Applications of supraorbital keyhole craniotomy in pediatric cranial trauma: illustrative series of two cases and systematic literature review.

Minimally invasive (MIS) approaches to neurosurgical diseases continue to increase in popularity due to their association with decreased infection risk, shorter recovery time, and improved cosmesis. Cosmesis and lower morbidity are especially important for pediatric patients. The supraorbital keyhole craniotomy (SOKC) is one MIS approach shown to be effective for both neoplastic and vascular pathologies in pediatric patients. However, it is limited data on its use in pediatric trauma patients. Two cases employing SOKC in pediatric trauma patients are presented here along with a systematic review of the literature. We queried PubMed, Scopus, and Web of Science databases from inception to August 2022 using the Boolean search term: (supraorbital OR eyebrow OR transeyebrow OR suprabrow OR superciliary OR supraciliary) AND (craniotomy OR approach OR keyhole OR procedure) AND (pediatric OR children OR child OR young) AND "trauma". Studies that discussed the use of an SOKC in a pediatric patient having sustained trauma to the frontal calvarium and/or anterior fossa/sellar region of the skull base were included. Details were extracted on patient demographics, trauma etiology, endoscope use, and surgical and cosmetic outcomes. We identified 89 unique studies, of which four met inclusion criteria. Thirteen total cases were represented. Age and sex were reported for 12 patients, 25% of whom were male; the mean age was 7.5 years (range: 3-16). Pathologies included acute epidural hematoma (9), orbital roof fracture with dural tear (1), blowout fracture of the medial wall of the frontal sinus with supraorbital rim fracture (1), and compound skull fracture (1). Twelve patients were treated with a conventional operating microscope, while one underwent endoscope-assisted surgery. Only one significant complication (recurrent epidural hematoma) was reported. There were no reported cosmetic complications. The MIS SOKC approach is a reasonable option for select anterior skull base trauma in the pediatric population. This approach has been used previously for successful frontal epidural hematoma evacuation, which is often treated by a large craniotomy. Further study is merited.

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.

Eyebrow supraorbital keyhole craniotomy for olfactory groove meningiomas with endoscope assistance: case series and systematic review of extent of resection, quantification of postoperative frontal lobe injury, anosmia, and recurrence.

BACKGROUND: Olfactory groove meningiomas (OGMs) are commonly treated with open craniotomy. Endonasal approaches have also been described. OBJECTIVE: To present clinical and radiographic outcomes for the minimally invasive eyebrow incision supraorbital keyhole approach with endoscopic assistance for OGMs. METHODS: We performed a retrospective single-center cohort study and a systematic literature review. RESULTS: Fifteen patients were identified, all with Grade I meningiomas. Radiographic gross total resection of enhancing tumor was achieved in all patients. Mean frontal lobe fluid-attenuated inversion recovery volume decreased from 11.1 ± 18.3 cm3 preoperatively to 9.9 ± 11.4 cm3 immediately postoperatively, and there was minimal new restricted diffusion (3.2 ± 2.2 cm3; max 7.5 cm3). Median length of stay was 3 days (range 2-8). Vision was improved in 4 (80%) and stable in 1 (20%) of 5 patients with a preoperative deficit. New postoperative anosmia occurred in 3 (23%) of 13 patients with any preoperative olfaction. All patients were satisfied with their cosmetic result at 3 months. After a median follow-up of 32.2 months, there were 2 (13.3%) asymptomatic radiographic recurrences, 1 treated with radiosurgery and the other with endoscopic endonasal approach (EEA). No patients required further craniotomy. Systematic review revealed the present series to be the largest to date reporting disaggregated outcomes for the eyebrow approach to OGM. CONCLUSION: The eyebrow incision supraorbital keyhole craniotomy with endoscopic assistance is a safe and effective approach to OGM with tumor control rates similar to more invasive open approaches and better than the endonasal approach. Rates of frontal lobe injury, CSF leak and anosmia are comparatively low.

