Multiple myeloma in a young female presenting as an aggressive skull-base tumour.

Plasma cell neoplasia has a wide presentation of disease (localised or systemic) according to the International Myeloma Working Group. Radiological imaging identifies plasmacytomas as solitary lesions or part of multiple myeloma. We present a rare case of a 21-year-old female who presented with a skull-base tumour. Contribution: A head and neck plasmacytoma with further lytic bone lesions was confirmed on imaging. This article presents and discusses the clinical, CT, MRI, positron emission tomography (PET)-CT, histology and laboratory findings.

Radiological Features of Extramedullary Hematopoiesis in a Young Male With Beta-Thalassemia: A Case Report.

The formation of the blood elements and their maturation is called hematopoiesis. In adults, this typically takes place in the bone marrow of vertebrae, ribs, and long bones. In contrast, during fetal development, the primary sites of hematopoiesis are the spleen, liver, and the yolk sac. This process of hematopoiesis, when it occurs in sites other than the bone marrow, is called the extramedullary hematopoiesis (EMH). Extramedullary hematopoiesis usually happens in patients with blood disorders like sickle cell disease and thalassemia, where there is failure of hematopoiesis in the primary sites. Here, we present a young male with beta-thalassemia who presented with shortness of breath and palpitations for one month. This manuscript discusses the imaging findings of the EMH in our patient.

Oncological outcomes of partial thickness calvarial resection for locally advanced scalp malignancies.

OBJECTIVE: Traditionally, locally advanced scalp malignancies have been managed through composite, full-thickness calvarial resection. The aim of this study is to explore the oncologic outcomes of partial calvarial resection for locally invasive scalp malignancies without medullary space invasion, employing a burr-down approach. STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. METHODS: This study analyzed records of 26 adult patients diagnosed with scalp cancer that spread to the calvarial region. Data collected included demographics, medical history, adjuvant therapy details, imaging, surgical outcomes, and postoperative oncological results. RESULTS: 26 patients with cancerous scalp lesions necessitating calvarial resection for deep margin control were identified in 22 men and 4 women. Mean age at diagnosis was 72.7 years. The most common histopathological diagnosis was Squamous cell carcinoma (n = 16). Partial removal of the calvarial lesions was achieved in all patients without any intraoperative complications. Twelve patients received adjuvant therapy consisting of the following modalities: radiation (6), chemotherapy (1), immunotherapy (1), a combination of immunotherapy and radiation (2), and a combination of chemotherapy and radiotherapy (2). There was a total of 7 recurrences: local (n = 3,11.5 %), regional (n = 3,11.5 %), distal (n = 1,3.8 %). Long term local control was achieved in (n = 23,88.4 %) of patients. The mean time of follow-up was 19.1 months, and the mean time to recurrence was 15.1 months. CONCLUSION: Partial calvarial resection represents a viable, safe, and effective surgical technique for cancerous tissue removal, reducing risks associated with full thickness calvarial resection, and enhancing soft tissue healing when compared to the established gold standard.

Endonasal endoscopic or endoscopic-assisted transcranial surgery of Rathke's cleft cysts: does the approach and surgical technique influence the radicality and recurrence rate?

OBJECTIVE: Resections of symptomatic Rathke's cleft cysts (RCCs) are mainly performed via an endonasal transsphenoidal approach. However, there is a lack of equivalent data in current literature concerning transcranial keyhole approach in the treatment of RCCs. In order to find general recommendations for the surgical treatment of RCCs also with regard to recurrence, the object of this study is the analysis and comparison of both techniques. METHODS: Twenty-nine patients having been surgically treated between January 2004 and August 2019 were retrospectively analysed. The transsphenoidal approach was chosen in 16 cases and the transcranial keyhole approach in 13 cases. Both surgical techniques were analyzed and compared concerning preoperative symptoms and cyst characteristics, complications, surgical radicality, endocrinological and ophthalmological outcome and recurrences in patients´ follow up. RESULTS: The postoperative outcome of both techniques was identic and showed highly satisfying success rates with 92% for neurological deficits, 82% for endocrinological dysfunctions and 86% for visual deficits. In contrast, momentous postoperative complications were significantly more likely after transsphenoidal operations. After a mean follow-up time of 5.7 years, the recurrence rates of both cohorts were the same with 0% each. CONCLUSIONS: Regarding its equal outcome with its lower complication rate, the authors suggest using the supraorbital keyhole approach for RCCs whose anatomical configuration allow both techniques. Yet, the decision should always consider the surgeon's personal experience and other individual patient characteristics. Further studies with higher numbers of cases and longer follow-up periods are necessary to analyse the effect of the selected approach on recurrence.

