Faculty Bibliography

BACKGROUND:Neurovascular training models include animal models, synthetics, or computer simulation. In vivo models are expensive and require significant resources. Synthetic/computer models do not reflect the elasticity of fresh vessels. We describe an endovascular and microsurgical training model using a chicken thigh/leg. METHODS:20 chicken thigh/leg models were obtained. Angiography was utilized to understand the anatomy. Proximal cannulation with a 5-French catheter was achieved and connected to a hemostatic valve with a pump to simulate pulsatile flow. Aneurysms were created at the thigh-leg junction. For clipping training, 3 types of aneurysms were created to reproduce anatomy seen in middle cerebral, anterior communicating and posterior communicating aneurysms. RESULTS:The average cost per specimen from was $1.70 ± 0.30. The diameter of the proximal femoral artery (PFA) was 2.4 mm ± 0.2 mm. The length from the PFA to the aneurysm was 9.5 cm ± 0.7 cm. Distal catheterization was successful in all cases (n=6). Successful deployment of coils and a stent was achieved under fluoroscopic guidance. Gross over-sizing of coils and other mistakes led to aneurysm rupture. Each examiner performed an exploration of the pulsatile aneurysm, application and reapplication of a variety of clips and then final inspection of branching vessels to confirm patency. CONCLUSIONS:The chicken thigh/leg model provides training opportunities in microsurgical suturing, endovascular techniques for aneurysm obliteration, and microsurgical reconstruction of aneurysms. It combines affordability, time efficiency and reproducibility. Further studies measuring improvement in technical aneurysm management and comparison to other training models are warranted.

Background: Large anterior skull base meningiomas with significant extension through the floor of the anterior fossa into the ethmoid and sphenoid sinuses pose a surgical dilemma. Radical resection of these tumors as well as the skull base and sinus component can be curative. This can be achieved through either a transcranial approach or a combined transcranial/endonasal approach depending on the involvement of the sinuses. However, in doing so, patients are at significant risk for postoperative cerebrospinal fluid leak as well as infection. Given these risks and the benign nature of these tumors, especially WHO grade I meningiomas, many surgeons will choose not to resect the portion going through the skull base. The residual tumor can then be observed or radiated if there are signs of growth.
Objective(s): We propose the use of a staged combined approach to maximize resection and minimize risk of CSF leak or infection. Case Presentation: We present the case of a 55-year-old male, BMI of 37, who presented with 3 weeks of left eye blurry vision, 2 years of anosmia, and personality changes. The patient was found to have a 7.3x5.9x4.6 cm anterior skull base meningioma with significant surrounding parenchymal edema in the bilateral frontal lobes as well as extension through the floor of the anterior skull base and into the ethmoid and sphenoid sinuses ([Fig. 1a], b). He was taken for a bifrontal craniotomy and resection of the intracranial component with planned amputation of the tumor at the skull base which was covered with a pericranial flap. He recovered well with return of his vision to normal. Pathology demonstrated a WHO grade II atypical meningioma. Follow-up imaging demonstrated persistent residual tumor within the ethmoid and sphenoid sinus ([Fig. 2]). We discussed an endoscopic endonasal resection of the residual tumor and anterior skull base in a delayed fashion once the pericranial graft healed versus radiation. The patient preferred to proceed with resection. He underwent an endoscopic endonasal resection of the residual tumor within the sinus and remaining anterior skull base. At the time of surgery the tumor was easily separated from the pericranial graft which was well healed. No CSF was observed but a nasoseptal flap was placed for protection. He was discharged on POD2. Postoperative imaging demonstrated gross total resection of the residual tumor ([Fig. 3]).
Conclusion(s): The use of a delayed combined transcranial and endoscopic endonasal approach for anterior skull base meningiomas with significant intracranial and sinus tumor component potentially maximizes surgical resection while reducing the risk of CSF leak and infection. (Figure Presented)

