Skull Base Research Articles

Upright CT-based evaluation of the effects of posture on skull-base reconstruction after endoscopic endonasal surgery.

Cerebrospinal fluid (CSF) leakage is a common complication associated with endoscopic endonasal skull-base surgery (EESBS). Postoperative mobilization-associated postural changes are considered to cause CSF leakage. However, no study has demonstrated a robust relationship between postural changes and CSF leakage. We used upright computed tomography (CT) to clarify the effects of postural changes on the reconstructed skull base (RSB) after EESBS. Thirty patients who underwent EESBS at our institution were prospectively included, and their upright and supine CTs were compared to measure morphological changes in the RSB. Patient clinical data were also collected from medical charts and surgical videos, and their relationships with morphological changes were assessed. In upright CTs, the RSB shifted intracranially by 0.94 (0.0-2.9) mm on average. This shift was larger in cases with lesions extending to the sphenoid sinus, dural defects, intraoperative pulsation of the RSB, and large bone windows. The direction of the change was opposite to intuitive movement driven by gravity because of reduced intracranial pressure in the sitting position. Thus, these shifts can be directly associated with postoperative CSF leakage caused by reconstruction material displacement. Skull-base reconstruction and postoperative postural management accounting for these morphological changes may be necessary for preventing CSF leakage.

A single-center experience of the upright proton therapy for skull-base chordomas and chondrosarcomas: Updated results

AimTo access efficacy and safety of the upright proton therapy for the skull-base chordomas and chondrosarcomas. Materials and methodsThe study encompasses single-center experience of proton therapy in chordomas (CA) and chondrosarcomas (CSA) of skull-base localization. We evaluate overall survival, local control and toxicity. Tumor response was assessed in accordance with RANO criteria. Treatment-related toxicity was evaluated with the help of CTCAE v 5.0 scale. ResultsProton therapy in the upright position was utilized for 51pts (patients) with CA-CSA (40 pts with chordoma and 11pts with chondrosarcoma) at the A. Tsyb Medical Radiological Research Center in 2016–2023. Median tumor volume constituted 30 cm3 (IQR (interquartile range) 15–41 cm3). Median total dose was 70 GyRBE. Median number of fractions was 35. Overall survival (OS) at 1-, 2- and 3-year rates reached 98.0 %, 88.6 % and 82.7 %, respectively. Median follow-up time was 36 months. The 1-, 2- and 3-year local control (LC) rates constituted, respectively, 98 %, 78.6 % and 66.3 %. Prior surgery showed statistically significant association with better prognosis (p = 0.023). Brainstem-to-tumor dose coverage compromise became the major pattern of LC failure (p = 0.03). The late radiation toxicity reactions included temporal lobe necrosis grade 2 in 2 pts, xerostomia grade 1 in 1pt, radiation cataract grade 2 in 1pt and persistent headache grade 2 in 4 pts. Severe late toxicity reactions were observed in 2 cases (4 %): 1 myelitis grade 3 and brainstem damage grade 5 in 1pt. ConclusionLocal control was achieved in the majority of patients receiving the scanning-beam upright proton therapy for skull-base CA-CSA. The LC rates after a surgery-radiotherapy combination treatment were higher compared with irradiation alone. Pattern of failure is mostly brainstem-tumor dose compromise. The high OS and LC rates were accompanied by low toxicity incidence. Even in complex case of the skull base CA-CSA upright proton therapy shows promising clinical outcomes.

