Surgical management of spontaneous middle cranial fossa defects: a systematic review and meta-analysis of available reconstructive techniques and materials.

Different materials and techniques have been proposed for surgical repair of spontaneous middle cranial fossa (MCF) defects. However, conclusive evidence supporting their selection and impact on clinical outcomes is lacking. The study aims to conduct a systematic review and meta-analysis on materials and techniques employed to repair MCF defects and evaluate complications and rates of recurrent cerebrospinal fluid (CSF) leaks. A PRISMA-guided systematic review and meta-analysis were performed using MESH terms and specific keywords including studies published before May 2022. Primary outcomes included recurrence of CSF leak and complication rates by type of reconstructive material and technique utilized. Meta-analyses of proportions were performed using random effects and confidence intervals for individual proportions were calculated using the Clopper-Pearson method. Twenty-nine studies were included (n = 471 cases). Materials employed for repair were categorized according to defect size: 65% of defects were of unknown size, 24% were small (< 1 cm), and 11% were large (≥ 1 cm). Rigid reconstruction (RR) was significantly favored over soft reconstruction (SR) for larger defects (94% of cases, p < 0.05). Complications and recurrent CSF leak rates of SR and RR techniques were comparable for defects of all sizes (p > 0.05). Complication rates reported for these procedures are low regardless of technique and material. RR was universally preferred for larger defects and analysis of complication and recurrence rates did not reveal differences regardless of defect size. While RR was more frequently reported in smaller defects, SR was used by several centers, particularly for smaller MCF floor defects.

Purely nasal floor mucosa-free graft for reconstruction after endoscopic endonasal transellar approach: an anatomical and clinical analysis.

BACKGROUND/OBJECTIVE: In this radioanatomical study with clinical correlate, we study a variation of the 'extended nasal floor mucosa' (ENFM) free-graft, the purely nasal floor mucosa (PuNFM) free-graft. The objectives of this study are to evaluate the coverage surface area provided by the PuNFM, study the adequacy of the PuNFM in the reconstruction of endoscopic endonasal approach (EEA) transsellar postoperative defects and compare and evaluate this reconstructive technique with current sellar region reconstruction practices. METHODS: Dissections were performed on five cadaveric specimens. PuNFM were harvested bilaterally and the area provided for reconstruction was calculated. Twenty-five consecutive cases of pituitary adenomas resected through an EEA were analyzed to estimate the sellar defect surface area (SDSA) after a transsellar EEA and calculate the area of PuNFM bilaterally. RESULTS: The median cadaveric SDSA was 4.77 cm2, with a median left and right side PuNFM area of 5.09 and 5.19 cm2, respectively. Clinically, the median SDSA was 5.36 cm2, and the total radiological PuNFM surface area was 5.46 cm2, with modified Knosp grade >2 tumors having larger SDSA than that of Knosp grade <2 tumors. The PuNFM graft proved to be most effective for covering modified Knosp <2 tumor defects. CONCLUSIONS: The PuNFM represents a variation of the ENFM free-graft sellar defect reconstruction technique that provides sufficient surface area to reconstruct the majority of the sellar defects related to transsellar EAA for pituitary adenomas. This technique may positively impact sinonasal function and quality of life. Future prospective clinical studies are needed to verify these findings.

Pedicled lateral nasal wall flap for the reconstruction of the nasal septum perforation. A radio-anatomical study.

INTRODUCTION: The aim of this radio-anatomical study is to ensure that the potential donor area of the pedicled lateral nasal wall flap (PLNW) is adequate to reconstruct nasal perforation. MATERIAL AND METHODS: Analysis was conducted on 40 de-identified CT angiographies. The area and length of the PLNW, the septum, and the nasal floor were measured. In a cadaver study, 20 hemi-cranial sagittal sections were also analyzed. The anterior-posterior length of the PLNW flap and the distance between the sphenopalatine foramen and piriform aperture were measured. A clinical study with endoscopic closure of a large perforation was conducted in three patients. RESULTS: The CT angiographies demonstrated an average PLNW area of 10.80±1.13 cm2 and a nasal floor area of 3.78±0.58 cm2. The septal area (22.54±21.32 cm2) was significantly larger than the total PLNW flap area (14.59±1.21 cm2). The average length of the flap was 5.58±0.39 cm, while the septum was 6.66±0.42 cm; therefore the PLNW flap is insufficient to reconstruct the entire septum. The cadaver study showed that the length of the PLNW flap was 5.28±0.40 cm. These results demonstrate that measurements obtained from CT scans are reliable data and similar to those found in the radiological study. Complete closure was achieved in all three patients. CONCLUSION: The PLNW flap does not render enough tissue to reconstruct a total septal perforation; however, up to 84% of the septum could be repaired with a PLNW. The potential donor area obtained by CT scan and clinical practice support the approachability of PLNW to repair large septal perforation.

