| dc.description.abstract | Median sternotomy is the most common incision used in cardiac surgery worldwide with more than a million procedures operated annually (Epstein et al, 2011; Go et al, 2014), due to its ease of performance and provision of optimal exposure of the heart (El Ansary et al, 2007c; McGregor et al, 1999; Robicsek et al, 2000; Zeitani et al, 2006; Deb et al, 2013) It remains the standard of care for myocardial revascularization in cardiac surgery, in particular for multi-vessel disease (Cheng & Slaughter, 2013; Deb et al, 2013; Rosenfeldt et al, 2012; Taggart, 2013b). Despite the advantages of a median sternotomy, the incidence of sternal complications has remained relatively unchanged for the last two decades and is reported to be between 1 to 8% worldwide (Balachandran et al, 2016; El-Ansary, 2000b; Ho et al, 2002; ASCTS Data 2013) Sternal complications can range from post-sternotomy pain, skin infections, dehiscence, sternal instability/non-union and mediastinitis (Crabtree et al, 2004; El-Ansary et al, 2008; Cahalin et al, 2011; ASCTS Data 2013). These complications are associated with significant morbidity, and prolonged patient hospitalization which is reported to triple the cost of care (Losanoff et al 2002b; Crabtree et al, 2004; Zeitani et al, 2006; El-Ansary et al, 2008; Baskett et al, 1999; Filsoufi et al, 2009; Joseph et al, 2014; Cahalin et al, 2011; Mekontso et al; 2011; Lazar et al, 2016).
In an attempt to facilitate sternal healing and prevent sternal complications, patients who have undergone cardiac surgery via a median sternotomy are routinely asked to follow sternal precautions post-operatively (Balachandran et al, 2014; Tuyl et al, 2012, Cahalin et al, 2011; Overend et al, 2010). These precautions place restrictions on the use of the upper limbs and trunk immediately following surgery (Balachandran et al, 2014; Tuyl et al, 2012, Cahalin et al, 2011; Overend et al, 2010; Brocki et al., 2010). Sternal precautions are applied worldwide for duration of four weeks to three months following surgery despite a paucity of research to support this practice (Balachandran et al, 2014; Tuyl et al, 2012, Cahalin et al, 2011; Overend et al, 2010; Brocki et al, 2010). Recent research has reported that minimal sternal motion takes place between the sternal edges as measured by ultrasound during upper limb and trunk activity (Balachandran, 2015; Balachandran et al, 2017). Furthermore, such sternal micro-motion may constitute part of the normative path to bone healing (Balachandran et al, 2014; Balachandran et al, 2017; Cahalin et al, 2011). Sternal precautions in their current form may be overly restrictive thus delaying recovery and a return to community role healing (Balachandran et al, 2014; Balachandran et al, 2017; Cahalin et al, 2011).
This thesis examined (1) whether change to sternal precautions impact upon function and sternal pain following cardiac surgery via a median sternotomy A randomized controlled trial (RCT) was conducted to assess how changes to sternal precautions impact upon function, and sternal pain following cardiac surgery via a median sternotomy Nested within the RCT, a repeated cohort studies were conducted to assess the clinimetric properties of selected physical function tools ie The Short Physical Performance Battery (SPPB) and The Functional Disability Questionnaire (FDQ) used in the cardiac surgery via a median sternotomy The results provide new clinimetric information on outcome measures targeting the cardiac population and inform the post-operative clinical management and rehabilitation after cardiac surgery.
This thesis is composed of four studies, where each study is focused on specific parameters that are essential in obtaining comprehensive data and results.
