Effect of Instrumented Spine Surgery on Length of Stay.

INTRODUCTION: Total joint arthroplasty studies have identified that surgeries that take place later in the week have a longer length of stay compared with those earlier in the week. This has not been demonstrated in studies focused on anterior cervical diskectomy and fusions or minimally invasive lumbar laminectomies. All-inclusive instrumented spine surgeries, however, have not been analyzed. The purpose of this study was to determine whether day of surgery affects length of stay and whether there are predictive patient characteristics that affect length of stay in instrumented spine surgery. METHODS: All instrumented spine surgeries in 2019 at a single academic tertiary center were retrospectively reviewed. Patients were categorized for surgical day and discharge disposition to home or a rehabilitation facility. Differences by patient characteristics in length of stay and discharge disposition were compared using Kruskal-Wallis and chi square tests along with multiple comparisons. RESULTS: Seven hundred six patients were included in the analysis. Excluding Saturday, there were no differences in length of stay based on the day of surgery. Age older than 75 years, female, American Society of Anesthesiology (ASA) classification of 3 or 4, and an increased Charlson Comorbidity Index were all associated with a notable increase in length of stay. While most of the patients were discharged home, discharge to a rehabilitation facility stayed, on average, 4.7 days longer (6.8 days compared with 2.1 days, on average) and were associated with an age older than 66 years old, an ASA classification of 3 or 4, and a Charlson Comorbidity Index of 1 to 3. CONCLUSIONS: Day of surgery does not affect length of stay in instrumented spine surgeries. Discharge to a rehabilitation facility, however, did increase the length of stay as did age older than 75 years, higher ASA classification, and increased Charlson Comorbidity Index classification.

Increasing the elution of vancomycin from high-dose antibiotic-loaded bone cement: a novel preparation technique.

BACKGROUND: Antibiotic bone cement is commonly used in staged revision arthroplasty as well as the treatment of open fractures. Multiple factors affect antibiotic elution from bone cement. This study was performed to investigate the effect of two variables, the quantity of liquid monomer and the timing of antibiotic addition, on the ultimate elution of antibiotic from bone cement. METHODS: Vancomycin-loaded Simplex P and SmartSet MV bone cement was prepared with three different methods: a common surgical technique, a mixing technique that doubled the amount of liquid monomer, and a novel technique that delayed antibiotic addition until after thirty seconds of polymerization. Cylinders of a standardized size were created from each preparation. The elution profiles of five cylinders from each preparation were measured over six weeks with use of high-performance liquid chromatography. Cylinders were tested in compression to quantify strength. RESULTS: Delayed antibiotic addition resulted in significantly greater cumulative elution over six weeks (p < 0.0001), with minimal reduction in strength, compared with the other groups. Doubling the liquid monomer significantly reduced cumulative elution over six weeks compared with either of the other techniques (p < 0.0001). Vancomycin elution from Simplex P was 52%greater and vancomycin elution from SmartSet MV was 25% greater in the delayed-antibiotic-addition groups than it was in the corresponding standard surgical technique groups. The majority of the antibiotic was released over the first week in all groups. : High-dose-antibiotic bone cement prepared with delayed antibiotic addition increased vancomycin elution compared with the standard surgical preparation. Incorporating additional liquid monomer decreased vancomycin elution from high-dose-antibiotic cement. We recommend preparing high-dose-antibiotic bone cement with the delayed-antibiotic addition technique and not incorporating additional liquid monomer. CLINICAL RELEVANCE: Both the relative volume of liquid monomer and the timing of antibiotic addition have substantial effects on the elution of antibiotic from bone cement.