[Bilateral supraorbital keyhole approach in surgery of multiple cerebral aneurysms: a case report and literature review]. / Bilateral'nyi supraorbital'nyi keyhole-dostup v khirurgii mnozhestvennykh anevrizm sosudov golovnogo mozga: sluchai iz praktiki i obzor literatury.

The choice of an approach in surgery of bilateral multiple aneurysms is a complex and topical issue. According to the literature data, the occurrence rate of multiple aneurysms varies between 6.5 and 33%. Many authors have proposed various modern microsurgical approaches to reduce the risk of adverse surgical outcomes. The need for surgery in several vascular territories requires a detailed assessment of the topographo-anatomical relationships upon choosing a surgical approach. An important issue is preliminary planning and personalization of an approach for a particular patient. MATERIAL AND METHODS: We report a case of clipping of mirror middle cerebral artery aneurysms using a minimally invasive bilateral approach. RESULTS: The presented case demonstrates successful clipping of middle cerebral artery aneurysms in different vascular territories using the bilateral supraorbital approach: a skin incision along the eyebrow followed by supraorbital keyhole craniotomy. Follow-up CT angiography in the postoperative period demonstrated elimination of aneurysms from the bloodstream. The cosmetic effect after the intervention was evaluated as excellent. CONCLUSION: The bilateral supraorbital approach in surgery of multiple mirror aneurysms may be recommended as an alternative to the contralateral or bilateral pterional approach. The bilateral supraorbital approach avoids additional traction of the frontal lobes, provides a focused personalized approach, and is a safe and effective approach with excellent cosmetic results.

Keyhole retrosigmoid approach for large vestibular schwannomas: strategies to improve outcomes.

OBJECTIVE There are numerous treatment strategies in the management for large vestibular schwannomas, including resection only, staged resections, resections followed by radiosurgery, and radiosurgery only. Recent evidence has pointed toward maximal resection as being the optimum strategy to prevent tumor recurrence; however, durable tumor control through aggressive resection has been shown to occur at the expense of facial nerve function and to risk other approach-related complications. Through a retrospective analysis of their single-institution series of keyhole neurosurgical approaches for large vestibular schwannomas, the authors aim to report and justify key techniques to maximize tumor resection and reduce surgical morbidity. METHODS A retrospective chart review was performed at the Centre for Minimally Invasive Neurosurgery. All patients who had undergone a keyhole retrosigmoid approach for the resection of large vestibular schwannomas, defined as having a tumor diameter of ≥ 3.0 cm, were included in this review. Patient demographics, preoperative cranial nerve status, perioperative data, and postoperative follow-up were obtained. A review of the literature for resections of large vestibular schwannomas was also performed. The authors' institutional data were compared with the historical data from the literature. RESULTS Between 2004 and 2017, 45 patients met the inclusion criteria for this retrospective chart review. When compared with findings in a historical cohort in the literature, the authors' minimally invasive, keyhole retrosigmoid technique for the resection of large vestibular schwannomas achieved higher rates of gross-total or near-total resection (100% vs 83%). Moreover, these results compare favorably with the literature in facial nerve preservation (House-Brackmann I-II) at follow-up after gross-total resections (81% vs 47%, p < 0.001) and near-total resections (88% vs 75%, p = 0.028). There were no approach-related complications in this series. CONCLUSIONS It is the experience of the senior author that complete or near-complete resection of large vestibular schwannomas can be successfully achieved via a keyhole approach. In this series of 45 large vestibular schwannomas, a greater extent of resection was achieved while demonstrating high rates of facial nerve preservation and low approach-related and postoperative complications compared with the literature.

Keyhole epilepsy surgery: corticoamygdalohippocampectomy for mesial temporal sclerosis.

