Purpose To investigate whether the World Health Organization Safety Surgical Checklist (SSC) is an effective tool to reduce complications in spinal surgery. Methods We retrospectively evaluated the clinical and radiological charts prospectively collected from patients who underwent a spinal surgery procedure from January 2010 to December 2012. The aim of this study was to compare the incidence of complications between two periods, from January to December 2010 (without checklist) and from January 2011 and December 2012 (with checklist), in order to assess the checklist's effectiveness. Results The sample size was 917 patients with an average of 30-month follow-up. The mean age was 52.88 years. The majority of procedures were performed for oncological diseases (54.4%) and degenerative diseases (39.8%). In total, 159 complications were detected (17.3%). The overall incidence of complications for trauma, infectious pathology, oncology, and degenerative disease was 22.2%, 19.2%, 18.4%, and 15.3%, respectively. No correlation was observed between the type of pathology and the complication incidence. We observed a reduction in the overall incidence of complications following the introduction of the SSC: In 2010 without checklist, the incidence of complications was 24.2%, while in 2011 and 2012, following the checklist introduction, the incidence of complications was 16.7% and 11.7%, respectively (mean 14.2%). Conclusions The SSC seems to be an effective tool to reduce complications in spinal surgery. We propose to extend the use of checklist system also to the preoperative and postoperative phases in order to further reduce the incidence of complications.

Aims There is evidence that prior lumbar fusion increases the risk of dislocation and revision after total hip arthroplasty (THA). The relationship between prior lumbar fusion and the effect of femoral head diameter on THA dislocation has not been investigated. We examined the relationship between prior lumbar fusion or discectomy and the risk of dislocation or revision after THA. We also examined the effect of femoral head component diameter on the risk of dislocation or revision. Methods Data used in this study were compiled from several Finnish national health registers, including the Finnish Arthroplasty Register (FAR) which was the primary source for prosthesis-related data. Other registers used in this study included the Finnish Health Care Register (HILMO), the Social Insurance Institutions (SII) registers, and Statistics Finland. The study was conducted as a prospective retrospective cohort study. Cox proportional hazards regression and Kaplan-Meier survival analysis were used for analysis. Results Prior lumbar fusion surgery was associated with increased risk of prosthetic dislocation (hazard ratio (HR) = 2.393, p < 0.001) and revision (HR = 1.528, p < 0.001). Head components larger than 28 mm were associated with lower dislocation rates compared to the 28 mm head (32 mm: HR = 0.712, p < 0.001; 36 mm: HR = 0.700, p < 0.001; 38 mm: HR = 0.808, p < 0.140; and 40 mm: HR = 0.421, p < 0.001). Heads of 38 mm (HR = 1.288, p < 0.001) and 40 mm (HR = 1.367, p < 0.001) had increased risk of revision compared to the 28 mm head. Conclusion Lumbar fusion surgery was associated with higher rate of hip prosthesis dislocation and higher risk of revision surgery. Femoral head component of 32 mm (or larger) associates with lower risk of dislocation in patients with previous lumbar fusion. Cite this article: Bone Joint J 2020;102-B(8):1003–1009.

The semi-empirical method is employed in modelling a commercially used counter balance valve for hydraulic crane circuit simulation applications. By means of the method the analytical model of the valve is brought into a form in which the number of the parameters whose values can be determined from the measured characteristic curves is small.The particular problems apparent when modelling the counter balance valves such as description of high seal friction and complicated flow force characteristic are solved by using pure empirical functions.

Introduction The surgical treatment of complex spinal deformity and vertebral oncological diseases is becoming more common. The aim of this study was to prospectively record all the major complications observed in the perioperative and postoperative period for surgeries performed at our Division of Spine Surgery in the 2010 to 2012 period, correlating this score with different parameters to determine possible risk factors. Material and Methods A total of 285 surgeries were registered in 2010, 324 in 2011, and 308 in 2012. All the complications observed during the procedure and the follow-up period were recorded and classified according to the type (mechanical complications, neurological complications, infection, hematoma, cerebrospinal fluid fistula, systemic complications, and death related to the surgery). Results In 2010, on 285 surgeries 47 patients (16.5%) had 69 complications (24.2%): 25.7% for the treatment of oncological diseases, 23% for the treatment of degenerative diseases, 27% for the treatment of pathologies of traumatic origin, and 11% for the treatment of spondylodiscitis (infectious diseases). In 2011, on 324 surgeries 35 patients (10.8%) had 54 complications (16.7%): 16.3% for the treatment of oncological diseases, 16.3% for the treatment of degenerative diseases, 20% for the treatment of pathologies of traumatic origin, 28.6% for the treatment of spondylodiscitis. In 2012, on 308 surgeries, 25 patients (8.1%) had 36 complications (11.7%): 14.4% for the treatment of oncological diseases, 7.2% for the treatment of degenerative diseases, 16.7% for the treatment of pathologies of traumatic origin, and 20% for the treatment of spondylodiscitis. Conclusion On 917 spinal surgeries performed from January 2010 to December 2012, 159 complications (17.3%) were recorded, with a prevalence of mechanical complications and infections. The correlation of these complications with different parameters, such as age, sex, presence of comorbidities, previous spine surgery, type of surgery, will be analyzed to detect potential risk factors to be taken into consideration in the decision-making process for complex spinal surgery.