Performing Awake Surgeries in Times of COVID-19 - A Singapore Experience.

INTRODUCTION: It has been 17 years since the severe acute respiratory syndrome outbreak and Singapore is facing yet another daunting pandemic - the novel coronavirus (COVID-19). To date, there are 57,607 cases and 27 casualties. This deadly pandemic requires significant changes especially in the field of awake surgeries for intra-axial tumors that routinely involve long clinic consults, significant interactions between patient and multiple other team members pre, intra, and postoperatively. MATERIALS AND METHODS: A retrospective review of all awake cases done during the COVID-19 pandemic from February to June 2020 was done. In this article, we outline the rigorous measures adopted during the COVID-19 pandemic that has allowed us to proceed with awake surgeries and intraoperative mapping at our institution. RESULTS AND DISCUSSION: We have divided the protocol into various phases of care of patients planned for an awake craniotomy. Preoperatively, teleconsults have been used where possible thereby limiting multiple hospital visits and interaction. Intraoperatively, safety nets have been established during asleep-awake-asleep phases of awake craniotomy for all the team members. Postoperatively, early discharge and teleconsult are being employed for rehabilitation and follow-ups. CONCLUSIONS: Multiple studies have shown that with intraoperative mapping, we can improve neurological outcomes. As the future of the pandemic remains unknown, the authors believe that surgical treatment should not be delayed for intracranial tumors. Awake craniotomies and intraoperative mapping can be safely carried out by adopting the described protocols with combination of multiple checkpoints and usage of telecommunication.

Freehand Insertion of External Ventricular Drainage Catheter: Evaluation of Accuracy in a Single Center.

INTRODUCTION: External ventricular drain (EVD) placement is the gold standard for managing acute hydrocephalus. Freehand EVD, using surface anatomical landmarks, is performed for ventricular cannulation due to its simplicity and efficiency. This study evaluates accuracy and reason(s) for misplacements as few studies have analyzed the accuracy of freehand EVD insertion. PATIENTS AND METHODS: Preoperative and postoperative computed tomography scans of patients who underwent EVD insertion in 2014 were retrospectively reviewed. Diagnosis, Evans ratio, midline shift, position of burr hole, length of the catheter, and procedural complications were tabulated. The procedures were classified as satisfactory (catheter tip in the frontal horn ipsilateral lateral ventricle) and unsatisfactory. Unsatisfactory cases were further analyzed in relation to position of burr hole from midline and length of the catheter. RESULTS: Seventy-seven EVD placements in seventy patients were evaluated. The mean age of the patients was 57.5 years. About 83.1% were satisfactory placements and 11.7% were unsatisfactory in the contralateral ventricle, corpus callosum, and interhemispheric fissure. Nearly 5.2% were in extraventricular locations. Almost 2.6% EVD placements were complicated by hemorrhage and 1 catheter was reinserted. Suboptimal placements were significantly associated with longer intracranial catheter length. The mean length was 66.54 ± 10.1 mm in unsatisfactory placements compared to 58.32 ± 4.85 mm in satisfactory placements. Between the two groups, no significant difference was observed in Evans ratio, midline shift, surgeon's experience, distance of burr hole from midline, and coronal suture. CONCLUSION: Freehand EVD insertion is safe and accurate. In small number of cases, unsatisfactory placement is related to longer catheter length.

Dissecting distal cerebellar artery aneurysms: options beyond a parent vessel sacrifice.

