The 100 Most Cited Articles in Endoscopic Endonasal Skull Base Surgery: A Bibliometric Analysis.

BACKGROUND: The accelerated growth of endoscopic endonasal skull base surgery has led to an abundance of highly cited works that have helped shape the field into its current state. Highlighting these works can serve as a guide for trainees and facilitate evidence-based clinical decision making and operative techniques. METHODS: Elsevier's Scopus database was used to generate a list of the 100 most cited articles on endoscopic endonasal skull base surgery in September 2022. Results were categorized based on pathology, approach, study design, and study objective. A citation per year analysis was conducted to highlight later publications that may not have had the time to accumulate as many citations as older publications. RESULTS: The average number of citations for the 100 most cited articles was 210 per article (range 104-1285). Publication dates ranged from 1997 to 2019, with the highest number of articles among the 100 most cited being published in 2008 (15 articles). The journal with the greatest number of publications was Neurosurgery (30 articles). Of the 100 most cited articles, 77 were published between 2000 and 2010. Moreover, 40 of the 100 articles reported surgical outcomes and related complications, and the most common pathology was pituitary adenoma (25 articles). CONCLUSIONS: This article provides a list of highly influential articles in the field of endoscopic endonasal skull base surgery, highlighting its rapid evolution over the last 3 decades and demonstrating its leap from small descriptive series confined to certain pathologies to larger cohorts exploring possible boundaries and other pathologies.

Ultrasound Elastography in Neurosurgery: Current Applications and Future Perspectives.

BACKGROUND: Similar to clinical palpation, Ultrasound elastography (USE) helps distinguish between tissues by providing information on their elasticity. While it has been widely explored and has been applied to many body organs, USE has not been studied as extensively for application in neurosurgery. The current systematic review was performed to identify articles related to the use of interoperative USE in neurosurgery. METHODS: Search included MEDLINE(R) database. Only original peer-reviewed full-text articles were included. No language or publication year restrictions were imposed. Two independent reviewers assessed the search results for relevance. The identified articles were screened by title, abstract, and full-text review. RESULTS: Seventeen articles were included in the qualitative analysis and 13 articles were related to oncology, epilepsy (n = 3), and spine (n = 1). In oncology, USE was found useful in defining tumor stiffness, aiding surgical planning, detecting residual tumors, discriminating between tumor and brain tissue, and differentiating between different tumors. In epilepsy, USE could improve the detection of epileptogenic foci, thereby enhancing the prospect of complete and safe resection. The application in spinal surgery was limited to demonstrating that a compressed spinal cord is stiffer than the decompressed one. CONCLUSIONS: USE was found to be a safe, quick, portable, and economic tool that was a useful intraoperative adjunct to provide information corresponding to a variety of neurosurgical diseases, at different stages of surgery. This review describes the current intraoperative neurosurgical applications of USE, the concept of elasticity, and different USE modalities as well as the technical challenges, limitations, and possible future implications.

Early and isolated breast cancer metastasis to the pituitary: A case report and systematic review.

Background: Pituitary metastases (PMs) arising from breast cancer tend to occur many years following initial diagnosis, and after other systemic metastasis have been identified. Survival is generally considered to be poor. However, there are cases where patients present with an isolated metastatic lesion in the pituitary. Survival in this subset of patients has not been evaluated. We present a case of isolated PM that presented two years after initial diagnosis of breast cancer. We performed a systematic review of 38 breast cancer patients with PM. We report presentation, treatment strategy, and outcomes of breast cancer metastasis to the pituitary and highlight cases of isolated PM. Case Description: A 39 year old female presented with complaints of headache and polydipsia two years after diagnosis with breast cancer. Systemic workup was unremarkable, but brain imaging identified an isolated PM. Transsphenoidal debulking was performed with adjuvant radiation therapy (RT) targeted to the sellar region. Unfortunately, she passed away 9 months later from systemic progression. Conclusion: A total of 38 patients were included systematic review. Of these, 13 had isolated PM. Prevalent signs/ symptoms included visual disturbance, diabetes insipidus (DI), and hypothalamic dysfunction. Patients treated with surgical resection and adjuvant chemotherapy (ChT), or RT had better survival than those treated with resection alone. Patients that receive treatment for isolated PM may survive for many years without progression or recurrence.

Clinical outcomes in pediatric hydrocephalus patients treated with endoscopic third ventriculostomy and choroid plexus cauterization: a systematic review and meta-analysis.

