramen). Fusion of the epineurium of CNIII and the connective tissue of the dura was seen at the level of the foramen, with no clear histologic plane identified between these structures. Conclusion: CNIII may be directly mobilized within the oculomotor cistern, while dissections of CNIII distal to the oculomotor foramen should maintain a thin layer of connective tissue on the nerve.

Case Report: Internal Carotid Artery Thrombosis: A Rare Complication After Fibrin Glue Injection for Cavernous Sinus Hemostasis

Background: Fibrin glue injection within the cavernous sinus (CS) is a demonstrably safe and simple technique to control venous bleeding with a low complication rate. However, this technique does have inherent risks. We illustrate 2 cases of internal carotid artery (ICA) thrombosis after fibrin glue injection in the CS for hemostasis.

Methods: After encountering this complication recently, we conducted a retrospective review of the surgical database of 2 senior neurosurgeons who specialize in cerebrovascular and skull base surgery to identify patients with any complications associated with the use of fibrin glue injection for hemostasis. Approval was given by respective institutional review boards, and patient consent was obtained.

Results: Of more than 10,000 microsurgery procedures performed by 2 senior neurosurgeons with a combined experience of 40 years, including procedures for aneurysms and skull base tumors, 2 cases were identified involving ICA thrombosis after fibrin glue injection in the CS for hemostasis. Both cases involved severe ischemic complications as a result of the ICA thrombosis. In this article, we present their clinical presentation, characteristics, management, and outcomes.

Conclusion: Direct injection of fibrin glue into the CS for hemostasis can effectively control venous bleeding and facilitate complex dissections. However, it can be associated with ICA thrombosis, with subsequent serious ischemia and poor prognosis. Although this complication appears to be rare, increased awareness of this problem should temper the routine use of fibrin glue in anterior clinoidectomy and transcavernous approaches.

Extradural anterior clinoidectomy in surgical management of clinoidal meningiomas

Background

Despite the recent advances in skull base surgery, microsurgical techniques, and neuroimaging, yet surgical resection of clinoidal meningiomas is still a major challenge. In this study, we present our institution experience in the surgical treatment of anterior clinoidal meningiomas highlighting the role of extradural anterior clinoidectomy in improving the visual outcome and the extent of tumor resection. This is a prospective observational study conducted on 33 consecutive patients with clinoidal meningiomas. The surgical approach utilized consisted of extradural anterior clinoidectomy, optic canal deroofing with falciform ligament opening in all patients. The primary outcome assessment was visual improvement and secondary outcomes were extent of tumor resection, recurrence, and postoperative complications.

Results

The study included 5 males and 28 females with mean age 49.48 ± 11.41 years. Preoperative visual deficit was present in 30 (90.9%) patients. Optic canal involvement was present in 24 (72.7%) patients, ICA encasement was in 16 (48.5%), and cavernous sinus invasion in 8 (24.2%). Vision improved in 21 patients (70%), while 6 patients (20%) had stationary course and 1 patient (3%) suffered postoperative new visual deterioration. Gross total resection was achieved in 24 patients (72.7%). The main factors precluding total removal were cavernous sinus involvement and ICA encasement. Mortality rate was 6.1%; mean follow-up period was 27 ± 13 months.

Conclusions

In this series, the use of extradural anterior clinoidectomy provided a favorable visual outcome and improved the extent of resection in clinoidal meningioma patients.

Decompression of Cavernous Sinus for Trigeminal Neuropathic Pain From Perineural Spread of Tumor: 2-Dimensional Operative Video

Head and neck malignancies with perineural spread are rare. Patients can present with neuropathic pain and cranial nerve palsies.1 Skull base approaches for surgical decompression are a consideration for patients to provide symptom relief.2 We demonstrate a frontotemporal extradural approach for a patient with worsening visual symptoms and refractory neuropathic pain in the V1, V2, and V3 distributions and briefly review the relevant anatomy.3-7  A 41-yr-old female with a poorly differentiated carcinoma of the head and neck with an infiltration of the cavernous sinus and perineural spread along the trigeminal nerve presented with severe neuropathic facial pain and anesthesia. She had previously undergone radiosurgery. Magnetic resonance imaging (MRI) demonstrated an interval increase in perineural disease within the cavernous sinus with extension intradurally. Her pain was medically refractory. A 2-dimensional intraoperative video illustrates the microsurgical decompression of her perineural invasion along the skull base as a palliative procedure. The patient recovered well postoperatively and had a symptomatic improvement in her pain and visual symptoms. Her preoperative facial numbness persisted postoperatively as expected. Postoperative imaging demonstrates a gross total resection of the intradural component of the tumor with decompression and expected expansion of the cavernous sinus. Because of the retrospective nature of this report, informed consent was not required. Images within the video have been reproduced from Fukuda et al4 with permission from © Georg Thieme Verlag KG; and Matsuo et al5 by permission of the Congress of Neurological Surgeons.

Tailored Anterior Clinoidectomy: Beyond the Intradural and Extradural Concepts

Anterior clinoidectomy (AC) is a key microsurgical step for the safe and successful management of parasellar pathologies that involve the anterior clinoid process (ACP) and the optic canal. Traditionally, extra and intradural ACs are performed separately according to the surgeon's experience or preference. The objective is to present and discuss the tailored AC concept through illustrative cases. We conducted a retrospective record review of three patients who underwent AC as a surgical step for the treatment of parasellar pathologies that involve the ACP and optic canal. A review of the relevant literature on AC was performed in the PubMed, LILACS, and SciELO databases.

In all three cases, the pterional craniotomy was the preferred approach for AC. Case 1, a 47-year-old female patient with type III anterior clinoidal meningioma, underwent a tailored intradural technique (optic canal unroofing) with total tumor resection and complete visual recovery. Case 2, a 63-year-old female patient with a complex type II anterior clinoidal meningioma with extensive hyperostosis of the ACP, underwent a hybrid AC technique with complete removal of the tumor and visual improvement. Case 3, a 62-year-old female, underwent a tailored intradural AC for clipping an incidental carotid-ophthalmic aneurysm.

