Original Research—Sinonasal Disorders
Comparing the Reverse Trendelenburg
and Horizontal Position for Endoscopic
Sinus Surgery: A Randomized
Controlled Trial
Otolaryngology–
Head and Neck Surgery
148(2) 308–313
Ó American Academy of
Otolaryngology—Head and Neck
Surgery Foundation 2013
Reprints and permission:
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DOI: 10.1177/0194599812466529
http://otojournal.org
Iain F. Hathorn, MBChB, FRCSEd1, Al-Rahim R. Habib1,
Jamil Manji1, and Amin R. Javer, MD, FRCSC1
No sponsorships or competing interests have been disclosed for this article.
Received August 6, 2012; revised September 21, 2012; accepted
October 11, 2012.
Abstract
Objective. To determine whether the 15-degree reverse
Trendelenburg position (RTP) during functional endoscopic
sinus surgery improves endoscopic field of view and reduces
intraoperative blood loss when compared with the horizontal position (HP).
Study Design. A prospective, randomized controlled trial.
Setting. St Paul’s Sinus Centre, Vancouver, Canada.
Subjects. Patients with chronic rhinosinusitis (CRS), with or without nasal polyposis, receiving functional endoscopic sinus surgery
were included. Patients were excluded if they had severe or
uncontrolled hypertension and cardiovascular disease, continued
use of anticoagulants, impaired coagulation, or a sinonasal tumor.
Methods. Sixty-four patients with CRS undergoing functional
endoscopic sinus surgery (FESS) were randomized to either
15-degree RTP (experimental arm) or HP (control arm) from
October 2011 to February 2012. Boezaart endoscopic field-ofview grading system was the primary outcome measure. LundMackay computed tomography (CT) score, total blood loss,
blood loss per minute, mean arterial pressure, heart rate,
anesthetic technique, and surgery time were also recorded.
Results. There was a significant difference in mean Boezaart
scoring between RTP and HP: 1.66 vs 2.33 (P \ .001), with
RTP producing a better endoscopic field of view. There was
also a lower total blood loss and blood loss per minute with
RTP (P = .01, P = .03). There was no significant difference in
disease severity (P . .05), time of surgery (P . .05), or mean
arterial pressure (P . .05) between the 2 surgical positions.
Conclusion. The 15-degree RTP improves the endoscopic
field of view and reduces blood loss during FESS. We would
therefore recommend its use.
Keywords
reverse Trendelenburg position, endoscopic sinus surgery,
intraoperative bleeding, surgical field
B
ecause of the highly vascular nature of the sinonasal mucosa and the narrow surgical area, small
amounts of blood can substantially impair endoscopic visualization of surgical field. Any obstruction of the
endoscopic field of view may increase the risk of surgical
complications. Several techniques can be used to control
blood loss and improve surgical field during sinus surgery,
such as preoperative corticosteroid treatment,1 local vasoconstrictors,2 controlled hypotension,3-6 and total intravenous anesthesia (TIVA).7 A simpler method to achieve the
same goal may be adjusting patient position.
Functional endoscopic sinus surgery (FESS) performed
in the horizontal position is standard at the St Paul’s Sinus
Centre. Surgeon experience has found that placing patients
in the horizontal position (HP) allows for consistent orientation of the sinus anatomy and in particular the skull base.
The horizontal position with the surgeon sitting while operating is standard practice in many tertiary North American
sinus centers (unpublished data). However, the reverse
Trendelenburg position (RTP), a head-up, feet-down tilt
varying from 10 to 30 degrees, is also commonly used
during FESS.8,9 The RTP reduces venous return and cardiac
output by retaining blood in the lower parts of the body.10,11
It has been shown to decrease blood loss in neurosurgery,
where it is commonly used to reduce intracranial pressure,10,12-14 and in abdominal surgery.11 There is, however,
surprisingly little literature specifically looking at FESS and
the effect of RTP.
1
Division of Otolaryngology, University of British Columbia, St Paul’s Sinus
Centre, Vancouver, British Columbia, Canada
This article was presented at the 2012 AAO-HNSF Annual Meeting & OTO
EXPO; September 9-12, 2012; Washington, DC.