Meckel's cave access: anatomic study comparing the endoscopic transantral and endonasal approaches.

Recent advances in endonasal endoscopy have facilitated the surgical access to the lateral skull base including areas such as Meckel's cave. This approach has been well documented, however, few studies have outlined transantral specific access to Meckel's. A transantral approach provides a direct pathway to this region obviating the need for extensive endonasal and transsphenoidal resection. Our aim in this study is to compare the anatomical perspectives obtained in endonasal and transantral approaches. We prepared 14 cadaveric specimens with intravascular injections of colored latex. Eight cadavers underwent endoscopic endonasal transpterygoid approaches to Meckel's cave. Six additional specimens underwent an endoscopic transantral approach to the same region. Photographic evidence was obtained for review. 30 CT scans were analyzed to measure comparative distances to Meckel's cave for both approaches. The endoscopic approaches provided a direct access to the anterior and inferior portions of Meckel's cave. However, the transantral approach required shorter instrumentation, and did not require clearing of the endonasal corridor. This approach gave an anterior view of Meckel's cave making posterior dissection more difficult. A transantral approach to Meckel's cave provides access similar to the endonasal approach with minimal invasiveness. Some of the morbidity associated with extensive endonasal resection could possibly be avoided. Better understanding of the complex skull base anatomy, from different perspectives, helps to improve current endoscopic skull base surgery and to develop new alternatives, consequently, leading to improvements in safety and efficacy.

Anatomic analysis specific for the endoscopic approach to the inferior, medial and lateral orbit.

INTRODUCTION: The endoscopic approaches to the medial and inferior orbital walls have continued to grow in popularity. The ability to provide a safe approach to the orbit through this technique has been described in a handful of studies. Even though metric analyses have been conducted on orbital anatomy, few have outlined the anatomical relations pertinent to endoscopic surgery. The goal is to provide improved understanding of the complex anatomy encountered through anatomical dissections and metric analysis of the orbit. This information could assist in approach selection during preoperative planning. METHODS: Anatomical dissections via transantral and endonasal approaches were used to define the limits with current endoscopic sinus surgery instrumentation. The surface area was then calculated of the floor and medial wall to assess access created by the approaches. The path of the infraorbital canal was conducted to assess its placement within the orbital floor. RESULTS: The transantral and endonasal approaches to the orbit provided an adequate surgical window inferiorly and medially. This was confirmed by the surface area calculations. Access laterally was also possible, however, it became limited as dissection advanced superior to the lateral rectus muscle. The infraorbital canal was located consistently at midline on the orbital floor. CONCLUSION: Endoscopic access to the medial and inferior parts of the orbit is feasible and creates adequate access with current instrumentation. Knowing the surgical boundaries and the amount of exposure created can assist the surgeon in deciding a minimally invasive approach.

Exoscope-assisted temporal bone resection: operative videos of the lateral and total techniques.

Skull base malignancies arising from the parotid gland, skin, or external auditory canal (EAC) can potentially involve the temporal bone. Management of these invasive tumors represents a true challenge considering the critical neurovascular relationships. Exoscope-assisted temporal bone resection (TBR) plays a crucial role in addressing such malignancies. The extent of disease is evaluated using the Pittsburgh staging system, which then guides the boundaries of resection. Lateral TBR (LTBR) relies on removal of the EAC and lateral ossicles and is generally appropriate for stage T1 and T2 tumors. Total TBR (TTBR) is reserved for high-grade tumors involving the petrous apex. The video can be found here: https://stream.cadmore.media/r10.3171/2023.10.FOCVID23135.

