S. Froelich

Large sphenoid wing meningiomas involving the cavernous sinus: Conservative surgical strategies for better functional outcomes

OBJECTIVE:The ability to resect meningiomas that involve the medial and anterior compartments of the cavernous sinus has been refuted. In this retrospective study, we determined the efficacy of total resection of meningiomas that invade the cavernous sinus but are restricted to the lateral compartment. METHODS:We reviewed the charts of 38 consecutive patients with sphenocavernous, clinoidocavernous, and sphenoclinoidocavernous meningiomas who underwent surgical treatment. We assessed early and late cranial nerve morbidity, extent of resection, and long-term outcome (mean, 96 mo). RESULTS:In all patients, tumors exceeded 3 cm diameter. In 22 of 24 patients, total microscopic excision was achieved in tumors that involved only the lateral compartment of the cavernous sinus and touched or partially encased the cavernous internal carotid artery (i.e., modified Hirsch Grades 0 and 1, respectively). In 2 of 24 patients, remaining tumor infiltrated the superior orbital fissure. All 14 patients who had tumors that encased (with or without narrowing) the cavernous segment of the internal carotid artery (Hirsch Grades 2–4) underwent incomplete resection. Among 38 patients, mortality was 0%, late cranial nerve deficits remained in 6 (16%), and late Karnofsky Performance Scale scores exceeded 90 in 34 patients (90%). Four patients (10.5%) developed a recurrence or regrowth. Of 20 patients who were treated with either linear accelerator-based stereotactic radiosurgery or fractionated conformal radiotherapy, 11 had residual tumor and a moderate to high proliferative index, 4 had atypical tumors and 1 had angioblastic meningioma after total excision, 2 had regrowth, and 2 had recurrent tumors. In 18 (90%) of the 20 patients who underwent radiation, tumor size was reduced or controlled. CONCLUSION:On the basis of this study and a review of the literature, we demonstrate that sphenocavernous, clinoidocavernous, and sphenoclinoidocavernous meningiomas of Hirsch Grades 0 and 1 can be excised from the lateral compartment of the cavernous sinus without postoperative mortality and with acceptable rates of morbidity. Residual tumor in the medial compartment (Hirsch Grades 2–4) may be treated with some form of radiation therapy or observation.

The One-Piece Orbitozygomatic Approach: The MacCarty Burr Hole and the Inferior Orbital Fissure as Keys to Technique and Application

Summary Objective. Use of the MacCarty keyhole burr hole and the inferior orbital fissure provides simplicity and safety to perform the one-piece frontotemporal orbitozygomatic (FTOZ1) approach. Methods. We performed the FTOZ1 approach with its three subtypes (i.e., total, temporal, and frontal) in cadaveric head specimens in the Goodyear Laboratory and subsequently in surgical cases. Results. The orbitozygomatic osteotomy, when added to a frontotemporal craniotomy, comprises the frontotemporal orbitozygomatic (FTOZ) approach, provides an expanded exposure to the anterior and middle cranial fossae, and enables the surgeon to create a window to the posterior cranial fossa. The MacCarty burr hole is used to facilitate orbital cuts, and the anterolateral portion of the inferior orbital fissure connects the orbital cuts to the zygomatic cuts. This allows the FTOZ1 craniotomy flap to be “out-fractured” with ease. The three types of FTOZ1 approach, i.e., the total, the temporal, and the frontal, are described step by step. Conclusions. Understanding the MacCarty keyhole burr hole and the microsurgical anatomy of the inferior orbital fissure is essential to performing the FTOZ1 approach. The three types of FTOZ1 approach enable the surgeon to tailor the approach according to the surgical exposure needed for each lesion.

