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Original Article
Corresponding Author
Richard Philip Menger
https://orcid.org/0000-0002-6426-2187
Department of Neurosurgery, LSU Health
Sciences Center-Shreveport, 1501 Kings
Highway, Shreveport, LA 71130-3932,
USA
Tel: +1-318-675-6404
Fax: +1-318-675-5000
E-mail: richard.menger@gmail.com
Received: March 14, 2018
Revised: June 5, 2018
Accepted: July 1, 2018
A Cost-Eectiveness Analysis of the
Integration of Robotic Spine
Technology in Spine Surgery
Richard Philip Menger1,2, Amey R. Savardekar1, Frank Farokhi1, Anthony Sin1,2
1Department of Neurosurgery, Louisiana State University Health Sciences Center, Shreveport, LA, USA
2Shriners Hospital for Children, Shreveport, LA, USA
Objective: We investigate the cost-eectiveness of adding robotic technology in spine sur-
gery to an active neurosurgical practice.
Methods: e time of operative procedures, infection rates, revision rates, length of stay,
and possible conversion of open to minimally invasive spine surgery (MIS) secondary to ro-
botic image guidance technology were calculated using a combination of institution-specic
and national data points. is cost matrix was subsequently applied to 1 year of elective
clinical case volume at an academic practice with regard to payor mix, procedural mix, and
procedural revenue.
Results: A total of 1, 985 elective cases were analyzed over a 1-year period; of these, 557
thoracolumbar cases (28%) were analyzed. Fiy-eight (10.4%) were MIS fusions. Indepen-
dent review determined an additional ~10% cases (50) to be candidates for MIS fusion.
Furthermore, 41.4% patients had governmental insurance, while 58.6% had commercial
insurance. e weighted average diagnosis-related group reimbursement for thoracolumbar
procedures for the hospital system was calculated to be $25,057 for Medicare and $42,096
for commercial insurance. Time savings averaged 3.4 minutes per 1-level MIS procedure
with robotic technology, resulting in annual savings of $5,713. Improved pedicle screw ac-
curacy secondary to robotic technology would have resulted in 9.47 revisions being avoid-
ed, with cost savings of $314, 661. Under appropriate payor mix components, robotic tech-
nology would have converted 31 Medicare and 18 commercial patients from open to MIS.
is would have resulted in 140 fewer total hospital admission days ($251,860) and avoided
2. 3 infections ($36, 312). Robotic surgery resulted in immediate conservative savings esti-
mate of $608,546 during a 1-year period at an academic center performing 557 elective
thoracolumbar instrumentation cases.
Conclusion: Application of robotic spine surgery is cost-eective, resulting in lesser revi-
sion surgery, lower infection rates, reduced length of stay, and shorter operative time. Fur-
ther research is warranted, evaluating the nancial impact of robotic spine surgery.
Keywords: Cost analysis, Cost eectiveness, Robotic spine surgery
INTRODUCTION
Applications of robotics have demonstrated utility across a
wide spectrum of surgical specialties.1 Still, robotic surgery is in
its nascent stages in the field of spinal surgery. Recent literature
pertaining to the application of robotics in spinal instrumenta-
tion has revealed that robotics has the potential to revolutionize
this aspect of spinal surgery in terms of better accuracy rates for
screw placements, decreased operative time, less fluoroscopic
exposure to the surgical team, and possible more conversion to
minimally invasive techniques.1 In addition to these aspects,
the cost-effectiveness of robotics in spinal surgery is likely to
play an important role in its eventual assimilation into everyday
practice.
