Standard Frontotemporal Craniotomy Research Articles

Mini Temporal Craniotomy Using Anatomical Surface Landmarks for Temporal Lobe Epilepsy: Technical Note and Clinical Outcomes.

Patients with temporal lobe epilepsy are subjected to standard temporal lobectomy wherever indicated. This is performed using a reverse question mark flap and a standard frontotemporal craniotomy. We describe the technique of minitemporal craniotomy (3 × 3cms) for temporal lobe epilepsy (TLE) and analyze the clinical outcomes of patients operated using this approach. To describe the technique of minitemporal craniotomy for TLE without navigation guidance and to analyze the clinical outcomes of patients operated using this approach. This was a retrospective analysis of all consecutive TLE cases operated at our institute from 2014 to 2019, via minitemporal craniotomy, using surface landmarks only without navigation guidance. The surgical technique, indications for surgery, and their clinical outcomes were analyzed. A total number of 48 patients underwent surgery for TLE. There were no complications except three patients who had transient hemiparesis. The average duration of hospital stay was 4 days following surgery. Out of 28 patients with mesial temporal sclerosis, 22 (82%) had international league against epilepsy, Class I seizure outcome, 4 (12.5%) had Class II outcome and 2 (5.5%) had Class III outcome. 9 patients with dysembryoplastic neurectodermal tumor (DNET), 4 gangliogliomas, 2 neurocystecercosis (NCC), all had Class I outcome. Out of the five patients with MTS and associated anterior temporal focal cortical dysplasia (FCD), four (80%) had a Class I outcome, whereas one (20%) had Class II outcome. Utilizing surface anatomical landmarks, minitemporal craniotomy can be performed in even peripheral centers without neuronavigation, with good cosmesis, seizure outcomes.

Keyhole Approach in Cerebral Aneurysm Surgeries.

Pterional approach via standard fronto-temporal craniotomy and interhemispheric approach via bifrontal craniotomy are the gold standards for clipping of cerebral aneurysms in the anterior circulation. Endovascular treatment is now widely used, but subsets of aneurysms are still indicated for surgical clipping. Modern technological advances allow less invasive clipping techniques such as the keyhole approach. This chapter discusses the surgical indications, preoperative simulation, surgical techniques, and pros and cons of keyhole (supraorbital) clipping. Selection of standard craniotomy or keyhole craniotomy should be uncontroversial, but keyhole clipping requires definite surgical indications based on the characteristics of the target aneurysm for safe clipping.

Endoscopic Endonasal versus Transcranial Optic Canal Decompression: A Morphometric, Cadaveric Study.

Introduction Decompression of the optic nerve within the optic canal is indicated for compressive visual decline. The two most common approaches utilized for optic canal decompression are a medial approach with an endoscopic endonasal approach and a lateral approach with a craniotomy. Our study is a cadaveric anatomical study comparing the length and circumference of the orbit decompressed via an endoscopic endonasal approach versus a frontotemporal craniotomy. Methods Five cadaveric specimens were utilized. Predissection computed tomography (CT) scans were performed on each specimen. On each specimen, a standard frontotemporal craniotomy with anterior clinoidectomy and superolateral orbital decompression was performed on one side and an endoscopic endonasal approach with medial wall decompression was performed on the contralateral side. Post-dissection CT scans were performed. An independent radiologist provided measurements of the length (mm) and circumference (degrees) of optic canal decompression bilaterally. Results The mean length of optic canal decompression for open and endoscopic approach was 13 mm (range 12-15 mm) and 12.4 mm (range 10-16 mm), respectively. The mean circumference of decompression for open and endoscopic approaches was 252.8 degrees (range 205-280 degrees) and 124.6 degrees (range 100-163 degrees), respectively. Conclusion The endoscopic endonasal and the transcranial approaches provide a similar length of optic canal decompression, but the transcranial approach leads to greater circumferential decompression. The endoscopic endonasal approach has the benefit of being minimally invasive, though. Ultimately, the surgical approach decision should be based on the location of the pathology and the surgeon's comfort.