Assessment of differences in mechanical properties and thickness of temporal and occipital bones and correlation with age in Japanese forensic samples.

The mechanical properties and thickness of adult temporal and occipital bones were examined in modern Japanese forensic samples. Cranial bones were obtained from 293 Japanese corpses (179 men and 114 women). During autopsy, left temporal (LT), right temporal (RT), and occipital (O) bone samples were extracted from each skull. Sample thickness (ST) was measured using multidetector computed tomographic imaging. The fracture load (FL) of each sample was measured by a bending test, in which the flexural strength (FS) was calculated. The FL and ST values for O were significantly greater compared with those of the LT and RT bones. The temporal bones were thinner compared with other parts of the skull and at greater risk for fracture. There is a need to take precautions to prevent temporal bone fractures. There were no significant differences in any of the values between LT and RT, indicating bilateral symmetry of the temporal bones. There were significant negative correlations between age and the FL and FS values for all sites in both sexes, except for O in the male samples, suggesting that older individuals are at increased risk for fractures. No significant correlations were observed between age and ST values in any of the samples. There were significantly positive correlations between FL and ST values at all sites regardless of sex.

MRI of a presumptive intracranial histiocytic sarcoma with extracranial extension in a cat.

Case summary: A 4-year-old female neutered Scottish Fold shorthair cat was presented for further investigation of circling towards the right. MRI of the brain revealed an extensive, right-sided temporal muscle lesion with associated frontotemporal bone osteolysis, intracranial, extra-axial extension along the calvarial convexity with severe pachy- and leptomeningeal thickening and contrast enhancement, and an intra-axial space-occupying lesion in the right piriform lobe. The regional lymph nodes were moderately enlarged. Cytology of the right parotid lymph node and the temporal muscle was performed and histiocytic sarcoma (HS) was diagnosed. The owners elected euthanasia. Relevance and novel information: HS of the central nervous system (CNS) is a very rare neoplastic condition in cats. Although a few case reports mention MRI, to our knowledge, the characterisation of MRI features of feline CNS HS have not been investigated in detail. Therefore, the aim of this case report was to describe the MRI characteristics in a feline HS involving not only the CNS, but also the fronto-temporal bone, temporal muscle and the regional lymph nodes. In particular, aggressive neoplastic bone invasion was a novel finding.

Multidisciplinary approach to severe intracranial, intraorbital allergic fungal sinusitis.

