Transcutaneous near-infrared spectroscopy for detection of regional spinal
ischemia during intercostal artery ligation: Preliminary experimental results
Scott A. LeMaire, Lyssa N. Ochoa, Lori D. Conklin, Ron A. Widman, Fred J. Clubb,
Jr, Akif Ündar, Zachary C. Schmittling, Xing Li Wang, Charles D. Fraser, Jr and
Joseph S. Coselli
J Thorac Cardiovasc Surg 2006;132:1150-1155
DOI: 10.1016/j.jtcvs.2006.05.047
The online version of this article, along with updated information and services, is
located on the World Wide Web at:
http://jtcs.ctsnetjournals.org/cgi/content/full/132/5/1150
The Journal of Thoracic and Cardiovascular Surgery is the official publication of the American
Association for Thoracic Surgery and the Western Thoracic Surgical Association. Copyright ©
2006 American Association for Thoracic Surgery
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LeMaire et al
Transcutaneous near-infrared spectroscopy for detection of
regional spinal ischemia during intercostal artery ligation:
Preliminary experimental results
Scott A. LeMaire, MDa,d, Lyssa N. Ochoa, MDd, Lori D. Conklin, MDd, Ron A. Widmanf, Fred J. Clubb, Jr, DVM, PhDb,
Akif Ündar, PhDc,e, Zachary C. Schmittling, MDd, Xing Li Wang, MD, PhDd, Charles D. Fraser, Jr, MDa,e, and
Joseph S. Coselli, MDa,d
Objective: Real-time information about regional spinal cord ischemia can guide
intraoperative management and reduce the risk of paraplegia after thoracic aortic
surgery. We hypothesized that near-infrared spectroscopy could provide such information during intercostal and lumbar artery ligation in pigs.
Methods: Transcutaneous near-infrared spectroscopic sensors were placed in the
midline over the upper and lower thoracic vertebrae of 4 progressively larger pigs
(weight range 21-70 kg). After the entire aorta was exposed, segmental arteries from
T6 through L1 were sequentially ligated while regional oxygen saturation was
monitored. Decreases in regional oxygen saturation were calculated as percentage
changes from baseline. The degrees of ischemia in the upper and lower spinal cord
were compared histopathologically.
ET
From the Cardiovascular Surgery Service,a
Department of Cardiovascular Pathology,b
and Cullen Cardiovascular Surgical Research Laboratories,c Texas Heart Institute
at St Luke’s Episcopal Hospital, Houston,
Tex; the Divisions of Cardiothoracic Surgeryd and Congenital Heart Surgery,e Michael E. DeBakey Department of Surgery,
Baylor College of Medicine, Houston, Tex;
and the Somanetics Corporation, Troy,
Mich.f
Supported by the Michael E. DeBakey Department of Surgery Seed Fund and the
Somanetics Corporation, Troy, Mich.
R.A.W. is Vice President, Medical Affairs,
at Somanetics Corporation, the manufacturer of the device described in this report.
Received for publication March 8, 2006;
revisions received April 27, 2006; accepted
for publication May 8, 2006.
Address for reprints: Scott A. LeMaire,
MD, One Baylor Plaza, BCM 390, Houston, TX 77030 (E-mail: slemaire@bcm.
tmc.edu).
J Thorac Cardiovasc Surg 2006;132:1150-5
0022-5223/$32.00
Copyright © 2006 by The American Association for Thoracic Surgery
doi:10.1016/j.jtcvs.2006.05.047
1150
Results: Baseline regional oxygen saturations were similar in the upper (68.8% ⫾
9.0%) and lower (68.0% ⫾ 11.5%, P ⫽ .82) cord. After ligation, however, regional
oxygen saturation levels were significantly lower in the lower cord (41.3% ⫾
10.1%) than in the upper cord (64.8% ⫾ 9.3%, P ⫽ .037). The regional oxygen
saturation had decreased by 39.0% ⫾ 11.5% in the lower cord but only by 6.3% ⫾
7.6% in the upper cord (P ⫽ .026). This difference was confirmed microscopically:
upper-cord sections had fewer ischemic neurons (8.8 ⫾ 9.4) than did lower-cord
sections (21.3 ⫾ 13.6, P ⫽ .002).
