Intraoperative Spinal Cord Monitoring Patients undergoing corrective surgery for deformity are at a higher risk of spinal cord injury.. If the limbs, brain or spinal cord become cooler d
Trang 1ing this approach Blood collected in the drains within the first 2 – 4
postopera-tive hours can also be processed and reinfused with the cell saver system
Pharmacological Measures
Tranexamic acid or aprotinin [81] used with the induction of anesthesia has been
reported both in adults and children to reduce blood losses in spinal procedures
Because of its price (1 g tranexamic acid costs C$19.35 vs C$210 per allogenic
blood unit vs C$338 per autologous blood unit vs C$344.40 per vial of 500 000 U
of aprotinin), good tolerance and effectiveness, we and others [54, 65] prefer
tra-nexamic acid in a protocol of 15 – 50 mg/kg in a bolus with the induction of
anes-thesia plus an infusion of 1 g/h or boluses of 10 – 25 mg/kg every 3 h
intraoperati-vely and then q8 h for the first 24 h postoperatiintraoperati-vely An increase in coagulability,
changes in kaolin/Celite times or severe allergic reactions associated with the use
of aprotinin have not been reported with tranexamic acid [26] Recently, the use
of aprotinin was associated with a doubling of the risk of renal failure, a 55 %
increased risk of myocardial infarction and a 181 % increase in the risk of stroke
in cardiac surgery when compared to tranexamic acid [45] Desmopressin has
not proven useful in decreasing blood losses [76] in idiopathic scoliosis surgery
Anemia/hemodilution and low CHA increase the risk of ION
We do not use hemodilution since there is no demonstrated advantage of
add-ing it to patients havadd-ing CHA and antifibrinolytics More importantly, ION seems
to be much more likely to occur when combining anemia (or hemodilution) and
low CHA
Blood Transfusion and Coagulation Factor Substitution
The question of when to start transfusing blood products in spine surgery boils
down to what are the thresholds for the red cells (RBCs), platelets, plasma and
factors Blood is separated in blood banks into its components to optimize the
use of resources by allowing blood subproducts to be transfused in different
patients Two different approaches to blood component replacement have been
recommended The first is to transfuse fresh frozen plasma (FFP) and platelets
prophylactically after a certain number of units of RBCs have been transfused
However, there is no agreement on the optimal ratios; these vary widely, ranging
from 1 : 10 to 2 : 3 for FFP:RBCs and from 6 : 10 to 12 : 10 for platelets : RBCs The
second approach is to transfuse FFP, platelets or cryoprecipitate only when there
is clinical or laboratory evidence of coagulopathy; for instance, when there is
microvascular bleeding, a prothrombin time (PT) or a partial thromboplastin
time (PTT) > 1.5 times the normal value, thrombocytopenia with a platelet count
< 50 000 – 100 000/l or a fibrinogen concentration < 100 mg %
The following are recommendations from international publications
summa-rized by Leal-Noval [42] and the American Society of Anesthesiologist Task
Force on Perioperative Blood Transfusions 2005 (www.asahq.org)
RBC Concentrates Transfusion Criteria
) Hb < 8 g %
Note: 10 ml/kg of RBC
concentrate will increase the Hb by 1 – 2 g % or
3 – 6 points of hematocrit
) Hb between 8 and 10 g % in normovolemic patients, but with clinical signs
of myocardial, cerebral, or respiratory dysfunction; and
) intraoperative hemorrhage, i.e., bleeding of 10 ml/kg in the first hour or
5 ml/kg × h in the first 3 h (averaged)
Trang 2FFP Transfusion Criteria
Patients with active bleeding and:
Each unit of FFP contains
2 – 4 mg of fibrinogen/ml;
therefore each FFP unit
delivers the equivalent of
2 units of cryoprecipitate
) PT or PTT 1.5 times that of control subjects; International Normalized Ratio (INR) > 2.0
) massive transfusion of RBC concentrates > 30 ml/kg of packed red cells
) previous treatment with coumadin derivatives and unscheduled surgery (to give FFP 5 – 8 ml/kg)
) correction of factor deficiencies when specific factors are unavailable (to give FFP 10 – 15 ml/kg)
) heparin resistance (antithrombin III deficit)
Platelet Transfusion Criteria
Patients with severe hemorrhaging and:
) diffuse bleeding suggestive of platelet dysfunction
) platelet count < 50 000 – 100 000/l
) massive transfusion of RBC concentrates
) normal platelet count and platelet dysfunction (antiplatelet agents, throm-basthenia, uremia, etc.)
