Middle Fossa Research Articles

Topographic Anatomy and Pneumatization of the Posterior Clinoid Process in Chiari Type I Malformation

ObjectiveThis study aimed to examine pneumatization and topographic location of the posterior clinoid process (PCP) in Chiari type I malformation (CIM) for skull base approaches. MethodsComputed tomography images of 52 (23 males / 29 females) CIM subjects aged 23.87±16.09 years, and 71 (26 males / 45 females) healthy subjects aged 42.48±21.48 years constituted the study universe. ResultsThe distances of PCP to the foramen magnum (p=0.037), superior orbital fissure (p<0.001), foramen rotundum (p<0.001), and foramen ovale (p<0.001) were smaller, but the distance of PCP to the crista galli (p=0.038) was greater in CIM patients, compared to normal subjects. In CIM, the fusion between PCP and the anterior clinoid process was observed in nine sides (8.70%), while in controls, in 12 sides (8.50%). PCP pneumatization was observed in 40 sides (38.50%) in CIM patients, while in 28 sides (19.70%) in normal subjects. This data displayed that PCP pneumatization was affected by CIM (p<0.001). ConclusionThe distances of PCP to the crista galli and foramen magnum indicate the anterior fossa length and the posterior fossa depth, respectively; thus, CIM patients have longer anterior fossa and shallow posterior fossa. In addition, the distances of PCP to superior orbital fissure, foramen rotundum and foramen ovale indicate the middle fossa width; thence, CIM patients have less middle fossa width than normal individuals. CIM patients have approximately 50% higher PCP pneumatization rate, and this may increase the risk of complications such as cerebrospinal fluid fistula during the application of posterior clinoidectomy.

Opioid Prescribing Patterns Following Lateral Skull Base Spontaneous Cerebrospinal Fluid Leak Repair.

To characterize the opioid prescribing patterns for and requirements of patients undergoing repair of spontaneous cerebrospinal fluid (sCSF) leaks of the lateral skull base. Retrospective chart review. Tertiary referral center. Adults with lateral skull base sCSF leaks who underwent repairs between September 1, 2014, and December 31, 2020. Mean morphine milligram equivalents (MMEs) of opioids dispensed to inpatients and prescribed at discharge, additional pain control medications dispensed, and outpatient additional opioid requests were compared between groups. Of 78 patients included, 46 (59%) underwent repair via a transmastoid (TM), 6 (7.7%) via a middle cranial fossa (MCF), and 26 (33.3%) via a combined TM-MCF approach. Inpatients received a mean of 21.3, 31.4, and 37.6 MMEs per day during admission for the TM, MCF, and combined TM-MCF approaches, respectively ( p = 0.019, ηp 2 = 0.101). Upon discharge, nearly all patients (n = 74, 94.9%) received opioids; 27.3, 32.5, and 37.6 MMEs per day were prescribed after the TM, MCF, and TM-MCF approaches, respectively ( p = 0.015, ηp 2 = 0.093). Five (6.4%) patients requested additional outpatient pain medication, after which three were prescribed 36.7 MMEs per day. Patients with idiopathic intracranial hypertension required significantly more inpatient MMEs than those without (41.5 versus 25.2, p = 0.02, d = 0.689), as did patients with a history of headaches (39.6 versus 23.6, p = 0.042, d = 0.684). Patients undergoing sCSF leak repair via the MCF or TM-MCF approaches are prescribed more opioids postoperatively than patients undergoing the TM approach. Patients with a history of headaches or idiopathic intracranial hypertension might require more opioids postoperatively.

Infantile Acute Subdural Hematohygroma: A Clinical and Neuroimaging Analysis of 18 Cases