Effect analysis of 847 nasopharyngeal carcinoma cases treated with intensity modulated radiation: Experience and suggestions

ObjectivesTo identify the failure patterns and prognostic factors of nonmetastatic nasopharyngeal carcinoma (NPC) in the intensity-modulated radiotherapy (IMRT) era. MethodsData on 847 patients with newly diagnosed, non-disseminated NPC treated by IMRT between 2012 and 2016 were retrospectively reviewed. Survival outcome, failure patterns and prognosis factors were analyzed. ResultsThe 5-year local relapse-free survival, nodal relapse-free survival, distant metastasis-free survival, disease-free survival, and overall survival rates were 94.3%, 95.3%, 84.8%, 76.5% and 85.7%, respectively. The major local recurrence sites were the nasopharynx (91.5%, 43/47) and skull base (68.1%, 32/47); 39 patients had in-field failures, four had marginal failures, and four had out-field failures. Level IIb (62.2%, 23/37) was the most frequent regional recurrence site, followed by IIa (35.1%, 13/37) and retropharyngeal region (32.4%, 12/37); 35 cases had in-field failure alone, one had out-field failure alone, and one had both in- and out-field failure. TNM stage was the most significant factor for prognosis prediction. 402 (47.5%) patients had acute adverse events of grade 3 or 4; leukopenia (31.5%) and mucositis (26.7%) was the most common hematological and non-hematological event, respectively. Late complications were slight or moderate damages; xerostomia (647/847, 76.4%) and hearing impairment (422/847, 49.8%) remained the most troublesome. ConclusionNPC patients treated with IMRT obtained satisfactory survival outcomes. The key failure pattern was distant metastasis. The main pattern of local–regional failure was in-field failure. Screening high risk patients with distant metastases and optimizing radiotherapy targets should be studied.

CPAP-induced sphenoid sinus pressures after endoscopic sinus surgery.

Positive pressure transmitted from continuous positive airway pressure (CPAP) to the sinuses and skull base in the early post-operative period has not been studied in live subjects and controversy exists in when to restart this post-operatively. This study found that approximately 32.76% and 13.52% of the delivered CPAP pressures reached the post-surgical sphenoid sinus and the mid-nasal cavity, respectively, suggesting that surgical factors such as tissue edema, nasal packing, blood, and nasal secretions may provide a protective effect.

The Development of a Multidisciplinary Skull Base Program in Support of the Military Health System.

The Development of a Multidisciplinary Skull Base Program in Support of the Military Health System.

Early Treatment of Cerebrospinal Fluid Leakage After Traumatic Injury Using Pedicled Autologous Fascia Flap.

This study aims to investigate the efficacy of early intervention in cerebrospinal fluid leakage following traumatic brain injury through the utilization of pedicled autologous fascia flaps. A retrospective case series, spanning from May 2021 to May 2022, analyzed 8 traumatic brain injury cases with concomitant cerebrospinal fluid leakage. Each patient underwent simultaneous brain surgery and transcranial repair of the cerebrospinal fluid leak, employing a pedicled autologous fascia flap. Clinical and imaging data were comprehensively recorded throughout the entire duration of the cases, and patient follow-ups were conducted through outpatient visits and telephone consultations. The study comprised 8 enrolled patients, consisting of 7 males and 1 female, all of whom sustained injuries from traffic accidents. The mean age ranged from 17 to 55 years. Among the patients, three presented with acute epidural hematoma, three with simple concave fractures, and 2 with concave fractures accompanied by brain contusion. Frontal sinus fractures were observed in all cases. All surgical interventions were successful, with no instances of cerebrospinal fluid leakage postoperatively. In addition, none of the patients developed intracranial infections. At the conclusion of the follow-up period, recurrent cerebrospinal fluid leakage was not observed in any of the patients. In cases where surgical intervention is necessary for cerebrospinal fluid leakage resulting from anterior cranial base fractures, the application of pedicled autologous fascia flaps in the acute stage proves effective in repairing leaks at the anterior cranial base. This approach may contribute to a reduction in the incidence of intracranial infections, ultimately yielding satisfactory patient recovery.

Robust IMPT and follow-up toxicity in skull base chordoma and chondrosarcoma-asingle-institution clinical experience.