Surgical approaches for medically refractory mesial temporal lobe epilepsy (MTLE) that previously have been reported include anterior temporal lobectomy (ATL), transcortical selective amygdalohippocampectomy, transsylvian amygdalohippocampectomy, and subtemporal amygdalohippocampectomy. Each approach has its advantages and potential pitfalls. The purpose of this report is to describe our technique of keyhole corticoamygdalohippocampectomy for patients with MTLE due to hippocampal sclerosis. Operations were performed through a 6-cm vertical linear incision and a low 2.5-cm keyhole craniotomy at the anterior squamous temporal bone. Resection of the anterior-most portions of the middle and inferior temporal gyri provided a cylinder-like corridor to the mesial temporal lobe. Identification of the temporal horn through a basal approach was followed by resection of the amygdala, uncus, and hippocampus-parahippocampal gyrus. This 9-year series included 683 patients with a minimum follow-up duration of 2 years. Surgery times were short (range, 1 h 35 min to 2 h 30 min). Only a small percentage of patients had complications (1.76%), and the rate of Engel Class I seizure-free outcome was 87%. No overt speech problems or visual field deficits were identified. Compared with the most popular conventional trans-middle temporal gyrus approach, this technique can make the operation easier, safer, and less traumatic to functional lateral neocortex.

Removal of a Penetrating Tree Branch in the Orbitofrontal Region-A Unique Application of an Orbitofrontal Craniotomy Through a Supraciliary Brow Approach.

BACKGROUND AND IMPORTANCE: Orbitocranial penetrating injury (OPI) is associated with neurological, infectious, and vascular sequalae. This report describes unique application of an orbitofrontal craniotomy through a supraciliary approach to remove a wooden stick penetrating through the orbit and frontal lobe, postoperative management, and antimicrobial therapy. CLINICAL PRESENTATION: A 51-yr-old male presented after a tree branch penetrated beneath his eye. He had no loss of consciousness and was neurologically intact with preserved vision and ocular motility. Computed tomography (CT) and CT angiogram revealed an isodense hollow cylindrical object penetrating though the left orbit and left frontal lobe. The object extended into the right lateral ventricle, abutting the left anterior cerebral artery. There was minimal intraventricular hemorrhage without arterial injury. The patient was treated with broad-spectrum antimicrobial coverage. The foreign body was removed and the dural defect repaired via an orbitofrontal craniotomy through a supraciliary eyebrow incision. He was treated with an extended course of antimicrobial therapy, and after 18 mo remained neurologically intact. CONCLUSION: OPI are a subset of penetrating brain injuries with potential for immediate injury to neurovascular structures and delayed complications including cerebrospinal fluid leak and infection. Treatment includes attempted complete removal of the foreign body and antimicrobial therapy. An orbitofrontal craniotomy through a supraciliary eyebrow incision may be effective in selected patients.

Keyhole Superior Interhemispheric Transfalcine Approach for Tuberculum Sellae Meningioma: Technical Nuances and Visual Outcomes.

BACKGROUND: Tuberculum sellae meningiomas are challenging tumors often compressing the optic apparatus and involving the optic canals. Traditional approaches provide wide exposure, but optic canal access can remain difficult. Endonasal approaches offer a less invasive option that allows access to the medial optic canals, but larger tumors can still be challenging along with a higher risk of postoperative spinal fluid leak. We present the use of a keyhole superior interhemispheric approach for tuberculum sellae meningioma resection. METHODS: Five patients with tuberculum sellae meningioma who underwent a keyhole superior interhemispheric approach were retrospectively reviewed. Preoperative tumor volumes, visual outcomes, extent of resection, pathologic grading, perioperative complications, recurrence rates, operative times, and hospital length of stays were analyzed. RESULTS: The average age of the patients was 68.6 ± 7.7 years old (range 57-78). Average tumor volume was 8 ± 1.8 cm3. All patients had a gross total resection. Three out of 5 patients had World Health Organization grade 1 meningioma, and the other 2 had World Health Organization grade 2 meningioma. There were no recurrences over an average follow-up of 18.6 months (range 1-44). On preoperative visual assessment, 9 out of 10 eyes (90%) had a deficit. Postoperative visual assessment found 9 out of 9 eyes with preoperative deficits had improvement (100%). There were no perioperative or postoperative complications. CONCLUSIONS: The keyhole superior interhemispheric approach provides a transcranial alternative that allows excellent exposure of the vasculature and both optic canals, resulting in good extents of resection and recovery of vision.