The vectorial technique: a novel neuronavigation-based tool to measure angles of exposure during skull base dissections.

The angle of exposure (AnE) represents a metric that is particularly useful for analyzing circular bony structures during skull base dissections. The authors aimed to develop and validate a neuronavigation-based method to measure the AnE. A formula based on vectorial geometry and the coordinates of three points collected with a neuronavigation system was developed to measure the AnE. The method was validated using a plexiglass phantom head. To demonstrate its applicability, the authors measured the AnE in 6 cadaveric specimens after exposure of the hypoglossal canal using a far-medial approach (FMA) and a far-lateral transtubercular approach (FLTA) and in 6 different specimens after exposure of the jugular foramen using an FLTA and a retrosigmoid approach (RSA). The mean angles measured at 45°, 90°, and 180° using a goniometer during the validation test were 44.8° ± 1.1°, 90.8° ± 1.2°, and 179.7° ± 0.8° using the novel formula (p > 0.05). In the first illustrative application, the mean AnEs for the FMA and FLTA were 129° ± 0.9° and 243° ± 1.9°, respectively. In the second scenario, the mean AnEs were 192° ± 1.3° for the FTLA and 143° ± 2.1° for the RSA. The neuronavigation-based technique described is a highly accurate method to measure the AnE.

Biportal Endoscopic TransOrbital and transMaxillary Approach to the Cranio-Orbital Region and Middle Cranial Fossa: A Preliminary Analysis of Maneuverability.

BACKGROUND AND OBJECTIVES: Traditional and well-established transcranial approaches to the spheno-orbital region and middle cranial fossa guarantee optimal intracranial exposure, and additional orbital and zygomatic osteotomies provide further control over extracranial components to be resected; however, these techniques come at the cost of additional morbidity. The introduction of minimally invasive endoscopic approaches and the conceptualization of the so-called "multiportal" paradigm might provide an alternative route. This preliminary study investigates the feasibility of the combined Biportal Endoscopic TransOrbital and transMaxillary Approach (bETOMA) approach to the spheno-orbital and middle cranial fossa regions. METHODS: Using 4 silicon-injected adult cadaver heads (8 sides; 16 approaches), we systematically dissected through superior eyelid ETOA and endoscopic TMA approaches. The analysis focused on pterygopalatine, infratemporal, anterior and middle cranial fossae, Meckel cave, and cavernous sinus access. We evaluated the feasibility of bETOMA using linear distances, angles of attack, and exposure areas. We also introduced volume of operative maneuverability, its standardized derivative (sVOM), target distance, visuo-operative angle, and working zone volume as novel metrics. RESULTS: The analysis revealed comparable angles of attack between approaches. ETOA and TMA exposure areas were 918.38 ± 223.93 mm2 and 257.07 ± 86.07 mm2, respectively. TMA showed a larger VOM in the greater sphenoid wing, but ETOA offered superior distal maneuverability (sVOM: 5.39 ± 1.94 vs 2.54 ± 0.79 cm3) and closer intracranial space access (27.45 vs 50.83 mm). The combined approaches yielded a mean working zone volume of 13.75 ± 3.73 cm3 in the spheno-orbital interface. CONCLUSION: The bETOMA approach provides adequate neurovascular exposure and maneuverability to the spheno-orbital region, infratemporal, and anterior and middle cranial fossae, addressing significant limitations of previously investigated monoportal techniques (ie, optic nerve decompression, hyperostotic bone resection, and infratemporal exposure). This combined minimally invasive approach might help manage lesions harbored within the cranio-orbital interface region invading the extracranial space.

Contralateral Transmaxillary Approach to Petrous Apex Granuloma with Lateral Maxillotomy: 2-Dimensional Operative Video.

