ABSTRACT
INTRODUCTION: The aim of this study was to assess the safety of our spinal surgery pathways for patients over the age of 70 years during the COVID-19 pandemic, to guide future management. METHODS: A retrospective, single-centre, observational cohort study of all patients over 70 years of age undergoing spinal surgery between June 1 to September 30, 2020, was performed. All patients were stratified by the British Orthopaedic Association (BOA) COVID-19 Patient Risk Assessment Tool. RESULTS: A total of 64 operations on 59 patients were performed. The BOA risk assessment placed 67.8% of patients (n=40) in the high or very high-risk category. A total of 60% of patients (n=36) were over 75 years old. All patients had at least one other comorbidity. Following our green, amber, and red pathways, we had no cases of post-operative COVID-19 on an average follow-up of 71 days. CONCLUSION: Our study illustrates safe pathways for spinal surgery on patients over 70 years old during the first wave of COVID-19. Risk assessment tools should be used with caution, as age over 65 years was immediately medium-risk. This study would be a useful guide in the management of all elderly patients requiring surgery in the face of further COVID-19 variants or a similar pandemic.
ABSTRACT
BACKGROUND: Bone cement is an effective means of supporting implants, but reaches high temperatures while undergoing polymerisation. Bone has been shown to be sensitive to thermal injury with osteonecrosis reported after one minute at 47°C. Necrosis during cementing may lead to loosening of the prosthesis. Some surgeons fill the joint cavity with cool irrigation fluid to provide a heatsink during cementing, but this has not been supported by research. This paper assesses a simple technique to investigate the efficacy of this method. FINDINGS: We used a model acetabulum in a bovine humerus to allow measurement of bone temperatures in cementing. Models were prepared with a 50 mm diameter acetabulum and three temperature probe holes; two as close as possible to the acetabular margin at half the depth of the acetabulum and at the full depth of the acetabulum, and one 10 mm from the acetabular rim. Four warmed models were cemented with Palacos RG using a standard mixing system and a 10 mm polyethylene disc to represent an acetabular component. Two of the acetabular models were filled with room temperature water to provide a heatsink. An electronic probe measured temperature at 5 second intervals from the moment of cementing.In the models with no heatsink, peak temperature was 40.3°C. The mean temperature rise was 10.9°C. In the models with a heatsink, there was an average fall in the bone temperature during cementing of 4.4°C. CONCLUSIONS: These results suggest that using a heatsink while cementing prostheses may reduce the peak bone temperature. This study demonstrates a simple, repeatable technique which may be useful for larger trials.