Cryoprecipitate and Factor Transfusion Criteria
) patients with active bleeding and fibrinogen < 80 mg %
) bleeding patients with von Willebrand’s disease in absence of specific con-centrates
Note: Each unit of cryoprecipitate contains 150 – 250 mg of fibrinogen The
start-ing dose is 1 unit for 10 kg body weight to increase fibrinogen level by 50 mg % (the hemostatic level is around 100 mg %) Cryoprecipitate does not contain Fac-tor V Therefore, it should not be the sole replacement therapy for disseminated intravascular coagulopathy (DIC), which is almost always associated with a
vari-ety of factor deficiencies and thrombocytopenia Intermediate purity Factor VIII concentrates are preferred for von Willebrand’s disease and recombinant or highly purified Factor VIII concentrate for hemophilia A because of its greater
efficacy and safety The intermediate purity concentrate contains significant therapeutic quantities of the von Willebrand’s component of Factor VIII, whereas the high purity preparations contain principally the hemophilia A com-ponent of Factor VIII
Transfusion Criteria for rFVIIa
rFVIIa is approved in many countries for patients with hemophilia and inhibitors (antibodies) to coagulation factors VIII or IX High circulating concentrations of FVIIa, achieved by exogenous administration, initiate hemostasis by combining with tissue factor at the site of injury, producing thrombin, activating platelets and coagulation factors II, IX and X, thus providing for the full thrombin burst that is essential for hemostasis This “bypass” therapy has led some clinicians to use rFVIIa “off-label” for disorders of hemostasis other than hemophilia The Israeli Multidisciplinary rFVIIa Task Force published their guidelines for its use
in uncontrolled bleeding [47], which recommended that optimal conditions (fibrinogen concentration > 50 mg %, platelet count > 50 000/l, pH > 7.2) should
be achieved before the administration of rFVIIa There are no clear recom-mended doses yet for rFVIIa A wide range of between 50 and 200 μg/kg has been
Trang 3advocated Because of its clearance (35 ml/kg/h), it is suggested to repeat the dose
every 2 h in case of persistent hemorrhage [82]
Massive transfusion can be defined as the acute replacement of more than one
blood volume within 6 h In previously healthy adults, coagulation defects
develop primarily from dilution of protein coagulation factors and platelets
when crystalloid, colloid and RBCs are used to replace lost volume
Coagulopa-thy associated with massive transfusion is clinically characterized by the
pres-ence of microvascular bleeding or oozing from the mucosae, wound and
punc-ture sites The development of acidosis, DIC, hypothermia and, rarely, a
hemo-Massive transfusions may result in acidosis, DIC, hypothermia and hemolytic transfusion reactions
lytic transfusion reaction may accompany massive transfusion and complicate
the ability to diagnose the coagulopathy While thrombocytopenia may develop
in massively transfused patients, administration of platelets should be reserved
for the patient exhibiting microvascular bleeding and a platelet count of less than
50 000/l In the massively transfused patient, clinical bleeding associated with
coagulation factor deficiencies is unlikely until factor activity levels fall below
20 % of normal This usually does not occur until greater than one blood volume
has been replaced FFP may be administered for correction of microvascular
bleeding in patients transfused with more than one blood volume PT and PTT
along with platelet count and fibrinogen level should guide the use of component
therapy Whole blood clotting analysis, as seen with thromboelastography,
pro-vides a dynamic picture of the entire clotting process Some potential metabolic
problems resulting from blood transfusion are hyperkalemia, hypocalcemia,
cit-rate toxicity, hypomagnesemia, acidosis and impaired oxygen-carrying capacity
of hemoglobin The electrocardiogram should be monitored in all patients for
signs of electrolyte abnormality during rapid infusions Hyperkalemia
exacer-bates the cardiovascular effects of hypocalcemia Administration of calcium
rap-idly antagonizes hyperkalemia by promoting transfer of potassium into the cells.