Chordomas and chondrosarcomas of the skull base are rare, slowly growing malignant bone neoplasms. Despite their radioresistant properties, proton therapy has been successfully used as an adjunct to resection or as adefinitive treatment. Herewith, we present our experience with robustly optimized intensity-modulated proton therapy (IMPT) and related toxicities in skull base chordoma and chondrosarcoma patients treated at HollandPTC, Delft, the Netherlands. Clinical data, treatment plans, and acute toxicities of patients treated between July 2019 and August 2021 were reviewed. CT and 3.0T MRI scans for treatment planning were performed in supine position in athermoplastic mold. In total, 21dose optimization and 28dose evaluation scenarios were simulated. Acute toxicity was scored weekly before and during the treatment according to the CTCAE v4.0. Median follow-up was 35months (range 12-36months). Overall, 9chordoma and 3chondrosarcoma patients with 1-3 resections prior to IMPT were included; 4patients had titanium implants. Brainstem core and surface and spinal cord core and surface were used for nominal plan robust optimization in 11, 10, 8, and 7patients, respectively. Middle ear inflammation, dry mouth, radiation dermatitis, taste disorder, and/or alopecia of grades 1-3 were noted at the end of treatment among 6patients without similar complaints at inclusion; symptoms disappeared 3months following the treatment. Robustly optimized IMPT is clinically feasible as apostoperative treatment for skull base chordoma and chondrosarcoma patients. We observed acceptable early toxicities (grade1-3) that disappeared within the first 3months after irradiation.

Hearing Loss in the Unoperated Ear After High-Speed Drilling in Otologic and Skull Base Surgery.

To evaluate if permanent hearing loss occurred in the unoperated ear of patients undergoing otologic and skull base surgery with high-speed otologic drilling. We retrospectively studied 250 patients (mean age 57.8 yr; 120 males, and 130 females) undergoing otologic or skull base surgery with high-speed drilling between 2013 and 2019. The University of Pittsburgh Medical Center. We evaluated preoperative and postoperative audiograms for patients undergoing surgery for cochlear implantation (95 patients, 38.0%), cholesteatoma or chronic ear disease (88 patients, 35.2%), repair of lateral skull base encephalocele (26 patients, 10.4%), resection of vestibular schwannoma or meningioma of the cerebellopontine angle (23 patients, 9.2%), lateral temporal bone resection (8 patients, 3.2%), microvascular decompression (7 patients, 2.8%), or other operations involving a high-speed otologic drill (3 patients, 1.2%). Hearing threshold shift, measured as the difference between postoperative threshold and preoperative threshold for each frequency. The association of age, gender, tested frequency, and surgery type with hearing threshold shift was investigated with analysis of covariance. A total of 102 patients (40.8%) had a 10-dB or greater worsening of their hearing in at least one frequency on their postoperative audiogram in the contralateral, unoperated ear. One hundred six subjects (42.4%) had no change in hearing of 10 dB or greater at any frequency. Among patients with longitudinal postoperative audiograms, accelerated age-related hearing loss was observed in low frequencies. A significant number of patients demonstrated poorer hearing thresholds in the contralateral, unoperated ear after otologic and skull base surgery.

Deep learning to predict risk of lateral skull base cerebrospinal fluid leak or encephalocele.

Skull base features, including increased foramen ovale (FO) cross-sectional area, are associated with lateral skull base spontaneous cerebrospinal fluid (sCSF) leak and encephalocele. Manual measurement requires skill in interpreting imaging studies and is time consuming. The goal of this study was to develop a fully automated deep learning method for FO segmentation and to determine the predictive value in identifying patients with sCSF leak or encephalocele. A retrospective cohort study at a tertiary care academic hospital of 34 adults with lateral skull base sCSF leak or encephalocele were compared with 815 control patients from 2013-2021. A convolutional neural network (CNN) was constructed for image segmentation of axial computed tomography (CT) studies. Predicted FO segmentations were compared to manual segmentations, and receiver operating characteristic (ROC) curves were constructed. 295 CTs were used for training and validation of the CNN. A separate dataset of 554 control CTs was matched 5:1 on age and sex with the sCSF leak/encephalocele group. The mean Dice score was 0.81. The sCSF leak/encephalocele group had greater mean (SD) FO cross-sectional area compared to the control group, 29.0 (7.7) mm2 versus 24.3 (7.6) mm2 (P = .002, 95% confidence interval 0.02-0.08). The area under the ROC curve was 0.69. CNNs can be used to segment the cross-sectional area of the FO accurately and efficiently. Used together with other predictors, this method could be used as part of a clinical tool to predict the risk of sCSF leak or encephalocele.