OBJECTIVE: Endoscopic third ventriculostomy and choroid plexus cauterization (ETV+CPC) is a novel procedure for infant hydrocephalus that was developed in sub-Saharan Africa to mitigate the risks associated with permanent implanted shunt hardware. This study summarizes the hydrocephalus literature surrounding the ETV+CPC intraoperative abandonment rate, perioperative mortality rate, cerebrospinal fluid infection rate, and failure rate. METHODS: This systematic review and meta-analysis followed a prespecified protocol and abides by Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive search strategy using MEDLINE, EMBASE, PsychInfo, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Scopus, and Web of Science was conducted from database inception to October 2019. Studies included controlled trials, cohort studies, and case-control studies of patients with hydrocephalus younger than 18 years of age treated with ETV+CPC. Pooled estimates were calculated using DerSimonian and Laird random-effects modeling, and the significance of subgroup analyses was tested using meta-regression. The quality of the pooled outcomes was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. RESULTS: After screening and reviewing 12,321 citations, the authors found 16 articles that met the inclusion criteria. The pooled estimate for the ETV+CPC failure rate was 0.44 (95% CI 0.37-0.51). Subgroup analysis by geographic income level showed statistical significance (p < 0.01), with lower-middle-income countries having a lower failure rate (0.32, 95% CI 0.28-0.36) than high-income countries (0.53, 95% CI 0.47-0.60). No difference in failure rate was found between hydrocephalus etiology (p = 0.09) or definition of failure (p = 0.24). The pooled estimate for perioperative mortality rate (n = 7 studies) was 0.001 (95% CI 0.00-0.004), the intraoperative abandonment rate (n = 5 studies) was 0.04 (95% CI 0.01-0.08), and the postoperative CSF infection rate (n = 5 studies) was 0.0004 (95% CI 0.00-0.003). All pooled outcomes were found to be low-quality evidence. CONCLUSIONS: This systematic review and meta-analysis provides the most comprehensive pooled estimate for the ETV+CPC failure rate to date and demonstrates, for the first time, a statistically significant difference in failure rate by geographic income level. It also provides the first reported pooled estimates for the risk of ETV+CPC perioperative mortality, intraoperative abandonment, and CSF infection. The low quality of this evidence highlights the need for further research to improve the understanding of these critical clinical outcomes and their relevant explanatory variables and thus to appreciate which patients may benefit most from an ETV+CPC. Systematic review registration no.: CRD42020160149 (https://www.crd.york.ac.uk/prospero/).

Tool-Tissue Forces in Hemangioblastoma Surgery.

OBJECTIVE: Surgical resection of intracranial hemangioblastoma poses technical challenges that may be difficult to impart to trainees. Here, we introduce knowledge of tool-tissue forces in Newton (N), observed during hemangioblastoma surgery. METHODS: Seven surgeons (2 groups: trainees and mentor), with mentor (n = 1) and trainees (n = 6, PGY 1-6 including clinical fellowship), participated in 6 intracranial hemangioblastoma surgeries. Using sensorized bipolar forceps, we evaluated tool-tissue force profiles of 5 predetermined surgical tasks: 1) dissection, 2) coagulation, 3) retracting, 4) pulling, and 5) manipulating. Force profile for each trial included force duration, average, maximum, minimum, range, standard deviation (SD), and correlation coefficient. Force errors including unsuccessful trial bleeding or incomplete were compared between surgeons and with successful trials. RESULTS: Force data from 718 trials were collected. The mean (standard deviation) of force used in all surgical tasks and across all surgical levels was 0.20 ± 0.17 N. The forces exerted by trainee surgeons were significantly lower than those of the mentor (0.15 vs. 0.24; P < 0.0001). A total of 18 (4.5%) trials were unsuccessful, 4 of them being unsuccessful trial-bleeding and the rest, unsuccessful trial-incomplete. The force in unsuccessful trial-bleeding was higher than successful trials (0.3 [0.09] vs. 0.17 [0.11]; P = 0.0401). Toward the end of surgery, higher force was observed (0.17 vs. 0.20; P < 0.0001). CONCLUSIONS: The quantification of tool-tissue forces during hemangioblastoma surgery with feedback to the surgeon, could well enhance surgical training and allow avoidance of bleeding associated with high force error.