Minimally Invasive Technique (Nummular Craniotomy) for Mesial Temporal Lobe Epilepsy: A Comparison of 2 Approaches

To describe our series of a minimally invasive technique using a small scalp incision and keyhole craniotomy for the removal of mesial temporal lobe structures through a transcortical approach in patients with medically intractable mesial temporal lobe epilepsy (MTLE). Studies that directly compare the clinical outcomes between minimally invasive and conventional techniques are scarce, and this information is lacking in the literature. The study enrolled 73 consecutive patients with refractory MTLE and unilateral hippocampal sclerosis; 30 patients were operated on with standard frontotemporal craniotomy between 2010 and 2013 and 43 patients were operated with a minimally invasive craniotomy (nummular craniotomy) between 2014 and 2016. The preoperative evaluation included clinical history, physical examination, video-electroencephalography, neuropsychologic assessment, and magnetic resonance imaging including thin-section coronal sequences. There were no deaths in either group. Postoperative complications in the standard frontotemporal craniotomy group included temporal muscle atrophy (n= 4; 13.3%), cerebrospinal fluid leakage (n= 1; 3.3%), and wound infection (n= 1; 3.3%). No complications were observed in the keyhole craniotomy group. There was no between-group difference in postoperative seizure control. The mean Engel class I seizure-free outcome was 90.4% in the standard frontotemporal craniotomy group and 90.7% in the nummular craniotomy group (P > 0.05). Lengths of hospitalization (2.81 vs. 4.37 days, P < 0.001) and operative time (85.79 vs. 142.73 minutes, P < 0.001) were lower in the keyhole than in the standard frontotemporal craniotomy group, respectively. The nummular technique was associated with faster recovery, early hospital discharge, and fewer complications than the standard technique. No differences were observed in postoperative seizure control. Keyhole craniotomy is a safe, easy, and effective treatment option for medically intractable MTLE.

Moyamoya Disease Associated with Tuberculum Sellae Meningioma and Cavernous Sinus Hemangioma

Primary moyamoya disease associated with skull base tumors has been reported only rarely in the literature. Surgical treatment can be complicated due to the compensatory collateral circulation through meningeal and leptomeningeal anastomosis. A standard frontotemporal craniotomy may interrupt critical transdural anastomoses. We report a case of primary moyamoya disease coexisting with tuberculum sellae meningioma and left cavernous sinus hemangioma. Simultaneous management of tuberculum sellae meningioma and moyamoya disease was performed using a left modified pterional incision. Two separate bone windows were opened to protect the transdural anastomosis via the middle meningeal artery. The tuberculum sellae meningioma was successfully removed through a small frontal craniotomy, and encephaloduromyosynangiosis was used to treat moyamoya disease through a temporoparietal craniotomy. Finally, CyberKnife radiotherapy was used to treat the left cavernous sinus hemangioma at 6 weeks after the initial operation. The patient recovered well without complications. This is the first report of moyamoya disease associated with tuberculum sellae meningioma and cavernous sinus hemangioma. With careful bone flap design, moyamoya disease and skull base tumors can be treated simultaneously. Care should be taken to avoid interruption of critical dural-pial collaterals and injury to fragile moyamoya vessels.

Histology of the distal dural ring.

The distal dural ring (DDR) is a conserved intracranial anatomic structure marking the boundary point at which the internal carotid artery (ICA) exits the cavernous sinus (CS) and enters the subarachnoid space. Although the CS has been well described in a range of anatomic studies, to our knowledge no prior study has analyzed the histologic relationship between the ICA and DDR. Correspondingly, our objective was to assess the relationship of the DDR to the ICA and determine whether the DDR can be dissected from the ICA and thus divided, or can only be circumferentially trimmed around the artery. The authors examined ten fresh-frozen, adult cadaveric specimens. A standard frontotemporal craniotomy, orbito-optic osteotomy, and extradural anterior clinoidectomy was performed bilaterally. The cavernous ICA, DDR, and supraclinoid ICA were harvested as an en bloc specimen. Specimens formalin-fixed and paraffin-embedded prior to routine histochemical staining with hematoxylin and eosin and Masson trichrome. In all specimens, marked microscopic investment of the DDR throughout the ICA adventitia was noted. Dural collagen fibers extensively permeated the arterial layers superficial to the muscularis propria, with no evidence of a clear separation between the DDR and arterial adventitia. Histologic analysis suggests that the ICA and DDR are highly interrelated, continuous structures, and therefore attempted intraoperative dissection between these structures may carry an elevated risk of injury to the ICA. We correspondingly recommend careful circumferential trimming of the DDR in lieu of direct dissection in cases requiring mobilization of the clinoidal ICA. Clin. Anat. 30:742-746, 2017. © 2017Wiley Periodicals, Inc.