Anatomical Variations of the Jugular Bulb: A Critical and Comprehensive Review

Background and Objectives: The jugular bulb (JB) is the uppermost part of the internal jugular vein receiving the sigmoid sinus. The aim of the present research is to aid the comprehension of the JB, its abnormalities, and surrounding structures for improving both academic and surgical awareness. Materials and Methods: Various studies on this topic were critically reviewed. Cone-beam CT scans and CT and MR angiograms were used to demonstrate each type of the discussed variations. Results: Variations in the JB anatomy were thoroughly documented: high JB, dehiscent JB, hypoplasia and hyperplasia, and diverticula of the JB, as they have significant clinical implications, particularly in the context of otological and neuro-otological surgery, skull base pathology, and diagnostic imaging. Definitions and critical arguments were also specified to clarify existing literature. Additionally, we present a case report illustrating a high and dehiscent JB, an anatomical variation of clinical interest due to its potential for misdiagnosis as a glomus tumor. Another case describes a dehiscent JB with a hypotympanic air cell protruding into it, further highlighting the variability of this condition. Conclusions: It is necessary to proceed with caution when observing abnormal morphological characteristics of the JB. Preoperative assessment of each case is essential for optimal outcomes.

Long-Term Outcomes of Nonsyndromic Isolated Unilateral Lambdoid Craniosynostosis

This study combined qualitative and quantitative approaches to evaluate outcomes of isolated nonsyndromic unilateral lambdoid synostosis at the Children's Hospital of Philadelphia. Volumetric, linear, and angular analyses were performed on long-term postoperative and normal control scans. Preoperative and postoperative clinical photographs were evaluated for the presence of dysmorphic frontofacial features. Among 26 included patients, median age of surgery was 10 months and mean postoperative follow-up was 5.9±5.7 years. Two (7.7%) patients underwent secondary cranial vault procedures. At most recent follow-up, 2 (7.7%) subjects reported intermittent headaches. Twenty (90.9%) of 22 patients were assigned Whitaker grade I. Among 9 subjects with long-term imaging at age 11.5±5.3, posterior vault asymmetry, posterior fossa deflection angle, cranial base angle, and ear position asymmetry all remained greater than in the control group. Of subjects included in the frontofacial feature analysis (n=10), 50% had resolution of all dysmorphic frontofacial features present preoperatively. Overall, most subjects who underwent PVR did not require revisional surgery and had good outcomes both aesthetically and functionally. Despite residual abnormalities in the cranial base and posterior vault, most had resolution of parietal bossing and facial scoliosis. Ear position asymmetry was the most common dysmorphic feature at long-term follow-up.

The validation of morphometric outcomes and stratification system for nonsyndromic sagittal craniosynostosis following total calvarial remodeling