Tailored AC aims to provide adequate exposure with less risk of neurovascular injury, allowing enough space to safely treat parasellar lesions. The type, size, and location of the lesion, as well as the surgeon’s experience, should always be considered for surgical planning.

The side door and front door to the upper retroclival region: a comparative analysis of the open pretemporal and the endoscopic endonasal transcavernous approaches

OBJECTIVE

The pretemporal transcavernous approach (PTA) and the endoscopic endonasal transcavernous approach (EETA) are both used to access the retroclival region. A direct quantitative comparison of both approaches has not been made. The authors compared the technical nuances of, and surgical exposure afforded by, each approach and identified the key elements of the approach selection process.

METHODS

Fourteen cadaveric specimens underwent either PTA (group A) or EETA with unilateral (group B) followed by bilateral (group C) interdural pituitary gland transposition. The percentage of drilled clivus; length of exposed oculomotor nerve (cranial nerve [CN] III), posterior cerebral artery (PCA), and superior cerebellar artery (SCA); and surgical area of exposure of both cerebral peduncles and the pons for the 3 groups were measured and compared.

RESULTS

Group A had a significantly lower percentage of drilled area than group B (mean [SD], 35.6% [11.2%] vs 91.3% [4.9%], p < 0.01). In group C, 100% of the upper third of the clivus was drilled in all specimens. Significantly longer segments of the ipsilateral PCA (p < 0.01) and SCA (p < 0.01) were exposed in group A than in group B. There was no significant difference in the length of the ipsilateral CN III exposed among the 3 groups. There was also no significant difference between group A and either group B or group C for the contralateral CN III or PCA exposure. However, longer segments of the contralateral SCA were exposed in group C than in group A (p = 0.02). Furthermore, longer segments of CN III (p < 0.01), PCA (p < 0.01), and SCA (p < 0.01) were exposed in group C than in group B. For brainstem exposure, there was greater exposure of the pons in group C than in group A (mean [SD], 211.4 [19.5] mm2 vs 157.7 [25.3] mm2, p < 0.01) and group B (211.4 [19.5] mm2 vs 153.9 [34.1] mm2, p < 0.01). However, significantly greater exposure of the ipsilateral peduncle was observed in group A (mean [SD], 125.6 [43.1] mm2) than in groups B and C (56.3 [6.0] mm2, p < 0.01). Group C had significantly greater exposure of the contralateral peduncle than group B (p = 0.02).

CONCLUSIONS

This study is the first to quantitatively identify the advantages and limitations of the PTA and EETA from an anatomical perspective. Understanding these data may help the skull base surgeon design a maximally effective yet minimally invasive approach to individual lesions.

[Transcranial microsurgical decompression of the optic canal in surgical treatment of meningiomas of the sellar region]

RATIONALE

When removing the meningiomas of the sellar region, there is always a risk of visual impairment for various reasons, in particular, as a result of traction damage to the optic nerve. Decompression of the optic canal increases nerve mobility during tumor manipulation. In cases of meningioma growing into the canal, its decompression often seems necessary.

AIM

Evaluation of the effectiveness and risks of performing decompression of the optic canal.

MATERIALS AND METHODS

The study included patients with meningiomas of the parasellar location, who underwent surgical treatment at the Burdenko Neurosurgical Center for the period from 2001 to 2017. They were divided into two groups - main and control. The main group consisted of 129 patients who underwent decompression of the optic nerve canals when the tumor was removed. The tumor matrix in this group was most often located in the region of the tuberum sellae, supradiaphragmally, in the region of the anterior clinoid process and the optic canal. In 31 cases, decompression was bilateral - during one operation and using one access in 27 patients; in 4 cases, the decompression of the second canal was delayed for 1.5-3 months after the first operation. 160 decompressions were performed by the intradural and 7 - by extradural methods. During intradural decompression, the roof of the optic canal was resected, and during extradural decompression, the lateral wall of the canal was trephined. The control group consisted of 308 patients who did not undergo canal decompression when the tumor was removed. It included meningiomas with a predominant location of the matrix in the area of the tuberclum and diaphragm of the sella. Tumors in both groups were removed according to the same principles (matrix coagulation, mainly the gradual removal of the tumor, the use of ultrasonic aspirator, a situational decision on the radicality of the operation, etc.). The main difference between operations in these two groups was only canal related algorithms (with or without its trepanation), as well as the probable prevalence of significant lateral tumor growth in cases with canal trepanation. Visual functions in the «primary» group were evaluated before and after operations with trepanation of the canal depending on various factors - the initial state of vision and the radicality of the tumor excision, including removal from the canal. The differences in the postoperative dynamics of vision in the main and control groups were studied. The primary data processing was carried out using the program MSExcel. Secondary statistical processing was carried out using the program Statistica. To assess the statistical significance of differences in the results obtained in the compared patient groups, the Chi-square test was used, and in the case of small groups - the exact Fisher test was applied.