Conclusion: Intraoperative spinal cord ischemia was detectable with near-infrared
spectroscopy in pigs weighing as much as 70 kg. The potential utility of this
technique in patients undergoing thoracic aortic surgery warrants investigation.
T
he inability to directly measure spinal cord blood flow and oxygenation
intraoperatively is a major obstacle to preventing paraplegia after thoracic
aortic surgery. Real-time information about spinal cord ischemia can guide
the adjustment of distal aortic perfusion pressure and the reattachment of intercostal
arteries.1
Current spinal cord monitoring techniques rely on somatosensory-evoked potentials (SSEPs) or motor-evoked potentials (MEPs). Monitoring SSEPs has several
disadvantages, including slow response time (caused by delays between the onset of
ischemia and the disappearance of potentials) and poor overall sensitivity and
specificity.2-4 Although MEP monitoring has been successfully used to detect spinal
cord ischemia, guide surgical strategy, and prevent postoperative neurologic deficits, it has limitations that have prevented it from being widely adopted.1,5-7
Transcutaneous near-infrared spectroscopy (NIRS), which exploits the unique
near-infrared absorption profiles of hemoglobin, oxyhemoglobin, and cytochrome
aa3, is currently widely used for cerebral oximetry during cardiovascular sur-
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LeMaire et al
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gery.8-12 This technique assesses the oxyhemoglobin fraction within a focal area of underlying tissue by measuring
the differential absorption of two wavelengths of nearinfrared light (730 and 810 nm) that reflect deoxyhemoglobin and total hemoglobin concentration. The purpose of this
pilot study was to assess the feasibility of using NIRS to
detect spinal cord ischemia during intercostal artery ligation
in the pig.
Materials and Methods
The protocol for this study was approved by the institutional
animal care and use committees of both Baylor College of Medicine and the Texas Heart Institute. The animals received humane
care and handling in compliance with the “Principles of Laboratory Animal Care” formulated by the National Society for Medical
Research and with the “Guide for the Care and Use of Laboratory
Animals” (http://www.nap.edu/catalog/5140.html).
Anesthetic Management
Four domestic swine (weighing 21, 37, 48, and 70 kg) were
premedicated with intramuscular atropine sulfate (0.5 mg/kg),
acepromazine maleate (0.1 mg/kg), and ketamine hydrochloride
(20 mg/kg). Isoflurane (0.5%-3.0%) was given by mask for induction. Crystalloid fluid was infused throughout the procedure, and
boluses of hetastarch were given when needed. Monitors included
a pulse oximeter placed on the ear, electrocardiographic leads, and
a rectal temperature probe. The animals were orally intubated with
a cuffed endotracheal tube through direct laryngoscopy and connected to a volume ventilator that delivered 100% oxygen at a tidal
volume of 10 mL/kg. General anesthesia was maintained with
inhaled isoflurane (0.5%-3.0%) and pancuronium bromide (0.1
mg/kg). A warming blanket was placed underneath the pigs to
maintain normothermia. A carotid artery catheter was used for
blood pressure monitoring and arterial blood gas sampling.
Operative Procedure
The dorsal area was shaved and cleaned, and 5100SAF SomaSensors (Somanetics Corporation, Troy, Mich) were placed in the
midline over the upper (T6-T7) and lower (T9-T11) thoracic
vertebrae. These sensors were connected to an INVOS 5100 Cerebral Oximeter (Somanetics Corporation). A pediatric spinal
drainage catheter was inserted into the subarachnoid space through
either a laminectomy or direct puncture between the third and
fourth lumbar vertebrae.
A left thoracoabdominal incision was made through the sixth
intercostal space. The diaphragm was divided, and the entire
thoracoabdominal aorta was exposed. Regional spinal oxygen sat-
uration (SrO2) was monitored continuously by both upper and
lower sensors. Raw optical data from the sensors were stored in a
computer at 4-second intervals. After baseline SrO2 levels were
recorded, segmental intercostal and lumbar arteries from T6
through L1 were sequentially occluded at approximately 10minute intervals. Each artery was initially occluded with a bulldog
clamp; after approximately 10 minutes of clamping, SrO2 was
recorded, and the artery was ligated with metallic clips and
divided.