Endoscopic Transnasal Resection of Midline Skull Base Meningiomas: Tumor Consistency and Surgical Outcomes.

Background The endoscopic transnasal approach (ETA) has proven to be of great value in the resection of midline skull base meningiomas when compared with traditional approaches. Our objective was to assess tumor consistency in relation to surgical outcomes for midline meningiomas (MMs) resected using ETA. Methods Radiological preoperative features, including the tumor to cerebellar peduncle T2-weighted magnetic resonance imaging (MRI) ratio (TCTI), were evaluated. The intraoperative consistency assessment was performed by the surgeon, which determined if the tumor was soft (resectable by suction) or firm (required a cavitation ultrasonic aspirator). Surgical resection and postoperative complications were evaluated in relation to tumor consistency. Results Twenty patients were evaluated; 6 were classified as firm and 14 were classified as soft. The mean TCTI ratio was 1.7 and the median was 1.7 (range: 1.3-2.4). Three firm tumors had a ratio of <1.6. All soft tumors had a ratio of ≥1.6 with three outliers. Additionally, 66.7% of patients with firm tumors had complications compared with 35.7% of patients with soft tumors. Only 33.3% of firm tumors underwent gross total resection (GTR) in comparison to 79.0% of tumors with a soft consistency. Conclusion In our analysis, we found that tumor consistency was significantly related to short-term surgical outcomes in MMs resected using the ETA. The TCTI ratio was found to be the most reliable predictor with a sensitivity of 76.9% and a specificity of 40.0%. Our findings suggest that traditional cranial approaches should be considered as the first surgical option for managing firm MMs.

Comparing the Ability of Various Resin-Based Composites and Techniques to Seal Margins in Class-II Cavities.

Background: Resin-based composites (RBCs) provide excellent esthetics but the marginal micro-leakage in the proximal cavities remains a major concern. The aim of the present study was to assess the ability of various dental RBCs and techniques utilized for sealing deep dentin margin in class-II cavities. Methods: Box-cavities (class-II) on the distal and mesial surfaces of extracted (premolar) teeth were prepared with a gingival margin placed 1mm apical to the cemento-enamel junction. Teeth with prepared class II cavities were randomly divided into four study groups according to the type of restorative materials (conventional RBC; bulk-fill RBC; conventional RBC lined with flowable RBC and conventional RBC lined with resin-modified glass-ionomer-cement (GIC) as open sandwich-technique). Each group was further subdivided into a total-etch subgroup in which a separate etching step was performed before applying the bonding agent and a self-etch subgroup in which a self-etch adhesive system was used (n = 10). For each group, cavities were restored using the respective restorative materials and techniques, subjected to 1000 thermocycles, and placed in the methylene-blue dye. The specimen teeth were sectioned for further microscopic examination for micro-leakage. Results: The least dye penetration values were reported for group 4 (GIC) followed by the group Bulk-fill using the self-etch adhesive system (group 2b). The highest dye penetration was reported for the group Bulk-fill using the total-etch adhesive system (2a), followed by the group conventional RBC using the total-etch adhesive system). The total-etch adhesive system had significantly greater micro-leakage compared to the self-etch adhesive system (1a) (p = 0.026). Conclusions: The self-etch adhesive system significantly reduced the micro-leakage compared to the total-etch system. Bulk-fill RBC when bonded with the self-etch adhesive provided good marginal sealing ability comparable to open sandwich-technique using GIC.

Effects of compressive lesions on intraoperative human spinal cord elasticity.

