Analysis of anterior and posterior maneuvers to enhance intraconal exposure.

BACKGROUND: The medial and inferior recti encompass the ideal surgical corridor to approach the intraconal space endonasally. Here, we describe 3 different maneuvers to achieve greater access to orbital contents through an expanded endonasal approach (EEA). METHODS: Four human cadaver heads were dissected bilaterally (n = 8). EEA to the medial intraconal orbit was executed. The following 3 maneuvers were performed: (1) anterior: extraocular muscles control (EOM); (2) posterior: annulus of Zinn (AZ) release; and (3) anterior/posterior combined. Measurements of the inferior and medial rectus corridor at the level of anterior ethmoidal artery (AEA) and posterior ethmoidal artery (PEA) and extent of optic nerve and medial rectus visualization was performed before and after each maneuver. RESULTS: Medial rectus length (MRL) and optic nerve length (ONL) achieved were 1.72 ± 0.28 cm and 0.85 ± 0.2 cm, respectively. Mean caudal-rostral distances between the rectus muscles at the level of the AEA and PEA were 3.45 ± 0.7 mm and 1.30 ± 0.3 mm, respectively. After EOM control, mean caudal-rostral distances at the same level were as follows: AEA 4.90 ± 1.15 mm (p = 0.009) and PEA 1.70 ± 0.20 mm (p = 0.016). With AZ release, MRL was 2.20 ± 0.7 cm (p = 0.002) and ONL was 1.30 ± 0.2 cm (p = 0.003), with mean rostral-caudal distance at the level of AEA at 4.03 ± 0.8 mm (p = 0.16) and PEA at 1.71 ± 0.36 mm (p = 0.039). Mean caudal-rostral distances achieved with AZ release and EOM control were as follows: AEA 5.6 ± 1.2 mm (p = 0.001) and PEA 2.15 ± 0.4 mm (p = 0.001). CONCLUSION: Progressive access to the orbital contents is afforded with the 3 delineated maneuvers. The magnitude of access is optimized with the combined maneuver. The actual anterior/posterior location of the target will determine which maneuvers are required.

The impact of total immunoglobulin E levels on outcomes of maximal medical therapy for chronic rhinosinusitis.

INTRODUCTION: The goal of this project was to evaluate the impact of immunoglobulin E (IgE) levels on outcomes in patients with chronic rhinosinusitis (CRS) who received maximal medical therapy (MMT). STUDY DESIGN: Prospective cohort study. METHODS: Thirty-eight patients who underwent MMT for CRS were assigned to three different cohorts based on their IgE levels: low IgE (<25 IU), moderate (>25 to <149 IU), and high (≥150 IU). The primary outcome evaluated was MMT failure with a surgical recommendation within each IgE cohort. Secondary outcomes included changes in pre- and post-MMT scores for the Rhinosinusitis Disability Index, Chronic Sinusitis Survey, and computed tomography-based Lund-Mackay evaluation. The cohorts were substratified based on the presence of nasal polyps and nasal allergies. RESULTS: No significant difference was found when MMT failure was compared between the cohorts in terms of quality of life. When substratified based on the presence of nasal polyps and nasal allergies, there was no significant difference between the cohorts. In the high-IgE cohort, all patients regardless of presence of nasal polyps and nasal allergic disease, frequently failed MMT and were recommended for surgery. CONCLUSIONS: Overall, IgE levels did not seem to have a significant effect on the quality of life or outcomes of MMT in the patients with CRS. However, the presence of nasal allergies regardless of IgE levels seemed to result in more frequent recommendations for surgery after MMT. In the patients with higher-IgE levels (≥150 IU), MMT seemed to fail at high rates with or without the presence of polyps or allergic disease.

Carotid artery and lower cranial nerve exposure with increasing surgical complexity to the parapharyngeal space.

OBJECTIVES/HYPOTHESIS: To investigate the extent of carotid artery exposure attained, including the identification of the external carotid branches and lower cranial nerves in five sequential external approaches to the parapharyngeal space, and to provide an anatomical algorithm. STUDY DESIGN: Anatomical study. METHODS: Six latex-injected adult cadaver heads were dissected in five consecutive approaches: transcervical approach with submandibular gland removal, posterior extension of the transcervical approach, transcervical approach with parotidectomy, parotidectomy with lateral mandibulotomy, and parotidectomy with mandibulectomy. The degree of carotid artery exposure attained, external carotid branches, and lower cranial nerves visualized was documented. RESULTS: The transcervical approach exposed 1.5 cm (Standard Deviation (SD) 0.5) of internal carotid artery (ICA) and 1.25 cm (SD 0.25) of external carotid artery (ECA). The superior thyroid and facial arteries and cranial nerve XII and XI were identified. The posterior extension exposed 2.9 cm (SD 0.7) of ICA and 2.7 cm (SD 1.0) of ECA. Occipital and ascending pharyngeal arteries were visualized. The transparotid approach exposed 4.0 cm (SD 1.1) of ICA and 3.98 cm (SD 1.8) of ECA. Lateral mandibulotomy exposed the internal maxillary artery, cranial nerve X, the sympathetic trunk, and 4.6 cm (SD 2.4) of ICA. Mandibulectomy allowed for complete ECA exposure, cranial nerve IX, lingual nerve, and 6.9 cm (SD 1.3) of ICA. CONCLUSION: Approaches for the parapharyngeal space must be based on anatomic and biological patient factors. This study provides a guide for the skull base surgeon for an extended approach based on the desired anatomic exposure. LEVEL OF EVIDENCE: N/A. Laryngoscope, 127:585-591, 2017.