Neurospine 2018 August 29 [Epub ahead of print]
https://doi.org/10.14245/ns.1836082.041
N
eurospine
eISSN 2586-6591 pISSN 2586-6583
This is an Open Access article distributed under
the terms of the Creative Commons Attribution
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mons.org/licenses/by-nc/4.0/) which permits
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Copyright © 2018 by the Korean Spinal
Neurosurgery Society
Cost-Effectiveness of Robotic Spine SurgeryMenger RP, et al.
https://doi.org/10.14245/ns.1836082.041
2 www.e-neurospine.org
Between 2001 and 2010, approximately 3.6 million spinal fu-
sions were performed, with an estimated total cost of $287 bil-
lion in the United States alone.2 Considering these high costs,
spine surgeons are coping with pricing pressures and increased
accountability for their performance.3 Amidst this, there is an
initiative to improve the value that we, as spine surgeons, deliv-
er to our patients: better outcomes and lower costs. The appli-
cation of robotic systems to spinal surgery may play a vital role
in implementation of such a value-based spinal care. Although
the initial capital investment would be large (current pricing on
urologic robotics is approximately $1.5 to 2 million), the benefit
in patient volume, better accuracy and improved long-term out-
comes can justify the utilization of these systems.4
Robotic surgery has significantly changed practice patterns
in urologic surgery.5 The available literature on the cost-effec-
tiveness of robotic urologic surgery however reveals that although
post-operative outcomes are similar, robotic-assisted laparoscop-
ic surgery is more costly than laparoscopic and open surgery.4,5
Whether long-term outcomes may be more cost-effective with
robotic-assisted systems remains to be proven.5 Such cost-effec-
tiveness analysis are imperative to understand the problems and
accordingly implement solutions.5
Here we apply a cost-effectiveness analysis on the application
of robotic technology to spine surgery across a busy academic
neurosurgical practice. The purpose is to gain an early insight
towards utilization of the robotic platform in the value-based
healthcare model for spinal surgery.
MATERIALS AND METHODS
The impact of robotic technology on spinal surgery was mod-
eling using a combination of institution specific and nationally
related data points.
1. Patient Cohort
This study was approved by the Institutional Review Board
of LSUHSC, Shrevport (approval number: MODCR0000472_
H13-020). Data was integrated retrospectively to 1985 consecu-
tive patients whose data was previously prospectively gathered
across six different neurosurgical providers at Louisiana State
University Health Sciences Center in Shreveport, LA, USA. This
was done during the period of July 1, 2014 to June 30, 2015. Five
hundred and fifty-seven patients specifically underwent thora-
columbar instrumentation procedures. This temporal cohort
specifically was analyzed due to the detailed procedural log, clin-
ical information, and socioeconomic information available. Data
was intentionally applied to only elective cases to ensure that
planned utilization of possible robotic technology could be rea-
sonably applied to the surgeon’s decision-making. Emergent
cases and hospital consultation requiring immediate in-house
surgical procedures were not considered in this study by the
basis of economic evaluation. All patients scheduled for neuro-
surgical procedures who presented through the outpatient clin-
ic were considered for this study regardless of attending, surgi-
cal procedure, or hospital location.6
2. Payer Mix and Procedural Mix
The appropriate payer mix (Medicare, Medicaid, Commer-
cial, or other insurance) for the cases performed was recorded
from the patient specific dataset. This has been previously doc-
umented.6 The construct of governmental insurance included
Medicare, Medicaid, and military insurance (Tricare). Despite
being a managed care platform, Tricare insurance reimburses
closer to Medicare rates than commercial insurance and as such
was included in that cohort. Medicaid (1%) and Tricare (3.4%)
represented only 4.4% of patients in the series and as such, the
gross assumption was made to equate all governmental reim-
bursement to Medicare rates. For purposes of this study, the di-
agnosis related group (DRG) was considered to be a reimburse-
ment of 100%.6 Medicare reimbursement served as a benchmark
with reimbursement for those with commercial insurance, which
reimburses 168% for Medicare severity-DRG (MS-DRG).7
Procedural revenue was calculated using the appropriate na-
tional averages for MS-DRG payment for specific spinal proce-
dures.8 In order to calculate and appropriately weighted average
DRG estimate, national data involving the incidence of the uti-
lization of spine specific DRG codes was performed. The aver-
age DRG for thoracolumbar procedures was calculated at $25,057
for Medicare and $42,096 for commercial insurance for the
hospital system. This incorporated both disease pathology as
well as medical comorbidities. The average weighted DRG was
calculated from nationally available data illustrating the reim-
bursement for MS-DRG and the national distribution of MS-
DRG incidence between different neurosurgical disease bun-
dles.8
Operating room (OR) cost was calculated at $18 per minute
which is a hospital-generated specific institutional number com-
bining both fixed and variable cost. Per hospital administration
calculation, this was 50% fixed and 50% variable cost. This falls
within the national estimates for OR cost of $15–20.9 Time sav-
ings with utilization of robotic technology was estimated from
previously published data.10
Cost-Effectiveness of Robotic Spine SurgeryMenger RP, et al.