The endoscopic endonasal approach (EEA) has proven to be a valuable tool to access the petrous apex (PA).1 Although lesions located medial to the PA can be easily accessed through an EEA with minimal risk to the internal carotid artery (ICA), more laterally seated lesions represent a surgical challenge. The contralateral transmaxillary approach is an effective extension of the normal EEA to the PA, allowing a more lateral trajectory and thereby reducing the risks connected to paraclival ICA manipulation.2-4 This is a 47-year-old female presenting with tinnitus, hearing loss, and right facial twitching. The preoperative audiogram showed a 60 dB sensorineural hearing loss, and magnetic resonance imaging demonstrated an expansive lesion of the PA with high signal intensity in T1- and T2-weighted sequences. A high-riding jugular bulb ruled out the use of an infracochlear infralabyrinthine approach, and a middle cranial fossa approach was felt to render a high risk of recurrence due to the potential for incomplete resection. Ultimately, a contralateral transmaxillary approach was selected. Due to the extreme lateral position of the lesion, the maxillotomy was created in the lateral wall of the maxillary sinus to allow a coaxial approach to the PA. Postoperatively, the patient did not report new neurologic deficits. Anatomic pathology was consistent with cholesterol granuloma (Video 1). In the surgical management of PA granulomas, recognizing relevant anatomic structures such as the paraclival ICA, cochlea, jugular bulb, and vestibule preoperatively is of paramount importance to tailor the surgical approach and reduce its risks.

Radial Forearm Free Flap with Parapharyngeal Pedicle Corridor for Reconstruction of Anterior Skull Base Defects.

BACKGROUND: The radial forearm free flap (RFFF) is an indispensable tool for the reconstruction of a range of defects, including those of the skull base. Several options for routing of the RFFF pedicle have been described, and the parapharyngeal corridor (PC) has been proposed as an option and employed for a nasopharyngeal defect. However, there are no reports of its use for the reconstruction of anterior skull base defects. The objective of this study is to describe the technique for free tissue reconstruction of anterior skull base defects using the RFFF and routing of the pedicle via the PC. METHODS: Relevant neurovascular landmarks and critical surgical steps for reconstruction of anterior skull base defects with an RFFF and routing of the pedicle via the PC are reported using an illustrative clinical case and cadaveric dissections. RESULTS: We present a case of a 70-year-old man who underwent endoscopic transcribriform resection of cT4N0 sinonasal squamous cell carcinoma and was left with a large anterior skull base defect that persisted despite several repair attempts. An RFFF was utilized to repair the defect. This report is the first description of the clinical use of the PC for free tissue repair of an anterior skull base defect. CONCLUSIONS: The PC is an option for routing the pedicle during the reconstruction of anterior skull base defects. When the corridor is prepared as described in this case, a direct route exists from the anterior skull base to cervical vessels, simultaneously maximizing the reach of the pedicle and minimizing the risk of kinking.

A Cost-Effective and Reproducible Cadaveric Training Model for Internal Carotid Artery Injury Management During Endoscopic Endonasal Surgery: The Submersible Peristaltic Pump.

BACKGROUND: Internal carotid artery injury (ICAI) represents one of the most challenging complications in endoscopic endonasal neurosurgery and its rarity results in limited opportunities for trainees and surgeons to achieve proficiency in its management. Currently, available models for ICAI have employed costly systems that prevent their widespread use. The objective of this study is to validate an affordable submersible peristaltic pump (SPP)-based model as a reproducible and realistic paradigm for ICAI management training. METHODS: A laceration of the left parasellar internal carotid artery was purposely carried out in 2 human cadaveric heads. A blood substitute was perfused to ensure a perfusion flow of 1 L/min using an affordable SPP. A cohort of 20 neurosurgery and otolaryngology residents, fellows, and attendings were enrolled to evaluate the realism and content validity of the model using a validated 5-grade questionnaire. RESULTS: The model proved to mimic a real intraoperative scenario of ICAI with an expected output flow of 1 L/min. Questionnaire responses reported a realistic experience and the impact of this model on improving trainee surgical coordination and capability to rehearse the most accepted repair technique. The use of a fixed noninjected head allowed the reproducibility of the training session without the additional cost of new fresh-frozen heads. The affordable SPP allowed an impactful reduction of ICAI model training expenses maintaining high realism. CONCLUSIONS: The SPP-based ICAI model with noninjected cadaveric specimens is an affordable and cost-effective system that allows reproducibility and realism. These qualities favor greater adoption in neurosurgery and otolaryngology training curricula.