Intraoperative Spinal Cord Monitoring
Patients undergoing corrective surgery for deformity are at a higher risk of spinal
cord injury Similarly, patients who have sustained an incomplete traumatic
spi-nal cord injury are at risk of further damage Neurological deterioration can
occur because of ischemia of the neural structures secondary to mechanical
com-pression and/or vascular stretching Monitoring must be performed by an expe- Spinal cord monitoring
requires clinical practice for its effective use
rienced team and the surgeon must be interested in acting on the findings [18]
Teamwork and communication between the electrophysiology technician,
anes-thesiologist and surgeon are necessary to make spinal cord monitoring useful for
the patient Important facts regarding anesthesia stability and depth,
hemody-namics, blood volume, blood flow autoregulation of the spinal cord and
tempera-ture must be considered MAP below 60 mm Hg or hypovolemia can result in
sig-nificant changes in SSEPs [55, 57] During surgery, a MAP of 60 – 65 mm Hg is
usually maintained to reduce blood loss Drops in temperature can affect SSEP
waveforms [46] If the limbs, brain or spinal cord become cooler during surgery,
SSEP latencies will increase without an actual injury to the neural pathway The
anesthesia goals to facilitate neuromonitoring are highlighted inTable 4 An
elec-Table 4 Goals of anesthesia management to facilitate neuromonitoring
) tight and stable hypotensive blood pressure control ) normal end tidal CO2
) stable depth of anesthesia compatible with neuromonitoring ) Hb level above 7 g %
Trang 4tric line interference of 60 Hz coming from the operating room table or other electric equipment may severely affect the SSEP recordings [56]
In the presence of intraoperative spinal cord monitoring (IOM), neurological deficits after spine surgery relate to [56]:
) type of procedure
) the surgeon’s experience of spine surgery
) the surgeon’s experience using SSEP
) the technician’s experience (experience with less than 100 cases doubled the deficits compared with > 300 cases)
) Low (or narrower) cut filtering (30 Hz to 1 kHz) is better than 1 Hz to
5 kHz)
Anesthetic Effects on SSEPs
Intravenous opiates
may increase the latency
of SSEPs
Halogenated anesthetics produce a dose-related reduction in amplitude and an increase in the latency of responses to SSEPs [69] Nitrous oxide adds more
intense changes in cortical SSEP recording than those of halogenated drugs and
in fact they are synergic with isoflurane when used together Sevoflurane, desflu-rane or mixtures of N2O opiates may be used during SSEP monitoring as long as
the concentration of the inhaled agents is kept low (below 0.7 MAC) and stable to
avoid artificial effects due to changes in depth of anesthesia Subcortical record-ings (from C2) are relatively resistant to the depressing effects seen when cortical level recordings are made Cortical evoked potential (CEP) changes related to deepening anesthesia may be indistinguishable from spinal cord injury For this reason, subcortically generated SSEP recordings should be obtained to corrobo-rate CEP changes, while peripheral nerve responses should be recorded to ensure that the adequacy of stimulation has not changed to account for the CEP change Intravenous opiates used with inhaled agents in clinical anesthesia produce little impact on the amplitude of EEG; however, they may increase the latency of SSEPs This small effect of the systemic opiates on latency recordings seems to be μ-receptor dependent and occurs at a supraspinal level since spinal/epidurally administered morphine or fentanyl minimally affects SSEPs [67] Ketamine is an NMDA antagonist, which has become more popular lately as part of a multi-modal anesthetic approach Ketamine is known to increase amplitude responses