OBJECTIVE: Although evaluating tissue elasticity has various clinical applications, spinal cord elasticity (SCE) in humans has never been well documented. In this study, the authors aimed to evaluate the impact of compression on human SCE in vivo. METHODS: The authors prospectively assessed SCE using intraoperative shear wave elastography (SWE). All consecutive patients undergoing spinal cord (SC) decompression (laminectomy or corpectomy) between June 2018 and June 2019 were included. After intraoperative exposure of the patient's dura mater, at least three SWE measurements of the SC and its coverings were performed. Intraoperative neurological monitoring in the form of motor and somatosensory evoked potentials was utilized. Cases were divided into two groups based on the state of SC compression following bone removal (laminectomy or corpectomy): patients with adequate decompression (the decompressed SC group [DCG]) following bone removal and patients with remining compression, e.g., compressing tumor or instability (the compressed SC group [COG]). RESULTS: A total of 25 patients were included (8 females and 17 males) with a mean age of 48.28 ± 21.47 years. Most cases were degenerative diseases (10 cases) followed by tumors (6 cases), and the compression was observed at cervical (n = 14), thoracic (n = 9), and conus medullaris (n = 2) levels. The COG (6 cases) expressed significantly higher elasticity values, i.e., greater stiffness (median 93.84, IQR 75.27-121.75 kPa) than the decompressed SC in DCG (median 9.35, IQR 6.95-11.22 kPa, p < 0.001). Similarly, the compressed dura mater in the COG was significantly stiffer (mean ± SD 121.83 ± 70.63 kPa) than that in the DCG (29.78 ± 18.31 kPa, p = 0.042). Following SC decompression in COG, SCE values were significantly reduced (p = 0.006; adjusted for multiple comparisons). Intraoperative monitoring demonstrated no worsening from the baseline. CONCLUSIONS: The current study is to the authors' knowledge the first to quantitatively demonstrate increased stiffness (i.e., elasticity value) of the human SC and dura mater in response to external compression in vivo. It appears that SCE is a dynamic phenomenon and is reduced following decompression. Moreover, the evaluation of human SCE using the SWE technique is feasible and safe. Information from future studies aiming to further define SCE could be valuable in the early and accurate diagnosis of the compressed SC.

Shear wave elastography for intracranial epidermoid tumors.

BACKGROUND: Ultrasound elastography (USE) is a novel technique that assesses the mechanical properties of body tissues in real time. Based on elasticity measurements, USE enables the differentiation of tumor tissue from surrounding normal tissue. OBJECTIVES: We aimed to evaluate an intraoperative SWE technique for differentiating tumor tissue (epidermoid cyst) from the surrounding normal brain tissue based on elastic properties. METHODS: We prospectively report the intraoperative elasticity assessments of four patients diagnosed with epidermoid cysts. Along with standard ultrasonography, intraoperative shear wave elastography (SWE) was used to identify tumor tissue and assess the elasticity of each tumor and the surrounding normal brain. RESULTS: USE enabled the differentiation between epidermoid cysts and the surrounding normal brain tissue in real time intraoperatively; visual data (SWE elasticity map) and quantitative data (elasticity measurements in kilopascals) were utilized to identify the epidermoid cyst based on its elastic properties. The area representing the epidermoid cyst had an increased elasticity on SWE view and high mean elasticity values (193.7 ± 70.9 kPa in case 1, 168 ± 24.5 kPa in case 2, 205.1 ± 6.7 kPa in case 3, and 101.3 ± 12.6 kPa in case 4). The area representing the adjacent normal brain tissue on SWE view had lower mean elasticity values (14.9 ± 1.9 kPa in case 1, 22.6 ± 8.3 kPa in case 2, and 23.8 ± 1.4 kPa in case 4). CONCLUSION: This study demonstrates the feasibility and promising value of SWE as an intraoperative tool during epidermoid cyst resection. Epidermoid tissue remnants that are hidden from the microscopic view can be detected using SWE.

Interhemispheric arachnoid cyst.

BACKGROUND: Interhemispheric arachnoid cysts are uncommon and typically associated with other midline neurodevelopmental disorders, such as complete or partial agenesis of the corpus callosum. CASE DESCRIPTION: We report a case of a 27-year-old woman with worsening headache, memory deficit, and radiological progression of an interhemispheric arachnoid cyst. The treatment consisted of craniotomy for interhemispheric cyst fenestration into both the interhemispheric cistern and lateral ventricle. The postoperative course was unremarkable, with considerable clinical improvement and significant reduction in cyst size. CONCLUSION: We successfully treat a patient with an enlarging arachnoid cyst and associated progressive symptoms with microsurgical fenestration.

Expanded transnasal approaches to the skull base in the Middle East: Where do we stand?