Retrospective Comparison of Chemoradiotherapy Followed by Adjuvant Chemotherapy, With or Without Prior Gliadel Implantation (Carmustine) After Initial Surgery in Patients With Newly Diagnosed High-Grade Gliomas

PURPOSE Retrospective study of patients treated for high-grade glioma, with or without biodegradable carmustine wafers and according to the Stupp protocol. METHODS AND MATERIALS Between May 2007 and June 2008, 65 patients underwent surgery for high-grade glioma, 28 had implantation of Gliadel and 37 patients did not. Patients received radiotherapy with concomitant temozolomide followed by 5 consecutive days of temozolomide every month for 6 months. RESULTS Overall median follow-up was 17.1 months; the median relapse-free survival (RFS) was 14 months with a RFS of 54% at 12 months, and 38% at 24 months. For patient with and without Gliadel, median and 1-year RFS were 12.9 months and 52% vs. 14 months and 42%, respectively (p = 0.89). According to pathology, Gliadel did not influence RFS of patients with Grade III or glioblastoma. However, for all patients, in multivariate analysis, non-methylated methylguanine methyltransferase (MGMT) was the only unfavorable prognostic factor of RFS (p = 0.017; HR 2.8; CI [1.2-7]). Median overall survival (OS) was 20.8 months; the OS rate at 12 months was 78.5%, and at 24 months 35.4%. For patients treated with and without Gliadel, median and 1-year OS were 20.6 months and 78.6% vs. 20.8 months and 78.4%, respectively. According to pathology, Gliadel did not influence OS of patients with Grade III or glioblastoma. For all patients, in multivariate analysis, unfavorable prognosticators for OS were non-methylated MGMT (p = 0.001; HR: 6.5; CI [2-20]) and irradiation dose <60 Gy (p = 0.02; HR: 6.3; CI [2-20]). With carmustine wafers, before irradiation, median gross tumor volume plus edema was 84 mL (27-229), whereas it was 68 mL (10-362) without carmustine (p = nonsignificant). Four cases of Grade 3 thrombopenia occurred, all in the carmustine wafer group. CONCLUSION In patients with high-grade gliomas, adding Gliadel before performing a Stupp protocol did not improve survival.

Maximizing the extent of tumor resection during transsphenoidal surgery for pituitary macroadenomas: can endoscopy replace intraoperative magnetic resonance imaging?

OBJECT Endoscopic approaches to pituitary tumors have become an effective alternative to traditional microscopic transsphenoidal approaches. Despite a proven potential to decrease unexpected residual tumor, intraoperative MR (iMR) imaging is infrequently used even in the few operating environments in which such technology is available. Its use is prohibitive because of its cost, increased complexity, and longer operative times. The authors assessed the potential of intrasellar endoscopy to replace the need for iMR imaging without sacrificing the maximum extent of resection. METHODS In this retrospective study, 27 consecutive patients underwent fully endoscopic resection of pituitary macroadenomas. Intrasellar endoscopy was used to determine the presence of residual tumor within the sella turcica and tumor cavity. Intraoperative MR imaging was used to identify rates of unexpected residual tumor and the need for further tumor resection. RESULTS Intraoperative estimates of the extent of tumor resection were correct in 23 patients (85%). Of 4 patients with unacceptable tumor residuals, 3 underwent further tumor resection. After iMR imaging, the rate of successful completion of the planned extent of resection increased to 26 patients (96%). Rates of both endocrinopathy reversal and postoperative complications were consistent with previously published results for microscopic and endoscopic resection techniques. CONCLUSIONS The findings in this study provided quantitative evidence that intrasellar endoscopy has significant promise for maximizing the extent of tumor resection and is a useful adjunct to surgical approaches to pituitary tumors, particularly when iMR imaging is unavailable. A larger prospective study on the extent of resection following endoscopic transsphenoidal surgery would strengthen these findings.

Microsurgical and endoscopic anatomy of Liliequist's membrane: a complex and variable structure of the basal cisterns.