Corresponding Author:
Iain F. Hathorn, St Paul’s Sinus Centre, 1081 Burrard Street, Vancouver, BC,
V6Z 1Y6
Email: iainhathorn@hotmail.com
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Hathorn et al
Table 1. Boezaart Scale for Endoscopic Surgical Field of View
Boezaart Score
0
1
2
3
4
5
Description
No bleeding, virtually bloodless field
Slight bleeding, blood suctioning is not required
Mild bleeding, occasional suctioning without interference of surgical field
Moderate bleeding, suctioning is usually used; bleeding threatens surgical field but improves after suctioning
Heavy bleeding, suctioning is frequently used; bleeding threatens surgical field directly after suction is removed
Severe bleeding, bleeding appears faster than suctioning and is uncontrollable
Methods
A prospective, randomized controlled trial was conducted at
the St Paul’s Sinus Centre (SPSC) in Vancouver, Canada. This
trial was conducted with the approval of the University of
British Columbia Clinical Research Ethics Board. Patients
receiving FESS for chronic rhinosinusitis (CRS) with or without polyposis were consented for enrollment between
November 2011 and May 2012. Inclusion criteria were a diagnosis of CRS, based on the Canadian clinical practice guidelines for sinusitis15; age between 19 and 75 years; and an
American Society of Anesthesiologists (ASA) physical status
classification system score of less than III.16 Patients were
excluded if they had severe or uncontrolled hypertension and
cardiovascular disease, continued use of anticoagulants,
impaired coagulation, or a sinonasal tumor. Routine coagulation tests were not performed, but patients were asked about
personal history and family history of bleeding disorders. If a
history of bleeding problems was identified, a coagulation
screen was carried out. Patients with mild or moderate hypertension, diabetes, chronic renal disease, and other major uncritical medical conditions were included. As per standard
preoperative practice at the SPSC, all patients were treated
with a 1-week course of corticosteroids and oral antibiotics.
Anticoagulants and herbal medications were ceased 7 days
prior to surgery. Computer tomography (CT) imaging was
reviewed in axial, coronal, and sagittal planes and scored
according to the Lund-Mackay (LM) staging system.17 All
operations were performed by the 2 senior authors (IFH and
ARJ). The nose was prepared preoperatively using xylometazoline spray, and intraoperatively, neuropatties soaked with a
topical vasoconstrictor (xylomatazoline) were used in all cases.
Epinephrine injections and topical hemostatic agents (such as
Surgicel) were not routinely used.
Sixty-four patients were randomized by a closed-envelope
system to either the control (HP) or experimental (RTP)
group. All patients were first positioned in a 0-degree horizontal orientation, to allow anesthesia to be administered.
Patients in the HP group (32 patients) remained in this position for the duration of the surgery. Experimental study subjects were tilted to a 15-degree RTP (32 patients), according
to a magnetically attached protractor, accurate to 61 degree.
Experimental positions were verified at the operating table’s
fulcrum point and at the patient’s head. All patients received
general anesthetic, by a combination of intravenous and
inhaled agents. Anesthesia was induced with propofol according to the patient’s weight, preexisting health conditions, and
discretion of the attending anesthesiologist. Anesthesia was
maintained with inhaled desflurane and an intravenous infusion of remifentanil and propofol. This was the same for all
cases, and therefore there was no difference in anesthetic
technique between the 2 groups.
The primary outcome measures were the Boezaart scale
for surgical field,4 total blood loss (TBL), and blood loss
per minute (BL/min). The Boezaart score, systolic and diastolic blood pressure, and mean arterial blood pressure
(MABP) were recorded every 15 minutes. The total blood
loss and time of surgery were recorded at the completion of
surgery, and from this the blood loss per minute was calculated. Total blood loss was calculated by the circulating
nurse by subtracting the amount of irrigation used from the
total volume in the suction bottles. A second nurse always
corroborated the TBL calculation. The Boezaart scoring
system is a scale assigning a numerical value from 0 to 5, to
quantify the extent of endoscopic visual impairment from
intraoperative blood loss (Table 1).4 Mild bleeding requiring infrequent suctioning without interference in surgical
field is scored a lesser numerical value than extensive bleeding causing significant visual obstruction.
