Trigeminal Somatosensory Evoked Potentials During Neurosurgical Procedures Using Electrical Stimulation of the Lips Under General Anesthesia.

Background Intraoperative neurophysiology monitoring is rapidly evolving with the advent of newer modalities. Long latency sensory evoked potentials from the trigeminal nerve distribution have rarely been demonstrated during neurosurgical procedures. Trigeminal sensory evoked potential (TSEP) can be used to prevent nerve injury during surgical procedures, such as those for trigeminal neuralgia and tumors involving the trigeminal nerve and pathway. Methodology We attempted to record TSEP from 12 subjects who underwent various neurosurgical procedures with low doses of inhalational anesthetic agents. We stimulated the upper and lower lip and recorded from C6 and Fz locations. We used 14-17 mA current stimuli with a pulse width of 50-150 microseconds and a stimulation rate of 2.1 Hz. Results We could obtain a clear, reproducible TSEP response in two out of 12 subjects. We observed a TSEP waveform with negative peaks at 13 and 27 milliseconds and a positive wave at around 19 milliseconds. Conclusions The TSEP produced by the electrical stimulation of the upper and lower lip can be detected from the scalp C5, C6, and Fz area even during neurosurgical procedures, even if inhalational anesthesia was used at induction, but only in a small proportion of cases. It appeared to reflect the activity of trigeminal cortical response. Avoiding the notch filter and turning off the inhalational agents are essential for a good response.

An Analysis of Eosinophil- and Basophil-Based Indices in Patients with Glioblastoma and their Correlation with Survival.

BACKGROUND: Glioblastoma (GBM) is the most frequently diagnosed malignant brain tumor in adults. GBM is usually lethal within 24 months of diagnosis, despite aggressive multimodality treatment. Although it has been established that cancer-related inflammation is associated with worse outcomes, the role of eosinophils, basophils, atopy, and allergy in glioma biology is only gradually being delineated. In this study, we aimed to examine if eosinophil-based and basophil-based indices were altered in patients with GBM compared with healthy controls. We also aimed to study if there was any correlation between these indices and patient-related and tumor-related factors and survival. METHODS: This study was a retrospective analysis of prospectively maintained databases. Data pertaining to patient-related and tumor-related factors, hemograms, and survival data were obtained from the electronic medical records of selected patients. Correlations between eosinophil-based and basophil-based indices and these factors were studied, as was the association with overall survival. RESULTS: All the indices were altered in patients with GBM compared with normal healthy controls. The absolute eosinophil count was higher and the neutrophils/eosinophils ratio was lower in the better prognosis groups: those with better performance status; those without features of increased intracranial pressure or altered sensorium at presentation; those with ATRX-retained tumors that did not overexpress p53; and in the long-term survivors. The total lymphocyte count/basophils ratio and the absolute eosinophil count both independently predicted survival in a multivariate analysis. CONCLUSIONS: The absolute eosinophil count was consistently higher in the better prognosis groups and is likely to be incorporated into prognostic models for GBM.

Management dilemmas in pineoblastoma recurrence diagnosed during pregnancy.

Pineoblastoma is an extremely rare intracranial neoplasm, with increased risk of craniospinal metastasis. There is only one case reported in the literature who presented during pregnancy. Described here is a woman who presented at five months of gestation with recurrence of pineoblastoma, who had previously defaulted adjuvant therapy following surgical decompression. The challenges in the diagnosis and treatment of pineoblastoma and its effects on pregnancy are also discussed.

Analysis of Factors Associated with Long-Term Survival in Patients with Glioblastoma.

