Retractors available for spinal surgeries through midline posterior approach use separation of blades or pin and blade by hinge joint or pivot with rack gear mechanism. These have been shown to cause ischemia of paraspinal muscles with long term back pain and disability in many studies. We have designed a single blade spinal retractor which can be used in midline posterior approach spinal surgeries, where subperiosteal separation of paraspinal muscles is done. It is made up of 12-15 cm long, 1-1.5 cm wide and 1.5 mm thick stainless steel blade with a 2x5 mm hook (spinal hook) at one end (Laminar end) and V shaped grooves on both the sides 0.5-1 cm from the other end (outer end). Depth of the each groove is 1/3rd of the width of the blade. Last 2 cm of the laminar end (including spinal hook) has a smooth curvature of 5-6 cm circle and the blade is bent about 120� opposite to the curvature at 7-8 cm from the tip of the laminar end. Spinal hook is slipped on the outer edge of the isthmus or lateral mass after superiosteal separation of paraspinal muscles. Grooves on the outer end are used for anchoring it by rubber band or spring to the side rail of the operation theatre table. One retractor is used for one side and one level and can be used for unilateral, bilateral, single level or multiple level surgeries. We conclude that use of Single blade retractor for spinal surgeries through midline posterior approach cause lesser trauma to the paraspinal muscles and are simple to use.
