S.H. Sadrolsadat et al. / Surgical Neurology 71 (2009) 60–65 61
to avoid nerve injury, brachial plexus palsy, or pressure The SA patients were placed in the seated position on
necrosis to either the face or the chest wall [4,14]. Spinal arrival in the operating room. After the injection of local
techniques may also reduce the incidence of pulmonary anesthetics (1 mL of lidocaine 1%), SA was delivered using
complications compared with GA; however, episodes of a lumbar puncture at the L3-4 intervertebral disk space via
urinary retention and infection were reported following this Quincke 25-gauge spinal needle and injection of 4 mL of
method [13,19]. bupivacaine 0.5% in the subarachnoid space.
There have been very few RCTs regarding this subject in Once the block was obtained, the patients were rolled
the literature [3,7,11,12]. The purpose of this study was to into the supine position and allowed to rest until a stable
conduct an acceptable RCT to compare the intraoperative maximal spread of the block to T6 through T10 was
parameters and postoperative outcome after SA and GA in achieved. After about 10 minutes, the patient was turned
patients undergoing elective lumbar disk surgery. to a prone position on the operating bed and placed on
the standard laterally located chest roles in the semiflexed
position. Oxygen was provided via face mask. During the
2. Material and methods operation, the patient was sedated with propofol infusion
at 25 to 50 μg/(kg min) IV. At completion of the
2.1. Ethics and inclusion criteria operation, propofol was discontinued; and the patient was
After approval of the study protocol by the Institutional rolled to supine position. The patients were then
Ethical Board Committee, all the patients awaiting lami- transferred to the PACU. There were no dropouts in
nectomy for herniated lumbar disk in 1 to 2 levels during the this series of patients.
years 2005 and 2007 were enrolled in the study. 2.3. Data gathering
Those with an ASA class higher than class III; patients
Age, sex, height, and weight were the demographic
with multilevel spinal stenosis, coagulopathy, localized
characteristics entered for every patient. Electrocardio-
infection (interpreted as a contraindication or a high risk
graphic monitoring, noninvasive blood pressure, pulse
for SA), or severe cardiac or liver disease; and cases with any
oximeter, and capnography were recorded during the
relative or absolute contraindication for SA  were
operation in both groups.
excluded from the study.
The patient's HR (per minute) and MAP were recorded at
An informed consent was obtained from all the patients
after enough description about the different methods being
used for the patient during surgery. The patients were
1. The time at which the patient had entered the operation
allocated into 2 groups based on computer-generated
randomization. They were selected to undergo either GA
2. The time anesthesia was initiated,
or SA. A single surgeon and a group of anesthesiologists
3. At the initiation of the operation (when incision was
were responsible for performing all the operations. A
trained technician unaware of the objectives of the study
4. At the termination of the operation (placement of surgical
and the method by which the patient was operated was
responsible for gathering the required information.
5. Once anesthesia was terminated (when the patient was
2.2. Techniques transferred to the recovery room), and
6. When the patient was discharged from the recovery room.
Patients undergoing GA were given 2 mg of IV
midazolam. Induction was carried out using propofol IV Mean arterial pressure and HR were also assessed every
(2 mg/kg) and fentanyl IV (2 μg/kg). Endotracheal 10 minutes for at least half an hour in the recovery room in
intubation was facilitated with atracurium IV (0.5 mg/kg). both study groups (sample of the graphs taken for each
Once the patients were intubated, they were placed in a prone patient in Figs. 1 and 2).
position on a standard operating frame. Maintenance The amount of blood loss was assessed by measuring
anesthesia consisted of oxygen 100% with propofol (100- the bloody gauzes' weight plus the volume calculated from
200 μg/[kg min]) and alfentanil (2 mL/400 mg propofol). the difference of suctioned fluid and the volume of
Anesthetics were modified to maintain hemodynamic irrigation solutions administered (for the purpose of
variables within 10% of the baseline values. Ten milligrams washing the operation site). The infused liquid during
of atracurium was administered every 20 minutes as muscle anesthesia, accounting for those administered before
relaxant. At the termination of GA, the anesthetic agents induction, was documented.
were discontinued; and the patient breathed 100% oxygen. The severity of pain and nausea was evaluated using
The patient was then rolled to a supine position on the 100-mm VAS; meperidine (25 mg IV) and metoclopramide
postoperative bed. At that time, atropine and neostigmine were prescribed in cases with pain intensity more than
were used to reverse the relaxation. When appropriate, they 50 mm and nausea more than 50 mm, respectively. Both
were extubated and then transported to the PACU. drugs were readministered in intervals of 30 minutes, if
62 S.H. Sadrolsadat et al. / Surgical Neurology 71 (2009) 60–65
The demographic and baseline data of the 2 groups enrolled in the study
Age 45.2 ± 5.6 45.7 ± 5.2
Weight 75.2 ± 8.2 77.8 ± 7.5
Baseline MAP 92.6 ± 4.9 93.3 ± 6.2
Baseline HR 78.2 ± 6.4 78.6 ± 7.0
assessed to be hemodynamically stable and comfortable at
the time of discharge. The total stay of the patients in PACU
was also recorded.
