Peris Celda, Maria

BACKGROUND AND OBJECTIVES: Endoscopic transnasal surgery offers a minimally invasive alternative to transcranial approaches for accessing midline skull base lesions involving the petrous apex and petroclival region. However, lateral access, particularly behind the petrous internal carotid artery (ICA), remains limited. The contralateral transmaxillary (CTM) approach provides a more direct surgical trajectory, more parallel to the petrous ICA. Yet, lateral access through this approach can be restricted by anatomic barriers, including the pterygoid process and lateral buttress of the maxillary sinus. We aimed to evaluate the contralateral transmaxillary-transpterygoid (CTMP) approach, with and without the lateral buttress removal (CTMP-LBR), to determine whether these modifications could enhance surgical access to the petroclival region. METHODS: Ten sides from 5 formalin-fixed, latex-injected cadaveric specimens were dissected to compare CTM, CTMP, and CTMP-LBR approaches. Petrous bone drilling was directed posterolaterally behind the petrous ICA toward the region medial to the cochlea. In addition, 30 sides from computed tomography angiography scans were analyzed to obtain radiographic measurements for each approach. RESULTS: Compared with CTM, both CTMP and CTMP-LBR significantly increased access for retrocarotid petrous bone drilling ( P < .001) and yielded a wider surgical angle relative to midline ( P < .001), in both cadaveric and radiographic analyses. In dissections, 20% of sides required CTM only, 50% benefited from CTMP, and 30% required CTMP-LBR to achieve adequate lateral access. Radiographic analysis revealed that CTMP required a median of 4 mm of pterygoid drilling, whereas CTMP-LBR required 9 mm and enabled a trajectory parallel to the petrous ICA with only 11 mm of soft tissue displacement. Patients with smaller angles between the petrous ICA and the horizontal plane were significantly more likely to benefit from CTMP over CTM ( P = .005). CONCLUSION: Modification of the CTM approach with pterygoid drilling and optional LBR improves retrocarotid access. Preoperative evaluation of the petrous ICA angle may help optimize patient-specific planning in endoscopic petroclival surgery.

OBJECTIVE Craniopharyngiomas are challenging lesions, and aggressive resections may cause significant postoperative morbidity and mortality. To mitigate morbidity, a potential strategy of subtotal resection (STR) and adjuvant radiation therapy (RT) has been used, but its impact on survival when compared to gross-total resection (GTR) has been under-investigated. Thus, the objective of this study was to analyze short-term mortality between patients undergoing STR ± RT and GTR, and differences in overall survival (OS) between patients undergoing STR, STR + RT, and GTR in a large, nationally representative database. METHODS The authors queried the National Cancer Database for patients diagnosed with craniopharyngioma between 2004 and 2017. Tumor characteristics, treatment strategies, and extent of resection were analyzed. Endpoints were 3-month mortality rate and OS, which were compared between treatment modalities. Firth’s logistic regression was used to analyze 3-month mortality and was adjusted for age, sex, Charlson Comorbidity Index score, histopathological diagnosis, income quartile, insurance payor, and maximal tumor diameter. Differences in survival between treatment modalities were compared with log time-to-event analyses after excluding deaths occurring within 3 months to control for immortal time bias. RESULTS A total of 1460 adult and 390 pediatric patients were included. Adults undergoing STR ± RT had a lower rate of 3-month mortality compared to those undergoing GTR in adjusted analysis (2.8% vs 4.6%, odds ratio 0.42; p = 0.03). Survival curves for the STR + RT and GTR cohorts did not significantly differ (p = 0.198). A strategy of STR alone showed worse OS compared with GTR and STR + RT (p < 0.01). The average follow-up length for adults was 65.5 months. For pediatric patients, 3-month mortality for those undergoing GTR and STR ± RT was similar (0% vs 1%, respectively; p = 0.33). Additionally, compared to GTR, there were no significant differences in OS between STR + RT (p = 0.41) and STR alone (p = 0.44). The average follow-up length for the pediatric cohort was 79 months. CONCLUSIONS STR + RT was associated with a favorable perioperative mortality profile when compared with GTR and provided similar long-term survival outcomes. Therefore, STR + RT may be considered when GTR carries significant risks.

