Transarticular screw fixation using neuronavigation: Technique

<b>Background:</b> Transarticular screw placement needs highly accurate imaging. We assess the efficacy and accuracy of C1-C2 transarticular screw fixation using neuronavigation and also cast a technical note on the procedure. <b> Materials and Methods:</b> This study included a total of nine patients who underwent transarticular screw fixation using the neuronavigation system. A total of 15 screws were placed. All patients underwent postoperative CT scan with 3-Dimensional (3-D) reconstruction to check for the accuracy of implantation. <b> Results:</b> One patient had encroachment of the transverse foramen but there was no vertebral artery injury. There were no clinical complications or adverse sequelae. <b> Conclusion:</b> Neuronavigation is extremely helpful in C1-C2 transarticular screw fixation and gives excellent accuracy

A comparative study to assess the effect of amikacin sulfate bladder wash on catheter-associated urinary tract infection in neurosurgical patients

Background: The indwelling urinary catheter is an essential part of modern medical care. Unfortunately, when poorly managed, the indwelling catheter may present a hazard to the very patients it is designed to protect. Catheter-associated urinary tract infection (CAUTI) is the most common nosocomial infection in hospitals and nursing homes. Aims and Objectives: The primary objective was to study the effect of amikacin sulfate bladder wash on CAUTI in neurosurgical patients. The other objectives were to study the various organisms causing CAUTI and their antibiotic sensitivity and resistance pattern. Materials and Methods: This was a prospective randomized controlled study performed on 60 patients who met the inclusion criteria at the neurosurgical intensive care of the All India Institute of Medical Sciences between June and December 2006. The patients were randomized into two groups - one was the trial group which received amikacin bladder wash, while the other was the control group that did not receive any bladder wash. Results: Forty percent of the subjects in the control group developed CAUTI, while none of the subjects in study group developed CAUTI. (Fisher′s exact test, P value < 0.001) Pseudomonas aeruginosa (51%) was the commonest pathogen. Conclusions: Amikacin sulfate bladder wash was effective in preventing CAUTI. It can thus decrease the antibiotic usage thereby preventing the emergence of antibiotic resistance. DOI: 10.4103/0972-5229.5311

Assessment of 1p/19q status by fluorescence in situ hybridization assay: A comparative study in oligodendroglial, mixed oligoastrocytic and astrocytic tumors

Background : Due to overlapping histomorphological features, difference in clinical behavior and treatment response, establishing potential molecular markers to facilitate diagnosis of various genetic subtypes of diffuse gliomas is essential. Aim : To analyze 1p/19q status in diffuse gliomas and correlate it with epidermal growth factor receptor (EGFR) and p53 protein expression. Materials and Methods : 1p/19q status in 43 cases was evaluated by fluorescence in situ hybridization assay. Glial fibrillary acidic protein (GFAP), EGFR and p53 were assessed by immunohistochemistry. Results : Glial fibrillary acidic protein immunopositivity was observed in oligodendrogliomas within minigemistocytes and gliofibrillary oligodendrocytes as perinuclear homogenous blobs. It also highlighted the intermingled reactive astrocytes. Astrocytomas and the astrocytic component of oligoastrocytomas showed a diffuse fibrillary type of staining. 1p and/or 19q loss was seen in 65% (13/20) of oligodendrogliomas and 66.6% (5/9) of mixed oligoastrocytomas. There was one case each of pediatric oligodendroglioma and mixed oligoastrocytoma, none of which showed 1p/19q loss. None of the astrocytomas including two pediatric cases showed this alteration (P < 0.05). p53 was expressed in 57.1% of astrocytomas (8/14), 33% of mixed oligoastrocytomas (3/9) and 10% of oligodendrogliomas (2/20). Majority of oligodendrogliomas (85%; 17/20) and oligodendroglial areas in mixed oligoastrocytomas (77.7%; 7/9) showed a membranous lace-like immunopositivity with EGFR. In contrast, all astrocytomas (Grade II and III) were EGFR negative. Conclusion : Loss of 1p/19q is strongly associated with oligodendroglial phenotype, while astrocytic tumors are more likely to show p53 over-expression. p53 expression and 1p/19q status appear to be mutually exclusive

Predictive factors for early symptomatic recurrence in pilocytic astrocytoma: does angiogenesis have a role to play?

We studied predictive factors with respect to angiogenesis and proliferative indices for early symptomatic recurrences in patients with pilocytic astrocytoma (PA). One hundred and eighteen patients who underwent surgery for PA were divided into non-recurrent and early symptomatic recurrence groups to analyze clinicoradiological and immunohistopathological (n=33) parameters. Patients with non-recurrent tumors presented with synptoms for a mean duration of 10.2 ± 9.1 months while those with recurrent tumors presented slightly earlier (6.9 ± 4.5 months). Common tumor locations were the cerebellum (38.1%), optic chiasm (27.9%), supratentorial region (19.4%) and brainstem (9.3%). Recurrent tumors were mostly located in the cerebellum (44%) and brainstem (33%). Strong contrast enhancement was noted in 70 (59.3%) tumors, while 48 (40.7%) showed poor contrast. Resection was complete in 53% of patients while near total excision was achieved for the remaining patients. Cellularity and plemorphism were similar in both groups. Extensive endothelial proliferation was observed in 18.1% of patients while the remainder showed a focal pattern. Diffuse vascular endothelial growth factor (VEGF) expression was observed in 36.3% of patients while 63.6% showed mild-to-moderate focal expression. Endothelial proliferation and VEGF expression were more pronounced in patients with non-recurrent tumors, but this was not statistically significant. MIB-I labeling indices were similar (1-5%) for both groups. Symptomatic recurrences were common in infratentorial PAs. Radiology, histopathology and proliferative indices did not offer any prognostic information. Angiogenesis markers such as endothelial proliferation and VEFG expression did not predict early symptomatic recurrence. Diffuse VEGF expression and endothelial proliferation were observed in tumors that showed strong contrast enhancement

Satellite Communications in the New Space Era:A Survey and Future Challenges

Satellite communications (SatComs) have recently entered a period of renewed interest motivated by technological advances and nurtured through private investment and ventures. The present survey aims at capturing the state of the art in SatComs, while highlighting the most promising open research topics. Firstly, the main innovation drivers are motivated, such as new constellation types, on-board processing capabilities, nonterrestrial networks and space-based data collection/processing. Secondly, the most promising applications are described i.e. 5G integration, space communications, Earth observation, aeronautical and maritime tracking and communication. Subsequently, an in-depth literature review is provided across five axes: i) system aspects, ii) air interface, iii) medium access, iv) networking, v) testbeds & prototyping. Finally, a number of future challenges and the respective open research topics are described