Hypotension or bradycardia was defined as the reduction
of MAP or HR to less than 80% of the baseline amounts.
Fig. 1. Sample of a graph showing the changes in MAP of a patient during
Ephedrine IV 10 mg or more was administered in such cases.
the study period. Numbers in the x-axis denote the time intervals at which
MAP was assessed: 1, the time at which the patient had entered the operation On the other hand, hypertension or tachycardia was
room; 2, the time anesthesia was initiated; 3, after the intubation; 4, at the considered when MAP or HR had raised to more than
initiation of the operation (when incision was performed); 5, at the 120% of the baseline. These cases were treated using 20 to
termination of the operation (placement of surgical dressing); 6, once 30 mg of propofol IV and/or TNG with an initial dose of
anesthesia was terminated (when the patient was transferred to the recovery
room); and 7, when the patient was discharged from the recovery room.
During the pilot study, the difference between the
hypotension rate in the 2 groups was calculated (15% vs
required. The reinjection of the drugs every 4 hours was 40%); according to this findings and with α = .05 and a
possible when the patient was transferred to the ward. power of 80%, a sample size of 100 (50 patients in each
The number of blood bags injected during the operation, group) was required.
the preoperative and postoperative values of hemoglobin, The data were analyzed using SPSS (Chicago, IL) version
and the satisfaction rate of the surgeon were recorded. 11.5 software. The χ2 test and the Student t test were used
Surgeon's satisfaction was evaluated using a 100-mm for comparing the variables between the 2 groups. P values
VAS based on the satisfaction from the amount of blood in lower than .05 were considered as significant.
the surgical field, patients' muscular relaxation, being
motionless, and the possibility of assessing neurologic
status immediately after the operation. The plausibility and 3. Results
internal validity of the variants considered for VAS of the
One hundred patients were enrolled in this study. The
surgeon's satisfaction rate were examined in several
mean age of the patients was 45.5 ± 5.4 years, and 50% were
introductory sessions with the attending surgeons and
male. There was no difference between the demographic data
gained acceptable rates.
and the baseline MAP and HR of the 2 groups (Table 1).
Patients were discharged from the recovery room based
The perioperational findings of both groups are outlined
on Miller's Anesthesia 2005 guidelines, TOF ratio equal to
in Table 2. Regarding the surgical and anesthesia durations,
0.85 in GA patients, and the regression of at least
no statistically significant difference was observed between
4 dermatomes block in SA patients. All the patients were
the 2 groups (P = .932 and .084, respectively). In comparison
with the SA patients, the GA group lost about 26.5 ± 2.7 mL
less blood during the operation, which was marginally
significant (P = .054). Anyhow, no episodes of excessive
hemorrhage or cases requiring blood transfusions occurred in
Intraoperative data for SA vs GA
GA (n = 50) SA (n = 50) P
Total anesthesia time (min) 126.4 ± 19.1 120.1 ± 16.9 .084
Operation time (min) 94.1 ± 17.9 94.4 ± 17.3 .932
Blood loss (mL) 438.0 ± 66.6 464.5 ± 69.3 .054
Hypotension 6 (12%) 24 (48%) b.001
Bradycardia 17 (34%) 17 (34%) 1.000
Tachycardia 13 (26%) 3 (6%) .006
Fig. 2. Sample of a graph showing the changes in HR of a patient during the
IV fluid (mL) 2890.0 ± 290.8 2930.0 ± 378.1 .555
study period. Numbers in the x-axis denote the time intervals at which HR
Surgeon's satisfaction 76.7 ± 7.5 64.0 ± 6.5 .038
was assessed (see Fig. 1 for interpretation of the numbers).