https://doi.org/10.14245/ns.1836082.041
www.e-neurospine.org 3
3. Clinical Data Points
Reoperation rates secondary to pedicle screw misplacement
were estimated from nationally available data. This included a
2.7% revision rate for open cases and a 0.4% revision rate for
minimally invasive spine surgery (MIS) cases. The incidence of
reoperation due to pedicle screw misplacement for surgeries
with robotic assistance was constructed as 0%.11 Average cost of
the revision was adapted from earlier published data from Wat-
kins et al. 2010 in the Cost Effectiveness of Image-Guided Spine
Surgery in the The Open Orthopedics Journal as $23,762 for
Medicare and $39,920 for private payors.12 Previously presented
institution specific infections rates for the comparison of open
instrumentation (4.6%) and MIS instrumentation procedures
(0%) were used.13 Average cost of a spinal infection was adapted
from earlier published data from McGirt et al. as $15,817.14,15
Difference in the average of length of stay (LOS) between MIS
and open spinal procedures was estimated as 2.8 days from pre-
viously established systematic review of the literature.16 Cost
per hospital floor bed per day was noted as $1,799. This was
adapted from Kaiser Family Foundation for data specific to Loui-
siana nonprofit hospitals.17
The procedural impact of robotic technology was calculated.
Cases previously performed underwent an independent review
by a nonprimary surgeon and final review by the primary sur-
geon for the applicability of transition to minimally invasive
technology by use of robotic technology. This was estimated to
be at approximately 10% of cases in which the minimally inva-
sive approach was abandoned due to the specific procedural
challenges of percutaneous instrumentation.
Finally, based on previous historical integration of new image
guided navigation technology in spine surgery at our institution,
the utilization of the robot on otherwise open cases was estimat-
ed at 75%.
4. DRG and Cost
DRG was used as a surrogate for cost. Medicare adapted a
prospective payment system in 1982. DRG represented a bun-
dled prospective payment per each encounter with modifiers
for patient severity. The vital distinction is that DRG represents
how much a hospital is paid for the treatment of a certain pa-
thology for a certain patient. It attempts to link the costs the
hospital incurs for treatment of a certain patient classification.
It does not necessarily represent the true cost the hospital re-
quires for treatment of the patient.18
As such, the concept of estimating cost on the basis of weight-
ed DRG proposal has been established.19 There exists for for-
ward thinking value based cost algorithms.20 However, on the
current basis of volume based payment the DRG is used here.
RESULTS
During the academic year 557 patients underwent elective
Table 1. Payor mix
Insurance carrier Percent of patients Average % of DRG*
Government†41.4% 100%
Commercial 58.6% 168*
Adapted from Louisiana State University Health Sciences Center
elective surgical volume payor mix.
DRG, diagnosis-related group.
*Assumed to be Medicare (Medicare 37%, Medicaid 1%, and mili-
tary 3.4%).
Table 2. Impact of robotic technology on procedural distribution
Insurance
carrier
Current open
procedures
Current
MIS
Projected open
robot procedures*
Projected conversion of MIS
cases with robotic technology†
Projected total MIS
robotic procedures
Total projected
robotic spine surgeries
Medicare 207 24 139 21 39 178
Commercial 292 34 197 29 55 252
Tota l 499 58 337 50 93 430
MIS, minimally invasive spine surgery.