&amp;lt;i&amp;gt;Objective&amp;lt;/i&amp;gt;: Even after the advent of magnetic resonance imaging (MRI), few studies have focused on the clinical profiles and neuroimaging characteristics of acute subdural hematohygroma (ASDHy) in infants. The present study attempted to elucidate the pathogenesis of ASDHy by analyzing the clinical and neuroimaging findings of ASDHy. &amp;lt;i&amp;gt;Materials &amp; Methods&amp;lt;/i&amp;gt;: The subjects were 18 patients (eight males and ten females) younger than 2 years with ASDHy. Their median age at diagnosis was 3.8 months (range: 2-10 months), and 15 (83%) were younger than 4 months. Imaging studies found no evidence of any primary brain injury. &amp;lt;i&amp;gt;Results&amp;lt;/i&amp;gt;: Five patients experienced a fall, and 13 (72%) had no history of head trauma. The presenting symptoms and signs were the acute onset of generalized convulsive seizures and or repeated vomiting. Retinal hemorrhage occurred in 14 patients (78%). The imaging studies revealed a large amount of bilateral, subdural fluid collection with an intensity higher than that of cerebrospinal fluid on MRI. Benign enlargement of the subarachnoid space (BESS) was found in 14 patients (78%), an enlarged sylvian fissure (LSF) was found in all the patients (100%), and greater, left-sided enlargement was evident in 16 patients (89%). Two patients underwent subdural drainage, and 16 patients (89%) were conservatively managed. All the patients had a favorable outcome. &amp;lt;i&amp;gt;Conclusions&amp;lt;/i&amp;gt;: ASDHy is a self-limiting disorder associated with retinal hemorrhage and a benign clinical course. Most cases develop in early infancy. LSF presumably loosens the tight fixation of the temporal lobes at the middle cranial fossa, thereby increasing the rotational force of the brain even during mild or unnoticeable impacts. Increased cranio-cerebral disproportion, including BESS and LSF, is a structural vulnerability which can lead to ASDHy in early infancy.

Pin penetration depths in the neurocranium using a three-pin head fixation device

In estimated 10–15% of neurosurgical interventions employing a conventional three-pin head fixation device (HFD) the patient’s head loses position due to slippage. At present no scientifically based stability criterion exists to potentially prevent the intraoperative loss of head position or skull fractures. Here, data on the skull penetration depth both on the single and two-pin side of a three-pin HFD are presented, providing scientific evidence for a stability criterion for the invasive three-pin head fixation. Eight fresh, chemically untreated human cadaveric heads were sequentially pinned 90 times in total in a noncommercially calibrated clamp screw applying a predefined force of 270 N (approximately 60 lbf) throughout. Three head positions were pinned each in standardized manner for the following approaches: prone, middle fossa, pterional. Titanium-aluminum alloy pins were used, varying the pin-cone angle on the single-pin side from 36° to 55° and on the two-pin side from 25° to 36°. The bone-penetration depths were directly measured by a dial gauge on neurocranium. The penetration depths on the single-pin side ranged from 0.00 mm (i.e., no penetration) to 6.17 mm. The penetration depths on the two-pin side ranged from 0.00 mm (no penetration) to 4.48 mm. We measured a significantly higher penetration depth for the anterior pin in comparison to the posterior pin on the two-pin side in prone position. One pin configuration (50°/25°) resulted in a quasi-homogenous pin depth distribution between the single- and the two-pin side. Emanating from the physical principle that pin depths behave proportionate to pin pressure distribution, a quasi-homogenous pin penetration depth may result in higher resilience against external shear forces or torque, thus reducing potential complications such as slippage and depressed skull fractures. The authors propose that the pin configuration of 50°/25° may be superior to the currently used uniform pin-cone angle distribution in common clinical practice (36°/36°). However, future research may identify additional influencing factors to improve head fixation stability.

Patient Sex Mediates the Influence of Patient Age on Superior Canal Dehiscence Repair Outcome.

To investigate the independent and interactive effects of patient age and sex on superior canal dehiscence (SCD) repair outcomes. This was a cohort study of consecutive SCD repairs via the middle fossa approach at an institution between 2011 and 2022. We constructed multivariable regression models assessing surgical outcomes with age and sex as the primary predictors. Models controlled for surgery duration, follow-up duration, and relevant surgical and medical history. Subsequently, we repeated each model with the incorporation of an interaction term between patient age and sex. Among 402 repairs, average age was 50 years, and 63% of cases were females. There was a significant interaction between patient age and sex with respect to symptom resolution score (SRS) (adj. β 0.80, 95% C.I. 0.04-1.56). Older age was associated with lower SRS among females (-0.84, -1.29 to -0.39 point per year) but not significantly associated with SRS among males (0.04, -0.65 to 0.56 point per year). Furthermore, older age independently predicted a greater magnitude of increase in air conduction at 8000 Hz following surgery regardless of sex (adj. β 2.1, 0.2-4.0 dB per 10-year increase). This is the first study on the interactive effect between patient age and sex with respect to SCD repair outcomes. Older age predicted poorer symptomatic response among female patients but did not predict symptomatic response among male patients. Furthermore, older age predicted more severe high-frequency hearing loss following SCD repairs among both female and male patients. 3 Laryngoscope, 134:3363-3370, 2024.