RESULTS

In the main group postoperative vision improvement of varying degrees on the side of trepanation was registered in 36.9% (59 out of 160) cases, no vision changes were found in 36.9% (59 out of 160), and in 26,2% (42 out of 160) the eyesight deteriorated. If preserving vision is attributed to a satisfactory result, then in general the results of these operations should be considered good. A comparative study of the results of removal of meningiomas with trepanation of the canals (main group) or without it (control group) was carried out among patients with the most critical vision situation (visual acuity 0.1 and below, up to only light perception). These groups are comparable in the number of observations - 62 and 73 respectively. The predominance of cases with improved vision in the main group compared with the control group (50.0% versus 38.36%) and a lower incidence of vision impairment (22.58% versus 34.25%) were found. However, the revealed differences are statistically unreliable and make it possible for us to talk only about the trend. The complications associated with trepanation of the canal include mechanical damage to the nerve by the drill. In our series of observations, there was only 1 case of abrasion of the nerve surface with the burr, which did not lead to a significant visual impairment. With the intradural method of trepanation in the area of the medial wall of the canal, the sphenoid sinus may open (in our series, in 34 cases out of 160 trepanations). Immediately closure of these defects was performed by various auto- and allomaterials in various combinations (pericranium, fascia, muscle fragment, hemostatic materials, and fibrin-thrombin glue). A true complication - CSF rhinorrhea liquorrhea developed in only one case, which required transnasal plastic surgery of the CSF fistula using a mucoperiostal flap.

CONCLUSIONS

1. Trepanation of the optic canal in cases of meningiomas of parasellar localization is a relatively safe procedure in the hands of a trained neurosurgeon and does not worsen the results of operations compared with the excision of the same tumors without trepanation of the canal. 2. The literature data and the results of our study make it possible to consider the decompression of the optic canal as an optional, but in many cases, useful option that facilitates the transcranial removal of some meningiomas of the sellar region.

Anterior Clinoid Metastasis as First Presentation of a Signet Ring Cell Carcinoma: An Intriguing Diagnosis

Background  We report an extremely unusual case of anterior clinoid process (ACP) metastasis as the first presentation of a signet ring cell carcinoma.

Case Description  A 54-year-old female patient presented with right-sided visual disturbances due to optic nerve compression from a computed tomography (CT)-identified right anterior clinoid bone lesion. Contrast-enhanced magnetic resonance imaging showed an extra-axial, well-bordered enhancing mass extending from the right ACP toward the inner lumen of the optic canal. Pterional approach was adopted to remove the lesion and decompress the optic canal. Histological examination demonstrated a metastasis from a signet ring cell carcinoma. Postoperative CT showed near-total resection of the tumor and decompression of the optic canal. Visual defect remained unchanged.

Conclusion  Metastasis should be considered in the differential diagnosis of the ACP lesions. The early suspicion and identification of this extremely rare pathological entity can be helpful for the prompt management of patients, especially in the absence of any other signs of oncological diseases.

Anatomical meningo-orbital band evaluation and clinical implications: a cadaveric dissection study

BACKGROUND

The meningo-orbital band (MOB) is a dural structure which runs around the superior orbital fissure (SOF) tethering the frontotemporal basal dura to the periorbita, through the SOF. MOB division is important to expose and remove the anterior clinoid process, to access to proximal carotid artery and cavernous sinus area. The goal of the study was to measure how the MOB could be safely incised without cranial nerves and cavernous sinus injuries.

METHODS

Anatomical dissections and extradural exposure of the anterior clinoid process was performed on 20 cadavers (40 sides). Measurement of the MOB thickness was performed before its incision, after dura propria dissection, and retraction off the inner cavernous membrane, to expose the cranial nerves.

RESULTS

We analyzed 20 cadaveric formalin-fixed heads injected with colored silicone, 11 man and 9 woman of caucasian race. The average length of a safe incision of the MOB was 10.6 ± 1.1 mm on the right side, and 10.65 ± 1.09 mm on the left side.

CONCLUSIONS

In our study the average length of a safe incision of the MOB was 10.6 ± 1.1 mm. Thus, the incision length of the MOB should not exceed 9 mm; the peeling of the anterior cavernous sinus and of the SOF, dissecting the two layers of the dura throughout the incision of the MOB, is an useful technique to avoid cranial nerves and cavernous sinus lesions.

Assessment of the endoscopic endonasal approach to the basilar apex region for aneurysm clipping

OBJECTIVE

The expanded endoscopic endonasal approach (EEA) has shown promising results in treatment of midline skull base lesions. Several case reports exist on the utilization of the EEA for treatment of aneurysms. However, a comparison of this approach with the classic transcranial orbitozygomatic approach to the basilar apex (BAX) region is missing.The present study summarizes the results of a series of cadaveric surgical simulations for assessment of the EEA to the BAX region for aneurysm clipping and its comparison with the transcranial orbitozygomatic approach as one of the most common approaches used to treat BAX aneurysms.

METHODS

Fifteen cadaveric specimens underwent bilateral orbitozygomatic craniotomies as well as an EEA (first without a pituitary transposition [PT] and then with a PT) to expose the BAX. The following variables were measured, recorded, and compared between the orbitozygomatic approach and the EEA: 1) number of perforating arteries counted on bilateral posterior cerebral arteries (PCAs); 2) exposure and clipping lengths of the PCAs, superior cerebellar arteries (SCAs), and proximal basilar artery; and 3) surgical area of exposure in the BAX region.

RESULTS

Except for the proximal basilar artery exposure and clipping, the orbitozygomatic approach provided statistically significantly greater values for vascular exposure and control in the BAX region (i.e., exposure and clipping of ipsilateral and contralateral SCAs and PCAs). The EEA with PT was significantly better in exposing and clipping bilateral PCAs compared to EEA without a PT, but not in terms of other measured variables. The surgical area of exposure and PCA perforator counts were not significantly different between the 3 approaches. The EEA provided better exposure and control if the BAX was located ≥ 4 mm inferior to the dorsum sellae.

CONCLUSIONS

For BAX aneurysms located in the retrosellar area, PT is usually required to obtain improved exposure and control for the bilateral PCAs. However, the transcranial approach is generally superior to both endoscopic approaches for accessing the BAX region. Considering the superior exposure of the proximal basilar artery obtained with the EEA, it could be a viable option when surgical treatment is considered for a low-lying BAX or mid-basilar trunk aneurysms (≥ 4 mm inferior to dorsum sellae).

