Interrupted time-series analysis: studying trends in neurosurgery.

OBJECT Neurosurgery studies traditionally have evaluated the effects of interventions on health care outcomes by studying overall changes in measured outcomes over time. Yet, this type of linear analysis is limited due to lack of consideration of the trend's effects both pre- and postintervention and the potential for confounding influences. The aim of this study was to illustrate interrupted time-series analysis (ITSA) as applied to an example in the neurosurgical literature and highlight ITSA's potential for future applications. METHODS The methods used in previous neurosurgical studies were analyzed and then compared with the methodology of ITSA. RESULTS The ITSA method was identified in the neurosurgical literature as an important technique for isolating the effect of an intervention (such as a policy change or a quality and safety initiative) on a health outcome independent of other factors driving trends in the outcome. The authors determined that ITSA allows for analysis of the intervention's immediate impact on outcome level and on subsequent trends and enables a more careful measure of the causal effects of interventions on health care outcomes. CONCLUSIONS ITSA represents a significant improvement over traditional observational study designs in quantifying the impact of an intervention. ITSA is a useful statistical procedure to understand, consider, and implement as the field of neurosurgery evolves in sophistication in big-data analytics, economics, and health services research.

Comparison of open and minimally invasive surgery for intradural-extramedullary spine tumors.

OBJECT Patients with symptomatic intradural-extramedullary (ID-EM) tumors may be successfully treated with resection of the lesion and decompression of associated neural structures. Studies of patients undergoing open resection of these tumors have reported high rates of gross-total resection (GTR) with minimal long-term neurological deficit. Case reports and small case series have suggested that these patients may be successfully treated with minimally invasive surgery (MIS). These studies have been limited by small patient populations. Moreover, there are no studies directly comparing perioperative outcomes between patients treated with open resection and MIS. The objective of this study was to compare perioperative outcomes in patients with ID-EM tumors treated using open resection or MIS. METHODS A retrospective review was performed using data collected from 45 consecutive patients treated by open resection or MIS for ID-EM spine tumors. These patients were treated over a 9-year period between April 2003 and October 2012 at Northwestern University and the University of Chicago. Statistical analysis was performed to compare perioperative outcomes between the two groups. RESULTS Of the 45 patients in the study, 27 were treated with the MIS approach and 18 were treated with the open approach. Operative time was similar between the two groups: 256.3 minutes in the MIS group versus 241.1 minutes in the open group (p = 0.55). Estimated blood loss was significantly lower in the MIS group (133.7 ml) compared with the open group (558.8 ml) (p < 0.01). A GTR was achieved in 94.4% of the open cases and 92.6% of the MIS cases (p = 0.81). The mean hospital stay was significantly shorter in the MIS group (3.9 days) compared with the open group (6.1 days) (p < 0.01). There was no significant difference between the complication rates (p = 0.32) and reoperation rates (p = 0.33) between the two groups. Multivariate analysis demonstrated an increased rate of complications in cervical spine tumors (OR 15, p = 0.05). CONCLUSIONS Thoracolumbar ID-EM tumors may be safely and effectively treated with either the open approach or an MIS approach, with an equivalent rate of GTR, perioperative complication rate, and operative time. Patients treated with an MIS approach may benefit from a decrease in operative blood loss and shorter hospital stays.

Endoscopic Transsphenoidal Resection of Cystic Third Ventricular Craniopharyngioma with Cystocisternal Fenestration.

Cystic craniopharyngiomas of the third ventricle can be challenging to treat because complete resection of the cyst wall can be associated with hypothalamic dysfunction and minimal rostral displacement of the optic chiasm leads to a small endonasal operative corridor. Various methods to overcome the frequent recurrences have been described, such as intracystic bleomycin or catheter placement, with mixed results.1-12 In Video 1, we describe a simple cystocisternal fenestration technique with preservation of the rostral cyst wall via an endoscopic endonasal approach where the solid portion of the tumor is resected, and the inferior wall of the cyst is opened into the prepontine cistern and the superior wall of the cyst and adjacent third ventricle are preserved. This allows for ventricular pressure to collapse the cyst cavity in the postoperative period. In select patients where safe complete resection of a cystic craniopharyngioma is prohibitive, this may provide a durable treatment and can be performed through a small endonasal corridor below a nondisplaced optic chiasm.

Thrombolysis for intraventricular hemorrhage.