OBJECTIVE Adamantinomatous craniopharyngioma (ACP) is a rare type of brain tumor that affects a wide age range, from children to older adults. Due to the rarity of the disease, existing studies are predominantly limited to single-center or single-surgeon experiences, often lacking statistical power and generalizability. The aim of this study was to address this gap by providing a comprehensive analysis of ACP outcomes based on a large multicenter cohort from the Registry of Adenomas of the Pituitary and Related Disorders (RAPID). METHODS This multicenter retrospective cohort study was conducted via the RAPID consortium and assessed patients with histologically confirmed ACP treated surgically between August 2000 and November 2024 at high-volume pituitary centers across the United States. RESULTS Among the 359 patients (206 male, median age at primary surgery of 47 years) included in the analysis, 76% underwent endoscopic transsphenoidal surgery and 22% underwent craniotomy. Gross-total resection was achieved in 45% and subtotal resection in 47%. Notably, 120 of 311 patients (39%) presented with preoperative hypothalamic-pituitary axis dysfunction. Following all treatments, permanent hypothyroidism was reported in 40% of patients, adrenal insufficiency in 33%, and arginine vasopressin deficiency in 19%. Of 263 patients who underwent primary surgery, radiation therapy was administered in 84 (32%). Progression-free survival (PFS) declined from 66% at 1 year to 31% at 6 years. In the multivariable analysis, independent predictors of worse PFS included subtotal resection (HR 0.22, 95% CI 0.11–0.42; p = 0.001), partial resection (HR 0.11, 95% CI 0.04–0.28, p = 0.001), larger tumor size (HR 0.77, 95% CI 0.64–0.94; p = 0.009), and tumor extension beyond the sella and suprasellar regions (HR 0.21, 95% CI 0.06–0.74; p = 0.016). Primary surgery and salvage surgery groups showed comparable PFS. CONCLUSIONS In this large multicenter cohort study, gross-total resection was achieved in fewer than half of patients and was independently associated with improved PFS. Approximately one-third of patients underwent radiation therapy after primary surgery. These findings provide robust evidence supporting the prognostic value of extent of resection and inform contemporary treatment algorithms for ACP. The high incidence of postoperative endocrinopathy underscores the need for individualized multidisciplinary long-term care. While the retrospective design is a limitation, the multicenter approach enhances the generalizability of these results.

OBJECTIVE Communicating hydrocephalus may occur following stereotactic radiosurgery (SRS) for vestibular schwannomas (VSs), yet identifying individual patient risk factors associated with this post-SRS complication remains a challenge. This study examined predictors of nonobstructive ventricular enlargement and symptomatic communicating hydrocephalus following primary SRS treatment for VS via a single-center institutional cohort review and meta-analysis of the literature. METHODS A retrospective single-institution cohort study and systematic literature review and meta-analysis examining post-SRS communicating hydrocephalus in VS was performed. RESULTS The institutional cohort consisted of 634 patients who received primary SRS as treatment for VS. The cohort was 51.6% female, with a median age of 64 (range 18–89) years. Following SRS treatment, 364 patients (57.4%) experienced tumor shrinkage, 218 (34.4%) had no change in the size of their lesion, and 52 (8.2%) experienced tumor growth. Nonobstructive ventricular enlargement was observed in 23 patients (3.6%) following SRS treatment, of whom 9 (39.1%) remained asymptomatic and 14 (60.9%) required placement of a ventriculoperitoneal (VP) shunt, with a median time to shunt placement of 8 months. In the multivariate analysis, patients ≥ 65 years old (p = 0.038), SRS target volume ≥ 5 cm 3 (p < 0.001), maximum SRS dose ≥ 26 Gy (p = 0.015), and tumor growth at the most recent follow-up (p = 0.002) were associated with an increased risk of post-SRS ventricular enlargement. Similarly, patients with older age (p = 0.049), increased SRS target volume (p = 0.002), and tumor growth (p = 0.016) were at an increased risk of symptomatic communicating hydrocephalus requiring VP shunt placement. Twenty-nine studies, including the cohort in this study, met inclusion criteria in the meta-analysis. Of the pooled 7825 patients, the overall incidence of hydrocephalus following SRS was 5%, and a subanalysis of 7081 patients demonstrated the incidence of symptomatic hydrocephalus requiring a VP shunt to be 4%. In this subanalysis, the overall shunting rate in patients who experienced post-SRS ventriculomegaly was 92%. Among individual studies in the literature, increased tumor size was most commonly found to be a statistically significant risk factor for post-SRS hydrocephalus. CONCLUSIONS Approximately 5% of patients may experience nonobstructive ventricular enlargement following primary SRS treatment for VS. However, not all patients may be symptomatic and require shunting. Patients who are older (≥ 65 years), those with larger tumor volumes, and those with post-SRS tumor growth may be at increased risk of communicating hydrocephalus and may benefit from closer clinical monitoring.