A New Window for the Treatment of Posterior Cerebral Artery, Superior Cerebellar Artery, and Basilar Apex Aneurysm: The Expanded Endoscopic Endonasal Approach.

OBJECTIVE: To explore the feasibility of an endoscopic endonasal transclival approach to treat aneurysms arising in the basilar apex, posterior cerebral arteries, and superior cerebellar arteries. STUDY DESIGN: Cadaveric anatomical study. PARTICIPANTS: Fifteen cadaveric specimens. MAIN OUTCOME MEASURES: Degree of surgical exposure of each artery attained, distance from the nasal vestibule to these three arteries, and feasibility of clipping these vessels using standard vascular clip applicators. RESULTS: Both posterior cerebral arteries were exposed, 0.67 cm (standard deviation [SD]: 0.2) on the right side and 0.59 cm (SD: 0.2) on the left side. Both right and left superior cerebral arteries were exposed, 0.6 cm (SD: 0.2) and 0.7 cm (SD: 0.3), respectively. The length of the basilar artery exposed was 2.6 cm (SD: 0.3). The distance from the nasal vestibule to the posterior cerebral artery, superior cerebellar artery, and basilar apex was 10 cm with an SD of ± 0.7, 0.6, and 0.8 cm, respectively. We were able to apply clips on each of these three vessels with a minimal alteration of surrounding normal tissue. CONCLUSION: The endoscopic endonasal transclival approach represents a potentially feasible surgical corridor to treat aneurysms arising from these vessels.

Using the Endoscopic Endonasal Transclival Approach to Access Aneurysms Arising from AICA, PICA, and Vertebral Artery: An Anatomical Study.

Objective To explore the use of the endoscopic endonasal transclival approach (EEA) for clipping anterior inferior cerebellar artery (AICA), posterior inferior cerebellar artery (PICA), and vertebral artery (VA) aneurysms. Design Anatomical study. Participants Fifteen adult cadavers. Main Outcome Measures Length of artery exposed and distance from the nasal ala to the arteries. Results The length of the right and left VA exposed were 1.7 ± 0.6 cm and 1.6 ± 0.6 cm, respectively. The distance to the right VA was 11.1 ± 0.9 cm and to the left was 11.1 ± 0.8 cm. Right and left AICA were exposed for an average length of 1.1 ± 0.3 cm and 0.8 ± 0.3 cm, respectively. The distance to the right AICA was 10.3 ± 0.8 cm and to the left was 10.3 ± 0.8 cm. The right PICA was exposed for a length of 0.5 ± 0.2 cm at a distance of 10.9 ± 0.5 cm. The left PICA was exposed for a length of 0.5 ± 0.2 cm at a distance of 11.1 ± 0.9 cm. Conclusion The EEA can provide direct access to AICA, PICA, and VA, making it a potential alternative to the traditional approaches for the clipping of aneurysms arising from those arteries.

The Expanded Endoscopic Endonasal Approach to Anterior Communicating Artery Aneurysms: A Cadaveric Morphometric Study.

OBJECTIVE: The purpose of this study was to explore the endoscopic endonasal approach to the anterior communicating artery complex. DESIGN: Anatomic, morphometric analysis of human cadaver heads. SUBJECTS: Fifteen latex-injected adult cadaver heads. MAIN OUTCOME MEASURES: The anatomic boundaries of the operative field and the dimensions of exposure of the anterior communicating artery (ACoA) complex were measured and clip placement feasibility was assessed. RESULTS: Exposure of the ACoA and bilateral A1 and A2 segments was accomplished in all 15 cadaver heads. Average length of the exposed ACoA was 3 ± 1 mm, the left A1 was 5 ± 3 mm and right A1 was 5 ± 1 mm, while the A2 segment was 5 ± 2 mm bilaterally. The average distance from the alar floor to the ACoA was 95 mm, while proximal lateral limit measured between the alar floor margins was 36 mm. The distal lateral limit as defined by the distance between the lateral most exposed margins of the chiasm was 19 mm. Clip placement was accomplished for the ACoA and the A1 and A2 segments bilaterally in all specimens. CONCLUSION: The endoscopic, endonasal transtuberculum, transplanum approach is an anatomically feasible alternative to treating select aneurysms of the ACoA complex.

The Reverse-Flow Facial Artery Buccinator Flap for Skull Base Reconstruction: Key Anatomical and Technical Considerations.

Objective To highlight key anatomical and technical considerations for facial artery identification, and harvest and transposition of the facial artery buccinator (FAB) flap to facilitate its future use in anterior skull base reconstruction. Only a few studies have evaluated the reverse-flow FAB flap for skull base defects. Design Eight FAB flaps were raised in four cadaveric heads and divided into thirds; the facial artery's course at the superior and inferior borders of the flap was measured noting in which incisional third of the flap it laid. The flap's reach to the anterior cranial fossa, sella turcica, clival recess, and contralateral cribriform plate were studied. A clinical case and operative video are also presented. Results The facial artery had a near vertical course and stayed with the middle (⅝) or posterior third (⅜) of the flap in the inferior and superior incisions. Seven of eight flaps covered the sellar/planar regions. Only four of eight flaps covered the contralateral cribriform region. Lastly, none reached the middle third of the clivus. Conclusions The FAB flap requires an understanding of the facial artery's course, generally seen in the middle third of the flap, and is an appropriate alternative for sellar/planar and ipsilateral cribriform defects.