After all segmental arteries were ligated, 1 mL indocyanine
green dye (2.5 mg/mL; Akorn, Inc, Buffalo Grove, Ill) was injected into the subarachnoid space through the spinal catheter. This
dye absorbs near-infrared light in a band centered at 805 nm. The
catheter was flushed twice with 1 mL saline solution to distribute
the dye evenly within the space surrounding the spinal cord.
Optical density (the log of the ratio of measured intensity to
incident intensity) at 810 nm was recorded with the oximeter to
determine changes in light absorption. After ligation of the L1
segmental arteries in each of the 3 largest pigs, the animals were
briefly awakened and examined for hind limb paralysis. After this
examination, the animals were reanesthetized and humanely killed
with intravenous potassium chloride.
Histopathology
The entire spinal column was removed from each of the 3 largest
pigs and placed in formalin after the upper and lower segments
monitored by the sensors were marked. Identification of the arteria
radicularis magna (Adamkiewicz artery) was not attempted. The
cords were sectioned, and representative portions of both regions
were stained with either hematoxylin and eosin or luxol fast blue
dye. A pathologist (F.J.C.) who was blind to the origin of each
section (upper or lower cord) examined the sections and quantified
ischemic change by counting the number of normal neurons and
the number of ischemic neurons per section.
Statistical Analysis
The statistical analyses were performed with SPSS version 12.0 for
Windows (SPSS Inc, Chicago, Ill). The following intraoperative
variables were compared: mean upper- and lower-cord SrO2 values
at baseline and after ligation of the segmental spinal arteries T6
through L1; absolute percentage SrO2 decline from baseline after
each vessel was ligated; and mean heart rate, temperature, and
mean arterial pressure. The upper and lower cords were compared
in terms of the number of ischemic neurons and the ratio of
ischemic to normal neurons. Continuous variables are reported as
mean ⫾ SD and were analyzed with the Student t test for betweengroup differences. We used analysis of variance for comparisons
among three or more groups. The Bonferroni correction was used
for multiple comparisons.
Results
Clinical
Mean physiologic parameters at baseline included heart rate
of 99.0 ⫾ 3.6 beats/min, mean arterial pressure of 55.3 ⫾
4.3 mm Hg, and rectal temperature of 36.1°C ⫾ 1.9°C.
These parameters remained stable throughout the procedures. Baseline SrO2 values were similar in the upper
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Abbreviations and Acronyms
MEP ⫽ motor-evoked potential
NIRS ⫽ near-infrared spectroscopy
SrO2 ⫽ regional spinal oxygen saturation
SSEP ⫽ somatosensory-evoked potential
TAAA ⫽ thoracoabdominal aortic aneurysm
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LeMaire et al
Figure 1. Graph showing percentage decline from baseline
(mean ⴞ SD) in SrO2 (rSO2) at T6-7 and T9-11 vertebral levels
during sequential ligation of intercostal arteries. Once all vessels
were ligated, decrease in SrO2 detected by lower sensor was
significantly greater than that detected by upper sensor (P ⴝ
.026).
ET
(68.8% ⫾ 9.0%) and lower (68.0% ⫾ 11.5%) cord segments (P ⫽ .82). Upper-cord SrO2 remained stable throughout the procedure, whereas lower-cord SrO2 began to decrease after the T9 segmental artery was ligated. This
decline continued after ligation of the T10 and T11 vessels
and became statistically significant after ligation of T12 and
L1. Most of the declines in SrO2 began within 1 minute of
arterial ligation. After all segmental arteries were ligated,
mean SrO2 levels were 64.8% ⫾ 9.3% in the upper cord and
41.3% ⫾ 10.1% in the lower cord (P ⫽ .037); the percentage reduction in SrO2 from baseline was much larger in the
lower cord (39.0% ⫾ 11.5%) than in the upper cord (6.3%
⫾ 7.6%, P ⫽ .026; Figure 1).