In the first study, a protocol for randomised controlled trial was designed to investigate whether changes to sternal precautions impact upon function following cardiac surgery via a median sternotomy The rationale for developing this study protocol was that the routine implementation of sternal precautions worldwide practice following a median sternotomy may delay recovery and be overly restrictive This study is the first randomized controlled trial using an intervention group to modify sternal precautions, and study its effectiveness in improving physical function in this population The intervention was built on foundational evidence that evaluated the effects of upper limb exercise by investigating the effects of modifying sternal precautions to include the safe use of upper limbs and trunk, and assess their impact on patients’ physical following cardiac surgery via median sternotomy in order to optimize functional recovery in this patient population.
The second study nested within the study 1 was conducted to determine the clinical applicability of the Short Physical Performance Battery (SPPB), when used in patients post cardiac surgery This study evaluated the MCID of the SPPB, an outcome measure that has been validated in older patients who were classified as cardiovascular stable Importantly this study is the first to determine the MCID of the SPPB for an adult cardiac surgery population The results of this study should be considered preliminary evidence on the application of the SPPB to evaluate treatment effectiveness by detecting a true improvement An increase or decrease in performance greater than the MCID indicates a high likelihood of a meaningful change These measures can be used to document real improvements in physical function through the course of cardiac rehabilitation Therefore, it is recommended that an MCID reference value above one point of the SPPB scores could serve as an explicit therapeutic goal for rehabilitation intervention and monitoring functional progress following cardiac surgery.
The third study incorporated a novel outcome assessment of upper limb and trunk function specific to cardiac surgery developed by a team of researchers within the Department of Physiotherapy at the Melbourne University This was a comprehensive clinometric analysis of the FDQ including: the statistical feasibility of a shortened FDQ (FDQ-s), validity, reliability, responsiveness, interpretability, and feasibility The findings of this study established that the FDQ-s has strong clinimetric properties with moderate to excellent results on all domains As such, it is recommended that the FDQ-s be adopted as an outcome measure of physical recovery after cardiac surgery within the acute hospital setting, and in the community to plot the trajectory of recovery overtime Further, the FDQ-s can be utilized in research trials evaluating function and in the clinical setting by health professionals to inform and guide management after cardiac surgery The FDQ-s may be a useful tool in understanding the benefits of physical limitations after cardiac surgery, and thus lead to more finely tailored and individualized health care interventions.
The final study in this thesis presents the results from a RCT, the Sternal Management Accelerated Recovery Trial (SMART) that investigated a standard restrictive versus a program of modified sternal precautions following cardiac surgery via a median sternotomy The findings of this study suggest that a program of modified (less-restrictive) sternal precautions for patients following cardiac surgery did not improve physical recovery, pain or enhance health related quality of life (HRQoL) compared to usual care With no adverse event, the results of this RCT suggest that a precautionary approach that is less restrictive with a progression of activity will likely facilitate optimal functional recovery after a median sternotomy Importantly, this result adds further evidence that strict adherence to SP may not be warranted for all patients as it reinforces kinesiophobia which may potentially impact on patient participation exercise and in cardiac rehabilitation It is recommended that a program of sternal precautions based on individual clinical characteristics and risk profile rather than a generic and routine set of SP may result in optimal recovery Findings in this field of research will be of great importance to enhance, develop and evolve SP to provide patients with the optimal care for post-operative physical and sternal pain management.
The findings of this thesis supported the need in the development, and implementation of clinical and regulatory guidelines to improve patient and community safety; quality of life and standards of care for individuals following cardiac surgery The thesis addresses the paucity of research and the inconsistent recommendations with respect to sternal precautions and associated restrictions to upper limb and trunk provided to the large number of individuals having open-heart surgery nationwide In particular, this research will inform guidelines for the commencement of upper limb activities in Cardiac Rehabilitation (CR) and standards for sternal precautions following cardiac surgery
This thesis further addressed the gaps in the literature pertaining to the outcome measures used following cardiac surgery performed via sternotomy The results of the two outcome measure studies recommended that the SPPB and FDQ be used as measure tools for outcome assessment in research studies, to assess the impact of post-operative rehabilitation management, and better elucidate the process of recovery after cardiac surgery in the acute clinical setting.
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