This study aimed to provide an external validation of morphometric outcomes, including recently developed parameters — vertico-longitudinal index (VLI) and vertex-nasion-opisthocranion (VNO) angle — along with a proposed stratification system for nonsyndromic sagittal craniosynostosis (NSC). Thin-cut CT scans performed before and after total calvarial remodeling in 70 NSC children (mean preoperative age, 7.0 months; mean postoperative age 23.8 months) were evaluated. The parameters, including linear dimensions, morphometry-based indices, and cranial angles, were measured at the cranial vault and base. Each patient was also assigned a scaphocephaly severity score (SSS). The obtained data were compared with an age-matched control group of 80 normocephalic children.After surgery, all dimensions of the cranial vault increased, but did not normalize (p < 0.0001). Contrarily, some normalization was noted in the skull base, within the anterior and posterior cranial fossae. Postoperative results confirmed the diagnostic cut-off level for VNO at 50°; however, the proposed VLI cut-offs skewed the accuracy of SSS in the control group.To the best of our knowledge, this study was the first to discuss the value of an NSC stratification system in relation to underlying components. The SSS has a relevant background, but its accuracy would increase with a redefinition of normative VLI ranges.

Posterior clinoid process in children: morphometric analysis, pneumatization ratio, and surgical implications.

To describe pneumatization and topographic position of the posterior clinoid process (PCP) in healthy children when approaching the anterior and middle fossae. The study consisted of computed tomography images of 180 pediatric patients (90 males / 90 females), aged 1-18years. The presence or absence of PCP pneumatization was noted, and the distances of certain landmarks to PCP were measured. The distances of the foramen ovale, foramen rotundum, superior orbital fissure, anterior clinoid process (ACP), foramen magnum and crista galli to PCP were measured as 18.59 ± 3.36mm, 15.37 ± 3.45mm, 14.60 ± 3.05mm, 5.27 ± 3.24mm, 32.03 ± 3.27mm, and 30.45 ± 3.93mm, respectively. These parameters increased with growth (between 1-18years), but the distance between PCP and ACP decreased with an irregular pattern. In 11 sides (3.10%), a fusion between PCP and ACP was determined. PCP pneumatization was identified in 32 sides (8.9%). Its pneumatization correlated with pediatric ages (p < 0.001), but not gender (p = 0.459) or side (p = 0.711). Most of PCP pneumatization appeared after late childhood period (i.e., between 10-18years). Our study provides beneficial data for neurosurgeons to use PCP as a reference point for creating a skull base map in children, because of the incomparable position of PCP in the skull base center.

Three-dimensional anatomical analysis of the optic nerve canal with virtual model based on CBCT

The optic nerve canal (ONC) is a fine skeletal structure that contains the optic nerve. However, it has not been thoroughly examined. This necessitates establishing a baseline knowledge of the geometrical and volumetric parameters of the ONC. The data of twenty patients who received a cone beam computed tomography examination were prepared using a voxel-based segmentation. The measurement was performed separately by two examiners on virtual skull models in stereolithography format in Geomagic Wrap®. The results showed that the volume of the ONC varied between 92.48 mm3 and 162.7 mm3 (M = 123.46 mm3, SD = 26.61 mm3). Sex-specific statistically significant differences in volume were detected only for the right side. The angle of the ONC to the skull base was independent of the diameter of the canal. Both the intrarater and interrater comparisons of the measurements showed high values of reproducibility of the results. This study showed that a virtual anatomical model provides a feasible and reliable method to investigate the ONC. The examination technique could have a wider range of application in anthropology and application in clinical medicine. Advances in the automation of radiological diagnostics and the digital analysis of X-ray images could help to reduce examination times.

Current Indications for Surgical Intervention With Lateral Skull Base Osteomyelitis.

Current Indications for Surgical Intervention With Lateral Skull Base Osteomyelitis.

Long term results with medpor® reconstruction of the anterior skull base at a single institute

Objectives To evaluate a technique of multi-layered CSF repair following endonasal anterior skull base surgery using medpor graft. Design Retrospective review of consecutive case series from a single centre. Subjects 68 cases of repair of CSF leaks utilising medpor identified from a larger prospectively maintained database of endonasal endoscopic procedures at our centre. Methods Retrospective review of a database of consecutive anterior skull base cases from 2016–2022, and further data collection from electronic hospital records. Results During follow up there were 7 cases of post-op CSF leak (10.3%). There were no radiological complications, and no cases of medpor removal or extrusion. Rates of infection were low, there were 3 (4.4%) cases of confirmed bacterial meningitis within our cohort. The mean length of stay was 4.7 days (median 3 days), with 16 cases discharged on the first post-operative day. Conclusions Our experience of using medpor in anterior skull base reconstruction demonstrates that medpor is a readily available, easily handled, and reliable graft option with relatively low rates of infection and post-op CSF leak. Its use reduces the use of autologous graft materials and the associated donor site morbidity. Our long term follow up data further demonstrates the safety and efficacy of this technique.