Parent vessel occlusion (PVO) is the conventional endovascular treatment (EVT) for dissecting distal cerebellar artery aneurysms (DCAA). The associated ischemic sequelae are often well-tolerated. However, at the outset, the magnitude of this risk is uncertain. Meanwhile, non-PVO endovascular treatments (EVT) are deemed to provide incomplete protection from a rebleed. This study reviews our experience in the management of dissecting DCAA with emphasis on the effectiveness of parent vessel-preserving endovascular strategies as compared to PVO. Our institutional database was reviewed for all the dissecting DCAA aneurysms treated by endovascular means between Nov 2015 and Oct 2018. Their clinical presentations, imaging findings, EVT techniques, and clinical outcomes were retrospectively evaluated. Eighteen dissecting DCAA were identified: 13 in the posterior-inferior cerebellar artery (PICA), 3 in anterior-inferior cerebellar artery (AICA), and 2 in superior cerebellar artery (SCA). Median patient age was 61 years (range 40-86; average 60.7 years) with a 5:1 female predominance. Nine (6 in the PICA and 3 in the AICA) patients were managed by parent vessel-preserving strategies (6 with isolated endosaccular coiling and 3 with telescoping stents) while the remaining 9 (7 in the PICA and 2 in the SCA) were treated by PVO.The frequency of early rebleed was the same (11%) in both the treatment arms. One patient from the PVO arm suffered an extensive cerebellar infarct that mandated decompressive craniectomy and adversely affected her recovery. There were no such complications in patients treated with parent vessel-preserving strategies. No recurrence/rebleed was encountered in the 3 aneurysms secured using telescoping stents. Overall, excellent clinical outcomes (mRS of 0 and 1) were sparsely seen in the patients who had PVO (89 vs 23%). In dissecting DCAA, aforedescribed, parent vessel-preserving strategies are as effective as the more frequently used option of PVO in preventing an early rebleed. However, these are technically challenging, may be feasible in a smaller proportion of patients, and would need meticulous imaging follow-up in the acute period. When successfully implemented, these strategies can deliver excellent clinical outcomes and eliminate the uncertain risk of ischemic complications associated with PVO.

Two Extraordinary Sellar Neuronal Tumors: Literature Review and Comparison of Clinicopathologic Features.

Objectives: The list of tumors involving the pituitary gland has been expanded to include a variety of neuronal and paraneuronal tumors in the 2017 World Health Organization tumor classification of endocrine organs. All the entities included in this category are distinctly rare, with limited case reports in the literature. Methods: We illustrate two extraordinary sellar tumors with neuronal differentiation: a sellar paraganglioma and a sellar neurocytoma, with thorough literature review and comparison of the clinicopathologic features of these entities. Results: Both entities are exceptionally rare and tend to be misdiagnosed as pituitary adenoma preoperatively. Both entities demonstrate frequent clinical recurrence compared with pituitary adenoma, as well as the rare occurrence of metastatic disease. Conclusions: In evaluating a sellar tumor with an uncommon morphology and neuroendocrine differentiation, an increased awareness of the unusual entities that may involve the sellar region and a judicious panel of immunohistochemical studies should improve the diagnosis.

Long-term outcome in extracranial-intracranial bypass surgery for severe steno-occlusive disease of intracranial internal carotid or middle cerebral artery.

OBJECTIVES: We report the long-term outcome and rates of recurrent cerebral ischemic events in our cohort of carefully selected patients after STA-MCA bypass for severe steno-occlusive disease of intracranial ICA or MCA with exhausted cerebral vasodilatory reserve. PATIENTS AND METHODS: In this retrospective study, we reviewed the hospital records for all patients who underwent direct superficial temporal artery-middle cerebral artery bypass surgery at our institution from January 2010 to August 2017. Patients were included in the study if they presented with transient ischemic attack or non-disabling stroke due to a severe steno-occlusive lesions of the intracranial internal carotid artery or middle cerebral artery with abnormal cerebral vasodilatory reserve on imaging. The overall event rate is defined as transient ischemic attack, acute ischemic stroke, peri-operative stroke or death. RESULTS: 69 patients were included in the study. The median age of cohort was 57 years (inter-quartile range 36-78). Median follow up period in our study was 73 months (range 2-90 months). The overall event rate post-treatment during the follow up period is 20.2%. In contrast, previous studies have showed that patients who underwent best medical therapy had a higher recurrent ischemic stroke rate over a 2-3-year period. CONCLUSION: This study suggests that carefully selected patients with severe steno-occlusive disease and significantly abnormal cerebral hemodynamic reserve who undergo extracranial-intracranial bypass surgery, may benefit from long-term prevention of symptomatic cerebral ischemic events.