Intraventricular hemorrhage is a frequent complication of intracerebral hemorrhage and is independently associated with significant morbidity and mortality. Intraventricular fibrinolytic therapy is used with increasing frequency to accelerate clot clearance. We review the recent evidence and discuss the therapeutic benefits as well as the current concerns and limitations of fibrinolytic use in this setting.

Microendoscopic decompression for cervical spondylotic myelopathy.

OBJECT: Cervical spondylotic myelopathy (CSM) is a common cervical degenerative disease that affects the elderly population. Spinal cord decompression is achieved through various anterior and posterior approaches including anterior cervical decompression and fusion, laminectomy, laminoplasty, and combined approaches. The authors describe another option, minimally invasive endoscopically assisted decompression of stenosis (MEDS), which obviates the need for muscle dissection and disruption of the posterior tension band, a cause of postlaminectomy kyphosis. METHODS: The authors conducted a retrospective study of 10 patients with CSM who underwent MEDS from January 2002 through July 2012. Data were collected on demographics, preoperative and postoperative Nurick scores, postoperative Odom scores, and preoperative and postoperative Cobb angles. RESULTS: The mean patient age (± SD) was 67 ± 7.7 years; 8 patients were male. The average number of disc levels operated on was 2.2 (range 1-4). The mean Nurick score was 1.6 ± 0.7 preoperatively and improved to 0.3 ± 0.7 postoperatively (p < 0.0005). The postoperative Odom scores indicated excellent outcomes for 4 patients, good for 3, fair for 2, and poor for 1. The average preoperative focal Cobb angle at the disc levels operated on was -0.43º ± 1.9º. The average Cobb angle at the last follow-up visit was 0.25° ± 1.6° (p = 0.6). The average follow-up time was 18.9 ± 32.1 months. There were no intraoperative or postoperative complications. CONCLUSIONS: For selected patients with CSM, whose pathologic changes are primarily posterior and who have acceptable preoperative lordosis, MEDS is an alternative to open laminectomy and laminoplasty.

Keyhole retrosigmoid approach without watertight dural closure - Evaluation of a minimalistic approach.

BACKGROUND: The retrosigmoid craniotomy is a versatile surgical approach to the cerebellopontine angle though cerebrospinal fluid leak remains a concern, with a reported prevalence of 0-22 %. A host of closure materials and strategies have been proposed to achieve a watertight dural closure to varying degrees of success. We review our series of keyhole retrosigmoid craniotomies and describe our simple, standardized method of closure without watertight dural closure. METHODS: A retrospective review of all retrosigmoid craniotomies performed by the senior author was completed. Closure was achieved by placing an oversized piece of gelatin in the subdural space. The dura is grossly approximated. An oversized sheet of collagen matrix is placed as an overlay followed by gelatin sponge in the craniectomy defect held in place with titanium mesh. The superficial layers are approximated. The skin is closed with a running sub-cuticular suture followed by skin glue. Patient demographics, cerebrospinal fluid leak risk factors, and surgical outcomes were determined. RESULTS: A total of 114 patients were included. There was one case (0.9 %) of CSF leak, which resolved with placement of a lumbar drain for 5 days. The patient had one defined risk factor (morbid obesity, BMI 41.0 kg/m2). CONCLUSIONS: Obtaining a watertight dural layer closure has been the generally accepted strategy in preventing CSF leaks in a traditional retrosigmoid approach. In keyhole retrosigmoid approaches it may not be necessary by utilizing a simple gelfoam bolstered collagen matrix onlay technique potentially improving outcome measures including operative time.

Split-Thickness Decompression in the Management of Intracranial Pressure.

Surgical management of elevated intracranial pressures due to stroke or traumatic brain injury has classically been through decompressive craniectomy (DC). There is significant morbidity associated with DC including subdural hygromas, syndrome of the trephined, and the need for subsequent cranioplasty. Alternative techniques including the hinged and floating craniotomy have shown promise though can still suffer from complications associated with an unsecured bone flap. We report a case in which a patient who presented with an acute subdural hematoma and associated midline shift that was successfully treated with decompression via thinning and re-securing of the bone flap in a "split-thickness decompression."

Keyhole Superior Interhemispheric Approach to Midline Meningiomas of the Far Frontal Region of the Anterior Skull Base: Cadaveric Study and Illustrative Cases.