BACKGROUND: Some patients with glioblastoma multiforme (GBM) survive 3-5 years (or longer) after diagnosis. The goal of this study was to identify differences between the long-term survivors (LTS) and those who had a shorter overall survival (non-LTS groups). METHODS: This study was a retrospective analysis of prospectively maintained surgical databases. All patients who underwent safe maximal resection for GBM were included. Demographic, clinical, radiologic, and pathologic data were obtained from electronic medical records. Values of the biomarkers of systemic inflammation were computed from the preoperative hemogram reports. Patients with an overall survival (OS) ≥36 months were defined as the LTS group and were compared with the non-LTS groups (OS<36 months). RESULTS: Patients in the LTS group were younger, had a better baseline performance status, and were more likely to have undergone near- or gross-total resection. LTS was associated with lower Ki67 labeling, MGMT methylation, IDH mutation, and lack of p53 overexpression. Several novel findings were generated by this study. A longer pretreatment duration of symptoms was associated with a longer OS. Higher pretreatment levels of the absolute neutrophil count, neutrophil-lymphocyte ratio, monocyte-lymphocyte ratio, derived neutrophil-lymphocyte ratio and systemic index of inflammation, and lower levels of the absolute eosinophil count and eosinophil-lymphocyte ratio all correlated with a shorter OS. CONCLUSIONS: Several differences were identified between the LTS and non-LTS groups. These differences will likely be incorporated into future prognostic models. They may also aid in differentiation between recurrent disease and treatment-related changes.

Subcutaneous emphysema of the neck after shunt surgery for hydrocephalus in a case of metastatic ovarian cancer: illustrative case.

BACKGROUND: A 46-year-old female, a patient with a relapsed carcinoma in her ovary, had undergone ventriculoperitoneal (VP) shunt surgery for obstructive hydrocephalus due to vermian metastasis. Two weeks after the shunt surgery, she complained of discomfort in the neck. There was subcutaneous emphysema along the shunt track without tenderness or signs of inflammation. She was afebrile, and her vital parameters were stable. OBSERVATIONS: The authors ruled out pneumothorax and airway trauma as potential sources of emphysema. They tapped the shunt chamber and detected gram-negative bacilli. Ascitic fluid culture grew gas-forming Escherichia coli. LESSONS: Although some amount of air can get trapped in the subcutaneous plane during the tunneling procedure of a VP shunt tube insertion, the reappearance of a new, large column of air along the shunt track can be an ominous sign of shunt infection. The shunt became contaminated by bacteria of gut origin, which seeded the ascitic fluid, and a florid bacterial growth ascended up the shunt track, producing gas along the subcutaneous plane. Physicians should consider this rare etiology in their differential diagnoses of subcutaneous emphysema following VP shunt surgery.

Derivation of a Bleed to Brain Ratio to Predict the Need for Surgery in Head Injury.

BACKGROUND: The Monro-Kellie hypothesis states that the cranial compartment is incompressible, and cranial volume cannot expand. Human cranial volumes vary widely. However, the present guidelines for surgical evacuation are based on the volume of a single bleed. We hypothesized that the ratio of the total volume of blood clots in the brain to the volume of normal brain tissue must reflect the chances of developing increased intracranial pressure more accurately. OBJECTIVE: Compare the ratio of bleed volume to intracranial brain volume (bleed--brain ratio, BBR) in head trauma patients who had undergone surgery with those who did not require surgery. Estimate the cutoff value for this ratio that could predict the need for surgery. MATERIALS AND METHODS: An exact planimetric method using a Hounsfield unit bracketing strategy was used to derive total bleed volume and the intracranial volume in 212 head trauma patients. Receiver operating characteristics (ROC) curve was used to assess the predictive power of BBR for surgery. A cutoff value for the BBR with clinically significant sensitivity and specificity was estimated. RESULTS: The intracranial volume varied from 955 ml to a maximum of 1,525 ml. The total bleed volume and BBR was significantly different in the two groups. Using the ROC curve, we found that a BBR of 0.0535 had a sensitivity of 90.6% and a specificity of 52.6% to predict the need for surgery. CONCLUSIONS: We demonstrated that the BBR was superior to bleed volume alone in predicting the need for surgery. Although the ratio estimated by the tedious planimetric method was more accurate, an easier less precise method had reasonable accuracy and can be considered for everyday use. BBR could be particularly useful in those head trauma patients who have multiple irregular sized bleeds where the surgeon is undecided on the need for surgery.