BACKGROUND: Endoscopic transnasal surgery has gained rapid global acceptance over the last two decades. The growing literature and understanding of anterior skull base endoscopic anatomy, in addition to new dedicated endoscopic instruments and tools, have helped to expand the use of the transnasal route in skull base surgery. OBJECTIVE: Report our early experience in expanded endoscopic transnasal surgery (EETS) and approach to skull base neoplasms. DESIGN: Descriptive, retrospective case series. SETTING: Major tertiary care center. PATIENTS AND METHODS: A retrospective case review was conducted at King Saud University Medical City between December 2014 and August 2019. Cases with skull base neoplasms that underwent EETS were included. EETS was defined as endoscopic surgical exposure that extended beyond the sellar margins (prechiasmatic sulcus superiorly, clival recess inferiorly, cavernous carotid lines laterally). Routine transsphenoidal pituitary neoplasms, neoplasms of sinonasal origin and meningoencephaloceles were excluded. MAIN OUTCOME MEASURES: Preoperative clinical assessment, imaging results, surgical approach, and hospital course were all retrieved from the patient electronic charts. Clinical follow-up, perioperative complications, and gross residual tumor rates were documented and reviewed. SAMPLE SIZE AND CHARACTERISTICS: 45 cases of EETS, 13 males and 32 females with mean age of 39.0 (17.7) years (range 2-70 years). RESULTS: The series comprised a wide range of pathologies, including giant pituitary adenoma (8 cases), meningioma (23 cases), craniopharyngioma (4 cases), chordoma (4 cases), optic pathway glioma (2 cases), epidermoid neoplasms (2 cases), astrocytoma (1 case), and teratoma (1 case). For the entire series, gross total resection was achieved in 25/45 operations (55.5%). Postoperative cerebrospinal fluid leak was the most common complication observed in 9 patients (20%) which were all managed endoscopically. Major vascular complications occurred in 2 patients (4.4%) and are described. Other complications are outlined as well. No mortality was observed. CONCLUSIONS: EETS to the skull base can be done with results comparable to traditional approaches. More work is needed to expand our experience, improve outcomes, and educate the public and medical community in our region about the usefulness of this approach. LIMITATIONS: Sample size and study design. CONFLICT OF INTEREST: None.

Aggressive surgical management of recurrent intracranial juvenile xanthogranuloma: case report and review of the literature.

INTRODUCTION: Juvenile xanthogranuloma (JXG) with the central nervous system (CNS) involvement is a rare disease entity that remains poorly understood, especially when the condition develops following treatment for Langerhans cell histiocytosis (LCH). CASE REPORT: A 21-year-old man who was diagnosed with LCH at age 2, several years following which he developed signs and symptoms of CNS involvement. Magnetic resonance imaging (MRI) of the brain revealed JXG with bilateral choroid plexus involvement. As radiation therapy for the intraventricular masses proved unsuccessful, he underwent two surgical resections. In the following years, he developed another large JXG in the meninges, which was managed conservatively until he required surgery due to symptom progression. Twelve years after the first surgery, the patient is in stable condition with no evidence of recurrence. CONCLUSION: Due to the rarity of JXG in the CNS, optimal treatment strategies and the precise duration of therapy remain to be determined. Future studies should aim to develop an appropriate treatment algorithm for such rare cases.

Pediatric intracranial hypertension. Experience from 2 Tertiary Centers.

OBJECTIVE: To review the experience of 2 tertiary centers in Saudi Arabia with intracranial hypertension (IH) in the pediatric population. METHODS: We retrospectively reviewed and analyzed pediatric patients diagnosed with IH from June 2002 to May 2017 in 2 institutes. RESULTS: We identified 53 patients (30 females and 23 males) with a mean age of 7 years at the time of presentation. Among them, 41 patients were younger than 12 years, and 12 were older. Obese and overweight patients constituted 27.00% (n = 14) of all cases, 8 (66.7%) of whom were older than 12 years. The most common presenting feature was papilledema followed by headache. Vitamin D deficiency, which constituted the most common associated condition, was identified in 12 (22.6%) patients. Acetazolamide was the treatment option in 98.11% of patients, and only 5.7% underwent surgical interventions. The length of follow-up ranged from 6 months to 8 years. CONCLUSION: Intracranial hypertension is rare in children and commonly seen in overweight females older than 12 years similar to adults. Patients younger than 12 years tend to develop secondary IH. More studies are needed to characterize the clinical presentation and guide the management plan.

Endoscopic Transnasal Resection of Suprasellar Teratoma.