Early Decompressive Hemicraniectomy for Malignant Middle Cerebral Artery Infarction in Asian Patients: A Single-Center Study.

INTRODUCTION: Early decompression craniectomy (within 48 hours of stroke onset) in acute and malignant middle cerebral artery (MCA) ischemic stroke (IS) reduces mortality and increases the proportion of patients with favorable functional outcome. Various cultural and social issues among Asians lead to some differences in clinical practice, especially when surgical interventions are involved. Accordingly, decompressive craniectomy in Asian patients with stroke is often delayed. MATERIALS AND METHODS: Data for all patients with acute IS hospitalized in our center were entered into a prospectively maintained registry. In this retrospective analysis, data for all patients with malignant MCA IS who underwent decompressive craniectomy were extracted. Various demographic, clinical, and neuroimaging factors were analyzed for identifying independent predictors of favorable functional outcome at 6 months, which was defined as modified Rankin Scale score of 0-3 points. RESULTS: From January 2005 to December 2014, a total of 75 patients with acute MCA IS underwent decompressive craniectomy. Median age was 55 years (interquartile range 44-64) with male preponderance (66%) and median National Institute of Health Stroke Scale score 21 points (interquartile range 18-24). A considerable proportion of these patients (38.7%) received intravenous thrombolysis. The majority (70%) of patients suffered right MCA IS, and decompressive surgery was performed within 48 hours of symptom onset in 50 (67%) of the patients. Favorable functional outcome was achieved in 25 (33.3%) patients at 6 months. Right MCA stroke (odds ratio 9.158; 95% confidence interval 1.881-44.596, P = 0.006) and early decompression surgery (odds ratio 4.011; 95% confidence interval 1.058-15.208, P = 0.041) were independent predictors of favorable functional outcome at 6 months. CONCLUSIONS: Early decompression craniectomy, especially in right MCA ischemic stroke, is associated with better favorable functional outcome.

Body mass index and the risk of postoperative cerebrospinal fluid leak following transsphenoidal surgery in an Asian population

<p><b>INTRODUCTION</b>Postoperative cerebrospinal fluid (CSF) leak is a serious complication following transsphenoidal surgery for which elevated body mass index (BMI) has been implicated as a risk factor, albeit only in two recent North American studies. Given the paucity of evidence, we sought to determine if this association holds true in an Asian population, where the BMI criteria for obesity differ from the international standard.</p><p><b>METHODS</b>A retrospective study of 119 patients who underwent 123 transsphenoidal procedures for sellar lesions between May 2000 and May 2012 was conducted. Univariate and multivariate logistic regression analyses were performed to investigate the impact of elevated BMI and other risk factors on postoperative CSF leak.</p><p><b>RESULTS</b>10 (8.1%) procedures in ten patients were complicated by postoperative CSF leak. The median BMI of patients with postoperative leak following transsphenoidal procedures was significantly higher than that of patients without postoperative CSF leak (27.0 kg/m vs. 24.6 kg/m; p = 0.018). Patients categorised as either moderate or high risk under the Asian BMI classification were more likely to suffer from a postoperative leak (p = 0.030). Repeat procedures were also found to be significantly associated with postoperative CSF leak (p = 0.041).</p><p><b>CONCLUSION</b>Elevated BMI is predictive of postoperative CSF leak following transsphenoidal procedures, even in an Asian population, where the definition of obesity differs from international standards. Thus, BMI should be considered in the clinical decision-making process prior to such procedures.</p>

Percutaneous pedicle screw fixation for thoracolumbar burst fracture: a Singapore experience