Saccular or dissecting aneurysms involving the basilar trunk: Endovascular treatment and clinical outcome

Objectives: Basilar artery trunk aneurysms (BTAs) are a rare pathology and difficult to treat. We present our experience regarding angiographic results and clinical outcomes for 16 BTAs treated by reconstructive endovascular treatment (EVT) using stent or balloon. Methods: Between January 2003 and December 2014, 15 patients (mean age, 58.6 years; 11 males) with 16 BTAs were enrolled. Clinical manifestation, outcomes and procedural complications were evaluated retrospectively, and follow-up angiography was performed 12 and 24 months after procedure. Results: Subarachnoid hemorrhage (SAH) developed in seven aneurysms and nine were found incidentally. In one case, SAH followed by acute infarction on pons. The location of the aneurysms was the pure basilar artery (BA) trunk in 13 and the junction of the BA and the superior cerebellar artery in 3. Reconstructive EVT was technically successful in 15 aneurysms (93.8%) and failed in one due to the difficulty of vascular access. Stent/balloon-assisted coiling was performed in 13 aneurysms and sole stent therapy in two aneurysms. One patient had periprocedural complication of acute in-stent thrombosis. All treated patients had no symptoms with the usual activities except three patients, who died from myocardial infarction, aneurysmal rebleeding, and cerebellar infarction. Angiographic follow-up was performed in nine aneurysms; three aneurysms were recanalized (33.3%) and six aneurysms had no interval change (66.7%). There was no significant event during the follow-up period (mean, 23.5 months). Conclusion: In the treatment of BTAs, reconstructive EVT may provide a feasible and safe option to microsurgery.

Anterior clinoidectomy using an extradural and intradural 2-step hybrid technique

In Brief: The authors found a practical intraoperative landmark to localize the optic strut during anterior clinoidectomy and used it as the basis for performing anterior clinoidectomy in two steps: extradural phase and intradural phase. This anatomically based technique can increase the safety of anterior clinoidectomy by providing easily identifiable landmarks and reducing intradural bone drilling, which could put the adjacent neurovauscular structures at risk.

Analysis of Surgical Freedom Variation Across the Basilar Artery Bifurcation: Towards a Deeper Insight Into Approach Selection for Basilar Apex Aneurysms

BACKGROUND

The orbitozygomatic approach is generally advocated over the pterional approach for basilar apex aneurysms. However, the impact of the extensions of the pterional approach on the obtained maneuverability over multiple vascular targets (relevant to basilar apex surgery) has not been studied before.

OBJECTIVE

To analyze the patterns of surgical freedom change across the basilar bifurcation between the pterional, orbitopterional, and orbitozygomatic approaches.

METHODS

Surgical freedom was assessed for 3 vascular targets important in basilar apex aneurysm surgery (ipsilateral and contralateral P1-P2 junctions, and basilar apex), and compared between the pterional, orbitopterional, and orbitozygomatic approaches in 10 cadaveric specimens.

RESULTS

Transitioning from the pterional to orbitopterional approach, the surgical freedom increased significantly at all 3 targets (P < .05). However, the gain in surgical freedom declined progressively from the most superficial target (60% for ipsilateral P1-P2 junction) to the deepest target (35% for contralateral P1-P2 junction). Conversely, transitioning from the orbitopterional to the orbitozygomatic approach, the gain in surgical freedom was minimal for the ipsilateral P1-P2 and basilar apex (<4%), but increased dramatically to 19% at the contralateral P1-P2 junction.

CONCLUSION

The orbitopterional approach provides a remarkable increase in surgical maneuverability compared to the pterional approach for the basilar apex target and the relevant adjacent arterial targets. However, compared to the orbitopterional, the orbitozygomatic approach adds little maneuverability except for the deepest target (ie, contralateral P1-P2 junction). Therefore, the orbitozygomatic approach may be most efficacious with larger basilar apex aneurysms limiting the control over of the contralateral P1 PCA.

Surgical Strategies for Ruptured Complex Aneurysms Using Skull Base Technique and Revascularization Surgeries

Object:

Surgical clipping of paraclinoid aneurysm, thrombosed large aneurysm, and/or vertebral-basilar dissecting aneurysms can be very difficult and has relatively high morbidity. We describe our experience using skull base and bypass technique and discuss the advantages and its pitfalls.

Patients and Methods:

We retrospectively reviewed medical charts of 22 consecutive patients with complex aneurysmal lesions underwent skull base and/or bypass techniques between March 2012 and April 2017.

Results:

There were 5 patients with paraclinoid or internal carotid artery (ICA) aneurysm underwent modified extradural temporopolar approach with mini-peeling of the dura propria with suction decompression, 3 patients with ICA aneurysm underwent intradural anterior clinoidectomy, 12 patients with vertebral dissecting aneurysm through transcondylar fossa approach (6 patients underwent occipital artery-posterior inferior cerebellar artery [OA-PICA] bypass), 1 patients with vertebral artery dissection underwent superficial temporal artery-superior cerebellar artery and OA-PICA bypass through posterior transpetrosal approach, 1 patient with arteriovenous fistula at the ventral side of the craniovertebral junction through extremely far lateral approach. Surgical outcome was good recovery in 10 patients, moderate disability in 4, severe disability in 4, vegetative state in 2, and dead is 2 patients. The favorable outcome was 63.6%, and poor outcome was 36.4%, which showed poor grade subarachnoid hemorrhagic patients. No patient suffered any complication related to re-rupture and/or incomplete clipping.

Conclusion:

Skull base technique, which can create a wide and shallow operative space, allowed us to improve surgical outcome and to reduce the risk of intraoperative neurovascular injury for surgical treatment of deeply located complex aneurysms.