in cortical SSEPs as well as spinal and muscle recordings after spinal activation [39] Nonetheless, ketamine could be a problem when a WUT is required A simi-lar observation about SSEPs has been made with etomidate [37] Thiopental is a barbiturate and poses no problems for monitoring neurological parameters dur-ing spine surgery after the rapid redistribution of the sdur-ingle induction dose Short-acting benzodiazepines are combined with opiates or ketamine as part of
a balanced technique Induction and maintenance of anesthesia with midazolam induces negligible changes to cortical SSEP recordings [66] Combinations of midazolam-fentanyl and midazolam-ketamine along with N2O have been found equally appropriate in spine surgery and SSEP recording [39] Propofol is dependable for both the induction and maintenance of anesthesia with a very predictable pharmacodynamic response when used with target controlled infu-sions (TCIs) Propofol slightly depresses the amplitude of SSEPs at the brain cor-tex level with negligible action at clinical doses on spinal cord physiology Propo-fol is regarded as a very good alternative for anesthesia during functional moni-toring in spine surgery [69] Muscle relaxants do not affect SSEPs and in fact they might enhance the SSEP signal by decreasing electric noise by eliminating mus-cle artifacts Epidural/intrathecal, but not i.v., local anesthetics increase SSEP latency and are contraindicated because of their direct effect in spinal cord con-duction [36]
Trang 5Red Flags in SSEP Recordings
SSEP recordings can be affected in two dimensions: amplitude and/or latency A
50 % decrease in amplitude and/or a 10 % or 2-ms increase in latency in a
hemo-dynamically stable, normothermic patient are considered as indicators of spinal
cord insult [56] In this case, counteractive measures encompass surgical and
anesthetic reactions (seeTable 5) Changes in recordings that do not reverse to
normal after corrective measures and are still present at the end of the procedure
correlate with new postoperative nerve deficits [72]
Table 5 Course of action suggested for deteriorating neuromonitoring
Surgical interventions Anesthetic interventions
) reduction of correction ) increase in blood pressure
) removal of implant ) correction of anemia
) correction of hypovolemia ) normalization of temperature ) lighter anesthesia level ) IV steroids
) normalization of CO2
Anesthetic Effects on MEPs
MEPs are obtained by transcranial electrical (tcEMEP) or magnetic (tcMMEP)
stimulation of the motor cortex and recordings are made in muscles or
periph-eral nerves Stimulation can also be made at a high epidural level next to the
spi-nal cord In patients with spispi-nal cord deficits, MEPs can be present when SSEPs
are absent and vice versa Repetitive transcranial stimulation (trains of three to
five impulses as opposed to a single stimulus) can overcome some of the
depres-sant actions of anesthetics by temporal summation of the descending input on
the motoneurons MEP changes during spine surgery correlate well with
neuro-logical outcome MEPs are complementary to SSEPs in reducing spinal cord risk
MEP changes predict neurological outcome
of damage in complex spinal surgery tcMMEP seems to be more affected by
anesthetics than tcEMEP [69] MEPs may allow adequate recordings of patients
who are otherwise “unmonitorable” by SSEPs MEP signals should have an
amplitude of at least 50 μV before they are considered to be “monitorable.”