Endoscopic Endonasal and Supraorbital Removal of Tuberculum Sellae Meningiomas: Anatomic Guides and Operative Nuances for Keyhole Approach Selection.

BACKGROUND: With growing worldwide endoscopy experience, endonasal and supraorbital removal of tuberculum sellae meningiomas (TSM) has increased. OBJECTIVE: To describe anatomic factors for guiding approach selection and outcomes. METHODS: Retrospective analysis of patients undergoing endonasal or supraorbital TSM resection: approach criteria, clinical outcomes, acute magnetic resonance imaging (MRI) fluid-attenuated inversion-recovery (FLAIR)/T2 changes. RESULTS: From 2008 to 2020, 33 patients (mean age 55 ± 11 yr) were identified: 20 (61%) had endonasal and 13 (39%) supraorbital removal. Comparing endonasal and supraorbital approaches, mean tumor volume (3.7 ± 3.5 cm3 vs 7.7 ± 8.5 cm3, P = .07); percent tumor above planum (42% vs 65%, P = .02), and lateral tumor beyond supraclinoid internal carotid arteries (1.4 ± 2.0 mm vs 4.0 ± 3.2 mm, P = .006) were greater for supraorbital route. Sellar depth was greater for endonasal route tumors (12.2 ± 2.6 mm vs 9.3 ± 2.4 mm, P = .003). Endoscopy, used in 10/13(77%) supraorbital cases, was helpful in additional tumor removal in 4/10(40%). Gross total removal and mean volumetric tumor resection were 16/20(80%) and 97.5% by endonasal, and 5/13(39%) and 96% by supraorbital route. Vision improved in 12/17 (71%) endonasal, 6/8 (75%) supraorbital operations, and worsened in 1 (3%) supraorbital case. Endonasal approach with optic canal decompression increased over study period: 15/20 (75%) endonasal patients vs 1/13(8%) supraorbital (P < .001). Postoperative FLAIR/T2 MRI changes occurred in 2/12 supraorbital and 0/20 endonasal cases. CONCLUSION: In our experience, both endonasal and supraorbital routes are safe and effective for TSM removal. Greater tumor extension below planum and medial optic canal invasion favor endonasal route, while larger size and lateral extension favor supraorbital route. Given high frequency of TSM growth into optic canals and better access for medial optic canal tumor removal, endonasal route may be preferred for most TSMs.

Keyhole clipping of a low-lying basilar apex aneurysm without posterior clinoidectomy utilizing endoscopic indocyanine green video angiography.

BACKGROUND: Basilar apex (BX) aneurysms are surgically challenging due to their anatomic location, need to traverse neurovascular structures, and proximity to multiple perforator arteries. Surgical approaches often require extensive bone resection and neurovascular manipulation. Visualization of low-lying BX aneurysms is typically obscured by the posterior clinoid and upper clivus and poses a unique challenge. Subtemporal or anterolateral approaches with a posterior clinoidectomy are often required to achieve adequate exposure, though these maneuvers can add invasiveness, risk, and morbidity to the procedure. Endoscopes and, more recently, fluoroscopic angiography capable endoscopes offer the possibility of providing improved visualization with less exposure allowing for minimally invasive clipping. CASE DESCRIPTION: We present the case of a 42-year-old female with incidentally found 5 mm middle cerebral artery and 5 mm BX aneurysms. She underwent a minimally invasive supraorbital keyhole craniotomy for the clipping of both aneurysms. While the posterior clinoid obstructed the necessary visualization for the BX aneurysm, use of endoscopy and endoscopic fluoroscopic angiography allowed for safe and successful clipping without the need for a posterior clinoidectomy. CONCLUSION: This represents the first reported case of a BX aneurysm clipping through a minimally invasive keyhole craniotomy using endoscopic indocyanine green video angiography. Use of endoscopic indocyanine green angiography, combined with keyhole endoscopic approaches, allows for safe minimally invasive clipping of challenging posterior circulation aneurysms.

