Ashish Kumar

Free Space Optical Communication System under Different Weather Conditions

Over the last two and half decades Free Space Optical (FSO) communication is preferred over the radio frequency communication and microwave systems because of its license-free long-range operations. Also it is having many advantages like small size, high bandwidth, low cost and lease of deployment. Free Space Optical communication has few limitations also like beam dispersion, scintillation etc. A well known limitation of FSO is the effect of weather conditions on it. In this paper we have designed a 2.5 Gbps FSO system and presented analysis of 2.5 Gbps FSO system with different weather condition by distance of 9 km. From the result it is clear as we move from clear weather to heavy fog Q factor as well as transmission range will decrease.

Keraunoparalysis: What a neurosurgeon should know about it?

Keraunoparalysis or transient weakness in limbs following a lightning strike has been well described in literature. Many times, neurosurgeons encounter patients with paraparesis secondary to trauma in the setting of a lightning strike. In these cases, it becomes imperative to find out the true cause behind such weakness in lower limbs because the prognosis differs significantly depending on the etiology. We report a case of keraunoparalysis affecting both lower limbs in a 50-year-old male, where he recovered within 48 hours of the impact. As far as our knowledge is concerned, this is the first case of keraunoparalysis reported from India. We also review the available literature and discuss the physics of lightning, its mechanism, other clinical presentations, and management strategy in the light of our case. These patients must be investigated for other possible causes of paraparesis secondary to trauma and keraunoparalysis should rather be a diagnosis of exclusion, only to be confirmed on imageology. Awareness regarding similar cases will make neurosurgeons notice this entity early, avoiding unnecessary investigation, and hence they will be able to prognosticate in the most efficient manner.

Silent neurenteric cyst with split cord malformation at conus medullaris: Case report and literature review.

Split cord malformations (SCM) are a common pediatric abnormality where children present with features of tethering and backache along with varying neurological deficits. Multiple neural tube defects may co-exist in children having defects of primary and/or secondary neurulation. Co-existent neurenteric cysts along with type 1 SCM have been described very rarely in the literature. We report a case of silent neurenteric cyst at conus medullaris with SCM type 1 where the cyst was missed in the preoperative imaging. Until date, only 8 such cases of neurenteric cysts with SCM at lumbar region have been reported. We review the literature regarding co-existing dual pathologies of neurenteric cysts and type 1 SCMs in light of limited capacity of imaging modalities to detect small neurenteric cysts in presence of co-existent neural tube defects. Multiple spinal neural tube defects in children need more attention and precise microneurosurgical skills as management differs in each of them. Co-existence of such pathologies detected intra-operatively may need modifications in preoperative planning to achieve the best possible outcomes.

A novel case of “ambulatory” cervical spondyloptosis: case report with literature review

BackgroundCervical spondyloptosis is an extreme variant of cervical spinal injury where patients usually present with disabling neurological deficits. Presentation of these patients without significant morbidity is very rare and we could only find sporadic case reports in literature involving traumatic cervical spondyloptosis without neurological deficits. Usually such patients get spared due to expansion of spinal canal after fracture of posterior vertebral elements.Case summaryWe report a case of traumatic C5/C6 spondyloptosis in an ambulatory patient despite having an intact posterior vertebral arch. This patient was managed successfully with anterior cervical fusion.ConclusionTo the best of our knowledge, this is the first case report of its kind as it exemplifies the rarity of such an occurrence and underlines the importance of timely management to maintain such preserved neurological status.

Posterior approach for giant S1 neurofibroma in Von Recklinghausen's disease: Is total resection realistic?

Bilateral sacral neurofibromas are uncommonly seen in neurofibromatosis type 1 (NF1) also known as Von Recklinghausens disease. They often grow to enormous dimensions before detection owing to bone scalloping. Resections of “giant” S1 neurofibromas are difficult due to the limitations of operative window in sacrum and critical functions associated with S1 nerve root. We report a case of bilateral S1 neurofibromas in a patient of NF1 where she had a giant left-sided neurofibroma with extensive bone erosion and a small fusiform neurofibroma on the right side. The tumor was excised completely on the left and near totally on the right side via posterior approach. There were no postoperative neurological deficits and the patient recovered well. Usually, complete excision harbors the chances of postoperative neurological deficits due to the eloquence of the nerve root involved and complete resection without significant morbidity seems unrealistic. However, excision of giant ones may not result in grave deficits always if the patient is neurologically intact before surgery. Also, in selected patients, only posterior approach may suffice for giant neurofibromas with extensive bone scalloping and complete removal can be attempted successfully despite narrow corridors.

