Frailty and sarcopenia do not predict adverse events in an elderly population undergoing non-complex primary elective surgery for degenerative conditions of the lumbar spine

Publication date: Available online 12 July 2017
Source:The Spine Journal
Author(s): Raphaële Charest-Morin, John Street, Honglin Zhang, Taren Roughead, Tamir Ailon, Michael Boyd, Marcel Dvorak, Brian Kwon, Scott Paquette, Nicolas Dea, Charles G. Fisher, Alana M. Flexman
Background contextSarcopenia measured by normalized total psoas area (NTPA) has been shown to predict mortality and adverse events (AE) in numerous surgical populations. The relationship between sarcopenia and postoperative outcomes after surgery for degenerative spine disease (DSD) has not been investigated.PurposeThis study aimed to determine the relationships between sarcopenia, frailty and postoperative adverse events in the elderly DSD population. Secondary objectives were to describe the distribution and predictors of NTPA and to determine the relationship between sarcopenia, frailty and length of stay, discharge to a facility and in-hospital mortality.Study designThis is an ambispective study from a quaternary care academic centre.Patient sampleA total of 102 patients over 65 years old who underwent elective thoracolumbar surgery for DSD between 2009 and 2013 were included in this study.Outcome measuresThe primary outcome was a composite of perioperative adverse events; secondary outcomes were length of stay, discharge disposition and in-hospital mortality.MethodsTotal psoas area (TPA) at mid-L3 level on pre-operative CT scan adjusted for height (NTPA) defined sarcopenia. The modified Frailty Index (mFI) of 11 clinical variables defined frailty. The distribution and predictors of sarcopenia (NTPA) were determined. The association of NTPA with adverse events, length of stay, discharge disposition to care facility and mortality was analyzed, including adjusting for known and suspected confounders using multivariate regression.ResultsMedian Spine Surgical Invasiveness Index was 8 (IQR 2-10) Mean NTPA was 674mm²/m² (293.21- 1636.25). Using the mFI, 20.6% were pre-frail and 19.6% were frail. Inter- and intra-observer reliability for determining NTPA were near perfect with Kappa 0.95-0.97 and 0.94-1.00 respectively. NTPA was independently associated with patient sex and body mass index (BMI) but not frailty (mFI). Age, BMI, mFI, and ASA were not associated with incidence of postoperative adverse events (AE). NTPA did not predict the occurrence of AE (OR 1.06 per 100 mm²/ m², 95% CI 0.91 to 1.23, p=0.45). Similarly, NTPA was not predictive of length of stay (rho = -0.04, p= 0.67), discharge home (OR 0.95 (95% CI 0.76 to 1.20) per 100 mm²/ m², p=0.70) or death (OR 1.12 (95% CI 0.83 to 1.53) per 100 mm²/ m², p=0.47). In contrast, increasing mFI was associated with increased risk of mortality (OR 3.12 (95% CI 1.21 to 8.03) per 0.1 increase in frailty score, p=0.006).ConclusionsIn contrast to other surgical groups, sarcopenia (NTPA) or frailty (mFI) did not predict acute care complications in a selected population of elderly patients undergoing simple lumbar spine surgery for DSD. While NTPA can be reliably measured in this population, it may be an inappropriate surrogate for sarcopenia given its anatomical relationship to spinal function.



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