Voluminous Cystic Trigeminal Schwannoma: Case Report and Literature Review

Voluminous trigeminal schwannomas are rare, predominantly benign growth encapsulated tumors composed of Schwann cells with controversial surgical treatment. They account for 20% to 40% of all trigeminal schwannomas and share the same imaging findings of neurinomas elsewhere. Surgery remains the treatment of choice for most lesions as long as complete excision is feasible. A 35-year-old house wife complained of a 3-month history of progressive right visual field impairment associated with headaches. Neurological examination revealed a complete cavernous sinus syndrome. CT scanning showed a voluminous cystic mass of the right parasellar compartment extending to the optic nerve and the orbit. A concomitant MRI scan revealed more exquisite anatomical details of the lesion. The patient benefitted from a subsequent CT-angiography (not included) which excluded any vascular abnormalities associated with the tumor. Surgical excision of the tumor was warranted and the patient underwent surgery a few days after admission. A pterional extradural-intradural approach combined with incision of the lateral wall of the parasellar compartment via a standard frontotemporal craniotomy was performed and pathological examination was in favor of a cystic trigeminal schwannoma. Post-operative MRI showed a complete excision of the tumor. A 2-year follow-up yielded persistent right monocular blindness. Given this typical appearance of this lesion indicative of both cisternal and parasellar compartment extension, as well as the level of controversy surrounding surgical treatment of these particular tumors; we sought to report this rare case of a voluminous cystic trigeminal schwannoma and share our humble surgical experience of dealing with these lesions. The patient was informed that non-identifying information from the case would be submitted for publication, and she provided consent.

Endoscopic transorbital route to the cavernous sinus through the meningo-orbital band: a descriptive anatomical study.

OBJECTIVE Exposure of the cavernous sinus is technically challenging. The most common surgical approaches use well-known variations of the standard frontotemporal craniotomy. In this paper the authors describe a novel ventral route that enters the lateral wall of the cavernous sinus through an interdural corridor that includes the removal of the greater sphenoid wing via a purely endoscopic transorbital pathway. METHODS Five human cadaveric heads (10 sides) were dissected at the Laboratory of Surgical NeuroAnatomy of the University of Barcelona. To expose the lateral wall of the cavernous sinus, a superior eyelid endoscopic transorbital approach was performed and the anterior portion of the greater sphenoid wing was removed. The meningo-orbital band was exposed as the key starting point for revealing the cavernous sinus and its contents in a minimally invasive interdural fashion. RESULTS This endoscopic transorbital approach, with partial removal of the greater sphenoid wing followed by a "natural" ventral interdural dissection of the meningo-orbital band, allowed exposure of the entire lateral wall of the cavernous sinus up to the plexiform portion of the trigeminal root and the petrous bone posteriorly and the foramen spinosum, with the middle meningeal artery, laterally. CONCLUSIONS The purely endoscopic transorbital approach through the meningo-orbital band provides a direct view of the cavernous sinus through a simple and rapid means of access. Indeed, this interdural pathway lies in the same sagittal plane as the lateral wall of the cavernous sinus. Advantages include a favorable angle of attack, minimal brain retraction, and the possibility for dissection through the interdural space without entering the neurovascular compartment of the cavernous sinus. Surgical series are needed to demonstrate any clinical advantages and disadvantages of this novel route.

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.

Minicraniotomy for standard temporal lobectomy: a minimally invasive surgical approach.

