## 3 The Application of Lean Six Sigma to Surgical Pathways
### Rehabilitation  
Surgical rehabilitation, also known as post-operative rehabilitation, is a specialized area of healthcare that focuses on the recovery and rehabilitation of patients who have undergone surgery. Rehabilitation is a dynamic and critical component of any modern healthcare system, associated with improved health outcomes, reduced disability, and improved quality of life [59]. Surgery can have both physical and psychological effects which may influence recovery and clinical outcomes; therefore, a thorough assessment and an individualised approach in the pre-operative period [41; 42] are key to effective post-operative rehabilitation [60]. Rehabilitation involves a multidisciplinary approach that aims to optimize patient outcomes, improve functional recovery, manage pain, and facilitate a safe return to daily activities following surgery [61], an approach for which Lean Six Sigma has proven highly effective [62]. Surgical rehabilitation typically involves a large team of healthcare professionals, including surgeons, physiotherapists, occupational therapists, nurses, and other specialized healthcare providers, who work together to provide comprehensive care for patients recovering from surgery [63]. Post-operative rehabilitation focuses on restoring physical abilities and relearning skills. It also involves patients learning to cope and adapt to the changes they experience after surgery [64], encouraging them to play an active role in their rehabilitation by involving them, where appropriate, in goal setting to maximise their recovery potential and reduce any secondary problems as a result of the surgery. The goals of surgical rehabilitation will naturally vary depending on the type and complexity of the surgery, the patient's individual needs, and the specific requirements of the surgical procedure. The application of Lean Six Sigma methodology in post-operative care and rehabilitation can support the recovery process for patients regardless of the specific surgery, when applied at the following common areas for potential improvement:  
* Restoring function. Surgical rehabilitation aims to help patients regain their pre-surgery level of function or achieve the highest level of functional recovery possible. Lean Six Sigma has proven effective in enhancing processes for therapies including physiotherapy [30; 62], occupational therapy [65], and other modalities to improve mobility, strength, flexibility, coordination, and other functional abilities. * Pain management. Pain is a common issue after surgery, and effective pain management is an important aspect of surgical rehabilitation. Lean Six Sigma has been used to reduce nursing delays in administering medication [66] and to maximize the availability of opioid pain management medications [35] to help patients manage pain during their recovery process. * Wound care. Meticulous wound care protocols are essential for preventing infections and promoting healing after surgery [67]. Surgical rehabilitation may involve monitoring and managing surgical wounds, providing education on wound care, and coordinating with the surgical team to ensure optimal wound healing. Lean Six Sigma has proven effective in reducing the number of patients who get hospital-acquired infection (HAI), resulting in a significant reduction in the patient length of stay [68]. * Patient education. As with preparation for surgery, education plays a critical role in surgical rehabilitation as patients need to understand their surgical procedure, the recovery process, the need for early mobilisation after surgery [69, 62], and how to manage their post-operative care at home. Post-operative patient education is a key component of Lean Six Sigma initiatives that leads to reduced post-operative complications [34, 62]. * Enhanced Recovery Programs. The Enhanced Recovery After Surgery (ERAS) concept, sometimes referred to as 'fast track', 'accelerated,' or 'rapid recovery' surgery, was first introduced in 1997 [70, 71].