We examined cytokine‐mediated neuronal death in neuron‐astrocyte cultures from second trimester human fetal cerebrum. In these cultures, high‐output inducible nitric oxide synthase (NOS) and tumor necrosis factor‐α (TNFα) are expressed in astrocytes after exposure to IL‐1β/IFNγ. Neuronal cell death was evident at ≥48 h following cytokine stimulation. Neutralizing anti‐TNFα antiserum inhibited (≈48%) neurotoxicity in IL‐1β/IFNγ‐treated cultures, demonstrating a role for endogenously produced TNFα. Interestingly, the degree of neuroprotection conferred by superoxide dismutase or N‐methyl D‐aspartate (NMDA) receptor antagonists in these cultures was smaller and variable. Similarly, the effect of the NOS inhibitor, NG‐monomethyl L‐arginine (NMMA) on IL‐1β/IFNγ‐induced neuronal death was variable, showing no statistically significant effect when results from more than 30 independent cultures were averaged. Neurons die by apoptosis in cytokine‐treated human fetal CNS cultures as shown by the characteristic nuclear morphology as well as positive labeling for TUNEL. Our results demonstrate a potent neurotoxicity mediated by the cytokine combination IL‐1β/IFNγ in primary human neuron‐astrocyte cultures and a crucial role for endogenous TNFα in mediating neurotoxicity in this system. These results firmly establish the neurotoxic potential of the inflammatory cytokines IL‐1β and TNFα in the human CNS. GLIA 28:114–127, 1999. © 1999 Wiley‐Liss, Inc.

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Minimally invasive spine surgery is becoming more common in the treatment of adult lumbar degenerative disorders. Minimally invasive techniques have been utilized for multilevel pathology, including adult lumbar degenerative scoliosis. The next logical step is to apply minimally invasive surgical techniques to the treatment of adolescent idiopathic scoliosis (AIS). However, there are significant technical challenges of performing minimally invasive surgery on this patient population. For more than two years, we have been utilizing minimally invasive spine surgery techniques in patients with adolescent idiopathic scoliosis. We have developed the present technique to allow for utilization of all standard reduction maneuvers through three small midline skin incisions. Our technique allows easy passage of contoured rods, placement of pedicle screws without image guidance, and allows adequate facet osteotomy to enable fusion. There are multiple potential advantages of this technique, including: less blood loss, shorter hospital stay, earlier mobilization, and relatively less pain and need for pain medication. The operative time needed to complete this surgery is longer. We feel that a minimally invasive approach, although technically challenging, is a feasible option in patients with adolescent idiopathic scoliosis. Although there are multiple perceived benefits, long term data is needed before it can be recommended for routine use.

Knowledge of abnormal pedicles may enable surgeons to anticipate and plan for difficult screw placement and further decrease risk to the patient.