How to Make a Do-It-Yourself, Disposable Bite Guard Using Easily Available Materials, to Prevent Tongue and Lip Injuries, During Motor Evoked Potential Monitoring in Neurosurgery.

We describe a do-it-yourself method of making a bite guard, using pairs of Foley catheters and surgical gloves to prevent tongue, lip, and other injuries during the monitoring of transcranially elicited motor evoked potential. We have used it in five cases, and have found that the hack is particularly cost-effective and reliable. We describe the technique here using multiple photographs.

The Xomed Monopolar Cranial Nerve Stimulator Electrode: A Surprising Handy Tool for Deep Dissection of Epidermoid Tumors.

Epidermoid cysts are notorious for their propensity to sneak into deep recesses between cranial nerves in the posterior fossa. Attempts to achieve complete excision using ordinary instruments when tempted by the seeming ease of dissection is known to cause unacceptable deficits. The Xomed monopolar stimulator electrode probe of the nerve integrity electromyography monitor has several advantages when used as the primary dissection tool for deep-seated epidermoid cysts. Cerebellopontine angle epidermoid is the classical prototype of a strategically placed deep-seated epidermoid tumor. The author describes the use of the monopolar stimulator electrode of the nerve integrity electromyography monitor as the primary dissection tool for excising epidermoid cysts of the cerebellopontine angle. Thin profile, rounded nontraumatic tip, and springiness of the body of the monopolar electrode aid the dissection. The monopolar electrode was used to tease and scoop out the flakes aided by a fine suction. An initial internal decompression allowed the capsule to be folded away and separated from neurovascular structures using the dissector. The thin profile of both the instruments allowed good visualization and delicate control over the dissection in depths of the resection cavity without undue traction or impacts on superficially dissected cranial nerves. This novel use of the monopolar electrode was employed in the surgical excision of epidermoid cysts of the cerebellopontine angle in nine patients. Total or near total excision was possible in eight of the nine patients who underwent excision using this technique. In three patients, mild deficits primarily of the fifth nerve sensory function were noted. The Xomed monopolar stimulating electrode of the nerve integrity electromyography monitor is an ideal instrument for deep dissection of epidermoid cysts in areas where neurovascular structures are at risk.

Growing Skull Fracture and the Orbitocranial Variant: Nuances of Surgical Management.

AIMS: Growing skull fracture (GSF) is a rare complication resulting from diastatic enlargement of a pediatric skull fracture. Orbitocranial GSF is a distinct variant with more complex management issues due to the displacement of the globe. This study aims to discuss surgical considerations in the management of GSF, with particular reference to orbitocranial variants. METHODS: We conducted a retrospective analysis of 7 children operated for GSFs at our institute from 2008 to 2015. RESULTS: Four boys and 3 girls were operated during this period. The mean age at initial trauma was 2 years, and most of them sustained falls. The most frequent symptoms of GSF were progressive scalp swelling and proptosis. The most common location was the orbitofrontal region. Duraplasty with cranioplasty was performed in 5 patients, while duraplasty alone was only required in 2 patients. A postoperative complication was noted in 1 patient and managed successfully. Good cosmetic results were obtained in all of the cases. CONCLUSIONS: Duraplasty is essential in the repair of GSF and should be followed by cranioplasty to prevent recurrent leptomeningeal herniation. We recommend the use of autologous bone from the surgical site for cranioplasty. Orbital roof repair is advisable for good visual and cosmetic outcome in orbitocranial variants of GSF.

Incidence of Potential Drug-Drug Interactions in a Limited and Stereotyped Prescription Setting - Comparison of Two Free Online Pharmacopoeias.