BACKGROUND: Intracranial teratomas are rare tumors that usually present during the second decade of life. Among intracranial teratomas, suprasellar germ cell tumors in particular are extremely rare. We present the case of an 18-year-old girl who underwent a successful endoscopic transnasal resection of a suprasellar teratoma with a mixed germ cell component. CASE DESCRIPTION: An 18-year-old girl presented with progressive visual disturbance, headache, weight loss, and fatigue for 2 weeks. She had decreased vision in her right eye and double vision when looking to the right side. On examination, she had right-side complete abducens nerve palsy and partial oculomotor nerve palsy bilaterally. Brain imaging revealed a large suprasellar lesion consistent with a germ cell tumor. The patient underwent a transnasal endoscopic resection of the lesion. Pathology showed a mixed germ cell tumor (80% mature cystic teratoma, 18% yolk sac tumor, and 2% germinoma). The mature teratomatous elements identified included skin with sebaceous material, hair, cartilage, acini, colonic mucosa, muscle, nerve bundles, and adipose tissue. Postoperative magnetic resonance imaging (MRI) showed residual tumor in the left cavernous sinus and anterior clinoid process superiorly. At a 1-year follow-up, the double vision had resolved, and her vision showed progressive improvement. The patient was maintained on treatment for diabetes insipidus, hypothyroidism, and adrenal insufficiency. Her last MRI showed no signs of tumor progression. CONCLUSIONS: The present case demonstrates a safe endoscopic transnasal surgical resection of a rare suprasellar tumor, mixed teratoma, with intra-axial extension. The endoscopic transnasal approach can be considered a valid option for a suprasellar lesion.

Tumor-associated macrophage infiltration in meningioma.

BACKGROUND: Meningioma, a most common brain tumor, has a high rate of recurrence. Tumor-associated macrophages (TAMs) are the most abundant immune cell type in meningioma. TAMs display functional phenotypic diversity and may establish either an inflammatory and anti-tumoral or an immunosuppressive and pro-tumoral microenvironment. TAM subtypes present in meningioma and potential contribution to growth and recurrence is unknown. METHODS: Immunofluorescence staining was used to quantify M1 and M2 TAM populations in tissues obtained from 30 meningioma patients. Associations between M1 and M2 cells, M1:M2 cell ratio to tumor characteristics, WHO grade, recurrence, size, location, peri-tumoral edema, and patient demographics such as age and sex were examined. RESULTS: TAM cells accounted for ~18% of all cells in meningioma tissues. More than 80% of infiltrating TAMs were found to be of pro-tumoral M2 phenotype and correlated to tumor size (P = .0409). M1:M2 cell ratio was significantly decreased in WHO grade II, compared to grade I tumors (P = .009). Furthermore, a 2.3-fold difference in M1:M2 ratio between primary (0.14) and recurrent (0.06) tumors was observed (n = 18 and 12 respectively, P = .044). CONCLUSION: This study is the first to confirm existence of pro-tumoral M2 TAMs in the meningioma microenvironment, emphasizing its potential role in tumor growth and recurrence.

Endoscopic transnasal resection of optic pathway pilocytic astrocytoma.

PURPOSE: Optic pathway gliomas (OPGs) are low-grade neoplasms that primarily affect children. The management of OPGs remains controversial. Reports on the use of the endoscopic endonasal approach (EEA) in OPGs are extremely limited, and no such reports exist on its utility for pediatric OPGs. Here, we report our results and experience with OPGs treated with the EEA. METHODS: We retrospectively reviewed the medical records of OPG patients who were treated surgically via the EEA at our institutions from 2015 to 2017. Data on the demographics, clinical presentation, surgical complications, clinical outcomes, radiological imaging, and visual outcomes were recorded for each patient. RESULTS: Four cases were identified, with visual disturbances being the predominant complaint. The mean patient age was 15.5 years. Three cases showed normal preoperative hormonal profiles, but one patient had hypothyroidism. All tumors identified in this study were World Health Organization grade I pilocytic astrocytomas. Surgical complications included hypopituitarism in two patients, meningitis in two patients, cerebrospinal fluid leak in one patient, and transient diabetes insipidus in one patient. No patient experienced worsening neurological or visual symptoms postoperatively. CONCLUSIONS: Although our data are preliminary, the EEA provides a direct corridor to OPG with acceptable results in terms of tumor resection and visual outcomes. Hypothalamic-pituitary axis dysfunction remains a limitation of any treatment modality for OPGs and should be considered whenever possible. Definitive conclusions are pending as the learning curve of this approach is steep. Further work is needed to understand patient selection for such an approach.

In vivo assessment of spinal cord elasticity using shear wave ultrasound in dogs.