Subarachnoid injection of indocyanine green dye increased near-infrared light absorption at 810 nm (Figure 2)
in all the pigs, indicating that a portion of the NIRS photons
penetrated the tissues to the depth of the spinal cord. After
injection of the dye, reductions in optical density (relative to
baseline) for the 4 pigs were 12.3%, 20.7%, 33.1%, and
21.2% (mean 21.8% ⫾ 8.6%).
Lower spinal cord ischemia was also confirmed by physical examination. Three pigs were briefly awakened and
examined after the operation, and paralysis of the hind limbs
without involvement of the upper limbs was present in each.
Histopathology
The regional difference in the degree of ischemia was
confirmed by microscopic examination of the lateral corticospinal tracts. Lower-cord sections exhibited more pronounced ischemic changes than did upper-cord sections,
including increased vacuolization, retraction of neurons,
and loss of nucleoli (Figure 3). Lower-cord sections also
1152
Figure 2. Representative graph showing increase in near-infrared light absorption at 810 nm after subarachnoid injection of
indocyanine green dye (ICG).
had more ischemic neurons (mean 21.3 ⫾ 13.6 per section)
than did upper-cord sections (mean 8.8 ⫾ 9.4 per section, P
⫽ .002). These numbers corresponded to a significantly
lower ratio of ischemic to normal neurons in the upper cord
(0.17) than in the lower cord (0.50, P ⫽ .005), indicating
that the regional differences in spinal ischemia indicated by
the NIRS monitor paralleled the regional histopathologic
differences.
Discussion
Despite the use of numerous protective adjuncts during
thoracoabdominal aortic surgery, spinal cord ischemic injury leading to paraplegia or paraparesis continues to be a
significant problem. We recently reviewed contemporary
reports of patients who underwent extensive thoracoabdominal aortic aneurysm (TAAA) repairs and found that
neurologic deficits occurred in as many as 32% of patients.13 These neurologic deficits may contribute to mortality; in Svensson and colleagues’ analysis14 of a series of
TAAA repairs in 1509 patients, those who had paraplegia or
paraparesis had a significantly lower 5-year survival (only
44%) than did patients without deficits (62%, P ⬍ .0001).
The risks of paraplegia and paraplegia-related death after
descending thoracic aortic aneurysm and TAAA repair
might be reduced if spinal cord perfusion and oxygenation
could be monitored directly during surgery.
Attempts to monitor spinal cord perfusion indirectly during aortic aneurysm surgery began with the monitoring of
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Figure 3. Representative histologic lateral corticospinal tract sections from upper (A, C, E) and lower (B, D, E)
spinal cord. Compared with proximal sections, distal sections exhibited more pronounced ischemic changes,
including increased vacuolization (arrowheads), retraction of neurons (arrows), and loss of nucleoli (double
arrows). (Hematoxylin-eosin [A, B] and Luxol fast blue [C-F] staining; original magnifications ⴛ20 [A-D] and ⴛ40
[E, F]).
SSEPs, measurable electrical patterns that occur within the
spinal cord when a peripheral sensory nerve (usually the
posterior tibial nerve) is stimulated.15 Although SSEP monitoring showed promise in canine studies,16 a clinical trial
by Crawford and associates2 showed that the measurement
of SSEPs during aortic surgery did not reduce the incidence
of postoperative neurologic deficits.17 The poor sensitivity
and specificity of SSEP monitoring is partially attributable
to the fact that the sensory and motor pathways of the spinal
cord are anatomically separate and have different blood
supplies. The amplitude of SSEPs only indicates the function of sensory tracts, which are located in the dorsal portion
of the spinal cord and are not supplied by the anterior spinal
artery, where blood flow is reduced during aortic clamping.
As a result, SSEP monitoring provides only delayed information about spinal cord ischemia.18
In contrast, MEPs reflect the functional integrity of the
motor pathways in the anterior (ventral) cord, especially the
more vulnerable motor neurons in the anterior gray matter.