S.H. Sadrolsadat et al. / Surgical Neurology 71 (2009) 60–65 63
Table 3 4. Discussion
Postoperative data for SA vs GA
GA SA P OR (95% CI)
A good anesthetic technique should have both rapid onset
and reversal of effects. It should provide desirable
Hypertension 19 (38%) 3 (6%) b.001 9.6 (2.6-35.2)
PACU time 23.8 ± 7.8 21.7 ± 8.8 .212 –
intraoperative hemodynamic conditions and, if possible,
Nausea and vomiting 3 (6%) 10 (20%) .037 3.9 (1.1-15.1) contribute to a reduced need for blood transfusion. More-
in PACU over, it should permit the earliest possible discharge from the
Nausea and vomiting 9 (18%) 5 (10%) .249 – PACU and minimize the common postoperative problems
after 24 h such as pain, analgesics consumption, nausea, and vomiting
Analgesic requirement 31 (62%) 11 (22%) b.001 5.7 (2.4-13.9)
Analgesic requirement 37 (74%) 38 (76%) . 817 - The literature is largely supportive regarding SA used for
after 24 h lumbar laminectomy, although not in an evidence-based
OR indicates odds ratio; CI, confidence interval. manner; however, GA is the method of choice for spinal
procedures according to some authors . This concept
either may be related to the lack of familiarity with the use of
either group. Furthermore, just 12% of GA patients spinal techniques for anesthesia in such procedures or may
compared with 24% of SA ones experienced hypotension reflect the uncertainty concerning the potential risks and
during the operation (P b .001). complications incurred when spinal operations are carried
Bradycardia was similarly seen in both groups, whereas out in a conscious patient under SA .
tachycardia was more frequent in those undergoing GA Several studies have compared SA and GA in lumbar
(26% vs 6%, P = .006). It is noteworthy that, in 3 cases of the laminectomy surgery, and many of which have concluded
SA group, coughing impeded the surgeons from proceeding SA as the preferred method [7,3,11,12]. However, the pre-
for a while and that, in 1 case, hiccups made the condition sent study did not support this hypothesis. Table 4 outlines
tense. However, no major intraoperative complication was the findings of the similar studies.
reported in either of the series. On the whole, surgeon's In the present study, lower prevalence of nausea and
satisfaction measured by VAS was higher in GA patients vomiting in the following day of the surgery, shorter
(76.7 ± 7.5 mm) compared with SA patients (64.0 ± 6.5 mm), recovery time, and lower need for analgesics during the
which was statistically significant (P = .038). recovery period were reported in patients undergoing SA.
The postoperative findings are summarized in Table 3. The patients in the GA group were reported to experience
Duration of recovery period was rather similar in the intraoperative hypotension as well as nausea and vomiting
2 groups (GA, 23.8 ± 7.8 minutes vs SA, 21.7 ± 8.8 minutes). (in the recovery room) less frequently than the other group.
During the period, 19 of GA cases (38%) had hypertension The surgeons were also more satisfied with this method.
episodes, whereas just 3 cases of the other group experienced A number of confounding factors could explain this
it (P b .001). Postoperative nausea and vomiting were more discordance. (a) Tolerating the prone position for about an
frequent among patients recovering from SA compared with hour, during disk surgery, is not possible unless the patient
GA (20% vs 6%, P = .037). Conversely, in the day after the is sedated. One of the best sedative agents administered for
operation, nausea and vomiting occurred 8% more in GA this purpose is propofol. It has short-term effects; and
cases than SA ones, although it was not statistically therefore, the sedative effects disappear within a few minutes
significant (P = .249). after the interruption of the drug infusion. The antivomiting
Patients in the SA group required less analgesics effect of this drug even in low doses (10-15 mg) is well
immediately after the operation, and the difference was known ; moreover, it has been shown that it can reduce
statistically significant (62% vs 22%, P b .001). However, bleeding by decreasing the systemic vascular resistance by
the need became similar on the day after the operation 15% to 25% . Propofol infusion was administered as
(74% vs 76%). the sedative agent in the group undergoing SA in several
Comparing SA vs GA outcomes of the RCTs conducted on patients undergoing laminectomy in the systematic review performed in Medline, Cochrane,
Scopious, and advanced G-scholar using the key words GA, (and) SA, (and) comparison, (and) laminectomy, compared with the present study
Study n N&V Bleeding RT AC Complication
Jellish et al (1996)  122 GA N SA GA N SA SA N GA GA N SA SA = GA
Demeril et al (2003)  60 GA N SA GA N SA SA = GA GA N SA GA = SA
McLain et al (2004)  200 GA N SA GA N SA SA N GA GA N SA GA N SA
McLain et al (2005)  400 GA N SA GA N SA SA N GA GA N SA GA N SA
This series 100 SA N GA GA = SA SA = GA GA N SA GA = SA
N&V indicates nausea and vomiting in the recovery room; bleeding, the amount of intraoperative bleeding; RT, recovery time; AC, analgesic consumption in the
64 S.H. Sadrolsadat et al. / Surgical Neurology 71 (2009) 60–65
studies; however, the patients in the other group did not 7. It should also be kept in mind that the surgeons are not
receive such an agent. Therefore, administration of the able to evaluate the patients' neurologic status
propofol was one of the factors altering the results of those immediately after the operation in the SA because of
studies [7,11,12]. In the present study, propofol was used as the motor block state that happens during this type of
the sole hypnotic and sedative agent in both the GA and SA anesthesia. That is one of the major drawbacks of SA
groups. (b) Inaccurate calculation of the patients' fluid for disk surgery. It is noteworthy that very few studies
requirement was the second confounding factor cited in in this field have evaluated the surgeons' satisfaction
those studies. The fluid infused during the operation is rate not only because there may be no standard scaling
normally assumed by considering the patients' weight, technique for it but because close cooperation between
the duration of anesthesia, the minimum NPO duration, the the anesthesiologist and the attending surgeon is
amount of the fluid loss, the CVE, the third space, the necessary to develop a reliable VAS.
