Scheduling operating
rooms: achievements,
challenges and pitfalls
Samudra M, Van Riet C, Demeulemeester E, Cardoen
B, Vansteenkiste N, Rademakers F.
KBI_1608
Scheduling operating rooms:
Achievements, challenges and pitfalls
Michael Samudra · Carla Van Riet · Erik Demeulemeester · Brecht
Cardoen · Nancy Vansteenkiste · Frank E. Rademakers
Abstract In hospitals, the operating room (OR)
is a particularly expensive facility and thus effi-
cient scheduling is imperative. This can be greatly
supported by using advanced methods that are
discussed in the academic literature. In order to
help researchers and practitioners to select new
relevant articles, we classify the recent OR plan-
ning and scheduling literature into tables using
patient type, used performance measures, deci-
sions made, OR supporting units, uncertainty, re-
search methodology and testing phase. Addition-
ally, we identify promising practices and trends
and recognize common pitfalls when research-
ing OR scheduling. Our findings indicate, among
others, that it is often unclear whether an arti-
cle mainly targets researchers and thus contributes
advanced methods or targets practitioners and
consequently provides managerial insights. More-
over, many performance measures (e.g., overtime)
are not always used in the correct context. Fur-
thermore, we see that important information that
would allow readers to determine whether the re-
ported research results are relevant to them is of-
ten missing. In order to avoid these pitfalls, we
conclude that researchers need to state whether
they target researchers or practitioners, motivate
the choice of the used performance measures and
mention both setting and method specific assump-
tions.
M. Samudra, C. Van Riet, E. Demeulemeester, B. Cardoen
Faculty of Economics and Business, KU Leuven
E-mail: carla.vanriet@kuleuven.be (
)
B. Cardoen
Vlerick Business School, Faculty of Economics and Busi-
ness, KU Leuven
N. Vansteenkiste, F. Rademakers
University hospital Leuven
Keywords Health care management · Surgery
scheduling · Operating room planning · Review
1 Introduction
Health care has a heavy financial burden for gov-
ernments within the European Union as well as
in the rest of the world. Additionally, while grow-
ing economies and newly emerging technologies
could lead us to believe that supporting our re-
spective national health care systems might get
less expensive over time, data show that this is not
the case.
For example, within the USA, the National
Health Expenditure as a share of the Gross Do-
mestic Product (GDP) was 17.4% in 2013 [54].
On the European continent, even though large dif-
ferences exist across member states, health care
expenditure as a share of the GDP was 8.7% in
2012 [193]. Hospitals are responsible for more
than one third of these expenditures [86].
Within the hospital, considerable attention is
given to operating rooms (ORs) as they represent
a significant segment of hospital costs [120]. Out
of the many aspects of OR management, we focus
our attention on planning and scheduling prob-
lems (the terms planning and scheduling are in this
article used interchangeably).
Given the importance of OR scheduling, it is
not surprising that many research groups from the
operations research community provide solution
approaches to the problems that affect it. Reviews
on this literature are important as they help re-
searchers to select relevant articles for their re-
search setting and serve as a guide for practition-
ers (e.g, hospital manager) to quickly find papers
that can contain useful managerial insights.
2 M. Samudra, C. Van Riet, E. Demeulemeester, B. Cardoen, N. Vansteenkiste, F. Rademakers
Additionally, reviews preferably cover the fol-
lowing two important aspects. First, they help
to identify promising practices and shows recent
trends (i.e., hot topics). Second, they identify com-
mon pitfalls or important aspects to consider when
doing researching in this field. To our knowledge,
there is no recent review on OR planning that con-
siders these latter two aspects.
In order to cover these aspects, we define the
following three research tasks. First, to classify
the recent OR planning and scheduling literature
(Sec. 3.1-3.7) using a simple, but comprehensive
framework. For this task, we build up on the work
carried out by Cardoen et al. [42] and Demeule-
meester et al. [60]. Second, to look for evolutions
over time, common approaches and relations be-
tween the different classification fields (Sec. 3.1-
3.8). Third, to identify the common pitfalls (e.g.,
information that we found missing in some arti-
cles) and to develop guidelines that can help re-
searchers to avoid them (Sec. 4.1-4.3).
The purpose of the remaining sections is to ex-
plain the research method (Sec. 2.1), to position
this paper in the existent group of reviews (Sec.
2.2), to introduce the classification fields (intro-
duction of Sec. 3), to discuss the limitations of this
study (Sec. 4.4) and to describe our main conclu-
sions (Sec. 5).
2 Search Method and Other Reviews
In Sect. 2.1, we introduce the procedure that we
used to identify relevant articles. In Sect. 2.2, we
discuss the structure and scope of reviews written
on similar topics and position our review within
the context of this existing literature.