BACKGROUND: Allergic fungal sinusitis (AFS) is a form of paranasal mycosis that often involves bone destruction and can extend into the orbit and anterior skull base. Intracranial and intraorbital involvement are published but not both in each included patient of a series. The purpose of the present study was to review cases of extensive AFS with orbital or/and skull base erosion, including the presenting symptoms, patient socioeconomic background, imaging features, surgical technique, and post-operative outcomes. METHODS: The records of 30 patients with the histological diagnosis of AFS and both intracranial and intraorbital involvement were reviewed. RESULTS: The average age of the patients was 25.2 years. 83 % of patients were male. 70 % were African American. 66 % of patients had Medicaid or were uninsured. Presenting symptoms were headaches (80 %), nasal obstruction (33 %), proptosis (40 %), vision change (23 %), facial pressure (10 %), and decreased sense of smell (7 %). 100 % of patients had bone erosion observed on computerized tomography scans with disease extending intracranially through the anterior skull base or posterior wall of the frontal sinus along with disease that eroded through the lamina papyracea. All patients had failed medical management. All patients underwent surgery by Otolaryngology, Ophthalmology, and Neurosurgery with transnasal endoscopic approaches and orbitotomy. 80 % also underwent a bifrontal craniotomy for removal of intracranial extradural disease with cranialization. 53 % of patients had orbital implants remaining after surgery; 23 % had nasal stents. There were no postoperative cerebrospinal fluid leaks. Average hospital stay was 4.8 days. Preoperatively, 13 % of patients underwent allergy testing. 94 % saw an Allergist postoperatively. 21 % required follow up surgery. CONCLUSIONS: A team approach of Otolaryngologists, Ophthalmologists, and Neurosurgeons is recommended for this slowly growing but locally destructive disease. Most patients with AFS will present with headaches and nasal obstruction. While most cases of AFS can be successfully managed with transnasal endoscopic techniques, orbitotomy and craniotomy represents an effective treatment for severe AFS cases with extensive intracranial and intraorbital involvement. This disease is found most commonly in young African American males and in the underinsured.

Unveiling primary intracranial eosinophilic angiocentric fibrosis: A rare case report and diagnostic dilemmas.

Eosinophilic angiocentric fibrosis (EAF) is a rare, benign fibroinflammatory condition primarily affecting the sinonasal and upper respiratory tract, with a few cases reported beyond these regions. Primary intracranial EAF is rare. To date, only one case of intracranial EAF has been reported; ours is the second. This case report presents a case of EAF in a 55-year-old man, initially misdiagnosed as meningioma based on clinical and radiological features. The patient complained of a persistent dull headache for six months without associated neurological symptoms. Brain magnetic resonance imaging revealed a dural-based lesion with characteristics suggestive of meningioma. However, histopathological examination post-surgical resection revealed a nodular vascular lesion with concentric angiocentric fibrosis, a distinctive onion skin pattern, and an inflammatory infiltrate rich in eosinophils, plasma cells, and histiocytes. Immunohistochemistry ruled out IgG4-related disease, and other systemic disorders were ruled out based on combined clinical and histological features. This case underscores the need for considering EAF in the differential diagnosis of dural-based lesions. Awareness of its potential mimicking of meningioma is crucial for accurate diagnosis and appropriate management, emphasizing the importance of histopathological examination in challenging cases.

Application of Computerized Surgical Planning in Craniosynostosis Surgery.

Craniosynostosis, a medical condition characterized by premature fusion of one or multiple cranial sutures, has historically been treated through surgical correction. Computerized Surgical Planning (CSP) and three-dimensional (3D) modeling have gained significant popularity across craniofacial surgery. Through a collaborative effort between surgeons and engineers, it is now possible to virtually execute a surgical plan based on preoperative imaging using computed tomography scans. The CSP workflow involves several elements including virtual 3D modeling, CSP computer-aided surgical guide design, manufacturing of guides and templates, and intraoperative implementation. Through the gradual optimization of this workflow, it has been possible to achieve significant progress in the surgical process including improvements in the preoperative planning of complex craniosynostosis cases and reduction of intraoperative time. Furthermore, CSP and 3D modeling have had a positive impact on surgical simulation and residency training, along with patient education and counseling. This article summarizes the CSP workflow in the treatment of craniosynostosis and the implications of this treatment modality on medical trainee education and patient management.

Indications, operative techniques, and outcomes of occipital artery-vertebral artery bypass: an institutional series.