The Role of Lumbar Drains in the Perioperative Management of Primary Spontaneous Temporal Lobe Encephaloceles and Cerebrospinal Fluid Leaks.

To examine the role of lumbar drains (LDs) in the success of spontaneous temporal cerebrospinal fluid (CSF) leak and encephalocele repair. Retrospective cohort study. Tertiary academic health system. Patients undergoing repair of spontaneous temporal lobe encephaloceles or middle fossa CSF leaks during years 2017 to 2023. Transmastoid, middle fossa craniotomy, or combination approaches to CSF leak repair. Failure rate, complication rate, length of stay (LOS), readmission. Sixty-nine patients were included, with a combination approach performed in 78.3%, transmastoid in 17.4%, and isolated middle fossa craniotomy in 4.3%. Mean body mass index was 33.2, mean bony defect size width was 6.51 mm, and defect locations included the epitympanum, antrum, mastoid, and petrous apex. Multilayer closure with three or more layers was performed in 87.0%. LD was used in 73.9% of cases for a mean duration 2.27 days and was associated with longer LOS (3.27 vs. 1.56 d, p = 0.006) but not with failure rate, complications, discharge destination, or readmission. Only one major complication occurred as a result of the drain, but low-pressure headache was anecdotally common. Use of LD in the repair of spontaneous CSF leaks and temporal lobe encephaloceles is associated with longer LOS but not failure rates or other admission-level outcomes.

Spring-Assisted Surgery of Unilambdoid Craniosynostosis.

Craniosynostosis is traditionally treated with extensive cranial vault reconstructions (CVRs). Although less invasive techniques, such as endoscopic strip craniectomy with postoperative helmet therapy, have been successful, they also present difficulties. An alternative method is distraction osteogenesis using either manually controlled devices or specially designed springs. In this study, the authors provide the first comparison of spring-assisted surgery (SAS) with CVR for the treatment of unilambdoid synostosis (ULS). Fourteen consecutive patients (8 CVR and 6 SAS) treated for ULS at Sahlgrenska University Hospital between 2005 and 2018 were included. Skull shape and deviations were evaluated using previously defined measurement points on 3-dimensional computed tomography scans preoperatively, at spring removal, and at 3 years of age. Posterior and middle cranial fossa (PCF and MCF, respectively), skull-base cant, facial twist, and mastoid bulge (MB) were measured, and clinical data were obtained from chart reviews. The results indicated that at the 3-year follow-up, PCF, MCF, and MB improved in both groups, with no significant difference in outcome observed between methods. In the SAS group, duration of operation [61±27min (mean±SD)] and perioperative bleeding (3.5±2.8mL/kg body weight) were both significantly lower relative to the CVR group (P<0.05). These findings showed that both SAS and CVR resulted in similar improvements in treating ULS, although neither produced complete normalization of skull shape. The results suggest that early diagnosis and operation allow less extensive SAS to be performed without adversely affecting the results.

Reliability of Neuronavigation in Localizing the Internal Acoustic Canal during Middle Fossa Approach

Abstract Objective The absence of precise landmarks in the middle fossa floor and frequent anatomical variations make it difficult to localize the internal acoustic canal (IAC) during the middle fossa approach (MFA). We aimed to investigate the reliability and utility of the neuronavigation system (NNS) in the MFA and to delineate specific technical considerations regarding NNS during the approach. Method One-millimeter-thin section computed tomography scans were performed on five formalin-fixed human cadavers (10 sides). During the MFA, structures, such as the IAC, vestibule and cochlea hidden in the temporal bone were investigated under NNS guidance. Results All the superficial landmarks, such as the foramen spinosum and ovale were correctly localized by NNS. Deeper landmarks, such as the central part of the IAC lying beneath the surface of the petrous apex could not be localized via NNS. The exact area of bone removal along roof of IAC was determined by using the orientation provided by the probe placed between the basal turn of cochlea and the vestibule. We were able to validate the location of the IAC via a medial to lateral drilling by using the navigation this reference point. Conclusion The NNS can be used effectively during the MFA, and localizing superficial landmarks on the middle fossa floor with a higher accuracy may prove helpful in identifying the IAC from above. By referring to the cochlea–vestibule junctional area, the exact location of the trace of the IAC can be revealed.

