Continuous spinal anesthesia.

Continuous spinal anesthesia (CSA) is an underutilized technique in modern anesthesia practice. Compared with other techniques of neuraxial anesthesia, CSA allows incremental dosing of an intrathecal local anesthetic for an indefinite duration, whereas traditional single-shot spinal anesthesia usually involves larger doses, a finite, unpredictable duration, and greater potential for detrimental hemodynamic effects including hypotension, and epidural anesthesia via a catheter may produce lesser motor block and suboptimal anesthesia in sacral nerve root distributions. This review compares CSA with other anesthetic techniques and also describes the history of CSA, its clinical applications, concerns regarding neurotoxicity, and other pharmacologic implications of its use. CSA has seen a waxing and waning of its popularity in clinical practice since its initial description in 1907. After case reports of cauda equina syndrome were reported with the use of spinal microcatheters for CSA, these microcatheters were withdrawn from clinical practice in the United States but continued to be used in Europe with no further neurologic sequelae. Because only large-bore catheters may be used in the United States, CSA is usually reserved for elderly patients out of concern for the risk of postdural puncture headache in younger patients. However, even in younger patients, sometimes the unique clinical benefits and hemodynamic stability involved in CSA outweigh concerns regarding postdural puncture headache. Clinical scenarios in which CSA may be of particular benefit include patients with severe aortic stenosis undergoing lower extremity surgery and obstetric patients with complex heart disease. CSA is an underutilized technique in modern anesthesia practice. Perhaps more accurately termed fractional spinal anesthesia, CSA involves intermittent dosing of local anesthetic solution via an intrathecal catheter. Where traditional spinal anesthesia involves a single injection with a somewhat unpredictable spread and duration of effect, CSA allows titration of the block level to the patient's needs, permits a spinal block of indefinite duration, and can provide greater hemodynamic stability than single-injection spinal anesthesia.