*Assumes 75% utilization of robotic technology when purchased. †Assumes 10% increase in MIS approach with robotic technology.
Table 3. Impact of robotic technology on revision rates
Insurance
carrier
Procedures converted from
conventional to robot Revisions avoided*
Open MIS Open MIS
Medicare 139 39 3.77 0.15
Private pay 197 55 5.33 0.22
Tota l 336 94 9.10 0.37
MIS, minimally invasive spine surgery.
*Assumes 2.7% revision rate for open surgery, 0.4% revision rate for
MIS surgery, 0% revision rate for robotic surgery.
Cost-Effectiveness of Robotic Spine SurgeryMenger RP, et al.
https://doi.org/10.14245/ns.1836082.041
4 www.e-neurospine.org
thoracolumbar fusion out of a total of 1985 elective cases (28%).
Fifty-eight of 557 (10.4%) were minimally invasive fusions in
the thoracic or lumbar spine. Independent review noted that
approximately another 10% of cases would be candidates for
minimally invasive fusion. Data regarding specific payor mix
components is noted in Table 1. This included 63.0% of patients
being governmental insurance based. The weighted average
DRG is calculated at $25,057 for Medicare and $42,096 for com-
mercial insurance. Time savings was averaged at 3.4 minutes
per average 1-level MIS procedure. A total of 50 patients were
determined to be candidates for conversion from open to MIS
procedure due to robotic technology. Under the appropriate
payor mix algorithm, this would have resulted in 31 new Medi-
care MIS cases and 18 new private payor MIS cases. Table 2 il-
lustrates the procedural impact of robotic technology. Table 3
illustrates the impact on revision surgery.
Overall, the estimated cost of infections was substantial with
an additional $363,116 of cost. Adaption of robotic surgery could
lower that cost to $326,804 with a savings of $36,312. The eco-
nomic impact of infection reduction can found in Table 4. Ro-
botic surgery resulted in an immediate conservative estimate
cost savings of $608,546. This is summarized in Table 5.
DISCUSSION
To our knowledge, our study is the first to critically analyze
the economic impact of robotic technology on a practicing health-
care system as it relates to spinal surgery. Specifically, improved
screw accuracy due to computer-assisted navigation inherent to
robotic surgery results in decreased revision surgeries, and it al-
lows for the conversion of more cases to MIS. This results in
fewer postoperative infections and reduced LOS in the hospital.
Furthermore, robotic surgery can also reduce operative time.
Based on these assumptions, which have been documented
in literature, we created a model in which robotic-assisted spine
surgery was utilized to treat those patients who were amenable
for this technology. Robotic surgery led to savings of $608,546
over a 1-year period, considering a case-load of 557 cases. Even
though the initial cost of acquisition of the system and mainte-
nance charges need to be considered, it can be hypothesized
that robotic-assisted spine surgery is likely to result in cost ben-
efits over the long term. This is in addition to mitigating much
of the harmful radiation exposure in MIS to which the patient,
surgeon, and ancillary OR staff are subjected.
1. Robotics in Surgery
Advances in robotic surgery have been taking place since the
1980’s. Research by private and governmental entities ultimate-
ly resulted the da Vinci Surgical System (Intuitive Surgical Inc.,
Sunnyvale, CA, USA). Approved by the U.S. Food and Drug
Administration (FDA) in 2000, the da Vinci robot has been
shown to offer safety, efficiency, cost reduction, and even im-
munological benefits for surgical procedures.21 By 2015, over
700,000 surgeries had been performed with the da Vinci Sys-
Table 4. Impact of robotic technology on infection rates
Technology Total open
procedures
Open
infections*
Total MIS
procedures
MIS
infections*
Total cost of
infections†
Infections prior to robotic technology 499 23.0 58 0$363,116
Infections with robotic technology 449 20.7 108 0$326,804
Savings ----$36,312
MIS, minimally invasive spine surgery.