Fibrous dysplasia of sphenoid wing with secondary aneurysmal bone cyst: a rare case report

BackgroundAn aneurysmal bone cyst is a locally destructive benign lesion affecting mostly the long bones. Aneurysmal bone cyst of the skull bones is a very rare phenomenon and the involvement of the sphenoid bone of the skull with extension into the orbit is even rarer. We present a case of 15-year-old adolescent with fibrous dysplasia of the sphenoid wing with secondary aneurysmal bone cyst.Case presentationA 15-year-old male presented to us with chief complaints of headache with swelling in the left temporal region of the face and proptosis of the left eye associated with decreased vision for the past 2 months. NCCT showed a large heterogeneous mass in the left temporal region extending into left orbit. Gadolinium-enhanced MRI showed a well-defined multiloculated osteo-expansile lesion in the left middle cranial fossa extending into the anterior cranial fossa consistent with the fibrous dysplasia of the sphenoid bone with associated aneurysmal bone cyst. Digital subtraction angiography brain to look for any feeders to the lesion was done followed by microsurgical gross total excision of the tumor. The histopathology report confirmed it to be fibrous dysplasia secondary to aneurysmal bone cyst.ConclusionAneurysmal bone cyst is a rare entity, commonly affecting the long bones of the body. The involvement of sphenoid wing of skull is very rare occurrence. It can be primary or secondary to fibrous dysplasia, chondroblastoma, giant cell tumor, fibromyomas, etc. Fibrous dysplasia with secondary aneurysmal bone cyst should be kept in mind as one of the differential diagnoses while dealing with osteolytic bone lesions of skull.

The historical adventures of Takeshi Kawase: the mountaineer who explored the "no man's land" with love for art, nature, and humankind.

The anterior petrosal approach, or Kawase's approach, is a commonly used technique in skull base surgery to access the brainstem in the posterior fossa from the middle fossa, and has the advantages of minimizing brain retraction and preserving hearing. It was first successfully performed by the legendary Japanese neurosurgeon, Takeshi Kawase, for the clipping of a basilar artery aneurysm in 1981. To date, no historical article has shed light on Kawase's intriguing personal history. In this historical vignette, the authors depict Kawase's unique background, talent, passion, as well as struggles that ultimately shaped his career. By sharing Kawase's personal story from the hospital where he first successfully performed his original approach, the authors hope to pass on to future generations Kawase's spirit and philosophy that have impacted the global neurosurgical community.

Nontraumatic symptomatic de novo arachnoid cyst in an adolescent patient treated with cystoperitoneal shunting: illustrative case.

Arachnoid cysts are often congenital, asymptomatic lesions detected in the pediatric population. When seen in adults, they usually occur following trauma. De novo formation of arachnoid cysts is uncommon, with only a few instances cited in the literature and most of which occurred in the pediatric population. Treatment options for these lesions include observation, craniotomy for cyst resection, microsurgical/endoscopic fenestration, or shunting. In this report, the authors describe a female patient with a de novo, symptomatic, enlarging middle cranial fossa arachnoid cyst detected at age 16 years. She was treated with the placement of a cystoperitoneal shunt. After surgery, she experienced clinical and radiological improvement. We illustrate successful shunting of a de novo arachnoid cyst in a symptomatic teen patient. Although arachnoid cysts in certain intracranial locations are more likely to produce symptoms, those in the middle cranial fossa tend to be asymptomatic. To our knowledge, this is the first reported case of a symptomatic de novo arachnoid cyst located in the middle cranial fossa in a postpubertal patient. Although the current presentation is rare, the authors demonstrate an effective surgical treatment of a symptomatic, large, de novo arachnoid cyst in a postpubertal pediatric patient.