2.1 Search Method
We searched the databases Pubmed and Web of
Science for relevant articles, which are written
in English and appeared in 2000 or afterwards.
Search phrases included combinations of the fol-
lowing words: operating, surgery, case, room, the-
atre(er), scheduling, planning and sequencing. We
searched in both titles and abstracts and in addi-
tion checked the complete reference list of any
already found article. As we endeavored to con-
duct the search process in an unbiased way, we be-
lieve we have obtained a set of articles that objec-
tively represents the literature on OR planning. At
the end of the search procedure, we identified 216
technically oriented papers. Note that we chose to
Table 1 The graphs showing trends are based on papers in
the third column, while the tables additionally include the
papers in the second column
2000-2003 2004-2014
Journal 24 137
Proceedings 3 42
Other 0 10
Total 27 189
investigate trends only from 2004 onwards as in
the preceding years not enough articles were pub-
lished to get reliable results (Table 1).
We define an article as “technical” if it con-
tains an algorithmic description of a method di-
rectly related to OR scheduling. Some articles
are missing this algorithmic component and in-
stead provide managerial insights. Those articles
are excluded from the classification tables, as not
all classification fields apply to them, but some
of their insights are mentioned in the text. The
quantitative descriptions provided in Sec. 3.1-3.8,
which give insights into the changing trends set by
the research community, are exclusively based on
the technical contributions.
The majority of the included articles are re-
cent publications (Fig. 1). This reflects the trend
that the amount of published technical articles
has been increasing significantly in the recent ten
years.
We do not include topics related to business
process reengineering, the impact of introducing
new technologies, facility design or long-term OR
expansion. Also, articles that deal with appoint-
ment scheduling are excluded from this review.
This is the case as some of the basic assumptions
that apply to appointment scheduling are not valid
for surgery scheduling. For a review on appoint-
ment scheduling, we refer to [48].
2.2 Other Reviews
In the past 60 years, a large body of literature on
OR planning and scheduling has been published.
The literature has been structured and reviewed
by several authors, using a variety of classification
techniques and frameworks. We grouped these re-
views based on their scope and structure (Table 2).
Based on the scope of the literature review, we
distinguish between three levels. The first level
purely focuses on the OR department (including
the post-anesthesia care unit (PACU) and the in-
tensive care unit (ICU)). The second level targets
Scheduling operating rooms: Achievements, challenges and pitfalls 3
Number of
published
articles
0
33
2004 20142009
Fig. 1 The number of published technical articles in OR
scheduling has been growing over the last decade
the OR together with other areas that can be of in-
terest in a hospital such as bed planning [26] or
patient flow planning. The third level covers OR
management in the broader context of patient care
and therefore often includes different care services
[128].
In some of the literature reviews articles are
classified based on the three hierarchical decision
levels: strategic (long-term), tactical (medium-
term) and operational (short-term). The strategic
decision level involves decisions that affect both
the number and the type of performed surgeries.
The tactical level usually involves the construction
of a cyclic schedule, which assigns time blocks to
surgeons or surgeon groups. The final, operational
level deals mostly with daily staffing and surgery
scheduling decisions. Guerriero and Guido [105]
also discuss papers that include a mix of the three
levels. Similarly, Vissers et al. [262] propose a
hierarchical framework for production control in
healthcare. They distinguish between five levels
and discuss for each level, amongst others, the
type of decisions, the time horizon and the in-
volved decision makers. With respect to the op-
erational level, a further distinction can be made
between off-line (i.e., before schedule execution)
and on-line (i.e., during schedule execution) ap-
proaches [112].
In other literature reviews custom categories
are used (Table 2). As such, Brailsford and Vis-
sers [36] use the product life cycle stages to re-
view 35 years of papers presented at the ORAHS
conference. Moreover, Erdogan and Denton [82]
review the literature according to the applied so-
lution approach. Przasnyski [210] structures the
literature based on general areas of concern, such
as cost containment. Other reviews structure the
literature on the basis of managerial or functional
levels [207] and problem characteristics, e.g., the
type of the arrival process [110].
Most literature reviews are not only reference
points to articles, but also point out topics for fu-
ture research. Guerriero and Guido [105] conclude
that the three hierarchical levels are rarely stud-
ied together and argue that the tactical level has
received increased attention in the last ten years.
In contrast, Hans and Vanberkel [112] argue that
future research should focus more on the tactical
level.
Also, May et al. [179] make suggestions and
argue that it might be promising to broaden the
focus from operations research techniques to the
economic and project management aspects of
surgery scheduling. Additionally, Vissers et al.
[262] suggest to put a larger emphasis on the mul-
tidisciplinary aspects of patient flow control sys-
tems and suggest to experiment with the effect of
grouping patients in new ways, such as based on
their length of stay (LOS) or surgery duration.