Conventional Spinal Chordomas: Investigation of SMARCB1/INI1 Protein Expression, Genetic Alterations in SMARCB1 Gene, and Clinicopathological Features in 89 Patients.

The partial loss of SMARCB1/INI1 expression has recently been reported in skull base conventional chordomas, with possible therapeutic implications. We retrospectively analyzed 89 patients with conventional spinal chordomas to investigate the differences in the immunohistochemical expression of SMARCB1/INI1 and the underlying genetic alterations in the SMARCB1 gene. Moreover, we assessed the correlation of clinicopathological features (age, gender, tumor size, tumor location, surgical margins, Ki67 labelling index, SMARCB1/INI1 pattern, previous surgery, previous treatment, type of surgery, and the Charlson Comorbidity Index) with patient survival. Our cohort included 51 males and 38 females, with a median age at diagnosis of 61 years. The median tumor size at presentation was 5.9 cm. The 5-year overall survival (OS) and 5-year disease-free survival (DFS) rates were 90.8% and 54.9%, respectively. Partial SMARCB1/INI1 loss was identified in 37 (41.6%) patients with conventional spinal chordomas (27 mosaic and 10 clonal). The most frequent genetic alteration detected was the monoallelic deletion of a portion of the long arm of chromosome 22, which includes the SMARCB1 gene. Partial loss of SMARCB1/INI1 was correlated with cervical-thoracic-lumbar tumor location (p = 0.033) and inadequate surgical margins (p = 0.007), possibly due to the high degree of tumor invasiveness in this site. Among all the considered clinicopathological features related to patient survival, only tumor location in the sacrococcygeal region and adequate surgical margins positively impacted DFS. In conclusion, partial SMARCB1/INI1 loss, mostly due to 22q deletion, was detected in a significant number of patients with conventional spinal chordomas and was correlated with mobile spine location and inadequate surgical margins.

Traumatic Brain Injury in Admitted Patients with Ocular Trauma

To characterize the epidemiology of simultaneous traumatic brain injury (TBI) and ocular trauma. In this retrospective, observational study, de-identified data from patients admitted with ocular trauma and TBI was extracted from the National Trauma Data Bank (2008-2014) using International Classification of Diseases 9th Revision, Clinical Modification diagnostic codes and E-codes relating to injury circumstances. Mechanisms, types of ocular and head injuries, intention, and demographic distribution were determined. Association of variables was calculated with Student’s t and chi-squared tests and logistic regression analysis. Of 316,485 patients admitted with ocular trauma, 184,124 (58.2%) also had TBI. The mean (standard deviation [SD]) age was 41.8 (23) years. Most were males (69.8%). Race/ethnicity distribution was 68.5% white, 13.3% black, and 11.4% Hispanic patients. The mean (SD) Glasgow Coma Score (GCS) was 12.4 (4.4) and Injury Severity Score (ISS) was 17 (10.6). Frequent injuries were orbital fractures (49.3%) and eye/adnexa contusions (38.3%). Common mechanisms were falls (27.7%) and motor vehicle-occupant (22.6%). Firearm-related trauma (5.2%) had the greatest odds of very severe injury (ISS >24) (odds ratio [OR]: 4.29; p<0.001) and severe TBI (GCS <8) (OR: 5.38; p<0.001). Assault injuries were associated with the greatest odds of mild TBI (OR: 1.36; p<0.001) and self-inflicted injuries with severe TBI (OR: 8.06; p<0.001). Eye/adnexal contusions were most associated with mild TBI (OR: 1.25; p<0.001). Optic nerve/visual pathway injuries had greater odds of severe TBI (OR: 2.91; p<0.001) and mortality (OR: 2.27; p<0.001) than other injuries. Of associated head injuries, the odds of severe TBI were greatest with skull base fractures (OR: 4.07; p<0.001) and mortality with intracerebral hemorrhages (OR: 4.28; p<0.001). Mortality occurred in 5.9% of patients. TBI occurred in nearly two-thirds of ocular trauma admissions. The mortality rate was low with implications for challenging rehabilitation and long-term disability in survivors.