Thermal Analysis of an Ultrasonic Aspirator Micro Claw Tool Compared With Standard High-Speed Drilling During Internal Auditory Canal Opening in a Cadaveric Model.

BACKGROUND: The ultrasonic aspirator micro claw tool (UAmCT) can be used to remove the bone of the internal auditory canal (IAC) during vestibular schwannoma resection via the retrosigmoid approach (RSA) without the risk of a spinning drill shaft. However, the thermal profile of the UAmCT during IAC removal has not been reported. OBJECTIVE: To compare the thermal profile of the UAmCT during access of the IAC to that of a conventional high-speed drill (HSD) and to present an illustrative case of this application. METHODS: IAC opening via RSA was performed in 5 embalmed cadaveric specimens using the UAmCT with 3, 8, and 15 mL/min irrigation on the left and the HSD at 75 000 revolutions per minute and 0%, 14%, and 22% irrigation on the right. Peak bone surface temperatures were measured 4 times in 20-second intervals, and statistical analyses were performed using SPSS software. An illustrative case of a vestibular schwannoma resected via an RSA using the UAmCT to access the IAC is presented. RESULTS: The IAC was opened in all 5 specimens using both the UAmCT and HSD without complication. The mean peak bone surface temperatures were significantly lower with the UAmCT compared with the HSD ( P < .001). The UAmCT did not meaningfully prolong the operating time in the illustrative case, and the IAC was accessed without complication. CONCLUSION: The UAmCT may be a safe and effective alternative to HSD for IAC opening during vestibular schwannoma resection via the RSA. Larger studies under clinical conditions are required to further validate these findings.

Three-Dimensional Exoscopic Temporal Bone Resections for Advanced Head and Neck Cancer.

Objectives The three-dimensional (3D) exoscope has several advantages over the operative microscope (OM) but has not been extensively reported for its use in malignant temporal bone resections (TBR). We sought to demonstrate the feasibility of performing TBR, both lateral (LTBR) and subtotal (STBR), using the 3D exoscope for head and neck cancers. Design present study is a retrospective chart review from August 2016 until August 2019. Setting The study was conducted at a tertiary care center. Participants Patients were undergoing TBR with the Karl Storz VITOM 3D exoscope. Main Outcome Measures Demographics, tumor and surgical characteristics, patient outcomes were the primary measurements of this study. Results Fifty-five patients underwent 3D exoscopic TBR from 2016 through 2019 of which 18% ( n = 10) underwent STBR. The 3D exoscope was used uninterruptedly in all procedures with no intraoperative complications. Most tumors were primarily T3 (42%, n = 23) or T4 (55%, n = 30) and of cutaneous (62%, n = 34) and parotid (27%, n = 15) origin. These TBR were often accompanied by infratemporal fossa resections (87%, n = 48), auriculectomies (47%, n = 26), mandibulectomies (53%, n = 29), and parotidectomies (96%, n = 53). On final pathology, 24% ( n = 13) had microscopically positive margins. Over the study period, 20% ( n = 11) of patients had recurrences with a median recurrence time of 5 months (range: 2-30 months). Conclusion In the largest case series of LTBR and STBR under exclusive 3D exoscopic visualization to date, we demonstrate the 3D exoscope is a feasible alternative to the operative microscope for LTBR and STBR. While oncologic outcomes remain to be clarified, it carries significant potential for use in complex oncologic procedures.

Retrosigmoid Vestibular Neurectomy for Meniere Disease: A Technical Note.