Furthermore, several authors emphasize that
more research could be done on on-line reschedul-
ing performed close to or on the day of surgery.
Dexter et al. [73] provide a review on the few pa-
pers that include that type of decisions and empha-
size the importance of the following four points:
patient safety, open access to OR time, maximiz-
ing OR efficiency (defined as minimal overutilized
OR time) and minimizing patient waiting time.
Other reviews emphasize the need for more de-
tailed models on the seasonality of demand, for
more realistic constraints for surgeon and patient
preferences and for a larger focus on the entire
care pathway.
We generally observe in reviews that topics
such as staffing are often excluded and thus treated
separately from the resource related decision mak-
ing problems. Finally, we also observe that, un-
like in the diagnostic imaging scheduling litera-
ture, most focus is on models where patients are
scheduled in batches and not one-by-one.
4 M. Samudra, C. Van Riet, E. Demeulemeester, B. Cardoen, N. Vansteenkiste, F. Rademakers
Table 2 Existing reviews differ in their scope (rows) and
classification structure (columns)
Hierarchical Custom
categories categories
OR [105, 112] [42, 60, 73, 82, 109,
167, 179, 210, 219]
Hospital [26, 27, 32, 262] [27, 32, 137, 231, 232,
250, 255]
Health care [112, 127, 128] [36, 110, 112, 127,
128, 207]
Reviewing the literature according to hierarchal categories
is a common approach. Articles appearing twice in the ta-
ble use a multi-dimensional classification structure
In this review, we propose a structure that is
based on descriptive fields. We are not using hier-
archical levels, since the boundaries between these
levels can vary considerably for different settings
and hence are often perceived as vague and in-
terrelated [230]. Furthermore, this categorization
seems to lack an adequate level of detail.
Moreover, other taxonomies that use one spe-
cific characteristic of the paper (e.g., solution tech-
nique), might prohibit the reader from easily find-
ing a paper on a certain topic. For example, when
a researcher is interested in finding papers on OR
utilization, a taxonomy based on the solution tech-
nique does not seem very helpful. We think that
the use of descriptive fields avoids these prob-
lems.
3 Descriptive Fields
Each field analyzes articles from a different per-
spective, which can be either problem or tech-
nically oriented. In particular, we distinguish be-
tween seven fields:
• Patient characteristics (Sect. 3.1): reviewing
the literature according to the elective (in-
patient, outpatient) or non-elective (urgency,
emergency) status of the patient;
• Performance measures (Sect. 3.2): discussing
the performance measures (PM) such as uti-
lization, idle time, waiting time, preferences,
throughput, financial value, makespan and pa-
tient deferral;
• Decision delineation (Sect. 3.3): indicating
what type of decision has to be made (date,
time, room and capacity) and whether this de-
cision applies to a medical discipline, a sur-
geon or a patient (type);
• Supporting facilities (Sect. 3.4): discussing
whether an approach includes supporting
units, e.g., PACU and ICU;
• Uncertainty (Sect. 3.5): indicating to what
extent researchers incorporate uncertainty
(stochastic versus deterministic approaches);
• Operations research methodology (Sect. 3.6):
providing information on the type of analysis
that is performed and the solution or evalua-
tion technique that is applied;
• Testing phase (Sect. 3.7): covering the infor-
mation on the testing (data) of the research and
its implementation in practice.
The structure we use is meant to balance be-
tween simplicity and comprehensiveness. It pro-
vides a simplified, but in our belief for the ma-
jority of the readers sufficiently accurate way to
identify and select articles they are interested in.
The tables list and categorize all researched ar-
ticles. Pooling them over the several fields enables
the reader to reconstruct the content of a specific
paper. They furthermore act as a reference tool to
obtain the subset of papers that correspond to a
certain characteristic.
Each section clarifies the terminology if
needed and includes a brief discussion based on
a selection of appropriate articles. Plots are pro-
vided for a selection of characteristics to point out
the trends set by the research community. It should
be noted that the percentages are calculated in re-
lation to the total amount of technical papers. Also
note that some fields are not interpretable for some
methods and even though rare, some articles con-
tain more than one single method. Moreover, the
values for each year in the plots represent the aver-
age of the previous, the current and the next year.
Using this moving average allows to spot larger
research trends in an easier way. After all, a year
with fewer publications does not imply that the
topic has not been researched in that year.
Finally, in the last part (Sect. 3.8) we go one
step further and analyze the connection between
different classification fields. This provides in-
sights into research practices.
3.1 Patient Characteristics
Two major patient classes are considered in the lit-
erature: elective patients and non-elective patients.
The former class represents patients for whom the
surgery can be planned in advance, whereas the
latter class groups patients for whom a surgery is
unexpected and hence needs to be fitted into the