Minimally Invasive Repair of Tegmen Defects Through Keyhole Middle Fossa Approach to Reduce Hospitalization.

OBJECTIVE: The middle fossa craniotomy for tegmen defect repair provides wide access. This approach often requires temporal lobe manipulation, lumbar drain placement, and longer recovery. We describe a keyhole middle fossa approach with a simple titanium skull base repair that allows for wide access with no temporal lobe manipulation and does not require lumbar drain placement, which results in a dramatic reduction in hospital length of stay. METHODS: A retrospective review was performed on 14 consecutive patients with spontaneous cerebrospinal fluid (CSF) otorrhea. Each patient underwent a keyhole middle fossa approach followed by multilayer dural repair with titanium mesh "gull wing" skull base reconstruction. Postoperative measures included operative time, length of hospital stay, CSF leak recurrence, and surgical complications (seizures, hemorrhage, aphasia, infection). RESULTS: The average age of the patients was 60.7 ± 12.7 years old, and average body mass index was 32.8 ± 7.9 kg/m2. Nine of the patients were female. The average operative time was 103 ± 32.8 minutes. The average hospital length of stay was 1.4 days. There were no cases of postoperative CSF otorrhea, meningitis, aphasia, or seizures. There were no recurrences over a mean follow-up of 20.3 months (range: 5-48 months). CONCLUSIONS: A minimally invasive keyhole middle fossa approach with a multilayer dural reconstruction including titanium mesh "gull wing" skull base repair provides a quick, effective treatment for a broad spectrum of tegmen defects and meningoencephaloceles. This exposure and reconstruction technique do not require the use of a lumbar drain and result in minimal hospitalization.

Tuberculum Sellae Meningiomas in Pregnancy: 3 Cases Treated in the Second Trimester and Literature Review.

BACKGROUND: Tuberculum sella meningiomas typically present with progressive visual loss. It is also known that meningiomas can become symptomatic during pregnancy. Herein we report on 3 patients who presented with progressive visual decline during pregnancy, prompting urgent surgical removal of their meningiomas. CASE DESCRIPTIONS: From our prospectively collected brain tumor database, all women surgically treated for tuberculum sella meningioma since 2006 were retrospectively reviewed. Clinical presentation, surgical approach, perioperative management, and pathology of pregnant patients were reviewed and compared with those of the nonpregnant cohort. Of 43 women with newly diagnosed tuberculum sella meningioma, 3 (7%) presented in pregnancy with progressive visual loss, 1 in the late first trimester and 2 in the early second trimester. One woman pregnant with twins had a broad-based meningioma and underwent a supraorbital craniotomy and gross total tumor removal in her second trimester. Two women with singleton pregnancies both underwent endoscopic endonasal gross total tumor removal during their second trimesters. All 3 patients had visual recovery, 2 of which were complete, and all went on to have successful uncomplicated deliveries of their children and maintain normal pituitary gland function. CONCLUSIONS: Presentation of tuberculum sella meningioma during pregnancy is uncommon but not rare, accounting for 7% of women in our series. Ideally, surgery is performed in the second trimester, ensuring fetal safety while restoring maternal vision and maintaining pituitary gland function are essential. Depending on tumor size and sellar anatomy, endoscopic endonasal or supraorbital keyhole craniotomy approaches are both viable options.

Nasal dermoid cysts with intracranial extension: avoiding coronal incision through midline exposure and nasal bone osteotomy.