*4.6% infection rate for open surgery 0.0% infection rate for MIS surgery per institutional data. †Assumption $15,817 cost of infection.
Table 5. Cost avoidance with robotic spine technology
Vari ab le Case number Impact Annual savings
Time 93 MIS robotic surgeries 317 Minutes of time savings in MIS cases* $5,713
Revisions 430 Robotic surgeries (MIS/open) 9.47 Revisions avoided $314,661
Infection rates 50 Patients converted from open to MIS cases 2.30 Infections avoided $36,312
Length of stay 50 Patients converted from open to MIS cases 140 Number of ward days reduced†$251,860
Tota l $608,546
MIS, minimally invasive spine surgery.
*Assumes 3.4 minutes of time saved per MIS case. †Assumes difference of 2.8 days per length of stay (open vs. MIS).
Cost-Effectiveness of Robotic Spine SurgeryMenger RP, et al.
https://doi.org/10.14245/ns.1836082.041
www.e-neurospine.org 5
tem, demonstrating widespread acceptance and utilization of
surgical robotics.
Of particular interest at this moment in healthcare history is
the cost-savings associated with the use of surgical robots. While
the initial capital investment is large (current pricing on a single
da Vinci Robot is approximately $1.5 to 2 million), the benefit
in patient volume and improved outcomes can justify the utili-
zation of these systems. Cost assessment of robotics in different
surgical specialties is a recent and on-going endeavor and pres-
ent evidence suggests that robotic surgery, under specific con-
ditions, has the potential to become cost-effective.22 Large num-
ber of cases, presence of industry competition, and multidisci-
plinary team utilization are some of the factors that could make
robotic-assisted surgery make more reasonable and cost-effective.
2. Robotics in Spine Surgery
Spine surgery has been revolutionized due to rapid techno-
logical advancements taking place in the last two decades. The
goals of these improvements have been to achieve of a high de-
gree of precision, minimize risks of damage to neurovascular
structures, facilitate surgeon access and OR dynamics, and di-
minish harmful exposure to ionizing radiation in patients and
the operative team.1 Because the risks associated with spine sur-
gery are plentiful, and limiting complications is imperative, im-
plementing a robot-assisted technique has the potential to ad-
dress many concerns associated with conventional surgery. At
the same time, cost-effectiveness of this technology needs to be
carefully reviewed in the context of current value-based care
models with emphasis on judicious allocation of healthcare dol-
lars.23 This is of particular importance in the multibillion dollar
spine surgery industry.
One of the pioneers, and by far the most studied of these ro-
botic-assisted surgical devices for spine surgery, is the Spine-
Assist/Renaissance robot (MAZOR Robotics Inc., Orlando, FL,
USA).23 Several clinical studies have analyzed the translational
accuracy and efficacy of the Spine-Assist robot (MAZOR Ro-
botics Inc.) in vivo. Roser et al.,24 found a 99% accuracy rate of
lumbosacral pedicle instrumentation using the Spine-Assist
robot compared to 98% utilizing fluoroscopy guided, and 92%
using traditional navigation techniques. Schizas et al., reported
a 95% accuracy rate vs. 92% for robot-assisted vs. fluoroscopic-
guided lumbosacral pedicle screw instrumentation, and Kan-
telhardt et al. similarly showed 95% accuracy vs. 92% using
Spine-Assist and conventional fluoroscopy, respectively.25,26 The
only study to date demonstrating a reduced accuracy of screw
placement came from Ringel et al.27 in a randomized controlled
trials (RCT) that demonstrated a significantly reduced accuracy
rate of lumbosacral pedicle screw instrumentation with the Spine-
Assist robot (85%) compared to fluoroscopic-guided screws
(93%).
In a new application of an existing surgical robot, the ROSA
robot by Medtech (Medtech S.A., Montpellier, France), may
help mitigate concerns of fixation strength to bony anatomy
like those encountered by Ringel et al.23,27 In their preliminary
study on the novel application of the ROSA robot for spinal sur-
gery, Lonjon et al.,28 reported an accuracy rate of 97.3% for ped-
icle screw instrumentation compared to 92% in the free-hand
(FH) group.