BACKGROUND: Drug-drug interactions (DDIs) are very common adverse events in health care delivery settings. The use of electronic pharmacopeias can potentially reduce the incidence of DDIs, but they are often thought to be cumbersome to use. This study is aimed at studying the incidence of potential DDIs in a surgical department, where a limited number of drugs are used in stereotyped combinations. We also compared two popular drug compendia in detecting potential DDIs. METHODS: The prescriptions of selected patients were entered into Epocrates® and Medscape® for Android smartphones. Potential DDIs were generated and their categories were noted. The warnings generated by Epocrates® were compared with those generated by Medscape® and an agreement index was calculated. RESULTS: Three hundred and thirty-one patients were included for analysis who had received a total of 2,878 drug orders. The incidence of potential DDIs was very high - 89% of all prescriptions. Phenytoin was the drug most commonly implicated, followed by furosemide. Of the DDIs detected, 0.14% were potentially serious and the drug combinations were contraindicated. There was a significant discrepancy between the categories of potential DDIs detected by Epocrates® and Medscape®. No clinically significant DDI was detected in any patient in this cohort. CONCLUSIONS: Despite routinely using only a limited number of drugs in stereotyped combinations, prescriptions in surgical departments may not be immune from a significant incidence of DDIs. The use of free apps could reduce the incidence of DDIs, enhance patient safety, and also aid in educating trainees.

Subclinical respiratory dysfunction in chronic cervical cord compression: a pulmonary function test correlation.

OBJECTIVE Respiratory abnormalities are well documented in acute spinal cord injury; however, the literature available for respiratory dysfunction in chronic compressive myelopathy (CCM) is limited. Respiratory dysfunction in CCM is often subtle and subclinical. The authors studied the pattern of respiratory dysfunction in patients with chronic cord compression by using spirometry, and the clinical and surgical implications of this dysfunction. In this study they also attempted to address the postoperative respiratory function in these patients. METHODS A prospective study was done in 30 patients in whom cervical CCM due to either cervical spondylosis or ossification of the posterior longitudinal ligament (OPLL) was diagnosed. Thirty age-matched healthy volunteers were recruited as controls. None of the patients included in the study had any symptoms or signs of respiratory dysfunction. After clinical and radiological diagnosis, all patients underwent pulmonary function tests (PFTs) performed using a standardized Spirometry Kit Micro before and after surgery. The data were analyzed using Statistical Software SPSS version 13.0. Comparison between the 2 groups was done using the Student t-test. The Pearson correlation coefficient was used for PFT results and Nurick classification scores. A p value < 0.05 was considered significant. RESULTS Cervical spondylotic myelopathy (prolapsed intervertebral disc) was the predominant cause of compression (n = 21, 70%) followed by OPLL (n = 9, 30%). The average patient age was 45.06 years. Degenerative cervical spine disease has a relatively younger onset in the Indian population. The majority of the patients (n = 28, 93.3%) had compression at or above the C-5 level. Ten patients (33.3%) underwent an anterior approach and discectomy, 11 patients (36.7%) underwent decompressive laminectomy, and the remaining 9 underwent either corpectomy with fusion or laminoplasty. The mean preoperative forced vital capacity (FVC) (65%) of the patients was significantly lower than that of the controls (88%) (p < 0.001). The mean postoperative FVC (73.7%) in the patients showed significant improvement compared with the preoperative values (p = 0.003). The mean postoperative FVC was still significantly lower than the control value (p = 0.002). The mean preoperative forced expiratory volume in 1 second (FEV1) (72%) of the patients was significantly lower than that of the controls (96%) (p < 0.001). The mean postoperative FEV1 (75.3%) in the cases showed no significant improvement compared with the preoperative values (p = 0.212). The mean postoperative FEV1 was still significantly lower than the control value (p < 0.001). The mean postoperative FEV1/FVC was not significantly different from the control value (p = 0.204). The mean postoperative peak expiratory flow rate was significantly lower than the control value (p = 0.01). The mean postoperative maximal voluntary ventilation was still significantly lower than the control value (p < 0.001). On correlating the FVC and Nurick scores using the Pearson correlation coefficient, a negative correlation was found. CONCLUSIONS There is subclinical respiratory dysfunction and significant impairment of various lung capacities in patients with CCM. The FVC showed significant improvement postoperatively. Respiratory function needs to be evaluated and monitored to avoid potential respiratory complications.

Measuring glioma volumes: A comparison of linear measurement based formulae with the manual image segmentation technique.

