Sanjay Gupta

OBJECT: Standard techniques for pedicle screw fixation of the lumbar spine involve open exposures and extensive muscle dissection. The purpose of this study was to report the initial clinical experience with a novel device for percutaneous posterior fixation of the lumbar spine. METHODS: An existing multiaxial lumbar pedicle screw system was modified to allow screws to be placed percutaneously by using an extension sleeve that permits remote manipulation of the polyaxial screw heads and remote engagement of the screw-locking mechanism. A unique rod-insertion device was developed that linked to the screw extension sleeves, allowing for a precut and -contoured rod to be placed through a small stab wound. Because the insertion device relies on the geometrical constraint of the rod pathway through the screw heads, minimal manipulation is required to place the rods in a standard submuscular position, there is essentially no muscle dissection, and the need for direct visual feedback is avoided. Twelve patients (six men and six women) who ranged in age from 23 to 68 years underwent pedicle screw fixation in which the rod-insertion device was used. Spondylolisthesis was present in 10 patients and osseous nonunion of a prior interbody fusion was present in two. All patients underwent successful percutaneous fixation. Ten patients underwent single-level fusions (six at L5-S1, three at L4-5, and one at L2-3), and two underwent two-level fusions (one from L3-5 and the other from L4-S1). The follow-up period ranged from 10 to 19 months (mean 13.8 months). CONCLUSIONS: Although percutaneous lumbar pedicle screw placement has been described previously, longitudinal connector (rod or plate) insertion has been more problematic. The device used in this study allows for straightforward placement of lumbar pedicle screws and rods through percutaneous stab wounds. Paraspinous tissue trauma is minimized without compromising the quality of spinal fixation. Preliminary experience involving the use of this device has been promising.

The ability of interferon gamma (IFN-gamma) to inhibit the proliferation of type 2 T helper cells (TH2), but not that of type 1 (TH1) cells, suggests that helper cell subsets might differ in their activation of the IFN-gamma signaling pathway. The IFN-gamma-inducible signal transducing factor (STF-IFN gamma) was activated in murine TH2 but not in TH1 cell clones, because in the latter the second chain of the IFN-gamma receptor (accessory factor 1 or IFN-gamma R beta) was absent. Thus, TH1 cells use receptor modification to prevent the activation of STF-IFN gamma and achieve an IFN-gamma-resistant state.

OBJECTIVE: Prophylactic therapies have demonstrated efficacy in reducing the incidence of deep venous thrombosis (DVT) in neurosurgical patients. Retrospective analysis of patients undergoing neurosurgical procedures at the University of Michigan demonstrated a high incidence (14%) of postoperative DVT among patients with intracranial neoplasms treated with sequential compression device (SCD) prophylaxis alone. Therefore, we investigated the efficacy and safety of the low-molecular weight heparin enoxaparin in preventing DVT in patients with brain tumors. The goal of the study was to compare SCD, enoxaparin, and combined SCD/enoxaparin prophylaxis among patients requiring surgery for treatment of intracranial neoplasms. METHODS: Eligible patients were randomized to SCD, enoxaparin, or combined therapy. Treatment was initiated before the induction of anesthesia and was continued throughout the hospital stay. Patients were screened for DVT, using duplex imaging, on four occasions in the first 1 month after surgery. The incidences of DVT and serious adverse events were compared between groups using analysis of variance and the Dunnet two-sided t test. RESULTS: Sixty-eight patients completed the study. Postoperative DVT occurred in 3 of 22 (13.6%) SCD-treated patients, 1 of 23 (4.3%) enoxaparin-treated patients, and 4 of 23 (17.4%) SCD/enoxaparin-treated patients. Differences were not statistically significant. Postoperative intracranial hemorrhage did not occur in patients in the SCD-treated group, whereas 5 of 46 patients receiving low-molecular weight heparin suffered clinically significant intracranial hemorrhage. The study was terminated because of the increased incidence of adverse events in the enoxaparin-treated groups. CONCLUSION: Enoxaparin therapy initiated at the time of anesthesia induction increases postoperative intracranial hemorrhage.

Alternaria is an important fungus to study due to their different life style from saprophytes to endophytes and a very successful fungal pathogen that causes diseases to a number of economically important crops. Alternaria species have been well characterized for the production of different host-specific toxins (HSTs) and non-host specific toxins (nHSTs) which depend upon their physiological and morphological stages. The pathogenicity of Alternaria species depends on host susceptibility or resistance as well as quantitative production of HSTs and nHSTs. These toxins are chemically low molecular weight secondary metabolites (SMs). The effects of toxins are mainly on different parts of cells like mitochondria, chloroplast, plasma membrane, Golgi complex, nucleus, etc. Alternaria species are produced from several nHSTs such as brefeldin A, tenuazonic acid, tentoxin and zinniol. HSTs that act in very low concentrations affect only certain plant varieties or genotype and play a role in determining the host range of specificity of plant pathogens. The commonly known HSTs are AAL-, AK-, AM-, AF-, ACR- and ACT-toxins which are named by their host specificity and these toxins are classified into different family groups. The HSTs are differentiated on the basis of bio-statistical and other molecular analyses. All these toxins have different mode of action, biochemical reactions and signalling mechanisms to cause diseases. Different species of Alternaria produced toxins which reveal its biochemical and genetic effects on itself as well as on its host cells tissues. The genes responsible for the production of HSTs are found on the conditionally dispensable chromosomes (CDCs) which have been well characterized. Different bio-statistical methods like BLAST data analysis used for the annotation of gene prediction, pathogenicity-related genes may provide surprising knowledge in present and future.

OBJECT: Standard techniques for lumbar pedicle screw fixation involve open exposures and extensive muscle dissection. The purpose of this study was to report the initial clinical experience with a novel device for percutaneous posterior fixation of the lumbar spine. METHODS: An existing multiaxial lumbar pedicle screw system was modified so that screws could be placed percutaneously by using an extension sleeve that would allow for remote manipulation of the polyaxial screw heads and remote engagement of the screw locking mechanism. A unique rod insertion device was developed that linked to the screw extension sleeves, allowing for a precut, precontoured rod to be placed through a small stab wound. Because the insertion device relies on geometrical constraint of the rod pathway through the screw heads, rods can be placed in a standard submuscular position with minimal manipulation, essentially no muscle dissection, and without the need for direct visual feedback. Twelve patients (six men and six women who ranged in age from 23-68 years) underwent pedicle screw fixation in which the rod insertion device was used. Spondylolisthesis was present in 10 patients and nonunion of a prior interbody fusion was present in two. All patients underwent successful percutaneous fixation. Ten patients underwent single-level fusions (six at L5-S1, three at L4-5, and one at L2-3), and two underwent two-level fusions (one from L-3 to L-5 and the other from L-4 to S-1). The follow-up period ranged from 3 to 12 months (mean 6.8 months). CONCLUSIONS: Although percutaneous lumbar pedicle screw placement has been described previously, longitudinal connector (rod or plate) insertion has been more problematic. The device used in this study allows for straightforward placement of lumbar pedicle screws and rods through percutaneous stab wounds. Paraspinous tissue trauma is minimized without compromising the quality of spinal fixation. Preliminary experience with this device has been promising.