Comprehensive Anatomic Assessment of the Pterional, Orbitopterional, and Orbitozygomatic Approaches for Basilar Apex Aneurysm Clipping

BACKGROUND

The pterional approach, along with its orbitopterional and orbitozygomatic extensions, is among the most common surgical approaches for tackling challenging aneurysms of the basilar artery apex (BAX). There is general consensus that the orbitozygomatic approach provides the best exposure for these lesions. However, there is little objective evidence to support approach selection for surgical treatment of BAX aneurysms.

OBJECTIVE

To compare different features regarding surgical treatment of BAX aneurysms between the pterional, orbitopterional, and orbitozygomatic approaches.

METHODS

The pterional, orbitopterional, and orbitozygomatic approaches were sequentially completed on 10 cadaveric specimens. The visibility of perforators, lengths of exposure, and safe clipping for major BAX branches, surgical area of exposure, and the surgical freedom for the BAX target were assessed.

RESULTS

The orbitopterional approach provided significantly greater values than the pterional approach in all variables, except for exposure of the bilateral P1 posterior cerebral artery (PCA) perforators. When compared to the orbitopterional approach, the orbitozygomatic approach did not provide a statistically significant increase in (1) surgical freedom through the carotid-oculomotor triangle, (2) area of exposure, (3) ipsilateral, and (4) contralateral P1 PCA perforator visibility, and (5) ipsilateral PCA exposure and (6) clipping lengths.

CONCLUSION

The orbitopterional approach provides significantly greater surgical exposure to BAX than the pterional approach. The orbitopterional approach is less invasive while providing similar surgical access to the BAX compared to the orbitozygomatic. The results of this study show that the orbitopterional approach may be optimal for the treatment of most BAX aneurysms, particularly to reduce morbidity resulting from the full orbitozygomatic approach.

Less Invasive Modified Extradural Temporopolar Approach for Paraclinoid Lesions: Operative Technique and Surgical Results in 80 Consecutive Patients

Background  Extradural temporopolar approach for paraclinoid lesions can provide extensive and early exposure of the anterior clinoid process, and complete mobilization and decompression of the optic nerve and internal carotid artery, which can prevent intraoperative neurovascular injury. The present study investigated the usefulness of our less invasive modified technique and discussed its operative nuances. Methods  We retrospectively reviewed medical charts of 80 consecutive patients with neoplastic (21 patients) and vascular lesions (59 patients) who underwent the modified extradural temporopolar approach between September 2009 and March 2014. Results  Preoperative visual acuity worsened in 4 patients (5.0%) and worsening of visual field function occurred in 10 patients (12.5%). Postoperative outcome was good recovery in 71 patients, moderate disability in 6, severe disability in 2, and death in 1 (due to reruptured aneurysm). No operation-related mortality occurred in the series. Conclusion  Less invasive modified extradural temporopolar approach is safe and can be recommended for the surgical treatment of deeply located aneurysms and skull base tumors to reduce the risk of intraoperative optic neurovascular injury.

The Orbitomeningeal Band as a Way to Bloodless Transcavernous Dissection and Anterior Clinoidectomy

The meningo-orbital band (MOB) is a dural fold which runs along the lateral border of the superior orbital fissure and contains few small dural veins and the orbitomeningeal artery. MOB detachment is relatively easy to understand step-wise procedure, provides a wider exposure, and better orientation thus facilitating relatively easy approach to paraclinoid and cavernous sinus region. The present microsurgical technique helps to preserve the true cavernous membrane and thereby providing almost bloodless dissection of the cavernous sinus. The same technique can be used to uncover the anterior clinoid process laterally, posteriorly, superiorly, and also in the inferolateral region thereby decreasing the risk and time of clinoidectomy.

Anterior Clinoid Metastasis Removed Extradurally: First Case Report

Background  We report a case of isolated metastasis on the anterior clinoid process (ACP) mimicking meningioma.

Clinical Presentation  A 58-year-old male presented with headaches, right-sided visual disturbances, and blurred and double vision. The cause of double vision was partial weakness of the right III nerve, resulting from compression of the nerve by “hypertrophied” tumor-involved right anterior clinoid. Medical history revealed two primary malignant tumors—male breast cancer and prostate cancer (diagnosed 6 and 18 months prior, respectively). The patient was treated with chemotherapy and showed no signs of active disease, recurrence, or metastasis. Postcontrast head magnetic resonance imaging (MRI) showed extra-axial well-bordered enhancing mass measuring 1.6 × 1.1 × 1 × 1 cm (anteroposterior, transverse, and craniocaudal dimensions) on the ACP, resembling a clinoidal meningioma. Extradural clinoidectomy with tumor resection was performed via right orbitozygomatic pretemporal skull base approach. Visual symptoms improved. Follow-up MRI showed no signs of tumor residual or recurrence.

Conclusion  This is the first case report of a metastasis of any kind on ACP. Metastasis should be included as a part of the differential diagnosis of lesions of the anterior clinoid. Extradural clinoidectomy is a safe and effective method in the treatment of these tumors.

Transcavernous Approach to the Basilar Apex: A Cadaveric Prosection

The transcavernous approach to the basilar artery, as initially described by Dolenc, is one of the most common and elegant approaches to the region. It affords a generous working and viewing angle, but it can be technically challenging and requires attention to detail at each step. We investigate this approach in this report via a cadaveric prosection with a focus on the value of each of the component steps in improving surgical view and exposure. The transcavernous approach steps are divided into extradural stages: orbitozygomatic osteotomy (a modern adjunct to Dolenc's original description), drilling of the lesser sphenoid wing, and anterior clinoidectomy; and intradural stages: wide splitting of the Sylvian fissure, unroofing of the oculomotor and trochlear nerves, and posterior clinoidectomy. The surgical windows afforded by each step in the approach are illustrated using microscopic images taken during the cadaveric prosection of a donor who happened to harbor a basilar apex aneurysm. An illustrative case and artist illustrations are used to emphasize the relative value of each step of the transcavernous exposure.