Background: Surgical resection of pituitary adenomas is associated with a 10 to 30% rate of temporary diabetes insipidus with ~50% resolving within 1 week and 80% resolving at 3 months.[1] Adrenal insufficiency occurs in ~ 5 % of patients and can result in an Addisonian crisis if left undiagnosed postoperatively.[1] [2] Many studies have been performed looking at readmission rates after pituitary surgery. A review of over 1,200 cases demonstrated a readmission rate of 8.5% with the most common cause being hyponatremia (29.5%).[3] To reduce the rate of readmission for hyponatremia, some groups have demonstrated the effective use of outpatient fluid restriction criteria during the first week post-op.[4] These guidelines are intended for the management of standard postoperative hormonal fluctuations which do not necessitate endocrine consultation during hospitalization.
Objective(s): Retrospectively evaluate patients undergoing endoscopic endonasal resection of pituitary adenomas to identify areas for quality improvement through the development of more standardized postoperative guidelines.
Method(s): A retrospective review of 75 patients who underwent endoscopic endonasal resection of pituitary adenomas at a single academic center from 2013 to 2018. We evaluated the average length of stay, number of laboratory studies performed, need for hormone supplementation long term and short term, rate of gross-total resection, rate of cerebrospinal fluid leak, rate of infection, and 30-day readmission rate ([Table 1]). From this, we have developed a change in guidelines aimed at reducing length of stay, redundant laboratory studies, and reduced rate of readmission.
Conclusion(s): Although our current outcomes for resection of pituitary adenoma are on par with published data, we have identified areas of possible quality improvement which have since been implemented

Introduction The Department of Neurosurgery has a readmission rate goal of less than 9.7 for the fiscal year 2018 and less than 9.2 for the fiscal year of 2019. Over the past four fiscal quarters there has been an increase in the department's readmission rate, always exceeding the institutional goal. Methods All readmissions in the institution's dashboard for Q3 and Q4 for 2018 and Q1 and Q2 of 2019 were reviewed by way of chart review. These were divided into spine vs cranial, planned vs unplanned readmission, reason for readmission and consistency vs inconsistency with the institution's dashboard. Results In Q3 2018 the dashboard reported a readmission rate of 10.86. The final calculated actual readmission rate was 9.32. In Q4 2018 the dashboard reported a readmission rate of 11.04. The final calculated actual readmission rate was 9.27. In Q1 2019 the dashboard reported a readmission rate of 10.76. The final calculated actual readmission rate was 8.02. In Q2 2019 the dashboard reported a readmission rate of 10.73. The final calculated actual readmission rate was 7.30. The most common reason for unplanned readmissions were CSF leaks. The most common reason for planned readmissions were shunt placements after lumbar drain trials. The dashboard was correct in predicting planned vs unplanned readmissions 45.5% of the time. Conclusions The coding on the backend of the institution's dashboard is missing many staged and planned readmissions and is only accurate in coding planned vs unplanned readmissions half of the time. This is resulting in falsely elevated readmission rates. Despite the initial uptrend in readmissions, the actual readmission rates of the department are down trending and always below the institutional goal. This likely translates to other departments within the hospital. There needs to be a more efficient way to improve the coding and accuracy of the institution dashboards

BACKGROUND: Up to 20% of meningiomas are aggressive tumors with high recurrence rates and poor prognosis. Biomarkers predicting the risk of an unfavorable clinical course are lacking although aberrations in NF2, increased copy number variations and a hypomethylated phenotype have been associated with more aggressive behavior. Mutational signatures (MS) are characteristic patterns of somatic mutations seen in cancer genomes associated with aging, exposure to certain mutagens, or defective DNA repair. We aimed to identify MS patterns in clinically aggressive meningiomas.
METHOD(S): We performed whole exome sequencing of 18 de novo meningiomas (locally invasive and recurrent WHO I, n=6; atypical WHO II, n=4; anaplastic WHO III, n=8). Median PFS was 18.9 months. Copy numbers and DNA methylation phenotype were assessed by DNA methylation array analysis. Mutational signatures were identified using published signature algorithms (COSMIC).
RESULT(S): MS1 and MS5 (aging) were found in 18 (100%) cases. MS associated with defective DNA MMR were highly prevalent: MS20 and MS26 were detected in 18 (100%) and MS6 in 2 (12%) cases. MS12 (unknown etiology) was present in 14 (82%) cases. Despite the association with defective DNA MMR, none (0%) of the MS6 cases harbored somatic mutations associated with DNA MMR while MS12 tumors were enriched for mutations in DNA MMR (43%), chromatin remodeling (36%) and other cancer-associated genes (7%). MS6 tumors had significantly lower indels compared to non-MS6 tumors (p=0.01). Tumors with mutations in chromatin remodeling genes had a significantly higher rate of single nucleotide variants (SNVs) compared to cases without such mutations (p=0.02).
CONCLUSION(S): MS associated with defective DNA MMR were highly prevalent in this set of aggressive meningiomas. However, despite the association with DNA MMR, MS6 meningiomas harbored no somatic mutations associated with DNA MMR while MS12 tumors were enriched for mutations in DNA MMR, chromatin remodeling and cancerassociated genes