PURPOSE: Posterior circulation cerebral bypasses often show higher risks and lower patency. Only few reports discussed occipital artery (OA)-vertebral artery (VA) bypasses. We present our illustrative cases to address current gaps in the literature on OA-VA bypass. METHODS: A single-center retrospective review was conducted to include all institutional cases of OA-VA bypass, discussing the technique and outcomes. RESULTS: Four institutional cases undergoing a total of 5 bypasses were evaluated, including 3 males and 1 female, with median age of 65 years (range, 62-73). All patients had vertebrobasilar insufficiency (VBI) with recurrent strokes/TIAs due to intracranial atherosclerosis, leading to unilateral VA stenosis with contralateral occlusion (1, 25%), bilateral VA stenosis (1, 25%) or occlusion (1, 25%). Medical management included aspirin for all cases (100%), with clopidogrel in 3 (75%). Surgery was performed through a far lateral approach, connecting the OA to the VA-3 segment, with no inter-positional graft. One patient underwent contralateral OA-VA bypass 6 months after the prior surgery due to worsening of the contralateral VA stenosis. Bypass patency was confirmed in all cases with post-operative angiography. All patients had clinical improvement, with one case of wound dehiscence managed conservatively. All patients were alive at last follow-up (median 7.0 months; range: 1.5-18). CONCLUSION: OA-VA bypass is a challenging yet effective strategy in selected patients with VBI. Current literature lacks unique definitions of surgical indications and techniques, which we addressed in our series. Surgical education should focus on expanding the microsurgery anatomy knowledge.

Intraoperative surgical navigation as a precision medicine tool in sinonasal and craniofacial oncologic surgery.

INTRODUCTION: Recent evidence supports the efficacy of surgical navigation (SN) in improving outcomes of sinonasal and craniofacial oncologic surgery. This study aims to demonstrate the utility of SN as a tool for integrating surgical, radiologic, and pathologic information. Additionally, a system for recording and mapping biopsy samples has been devised to facilitate sharing of spatial information. MATERIALS AND METHODS: SN was utilized for biopsy mapping in 10 sinonasal/craniofacial oncologic procedures. Twenty-five raters with experience in anterior skull base oncology were interviewed to identify 15 anatomical structures in preoperative imaging, relying on topographical descriptions and surgical video clips. The difference in the localization of anatomical structures by raters was analyzed, using the SN-mapped coordinates as a reference (this difference was defined as spatial error). RESULTS: The analysis revealed an average spatial error of 9.0 mm (95 % confidence interval: 8.3-9.6 mm), with significant differences between surgeons and radiation oncologists (7.9 mm vs 12.5 mm, respectively, p < 0.0001). The proposed model for transferring SN-mapped coordinates can serve as a tool for consultation in multidisciplinary discussions and radiotherapy planning. CONCLUSIONS: The current standard method to evaluate disease extension and margin status is associated with a spatial error approaching 1 cm, which could affect treatment precision and outcomes. The study emphasizes the potential of SN in increasing spatial precision and information sharing. Further research is needed to incorporate this method into a multidisciplinary workflow and measure its impact on outcomes.

Lateral compartment of the cavernous sinus from the endoscopic endonasal approach: anatomical considerations and surgical relevance to adenoma surgery.