OBJECTIVE: Up to 10% of midline nasal dermoid cysts have intracranial extension. Previous techniques of excision include frontal and frontonasal craniotomies via a coronal approach, combined with a direct cutaneous excision of the dermoid cyst. While the coronal incision allows for wide visualization, it carries significant risks of transfusion, blood loss, and scarring. The authors present an alternative technique in which access is gained through a midline extension of the dermoid cyst excision that provides direct access for a keyhole frontal craniotomy. METHODS: The authors utilize a nasal bone osteotomy, pericranial flap, and keyhole-type craniotomy performed through a nasal midline incision for the treatment of nasal dermoid cysts with intracranial extension. They performed a retrospective chart review of all patients with nasal dermoid cysts treated at the Ann & Robert H. Lurie Children's Hospital of Chicago from 2009 to 2017. Patient demographic data, operative data, and in- and outpatient complication data were collected. RESULTS: In 10 patients with cyst extension near or into the intracranial cavity (7 with true intracranial extension), the nasal osteotomy technique was performed. The mean blood loss was 13 ml, with a 0% transfusion rate. The mean length of inpatient stay was 1 day. A durotomy was made and repaired as part of the dermoid cyst dissection in 3 patients. One patient underwent intraoperative placement of a lumbar drain. The mean operative time was 228 minutes. There were no intraoperative or postoperative complications, including the need for a reoperation. No patients had any long-term complications, and no patients have had dermoid cyst recurrence. The appearance of the scar was acceptable in all cases. CONCLUSIONS: The midline approach to nasal dermoid cysts with intracranial extension is safe and results in limited blood loss, short operative times, and short lengths of inpatient hospital stay. This is a viable technique for the treatment of this challenging pathology.

Supracerebellar Infratentorial Approach for Complex Thalamic Cavernous Malformation: 2-Dimensional Operative Video.

Key points for the approach include the use of a supracerebellar infratentorial craniotomy, dynamic and gravity retraction, lighted bipolar forceps and suction, and stereotactic navigation. This patient has a large cavernous malformation extending from the midbrain to the thalamus in craniocaudal extent. The cavernous malformation extends to the midbrain surface along the interface with the ambient cistern, making it appropriate for the supracerebellar infratentorial approach. By cutting the tentorium access to the superior extension becomes feasible. The cavernous malformation is excised in a piecemeal manner utilizing a CO2 laser. Because removal of the large mass allowed the partial collapse of the cavity, a small segment of the cavernous malformation obscured by the collapse is retained cranially along the foramen of Monro. This situation required a return to the operating room for complete excision. The patient tolerated both procedures well and remained at her neurological baseline postoperatively. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary. The surgical video has been used with permission from the Barrow Neurological Institute.

Syringe Port: A Convenient, Safe, and Cost-Effective Tubular Retractor for Transportal Removal of Deep-Seated Lesions of the Brain.

OBJECTIVE: Minimally invasive transportal resection of deep intracranial lesions has become a widely accepted surgical technique. Many disposable, mountable port systems are available in the market for this purpose, like the ViewSite Brain Access System. The objective of this study was to find a cost-effective substitute for these systems. METHODS: Deep-seated brain lesions were treated with a port system made from disposable syringes. The syringe port could be inserted through minicraniotomies placed and planned with navigation. All deep-seated lesions like ventricular tumours, colloid cysts, deep-seated gliomas, and basal ganglia hemorrhages were treated with this syringe port system and evaluated for safety, operative site hematomas, and blood loss. RESULTS: 62 patients were operated on during the study period from January 2015 to July 2017, using this innovative syringe port system for deep-seated lesions of the brain. No operative site hematoma or contusions were seen along the port entry site and tract. CONCLUSIONS: Syringe port is a cost-effective and safe alternative to the costly disposable brain port systems, especially for neurosurgical setups in developing countries for minimally invasive transportal resection of deep brain lesions.

Supraorbital vs Endo-Orbital Routes to the Lateral Skull Base: A Quantitative and Qualitative Anatomic Study.