OBJECTIVE Descriptions of Liliequists membrane, as reported in the literature, vary considerably. In our cadaveric study of Liliequists membrane, we attempted to clarify and define its anatomic features and boundaries, as well as its relationship with surrounding neurovascular structures. We describe the embryology of this membrane as a remnant of the primary tentorium. The clinical significance of our findings is discussed with respect to third ventriculostomy and surgical approaches to basilar tip aneurysms, suprasellar arachnoid cysts, and perimesencephalic hemorrhage. METHODS Thirteen formalin-fixed adult cadaveric heads were injected with colored silicone. After endoscopic exploration of Liliequists membrane, a bilateral frontal craniotomy was performed, and the frontal lobes were removed to fully expose Liliequists membrane. RESULTS Liliequists membrane is a complex and highly variable structure that is composed of either a single membrane or two leaves. The membrane was absent in two specimens without any clear demarcation between the interpeduncular, prepontine, and chiasmatic cisterns. CONCLUSION Understanding the variable anatomy of Liliequists membrane is important, particularly to improve current and forthcoming microsurgical and endoscopic neurosurgical procedures. It is important as a surgical landmark in various neurosurgical operations and in the physiopathology of several pathological processes (suprasellar arachnoid cysts and perimesencephalic hemorrhage).

Refinement of the extradural anterior clinoidectomy: Surgical anatomy of the orbitotemporal periosteal fold

OBJECTIVE Extradural removal of the anterior clinoid process is technically challenging because of the limited exposure. In our study of the extradural anterior clinoidectomy, we describe anatomic details and landmarks to facilitate sectioning of the orbitotemporal periosteal fold and elevation of the temporal fossa dura from the superior orbital fissure. We assess the morbidity associated with these procedures as well as compare the indications, advantages, and disadvantages of intra-versus extradural clinoidectomy. METHODS Of five formalin-fixed cadaveric heads, four were used for cadaveric dissections and one was used for histological examination. RESULTS Sectioning of the orbitotemporal periosteal fold revealed a cleavage plane between the temporal fossa dura and a thin layer of connective tissue that covers the superior orbital fissure. The lacrimal nerve coursed immediately medial to this surgically created cleavage plane. The superior orbital vein crossed laterally under the cranial nerves, which pass through the superior orbital fissure. This vein is particularly vulnerable as it is composed only of endothelium and a basal membrane. CONCLUSION Both intra- and extradural techniques for anterior clinoidectomy are important parts of the neurosurgical armamentarium. Sharp incision of the orbitotemporal periosteal fold to increase the extradural exposure of the anterior clinoid process should be made at the level of the sphenoid ridge and restricted to the periosteal bridge. Subsequent blunt elevation of the temporal fossa dura should be performed; however, peeling of the temporal fossa dura should be limited to avoid cranial nerve morbidity.

Anterior communicating artery aneurysm clipped via an endoscopic endonasal approach: technical note.

BACKGROUND: The anterior communicating artery (AcoA) aneurysm is one of the most challenging aneurysms. As endovascular techniques evolve, a remaining challenge is the reduction of complications related to the surgical approach. Although the endonasal approach is widely used for pituitary adenomas and is increasingly popular for suprasellar tumors, only 2 aneurysm cases have been reported. OBJECTIVE: To the best of our knowledge, we are reporting the first case of successful endoscopic endonasal clipping of an unruptured ACoA aneurysm. METHODS: An ACoA aneurysm was discovered in a 55-year-old man before he was to undergo an endoscopic biopsy of an orbital lesion. Because of the operative corridor formed during this first operation and ideal conformation of the aneurysm for this line of sight, we formulated an endoscopic route for this ACoA aneurysm. RESULTS: An endoscopic endonasal transplanum-transtuberculum approach was performed. Proximal and distal control was obtained, and the AcoA aneurysm was successfully clipped. The postoperative course was uneventful with a rapid recovery. CONCLUSION: The endoscopic approach provided another option the value of which value must be weighed in terms not only of feasibility but the patients best interest. We caution extreme prudence if considering this procedure as an alternative to well-established techniques. Yet its upward route offers limited retraction for deep-seated lesions. Rapid progress of endoscopic techniques may prove promising for well-selected cases of ACoA aneurysms.