Modified Extradural Temporopolar Approach for Paraclinoid Aneurysms: Operative Nuance and Surgical Result

BACKGROUND

Extradural temporopolar approach can provide extensive exposure of the anterior clinoid process, which can prevent intraoperative neurovascular injury in anterior clinoidectomy for paraclinoid aneurysms. The present study investigates the usefulness of this modified technique, and operative nuances are discussed here.

METHODS

We retrospectively reviewed the medical charts of 30 consecutive patients with paraclinoid aneurysms who underwent treatment with this modified extradural temporopolar approach between September 2009 and March 2016.

RESULTS

Worsening of visual acuity was documented postoperatively in three patients (10.0%), and visual field function worsened in three patients (10.0%). Postoperative outcome was good recovery in all patients. No operation-related mortality occurred in the series.

CONCLUSION

Extradural anterior clinoidectomy via the modified extradural temporopolar approach is safe and may be recommended for surgical treatment of paraclinoid aneurysms to reduce the risk of intraoperative optic neurovascular injury.

Suction Decompression during Anterior Clinoidectomy for Direct Clipping of Paraclinoid Aneurysm Involving the Anterior Clinoid Process

Surgical clipping of paraclinoid aneurysms involving the anterior clinoid process (ACP) can present great challenges because strong adhesion may hinder dissection of the surrounding anatomical structures from the aneurysm dome. On the other hand, retrograde suction decompression (RSD) through direct puncture of the common carotid artery is a useful adjunct technique for clipping of these aneurysms. The present case illustrates that direct clipping of paraclinoid aneurysms involving the ACP can be achieved safely and less invasively using RSD during anterior clinoidectomy. Postoperatively, her clinical course was uneventful. RSD is a useful technique during anterior clinoidectomy in direct clipping of paraclinoid aneurysms involving the ACP.

The Microsurgical Relationships between Internal Carotid-Posterior Communicating Artery Aneurysms and the Skull Base

Objective  This study aimed to review the anatomical and clinical characteristics of internal carotid-posterior communicating artery (IC-PC) aneurysms, especially those located close to the skull base. Methods  The microsurgical anatomy around the posterior communicating artery (PComA) was examined in a dry skull and five formalin-fixed human cadaveric heads. The clinical characteristics of 37 patients with 39 IC-PC aneurysms, who were treated microsurgically between April 2008 and July 2016, were retrospectively reviewed. Results  The anterior clinoid process (ACP), as well as the anterior petroclinoidal dural fold (APF), which forms part of the oculomotor triangle, are closely related to the origin of the PComA. Among the 39 IC-PC aneurysms, anterior clinoidectomy was performed on 4 (10.3%) and a partial resection of the APF was performed on 2 (5.1%). Both of these aneurysms projected inferior to the tentorium, or at least part of the aneurysm's dome was inferior to the tentorium. Conclusion  Proximally located IC-PC aneurysms have an especially close relationship with the ACP and APF. We should be familiar with the anatomical relationship between IC-PC aneurysms and the structures of the skull base to avoid hazardous complications.

Frontolateral Approach Combined with Endoscopic Endonasal Extradural Posterior Clinoidectomy to the Upper Clival Region: Anatomic and Feasibility Study

BACKGROUND

Surgical management of lesions located in the upper clival region is challenging. Complex open transcranial approaches have been used to reach surgical targets in these areas. The frontotemporozygomatic approach combined with an intradural posterior clinoidectomy has been proposed as the most reliable route to manage such lesions. We investigated combining a minimally invasive endoscopic endonasal extradural posterior clinoidectomy (EPC) with a standard frontolateral approach to expand the working area within the upper clival region.

METHODS

Investigators dissected 10 human cadaveric heads at the Laboratory of Surgical NeuroAnatomy of the University of Barcelona. The heads were positioned to simulate a supine position, enabling the simultaneous use of both endonasal and frontolateral routes. The dissections were divided into 3 steps-standard frontolateral approach, EPC, and re-evaluation of the frontolateral route-aiming to compare the surgical exposure before and after EPC.

RESULTS

After EPC, through the frontolateral pathway it was possible to improve visualization and working angles to the interpeduncular fossa and retrosellar and upper clival regions. Increase in extension of the carotid-oculomotor window was 7 mm and 10 mm before and after the posterior clinoidectomy, respectively.

CONCLUSIONS

EPC provided extra working space for the frontolateral approach to the upper clival area with 42.8% expansion of the carotid-oculomotor triangle. Surgical series are needed to demonstrate clinical advantages and disadvantages of this novel combined approach.

Modified extradural temporopolar approach with mini-peeling of dura propria for paraclinoid and/or parasellar tumors: Operative technique and nuances

Background:

Modified extradural temporopolar approach (EDTPA) with mini-peeling of the dura propria can provide extensive exposure of the anterior clinoid process and early exposure, as well as complete mobilization and decompression of the optic nerve and internal carotid artery, which can prevent intraoperative neurovascular injury for paraclinoid and/or parasellar lesions. The present study investigated the usefulness of this modified technique and discusses the operative nuances.

Methods:

We retrospectively reviewed medical charts of 27 consecutive patients with neoplastic paraclinoid and/or parasellar lesions who underwent this modified approach between September 2009 and August 2016.

Results:

Preoperative visual acuity worsened in 2 patients (7.4%), and worsening of visual field function occurred in 2 patients (7.4%). Postoperative outcome was good recovery in 25 patients (92.6%) and moderate disability in 2 (7.4%). No operation-related mortality occurred in the series.

Conclusions:

The modified EDTPA is safe and recommended for surgical treatment of paraclinoid and/or parasellar tumors to reduce the risk of intraoperative optic neurovascular injury.

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.