BACKGROUND: Various extensions of the supraorbital approach reach the lateral and parasellar middle cranial fossa regions by removing the orbital rim and greater/lesser sphenoid wings. Recent proposals of a purely endoscopic ventral transorbital pathway to these regions heighten the need to compare these surgical windows. OBJECTIVE: To detail the lateral and parasellar middle cranial fossa regions and quantify exposures by 2 surgical windows (transcranial and transorbital) through anatomic study. METHODS: In 5 cadaveric specimens (10 sides), dissections consisted of 3 stages: stage 1 began with the supraorbital approach via the eyebrow; stage 2, endo-orbital approach via the superior eyelid, continued with removal of lesser and greater sphenoid wings; and stage 3, extended supraorbital, re-evaluated the gains of stage 2 from the perspective of stage 1. Operative working areas were quantified in Sylvian, anterolateral temporal, and parasellar regions; bone removal volumes were measured at each stage (nonpaired Student t-test). RESULTS: Visualization into the anterolateral temporal and Sylvian areas, though varied in perspective, were comparable with either eyelid or transcranial routes. Compared with transcranial views through a supraorbital window, the eyelid approach significantly increased exposure in the parasellar region with wider angle of attack (P < .01) and achieved comparable bone removal volumes. CONCLUSION: Stage 2's unique anatomic view of the lateral and parasellar middle cranial fossa regions paves the way for possible surgical application to select pathologies typically treated via transcranial approaches. Disadvantages may be the surgeon's unfamiliarity with the anatomy of this purely endoscopic, ventral route and difficulties of dural and orbital repair.

Endoscope-assisted repair of CSF otorrhea and temporal lobe encephaloceles via keyhole craniotomy.

OBJECTIVE Temporal lobe encephaloceles and cerebrospinal fluid otorrhea from temporal bone defects that involve the tegmen tympani and mastoideum are generally repaired using middle fossa craniotomy, mastoidectomy, or combined approaches. Standard middle fossa craniotomy exposes patients to dural retraction, which can lead to postoperative neurological complications. Endoscopic and minimally invasive techniques have been used in other surgeries to minimize brain retraction, and so these methods were applied to repair the lateral skull base. The goal of this study was to determine if the use of endoscopic visualization through a middle fossa keyhole craniotomy could effectively repair tegmen defects. METHODS The authors conducted a retrospective review of 6 cases of endoscope-assisted middle fossa repairs of tegmen dehiscences at a tertiary care medical center within an 18-month period. RESULTS All cases were successfully treated using a keyhole craniotomy with endoscopic visualization and minimal retraction. Surgical times did not increase. There were no major postoperative complications, recurrences of encephaloceles, or cerebrospinal fluid otorrhea in these patients. CONCLUSIONS Endoscopic visualization allows for smaller incisions and craniotomies and less risk of brain retraction injury without compromising repair integrity during temporal encephalocele and tegmen repairs.

Minimally Invasive Middle Fossa Keyhole Craniectomy for Repair of Superior Semicircular Canal Dehiscence.

BACKGROUND: Superior semicircular canal dehiscence (SSCD) presents with varying degrees of auditory and vestibular dysfunction. The condition is confirmed on high-resolution computed tomography (CT) imaging, and symptoms are often improved by surgical repair. Although a classic middle fossa craniotomy has been used with good results, recent advances in technique have allowed for modification of the traditional approach into a smaller skin incision and a minimally invasive middle fossa keyhole craniectomy roughly 1.7 cm in diameter. OBJECTIVE: To delineate this novel approach and describe the technique for accurate localization of the dehiscence using preoperative measurements and intraoperative image guidance, thereby minimizing the need for a larger skin incision and craniotomy. METHODS: Patients were independently diagnosed with SSCD by the senior authors. Once relevant imaging was acquired, the novel keyhole technique was performed. Patients' vestibular and auditory symptoms before and after the procedure were assessed. Outcomes from a series of patients treated with this keyhole approach were tabulated and reported. RESULTS: Twelve cases from 11 patients were included in this series. Auditory symptoms had high rates of resolution with pulsatile tinnitus, internal amplification of sounds, and autophony being resolved in a majority of cases. Only 2 cases reported hearing decline. Sound/pressure induced vertigo and disequilibrium also demonstrated high rates of resolution. No complications were reported. CONCLUSION: The minimally invasive middle fossa keyhole craniectomy is a novel approach for the repair of SSCD. This approach may contribute to resolved auditory and vestibular symptoms with low morbidity and quick recovery.