Introduction. The common surgical approach for standard temporal lobectomy is a question-mark skin incision and a frontotemporal craniotomy. Herein, we describe minicraniotomy approach through a linear skin incision for standard temporal lobectomy. Methods. A retrospective observational cohort study was conducted for a group of consecutive 21 adult patients (group I) who underwent minicraniotomy for standard temporal lobectomy utilizing a linear skin incision. This group was compared to a consecutive 17 adult patients (group II) who previously underwent a reverse question-mark skin incision and standard frontotemporal craniotomy. Results. The mean age was 29 and 23 for groups I and II, respectively. The mean estimated blood loss was 190 mL and 280 mL in groups I and II, respectively (P = 0.019). Three patients in group II developed chronic postcraniotomy headache compared to none in group I. Cosmetic outcome was excellent in group I while 4 patients in group II developed disfiguring depression at lateral sphenoid wing and anterior temple. In group I 17 out of 21 became seizure-free at one-year followup. Conclusion. Minicraniotomy through a linear skin incision is a sufficient surgical approach for effective standard temporal lobectomy and it has an excellent cosmetic outcome.

Lateral orbital wall approach to the cavernous sinus

Lesions of the cavernous sinus remain a technical challenge. The most common surgical approaches involve some variation of the standard frontotemporal craniotomy. Here, the authors describe a surgical approach to access the cavernous sinus that involves the removal of the lateral orbital wall. To achieve exposure of the cavernous sinus, a lateral canthal incision is performed, and the lateral orbital rim and anterior lateral wall are removed, for later replacement at closure. The posterior lateral orbital wall is removed to the region of the superior and inferior orbital fissures. With reflection of the dural covering of the lateral cavernous sinus and removal of the anterior clinoid process, the cavernous sinus is exposed. Exposure and details of the procedure were derived from anatomical study in cadavers. After the approach, with removal of the anterior clinoid process, the entire cavernous sinus from the superior orbital fissure anteriorly to the Meckel cave posteriorly is exposed. More exposure to the lateral middle fossa, foramen spinosum, and petrous carotid artery is obtained by further removal of the lateral sphenoid wing. An illustrative case example for approaching a cavernous sinus meningioma is presented. The translateral orbital wall approach provides a simple, rapid approach for lesions with primary or secondary involvement of the cavernous sinus. Advantages of this simple, extradural approach include the lack of brain retraction and no interruption of the temporalis muscle.

Transient oculomotor nerve palsy after topical administration of intracisternal papaverine

Dear Editor, We present three patients who suffered aneurysmal subarachnoid hemorrhage with mean age of 48 years. Two patients had middle cerebral artery aneurysms and the third had an anterior communicating artery aneurysm. All three patients underwent a standard frontotemporal craniotomy for clipping of ruptured aneurysm. All three aneurysms were clipped without the need for temporary occlusion and, in no case, was dissection or direct visualization of the oculomotor nerve necessary to obtain proximal control. Local vasospasm was visually apparent in the exposed carotid circulation in all three cases; thus topical 3–5 cc of a 3% solution of papaverine was administered after surgical clipping was completed. Immediate postoperative exam in all three cases revealed isolated ipsilateral oculomotor nerve palsy. The patients had no other neurological deficits suggestive of a space-occupying lesion or raised intracranial pressure. An immediate postoperative CT head was performed (Fig. 1) that only revealed expected postoperative changes and some intracranial air. In all three patients, the deficit resolved completely within a 24-h period (range 3–24 hours). Further recovery was uneventful and all three of these patients were discharged home without focal neurological deficit. Papaverine is a natural heterocyclic nitrogen alkaloid found in opium. It is a commonly used vasodilator that acts directly on smooth muscle. Based on clinical and experimental data, topical application of papaverine for reversal of vasospasm was first advocated by Pool in 1958 [8, 9]. Since then, papaverine has been used by neurosurgeons topically when encountering intraoperative visual evidence of vasospasm [3, 10]. There have been isolated case reports of facial nerve palsies [2, 6, 7], auditory nerve palsy [1], and pupillary changes [3, 10]. Although it may be common knowledge, a review of literature did not yield any prior reports of transient oculomotor nerve palsy (TONP) after topical/intracisternal papaverine use. Transient oculomotor nerve palsy after surgical clipping for aneurysms occurs in 2.9% to 32% of cases depending on the location of the aneurysm. In many cases, the phenomenon has been attributed to traction, mechanical irritation, or transient loss of blood supply to the oculomotor nerve [4, 5]. In our cases, the TONP was seen in the absence of any of the known risk factors. No manipulation of or dissection around the oculomotor nerve was performed in our three cases. Since these cases were observed, we have introduced a practice change by diluting the 3% papaverine solution to 0.3% with normal saline. In our experience, such dilution leads to satisfactory reversal of arterial spasm while preventing the transient oculomotor nerve palsies. Mechanistic explanation of the mode of action of papaverine in causing TONP is unknown. Animal studies combined with in vitro analysis of the mechanisms of action of papaverine are needed to further elucidate this important effect. Further prospective studies are needed to P. Chittiboina :A. Nanda :B. Guthikonda (*) Department of Neurosurgery, LSUHSC Shreveport, P O Box 33932, Shreveport, LA 71130-3932, USA e-mail: bguthi@lsuhsc.edu