Quantitative Anterior and Posterior Clinoidectomy Analysis and Mobilization of the Oculomotor Nerve during Surgical Exposure of the Basilar Apex Using Frameless Stereotaxis

Background  Anterior and posterior clinoidectomies have been proposed to augment exposure of the basilar apex. A sequential quantitative benefit analysis offered by these maneuvers has not been reported. Methods  Fourteen datasets from eight cadaveric specimens were analyzed. A modified orbitozygomatic frontotemporal craniotomy was performed. The extent of proximal control of the basilar artery was determined through the exposed opticocarotid and carotidoculomotor triangles before and after clinoidectomies and mobilization of the third nerve at the porous oculomotarius. Results  Removal of the anterior and posterior clinoids significantly improved proximal basilar artery access ( p  < 0.012) and increased the opticocarotid triangle and carotidoculomotor triangle areas ( p  < 0.017). Surgical freedom increased inferosuperiorally in the opticocarotid triangle following anterior clinoidectomy ( p  < 0.047) and in carotidoculomotor triangle following posterior clinoidectomy ( p  < 0.047). Mobilization of the third nerve increased surgical freedom in the mediolateral projection of the carotidoculomotor triangle ( p  < 0.047). Conclusion  Anterior and posterior clinoidectomies significantly improved the area of exposure of the opticocarotid triangle, carotidoculomotor triangle, and the exposed length of the basilar artery available for proximal control. This improvement is extremely important for large or giant aneurysms of the upper basilar artery or aneurysms hidden by the posterior clinoid.

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.

Radical resection of a craniopharyngioma via the extradural anterior temporal approach with zygomatic arch osteotomy

BACKGROUND

Though the extradural anterior temporal approach (EDATA) with zygomatic osteotomy is useful, there are only few reports of this approach being used for craniopharyngioma resection. Herein, we report our surgical case series and the technical importance of EDATA for the radical removal of a craniopharyngioma.

METHODS

We report 7 cases of craniopharyngiomas treated surgically between April 1999 and October 2015. The surgical approaches, clinical presentation, pre and postoperative radiographic examination results, surgical outcomes, and morbidity were analyzed.

RESULTS

The mean follow-up period was 89.1 months. The surgical approach was EDATA with zygomatic osteotomy in 4, combined interhemispheric translamina terminalis approach (IHTLA) and trans-sylvian anterior temporal approach (ATA) in 2, and IHTLA in 1 patient. Complete tumor resection was achieved in all cases, without any recurrence during the follow-up period. Transient morbidities were oculomotor nerve palsy in 2, and meningitis and hydrocephalus in 1 patient. There was 1 case of permanent morbidity due to hydrocephalus that needed a ventriculoperitoneal shunt, and 1 case of blindness on the operative side. Visual acuity and visual field improved in 4 cases, showed no change in 2 cases, and deteriorated in 1 case. Though the pituitary stalk was preserved in 2 cases, all 7 cases needed total hormone replacement therapy.

CONCLUSION

EDATA with zygomatic osteotomy ensures sufficient mobility of the internal carotid artery, and provides a good lateral and look up operative view. Hence, it can be used effectively for radical resection of craniopharyngiomas through the opticocarotid space and retrocarotid space.

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.

Microsurgical and histological identification and definition of an interdural incision zone in the dorsolateral cavernous sinus

OBJECTIVES

The anatomy of the cavernous sinus is described controversially in a number of publications. In the present cadaveric study, the architecture of the dorsolateral wall of the cavernous sinus is studied microsurgically and histologically.

MATERIALS AND METHODS

Twenty cadaveric skulls have been dissected through a classical surgical frontotemporal approach. The temporal skull base was flattened and anatomical landmarks like the meningo-orbital band, superior orbital fissure, foramina rotundum, ovale, and spinosum were identified. Lateral of the trigeminal foramina, the dura was cut and the periosteal dural layer was separated from the meningeal layer, identifying an interdural zone. The length and the extent of this zone were evaluated. The dural architecture of the interdural incision zone was examined histologically.

RESULTS

In all specimens, two dural layers lateral of the trigeminal foramina could be separated. The identified interdural incision zone extended in a length of 3.8-6.4 cm in the antero-posterior direction. The zone could be followed medially to the superior orbital fissure for 5.3 mm and lateral of the foramen spinosum for 6.4 mm. The separation of the dural layers allowed the approach to the superior border of the cavernous sinus through this interdural incision zone. The histological analysis of the interdural incision zone showed clearly the existence of two dural layers.

CONCLUSIONS

The architecture of the temporal-fossa-dura allows the microsurgical separation of two meningeal dural layers through a length of 5-6 cm next to the trigeminal foramina. Opening this interdural incision zone allowed exploring the superior border of the cavernous sinus.

Anatomic comparison of the endonasal and transpetrosal approaches for interpeduncular fossa access

OBJECT

The interpeduncular cistern, including the retrochiasmatic area, is one of the most challenging regions to approach surgically. Various conventional approaches to this region have been described; however, only the endoscopic endonasal approach via the dorsum sellae and the transpetrosal approach provide ideal exposure with a caudal-cranial view. The authors compared these 2 approaches to clarify their limitations and intrinsic advantages for access to the interpeduncular cistern.

METHODS

Four fresh cadaver heads were studied. An endoscopic endonasal approach via the dorsum sellae with pituitary transposition was performed to expose the interpeduncular cistern. A transpetrosal approach was performed bilaterally, combining a retrolabyrinthine presigmoid and a subtemporal transtentorium approach. Water balloons were used to simulate space-occupying lesions. "Water balloon tumors" (WBTs), inflated to 2 different volumes (0.5 and 1.0 ml), were placed in the interpeduncular cistern to compare visualization using the 2 approaches. The distances between cranial nerve (CN) III and the posterior communicating artery (PCoA) and between CN III and the edge of the tentorium were measured through a transpetrosal approach to determine the width of surgical corridors using 0- to 6-ml WBTs in the interpeduncular cistern (n = 8).