OBJECTIVE: The cavernous sinus (CS) has 4 compartments: superior, inferior, posterior, and lateral. Among these, the lateral compartment is the most common location for residual tumor, given the risk of neurovascular injury. The authors' study aimed to delineate the anatomical landmarks in this area and illustrate the technical nuances of the lateral transcavernous approach. METHODS: Twenty-two colored silicone-injected specimens were dissected via an endoscopic endonasal approach to the lateral compartment of the CS. The anatomical landmarks and the internal carotid artery (ICA) mobilization technique were investigated. Two illustrative cases are provided. RESULTS: The lateral compartment of the CS is bounded by the carotid-oculomotor membrane (COM) and optic strut as the roof and the petrolingual ligament and lingual process as the floor. It is divided into 2 asymmetrical subcompartments: the upper, larger subcompartment, located superior to the abducens nerve, accommodates the lateral parasellar ligament (LPL), inferolateral trunk (ILT), and branches of the tentorial artery; and the lower, smaller subcompartment, inferior to the abducens nerve, accommodates only the sympathetic nerve branches as they join the abducens nerve. The LPL is a well-defined ligamentous band and was identified in 38 (86%) hemispheres with 2 distinct configurations: 1) robust LPL (59%), with highly compacted ligamentous bands tightly adherent to the ICA; and 2) dispersed LPL (27%), with less compaction and adherence to ICA. The main attachment of the LPL to the cavernous ICA was most commonly observed at the horizontal ICA segment (55%), followed by the anterior (18%) and posterior (14%) genua. The ILT, as the main vessel in the lateral compartment, was identified in 41 (93%) hemispheres and originated from the horizontal ICA segment (80%) or the anterior genu (14%), from either the lateral (52%) or inferior (41%) aspect of the cross-section of the ICA. In 64% of hemispheres, the LPL wrapped the ILT, abducens nerve, and sympathetic nerve to form a broad and firm neurovascular-ligamental complex. Transection of the LPL, ILT, and COM enables medial ICA mobilization and enhances access to the lateral compartment of the CS, potentially increasing the exposure width by 6 ± 1 mm. CONCLUSIONS: This study provides valuable insights into the anatomical intricacies of the lateral compartment of the CS and underscores the potential benefits of the endoscopic endonasal lateral transcavernous approach. Further clinical applications are essential for validating these findings and optimizing surgical outcomes.

Sublabial transmaxillary approach to the inferior aspect of the orbit.

OBJECTIVE: The objective was to demonstrate the surgical steps and outcomes of the sublabial transmaxillary microsurgical approach with endoscopic assistance to treat lesions in the inferior aspect of the orbit, as well as to describe the use of patient-specific 3D models to facilitate surgical preparation and improve experience with the technique. METHODS: The authors' study evaluated data from patients who underwent an endoscope-assisted sublabial transmaxillary approach for inferior orbital lesions. For 2 patients, 3D models were created for preoperative planning and assessment of the approach. Surgical steps comprised osteotomy to access the maxillary sinus, bony resection of the orbital floor, opening of the periorbital fascia, and dissecting and removing the lesion, followed by closure. The neuroendoscope was used to inspect the surgical cavity between each step. RESULTS: The study included 5 patients with varying visual field defects and proptosis who underwent the sublabial transmaxillary microsurgical approach with endoscopic assistance. Complete resection was achieved in all, and all patients reported improvement in visual field defects and proptosis after the procedure. No complications were observed except for transient unilateral maxillary edema noted around the incision site in 3 patients during the early postoperative period, which resolved within a few days. Histopathological examination confirmed the diagnosis of cavernous malformation in all patients. CONCLUSIONS: The sublabial transmaxillary approach is a direct and safe method to resect cavernous malformations at the inferior aspect of the orbit. It reduces the risk of complications associated with lateral, transcranial, and transnasal approaches that may cross critical structures. The microsurgical approach provides the benefit of two-handed dissection for lesions embedded in orbital fat, which can be challenging because of adhesions to surrounding tissues. The use of 3D models can facilitate surgical planning and enhance familiarity with the approach.

Delayed facial nerve palsy after vestibular schwannoma resection: risk factors, extent and prognosis.

INTRODUCTION: Facial nerve palsies may develop during the postoperative period of microsurgical removal of vestibular schwannomas (VSs), even after normal facial function for days or weeks after surgery. The aim of this study was to identify the pathomechanism and predictive factors of delayed palsy. MATERIAL AND METHOD: The clinical data of 193 patients who underwent vestibular schwannoma surgery between 2012 and 2021 were retrospectively analyzed. A total of 134 patients were included. The patients showed intact facial nerve function up to 24 h after surgery. All patients (n = 20) with palsy from postoperative day 4 were included and collectively referred to as delayed facial nerve palsy (DFNP). Various factors were checked using a binomial regression analysis. RESULTS: The mean age of patients with DFNP was 57.8 years (55% female, 45% male). 70% had VS with KOOS ≥ 3, and 60% underwent surgery via a translabyrinthine approach Among the 16 patients with DFNP-related neurotropic pathogens, 25% were seropositive for herpes simplex virus. Most patients (n = 9/20) experienced onset of palsy between postoperative days 6 and 10. Of the four variables included in the significance test, three were significant: KOOS ≥ 3 (p < .04), ipsilateral vestibular organ failure (p < .05), and age group (p < .03). After therapy, 100% of patients recovered almost complete facial nerve function. The parameters mentioned above (KOOS classification and ipsilateral vestibular dysfunction) could be proven risk factors for the occurrence of DFNP.