insensible water loss, and the bleeding compensation.
According to Jellish et al , the amount of infused fluid Along with these concerns, there are some other
was reported to be approximately 800 1100 mL less than important points that reduce the anesthesiologists' prefe-
the required amount. They also showed that the average rence for SA, such as:
amount of bleeding and the duration of anesthesia were also
reported to be more in the GA group. In other words, the 1. Although anesthesiologists are interested in SA as a
required fluid was not completely compensated in the more reliable method, experience shows the prolonged
abovementioned study; thus, the hemodynamic changes operation performed in the prone position under SA
cannot exclusively be attributed to the kind of anesthesia increases the anesthesiologist's stress and anxiety.
applied. (c) Regarding the operation time and the amount of 2. Heightening of the blocked level leading to apnea is
blood loss during operation, both of them look to be another possible worrying complication using this
“confounding factors” rather than independent variables method, compared with GA anesthesia.
because the surgeons usually turn the patients into the prone 3. Managing an apneic patient, providing an airway
position according to their own will and satisfaction, so no access, and placing an endotracheal tube in the prone
neurosurgeon is actually blind about the patient allocation position are difficult.
to either GA or SA group! That makes a major bias for the 4. In addition, the infusion of the anesthetic agent may be
surgeon. First, the surgeon may take his/her time for a accompanied with amnesia; any decrease in the
satisfactory and complete surgery without being worried sedation depth (which is common) is accompanied
about the length of operation being inconvenient for the with involuntary, sudden movements in the patient's
patient in the prone position. Second, the longer the upper body, resulting in possible nerve root injuries
operation, the more will be those minimal changes in [9,21]. Cough and hiccups are also recurrently
the amount of bleeding during operation. reported during this type of anesthesia [3,16].
According to the findings of the present study, each
method has its own preferred characteristics: According to the abovementioned results, it could be
concluded that GA causes less intraoperative bleeding
1. Considering the hemodynamic stability, the incidence accompanied by a higher hemodynamic stability; it also
of bradycardia was equal in both methods. provides a relatively higher satisfactory condition for the
2. The prevalence of hypotension and, consequently, surgeon and the patient. It should be noted that an increased
the administration of ephedrine were higher in SA; risk of bleeding, nausea, vomiting, and hemodynamic
conversely, hypertension was more frequently instability is reported after a typical GA sedation using
reported after the operation in the patients who had inhaled anesthetics, although the present study revealed that
undergone GA. the administration of propofol via TIVA in these operations
3. The incidence of tachycardia was higher in GA, reduces the incidence of such adverse effects.
occurring mainly during the intubation period. For-
tunately, none of the 100 patients under study reported
any complication due to the hemodynamic changes.
4. The average intraoperative bleeding and need for fluid The findings of the present study revealed that SA has no
were not significantly different in the 2 groups. acceptable advantage over GA in lumbar disk surgery.
5. In the recovery room, the number of patients with pain Moreover, it could support the hypothesis that GA
who needed analgesics was less in the SA group; this can reduce the related risks and complications in several
could be due to the anesthetic agent's effect. aspects and rule out the first hypothesis suggested in
6. On the other hand, nausea and vomiting were more the introduction.
prevalent among the patients recovering from SA However, further well-designed studies including more
because of the unopposed parasympathetic activity sample cases are still needed to evaluate the accuracy of the
occurring with this method . abovementioned findings.
S.H. Sadrolsadat et al. / Surgical Neurology 71 (2009) 60–65 65
Acknowledgment  Reves JG, Glass PSA, Lubrasky DA, McEvoy MD. Intravenous non-
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