The Microdebrider (ENT RADenoid 3.5-mm Tricut
Blade; Medtronic, Minneapolis, Minnesota) was used in all
cases. Statistical analysis of data was conducted using
GraphPad Prism version 5.0a (GraphPad Software, La Jolla,
California). The independent Student t test was used to compare age, time of surgery, MABP, TBL, and BL/min between
the HP and RTP groups. The Mann-Whitney U test was used
to calculate the difference in LM score and Boezaart surgical
field of view between both groups. A P value of less than .05
was considered significant. Discussion with a statistician indicated that based on a previous study,8 a total sample size of
64 patients would be needed to achieve a statistical power of
80%. To determine the sample size, a confidence interval of
95% was used to create a responsive range of double the
standard deviation. In consideration of the location and vascularity of the paranasal sinuses, a Boezaart score of 3 was
expected during surgery. A clinically significant change in
intraoperative bleeding will be defined as a change in
Boezaart scoring by 20%, or 1 point in relation to the scale.
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Otolaryngology–Head and Neck Surgery 148(2)
Enrollment
Assessed for eligibility (n= 79)
Excluded (n=15)
♦ Not meeting inclusion criteria (n= 10)
♦ Declined to participate (n= 5)
♦ Other reasons (n= 0)
Randomized (n= 64)
Allocation
Allocated to RTP (n= 32)
♦ Received RTP (n= 32)
♦ Did not receive allocated intervention (n= 0)
Allocated to HP (n=32)
♦ Received HP (n= 32)
♦ Did not receive allocated intervention (n= 0)
Follow-Up
Lost to follow-up (n=0)
Lost to follow-up (n= 0)
Discontinued intervention (n= 0)
Discontinued intervention (n= 0)
Analysis
Analyzed (n= 32)
Analyzed (n= 32)
♦ Excluded from analysis (n= 0)
♦ Excluded from analysis (n= 0)
Figure 1. Flow diagram showing the pathway of participants through the randomized controlled trial. HP, horizontal position; RTP, reverse
Trendelenburg position.
Table 2. Characteristics of HP and RTP Groups
Characteristics
Age, y
Sex, No.
Male
Female
Polyposis, No.
CT score (Lund-Mackay system)
TOS, min
MABP, mm Hg
TBL, mL
BL/min, mL/min
Surgical field, Boezaart system
HP Group (n = 32)
RTP Group (n = 32)
50.06 6 11.69
52.13 6 10.59
15
17
6
10.94 6 6.85
94.38 6 34.87
68.57 6 7.34
426.3 6 333.0
4.26 6 2.44
2.33 6 0.67
14
18
10
13.06 6 7.61
87.47 6 35.94
68.83 6 10.71
247 6 198.2
2.68 6 1.62
1.66 6 0.55
P Value
.504 (NS)
1.000 (NS)
.387 (NS)
.283 (NS)
.434 (NS)
.910 (NS)
.01 (95% CI, 265.1-408.2)
.003 (95% CI, 2.918-4.021)
\.001 (95% CI, 1.822-2.169)
Values are presented as mean 6 SD unless otherwise indicated. Abbreviations: BL/min, blood loss per minute; CI, confidence interval; CT, computed tomography; HP, horizontal position; MABP, mean arterial blood pressure; NS, nonsignificant (P . .05); RTP, reverse Trendelenburg position; TOS, time of surgery;
TBL, total blood loss.
Results
Sixty-four patients were included and completed the study,
with a mean age of 58 years. There were 32 patients (15
men and 17 women) in the HP group and 32 patients (14
men and 18 women) in the RTP group (Figure 1).
Multiple variables were compared between the HP and
RTP arms, such as LM score, Boezaart surgical field score,
MABP, TBL, TOS, and BL/min (Table 2). Similar severity of disease was observed between the HP and RTP
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Hathorn et al
Table 3. Results of HP and RTP Groups for Cases with Polyposis
TBL, mL
BL/min, mL/min
Surgical field, Boezaart system
HP Group (n = 6)
RTP Group (n = 10)
P Value (95% CI)
750.0 6 186.2
6.475 6 1.274
2.859 6 0.6983
369.5 6 83.38
3.626 6 0.5426
2.009 6 0.5404
.05 (307.7-716.7)
.04 (3.158-6.239)
.05 (1.944-2.711)
Values are presented as mean 6 SD. Abbreviations: BL/min, blood loss per minute; HP, horizontal position; RTP, reverse Trendelenburg position; TBL, total
blood loss.