Because the anterior cord is supplied by the anterior spinal
artery, MEP monitoring is an anatomically and physiologically sound means of detecting spinal ischemia during
aortic clamping. Jacobs and colleagues1,5-7 have used MEP
monitoring as part of their spinal cord protection strategy
and have achieved excellent results. In a pilot study involving 52 consecutive patients with Crawford extent I or II
TAAAs, Jacobs and colleagues1 recorded MEPs in all patients and reported that spinal cord ischemia was detected as
early as 2 minutes after intercostal artery ligation. During
distal aortic perfusion, 14 patients showed a rapid decrease
in MEP amplitude to less than 25% of baseline, indicating
spinal cord ischemia; this was corrected by increasing distal
aortic pressure. Additionally, in 33 patients, aggressive reattachment of intercostal arteries returned MEP amplitudes
to baseline levels, and no early or late paraplegia occurred.
Jacobs and Mess5 recently reported preventing neurologic
deficits in 98% of patients undergoing TAAA repair by
using MEP monitoring.
MEP monitoring is not, however, without limitations.19,20 For example, the neuromuscular blocking agents
that are part of the usual anesthetic regimen interfere with
MEP monitoring. For this reason, MEP monitoring requires
alterations in standard anesthetic management to prevent
complete neuromuscular blockage. Also, MEP monitoring
depends on signal averaging across a span of seconds,
which limits its ability to detect vascular compromise before
neurons have been irreversibly injured. Additional limitations of this technique include the need for monitoring by a
neurophysiologist during the operation and its inability to be
used in conscious postoperative patients. For these reasons,
although MEP monitoring has been shown to reduce the risk
of paraplegia, the technique is not widely used.
Other methods of monitoring spinal cord ischemia currently being studied include intrathecal monitoring of cerebrospinal fluid oxygen tension21,22 and transesophageal
NIRS monitoring of spinal cord Sro2.23 An ideal spinal cord
monitoring method would (1) be noninvasive, (2) be simple
enough to use that no additional personnel are required, (3)
be highly sensitive and specific to changes in the anterior
spinal cord, (4) allow standard anesthesia delivery, (5) ex-
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hibit no delay in ischemia detection, and (6) be usable in
conscious postoperative patients. Transcutaneous NIRS has
the potential to satisfy these criteria.
Our pilot study was designed to assess the potential
usefulness of transcutaneous NIRS as a noninvasive monitor that provides continuous, real-time information about
spinal cord oxygenation. NIRS uses transcutaneous sensors
to measure the focal oxyhemoglobin fraction in underlying
tissue. Currently, this technique is used to monitor cerebral
oxygenation during a wide variety of cardiovascular operations.4,9,10,12,24 In addition to being entirely noninvasive,
the NIRS monitor is simple to use, requires no additional
technical personnel, and does not require modifications to
anesthetic management. In our experiment, we showed that
transcutaneous NIRS can detect intraoperative spinal cord
ischemia in a porcine model.
An initial concern was that the sensors would detect
oxygenation levels in the surrounding tissues, such as muscle and subcutaneous tissue, but not in the underlying spinal
cord. Given the anatomy of the blood supply shared between the spinal cord and these surrounding tissues, however, NIRS data on regional oxygenation may adequately
reflect spinal cord perfusion, albeit indirectly. To address
this issue specifically, we injected indocyanine green dye
into the subarachnoid space and found an immediate change
in light absorption (Figure 2), suggesting that at least some
of the photons were reaching the spinal cord. Additionally,
Macnab and coworkers25 found that, in a porcine model of
spinal cord hypoxia-ischemia, NIRS detected ischemic
changes in the spinal cord whether the sensors were placed
directly on the spinal cord, the spinal lamina, or the spinous
processes. Further experiments correlating direct measurements of spinal oxygenation with transcutaneous NIRS
readings would help clarify this issue.
Real-time information about spinal cord perfusion during
TAAA repair would allow the surgical team to intervene
when ischemia occurs. Intervention strategies used during
SrO2 monitoring could be based on those outlined in Jacobs
and colleagues’ report1 regarding MEP monitoring during
TAAA surgery. For example, when ischemia is detected, the
mean arterial pressure could be immediately increased. Distal aortic flow and pressure could also be increased when
left heart bypass is being used. Additionally, temporary
occlusion catheters could be placed in segmental arteries
with significant back-bleeding, thereby reducing steal from
the anterior spinal artery. Finally, decline in SrO2 could
prompt the reattachment of specific segmental arteries
within the isolated aortic segment, and aortic endarterectomy could be performed when segmental arteries are not
readily apparent.