OBJECTIVE Lesions of the cerebellopontine angle (CPA) and petroclival region represent a challenging surgical target due to the complex anatomy of the involved neurovascular structures. In this scenario, cranial nerve (CN) VI is particularly exposed to potential injuries due to its deep-seated location and absence of a bony foramen that serves as a reference of its most distal cisternal point, especially when it is encased or displaced by large lesions. This study aimed to provide reliable operative guidance for preventing injuries to CN VI during the retrosigmoid approach to address CPA and petrotentorial lesions. METHODS Four formalin-fixed, latex-injected anatomical specimens were dissected to highlight and investigate the relevant anatomy of the CPA and petroclival region during the retrosigmoid approach. Additionally, 50 sides of noninjected formalin-fixed specimens were dissected for morphometric evaluation. Correlations between the petrotentorial junction (PTJ), porus acusticus (PA), and trigeminal impression (TI) with the entry point of CN VI into Dorello’s canal were evaluated. An illustrative clinical case and a 3D anatomical model generated through the photogrammetry scanning technique were described. RESULTS In the sagittal plane, CN VI entrance into Dorello’s canal was found in a trajectory parallel to the PTJ, passing through the inferior aspect of the PA and 21.5 ± 1.3 mm anteriorly. In the coronal plane, the entry point of CN VI into Dorello’s canal was estimated at 6.2 ± 1.2 mm from the anterior edge of the TI in a trajectory perpendicular to the PTJ in 47 (81%) specimens. CONCLUSIONS The obtained results demonstrated two surgical strategies to locate Dorello’s canal within the retrosigmoid route: 1) approximately 20 mm anterior along the inferior edge of the PA parallel to the PTJ; and 2) approximately 6 mm inferior to the anterior edge of the TI, perpendicular to the PTJ. The defined operative strategies provide reliable anatomical guidance to locate the entrance of CN VI into Dorello’s canal within the retrosigmoid route, potentially reducing the risk of abducens nerve palsy and improving patient outcomes.

BACKGROUND Glossopharyngeal neuralgia (GPN) is a rare disorder characterized by severe, episodic pain along the sensory distribution of cranial nerve (CN) IX. Bilateral GPN presents unique challenges for consideration of microsurgical treatment due to potential risks of postoperative dysphagia and cardiac arrhythmias associated with resection of bilateral CN IX/X. Here, the authors describe successful staged bilateral microsurgical rhizotomy of CN IX and upper CN X rootlets to treat bilateral GPN. OBSERVATIONS A 54-year-old female presented with right GPN and underwent a right retrosigmoid craniotomy with rhizotomy, resulting in complete resolution of pain. During the following year, the patient developed left GPN and was considered for the same surgical intervention. However, prior to pursuing surgical intervention, evaluation of her swallowing function was conducted to stratify her risk of pharyngeal sensory denervation or dysphagia, and to confirm her suitability for left-sided rhizotomy. Given the patient’s normal oropharyngeal swallowing function on videofluoroscopic swallow study, she underwent left retrosigmoid craniotomy with rhizotomy. At the 3-month follow-up, the patient described complete resolution of pain and normal swallowing function. LESSONS With the use of comprehensive patient evaluation between surgical stages, staged bilateral microsurgical rhizotomy is a feasible and safe treatment option for carefully selected patients with bilateral GPN. https://thejns.org/doi/10.3171/CASE25359

Summary: Anatomy is a critical component of surgical training; however, traditional resources—such as Netter’s Surgical Anatomy , Gray’s Anatomy , and anatomy applications—often fall short in delivering surgically relevant, 3-dimensional (3D) perspectives of facial anatomy. Although cadaveric dissection remains a valuable teaching tool, its accessibility is limited by cost, ethical concerns, and the lack of structured curricula, making it less feasible for ongoing surgical education. To address these limitations, this article introduced a novel educational approach that integrates 3D photogrammetry and virtual reality technology into the surgical anatomy curriculum for craniofacial and aesthetic surgery. Six fresh cadaveric specimens were meticulously dissected by a plastic surgeon to illustrate the intricate layered anatomy of the face and neck. At each stage of the dissection, a photogrammetry technique was used to capture 360-degree images using 5 digital single-lens reflex cameras alongside a 3D handheld camera. This approach not only ensured high-quality imaging but also facilitated the creation of detailed, lifelike virtual 3D models, enhancing the understanding of facial and neck anatomy within a surgical context. Additionally, we present some technical refinements of the 3D volume renderings to capture precise anatomical details during our dissections. Preliminary results from the use of this technology in anatomy courses and workshops indicated trainee engagement, a clearer grasp of the spatial anatomical relationships, and greater confidence in applying this knowledge to hands-on surgical procedures.