Prognostic and Therapeutic Markers in Chordomas: A Study of 287 Tumors

Chordomas are slow-growing malignant neoplasms. Determination of histopathologic prognostic factors using a large cohort study has been limited by their low incidence. In this retrospective study, we investigated the clinical, histopathologic, and immunohistochemical prognostic factors in 287 chordomas from 111 patients assessed by central pathologic review. Expression patterns of a variety of markers, including vascular endothelial growth factor (VEGF), mTOR pathway, c-kit, HER2, epidermal growth factor receptor (EGFR) and STAT3, and KRAS, BRAF, EGFR, and PIK3CA mutations were analyzed. On univariate analysis, the results confirm surgery as the best treatment, as judged by patient progression-free survival (PFS) and overall survival (OS). Proton therapy, the presence of a dedifferentiated component, mitotic figures, and Ki67 and p53 labeling indices correlated with PFS. Necrosis and apoptosis correlated with OS. Based on these findings, we propose a histopathologic grading system that correlates with PFS and OS. On multivariate analysis, extent of resection, tumor grade, and proton therapy were independent prognostic factors of PFS; extent of resection, tumor location, and grade were independent prognostic factors of OS. Based on the expression of EGFR, pSTAT3, VEGF, and mTOR pathway proteins, (in 85.9%, 79.1%, 85.7%, and 46% of chordomas, respectively), and 2 new mutations in the PIK3CA gene, we also provide evidence for potential therapeutic targets.

Minimally invasive transpalpebral "eyelid" approach to the anterior cranial base.

BACKGROUND Supra orbital frontal minicraniotomy is one of the most commonly used minimally invasive approaches for anterior cranial fossa lesions. OBJECTIVE To describe our experience with the transpalpebral “eyelid” incision to obtain access to the anterior cranial fossa. METHODS We describe the approach and technique of the transpalpebral eyelid incision in a step-by-step fashion and discuss the results of 40 cases for which the eyelid incision was used. We retrospectively reviewed the charts of these patients to analyze outcomes with regard to opening and closing time, length of hospital stay, residual aneurysm or Simpson grade for resection, complications, and cosmetic result. RESULTS We treated 31 anterior circulation aneurysms (28 unruptured and 3 ruptured), 7 anterior skull base meningiomas, 1 frontal low-grade glioma, and 1 frontal cavernoma using the transpalpebral incision. Opening time was about 45 to 60 minutes, and closure time from dura to skin was about 45 to 60 minutes. The hospital length of stay was similar to that in our open craniotomy cases. No residual aneurysm was demonstrated in the follow-up studies of all 31 aneurysms. Simpson grade I resection was achieved in 6 meningiomas. Complications included 1 postoperative eyelid hematoma, 2 postoperative infections, and a subclinical stroke discovered on postoperative imaging. Excellent cosmetic outcome was accomplished in 39 of 40 patients. CONCLUSION The transpalpebral approach provides dissection in natural anatomical planes, affords preservation of the frontalis muscle, avoids injury to nerve VII branches, and results in an excellent cosmetic outcome.

Endoscopic, Endonasal Variability in the Anatomy of the Internal Carotid Artery

BACKGROUND Classic three-dimensional schemas of the internal carotid artery (ICA) for transcranial approaches do not necessarily apply to two-dimensional endoscopic views. Modifying an existing ICA segment classification, we define endoscopic orientation for the lacerum (C3) to clinoid (C5) segments through an endonasal approach. METHODS In 20 cadaveric heads, we classified endoscopic appearance based on shape and angulation of C3 to C5 segments. Distances were measured between both arteries, and between the ICA and pituitary gland. RESULTS We identified 4 common ICA patterns: types I through III matched side-to-side, whereas type IV was asymmetric. In 80% of specimens, the pituitary gland had direct contact with the ICA. In 20% of specimens, a space existed between the pituitary gland and the cavernous segment. Access to the posterior aspect of the cavernous sinus medial to the cavernous segment was possible without retraction of the artery or pituitary gland. Spaces between the lacerum and cavernous segments were trapezoid (80%) and hourglass (20%). CONCLUSIONS Distinguishing which ICA type courses between the lacerum and clinoid segments can help clarify the relationships between the artery and its surrounding structures during endoscopic approaches. Adapting the classic terminology of ICA segments provided consistency of endoscopic relevance, defined potential endoscopic corridors, and highlighted the critical step of arterial contact.