The Da Vinci Surgical System (Intuitive Surgical Inc.) has
been utilized for laparoscopic anterior lumbar interbody fusion
with promising results; however, its use is not FDA-approved
for actual spinal instrumentation and more exploration is nec-
essary to validate its utility in spine surgery.23
3. Conversion to Minimally Invasive Technique
Our series estimated a 10% conversion rate to minimally in-
vasive technology. MIS of the spine is increasing in popularity
and widespread practice. The tubular systems, which were first
used for laminectomy and discectomy, have now been adapted
to perform multilevel fusions. In 2010, approximately one sixth
of all instrumented spine procedures were performed by MIS
techniques. By 2016, that number had increased to almost one
third. It is projected that half of all spinal instrumentation sur-
geries will be performed MIS by 2020.29 A recently published
meta-analysis of 602 patients across 10 studies demonstrates
decreased LOS, reduced intraoperative blood loss, fewer post-
operative complications, and similar long-term outcomes based
on validated outcome measures.30 A follow-up paper that stud-
ied 345 patients enrolled in a prospective, national spine regis-
try, treated by both orthopedic and neurological surgeons at 11
institutions across the United States, demonstrated no differ-
ence with regard to 12-month patient reported outcomes, LOS,
and 90-day return to work.31 Parker et al.32 also suggested that,
at 2 years, overall cost-per-patient was reduced.
4. Quantifying the Intraoperative Benefits of Robotic
Assistance in Spine Surgery
Across all studies, the same important metrics are analyzed:
accuracy of hardware placement, radiation exposure, learning
curves for surgeons, and patient outcomes. Of these, the major
limiting factors for the application of MIS techniques include
surgeon learning curves and physician radiation exposure.23
Cost-Effectiveness of Robotic Spine SurgeryMenger RP, et al.
https://doi.org/10.14245/ns.1836082.041
6 www.e-neurospine.org
The following sections discuss the current research into each of
these metrics.
5. Radiation Exposure
Robotic surgery can help reduce radiation exposure. The stan-
dard metric for this is the fluoroscopy time (FT), and some pa-
pers analyze the actual doses in millisieverts (mSv). The recent
paper by Joseph et al.1 described 10 recent studies that analyzed
this metric. Five of these studies compared FH to robotic place-
ment, and all 5 found the FT to be similar or decreased in the
robotic group as compared to FH group. Roser et al.24 also in-
cluded the standard navigation group and found this group to
have the overall lowest FT. Sensakovic et al.33 developed a low-
dose computed tomography (CT) protocol for their patients for
pre-operative imaging with significant reductions in mSv per
patient. From this data, it seems likely that FT and mSv will both
be reduced. However, this seems directly related to surgeon tech-
nique and the learning curve of robotic surgery.
Vaccaro et al.,10 in their comparative analysis of 40 pedicle
screw insertions in each arm (conventional MIS screw place-
ment vs. robotic-assisted screw placement), noted that the con-
ventional MIS placement required 108 intraoperative fluoro-
scopic images, while the robotic group resulted in no radiogra-
phic images. Thus, surgeons and the OR staff were subjected to
zero radiation in the robotic-assisted screw placement. With
both improved screw accuracy and decreased radiation expo-
sure, it remains plausible to see an increase in MIS techniques
secondary to robotic technology.
