Correlation of Preoperative Functional Magnetic Resonance Imaging (fMRI) with Intraoperative Cortical Stimulation in Surgeries of Eloquent Brain Lesions.

Background: Direct Cortical Stimulation (DCS) represents the gold standard for mapping of eloquent brain cortex. However, DCS is an invasive and time-consuming procedure. fMRI has become a useful tool to delineate motor and sensory eloquent cortex from the areas of planned neurosurgical resection. In our study, we will be studying the reliability of preoperative imaging when compared with the intraoperative DCS. Objectives: The aim of this study was to assess the reliability of fMRI by comparing it with DCS. Methods and Materials: Thirty patients with eloquent cortex lesions were admitted. Preoperative fMRI sequences were loaded into a neuro-navigational system. Intraoperative motor mapping was done by DCS. The location of all cortical stimulated points was correlated with the cortical functional structures. Based on it, specificity, sensitivity, positive predictive value, negative predictive value of fMRI was calculated. Preoperative and postoperative Karnofsky score and MRC grading was then noted. Results: Concordance between fMRI and DCS was noted in 26 cases. Overall mean sensitivity, specificity, positive and negative predictive value of fMRI as compared to DCS was 95%, 92.48%, 85.56%, and 96.08%, respectively. Preoperative and Postoperative Karnofsky score stayed same in most of the cases [25/30]. Conclusions: DCS remains the gold standard for mapping eloquent cortex in-spite of its invasiveness, side effects such as seizures and cost concerns. Although fMRI cannot replace DCS, it can guide and increase the efficacy in resection, select high-risk patients for intraoperative monitoring, help in preoperative stratification of risk counseling and preservation of neurological status in eloquent brain lesions.

A comparison of Adult and Pediatric Hydrocephalus.

Hydrocephalus is a common clinical problem encountered in neurosurgical practice. With greater subspecialisation, pediatric neurosurgery has emerged as a special discipline in several countries. However, in the developing world, which inhabits a large pediatric population, a limited number of neurosurgeons manage all types of hydrocephalus across all ages. There are some essential differences in pediatric and adult hydrocephalus. The spectrum of hydrocephalus of dysgenetic origin in a neonate and that of normal pressure hydrocephalus of the old age has a completely different strategy of management. Endoscopic third ventriculostomy outcomes are known to be closely associated with age at presentation and surgery. Efficacy of alternative pathways of CSF absorption also differs according to age. Managing this disease in various age groups is challenging because of these differences in etiopathology, tempo of the disease, modalities of investigations and various treatment protocols as well as prognosis.

Contralateral hearing loss and facial palsy in an operated case of vestibular schwannoma-Case report.

INTRODUCTION: Contralateral ear hearing loss (CHL) is an extremely rare but a potentially devastating complication in a patient with already compromised hearing due to a Vestibular schwannoma (VS). Our patient had CHL accompanied by contralateral facial palsy. Our case is only the second case reported in literature to the best of our knowledge. PRESENTATION OF CASE: A 55-year elderly male presented with right sided sensorineural hearing loss, cerebellar signs and Grade II House & Brackmann (H&B) facial nerve weakness for last1-year. Magnetic resonance imaging (MRI) scan revealed a large right sided vestibular schwannoma (VS) with severe compression of the ipsilateral pons. The pre-operative pure tone audiometry (PTA) documented severe sensory neural hearing loss (SNHL) on the right side along with mild SNHL on the left side. A right retromastoid suboccipital craniotomy was performed and VS was completely excised. The ipsilateral facial nerve was preserved anatomically. On the 4th post-operative day he developed severe pain and tinnitus in left ear. In the next 24-h there were hearing loss and grade II facial nerve paresis. The PTA done on the 5th post-operative day revealed severe SNHL on both sides. He was managed conservatively with steroids and vasodilators. At 6-months of follow-up the left side hearing loss and facial weakness had significantly recovered. The PTA showed significant improvement in the left side SNHL DISCUSSION: Contralateral hearing disturbance with contralateral facial palsy after acoustic neuroma surgery is extremely rare. The exact etiopathogenesis of this unusual phenomenon is not clear and various theories have been proposed. There is no standard recommendation for treatment of these rare complications and the etiology remains obscure. CONCLUSION: Hearing loss and facial palsy on the contralateral side after VS surgery is extremely rare. It is imperative that this rare complication should be considered following VS surgery.

Obstructive sleep apnea and chronic opioid use.

The use of opioids has been associated with development of sleep-disordered breathing, including central apneas, nocturnal oxygen desaturations, and abnormal breathing patterns. We describe sleep-disordered breathing and its subsequent treatment in a group of obstructive sleep apneic patients on chronic opioid therapy. Clinical evaluation followed by diagnostic overnight polysomnogram was performed in subjects on chronic opioid therapy who met the study criteria. All subjects had an initial CPAP titration followed by a repeat clinical evaluation. Subjects with an apnea-hypopnea index (AHI) ≥ 5 continued to report symptoms and had follow-up titration with bilevel positive therapy; then bilevel positive-pressure therapy with a back-up rate was then performed. Age-, sex-, and disease-severity-matched obstructive sleep apnea patients served as controls. Forty-four study participants, including a large group of women (50%), and 44 controls were enrolled in the study. Opioid subjects had AHI = 43.86 ± 1.19, with a central apnea index of 0.64 ± 1.36. Two abnormal breathing patterns were seen, including decreased inspiratory effort during an obstructive event and longer than expected pauses in breathing. Despite adequate titration with CPAP and bilevel positive-pressure therapy, nocturnal awakenings and central apnea awakenings persisted (AHI and central apnea indices of 13.81 ± 2.77 and 11.52 ± 2.12, respectively). Treatment with bilevel positive-pressure therapy with a back-up rate controlled the problem. Nonobese OSA patients with opioid intake have obstructive breathing with a different pattern. In this study, bilevel positive-pressure therapy with a back-up rate was the most effective treatment.