CONTEXT: Gliomas are irregular in shape unlike benign brain tumors like meningiomas or schwannomas. Simplifying assumptions about glioma geometry are therefore more likely to lead to wrong calculations of glioma volumes than for other tumors. AIMS: We compared simple linear measurement.based techniques of measuring glioma volume with manual region of interest.based image segmentation and to assess concordance. SETTINGS AND DESIGN: This study was a retrospective radiology archive-based study. SUBJECTS AND METHODS: The volumes of gliomas were measured by two assessors using five different techniques - manual image segmentation and four linear measurement-based formulae, which included the formulae for the volume of a sphere, cylinder, ellipsoid and its simplification v = abc/2. STATISTICAL ANALYSIS USED: Intra-ssessor concordance was evaluated using mean vs. difference. (Bland-Altman) plots and raw agreement indices. Inter-rater agreement was assessed by calculating the intra-class correlation coefficient for each technique. RESULTS: The best inter.rater concordance was for volume measured by manual segmentation. The tumor volumes measured using the formulae for volume of a sphere and cylinder had poor agreement with the planimetric volume and low inter.rater concordance. The formula for volume of an ellipsoid and its simplification had good agreement with the manual planimetric volume and had good inter.rater concordance. However, for larger tumors, the agreement with planimetric volume was poorer. CONCLUSIONS: Manual region of interest-based image segmentation is the standard technique for measuring glioma volumes. For routine clinical use, the simple formula v = abc/2 (or the formula for volume of an ellipsoid) could be used as alternatives.

Totally thrombosed giant anterior communicating artery aneurysm.

Giant anterior communicating artery aneurysms are rare. Apatient presented with visual dysfunction, gait ataxia and urinary incontinence. MRI showed a giant suprasellar mass. At surgery, the lesion was identified as being an aneurysm arising from the anterior communicating artery. The difficulty in preoperative diagnosis and relevant literature are reviewed.

Atlantoaxial dislocation in a patient with nonsyndromic symmetrical dwarfism: Report of a rare case.

Congenital anomalies of the craniovertebral junction (CVJ) are complex developmental defects. We describe a patient with atlantoaxial dislocation (AAD) and short stature whose morphopathologydid not fit into any of the previously described syndromic constellations. The patient underwent a reduction of the AAD followed by fixation with C1-C2 transarticular screws. Although numerous syndromes have been linked to both dwarfism and craniovertebral junction anomalies, this patient did not fit into any of these patterns. It is possible that this may be one of the many as yet unrecognized patterns of congenital anomalies.

An analysis of the citation climate in neurosurgical literature and description of an interfield citation metric.

BACKGROUND: The citation climate in neurosurgical literature is largely undefined. OBJECTIVE: To study the patterns of citation of articles in neurosurgery as a scientific field and to evaluate the performance of neurosurgery journals vis-à-vis journals in other fields. METHODS: References cited in articles published in neurosurgery journals during a specified time period were analyzed to determine the age of articles cited in neurosurgical literature. In the next analysis, articles published in neurosurgical journals were followed up for 13 years after publication. The postpublication citation patterns were analyzed to determine the time taken to reach the maximally cited state and the time when articles stopped being cited. The final part of the study dealt with the evolution of a new interfield citation metric, which was then compared with other standardized citation indexes. RESULTS: The mean ± SD age of articles cited in neurosurgical literature was 11.6 ± 11.7 years (median, 8 years). Citations received by articles gradually increased to a peak (at 6.25 years after publication in neurosurgery) and then reached a steady state; articles were still cited well into the late postpublication period. Neurosurgical articles published in nonneurosurgical high-impact journals were cited more highly than those in neurosurgical journals, although they took approximately the same time to reach the maximally cited state (7.2 years). The most cited pure neurosurgery journal was Neurosurgery. CONCLUSION: The citation climate for neurosurgery was adequately described. The interfield citation metric was able to ensure cross-field comparability of journal performance. ABBREVIATIONS: G1, group 1G2, group 2G3, group 3G4, group 4IFCM, interfield citation metric.

Multifocal spinal malignant peripheral nerve sheath tumor in an immunocompromised individual: case report and review of literature.