6. Pedicle Screw Insertion Accuracy and Revision Rates
Verma et al.,34 conducted the first of several meta-analyses on
the topic of pedicle screw accuracy and safety of implantation
with computer-assisted navigation (CAN), and reviewed 23
studies evaluating 5,992 pedicle screws. They found a signifi-
cantly higher rate of accuracy utilizing CAN; however, though
the rate of neurological injury favored navigation, the group
failed to demonstrate statistical significance. Gelalis et al.,35 re-
viewed 26 studies and 6,617 pedicle screws inserted FH, with
fluoroscopic guidance or with CAN. While they found no sig-
nificance between the fluoroscopic and navigation assisted meth-
ods, both exhibited statistically superior accuracy as compared
to FH technique. However, their analysis failed to demonstrate
a significantly lower rate of screw revision or total reoperation
rates and no difference in neurological injury. In the most re-
cent meta-analysis, Shin et al.36 used stringent exclusion criteria,
including exclusion of noncomparative studies using differing
platforms for navigation guidance, studies without explicit com-
plication data, and studies examining cervical pedicle screws
resulting in only 12 studies evaluating 4,953 screws. They dem-
onstrated significantly increased screw accuracy with CAN.
Perhaps due to their strict inclusion criteria, they also reported
a significantly lower rate of screw-related complications in the
navigation cohort as compared to FH.
A recent systematic literature review identified 25 studies that
characterized the role of robots in spinal surgery; 18 retrospec-
tive studies, 7 prospective studies, and 4 RCTs were identified.1
Twenty-two of these studies evaluated the accuracy of instru-
mentation placement. Many of these studies relied on the post-
operative, CT-based Gertzbein and Robbins system (GRS) to
classify pedicle screw accuracy.37 According to the GRS, screws
completely within the pedicle are considered grade A; a breach
of <2 mm is grade B; a breach of 2 to < 4 mm is grade C; a breach
of 4 to <6 mm is grade D; and a breach of > 6 mm is grade E.
In this system, both grades A and B are deemed acceptable for
screw placement.38 Across all studies, robot-assisted pedicle
screw placement was highly accurate. Interestingly, the very
first RCT by Ringel et al.25 found a significantly lower rate of ac-
curacy using the robot (GRS grade A or B : 85% in the robotic
group vs. 93% in the FH group). Two follow-up RCTs by Kim
et al.39 and Hyun et al.40 found similar accuracy between robotic
placement and freehand placement, but both studies demon-
strated no proximal facet disruption using the robot, whereas
FH technique saw up to 15.9% violation. All other studies in
this group saw an increase in accuracy using robotic assistance.
Interestingly, the RCT conducted by Roser et al.24 found both
robotic and FH accuracy superior to standard navigated tech-
nique. Limitations of these studies were usually related to small
sample sizes, with most studies having less than 100 patients
enrolled. There have been newer studies published this year
with larger sample sizes. Molliqaj et al.37 described a cohort of
169 patients with 880 screws places (439 in the robot group vs.
441 in the freehand group). They found that perfectly placed
screws (GRS grade A) were found in 83.4% of robotically placed
screws versus 76% in the freehand technique. A recent publica-
tion from Kantelhardt’s group retrospectively analyzed implan-
tation of 2,067 robotically assisted pedicle screws in 406 patients.41
They classified 1,799 screws (96.9%) as having an acceptable or
good position, whereas 38 screws (2%) showed deviations of
3–6 mm and 20 screws (1.1%) had deviations >6 mm. They
quoted a FH accuracy rate ranging from 65%–94% based on
literature review. With the exception of a single study, most
studies demonstrate improved accuracy and lower revision
Cost-Effectiveness of Robotic Spine SurgeryMenger RP, et al.
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www.e-neurospine.org 7
rates among robotically placed pedicle screws. Clearly, improved
pedicle screw accuracy improves clinical outcomes and would
reduce overall cost.
7. OR Time
OR time is a valuable resource of any surgeon or hospital sys-
tem. Expert spinal surgeons in both neurosurgery and orthope-
dic surgery performed a cadaveric study illustrating the accura-
cy and timing of robot-assisted pedicle screw placement.10 Eight
pedicle screws were inserted by each surgeon from L2–5 with
one side being traditional MIS fluoroscopic guided and the oth-
er being robotic guided using a leading spinal robot. Record
time for both techniques included the technical exercise of screw
placement (incision, drill, tap, and insertion) as well as equip-
ment set-up. Conventional MIS screw placement was 36 min-
utes while robotic assistance was 32.6 minutes for four screws.