Prognostic value of cerebrospinal fluid lactate in meningitis in postoperative neurosurgical patients

Objective: To evaluate the prognostic usefulness of cerebrospinal fluid (CSF) lactate in postoperative bacterial meningitis (POBM) and to establish the optimal CSF lactate cut-off values in our population to identify POBM in neurosurgical patients. Patients and Methods: A prospective study of postoperative neurosurgical patients with presumed and established bacterial meningitis in the Department of Neurosurgery, NIMS, Hyderabad, India, from September 2012 to December 2014. The diagnostic and prognostic values of CSF lactate have been evaluated and compared with other well-established CSF markers. All the patients who have undergone intradural cranial surgery with features of meningism have been included. Results: The study included 37 patients. The CSF value of the first lumbar puncture (LP) was taken to evaluate the diagnostic value of CSF lactate. Twenty three corresponded to Group A, and 14 to Group B. The mean CSF lactate in Group A was 5.94 ± 2.36, and in Group B 4.60 ± 2.31. Subsequent LPs were performed and CSF analyzed to evaluate the prognostic value of CSF lactate. The CSF markers like neutrophil count (P = 0.003), CSF/blood glucose ratio (P = 0.012), CSF lactate (P = 0.024), lymphocyte count (P = 0.046), leukocyte count (P = 0.047) have shown their prognostic value in a descending order. CSF markers like the presence of red blood cells (P = 0.540) and proteins (P = 0.757) did not show prognostic significance. The decline in CSF lactate (content and concentration) after initiation of antibiotics correlated with subsidence of fever (P = 0.0001), decrease in neck rigidity (P = 0.022) and improvement in sensorium. They were also correlated improvement in CSF/blood glucose ratio and CSF white blood cell counts. Conclusions: In our study, CSF lactate was noted to have a dependable prognostic value in POBM. As routine CSF markers can be ambiguous in POBM, CSF lactate can be considered a better alternative for both establishing the diagnosis and prognostication.

Variability among Isolates of Rhizoctonia solani Inciting Web Blight of Mungbean

Web blight of Mungbean (Vigna radiata L.) caused by Rhizoctonia solani Kühn (Teleomorph: Thanatephorus cucumeris (Frank) Donk) is an economically important disease which reduces 33 to 40 per cent grain yield and 28.6 per cent in 1000 grain weight at different level of disease severity and in different varieties of mungbean (Singh et al., 2012 and Gupta et al., 2010) due to destruction of leaves or seed blemishes that reduces its value.

Psychiatric disorders in low backache patients: A neurosurgeon's nightmare!!!

© 2016 Asian Journal of Neurosurgery | Published by Wolters Kluwer ‐ Medknow LBA without neural compression for the underlying psychiatric/ psychological disorders. Many case studies have been published on this critical issue, but not in the neurosurgical literature. Hence, most of us often either neglect or are not even aware of the impact of psychological factors associated with LBA. Christensen et al. recently surveyed Danish population suffering from chronic LBA and compared their degree of mental stress as compared to general population. They inferred that self-reported symptoms of somatization, anxiety, phobic anxiety, obsessive-compulsive, depression, and hostility are all more common among patients with low back pain compared to the general population. Similarly, literature also has evidence of the cognitive deficits caused by chronic LBA and moreover, getting worse after long-term opioid intake. Single-photon emission computed tomography images have also revealed the brain blood flow alterations in the patients with LBA affecting the prefrontal cortex primarily. Hence, we can for sure conclude that LBA is not restricted just to the back as chronic pain often leads to changes in its cerebral perception and which may also be indirectly related to the various psychiatric disorders.

Revealing the hidden: Delight of susceptibility weighted imaging for neurosurgeons!

Asian Journal of Neurosurgery Vol. 11, Issue 3, July‐September 2016 temporoparietal craniotomy and excision of lesion along with clot evacuation was performed. Histopathological examination confirmed it as cavernous hemangioma. We also performed susceptibility weighted imaging (SWI) on our patient after the second surgery [Figure 4] and as many as eight new lesions were detected, which were missed in routine MRI and could have bled in future. Screening of his parents, siblings and children with SWI was negative for familial cavernomas, although genetic analysis could not be performed.

NIMS technique for minimally invasive spinal fixation using non-fenestrated pedicle screws: A technical note.

Study Design: Case series. Objective: To reduce the cost of minimally invasive spinal fixation. Background: Minimally invasive spine (MIS) surgery is an upcoming modality of managing a multitude of spinal pathologies. However, in a resource-limited situations, using fenestrated screws (FSs) may prove very costly for patients with poor affordability. We here in describe the Nizam′s Institute of Medical Sciences (NIMS) experience of using routine non-FSs (NFSs) for transpedicular fixation by the minimally invasive way to bridge the economic gap. Materials and Methods: A total of 7 patients underwent NFS-minimally invasive spine (MIS) surgery. Male to female distribution was 6:1. The average blood loss was 50 ml and the mean operating time was 2 and 1/2 h. All patients were mobilized the very next day after confirming the position of implants on X-ray/computed tomography. Results: All 7 patients are doing well in follow-up with no complaints of a backache or fresh neurological deficits. There was no case with pedicle breach or screw pullout. The average cost of a single level fixation by FS and NFS was `1, 30,000/patient and `32,000/patient respectively (