Isolated cerebral varices: clinical observations and literature review

The aim of the study is to present rare clinical cases of isolated cerebral varices, summarize scientific literature data on their diagnosis and treatment.The article describes 2 clinical observations of isolated cerebral varix, presents a literature review of this topic, as well as treatment tactics for patients with this pathology.In the first clinical observation, in a male 72‑year-old patient isolated cerebral varix was interpreted as distal saccular aneurysm of the right middle cerebral artery per computed angiography data. Surgical treatment was performed: from subtemporal approach in the area of the floor of the middle cranial fossa, cerebral varix, inflow and outflow veins were visualized. The inflow and outflow veins were clipped, aneurysm was resected and sent to histological examination. The patient was discharged on day 8 after surgery. Histological examination of the cerebral varix wall showed typical components for a venous wall, in particular, individual smooth muscle fibers, absence of elastic membrane.In the second clinical observation, in a female 59‑year-old patient magnetic resonance (MR) imaging, MR angiography and MR venography in the projection of anterior basal parts of the left temporal area showed an aneurysmal malformation transitioning into the superficial middle cerebral vein. Taking into consideration venous pathogenesis of the vascular lesion, dynamic observation of the patient was chosen.Isolated cerebral varix is a rare vascular pathology without a specific clinical and instrumental picture. To avoid erroneous diagnosis and determine further treatment tactics, additional examinations are recommended: MR imaging, MR angiography and MR venography.

The Basal or Sphenopetrosal Superficial Middle Cerebral Vein Type.

Background and Objectives: The adult superficial middle cerebral vein (SMCV) commonly drains into the middle cranial fossa. However, different embryonic types persist, in which the SMCV drains into the lateral sinus. The basal type of SMCV coursing on the middle fossa floor is a scarce variant. Materials and Methods: During a retrospective study of archived computed tomography angiography (CTA) and magnetic resonance angiography (MRA) files, three rare adult cases of the basal or sphenopetrosal type of SMCV were found and further documented. Results: In the first case, which was evaluated via CTA, the basal type of SMCV formed a sagittal loop. It continued on the middle fossa floor, over a dehiscent tegmen tympani, to drain into the lateral sinus. In the second case, documented via MRA, the basal type of SMCV's anterior loop was in the coronal plane and closely related to the internal carotid artery and the cavernous sinus. It continued with the basal segment over a dehiscent glenoid fossa of the temporomandibular joint (TMJ). In the third case, documented via CTA, the initial cerebral part of the SMCV had a large fenestration. The middle fossa floor coursed within a well-configured sulcus of the SMCV and received a tributary through the tympanic roof. Its terminal had a tentorial course. Conclusions: Beyond the fact that such rare variants of the SMCV can unexpectedly interfere with specific approaches via the middle fossa, dehiscences of the middle fossa floor beneath such variants can determine otic or TMJ symptoms. Possible loops and fenestrations of the SMCV should be considered and documented preoperatively.

Analyzing Foramen Ovale Morphometrically in Adult Dry Skulls of Nigerian-Based Population

Introduction: The foramen ovale is one of the major foramina on the greater wing of the sphenoid that is used for advanced surgical therapeutic and diagnostic procedures pertaining to the middle cranial fossa. The study was aimed at determining the length and width of foramen ovale in a Nigerian population. Materials and Methods: Seven dehydrated adult skulls, all the same gender, were acquired from the anatomy departments of Achievers University in Owo and Delta State University in Abraka, Nigeria. The length and the width of the foramen ovale were measured using digital sliding calipers. The paired sample t-test was used for the analysis. Results: The mean length of the foramen ovale was 0.611±0.21cm on the right side, and 0.42±0.12cm on the left side. The mean width was 0.5±0.15cm on the right side, and 0.43±0.12cm on the left side. Conclusion: Understanding the dimensions of the foramen ovale vary is crucial for neurosurgery during invasive surgical procedures like percutaneous trigeminal rhizotomy, as well as for biopsying Meckel cave lesions and cavernous sinus tumors.

Inner Ear Breaches from Vestibular Schwannoma Surgery: Revisiting the Incidence of Otologic Injury from Retrosigmoid and Middle Cranial Fossa Approaches.