OBJECTIVECerebral venous sinus thrombosis (CVST) is a known complication of surgeries near the major dural venous sinuses. While the majority of CVSTs are asymptomatic, severe sinus thromboses can have devastating consequences. The objective of this study was to prospectively evaluate the true incidence and risk factors associated with postoperative CVST and comment on management strategies.METHODSA prospective study of 74 patients who underwent a retrosigmoid, translabyrinthine, or suboccipital approach for posterior fossa tumors, or a supratentorial craniotomy for parasagittal/falcine tumors, was performed. All patients underwent pre- and postoperative imaging to evaluate sinus patency. Demographic, clinical, and operative data were collected. Statistical analysis was performed to identify incidence and risk factors.RESULTSTwenty-four (32.4%) of 74 patients had postoperative MR venograms confirming CVST, and all were asymptomatic. No risk factors, including age (p = 0.352), BMI (p = 0.454), sex (p = 0.955), surgical approach (p = 0.909), length of surgery (p = 0.785), fluid balance (p = 0.943), mannitol use (p = 0.136), tumor type (p = 0.46, p = 0.321), or extent of resection (p = 0.253), were statistically correlated with thrombosis. All patients were treated conservatively, with only 1 patient receiving intravenous fluids. There were no instances of venous infarctions, hemorrhages, or neurological deficits. The rate of CSF leakage was significantly higher in the thrombosis group than in the nonthrombosis group (p = 0.01).CONCLUSIONSThis prospective study shows that the radiographic incidence of postoperative CVST is higher than that previously reported in retrospective studies. In the absence of symptoms, these thromboses can be treated conservatively. While no risk factors were identified, there may be an association between postoperative CVST and CSF leak.

Background/UNASSIGNED:Numerous medical society guidelines recommend discontinuation of antibiotics at a maximum of 24 hours after noninstrumented spinal surgery, even when a drain is left in place. As a result of these recommendations, our institution's Neurosurgery Quality Improvement Committee decided to stop administering prolonged prophylactic systemic antibiotics (PPSAs) to patients with drains after noninstrumented spinal surgery. Methods/UNASSIGNED:We retrospectively reviewed data for patients who had noninstrumented spinal surgery performed by a neurosurgeon at our institution between December 2012 and July 2014 (PPSA period) and December 2014 and July 2016 (non-PPSA period) and had a drain left in place postoperatively. In the PPSA period, patients received antibiotics until drain removal. In the non-PPSA period, patients received antibiotics for a maximum of 24 hours. Results/UNASSIGNED:= .24). Conclusion/UNASSIGNED:After discontinuing PPSAs for patients with noninstrumented spinal procedures, as is recommended for quality improvement, we saw a nonsignificant increase in our rate of SSIs. Further monitoring of this population is warranted.

OBJECTIVE The objective of this study was to determine the effects of a quality improvement initiative in which daily antibiotics and daily sampling of cerebrospinal fluid (CSF) were discontinued for patients with lumbar drains. METHODS The frequency of surgical site infections (SSIs), antibiotic-related complications (development of Clostridium difficile infection [CDI] and growth of resistant bacteria), and cost for patients with lumbar drains were compared during 3 periods: 1) prolonged prophylactic systemic antibiotics (PPSA) until the time of drain removal and daily CSF sampling (September 2013-2014), 2) PPSA and CSF sampling once after placement then as needed (January 2015-2016), and 3) antibiotics only during placement of the lumbar drain and CSF sampling once after placement then as needed (April 2016-2017). RESULTS Thirty-nine patients were identified in period 1, 53 patients in period 2, and 39 patients in period 3. There was no change in the frequency of SSI after discontinuation of routine CSF testing or PPSA (0% in period 1, 2% in period 2, and 0% in period 3). In periods 1 and 2, 3 patients developed infections due to resistant organisms and 2 patients had CDI. In period 3, 1 patient had an infection due to a resistant organism. The median cost of CSF tests per patient was $100.68 (interquartile range [IQR] $100.68-$134.24) for patients in period 1 and $33.56 (IQR $33.56-$33.56) in periods 2 and 3 (p < 0.001). The median cost of antibiotics per patient was $26.32 (IQR $26.32-$30.65) in periods 1 and 2 and $3.29 ($3.29-$3.29) in period 3 (p < 0.001). The cost associated with growth of resistant bacteria and CDI was $91,291 in periods 1 and 2 and $25,573 in period 3. CONCLUSIONS After discontinuing daily antibiotics and daily CSF sampling for patients with lumbar drains, the frequency of SSI was unchanged and the frequency of antibiotic-related complications decreased.