Supraorbital Approaches for Anterior Skull Base and Parasellar Lesions: Insights From a Single-Center Experience.

BACKGROUND: Modern neurosurgery has undergone significant evolution to include minimally invasive procedures, with the supraorbital approach (SOA) being a prime example. In this study, we aim to explore the surgical techniques and outcomes of this approach in the surgical treatment of frontal lobe, anterior skull base, and parasellar lesions. METHODS: This study included 33 patients aged 36-83 years who underwent surgery using the SOA for lesions in the inferior frontal lobe, anterior skull base, and parasellar area between 2015 and 2024. There were 25 cases of meningioma, 2 cases of brain abscess, 2 cases of glioma, and one case each of craniopharyngioma, hemangioma, metastasis, and Rathke's cleft cyst. The medical data and follow-up results were retrospectively analyzed. RESULTS: The mean size of lesion was 3.38±3.05 cm. The mean follow-up period was 48.8 months. Gross total resection was achieved in 25 patients (75.8%). There were no perioperative deaths, cases of cerebrospinal fluid rhinorrhea, or infections. Two cases of morbidity were reported as complications: one case of delayed intracerebral hemorrhage and one case of infarction due to vascular injury. All patients exhibited satisfactory cosmetic results. CONCLUSION: In comparison to the conventional pterional approach, the SOA represents a safe and effective keyhole method for the removal of both extra-axial and intra-axial skull base tumors. This is particularly beneficial for lesions in the orbitofrontal region and parasellar area, as it allows for minimal disruption of normal brain parenchyma. Moreover, the SOA promotes a swift recovery and short hospital stay. Additionally, the SOA yields superior cosmetic results, including the prevention of temporalis muscle atrophy.

Investigating the Life Expectancy at Birth of Companion Dogs in Portugal Using Official National Registry Data.

This study aimed to provide a comprehensive picture of the life expectancy of dogs in Portugal, focusing on the impact of diverse factors including breed, sex, size, and skull shape. The final dataset, gathering data from the national registry database, consisted of 278,116 dogs with confirmed deaths. The mean lifespan at birth for all the dogs was around 8.91 years, with the female dogs tended to have a similar lifespan to male dogs. The analysis of life expectancy at birth for the 20 most common non-Portuguese breeds and 10 Portuguese breeds revealed that Yorkshire Terriers had the highest life expectancy (10.89 years) and French Bulldogs the lowest (6.27 years). Size and cephalic index were found to be influential factors, with large brachycephalic breeds exhibiting shorter life expectancies and smaller, mesocephalic breeds experiencing longer lifespans. Additionally, the cephalic index had a more substantial impact on life expectancy compared to body size. These findings enhance the understanding of the factors influencing canine longevity and aid in developing strategies to improve the health and lifespan of companion dogs.

RS2-Net: An end-to-end deep learning framework for rodent skull stripping in multi-center brain MRI.

Skull stripping is a crucial preprocessing step in magnetic resonance imaging (MRI), where experts manually create brain masks. This labor-intensive process heavily relies on the annotator's expertise, as automation faces challenges such as low tissue contrast, significant variations in image resolution, and blurred boundaries between the brain and surrounding tissues, particularly in rodents. In this study, we have developed a lightweight framework based on Swin-UNETR to automate the skull stripping process in MRI scans of mice and rats. The primary objective of this framework is to eliminate the need for preprocessing, reduce the workload, and provide an out-of-the-box solution capable of adapting to various MRI image resolutions. By employing a lightweight neural network, we aim to lower the performance requirements of the framework. To validate the effectiveness of our approach, we trained and evaluated the network using publicly available multi-center data, encompassing 1,037 rodents and 1,142 images from 89 centers, resulting in a preliminary mean Dice coefficient of 0.9914. The framework, data, and pre-trained models can be found on the following link: https://github.com/VitoLin21/Rodent-Skull-Stripping.