Keta-mine based anesthesia allows for appropriate MEP recording because of its
mini-mal depressing actions Barbiturates must be avoided if early recording of
tcMMEPs is required because up to 45 min of deep depression has been reported
[21] Midazolam and thiopental share the same depressing effect on tcMMEPs, so
these agents are not recommended when that kind of monitoring is to be used
[31] Complete motor blockade will prevent muscle response and recording of
cranial or spinal cord induced MEPs Partial neuromuscular blockade with
con-tinuous and stable infusions of muscle relaxants to keep a train-of-four of 3/4 has
been successfully reported [38] Constant evaluation with nerve stimulators or
closed-loop systems might produce a level of relaxation compatible with optimal
recording of MEPs and very good surgical conditions These evoked potentials
are large responses clear of signal averaging that can provide the surgeon with
good feedback MEPs may be contaminated by sudden patient movement and
anesthetic agents
Trang 6Red Flags in MEP Recordings
A rapid and permanent decrease in signal amplitude larger than 50 %, or a 100 V increase in the threshold of the MEP muscle response, is indicative of a neural compromise [50, 84] with potential neurological consequences
Nerve Root Monitoring
SSEPs and MEPs are less likely to alert the surgeon about single root potential damage than techniques monitoring that particular root Electrical stimulation
of screws placed in the pedicles can confirm correct placement or signal a breach
in the bone cortex by lowering the current needed to activate a sustained neuro-tonic electromyogram (EMG) discharge from the muscles innervated by that root [13] Some consider there is a malpositioned screw when a recording of com-pound muscle action potential is obtained of less than 10 mA and 200 μs pulse width stimulation No response with intensities above 15 mA was found to be
98 % accurate for properly implanted screws [20] The reported rate for false neg-atives and sensitivity is 8 % and 93 %, respectively [44, 83] This technique also allows for continuous EMG recording, so that changes can be observed on decompressing the roots, cage positioning and rod placement No neuromuscu-lar relaxant drug (NMB) effects have to be observed (at least three out of four twitches in the train-of-four) over the period of surgical EMG monitoring
Wake-up Test
A WUT consists of stopping the anesthetics after surgical spine manipulation to assess the motor function of the spinal cord and nerve roots Usually the spinal cord, brachial plexus roots, and L5 and S1 can be evaluated by asking the patient
to move their hands and feet The WUT is an outstanding procedure for ascer-taining corticospinal and motoneuron integrity In experienced hands a WUT is quick, reliable, safe and reproducible It requires 5 – 15 min notice from the sur-geon to conduct it Many spine sursur-geons feel comfortable omitting a WUT when reliable data with SSEPs and MEPs are obtained and maintained The WUT is currently performed when there is no SSEP/MEP data available or in
circum-stances where these methods are not reliable The limitations of the WUT are:
Spinal cord monitoring
has replaced WUTs
in many centers
) intermittent rather than continuous monitoring
) not applicable in mentally handicapped patients
) not feasible in small children
) preexisting severe spinal cord damage (incomplete lesion) Venous embolism, corneal damage, loss of vascular access, violent wake-up, acci-dental extubation or hardware dislodgement is unlikely when the test is con-ducted in skilled hands The WUT technique requires training and practice to master and be used with confidence A normal WUT with posterior column damage or “false negative” (with documented intraoperative SSEP deficit) has been reported by Ben-David [6] This is not a true false negative because SSEPs and the classic WUT are aimed at different anatomic structures: dorsal column and anterior spinal cord blood supply We have refined a WUT that allows us to test both sensory/proprioceptive and motor components in a reliable and quiet fashion
Trang 7End of Anesthesia
Planning for postoperative pain control, elective postoperative ventilatory
sup-port and postoperative destination should be conducted before starting the
sur-gery However, emergency cases and unexpected intraoperative events might
require fast intraoperative decision-making Ideally patients should be quickly
regaining the ability to follow commands to assess their neurological status, be
comfortable with coughing to clear secretions and starting with physiotherapy
The provision for pain management is discussed in the next section Elective and
last minute decisions to keep the patient in the intensive care unit are shown in
Table 6 Patients with major comorbidities before surgery and/or unexpected
adverse intraoperative events account for most indications for the postoperative