Table 4. Results for Those Patients with and without Polyps
Total Population (RTP and HP)
Polyps
No Polyps
P Value (95% CI)
n
TBL, mL
BL/min, mL/min
Surgical field, Boezaart system
16
512.2 6 383.7
4.698 6 2.891
2.327 6 0.7199
48
278.1 6 221.4
3.063 6 1.787
1.885 6 0.6553
.0038 (265.1-408.2)
.0255 (2.92-4.023)
.037 (1.82-2.169)
Values are presented as mean 6 SD unless otherwise indicated. Abbreviations: BL/min, blood loss per minute; HP, horizontal position; RTP, reverse
Trendelenburg position; TBL, total blood loss.
groups, as no significant difference was found when comparing respective LM score (P . .05). The RTP group
showed significantly reduced TBL (P = .01), BL/min (P =
.003), and Boezaart field of view (P \ .001). No significant difference was noted in TOS between the HP and
RTP groups (P . .05). Subanalysis comparing CRS with
or without polyps yielded similar results as found in the
study population as a whole. Polyposis was present in 6
(19%) patients in the HP group and 10 (31%) in the RTP
group. The RTP polyp group showed significantly reduced
TBL (P = .05), BL/min (P = .04), and Boezaart field of
view (P = .05) when compared with the HP polyp group
(Table 3). Chronic rhinosinusitis with polyposis showed a
significantly higher TBL (P = .0038), BL/min (P = .0255),
and Boezaart score (P = .037) compared with CRS without
polyps (Table 4). This was also the case within both the
RTP and HP groups. No adverse events were encountered
in any patients in the control or experimental surgical
positions.
Discussion
Functional endoscopic sinus surgery is the established surgical technique for the management of CRS with or without
polyposis. The surgery is performed within a small cavity,
and therefore even a small amount of bleeding can impair
the surgical field and the surgeon’s ability to visualize a
particular area. The sinonasal mucosa in CRS is often
severely inflamed and, in combination with a rich blood
supply, can result in rapid bleeding. This can prolong surgery and may increase the chance of complications.18 Major
complications such as cerebrospinal fluid leaks, orbital
damage, and carotid artery injury are rare in FESS, with figures of 0.5% to 2% quoted.19,20 A simple method to reduce
blood loss and improve surgical field is therefore welcome.
Many techniques have been used to achieve this goal, with
the most studied method being hypotensive anesthesia.
Reducing mean arterial pressure (MAP) excessively may
reduce cerebral perfusion and precipitate ischemia in ‘‘atrisk’’ patients. Increasing the concentration of the inhaled
volatile agent can induce hypotension, but this is associated
with peripheral vasodilation and rebound tachycardia that
may in fact increase bleeding.21 Many different hypotensive
agents have also been studied, including b-blockers,6,22 captopril,3 and sodium nitroprusside.4 There remains concern
with the use of hypotensive agents in those patients with
cardiovascular disease.6 Other studies have shown that
TIVA can improve surgical field and decrease blood loss
independent of any reduction of MAP.7,23,24 However, there
remains a need for a simple method to improve surgical
field during FESS, such as patient position.
Our study has confirmed that a 15-degree RTP significantly reduces TBL (P = .01), BL/min (P = .003), and surgical field (P \ .001) compared with HP. All other variables,
including MAP and Lund-Mackay score, showed no significant difference between the 2 groups. There was a trend
toward surgery in the RTP group taking less time, but this
was not statistically significant. The same anesthetic technique was used in all patients, and no epinephrine was
injected or used topically in any of the procedures.
Therefore, it seems that RTP significantly improves surgical
field and reduces blood loss. This supports the previous
findings by Ko et al.8 Their study showed a reduction in
blood loss and an improvement in surgical field with RTP.