OBJECTIVE: Evaluation of living tissue elasticity has wide applications in disease characterization and prognosis prediction. Few previous ex vivo attempts have been made to characterize spinal cord elasticity (SCE). Recently, tissue elasticity assessment has been clinically feasible using ultrasound shear wave elastography (SWE). The current study aims to characterize SCE in healthy dogs, in vivo, utilizing SWE, and to address SCE changes during compression. METHODS: Ten Greyhound dogs (mean age 14 months; mean weight 14.3 kg) were anesthetized and tracheally intubated, with hemodynamic and neurological monitoring. A 3-level, midcervical laminectomy was performed. SCE was assessed at baseline. Next, 8- and 13-mm balloon compressions were sequentially applied ventral to the spinal cord. RESULTS: The mean SCE was 18.5 ± 7 kPa. Elasticity of the central canal, pia mater, and dura mater were 21.7 ± 9.6 kPa, 26.1 ± 14.8 kPa, and 63.2 ± 11.5 kPa, respectively. As expected, the spinal cord demonstrated less elasticity than the dura mater (p < 0.0001) and pia mater (trend toward significance p = 0.08). Notably, the 13-mm balloon compression resulted in a stiffer spinal cord than at baseline (233 ± 73 kPa versus 18.5 ± 7 kPa, p < 0.0001) and 8-mm balloon compression (233 ± 73 kPa versus 185 ± 68 kPa, p < 0.048). CONCLUSIONS: In vivo SCE evaluation using SWE is feasible and comparable to earlier reports, as demonstrated by physical sectioning of the spinal cord. The compressed spinal cord is stiffer than a free spinal cord, with a linear increase in SCE with increasing mechanical compression. Knowledge of the biomechanical properties of the spinal cord including SCE has potential implications for disease management and prognosis.

Adrenal Axis Insufficiency After Endoscopic Transsphenoidal Resection of Pituitary Adenomas.

INTRODUCTION: Hormonal insufficiency of 1 or more pituitary axes can appear after pituitary surgery. Adrenal axis impairment after surgery can lead to serious consequences if not identified and treated. OBJECTIVE: Assess early and late postoperative adrenal insufficiency (AI) and identify the risk factors predicting their occurrence after endoscopic transsphenoidal resection of pituitary adenomas. METHOD: Retrospective review identified 176 pituitary adenomas resected using an endoscopic transsphenoidal approach. Patients taking steroids preoperatively, Cushing disease patients, and patients with incomplete records were excluded. Sixty-nine patients were excluded according to our exclusion criteria. RESULTS: The study group thus included 107 patients (total of 111 operations). The median age was 50 years (range, 18-89 years). The median duration of follow-up was 30 months (range, 6-74 months). Eighty-three patients (74.7%) had macroadenomas, and 89 (59.3%) had nonfunctional adenomas. Of the 111 procedures, 61 patients (55%) had early AI. Of the 61 patients, 48 patients (79%) were not taking steroids in long-term follow-up, and only 13 (21%) required long-term replacement. Sixteen of the patients undergoing 111 procedures (14.4%) had AI on long-term follow-up. Of those 16 patients, 13 were already taking steroids and 3 had new diagnoses of AI. Age, male gender, and cerebrospinal fluid (CSF) leaks were associated with persistent postoperative AI (P = 0.018, P = 0.001, P = 0.007, respectively). CONCLUSION: Hypothalamic pituitary adrenal axis insufficiency is common after endoscopic transsphenoidal surgery. Male gender, age greater than 50 years, visual impairment, and intraoperative CSF leak were correlated with late postoperative AI. More than two thirds of patients in whom early AI developed did not require steroids in the long term.

Central Nervous System Lymphoma in a Patient with Chronic Lymphocytic Leukemia: A Case Report and Literature Review.

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia that affects older adults in the Western world. Symptomatic nervous system invasion in undiagnosed CLL is rare, poorly understood, challenging to treat, and associated with decreased survival. The average survival of CLL patients with central nervous system (CNS) involvement is 3.79 years as compared to six years in CLL patients without CNS involvement. Autopsy studies demonstrated a high incidence of undiagnosed CLL with CNS involvement, suggesting that CNS involvement is either underdiagnosed or subclinical. Although the most common site of CNS involvement is the leptomeninges, our case demonstrates an extremely rare form of CNS diffuse large B-cell parenchymal involvement in a patient with a concurrent diagnosis of systemic CLL.