ICU Which patients should have postoperative ventilation? Most spine surgery
patients are extubated on the table at the end of the surgery Consideration for
postoperative mechanical ventilation should be given to patients undergoing
neuromuscular scoliosis correction, with preoperative respiratory or cardiac
The need for postoperative mechanical ventilation must be considered prior
to surgery
dysfunction, having intraoperative hemodynamic and respiratory instability,
with unexpected decreases in body temperature, with difficult airway access, or
with slow recovery from anesthesia [60] Although it is not our regular practice,
some groups suggest elective ventilation for a few hours after C-spine surgery to
make certain no airway compromise by hematoma is present after surgery and
before extubation
Table 6 Perioperative considerations regarding overnight ICU requirement
) preoperative severe respiratory
impairment
) cervical spine surgery: laryngeal nerve damage or hematoma
) respiratory failure ) mental disability ) hemodynamic instability
) hemodynamic instability ) congestive heart failure ) continued correction of hypovolemia
) special monitoring requirements ) chronic obstructive pulmonary disease ) surgical complications
) chronic renal failure ) coagulopathy
) muscular dystrophy ) anesthetic complications
) patient coming from ICU ) hypothermia
Postoperative Pain Management
Postoperative pain and gastrointestinal dysfunction (nausea, vomiting, ileus,
con-stipation and anorexia) secondary to analgesics and other drugs are among the
main factors delaying the recovery process in spinal surgery The goals of
postop-erative pain control therapies are to enhance recovery and decrease
complica-tions rather than just to decrease pain measured scores Challenges relate to
pre-operative pain and opioid tolerance, cognitive impairment, extremes of life and
difficulties assessing the symptoms and the results of the treatments applied A
multimodal approach is recommended, involving acetaminophen, low-dose
NSAIDs, systemic opioids, wound infiltration with local anesthetics and
coadju-vants (i.e., low-dose ketamine, stool softeners and gabapentin) The requirements
of preoperative opioids do not disappear right after the surgery It might take
weeks Therefore, it is recommended to restart them as baseline analgesia as soon
as the patient can receive them orally or to replace them temporarily intravenously
Multimodal Analgesia.Acetaminophen is extremely well tolerated and can be
used before beginning the surgery per rectum, per os or intravenously (as
Trang 8propa-racetamol) in doses of 15 mg/kg every 4 – 6 h Metamizol (Dypirone) is an excel-lent alternative to acetaminophen at the same dose regimen provided the patient The postoperative
use of NSAIDs remains
a matter of debate
is not allergic to it and has no bone marrow disease The postoperative use of NSAIDs has been the subject of heated controversy in the literature because of data coming from animal studies and retrospective human chart reviews There
is not a single prospective randomized trial on spine surgery in humans demon-strating a higher incidence of malunion or a slower consolidation secondary to short use (3 – 5 days) of NSAIDs On the contrary, the literature shows similar surgical outcomes with better pain control in patients who received ketorolac at less than 110 mg/day after spine procedures [22, 51, 61] These analyses have actually emphasized that preoperative smoking increases the risk of malunion by
8 – 15 times NSAIDs only become an issue when they are used in high doses in smokers If the patient is going to have low molecular weight heparin postsurgery
(uncommon in spine procedures), it seems safer to use a COX- 2 specific such as
celecoxib (rule out cardiovascular contraindications) Wound infiltration at the beginning and the end of the operation greatly reduces the amount of anesthetics and opioids required in the first few hours after surgery, allowing patients to be scheduled to go home the same day (i.e., after disc surgery) and a smoother
tran-sition and discharge Patient controlled analgesia (PCA), nurse or parent
assisted PCA or regular subcutaneous opioids are the most commonly used anal-gesia technique after spine procedures Side effects are often prominent includ-ing gastrointestinal, excessive sedation, respiratory depression and poor inci-dental pain relief
The advantages of using epidural analgesia after scoliosis surgery (Fig 5) have been reported by Blumenthal [9] and Tobias [78] Both methods (PCA and epidu-ral) provided efficient postoperative analgesia However, the double epidural catheter technique provides better postoperative analgesia, earlier recovery of bowel function, fewer side effects, and higher patient satisfaction
Figure 5.
Cervicothoracic epidural catheter
Epidural catheter at the level of C7/T1 allows for excellent pain control in cases with posterior fusion and/or a transthoracic approach.
