Aims:To determine if sequential application of povidone iodine-alcohol (PVI) followed by chlorhexidine gluconate-alcohol (CHG) would reduce surgical wound contamination to a greater extent than PVI applied twice in spinal surgery patients. Patients and Methods: A single-centre, interventional, two arm, parallel group randomised controlled trial of 407 patients attending hospital for elective spinal surgery was conducted. For 203 patients, pre-surgical skin disinfection was by application of PVI (10% [w/w (1% w/w available iodine)] povidone iodine in 95% industrial denatured alcohol; Videne Alcoholic Tincture) twice and for 204 patients application of PVI once followed by application of CHG (2% [w/v] chlorhexadine gluconate in 70% [v/v] isopropyl alcohol; Chloraprep with tint). The primary outcome measure was post-skindisinfection surgical site contamination determined by aerobic and anaerobicbacterial growth from post-skin disinfection samples. Results: The detection of viable bacteria in any one of the post-skin disinfection samples (culture-positive) was significantly lower in the group treated with both PVI and CHG than in the group treated with PVI alone: 29.1% (59) vs 41.7% (85), P=0.009; relative risk, 0.574; 95% confidence interval, 0.380 to 0.866. Conclusions: Skin antisepsis with sequential application of PVI and CHG more effectively reduces surgical wound contamination than PVI alone.

Computed tomography (CT) of the spine has remained an important tool in the investigation of spinal pathology. This article helps to explain the basics of CT of the lumbar spine to allow the clinician better use of this diagnostic tool.