OBJECTIVE: Unique challenges can present in the treatment of small to mid-sized meningiomas that arise from the region of the anterior most aspect of the falx cerebri including its junction with the anterior skull base, what we call the far frontal region. Although this region of the anterior skull base is considered in the surgical approach of olfactory groove meningiomas invading this space, important differences exist between these tumors and those of the far frontal region. METHODS: Toward refining surgical selection, our cadaveric study details a minimally invasive keyhole superior interhemispheric approach to the far frontal region and 2 illustrative cases show the feasibility of this approach. RESULTS: Our cadaveric study defines 5 steps of the approach from the incision, craniectomy, dural opening, approaching the skull base and ipsilateral exposure, and finally falcine resection and bilateral skull base exposure. Two illustrative cases with the approach confirmed visualization of the full extent of tumor and gross total resection with preservation of the unaffected olfactory bulb. CONCLUSIONS: To the best of our knowledge, our anatomic study is distinctively unique in quantifying the working distance of the keyhole superior interhemispheric exposure and refining visualization of the far frontal region. We discuss these benefits and limitations (i.e., substantial involvement of tumor beyond midline) and differences with large meningiomas of the olfactory groove and far frontal region with significant posterior or lateral extension for which conventional exposures are appropriate.

Osimertinib-induced rapid regression of large metastatic tumor to the pituitary in a patient with lung adenocarcinoma.

BACKGROUND: Metastatic nonsmall cell lung cancer (NSCLC) to the pituitary (NSCLC-PitM) is rare and often presents with visual field deficits. Surgical resection for the decompression of the optic apparatus has been the treatment of choice in such cases. Osimertinib is a third-generation tyrosine kinase inhibitor (TKI) approved for the treatment of patients with NSCLC with an epithelial growth factor receptor (EGFR) mutation though its role in the treatment of NSCLC-PitM that remains unclear. We present a case of NSCLC-PitM with optic chiasm compression and visual deficits that were successfully treated with osimertinib alone without surgical intervention. CASE DESCRIPTION: A 43-year-old male presented with pleuritic chest pain, fatigue, and visual deficits found to have NSCLC and a sellar mass with suprasellar extension and optic chiasm compression. Visual field testing demonstrated associated visual field deficits. Molecular testing was positive for EGFR exon 19 deletion. The patient was started on osimertinib with complete resolution of pituitary lesion and visual deficits at 4 weeks. CONCLUSION: Osimertinib is a third-generation EGFR-TKI that has demonstrated promising results among patients with metastatic EGFR-mutated NSCLC. While surgery is the mainstay of treatment in patients with a sellar mass, optic compression, and visual deficits, those with EGFR-mutated NSCLC-PitM may benefit from early initiation of such systemic therapies, rather than surgical intervention, with good ophthalmologic results.

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.

Minimally Invasive Lateral Orbital Wall Approach for Sphenocavernous Meningioma Resection with Endoscope Assistance.

Sphenocavernous meningiomas are technically challenging tumors that, in addition to cavernous sinus neurovascular involvement, frequently affect the optic nerve and carotid artery. The surgical goal generally consists of complete resection of the extracavernous portion of the tumor, whereas the cavernous sinus tumor can be treated with postoperative radiation if necessary. Traditional techniques include the pterional or orbitozygomatic approach that requires substantial soft tissue, scalp, and temporalis muscle mobilization along with temporal and frontal lobe manipulation. A keyhole craniotomy performed through a lateral orbitotomy provides a minimally invasive option with excellent tumor exposure that obviates the need for soft tissue trauma or brain manipulation. Use of an endoscope can provide further visualization for more expansive tumors. This Video 1 presentation demonstrates a case of an 84-year-old woman with a growing sphenocavernous meningioma and abducens palsy who underwent a minimally invasive lateral orbital wall approach for resection of the extracavernous tumor. There were no intra- or perioperative complications, and the patient was discharged home on postoperative day 1. This technique is a useful addition to the armamentarium of surgeons who treat these complex tumors.

Successful treatment of superior sagittal sinus thrombosis after translabyrinthine resection of metastatic neuroendocrine tumor: A case report and review of literature.