BACKGROUND: Meniere disease (MD) is an idiopathic peripheral pathology involving the acoustic apparatus. One of the most critical challenges in managing MD is intractable vertigo. In this context, retrosigmoid vestibular neurectomy has been described as a safe and effective technique to manage this symptom when it is resistant to first- and second-line treatments. This article analyzed the alternative treatment options, specific surgical anatomy, and relevant details of vestibular neurectomies performed for intractable MD. METHODS: Relevant neurovascular landmarks, critical surgical steps, adequate indications, and potential pitfalls of retrosigmoid vestibular neurectomy were analyzed based on an illustrative clinical case of intractable MD. RESULTS: The illustrative case demonstrated how early recognition of the facial nerve and the vestibulocochlear plane is fundamental to performing retrosigmoid vestibular neurectomy. This procedure is indicated in cases of resistant MD with preoperative hearing integrity. Potential pitfalls of this technique are incomplete neurotomy, nerve regeneration, comorbidities in the contralateral ear, adverse anatomy, the possibility of nonotologic vertigo, and incomplete vestibular compensation. CONCLUSIONS: Vestibular neurectomy represents a safe and effective technique to manage MD that is resistant to medical treatment, allowing symptom control and hearing preservation. Nevertheless, detailed knowledge of surgical anatomy and possible pitfalls is of paramount importance to achieve a good outcome.

Keyhole supraorbital eyebrow approach for the resection of a tuberculum sellae meningioma with intraoperative endoscopic assistance.

Background: Tuberculum sellae meningiomas represent approximately 5-10% of intracranial meningiomas.[2] Although benign, they are associated with substantial morbidity, especially visual disturbance. At present, there are three main treatment options for patients with tuberculum sellae meningiomas: observational, with serial imaging follow; microsurgical resection; and stereotactic radiosurgery. The advantages of the supraorbital eyebrow craniotomy are the direct visualization of the anterior cranial fossa, anterior circulation, and the optical apparatus, reducing the extent of brain retraction, and the absence of risks of temporalis muscle hypotrophy and posterior chewing discomfort. Conversely, minor drawbacks are a steeper learning curve related to a narrower surgical corridor than a standard frontotemporal approach and the minimal risk of supraorbital nerve injury.[1,3]. Case Description: The authors report the case of a 42-year-old female who presented with acute-onset vision loss and only finger counting in her left eye associated with headache. Magnetic resonance imaging (MRI) showed a suprasellar extra-axial T1 enhancing mass with encasement of the left optic nerve and paraclinoid internal carotid artery and mass effect on the optic chiasm. A keyhole supraorbital eyebrow approach assisted with a microinspection tool was performed for tumor resection and optic nerve decompression. A Simpson Grade 2 tumor resection was achieved, and histopathology revealed a WHO Grade-I tuberculum sellae meningioma. The patient's presentation, rationale, key surgical steps, and outcome are discussed, and informed consent for surgery and video recording was obtained. Conclusion: This surgical video illustrates the use of a keyhole supraorbital eyebrow approach assisted with a microinspection endoscopic tool for the resection of a tuberculum sellae meningioma. The tumor size, extension, and preoperative clinical status determine the optimal surgical corridor in tuberculum sellae meningioma. The keyhole supraorbital eyebrow approach allows safe and direct access to anterior cranial fossa lesions.

Microsurgical Gross Total Resection of an Intracanalicular-Cisternal (Koos-4) Vestibular Schwannoma via a Retrosigmoid Approach with Intraoperative Endoscopic Assistance.

We present the case of a 23-year-old female with a history of progressive hearing loss in the left ear, dizziness, and vertigo. Magnetic resonance imaging demonstrated a left mass extending from the internal auditory canal into the cerebellopontine angle (Koos-4).1 A retrosigmoid approach assisted with a microinspection tool was chosen.2-5 Microsurgical near total resection was achieved. The patient presented a postoperative facial deficit (House-Brackman grade 2 postoperative), with complete resolution after 2 months. Video 1 highlights the critical steps of the retrosigmoid approach and the benefit of using the microinspection tool for vestibular schwannoma resection.

Exoscopic En Bloc Carotid-Sparing Total Temporal Bone Resection: Feasibility Study and Operative Technique.