Supraorbital Keyhole Craniotomy for Basilar Artery Aneurysms: Accounting for the "Cliff" Effect.

BACKGROUND: Treatment of basilar artery aneurysms is challenging. While endovascular techniques have dominated, there still remain circumstances where open surgical clipping is required or preferred. Minimally invasive "keyhole" approaches are being used more frequently to provide the durability of surgical clipping with a lower morbidity profile; however, careful patient selection is required. The supraorbital "keyhole" approach has been described for the treatment of basilar artery aneurysms, but careful assessment of the basilar exposure is necessary to ensure proper visualization of the aneurysm and ability to obtain proximal vascular control. Various methods of estimating the basilar artery exposure in this approach have been described, including the anterior skull base line and the posterior clinoid line, but both are unreliable and inaccurate. OBJECTIVE: To propose a new method, the orbital roof-dorsum line, to simply and accurately predict the basilar artery exposure. METHODS: CT angiograms for 20 consecutive unique patients were analyzed to obtain the anterior skull base line, posterior clinoid line, and the orbital roof-dorsum line. CT angiograms were then loaded onto a Stealth neuronavigation system (Medtronic, Minneapolis, Minnesota) to obtain "true" visualization lengths. A case illustration is presented. RESULTS: Pairwise comparison tests demonstrated that both the anterior skull base and the posterior clinoid estimation lines differed significantly from the "true" value ( P < .0001). Our orbital roof-dorsum estimation provided results that accurately predicted the "true" value ( P = .71). CONCLUSION: The orbital roof-dorsum line provides a simple and reliable method of estimating basilar artery exposure and should be used whenever considering patients for surgical clipping by this approach.

Engaging in a Keyhole Concept for the Management of Ruptured and Unruptured Aneurysms.

OBJECTIVE: Many new endovascular devices have been used under the guidance of the International Subarachnoid Aneurysm Trial. Clipping still offers higher occlusion rates, and its technique continues to evolve, resulting in smaller exposures and reduced manipulation to brain tissue. We sought to evaluate the routine use of the minisphenoidal approach to manage intracranial aneurysms in a high-volume institution. METHODS: We retrospectively reviewed our database of patients with aneurysm from October 2013 to May 2016. Data were originally collected prospectively. The minisphenoidal approach has been progressively replacing the pterional approach for managing aneurysms in our department. Occlusion rates for ruptured and unruptured aneurysms were analyzed using late follow-up angiograms. Functional outcome assessment and the impact on quality of life were also measured. RESULTS: We performed 124 minisphenoidal craniotomies in 117 patients to clip 147 aneurysms. Patient mean age was 53.9 years. Seventy patients (59.8%) presented with subarachnoid hemorrhage. Middle cerebral artery aneurysms represented 48% of the total number of aneurysms; posterior communicating artery aneurysms represented 24%. The minisphenoidal craniotomy was helpful in managing superior cerebellar artery aneurysms and 1 ruptured orbitofrontal artery aneurysm. We achieved an occlusion rate of 97.8%, with a mean follow-up of 13.2 months. Favorable outcomes were achieved for 79% of patients with subarachnoid hemorrhage and for 98% of unruptured patients. CONCLUSIONS: Evolution of endovascular techniques has paved the way for minimizing surgical exposures. Routine use of the minisphenoidal approach for managing ruptured, unruptured, and previously coiled aneurysms is safe and provides adequate exposure with robust occlusion rates.