Trang 9Communication.Anesthesiologists with special
ex-pertise in spine surgery play an important role in
the perioperative team in charge of patients The
anesthesiologist will lay out a plan to manage
anes-thesia in each case, but this plan must be closely
in-tegrated into the surgical plan Therefore, the
anes-thesiologist must be involved before surgery to
permit a team plan for the case, no matter how
sim-ple it may seem
Goals in spinal surgery.Critical aspects of the
intra-operative anesthesia care are airway management,
positioning on the operative table, techniques to
minimize surgical bleeding, pain control and organ
perfusion Techniques to control bleeding must be
balanced against ocular complications and cord
function and perfusion Techniques to secure the
airway must be balanced against spinal cord injury
Techniques to achieve proper pain control
postsur-gery must be balanced against effective bone
fu-sion and clean healing
Induction of anesthesia.In this period, the critical
issues are airway control and hemodynamic
stabili-ty Patients with an unstable cervical spine require
careful fiberoptic tube placement, avoiding drops
in blood pressure that might further jeopardize the
cord condition Patients coming for transthoracic
surgical approaches might require lung deflation
by using a bronchial blocker or other device to
facil-itate surgical exposure There is no evidence to
sup-port the use of armored endotracheal tubes
Antibi-otic prophylaxis before starting the operation is
mandatory in most spine surgery cases to preclude
colonization of implants
Maintenance of anesthesia. In the maintenance period of major spine cases, controlled hypoten-sion to MAP not below 60 – 65 mm Hg along with tranexamic acid is an efficacious means to control bleeding and allow for a drier surgical field Intrao-perative neuromonitoring requires stable tempera-ture, anesthesia depth with low doses of gases or TIVA and good cord perfusion Guidelines are pro-vided for transfusions in the spine surgery scenario
as well as a clear and simple description of the wake-up test for places without an SSEP machine
In simple cases of day surgery procedures, the goals are rapid recovery of anesthesia without nausea, vomiting and pain Local anesthesia infiltration before the surgery and at the end facilitates an an-esthetic approach with minimal opioids
End of anesthesia.At the conclusion of the anes-thesia and surgery, the issues are pain control and again airway management Multimodal analgesia along with epidural catheters offers excellent re-sults with low morbidity and high levels of patient (and surgeon) satisfaction NSAIDs in low doses (ke-torolac < 90 mg/day or celecoxib < 200 mg/day) and for less than 72 h postoperatively are a safe and effective part of the cocktail as long as the patient is
a nonsmoker The decision to keep the patient intu-bated in the first few hours after C-spine or major spine operations should rely on the clinical assess-ment by the team regarding the physiologic and anatomic conditions of the individual patient
Key Articles
Lauer KK ( 2004) Visual loss after spine surgery J Neurosurg Anesthesiol 16:77–79
Brief review of the topic with excellent and concise information to understand why this
complication occurs in spine surgery.
Sessler D ( 2001) Complications and treatment of mild hypothermia Anesthesiology
95:531–43
The author analyzes the clinical implications of perioperative hypothermia An
impor-tant paper that presents very practical information about the deleterious effects of mild
hypothermia on infectious, metabolic and hemostatic aspects usually unknown to many
clinicians.
Tobias JD ( 2004) Strategies for minimizing blood loss in orthopedic surgery Semin
Hematol 41(1):145–56
Comprehensive review of the current techniques to preserve blood in spine surgery.
Trang 10Key Articles www.asahq.org/publicationsAndServices/transfusion.pdf
This web site of the American Society of Anesthesiology presents very well documented guidelines about blood product therapy in the perioperative period It is frequently updated with new information and is easy to read.
Duffy G, Neal KR ( 1996) Differences in postoperative infection rates between patients receiving autologous and allogeneic blood transfusions: a meta-analysis of published randomized and nonrandomized studies Transfus Med 6(4):325–28
The authors reviewed seven trials comparing autologous vs allogeneic transfusions; only two were prospective randomized trials with around 80 patients on each arm This meta-analysis suggested at least a twofold increase in postoperative infections in patients hav-ing allogeneic transfusions of 1 – 4 units.
Sethna NF, Zurakowski D, Brustowicz RM, Bacsik J, et al ( 2005) Tranexamic acid reduces intraoperative blood loss in pediatric patients undergoing scoliosis surgery Anesthesiology 102:727–32
A recent and well done protocol that demonstrates a greater than 40 % reduction in bleed-ing durbleed-ing spine surgery by usbleed-ing tranexamic acid There was a clear trend to lower trans-fusion rates in the tranexamic group; however, it did not reach statistical significance.
Tobias JD ( 2004) A review of intrathecal and epidural analgesia after spinal surgery in children Anesthes Analg 98(4):956–65
A close look into the pediatric field of post spine surgery analgesia by an expert in pediat-ric orthopedic anesthesia An interesting view of the use of regional anesthesia and spinal opioids.
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