Cerebrospinal Fluid Drainage (CSFD) in Acute Spinal Cord Injury
Acute spinal cord injury (SCI) affects 10,000-14,000 persons per year in the United States (Burke, Linden et al. 2001). There are 150,000-300,000 persons living with significant disabilities from SCI at any given time (Bernhard, Gries et al. 2005).
The average age of incident cases of SCI is 47 years and about 78% of the cases are males (DeVivo and Chen 2011). Estimates of the lifetime costs to care for someone with a SCI range from $325,000 to $1.35 million and the yearly cost to society reaches $8 billion (Sekhon and Fehlings 2001). With better long term care technologies, these costs are expected to continue to rise.
Although there have been significant advances in accessibility for people with disabilities, the goal of medical science is to overcome the physiological barriers imposed by the injury itself and allow these individuals to regain their pre-injury level of neurological function (Rowland, Hawryluk et al. 2008). The injury to the spinal cord occurs in two phases. The first phase is the primary physical damage due to the impact energy of the compressive nature of the injury. The damage can be very complex with shearing of the axons, destruction of the cell bodies and disruption of the microvasculature at the site of injury.
The secondary phase of the injury begins soon after the primary injury has occurred and can be influenced by many factors such as hypoxia, hypotension, and the extent of the primary injury. Spinal cord ischemia post-injury causes a significant increase in cell death and more significant neurological disability. Limiting tissue hypoperfusion post-injury can decrease the amount of cell death and axonal damage.
Lumbar cerebrospinal fluid drainage (CSFD) together with increased mean arterial blood pressure (MAP) in the immediate post-injury period can reduce spinal cord tissue hypoperfusion. By reducing spinal cord hypoperfusion through elevation of MAP, less cell death and axonal damage will occur, leading to an improvement in neurological function.
The feasibility of CSFD as a means for reducing the intrathecal pressure (ITP) in patients with acute SCI has been demonstrated in a small randomized controlled trial by Kwon et al (Kwon, Curt et al. 2009). The limitations were a small sample size, broad inclusion criteria, lack of statistical power calculation and restricted drainage regimen (maximum 10 mL per hour).