Pedicle screw fixation is technically demanding and associated with high complication rates. The aim of this study was to identify and quantify the pedicle screw-related complications in 105 consecutive operations. We retrospectively analysed 105 consecutive primary operations. We found complications of varying severity in 54% of the patients. Deep infections were found in 4.7%, all successfully cured by debridement and antibiotics. There were no permanent neurological complications related to the screws. One serious neurological sequela, a T10 paraplegia, was unrelated to screw placement between L3 and S1. Screw misplacement was found in 6.5% of the screws. Screw breakage occurred in 12.4% of the patients, inevitably leading to loss of correction. Reduced spondylolisthesis L5-S1 without anterior support was found to be especially prone to screw breakage. The study confirmed that pedicle screw placement is a technically demanding procedure with a high complication rate. Fortunately, most complications are not severe. Infections can be dealt with by thorough debridement and parenteral antibiotics. Neurological sequelae can be minimised by careful tactile technique. To avoid screw breakage and subsequent loss of correction, anterior support should be provided, through either posterior or anterior lumbar interbody fusion (PLIF or ALIF) techniques, in reduced spondylolisthesis L5-S1.