Longitudinal analysis of cranial growth using comprehensive craniometric measurements after fronto-orbital advancement in coronal craniosynostosis.

OBJECTIVE: The objective of this study was to investigate the longitudinal changes in cranial growth following fronto-orbital advancement (FOA) surgery in patients with unilateral and bilateral coronal craniosynostosis. METHODS: This retrospective review analyzed head circumference (HC) and CT data during preoperative (T0), immediate postoperative (T1), and final follow-up (T2) visits in 40 patients (23 female, 17 male) who underwent FOA using either the open approach or distraction osteogenesis (DO) between 1987 and 2018. The mean follow-up period was 90.62 months. The z-scores of HC, CT-based intracranial volume, anteroposterior diameter (APD), biparietal diameter (BPD), and cranial height (CH) were calculated using sex- and age-specific standards. Logistic regression analysis was performed. RESULTS: While the z-scores of HC, intracranial volume, and BPD remained within the normal range, the z-scores of APD fluctuated between -2 and -1, and the z-scores of CH were > 2, indicating a substantial elevation compared with norms from T0 to T2. Age at surgery significantly influenced the z-scores of HC, BPD, and CH at T2 (all p < 0.05). Delayed surgical timing was correlated with increased BPD and CH z-scores from T1 to T2 (p = 0.007 and 0.019, respectively). The DO for FOA resulted in elevated HC z-scores at T2 and increased APD from T0 to T1, followed by a significant APD relapse from T1 to T2. CONCLUSIONS: These findings suggest that delayed surgical timing may support better cranial growth, as indicated by increased HC at long-term follow-up. However, delayed timing is also associated with worsening abnormally elevated CH. Despite the immediate APD expansion and long-term HC increase with DO, potential relapse warrants caution. While intentional overcorrection of APD is recommended, careful consideration of surgical timing and planning is essential.

Patient height and American Society of Anesthesiologists class as significant risk factors for posterior fossa surgery in the semisitting position.

OBJECTIVE: To optimize surgical positioning for posterior fossa surgery (PFS) using the semisitting position (SSP) to avoid venous air embolism (VAE) and its possible life-threatening consequences, the authors evaluated their experiences with the SSP by analyzing a large cohort of PFS patients. METHODS: A retrospective analysis of the charts of 202 consecutive PFS patients (median age 54 years, IQR 41-61 years; 121 females) with various tumor or vascular conditions who underwent surgery in an SSP between 2019 and 2022 was performed. Age, sex, weight, height, BMI, American Society of Anesthesiologists (ASA) class, histology, duration of surgery, and length of hospital stay were assessed. Transesophageal echocardiography was used pre- and intraoperatively to monitor for and assess the degree of VAE. RESULTS: Altogether, VAE occurred in 30 of 202 (14.9%) patients, with clinically relevant VAE occurring in 14 of 202 (7%) patients. The grades of VAE were I, III, and IV in 16 (8%), 4 (2%), and 10 (5%) patients, respectively. Patient height (p = 0.04), ASA class (p = 0.03), and ASA class ≤ II (p = 0.02) remained the only preoperative statistically significant risk factors for intraoperative VAE, with a median height of 178 cm (IQR 172-184 cm) in patients with clinically relevant VAE compared with 170 cm (IQR 164-176 cm) in those without VAE. CONCLUSIONS: In summary, the data demonstrate that SSP can be used safely for PFS when taking special care to optimize positioning in tall and lower-grade ASA patients intraoperatively.