To assess the rate of iatrogenic injury to the inner ear in vestibular schwannoma resections. Retrospective case review. Multiple academic tertiary care hospitals. Patients who underwent retrosigmoid or middle cranial fossa approaches for vestibular schwannoma resection between 1993 and 2015. Diagnostic with therapeutic implications. Drilling breach of the inner ear as confirmed by operative note or postoperative computed tomography (CT). 21.5% of patients undergoing either retrosigmoid or middle fossa approaches to the internal auditory canal were identified with a breach of the vestibulocochlear system. Because of the lack of postoperative CT imaging in this cohort, this is likely an underestimation of the true incidence of inner ear breaches. Of all postoperative CT scans reviewed, 51.8% had an inner ear breach. As there may be bias in patients undergoing postoperative CT, a middle figure based on sensitivity analyses estimates the incidence of inner ear breaches from lateral skull base surgery to be 34.7%. A high percentage of vestibular schwannoma surgeries via retrosigmoid and middle cranial fossa approaches result in drilling breaches of the inner ear. This study reinforces the value of preoperative image analysis for determining risk of inner ear breaches during vestibular schwannoma surgery and the importance of acquiring CT studies postoperatively to evaluate the integrity of the inner ear.

Middle cranial fossa non-cavernous sinus dural arteriovenous fistulas: 20years of experience.

Non-cavernous sinus (CS) dural arteriovenous fistulas (DAVFs) involving the sphenoid bone are rare entities that are easily confused with one another due to the complex structure and high variability of the venous system around the middle cranial fossa. We present a large retrospective study on middle cranial fossa non-CS DAVFs and review the literature on DAVF treatment in this location as well as relative anatomy. 15 patients had DAVFs involving the lesser sphenoid wing and 11 patients had DAVFs involving the greater sphenoid wing. Six patients presented with intracranial hemorrhage or subarachnoid hemorrhage (23.1%, 6/26). The most common symptoms were eye symptoms (38.5%, 10/26). Nineteen patients were treated with trans-arterial embolization (TAE) using liquid embolic agents and two patients were treated with transvenous embolization (TVE) using Onyx or in combination with coils. Surgical disconnection of the drainage veins was performed in five patients, with three cases experiencing unsuccessful TAE. Anatomic cure was achieved in 92.3% of the patients (24/26). Twelve patients had DSA and clinical follow-up from 3 to 27months. There was one recurrence (8.3%) of the fistula in the patient two months after the initial complete occlusion. The majority of patients can be cured endovascularly. Laterocavernous sinus DAVFs may not be embolized by transvenous approach via the cavernous sinus because there is often no connection between them in most patients. A small percentage of patients may require surgical ligation to be cured.

Intracranial meningioma: an unusual silent killer—about two cases report and a literature review

BackgroundMeningiomas are common benign intracranial tumors, accounting for 1/3 of all primary intracranial neoplasms, and hence, are not considered the chief cause of death when encountered incidentally during autopsy. These tumors are usually slow-growing, and the clinical course may be asymptomatic to the point of acute complications. Sudden unexpected deaths due to meningiomas are exceptional and rarely reported in the literature.In the present report, we describe two autopsy cases of sudden unexpected death due to meningiomas and we discuss the mechanism of death.Case presentationTwo apparently healthy men were discovered dead in their home. A judicial autopsy was ordered. At dissection, a pedunculated firm mass, attached to the dura was found in both cases. Tumors were located in the anterior and middle fossa. The remaining organs were congestive without any abnormality. A microscopic examination confirmed the diagnosis of meningiomas. Postmortem toxicology analysis was negative. Forensic pathologists concluded to sudden unexpected death due to intracranial meningioma.ConclusionsThese cases illustrate the possibility of meningioma remaining silent till acute complication and fatal outcome. Therefore, clinicians must bear in mind the possibility, albeit extremely rare, of sudden unexpected death in cases of undiagnosed intracranial meningiomas, as documented in the present report. Thus, we emphasize the value of promptly and thoroughly investigating even seemingly minor neurological symptoms, such as headaches or acute epileptic seizures, in adults. We also stress the importance of the early detection and appropriate management of brain tumors in fatal outcome prevention, and we highlight the role of the post-mortem examination to detect such a fatal complication.