OBJECTIVE Calcium phosphate cement (CPC) use has been previously described as a strategy to reduce the rates of pseudomeningocele and CSF leakage following skull base surgery. The authors aimed to present their institutional experience with CPC in retrosigmoid craniotomy and perform a systematic review of the literature to determine the effectiveness of CPC in reducing postoperative complications, including pseudomeningocele and craniotomy-site CSF leakage. METHODS A retrospective single-institution cohort study of patients who underwent retrosigmoid craniotomy with and without CPC cranioplasty from January 2017 to April 2024 was performed. A systematic literature review and meta-analysis of CPC use in retrosigmoid craniotomy was also performed. RESULTS Of 336 patients who underwent retrosigmoid craniotomy, 193 (57%) were female and the median age at surgery was 55 years (range 18–81 years). The median follow-up duration was 23 months (range 3–80 months). CPC was used to seal the edge of the craniotomy in 66 patients (20%). Among all patients, 50 (15%) experienced a postoperative complication, and 28 (8%) were wound-specific complications. Patients in the non-CPC group experienced significantly more postoperative wound-specific complications than those in the CPC group (10% vs 0%, p = 0.002). Specifically, pseudomeningocele occurred in 0 patients (0%) in the CPC group compared with 24 patients (9%) in the non-CPC group (p = 0.006), which progressed to CSF leaks at the craniotomy site in 6 patients (p = 0.60). Additionally, no patients (0%) in the CPC group experienced wound infection, dehiscence, or breakdown compared with 10 patients (4%) in the non-CPC group (p = 0.22). Five patients (8%) in the CPC group reported prolonged mild incisional pain at the craniotomy site, and there were no instances of major complications related to the CPC. In the meta-analysis, 10 studies met the inclusion criteria, yielding a total of 2166 patients (including the current study), 1101 of whom received CPC. In the pooled analysis, CPC was significantly associated with lower risk of CSF leakage at the craniotomy site (OR 0.23, 95% CI 0.13–0.42; p < 0.01) and lower risk of infection (OR 0.17, 95% CI 0.08–0.38; p < 0.01). CONCLUSIONS CPC use in retrosigmoid craniotomies could be a safe and effective strategy to reduce the incidence of pseudomeningocele and craniotomy-site CSF leakage, leading to lower rates of wound-related complications and infection.

OBJECTIVE In this study, the authors aimed to establish a supervised machine learning (ML) model based on multiple tree-based algorithms to predict long-term biochemical outcomes and intervention-free survival (IFS) after endonasal transsphenoidal surgery (ETS) in patients with Cushing’s disease (CD). METHODS The medical records of patients who underwent ETS for CD between 2013 and 2023 were reviewed. Data were collected on the patient’s baseline characteristics, intervention details, histopathology, surgical outcomes, and postoperative endocrine functions. The study’s primary outcome was IFS, and the therapeutic outcomes were labeled as "under control" or "treatment failure," depending on whether additional therapeutic interventions after primary ETS were required. The decision tree and random forest classifiers were trained and tested to predict long-term IFS based on unseen data, using an 80/20 cohort split. RESULTS Data from 150 patients, with a median follow-up period of 56 months, were extracted. In the cohort, 42 (28%) patients required additional intervention for persistent or recurrent CD. Consequently, the IFS rates following ETS alone were 83% at 3 years and 78% at 5 years. Multivariable Cox proportional hazards analysis demonstrated that a smaller tumor diameter that could be detected by MRI (hazard ratio 0.95, 95% CI 0.90–0.99; p = 0.047) was significantly associated with greater IFS. However, the lack of tumor detection on MRI was a poor predictor. The ML-based model using a decision tree model displayed 91% accuracy (95% CI 0.70–0.94, sensitivity 87.0%, specificity 89.0%) in predicting IFS in the unseen test dataset. Random forest analysis revealed that tumor size (mean minimal depth 1.67), Knosp grade (1.75), patient age (1.80), and BMI (1.99) were the four most significant predictors of long-term IFS. CONCLUSIONS The ML algorithm could predict long-term postoperative endocrinological remission in CD with high accuracy, indicating that prognosis may vary not only with previously reported factors such as tumor size, Knosp grade, gross-total resection, and patient age but also with BMI. The decision tree flowchart could potentially stratify patients with CD before ETS, allowing for the selection of personalized treatment options and thereby assisting in determining treatment plans for these patients. This ML model may lead to a deeper understanding of the complex mechanisms of CD by uncovering patterns embedded within the data.