RESULTS

Both approaches provided adequate exposure of the interpeduncular cistern. The endoscopic endonasal approach yielded a good visualization of both CN III and the PCoA when a WBT was in the interpeduncular cistern. Visualization of the contralateral anatomical structures was impaired in the transpetrosal approach. The surgical corridor to the interpeduncular cistern via the transpetrosal approach was narrow when the WBT volume was small, but its width increased as the WBT volume increased. There was a statistically significant increase in the maximum distance between CN III and the PCoA (p = 0.047) and between CN III and the tentorium (p = 0.029) when the WBT volume was 6 ml.

CONCLUSIONS

Both approaches are valid surgical options for retrochiasmatic lesions such as craniopharyngiomas. The endoscopic endonasal approach via the dorsum sellae provides a direct and wide exposure of the interpeduncular cistern with negligible neurovascular manipulation. The transpetrosal approach also allows direct access to the interpeduncular cistern without pituitary manipulation; however, the surgical corridor is narrow due to the surrounding neurovascular structures and affords poor contralateral visibility. Conversely, in the presence of large or giant tumors in the interpeduncular cistern, which widen the spaces between neurovascular structures, the transpetrosal approach becomes a superior route, whereas the endoscopic endonasal approach may provide limited freedom of movement in the lateral extension.

Extradural temporopolar approach for parahypothalamic hypothalamic hamartoma and use of posterior communicating artery as resection margin pointer

BACKGROUND

Hypothalamic hamartomas (HH) are malformations originating from the hypothalamus and are associated with seizures, hormonal and behavioral abnormalities.

METHOD

Most patients, especially those with a typical syndrome characterized by gelastic seizures, precocious puberty, cognitive decline, and behavior problems, are diagnosed in childhood. Pedunculated and parahypothalamic types of hamartomas are attached to the floor by a narrow or wide peduncle in the absence of distortion of the overlying hypothalamus. This location is most commonly associated with a clinical presentation of precocious puberty, and surgical removal has proved curative in small case series. Enthusiastic resection of hypothalamic lesions are known to produce severe hypothalamic disturbance while under resection might mean inadequate response to surgery.

CONCLUSIONS

In this article, the authors describe the use of extradural temporopolar approach to hypothalamic hamartoma as an improvisation to improve access with reduced morbidity and describe a surgical nuance of using posterior communicating artery to determine a safe but maximal resection margin.

Microsurgical management of aneurysms of the superior cerebellar artery - lessons learnt: An experience of 14 consecutive cases and review of the literature

Objective:

This is a retrospective study from January 2002 to December 2012 analyzing the results of microsurgical clipping for aneurysms arising from the superior cerebellar artery (SCA).

Materials and Methods:

All patients with SCA were evaluated with computerized tomography angiography and/or digital subtraction angiography (DSA) prior to surgery. All patients in our series underwent microsurgical clipping and postoperative DSA to assess the extent of aneurysm occlusion. The Glasgow outcome scale (GOS) and the modified Rankin's scale (mRS) were used to grade their postoperative neurological status at discharge and 6 months, respectively.

Results:

Fourteen patients had SCA aneurysms (ruptured-9, unruptured-5). There were 10 females and 4 males with the mean age of 47.2 years (median - 46 years, range = 24–66 years). Subarachnoid hemorrhage (SAH) was seen in 11 patients. The mean duration of symptoms was 2.5 days (range = 1–7 days). The WFNS score at presentation was as follows: Grade 1 in 10 cases, II in 2 cases, III in 1 case and IV in 1 case. In the 9 cases with ruptured SCA aneurysm, average size of the ruptured aneurysms was 7.3 mm (range = 2.5–27 mm, median = 4.9 mm). The subtemporal approach was used in the first 7 cases. The extradural temporopolar (EDTP) approach was used in the last 5 cases. Complications include vasospasm (n = 6), third nerve palsy (n = 5) and hydrocephalus (n = 3). Two patients died following surgery. At mean follow-up 33.8 months (median - 25 months, range = 19–96 months), no patient had a rebleed. At discharge 9 (64%), had a GOS of 4 or 5 and 3 (21%) had a GOS of 3. At 6 months follow-up, 10/14 (71%) patients had mRS of 0–2, and 2 (14%) had mRS of 5.

Conclusions:

Aneurysms of the SCA are uncommon and tend to rupture even when the aneurysm size is small (<7 mm). They commonly present with SAH. The EDTP approach avoids complication caused by temporal lobe retraction and injury to the vein of Labbe.

A modified anterior temporal approach for low-position aneurysms of the upper basilar complex

Background:

Although surgery for aneurysms of the upper basilar complex is generally accomplished by a pterional or subtemporal approach, both techniques have disadvantages. Therefore, attempts have been made to combine both the approaches, such as an anterior temporal approach, which exposes the anterior aspect of the temporal lobe during standard fronto-temporal craniotomy. However, in all these techniques, the temporal vein is sacrificed to allow posterior retraction of the temporal lobe, which may cause venous infarction in the temporal lobe.

Methods:

Our institutional review board approved this prospective study. We modified the anterior temporal approach for low-position aneurysms of the upper basilar complex by performing posterior clinoidectomy as necessary, thereby preventing the sacrifice of all vessels.

Results:

From 2007 to 2014, seven patients were operated on using this modified approach, and four patients underwent additional posterior clinoidectomy. Complete clip ligation was performed for all aneurysms without sacrificing any vessels, and there were no permanent complications attributable to manipulation for clipping or posterior clinoidectomy.

Conclusions:

The modified anterior temporal approach allows a wider operating field within the retro-carotid space, without sacrificing any vessels, and permits safer posterior clinoidectomy and aneurysm clipping in patients with low-position aneurysms of the basilar complex.