Cardiac Arrest during Temporary Clipping for Ruptured Internal Carotid Artery Aneurysm: A Case Report

Abstract Objectives Mechanical stimulation of the trigeminal nerve during craniofacial, skull base, or dental surgeries may cause bradycardia, hypotension, or cardiac arrest. This phenomenon is called trigeminal cardiac reflex (TCR). We encountered a rare case of a patient who experienced sinus arrest due to temporary clipping of the intracranial carotid artery during the clipping of a ruptured aneurysm. We discuss possible reasons for the occurrence of TCR in this case. Materials and Methods A man in his 30s with no medical history presented with a sudden-onset headache. Computed tomography revealed a subarachnoid hemorrhage in the basal cistern and left Sylvian fissure. Angiography revealed a saccular aneurysm of the left internal carotid-anterior choroidal artery. A left frontotemporal craniotomy and dural incision were performed, followed by a trans-Sylvian approach. Cardiac arrest occurred twice during the temporary clipping of the intracranial carotid artery. After surgery, we performed a cardiac ultrasound echo and a 1-week Holter electrocardiogram. Neither showed abnormalities. No arrhythmia or cardiac events were observed over a one and half-year follow-up period. Results The cardiac arrest might have been triggered by the stimulation of the trigeminal nerve in the internal carotid artery. The repeated and anatomical features of this case suggest that TCR triggered cardiac arrest. Conclusion The high probability that cardiac arrest was induced by trigeminal nerve stimulation should be considered during the temporary clipping of the internal carotid artery. However, the predisposing factors and exact underlying mechanisms for these arrhythmias remain unknown and require further investigation.

Pilot Program in Surgical Anatomy Education for Complex Cranial and Skull Base Procedures: Curriculum Overview and Initial 2-Year Experience at Mayo Clinic

Abstract Background Cadaveric dissection remains a preferred and irreplaceable learning modality among neurosurgery residents. We aimed to develop and describe a tiered, quantifiable, and practical curriculum for cranial neurosurgical anatomy education. We report the structure and evaluation of our 2-year pilot study to serve as a suggested guide for other neurosurgery programs. Methods Our Complex Cranial Dissection Program is tailored to the needs of junior-level neurosurgery residents based on their postgraduation years 1 to 4. Dissections are performed in a sequential manner, each of which emphasize a particular set of manual skills and neuroanatomical knowledge. Dissections are scored on a scale of 10 points. The grading was based on specific landmarks and anatomical structures, which need to be exposed, explored, and preserved. Results Out of 16 residents, 14 individuals (87.5%) attended the dissections in the first iteration of the program and 16 individuals (100%) attended the dissections in the second iteration. A total of 17 dissections were performed across all years. In survey feedback about the program, 100% (Year 1) and 94% (Year 2) of residents considered the assigned dissections to be appropriate for their respective training levels. Further, 100% (Year 1) and 94% (Year 2) of residents endorsed that the dissections were important and helpful for their practice prior to similar operating room experiences. Conclusion The development and implementation of structured dissection programs within residency training, along with dedicated staff, and objective feedback serve a crucial role in neurosurgical education to further develop and enhance surgical skills in the operative setting.