According to a study published in The Bone & Joint Journal, the presence of sleep apnoea independently increases the risk of perioperative complications in patients undergoing posterior lumbar fusion. Therefore, patients with sleep apnoea who undergo this type of surgery post a significant challenge to clinicians.
Study authors O Stundner (Paracelsus Medical University, Department of Anaesthesiology, Perioperative Medicine and Intensive Care Medicine, Salzburg, Austria) and others write that sleep apnoea is recognised as a risk factor for complications following posterior lumbar surgery. However, they add that little is known about the prevalence sleep apnoea among patients undergoing spinal surgery and there is little data for the impact of the condition on patients undergoing spinal fusion. The aim of Stundner et al’s study, therefore, was to provide further information on these factors and hypothesised that “sleep apnoea represents an independent risk factor for an adverse outcome after posterior lumbar fusion.”
The authors reviewed medical records (dated from 2006 to 2010) from 400 acute care hospitals in the USA, identifying 84,655 patients who had undergone posterior lumbar fusion. Of these patients, 6,163 had a diagnosis of sleep apnoea; patients with sleep apnoea had a higher median age, were more frequently female, had a higher Deyo comorbidity burden, and had a higher prevalence of comorbidities compared with patients without sleep apnoea. Furthermore, significantly more patients with sleep apnoea were classified as being obese—35.84% of 6,163 vs. 11.85% of 78.492 patients with sleep apnoea (p<0.0001).
Stunder et al report that, according to multivariate analysis, sleep apnoea was an independent risk factor for the development of major complications, need for mechanical ventilation, need for perioperative blood product transfusion, and need for intensive care. They add that the condition was also associated with “prolonged length and increased cost [of care]”. The combination of a comorbid condition (eg. diabetes) and sleep apnoea further increased the risk of major complications, with the authors noting: “Patients suffering from a combination of sleep apnoea and one of these conditions are almost three times more likely to have major perioperative complications than those who do not have these conditions.”
The authors propose that “early identification and triage” of patients with sleep apnoea might “facilitate the appropriate stratification of risk.” They add: “The subsequent introduction or optimisation of preventative treatment measures, including continuous positive airway pressure (CPAP) ventilation, continuous pulse oximetry, extended stay in the recovery room, and the use of regional anaesthesia might lead to improved outcomes in these patients.”
Senior author Stavros G Memtsoudis (The Hospital for Special Surgery, New York, USA; where the study was performed) told Spinal News International: “An important point to consider is that estimates suggest that up to one in four surgical patients suffers from sleep apnoea, but that more than 80% of those are undiagnosed at the time of presentation. This fact poses the additional problem of dealing with untreated sleep apnoea, which may be associated with even higher risk of preoperative complications than that reported in our study (which deals with mostly diagnosed cases of the disease). With the availability of simple screening tools for sleep apnoea, such as the STOP BANG questionnaire, surgeons can easily identify patients at risk for sleep apnoea and—similar to what has been done for cardiac patients for many years—in severe cases refer patients for work up and treatment prior to surgery and devise an individualised perioperative plan. However more research is needed in this field to quantify the benefits of such preoperative interventions.”