Because of its potential value in guiding these types of
interventions, NIRS monitoring of spinal cord oxygenation
during thoracic aortic surgery is worthy of clinical investi1154
LeMaire et al
gation. Expanding the application of NIRS to postoperative
spinal cord monitoring as a means of preventing delayedonset paraplegia also merits study.
We gratefully acknowledge Paul Holman, MD, Jean-Paul Wolinsky, MD, Jamie Junkerman, and Gobind Anand for intraoperative assistance; and the staff at the Cullen Cardiovascular Research
Laboratory of the Texas Heart Institute— especially Kathleen
McKay, Blake Deady, and Amy Porter—for excellent anesthetic
management. Stephen N. Palmer, PhD, ELS, provided editorial
assistance, and Scott Weldon, MA, provided assistance with illustrations.
References
1. Jacobs MJ, Meylaerts SA, de Haan P, de Mol BA, Kalkman CJ.
Strategies to prevent neurologic deficit based on motor-evoked potentials in type I and II thoracoabdominal aortic aneurysm repair. J Vasc
Surg. 1999;29:48-57.
2. Crawford ES, Mizrahi EM, Hess KR, Coselli JS, Safi HJ, Patel VM.
The impact of distal aortic perfusion and somatosensory evoked potential monitoring on prevention of paraplegia after aortic aneurysm
operation. J Thorac Cardiovasc Surg. 1988;95:357-67.
3. Schepens MA, Boezeman EH, Hamerlijnck RP, ter Beek H, Vermeulen FE. Somatosensory evoked potentials during exclusion and
reperfusion of critical aortic segments in thoracoabdominal aortic
aneurysm surgery. J Card Surg. 1994;9:692-702.
4. Reuter DG, Tacker WA Jr, Badylak SF, Voorhees WD 3rd, Konrad
PE. Correlation of motor-evoked potential response to ischemic spinal
cord damage. J Thorac Cardiovasc Surg. 1992;104:262-72.
5. Jacobs MJ, Mess WH. The role of evoked potential monitoring in
operative management of type I and type II thoracoabdominal aortic
aneurysms. Semin Thorac Cardiovasc Surg. 2003;15:353-64.
6. Jacobs MJ, Elenbaas TW, Schurink GW, Mess WH, Mochtar B.
Assessment of spinal cord integrity during thoracoabdominal aortic
aneurysm repair. Ann Thorac Surg. 2002;74:S1864-6.
7. Jacobs MJ, Meylaerts SA, de Haan P, de Mol BA, Kalkman CJ.
Assessment of spinal cord ischemia by means of evoked potential
monitoring during thoracoabdominal aortic surgery. Semin Vasc Surg.
2000;13:299-307.
8. Edmonds HL Jr, Rodriguez RA, Audenaert SM, Austin EH 3rd,
Pollock SB Jr, Ganzel BL. The role of neuromonitoring in cardiovascular surgery. J Cardiothorac Vasc Anesth. 1996;10:15-23.
9. Cho H, Nemoto EM, Yonas H, Balzer J, Sclabassi RJ. Cerebral
monitoring by means of oximetry and somatosensory evoked potentials during carotid endarterectomy. J Neurosurg. 1998;89:533-8.
10. Daubeney PE, Smith DC, Pilkington SN, Lamb RK, Monro JL, Tsang
VT, et al. Cerebral oxygenation during paediatric cardiac surgery:
identification of vulnerable periods using near infrared spectroscopy.
Eur J Cardiothorac Surg. 1998;13:370-7.
11. Deeb GM, Jenkins E, Bolling SF, Brunsting LA, Williams DM, Quint
LE, et al. Retrograde cerebral perfusion during hypothermic circulatory arrest reduces neurologic morbidity. J Thorac Cardiovasc Surg.
1995;109:259-68.