Sudden visual loss due to posterior ischemic optic neuropathy following craniotomy for a ruptured intracranial aneurysm

The authors report a rare case of acute ipsilateral blindness that occurred after a standard fronto-temporal craniotomy for aneurysm in supine position. Posterior ischemic optic neuropathy caused by external pressure on the ipsilateral eye, its differentials and subsequent medico-legal implications are discussed.

脳卒中の外科における合併症の予防と対策 運動誘発電位モニタリングを用いた脳動脈りゅう手術

We investigated the usefulness of motor evoked potential (MEP) for detecting the cerebral blood flow insufficiency (BFI) during aneurysm surgery. The study population consisted of 269 patients with intracranial aneurysms who underwent surgery via a standard frontotemporal craniotomy. After the dura mater had been opened, a grid electrode strip with 16 small electrodes was inserted subdurally into the hand motor cortex from the edge of the craniotomy. The hand motor cortex was stimulated by short train stimuli. The MEPs were recorded from the contralateral thenar muscles in all but 3 patients who had severe preoperative motor paresis. We evaluated intraoperative MEP findings, causes of MEP changes and motor outcomes in the 266 patients in whom MEPs could be recorded. Out of 232 patients whose MEP remained unchanged, one developed mild and transient hemiparesis, and the other 231 had no postoperative motor paresis. Thirty-two of the other 34 patients manifested transient MEP changes. The transient MEP changes were thought to be attributable to BFI of the cortical branches in 4 patients, of the perforating artery in 15, and of either the cortical branches or the perforating artery in 13 patients. Of these 32 patients, 24 did not show any postoperative motor paresis; transient motor paresis was recognized in the other 8. In 2 patients, MEP disappeared and did not recover. These patients developed severe hemiparesis, and a postoperative CT scan revealed a new low-density area in the corona radiata, putamen and internal capsule. The findings of this study suggest that the monitoring method introduced here is safe and reliable for detecting intraoperative BFI in both the perforating artery and cortical branches. MEP monitoring is useful in preventing postoperative motor paresis in aneurysm surgery.

Are flash-evoked visual potentials useful for intraoperative monitoring of visual pathway function?

Flash-evoked visual potentials (VEPs) recorded from the scalp were used in a series of 35 patients with tumors along the visual pathway: 3 orbital tumors, 25 perisellar tumors, 4 intraventricular tumors, and 3 occipital lesions. Preoperatively, various combinations of impaired visual fields and visual acuity were observed in over 90% of the patients. A postoperative decrease in visual function was observed in 3 cases. Of the 25 perisellar lesions, 13 were operated through a standard frontotemporal craniotomy and 12 were operated through a transnasal-transsphenoidal approach. VEPs were highly susceptible to volatile anesthetics, and there was a significant incidence of spontaneous latency increases and amplitude decreases in a large number of patients. There was an unacceptably high number of cases with significant VEP alteration occurring without concomitant visual function change. During trepanation or the transnasal approach, a reversible potential loss was observed in 11 patients, a profoundly altered wave form was seen in 8 cases, and a loss of single peaks was observed in 15 patients. During dissection of the tumor, a reversible potential loss or a potential with unidentifiable peaks was found in 25 cases; however, the VEPs recovered during closure or in the recovery room. There was no correlation between intraoperative VEP changes and the postoperative changes in visual function. In only 1 patient with an insignificant postoperative decrease in visual acuity from 0.4 to 0.3 was there a concomitant intraoperative potential loss. The major conclusion of our findings is that light-emitting diode flash-evoked VEPs demonstrate intraoperative changes that appear too early and too prominently to be caused solely by manipulation of the optic pathways.(ABSTRACT TRUNCATED AT 250 WORDS)