BACKGROUND: Postoperative cerebral venous sinus thrombosis (pCVST) after resection of cerebellopontine angle and posterior fossa tumor resections occur almost exclusively in the lateral venous sinuses and are generally asymptomatic. Thrombus extension and involvement of the superior sagittal sinus (SSS) - a serious and potentially devastating complication - are rarely described and, as such, successful treatment for which is still poorly understood. We report a case of pCVST involving the SSS after translabyrinthine approach for resection of a metastatic neuroendocrine tumor (NET), and the first that was successfully treated with anticoagulation therapy. CASE DESCRIPTION: A 40-year-old man presented with headaches, diminished right-sided hearing, and ataxia was found to have a large right-sided cerebellopontine angle (CPA) lesion with extra-axial and possible intraparenchymal invasion. A retrosigmoid craniotomy for debulking and diagnosis was undertaken. Postoperative imaging revealed patent venous sinuses. Pathology confirmed NET. Further imaging revealed a likely pancreatic primary lesion. The patient then underwent subsequent translabyrinthine approach for definitive surgical resection. Postoperative imaging again revealed patent venous sinuses. The patient subsequently developed headaches on postoperative day 10 and was found to have pCVST involving the ipsilateral internal jugular to the SSS. The patient was started on therapeutic heparin with significant improvement in pCVST and symptoms. CONCLUSION: Extensive pCVST involving the SSS after CPA and posterior fossa tumor resections is extremely rare. Initial management with anticoagulation can yield promising results and should be initiated early in the clinical course unless otherwise contraindicated.

Minimally Invasive Tubular Approach for Occipital Condylar Biopsy and Resection: Case Report and Review of Literature.

BACKGROUND: Patients with isolated occipital condyle lesions concerning for metastases rarely undergo surgical biopsies and are more commonly treated with empirical radiation with or without chemotherapy. This is likely related to the morbidity associated with open condylar approaches and the importance of surrounding structures. We present a minimally invasive technique to approach the occipital condyle using a tubular dilating retractor system. CASE DESCRIPTION: A 38-year-old woman with medical history of breast cancer presented with a 2-month history of headache localizing to the right occipital area and right tongue deviation. Magnetic resonance imaging revealed a heterogeneously enhancing mass within the right occipital condyle. The patient was brought into the operating room and placed in prone position. A 2-cm paramedian incision was made on the right approximately 2.5 cm off midline at the level of C1. Sequential dilation using a tubular retractor system was performed under fluoroscopic guidance. Once the condylar cortex was identified and entered, the tumor was immediately visualized and resected. Operative time was 65 minutes and estimated blood loss was 5 mL. The patient was discharged to home on postoperative day 1. CONCLUSIONS: This report, to our knowledge, presents the first case of a minimally invasive tubular retractor system-based approach for biopsy and resection of an occipital condylar metastasis causing occipital condyle syndrome. This approach allows for tissue diagnosis to precisely dictate medical management and minimizes the morbidity associated with traditional open surgical approaches.

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.

Sellar trough technique for endoscopic endonasal transclival repair.

BACKGROUND: Endoscopic endonasal transclival approaches provide direct access to the ventral skull base allowing the treating of clival and paraclival pathology without the manipulation of the brain or neurovascular structures. Postoperative spinal fluid leak, however, remains a challenge and various techniques have been described to reconstruct the operative defect. The "gasket seal" has been well-described, but has anatomic challenges when applied to clival defects. We describe a modification of this technique for use in endonasal transclival approaches. METHODS: Two patients who underwent an endoscopic endonasal transclival approach for tumor resection with an intraoperative spinal fluid leak underwent a modified "gasket seal" closure technique for skull base reconstruction. RESULTS: A 71-year-old woman with a petroclival meningioma and a 22 year old with a clival chordoma underwent endoscopic endonasal transclival resection with the modified repair. No new postoperative deficits occurred and no postoperative spinal fluid leak was seen with a follow-up of 17 and 23 months, respectively. CONCLUSION: We describe the successful use of a simple, low risk, and technique modification of the "gasket seal" technique adapted to the clivus that allows for hard reconstruction and facilitates placement of the nasoseptal flap.

Minimally Invasive Lateral Paraorbital Approach for Repairing Lateral Recess of the Sphenoid Sinus Spinal Fluid Leak.