PURPOSE: Primary intraosseous spinal malignant peripheral nerve sheath tumor (MPNST) is exceedingly rare. MPNST with multifocal origin has been described to occur in the extremities. Such a lesion has not been described to occur in the spine. We describe a case of multifocal spinal MPNST and to review the literature relevant to this rare entity and its management. METHODS: A 40-year-old immunodeficient patient presented with rapidly progressive paraparesis and mid back ache. RESULTS: Despite aggressive surgical decompression, he developed multiple metastases 3 months after surgery. However, he remained stable for 1 year without any adjuvant therapy. Presently, he has received palliative radiotherapy for spinal recurrence and cerebral metastasis. CONCLUSION: Multifocal spinal MPNST is a rare lesion. In this instance, the multifocality of the disease and its odd location could be attributed to the immunodeficiency state. The prolonged survival could be due to an improvement in his immune status due to HAART.

Cerebral revascularization with superficial temporal - middle cerebral artery anastomosis for complete carotid occlusion: An emerging modality for preventing recurrent stroke.

Complete long segment carotid occlusion presents a treatment challenge. These patients cannot be managed adequately by endarterectomy or stenting. Despite best medical management, many continue to develop recurrent strokes. In this select group of patients, there may be role for flow augmentation techniques like superficial temporal-middle cerebral artery bypass. We report a patient who was thus successfully treated and remains asymptomatic. The relevant literature is reviewed.

Spinal aneurysms: clinicoradiological features and management paradigms.

OBJECT: Spinal aneurysms (SAs) are rare lesions. The clinicoradiological features and the exact degree of their association with comorbid conditions such as arteriovenous malformations (AVMs) and coarctation of the aorta have not been definitively described. The ideal management paradigm has not been established. The authors reviewed literature to determine the clinical patterns of presentation, management, and outcome of spinal aneurysms. METHODS: A systematic review of literature was performed using 23 separate strings. A total of 10,190 papers were screened to identify 87 papers that met the inclusion criteria. A total of 123 SAs could be included for analysis. RESULTS: The mean age of patients at presentation was 38 years; 10% of patients were aged less than 10 years and nearly 50% were greater than 38 years. Spinal aneurysms can be divided into 2 groups: those associated with AVMs (SA-AVMs, or Type 1 SAs) and those with isolated aneurysms (iSAs, or Type 2 SAs). Patients with Type 2 SAs were older and more likely to present with bleeding than those with Type 1 SAs. The acute syndromes can be divided into 3 groups of patients: those with spinal syndrome, those with cranial/craniospinal syndrome, and those with nonspecific presentation. Overall, 32.6% presented with angiography-negative cranial subarachnoid hemorrhage (SAH). Presentation with evidence of cord dysfunction (myelopathy/weakness/sensory loss/bladder involvement) correlated with poor outcome, as did presentation with hemorrhage and association with other comorbid conditions. Surgery and endovascular therapy both led to comparable rates of complete aneurysm obliteration for Type 2 SAs, whereas for the AVM-associated Type 1 SAs, surgery led to better rates of lesion obliteration. The authors propose a classification scheme for spinal aneurysms based on whether the lesion is solitary or is associated with a coexistent spinal AVM; this would also imply that the ideal therapy for the aneurysm would differ based on this association. CONCLUSIONS: The clinical and radiological patterns that influence outcome are distinct for Type 1 and Type 2 SAs. The ideal treatment for Type 1 SAs appears to be excision, whereas surgery and endovascular therapy were equally effective for Type 2 SAs.

Opportunistic Fonsecaea pedrosoi brain abscess in a patient with non-cirrhotic portal fibrosis-induced hypersplenism--a novel association.

Non-cirrhotic portal fibrosis, a common cause of splenomegaly in tropical countries, can lead to hypersplenism and pancytopenia. Hypersplenism in this setting has not been associated with opportunistic infections. We describe a patient with hypersplenism secondary to non-cirrhotic portal fibrosis who developed a Fonsecaea pedrosoi brain abscess and succumbed to the illness despite aggressive management.