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.

Resource utilization and convalescent care cost in neonatal opioid withdrawal syndrome.

BACKGROUND: Neonatal opioid withdrawal syndrome (NOWS) is a growing public health problem associated with complex and prolonged medical care and a significant resource utilization burden. The objective of this study was to compare the cost of different convalescent care settings for infants with NOWS. METHODS: Retrospective comparison study of infants with NOWS discharged directly from NICU, transferred to an acute care pediatric floor (PPCU) or rehabilitation hospital (PRH). Primary outcomes were length of stay (LOS) and cost of stay (COS). RESULTS: Infants had 1.3 (95% CI: 1.1,1.6) times and 2.5 (95% CI: 2.1,3.1) times significantly longer mean LOS for PPCU and RH discharges compared to NICU discharges. NICU discharged infants had the lowest mean COS ($25,745.00) and PRH the highest ($60,528.00), despite PRH having a lower cost per day. PRH discharged infants had higher rates of methadone and benzodiazepine and less buprenorphine exposure than NICU/PPCU discharged. Infants born to mothers on marijuana and buprenorphine had a 28% lower mean COS compared to unexposed infants. Median treatment cumulative morphine doses were six-fold higher for PRH than NICU discharge. CONCLUSIONS: Infants transferred to convalescence care facilities had longer and more costly admissions and received more medication. However, there may be a role for earlier transfer of a subset of infants at-risk for longer LOS as those exposed to methadone and/or benzodiazepines. Further studies exploring differences in resource utilization, convalescent care delivery and cost expenditure are recommended.

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.

Ethyl 2-cyano-2-{(Z)-2-[2,2-di-cyano-1-(4-methyl-phen-yl)eth-yl]cyclo-hexyl-idene}acetate.

In the title compound, C22H23N3O2, the cyclo-hexane ring adopts a chair conformation. The methyl-phenyl ring is oriented at an angle of 36.2 (1)° with respect to the best plane of cyclo-hexane moiety. In the crystal, mol-ecules associate via C-H⋯N hydrogen bonds, forming a three-dimensional network.

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.

Model-based evaluation of the efficacy and safety of nivolumab once every 4 weeks across multiple tumor types.

BACKGROUND: Nivolumab 480 mg every 4 weeks (Q4W) is approved in the European Union, United States, and several other markets across multiple tumor types. Its approval was supported by quantitative efficacy/safety analyses bridging to 3 mg/kg every 2 weeks (Q2W). PATIENTS AND METHODS: The benefit-risk profile of nivolumab 480 mg Q4W relative to 3 mg/kg Q2W was evaluated using population pharmacokinetic modeling and exposure-response (E-R) analyses for safety and efficacy. Pharmacokinetic exposures were predicted for 3203 patients with melanoma, non-small-cell lung cancer (NSCLC), renal cell carcinoma (RCC), squamous cell carcinoma of the head and neck, urothelial carcinoma, or classical Hodgkin lymphoma. Quantitative models analyzed E-R to predict 480-mg Q4W safety across all indications and efficacy for melanoma, NSCLC, and RCC. Intratumoral receptor occupancy (RO) was predicted for parameters representing different tumor types. RESULTS: Time-averaged concentrations for 480 mg Q4W versus 3 mg/kg Q2W were higher during the first 28 days (26.8%) and similar at steady state (5.2%). The maximum concentration (Cmax) after the first dose was higher (110.4%), and the trough concentration at day 28 was lower (-22.1%) with 480 mg Q4W versus 3 mg/kg Q2W. The Cmax achieved with 480 mg Q4W was lower than the previously established safe dose of 10 mg/kg Q2W. The probability of adverse events for key safety end points was similar for 480 mg Q4W and 3 mg/kg Q2W. The predicted overall survival and objective response rates with 480 mg Q4W were comparable to 3 mg/kg Q2W. The predicted high intratumoral RO provided additional evidence to support 480 mg Q4W across tumor types. CONCLUSIONS: The benefit-risk profile for nivolumab 480 mg Q4W was predicted to be similar to that of 3 mg/kg Q2W across tumor types while providing a convenient and flexible option for patients and their caregivers.

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.

Role of Decompressive Craniectomy in the Management of Cerebral Venous Sinus Thrombosis.

Cerebral venous sinus thrombosis (CVST) is a relatively uncommon cause of stroke more often affecting women and younger individuals. Blockage of the venous outflow rapidly causes edema and space-occupying venous infarctions and it seems intuitive that decompressive craniectomy (DC) can effectively reduce intracranial pressure just like it works for malignant middle cerebral artery infarcts and traumatic brain injury. But because of the relative rarity of this type of stroke, strong evidence from randomized controlled trials that DC is a life-saving procedure is not available unlike in the latter two conditions. There is a possibility that other forms of interventions like endovascular recanalization, thrombectomy, thrombolysis, and anticoagulation, which cannot be used in established middle cerebral artery infarcts and TBI, can reverse the ongoing pathology of increasing edema in CVST. Such interventions, although presently unproven, could theoretically obviate the need for DC when used in early stages. However, in the absence of such evidence, we recommend that DC be considered early as a life-saving measure whenever there are large hemorrhagic infarcts, expanding edema, radiological, and clinical features of impending herniation. This review gives an overview of the etiology and risk factors of CVST in different patient populations and examines the effectiveness of DC and other forms of interventions.