This was inclusive of the 18.3 minutes required for the set-up of
the robot. The MIS pedicle screw took 7.6 minutes for physi-
cian insertion. The robotic screw took 3.6 minutes for physical
insertion independent of set-up time. Zero breaches were seen
in the robotic arm. A 17.5% breach rate (7 of 40) was seen in
the traditional MIS C-arm group. On average, 108 radiographs
were used for the placement of traditional MIS screws.10
It is worth noting, as with implementation of any new tech-
nology, there is a learning curve associated with robotic-assist-
ed spine surgery. Joseph et al.,1 analyzed the learning process in
8 studies. Across all 8 studies, a notable reduction in per-screw
time and FT was noted. Devito et al.,42 noted an improvement
in accuracy from 83.7% to 90.8% from early to later cases, as
well as a minutes-per-level decrease from 13.5 to 10.6. Kim et
al.,39 and Hyun et al.,40 also noted a surprisingly similar rate of
improvement. Thus, over time OR time is likely improve with
any new technology including robotic-assisted surgery.
8. Limitations
As within any modeling algorithm, discrepancies in factual
minutia are apparent. Most glaringly, the operative time-savings
was grossly applied from MIS pedicle screw placement com-
parison across only 10 different surgeons for specific MIS cases.
This however is the only available data-set involving time mea-
surements of the robotic time for placement of pedicle screws.
It provides some insight into the utilization of time in the oper-
ative theatre. Moreover, the importance of the data focuses on
the application of minimally invasive technology to a new co-
hort of patients. This, by previous study, has been shown to re-
duce infection, reduce LOS, and reduces revision surgery.
Beyond the scope of this paper is the real and significant cost
of robotic surgery as a capital item purchase. The cost of robotic
technology can be taken directly from industry disclosed infor-
mation. This includes both fixed costs of capital and service
charge as well as variable costs per case. Cost of spinal instru-
mentation to the hospital system can also vary between health-
care enterprises. This however is not in the scope of societal
cost savings as differing health systems can use robotic technol-
ogy as a marketing tool to capture patient and payor mix in a
regional fashion. The assumed model is used to look specifical-
ly at the possibility of hospital-based societal cost savings in the
delivery of health care. The purpose is to illustrate how robotic
technology, not a specific robotic device, can generate a cost
savings through real patient and simulated cost data at a specif-
ic institution. Different robotic devices, and different genera-
tions of robotic devices, will have variable start-up costs. This is
a variable can be manipulated at the hospital level based on things
like negotiation and scale.
Further limitations of this analysis include lack of inferential
statistics, and biases relating to descriptive analysis. Additional-
ly, the cost estimates are derived from previously published lit-
erature, and therefore may not be reflective of the current era
given the lack of inflation adjustments.
Further investigation is sincerely warranted regarding the ap-
plication and cost effectiveness of robotic imaging guidance in
specific clinical procedures. This includes lateral spine surgery
and deformity surgery. Beyond modeling, direct clinical obser-
vation of the application of robotic technology is warranted.
CONCLUSION
The application of robotic surgery can be a cost-effective emerg-
ing technology resulting in decreasing revision surgery, decreas-
ing infection rates, reducing LOS, and shortening operative
time. Modeling at a major academic center resulted in an esti-
mated $608,546 of savings in one academic year. Future investi-
gations are essential in understanding the impact of robotic tech-
nology on specific procedures.
CONFLICT OF INTEREST
The authors have nothing to disclose.
ACKNOWLEDGMENTS
The authors wish to thank Lance Butler Imaging, Navigation
Cost-Effectiveness of Robotic Spine SurgeryMenger RP, et al.
https://doi.org/10.14245/ns.1836082.041
8 www.e-neurospine.org
& Robotics at Globus Medical Incorporated (Audubon, PA) for
his assistance in the acquisition of industry specific data.
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