Spondylolisthesis is the displacement of one spinal vertebra compared to another. While some medical dictionaries define spondylolisthesis specifically as the forward or anterior displacement of a vertebra over the vertebra inferior to it (or the sacrum), it is often defined in medical textbooks as displacement in any direction. Spondylolisthesis is graded based upon the degree of slippage of one vertebral body relative to the subsequent adjacent vertebral body. Spondylolisthesis is classified as one of the six major etiologies: degenerative, traumatic, dysplastic, isthmic, pathologic, or post-surgical. Spondylolisthesis most commonly occurs in the lumbar spine, primarily at the L5-S1 level with the L5 vertebral body anteriorly translating over the S1 vertebral body. Types
Olisthesis (synonym olisthy) is a term that more explicitly denotes displacement in any direction. Forward or anterior displacement can specifically be called anterolisthesis. Anterolisthesis commonly involves the fifth lumbar vertebra. Backward displacement is called retrolisthesis. Lateral displacement is called lateral listhesis or laterolisthesis.A hangmans fracture is a specific type of spondylolisthesis where the second cervical vertebra (C2) is displaced anteriorly relative to the C3 vertebra due to fractures of the C2 vertebras pedicles. Anterolisthesis
Classification
Anterolisthesis can be categorized by cause, location and severity. By causes
Degenerative anterolisthesis (a.k.a. type 3) is a disease of the older adult that develops as a result of facet arthritis and joint remodeling. Joint arthritis, and ligamentum flavum weakness, may result in slippage of a vertebra. Degenerative forms are more likely to occur in women, persons older than fifty, and African Americans.
Etravirine (ETR, brand name Intelence, formerly known as TMC125) is a drug used for the treatment of HIV. Etravirine is a non-nucleoside reverse transcriptase inhibitor (NNRTI). Unlike the currently available agents in the class, resistance to other NNRTIs does not seem to confer resistance to etravirine. Etravirine is marketed by Janssen, a subsidiary of Johnson & Johnson. In January 2008, the Food and Drug Administration approved its use for patients with established resistance to other drugs, making it the 30th anti-HIV drug approved in the United States and the first to be approved in 2008. It was also approved for use in Canada on April 1, 2008.Etravirine is licensed in the United States, Canada, Israel, Russia, Australia and the European Union, and is under regulatory review in Switzerland. Indications and dosage
Etravirine, in combination with other anti-retrovirals, is indicated for the treatment of human immunodeficiency virus type 1 (HIV-1) infection in antiretroviral treatment-experienced adult patients, who have evidence of viral replication and HIV-1 strains resistant to a non-nucleoside reverse transcriptase inhibitor (NNRTI) and other antiretroviral agents. The recommended dose of etravirine is 200 mg (2 x 100 mg tablets, or 1 x 200 mg tablet as of 03/18/2011) taken twice daily following a meal. The type of food does not affect the exposure to etravirine. Contraindication
Each 100 mg etravirine tablet contains 160 mg of lactose. Patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicine.