What Is Standard Work?

Following the Allied victory in World War II, Japanese industrialists began studying the American manufacturing processes that enabled the USA to achieve previously unheard of productivity and efficiency in manufacturing (some US plants boasted they were building “a bomber an hour” during the height of the war). The founders of Toyota, for example, combined certain aspects of the Ford system with their own theories on continual process improvement, minimization of waste, and work standardization. The result was the development of the Toyota Production System (TPS) and many of the founding principles of what we refer to today as “lean methodology.” With these principles in practice, Japanese manufacturing was revolutionized into a dominant industrial force of the twentieth century [1, 2].

The TPS comprises a management philosophy centered on core principles of waste minimization and iterative improvements in work processes. A central tenet of the TPS is the development of standard work processes. The concept of standard work was developed by Japanese engineer Taiichi Ohno as a means of achieving incremental improvement (kaizen) in any work process. The concept of kaizen is best summarized by Taiichi Ohno himself, who said, “Without standards, there can be no improvement.” In other words, when work is non-standardized, unpredictable, and highly variable over time, it is impossible to know which components of a work process are adding value and which are adding waste. By establishing a consistent work process with known outcomes (the “standard” work), one creates what is effectively a control group against which future iterative changes to the work process can be compared. Any changes that result in better outcomes are adopted as part of the new standard work process, and any changes that result in worse outcomes are discarded from the process as waste. Improvement in a work process can therefore only be made after establishing a standard work process and identifying the correct process and quality metrics (the outcomes) to measure [2–7].

To standardize a work process, that process must first be deconstructed into discrete steps, and each step detailed according to (1) the person conducting the work, (2) the task itself, and (3) the check process to ensure the work was done sufficiently. By deconstructing work in this fashion, one is able to both establish standards for work performance and identify problems in the work process that prevent achievement of the standard. After a standard is established, incremental improvements in each step of the work process are made in order to improve the entire process. The people responsible for carrying out a work process are furthermore empowered to identify waste in the process or areas of potential improvement and therefore become an essential part of the iterative improvement process [2, 5–7].

The Toyota Production System and Its Application in Healthcare

The success of the TPS in automotive manufacturing has inspired its use in other industries such as diverse manufacturing industries, food service, air travel, retail, and healthcare. Although modifications to the TPS methodology are required when applied to human services industries, the core principles of standard work, continual process improvement, and personnel empowerment remain unchanged. Companies such as Southwest Airlines, Walmart, and Taco Bell have made tremendous gains in productivity and customer satisfaction after employing lean methodologies. These gains have inspired many in healthcare to adopt these same methods [8–20].

In 2002, the Virginia Mason Medical Center became one of the first healthcare institutions to employ lean methods in a hospital-wide attempt to improve the quality of delivered patient care [2]. The impact at Virginia Mason on certain standard quality metrics was astounding: within 2 years of implementing lean methodologies, incidences of ventilator-associated pneumonia at Virginia Mason decreased from 34 cases and 5 deaths annually to 4 cases and 1 death. Annual cost saving to the hospital from this reduction alone was reported to be $500,000 [2, 20–23]. Around the same time, large hospital systems in Pennsylvania and Wisconsin began employing lean methodologies with similarly substantive improvements reported over the following years. The Pittsburgh Regional Health Initiative, for example, achieved a 90% reduction in central line infections within the first year of implementing lean methods to their quality control efforts. ThedaCare in Wisconsin reported $3.3 million in overall institutional savings after implementing their own lean program targeted at identifying and eliminating waste [24].

These early successes in implementing lean methodologies in healthcare settings inspired widespread adoption of lean practices over the past decade throughout nearly every type of healthcare facility and practice setting, from trauma to ambulatory care centers, from academic to private hospital systems, and in fields from family medicine to subspecialty surgery. In some of these examples, successful implementation of TPS principles relied heavily on an institution-wide adoption of certain cultural changes, including empowerment of individuals and a willingness and commitment to make iterative changes in order to achieve continuous process improvement.

What Is the Virginia Mason Production System? How Does This System Root Out Variability?

The early success of lean methodologies applied in the Virginia Mason Medical Center inspired the development of the Virginia Mason Production System (VMPS), an adaptation of the TPS on a medical center-wide scale [21]. A keystone principle of the VMPS is the establishment of a healthcare culture in which each person is empowered to examine work processes and implement changes in those processes to achieve continuous improvement. Hospital leadership is responsible for creating and supporting this culture from the top down, as well as providing comprehensive oversight of ongoing work processes, instituted changes, and the results of these changes on process outcomes. By their nature, lean processes are continually evolving; the VMPS has created its own system for systematically monitoring the changes that have been implemented and the effect of these changes on work processes over time. After having been in place for over a decade, the VMPS has achieved annual systematic reductions in cost and medical errors throughout the Virginia Mason Medical Center. As a result, the VMPS principles have been extended into certain high-risk, high-cost specialties such as orthopedic surgery and neurosurgery [22–35].

The ability of the VMPS to achieve continuous improvement in healthcare outcomes is dependent on its ability to root out variability in healthcare work processes. After targeting a value-focused area of potential improvement, the first step in the VMPS is to deconstruct the work processes involved and to define those processes in terms of the task, the person conducting the task, and monitoring of task performance. Once this is accomplished, a task performance standard can be established, and all persons performing that task can be evaluated in respect to the new standard. Variables in task performance that result in above or below standard outcomes can then be identified, changes to the work processes that favor above standard work can be iteratively implemented, and over time the variability in work process performance is eliminated in favor of best practices.

Cultural Aspects of Hierarchy in Medicine and Surgery (the Old Standard Way)

The application of an automotive manufacturing management philosophy to a field as complex as healthcare is fraught with challenges. First, healthcare does not function like most business entities in which there is a single hierarchy of decision-making authority and a single CEO ultimately responsible for the collective success or failure of the company. In healthcare, every physician involved in the care of a patient has traditionally functioned essentially as their own CEO, ultimately responsible for the success or failure of their own patient management decisions, while each patient’s eventual outcome is often dependent on the collective impact of multiple physicians’ and team member’s input. The notion of standardizing work processes in a system with such diffuse decision-making authority and disparate work processes is daunting. Furthermore, many physicians are wary of systems in which their own decision-making process can be supplanted or changed, as they will ultimately be responsible (and legally liable) for their patients’ outcomes and satisfaction. This is evolving in recent years with the enhanced understanding of the role of teams and physicians as team leaders and team members.

Secondly, the type of work conducted across different healthcare settings varies significantly from easily defined processes (i.e., patient transportation, bed turnover, blood draws) to much more ambiguous processes such as medical decision-making. When applied to unambiguous and easily articulated tasks such as central venous line or endotracheal tube management protocols, lean process methodologies can readily be employed [8–19]. But when applied to more complex tasks that require rapid decision-making based on numerous information streams from sources of variable reliability, the notion of task deconstruction and standardization becomes more difficult. These complex types of work processes can more broadly be defined as “knowledge work.” Knowledge work requires an expert in a given area (i.e., a physician) to collect information from various sources and then synthesize that information to make a decision. The mental work processes that dictate the physician’s decision-making process are often ambiguous and unpredictable and rely heavily on physician experience and tacit knowledge, the “art” of medicine. Some believe that because knowledge work is not repetitive and cannot be unambiguously defined, this type of work is not well-suited for lean methodologies [42].

The impact of these challenges on healthcare quality improvement has been a split in the type of work processes that generally undergo lean process development. Hospital tasks that are largely overseen by nursing and nonphysician staff have a long-track record of success in improving quality metrics after lean practices are implemented. Physicians, on the other hand, have been more skeptical and slower to adopt lean practices as their work processes are more difficult to standardize, and the hierarchy of decision-making authority in which they operate is highly fractionated. Thus, the old standard way of practice continues to prevail at many institutions, individual physicians performing the same tasks using widely disparate work processes and achieving highly variable results. When work is non-standardized, unpredictable, or highly variable in this fashion, it is impossible to establish a standard and therefore difficult to nearly impossible to know how to improve the work and demonstrate enhancements in quality.

Adult Spinal Deformity Surgery as a Case Study (the Need for Change)

The shortcomings of the old, non-standardized way of delivering healthcare are most readily seen in the performance of our highest-risk surgical procedures. Surgical corrections of adult spinal deformities, for example, are among the most dangerous operations in the surgical armamentarium, with reported morbidity rates ranging from 20% to nearly 90% [43–45]. Intraoperative adverse events are reportedly as high as 10% in these procedures and include temporary or permanent neurological deficit, high-volume blood loss, myocardial infarction, stroke, and/or death [22–29]. There are several reports in the literature of patients who lost more than their total preoperative estimated blood volume during a corrective spinal fusion for scoliosis. As the incidence of degenerative spinal deformity has grown with our aging population and the demand for surgical corrections of these deformities has likewise grown, the same phenomenon has continued through the current decade [46–54]. But despite the morbidity of these procedures, many patients report significant improvements in their quality of life following reconstruction of their spinal deformities, even those who suffer the aforementioned complications [55–67]. The onus is therefore on surgeons to develop strategies for minimizing risk for patients in whom surgery is the only feasible treatment option.

Given the high morbidity and mortality of adult scoliosis correction procedures, there is a growing need to develop strategies aimed at reducing the risk of these procedures. The delivery of surgical care to patients with complex spinal deformities requires a large number of steps across complex healthcare systems that must be completed to take a patient from the beginning to the end of the “production line.” These steps broadly include preoperative work, intraoperative work, and postoperative work. Given individual surgeon variability in training, expertise, and personal experience, the amount of variability and potential for error in the overall work processes surrounding complex surgical spine care is staggering. As such, the delivery of surgical treatment for complex spine deformities lends itself very well to standardized work processes.

Lean methodologies offer a number of potential benefits to spinal reconstructive procedures as many aspects of these procedures lend themselves well to work process deconstruction and standardization. For example, some centers have developed custom protocols designed to minimize individual complications, such as blood loss or postoperative vision loss [36–39]. Others have found success implementing even broader lean protocols, with improvements in outcomes and reduced overall complication rates [40, 41].

The Seattle Spine Team Approach (the New Standard Way)

Prior to the application of broad lean process improvement strategies and standard work principles to the care of adult spinal deformity patients at Virginia Mason, the work processes in place around the care of these patients were highly variable and of unpredictable quality. Complication rates for these procedures were over 50% [40]. After the occurrence of two major complications (a debilitating stroke and intraoperative death), the surgical treatment of all spinal deformities was halted. In car manufacturing, the TPS calls for a production line to be stopped when someone identifies a situation leading to production of a poor-quality vehicle. This same “stop the line” strategy was implemented at Virginia Mason after it became clear that the “production line” for surgical reconstruction of spinal deformities was producing bad outcomes. With the production line stopped, physician stakeholders and hospital personnel were able to conduct root cause analyses to identify numerous areas for potential systems improvement. The end result was a radical reconstruction of the entire work process, an event known in TPS terminology as kaikaku.

The Seattle Spine Team Approach (SSTA) was the standard work process that resulted from this kaikaku approach and is just one example of the broad and systematic application of lean principles to the performance of adult reconstructive spine surgery. Most importantly, the SSTA represents a case study in how lean methodologies can successfully be applied to complex surgical procedures. The first challenge in implementing the SSTA was to define value in scoliosis correction procedures. Although this step may seem intuitive, it is imperative that all key service providers involved in these procedures (surgeons, anesthesiologists, physiatrists, internists, pain specialists, nurses, operating room staff, physician assistants) are included so as to bring together a multidisciplinary perspective on the numerous work processes involved and which outcomes are most important to measure. By including all stakeholders, one furthermore empowers those performing the various tasks required during these procedures to implement change; staff empowerment is one of the key principles of lean manufacturing. Key service providers identified by the SSTA team worked together in a rapid process improvement workshop and collectively defined value as delivering the safest and most effective complex spine surgery at the lowest cost [68].

The next step was to deconstruct the various work processes involved in a complex surgical spine procedure into a standardized work process. To do this, a value stream map was created that incorporates preoperative, perioperative, and postoperative care into a single process flow map. This map delineates each of the steps involved in delivering the defined value (safe, effective surgery at the lowest cost). As this process of value streaming is iteratively performed, current state maps are generated in which each area of the work process for conducting a surgical spine correction is studied in detail to identify waste in the process. Each step in the process can be detailed as broadly or specifically as necessary, depending on the focus of a particular improvement effort. Areas that do not immediately relate to the focus of an improvement effort can be depicted very broadly, whereas those that are directly related are detailed very specifically. This granular view of a particular part of the work process then enables further deconstruction of that task in terms of standardized work: who is performing the task, what is the task, and how is task performance evaluated. Areas of potential improvement are thus identified, and the implementation of changes to the process is initiated [68].

It is important to maintain direct communication with the personnel involved in each process that is identified as a focus area of improvement. In the SSTA, the people involved in the identified tasks are interviewed in the setting of a process improvement workshop focused on identifying waste and inefficiencies in the existing work process. After an intervention is agreed upon, a future state map is created to analyze the ideal value stream that is expected to result from the intervention. This future state value stream is similarly deconstructed into its component standard work to ensure the new value stream is performed as intended and that the intended improvements are made and maintained over time [68].

The desired intervention is then implemented in real time by personnel responsible for the new work process. Assessment of outcome parameters begins immediately and is conducted continuously so that managers can monitor the level of improvement over time. Once the future state value stream is achieved, this value stream becomes the new standard against which all future value streams are compared. This process is then repeated in an iterative process of continuous self-evaluation and improvement [68].

After the SSTA was implemented in this fashion, the overall complication rate for complex spine surgery was reduced from 52% to 16%, and this improvement has been sustained for over 5 years of continuous lean process improvement in preoperative screening, intraoperative communication strategies, complication avoidance protocols, and postoperative care pathways [40]. This continuous process of self-evaluation and iterative changes to work processes is felt by the SSTA team to be essential to maintaining and building on this improvement over time.

Potential Pitfalls and Areas for Improvement