12. Murkin JM. Perioperative detection of brain oxygenation and clinical
outcomes in cardiac surgery. Semin Cardiothorac Vasc Anesth. 2004;
8:13-4.
13. Coselli JS, LeMaire SA, Conklin LD, Köksoy C, Schmittling ZC.
Morbidity and mortality after extent II thoracoabdominal aortic aneurysm repair. Ann Thorac Surg. 2002;73:1107-15.
14. Svensson LG, Crawford ES, Hess KR, Coselli JS, Safi HJ. Experience
with 1509 patients undergoing thoracoabdominal aortic operations. J
Vasc Surg. 1993;17:357-68.
15. de Mol BA, Boezeman EH, Hamerlijnck RP, de Geest R. Experimental
and clinical use of somatosensory evoked potentials in surgery of
aneurysms of the descending thoracic aorta. Thorac Cardiovasc Surg.
1990;38:146-50.
16. Grabitz K, Freye E, Sandmann W. Somatosensory evoked potential,
a prognostic tool for the recovery of motor function following
The Journal of Thoracic and Cardiovascular Surgery ● November 2006
Downloaded from jtcs.ctsnetjournals.org on June 4, 2013
LeMaire et al
18.
19.
20.
malperfusion of the spinal cord: studies in dogs. J Clin Monit.
1993;9:191-5.
Mizrahi EM, Crawford ES. Somatosensory evoked potentials during
reversible spinal cord ischemia in man. Electroencephalogr Clin Neurophysiol. 1984;58:120-6.
Meylaerts SA, Jacobs MJ, van Iterson V, De Haan P, Kalkman CJ.
Comparison of transcranial motor evoked potentials and somatosensory evoked potentials during thoracoabdominal aortic aneurysm repair. Ann Surg. 1999;230:742-9.
van Dongen EP, Schepens MA, Morshuis WJ, ter Beek HT, Aarts LP,
de Boer A, et al. Thoracic and thoracoabdominal aortic aneurysm
repair: use of evoked potential monitoring in 118 patients. J Vasc Surg.
2001;34:1035-40.
Guerit JM, Dion RA. State-of-the-art of neuromonitoring for prevention of immediate and delayed paraplegia in thoracic and thoracoabdominal aorta surgery. Ann Thorac Surg. 2002;74:S1867-9; discussion
S1892-8.
21. Lips J, de Haan P, Bouma GJ, Holman R, van Dongen E, Kalkman CJ.
Continuous monitoring of cerebrospinal fluid oxygen tension in relation to motor evoked potentials during spinal cord ischemia in pigs.
Anesthesiology. 2005;102:340-5.
22. Christiansson L, Karacagil S, Thelin S, Hellberg A, Tyden H, Wiklund
L, et al. Continuous monitoring of intrathecal pO2, pCO2 and pH during
surgical replacement of type II thoracoabdominal aortic aneurysm. Eur
J Vasc Endovasc Surg. 1998;15:78-81.
23. Kunihara T, Shiiya N, Matsui Y, Yasuda K. Preliminary report
of transesophageal monitoring of spinal cord ischemia using nearinfrared spectrophotometry. J Cardiovasc Surg (Torino). 2004;45:
95-6.
24. Murkin JM. Etiology and incidence of brain dysfunction after cardiac
surgery. J Cardiothorac Vasc Anesth. 1999;13:12-7.
25. Macnab AJ, Gagnon RE, Gagnon FA. Near infrared spectroscopy
for intraoperative monitoring of the spinal cord. Spine. 2002;27:
17-20.
ET
17.
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1155
Transcutaneous near-infrared spectroscopy for detection of regional spinal
ischemia during intercostal artery ligation: Preliminary experimental results
Scott A. LeMaire, Lyssa N. Ochoa, Lori D. Conklin, Ron A. Widman, Fred J. Clubb,
Jr, Akif Ündar, Zachary C. Schmittling, Xing Li Wang, Charles D. Fraser, Jr and
Joseph S. Coselli
J Thorac Cardiovasc Surg 2006;132:1150-1155
DOI: 10.1016/j.jtcvs.2006.05.047
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