Achieving Cochlear Therapeutic Hypothermia through Irrigation of the Mastoid and Tympanic Cavities

Introduction: Mild therapeutic hypothermia (MTH) is an exciting nonpharmaceutical otoprotection strategy. In this study, we applied simple irrigation of the tympanic and mastoid cavities to understand the timing of both achieving MTH and recovery back to euthermic temperatures for application in the clinical setting. Methods: Three human temporal bones were used in this study in the temporal bone laboratory. A standard mastoidectomy was performed on each followed by the insertion of temperature probes into the basal turn of the cochlea via a middle cranial fossa approach. The temporal bones were warmed in heated bead baths to 37°C. The tympanic and mastoid cavities were then irrigated with room temperature water, and intracochlear temperature readings were recorded every minute. After 15 min, irrigation was stopped, and temperature readings were collected until temporal bones returned to euthermic levels. Results: Intracochlear MTH was achieved within the first minute of irrigating the tympanic and mastoid cavities. Intracochlear temperatures plateaued after 5 min around 30°C. Discontinuation of irrigation resulted in the temperature rising logarithmically above the MTH levels after 9–10 min. Conclusion: Intracochlear MTH can be achieved via irrigation of the tympanic and mastoid cavities with room temperature irrigation within 60 s. After irrigation for 5 min, hypothermic temperatures will remain therapeutic for 10 min following cessation of irrigation.

Principles of diagnosis and treatment of vestibular schwannoma: a literature review

Background. Vestibular schwannoma is a formation of Schwann cells in the vestibulocochlear zone. Despite the benign nature of the tumor, it carries risks for life, as its massiveness poses a threat to intracranial structures and their functional capacity. The purpose of the study is to conduct an analysis of modern information on the diagnosis and methods of treatment of schwannoma. Materials and methods. A literature search using keywords was conducted in Web of Science, Scopus, PubMed, Elsevier, and Springer databases. Results. In most cases, vestibular schwannoma is diagnosed after a number of symptoms are detected such as dizziness, hearing loss, etc. According to modern research, magnetic resonance imaging and audiogram are the most informative and at the same time gold standard for diagnosis, and verification is carried out based on pathohistology. Most schwannomas are clinically stable; however, when analyzing the information, the main approaches in the presence of such a diagnosis were determined. The safest and most non-invasive one is observation, with control of the dynamics of the clinical picture and the size of the formation. However, there are several surgical techniques for complete tumor removal. The most common of them is access through the middle cranial fossa, which, unfortunately, has several limitations. Translabyrinthine and retrosigmoid approaches are also used. The choice of treatment depends on the size, growth and symptoms of the patients. Radiotherapy is one of the relatively new methods of treatment, it is sometimes combined with a surgery. Conclusions. Thus, vestibular schwannoma requires active monitoring and the use of other treatment methods. In the presence of clinical indications, a combination of different types of treatment allows achieving positive therapeutic outcomes. A perspective for future research is the study of targeted gene therapy.

Short Postoperative Length of Stay After Lateral Cerebrospinal Fluid Leak Repair.

To characterize the short-term outcomes of patients undergoing surgical repair of lateral skull base cerebrospinal fluid (CSF) leaks followed by a shortened length of stay (LOS) protocol. Retrospective study. Tertiary medical center. Atotal of 156 adult patients from July 2016 to December 2022 who underwent repair of CSF leaks via transmastoid (TM), middle cranial fossa (MCF), or combined (TM/MCF) approaches were included. Data collected included: LOS, presentation to the emergency department (ED), need for readmission, major neurologic complications (stroke, seizure, and meningitis), and CSF leak recurrence. Approximately half of patients underwent a TM repair (49.4%), whereas the other half underwent either an MCF (3.8%) or combined TM/MCF repair (46.8%). No peri-/postoperative lumbar drains were used and only 2 (1.3%) patients were admitted to the intensive care unit after surgery. Mean LOS for the cohort was 1.1 ± 0.7 days and was longer for surgeries involving MCF (1.3 ± 0.6) compared to TM (0.8 ± 0.7). Ninety-two percent of TM cases were discharged within 24hours (32% on the same day) while for cases involving an MCF approach, 72.2% of patients were discharged within 24hours. Of the patients in the study, 6 (3.8%) presented to an ED for minor complications and no patient required readmission. Revision surgery was required for 3 (1.9%) patients for recurrent CSF leak. Our findings suggest that short LOS after surgical repair of lateral skull base defects in the treatment of CSF leak is safe and effective.