OBJECTIVE: To delineate the steps of exoscopic en bloc carotid artery-sparing total temporal bone resection for malignancies involving the temporal bone in a cadaveric model. METHODS: Dissections were performed on 3 right-sided (3 sides) formalin-fixed, latex-injected cadaveric specimens. An exoscopic en bloc carotid artery-sparing total temporal bone resection was performed on each cadaver. In the past 4 years, 8 patients have undergone exoscope-assisted internal carotid artery-sparing total temporal bone resection with the technique described in this report. As an example, we present a representative case of a patient in whom this technique was used. RESULTS: Exoscope-assisted en bloc total temporal bone resections were performed on 3 right-sided cadaveric specimens. The following steps were described to circumferentially expose the petrous temporal bone: infratemporal fossa exposure, temporal craniotomy for subtemporal middle fossa approach to the petrous bone, retrosigmoid craniotomy, and transjugular approach. Finally, 3 skull base osteotomies were performed to liberate anterior, medial, posterior attachments of the petrous bone for en bloc removal. Possible extensions of these dissections as indicated by tumor pathology were described. A case illustration and operative video utilizing these techniques is presented. CONCLUSIONS: Exoscope-assisted en bloc carotid artery-sparing total temporal bone resection is a feasible technique for management of malignancies with temporal bone invasion.

Exoscope-Assisted Middle Cranial Fossa Approach for Repair of Tegmental Defects: A Cadaveric and Clinical Study.

BACKGROUND: Recent studies highlighted how exoscopes may be employed to approach the lateral skull base. The use of exoscope-assisted procedures to repair middle cranial fossa (MCF) defects has not been fully explored. The surgical microscope in the same circumstances has been associated with relevant limitations, such as its physical obstruction, among others. The aim of this study was to present a proof of concept of exoscope-assisted surgery for MCF defects. METHODS: A detailed step-by-step MCF approach was performed on 2 alcohol-preserved, latex-injected cadaveric specimens under exoscopic magnification. An illustrative clinical case of encephalocele secondary to a spontaneous tegmen tympani defect repaired via an exoscope-assisted MCF approach was presented. RESULTS: The most common sites of MCF defects, the tegmen tympani and the arcuate eminence, were successfully exposed under exoscopic magnification. Dissection was easily performed; no damage to the dura mater or to vascular or neural structures occurred. In the clinical case, the exoscope-assisted technique demonstrated adequate maneuverability and magnification quality. After localization, the encephalocele was resected, and the MCF defect was repaired. The surgeon's position was comfortable, and operative time was not prolonged. CONCLUSIONS: The exoscope allows adequate exposure of the MCF floor with identification and preservation of key anatomical structures. The exoscope represents a valuable alternative to the microscope in reconstruction of MCF defects, offering high-quality magnification and proven maneuverability.

Endoscopic Transnasal Odontoidectomy.

Objectives The video demonstrates the steps for an endoscopic transnasal approach for resection of the odontoid causing platybasia with basilar invasion. Design The video reviews the clinical presentation, preoperative workup and imaging, patient positioning, technical nuances of the procedure, reconstruction, and clinical outcomes including postoperative imaging. Setting The surgery was performed by a skull base team including otolaryngologists and neurological surgeons at a large regional tertiary care facility. Participants A 59-year-old female with the Chiari I malformation with history of multiple revision cervical spinal surgeries presents with neck pain. Preoperative imaging showed a hypoplastic clivus and platybasia with basilar invasion. Main Outcome Measures The main outcome measures consist of safely removing the odontoid with appropriate closure, reversal of the patient symptoms, and prevention of both operative complications and ventral compression of the brainstem. Results The patient's neck pain improved. There were no intraoperative or postoperative complications besides anterior rightward nasal septal deviation causing unilateral nasal obstruction. A septoplasty was performed to correct the septal deviation 6 months after the initial procedure. Conclusions The endoscopic transnasal approach to the resection of odontoid is a safe and effective treatment to address basilar invasion and ventral compression of the brainstem. The link to the video can be found at: https://youtu.be/m_c3-Vn-l80 .

Rare Case of a Disappearing Pituitary Adenoma During the Coronavirus Disease 2019 (COVID-19) Pandemic.

We present a case of a 28-year-old woman with a history of severe headaches and pituitary insufficiency. She was found to have a large, enhancing, sellar mass consistent with a pituitary adenoma. The patient's surgical care was delayed due to the coronavirus disease 2019 (COVID-19) pandemic, and follow-up imaging revealed spontaneous involution of the sellar mass. Spontaneous involution of pituitary masses has been described but not often encountered in clinical practice. This case highlights that follow-up imaging is necessary when scheduling elective surgeries during the COVID-19 pandemic.