However, the severity of disease in this population was relatively mild, and the anesthetic technique was not consistent
(both desflurane and sevoflurane were used randomly). The
investigators also injected lidocaine and epinephrine into the
operative field and pterygopalatine fossa in all patients, but
the volume given was not standardized—only an upper limit
of 10 mL was set. In our study, the anesthetic technique was
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Otolaryngology–Head and Neck Surgery 148(2)
standardized, and disease severity was much greater with
mean LM scores in the RTP group of 13.06 and in the HP
group of 10.94. The improvement in surgical field with RTP
therefore appears to be maintained even with severe disease.
Other studies have used RTP to reduce blood loss, but none
of them used RTP as a statistical variable.3,4 Our findings
also showed that bleeding and surgical field are worse in
CRS with polyps in either position, again confirming the previous studies in this area.7,8 This is due to the increased
inflammation and vascularity present in the mucosa in CRS
with polyps. However, it must be noted that stratification of
the patient sample into polyps and no polyps diminishes the
power of the hypothesis test. Another limitation of the study
is that the surgeon was obviously not blinded to the surgical
position of the patient. Attempts were made to try to negate
any possible bias in this regard by having 2 surgeons and a
third researcher attributing a Boezaart score every 15 minutes
and an average score recorded.
The reverse Trendelenburg position is thought to decrease
cardiac output and subsequently lower MAP. However, MAP
was not found to be significantly different between the 2
groups. Ko et al8 concluded that as there was no difference
in MAP between the 2 positions in their study, as was also
the case in our study, the reduction in venous return in the
RTP is the most likely mechanism that blood loss is reduced.
However, a study measuring nasal mucosal blood flow using
laser Doppler blood flowmetry showed that elevation of the
head by an angle of 20 degrees reduced nasal mucosal blood
flow by 38.3%.25 Therefore, the mechanism of reduced blood
loss in the RTP may be a combination of reduced venous
return and reduced arterial blood flow.
The reverse Trendelenburg position has been used
between 5 and 30 degrees.3,4,8,10-14 It has been shown to be
safe and effective in neurosurgery at reducing blood loss and
intracranial pressure without compromising cerebral perfusion
pressure.10,12-14 However, there remains a concern that in certain patients, prolonged RTP will reduce cerebral perfusion,
resulting in ischemia. Venous air embolism has also been
reported in a patient undergoing FESS for a tumor excision
in a head-up position.26 It is therefore important to place the
patient head up but not to such an extent as to cause complications. The 10- and 15-degree RTP are the only positions
specifically studied in FESS and have been shown to significantly improve surgical field and reduce blood loss. It would
therefore seem appropriate to place patients in at least 10
degrees RTP and no more than 15 degrees. Any further headup tilt would seem to be unnecessary. However, currently it
is not clear whether a 5-degree RTP would have the same
beneficial effect. The 5-degree RTP position has been used in
previous FESS research3,4; however, position was not a variable being studied, and 5 degrees was used arbitrarily by the
operating surgeon. This is something that would be useful to
study in the future. At 5 degrees, the potential risk of reduced
cerebral perfusion is lower, and if the positive results were
replicated, then this would be a more preferable position.
In conclusion, RTP has been shown to significantly
reduce TBL, BL/min, and surgical field in FESS. We would
therefore recommend RTP as a simple method to reduce
blood loss, improve surgical field and visualization, and
potentially reduce complications in FESS. It should be
noted that changing the patient position from HP to RTP
will alter hand-instrument angles. Therefore, a surgeon who
has always used the HP should be aware of the changes that
occur in these angles when initially adopting the RTP.
Acknowledgments
We authors thank Rachelle Moshfeghi, BSc, CCRP, for support
and guidance regarding the initial design of the study and subsequent ethics application.
Author Contributions
Iain F. Hathorn, design, data acquisition, data interpretation,
drafting/revising and approval of manuscript; Al-Rahim R. Habib,
design, data acquisition/analysis, drafting and approving manuscript; Jamil Manji, design, data acquisition/analysis, drafting and
approving manuscript; Amin R. Javer, design, data interpretation,
revising and approving manuscript.
Disclosures
Competing interests: None.
Sponsorships: None.
Funding source: None.
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