BACKGROUND: Cerebrospinal fluid (CSF) leaks in the lateral recess of the sphenoid sinus (LRSS) are typically spontaneous in nature and require surgical repair. Endoscopic endonasal approaches have become the mainstay of CSF leak repair in the LRSS, though they remain technically challenging and place the vidian nerve (VN) and sphenopalatine artery (SPA) at risk. Here we present a lateral paraorbital approach (LPOA) as a minimally invasive transcranial VN and SPA sparing alternative for LRSS CSF leak repairs. CASE DESCRIPTION: A 41-year-old African American woman presented with headaches and was found to have a spontaneous CSF leak in the LRSS. A LPOA was used to repair the CSF leak. An incision was made along the frontal process of zygoma (FPZ). Removal of the overhanging portion of the FPZ while sparing the lateral orbital rim and retraction of the temporalis muscle allowed for a tangential approach to the LRSS. A small encephalocele was seen and resected; the defect was identified and repaired with onlay DuraGen (Integra LifeSciences, Princeton, NJ) and Dura Repair (J&J Medical Devices, New Brunswick, NJ). There were no postoperative complications or recurrence of CSF leak. CONCLUSIONS: The LPOA can be a useful alternative approach to the LRSS for CSF leak repair. The lateral-to-medial approach to defects in this area provides a shorter working distance while avoiding critical neurovascular structures.

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.

Novel Use of Biodissolvable Stent in Treatment of Recurrent Rathke Cleft Cyst.

BACKGROUND: Rathke cleft cysts (RCCs) are benign cysts arising from the pars intermedia as a result of incomplete obliteration of the Rathke pouch during development of the pituitary gland. The most common presenting symptoms are headaches, visual disturbances, and endocrinopathies. Recurrence of RCCs after surgical treatment is a well-known phenomenon after surgery with reported recurrence rates as high as 30%. Various methods have been employed to reduce the rate of recurrence. Complete cyst wall resection has been associated with increased rates of perioperative cerebrospinal fluid leak, diabetes insipidus, and carotid injury, while inconsistently demonstrating reduced recurrence rates. Marsupialization, in which the cyst cavity is widely exposed and left open with or without a fat graft suspension, has similarly shown increased morbidity without clear improvement in outcomes. We report here the use of a steroid-eluting sinus stent to maintain patency of the cyst opening. CASE DESCRIPTION: A 39-year-old female presented with a symptomatic RCC. She underwent 4 different surgeries including cyst wall resection, marsupialization, and fat graft placement. She developed short-term symptomatic and radiographic recurrence within 3 months of each surgery. She then underwent placement of a steroid-eluting sinus stent. At 3 months, the patient remained symptom free, without radiographic recurrence and with patent cyst fenestration on nasal endoscopy. CONCLUSIONS: Recurrent RCCs are challenging to manage. Strategies to reduce recurrence are typically associated with higher risk and varying success. Stent placement represents a simple, low-risk method of potentially maintaining patency of cyst fenestration.

Endoscopic Endonasal Transrotundum Middle Fossa Exposure: Technique of Transpterygoid Maxillary Nerve Transposition.

OBJECTIVE: Middle fossa floor access can be challenging. Open skull base approaches have associated morbidity and yield suboptimal working angles around the temporal lobe. Endoscopic endonasal approaches to the middle fossa are poorly described, but provide an improved angle. I hypothesized that the length of the maxillary nerve can be transposed out of the foramen rotundum to provide a path to expose the full width of the middle fossa floor through the anterolateral and anteromedial triangle. METHODS: Endoscopic endonasal transpterygoid dissections to expose the middle fossa were performed bilaterally on 2 silicone-injected cadaveric heads (4 sides). Transposition of V2 was then performed on all sides, and additional middle fossa exposure was achieved. High-resolution computed tomography imaging was obtained to quantify the extent of exposure. A transzygomatic approach was also performed for comparison. RESULTS: The maxillary nerve was successfully transposed in each dissection. A periosteal fold was identified to assist in the mobilization of the infraorbital nerve. The average middle fossa exposure achieved without transposition was 50% (of the medial to lateral width). Transposition increased that to 95%. Comparison with the open transzygomatic approach demonstrated superior surgical trajectory (inferior to superior) with the endonasal route. CONCLUSIONS: Endoscopic endonasal transpterygoid approaches with or without transposition of the maxillary nerve provide a reasonable option for sequentially exposing the entire medial to lateral extent of the anterolateral triangle. It provides an advantageous inferior to superior surgical angle and can be considered for treatment of select middle fossa floor pathology.