<p><b>INTRODUCTION</b>This study aimed to evaluate the clinical and radiological outcomes, and safety and efficacy of percutaneous pedicle screw fixation (PPSF) in the treatment of thoracolumbar burst fractures.</p><p><b>METHODS</b>This was a retrospective review of patients with thoracolumbar burst fractures treated with PPSF in a single hospital from 2010 to 2011. Baseline data included patient demographics, mechanism of injuries, fracture level, neurologic status and the number of percutaneous screws inserted. Kyphotic angle correction, vertebral body height restoration and mid-sagittal canal diameter improvement were used to assess radiological outcome. Screw misplacement, operative complications, functional improvement (ASIA score) and pain score on visual analogue scale were used to assess safety and clinical outcomes.</p><p><b>RESULTS</b>21 patients with 25 thoracolumbar burst fractures were treated with 134 percutaneous screws. There was significant improvement in kyphotic angle correction (mean difference 6.1 degrees, p = 0.006), restoration of anterior and posterior vertebral height (mean difference 19.7%, p < 0.01 and mean difference 6.6%, p = 0.007, respectively) and mid-sagittal canal diameter (mean difference 15.6%, p = 0.007) on discharge. These improvements remained statistically significant at six months post operation for restoration of anterior vertebral body height (mean difference 9.8%, p = 0.05) and mid-sagittal diameter (mean difference 30.0%, p < 0.01).</p><p><b>CONCLUSION</b>In this first local review, we have shown that PPSF is a relatively safe and effective technique for treating selected thoracolumbar burst fractures, and that it yields satisfactory results. However, its long-term outcome and efficacy need to be further evaluated.</p>

External ventricular drain infections: successful implementation of strategies to reduce infection rate

<p><b>INTRODUCTION</b>External ventricular drain (EVD) infections can cause serious complications. We performed an audit of EVD infections within our neurosurgical unit. Through this study, we aimed to reduce the incidence of external ventricular drain-related infection, including ventriculities in neurosurgical patients.</p><p><b>METHODS</b>We conducted an audit of the EVD infections in our institution observed over a one-and-a-half year period. This was conducted in three phases. A baseline EVD infection rate was determined for Phase I, from January to June 2007. We introduced the following measures to reduce EVD infection rate in Phase II, from July to December 2007: (1) For Neurosurgery doctors: performing proper surgical techniques to minimise intra-operative infections; educating junior doctors on proper CSF sampling from the EVD; and minimising the number of days the EVD is maintained in situ; (2) For Neurosurgery nurse clinicians: developing Standard Operating Procedures on nursing management of EVDs; conducting EVD care workshops for nurses working in neurosurgical wards; and competency skill checks on the management of EVDs for nurses working in the neurosurgical wards. Silver-coated EVDs were introduced in Phase III of the study from January to June 2008.</p><p><b>RESULTS</b>The EVD infection rate decreased from a baseline of 6.1% to 3.8% in Phase II; a further reduction from 3.8% to 0% was achieved during Phase III.</p><p><b>CONCLUSION</b>Good teamwork among doctors and nurses is essential for reducing EVD infection rate. We managed to reduce EVD infections substantially and would continue to strive to remain infection-free in the future.</p>

Migration of the abdominal catheter of a ventriculoperitoneal shunt into the mouth: a rare presentation.

A 1-year-old boy with a history of exomphalos and hydrocephalus had surgeries to correct these pathologies. The ventriculopleural (VP(L)) shunt inserted for hydrocephalus was complicated by pleural effusion, for which a ventriculoperitoneal (VP) shunt was inserted on the contralateral side. He subsequently presented with protrusion of the distal VP shunt tip from the mouth due to perforation through the gastrointestinal tract. The child also had a history of peritonitis post-exomphalos repair, which may have predisposed him to this relatively uncommon shunt complication. Probable causes and risk factors of the perforation are discussed.