Complications of Decompressive Craniectomy.

Decompressive craniectomy (DC) has become the definitive surgical procedure to manage medically intractable rise in intracranial pressure due to stroke and traumatic brain injury. With incoming evidence from recent multi-centric randomized controlled trials to support its use, we could expect a significant rise in the number of patients who undergo this procedure. Although one would argue that the procedure reduces mortality only at the expense of increasing the proportion of the severely disabled, what is not contested is that patients face the risk of a large number of complications after the operation and that can further compromise the quality of life. Decompressive craniectomy (DC), which is designed to overcome the space constraints of the Monro Kellie doctrine, perturbs the cerebral blood, and CSF flow dynamics. Resultant complications occur days to months after the surgical procedure in a time pattern that can be anticipated with advantage in managing them. New or expanding hematomas that occur within the first few days can be life-threatening and we recommend CT scans at 24 and 48 h postoperatively to detect them. Surgeons should also be mindful of the myriad manifestations of peculiar complications like the syndrome of the trephined and neurological deterioration due to paradoxical herniation which may occur many months after the decompression. A sufficiently large frontotemporoparietal craniectomy, 15 cm in diameter, increases the effectiveness of the procedure and reduces chances of external cerebral herniation. An early cranioplasty, as soon as the brain is lax, appears to be a reasonable choice to mitigate many of the late complications. Complications, their causes, consequences, and measures to manage them are described in this chapter.

Exploring circulatory shock and mortality in viper envenomation: a prospective observational study from India.

BACKGROUND: Viper envenomation contributes to nearly 50% of snake-bite deaths in India, chiefly due to circulatory shock. The mechanisms leading to circulatory shock include bleeding, capillary leak syndrome (CLS) and myocardial depression. Pituitary-adrenal axis involvement in circulatory shock, though described, has not been fully elucidated. AIM: To identify predictors of circulatory shock and mortality in viper envenomation and explore the role of pituitary-adrenal axis in circulatory shock. DESIGN: Prospective hospital-based observational study. METHODS: Once a syndromic diagnosis of viper envenomation was made, relevant clinical and laboratory data were collected. Serum cortisol was estimated in those with circulatory shock. Post-mortem examination of pituitary, kidneys and adrenals was performed. Adjusted odds-ratios were calculated for respective risk-factors for shock and mortality using multivariable logistic regression with backward elimination strategy. RESULTS: Of 248 patients of viper envenomation treated at our hospital, circulatory shock was present in 19% and in-hospital mortality was 23%. CLS, circulatory shock, bleeding and requirement of > 20 vials of antivenom predicted mortality. Ischaemic and haemorrhagic necrosis of pituitary or adrenals was present in 51% of post-mortem specimens. Disseminated intravascular coagulation (DIC) and CLS were strong predictors of pituitary haemorrhage. CONCLUSION: Predictors of mortality - bleeding, CLS and requirement of high antivenom doses are warning signs which can alert clinicians to patients who may have poor outcomes. Our study points to a definite role of pituitary-adrenal axis in circulatory shock supports the hypothesis that pituitary involvement in viper envenomation closely resembles Sheehan syndrome. The mechanism of pituitary involvement appears to be a result of increased susceptibility of the swollen gland secondary to CLS and micro thrombi deposition in DIC.

Department of Neurosurgery, Madurai Medical College and the development of neurosurgery in South Tamil Nadu.

The development of neurosurgery in South Tamil Nadu can be traced to the Department of Neurosurgery, Madurai Medical College and Government Rajaji Hospital, Madurai, Tamil Nadu, India. The hospital was established in the year 1940 and Madurai Medical College was started in 1954. Prof. M. Natarajan founded this department in September, 1963. This department has a Neurosurgery Residency Program that is 50 years old. The establishment of this department and its growth to its present stature is documented here.

Unusual cause of high cervical myelopathy-C1 arch stenosis.

INTRODUCTION: High cervical myelopathy can be rarely caused by the developmental anomalies of atlas. Patients with C1 arch stenosis can present in early childhood or later in life. In symptomatic patients, posterior decompression at atlas is mandatory. We report the first clinical series of 20 patients of C1 arch stenosis in the English literature. MATERIALS AND METHODS: This is retrospective case series having a cohort of 20 patients with congenital C1 arch stenosis. RESULTS: There were 12 pediatric (age <18 years) and 8 adult patients. Mean age was 22.85 years. Syndromic association was seen in four patients. Following decompressive surgery, these patients noticed a symptomatic improvement. CONCLUSIONS: Isolated C1 arch stenosis is a surgically curable rare cause of high cervical myelopathy and responds well to surgery.

Brain abscess and cervical lymphadenitis due to Paraclostridium bifermentans: A report of two cases.

Paraclostridium bifermentans (current nomenclature of Clostridium bifermentans since 2016) is a gram-positive, spore-forming anaerobic bacterium. Here, we describe two cases associated with this organism. The first, primarily a case of tubercular brain abscess where P. bifermentans was isolated as part of a polymicrobial flora, following a neurosurgical procedure for the same and the second, a case of cervical lymphadenitis from which it was isolated as the sole causative agent. There are only a few reported cases of P. bifermentans in literature and these cases illustrate the widening spectrum of infections related to it.

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.