SPINE Volume 39, Number 22, pp 1910-1916 ©2014, Lippincott Williams 8c Wilkins
Spine
S urgery Use o f an O p e ra tin g M ic ro s c o p e D u rin g Spine Surgery Is A ssociated W ith M in o r Increases in O p e ra tin g Room Times and N o Increased Risk o f In fe c tio n Bryce A. Basques, BS, N ich o la s S. G o lin va u x, BA, D a n iel D. Bohl, M P H , A le m Y a co b , M D , Jason O . Toy, M D , A rya G. V arthi, M D , and Jonathan N. Grauer, M D
M icroscope use was associated w ith m inor increases in preoperative
Study Design. Retrospective database review. O bjective. To evaluate w hether microscope use during spine procedures is associated w ith increased operating room times or increased risk o f infection.
Sum m ary o f Background D ata. O perating microscopes are co m m only used in spine procedures. It is debated w hether the use o f an operating m icroscope increases operating room tim e or confers increased risk o f infection.
M ethods. The Am erican College o f Surgeons National Surgical Q u a lity Im provem ent Program database, w hich includes data from more than 370 participating hospitals, was used to identify patients undergoing elective spinal procedures w ith and w ith o u t the use of an operating microscope for the years 2011 and 2012. Bivariate and m ultivariate linear regressions were used to test the association between m icroscope use and operating room times. Bivariate and m ultivariate logistic regressions were sim ilarly conducted to test the association between microscope use and infection occurrence
room tim e (+ 2 .9 m in, P = 0.013), operative tim e (+ 1 3 .2 m in, P < 0.001), and total room tim e (+ 1 8 .6 min, P < 0.001) on m ultivariate analysis. A total of 328 (1.4%) patients had an infection w ithin 30 days o f surgery. Multivariate analysis revealed no significant difference between the microscope and nonmicroscope groups for occurrence o f any infection, superficial surgical site infection, deep surgical site infection, organ space infection, or sepsis/septic shock, regardless o f surgery type.
Conclusion. W e did not fin d operating room times or infection risk to be significant deterrents for use o f an operating microscope during spine surgery.
Key words: operating microscope, surgical site infection, sterility, operative time, National Surgical Q u a lity Im provem ent Program, outcomes, spine, cervical, thoracic, lumbar.
Level o f Evidence: 3 Spine 2014;39 :1 9 10 -1 91 6
w ith in 30 days o f surgery.
Results. A total
o f 23,670
elective
spine
procedures
were
identified, o f w hich 2226 (9.4%) used an operating microscope. The average patient age was 55.1 ± 14.4 years. The average operative tim e (incision to closure) was 125.7 ± 82.0 minutes.
From th e D e p a rtm e n t o f O rth o p a e d ic s a n d R e h a b ilita tio n , Yale S ch o o l o f M e d ic in e , N e w H a ve n , CT. A c k n o w le d g m e n t d ate: A p ril 2 2 , 2 0 1 4 .
R e visio n
d ate: June 11, 2 0 1 4 .
A c c e p ta n c e d ate: July 15, 2 0 1 4 . T he m a n u s c rip t s u b m itte d d o e s n o t c o n ta in
in fo rm a tio n a b o u t m e d ic a l
d e v ic e (s )/d ru g (s). T he N a tio n a l C e n te r fo r A d v a n c in g T ra n s la tio n a l Sciences o f th e N a tio n a l In stitu te s o f H e a lth u n d e r A w a rd N u m b e r T L 1 T R 0 0 0 1 4 1 fu n d s w e re re c e iv e d in s u p p o rt o f th is w o rk . R e le va n t fin a n c ia l a c tiv itie s o u ts id e th e s u b m itte d w o rk : co n s u lta n c y , e x p e rt te s tim o n y , grants. A dd re ss c o rre s p o n d e n c e a n d re p rin t requests to Jonathan N . G rauer, M D , D e p a rtm e n t o f O rth o p a e d ic s a n d R e h a b ilita tio n , Yale S ch o o l o f M e d ic in e , 8 0 0 H o w a rd Ave, N e w H a ve n , C T 0 6 5 1 0 ; E -m ail: jo n a th a n .g ra u e r@ y a le .e d u D O I: 1 0 .1 0 9 7 /B R S .0 0 0 0 0 0 0 0 0 0 0 0 0 5 5 8
1910
w w w .s p in e jo u rn a l.c o m
he operating microscope is commonly considered for use in spine surgery. Advocates of this tool tout its abil ity to improve visualization for the surgeon and surgi cal team without increasing the size of the surgical incision. 1’2 However, others cite concerns that the use of the operating microscope may increase operating room times and increase risk of infection. 3-5 Increased operative time has been shown to be an inde pendent risk factor for postoperative complications in spine surgery. 6 Time spent preparing and using the microscope has the potential to lengthen operating room times compared with nonmicroscope cases. Although some studies have found oper ating microscopes to be associated with increased operative time, these results may be outdated and are limited by a small sample size. 7' 10 Additional information is needed about the potential effects of microscope use on operating room times. Surgical site infections (SSIs) after spine surgery are associ ated with poor outcomes and high costs. 11 Several potentially modifiable risk factors for SSI include preoperative bacterial
T
O c to b e r 2 0 1 4
Spine
S urgery
screening, skin preparation, prophylactic antibiotic admin istration, the degree of surgical trauma, the operating room environment, and operative equipment.3' 5’12-16 In particular, previous studies have found bacterial contamination of the operating microscope and other operating room equipment during spine surgery.3-5’13’17 It is not clear if this reported bac terial contamination of the microscope translates into an increased risk of infection for the patient. This study aims to use a national database to compare the operative times and rates of infections between spine proce dures that have used an operating microscope and those that have not. M A T E R IA L S A N D M E T H O D S D ata Source
For this study, we used the American College of Surgeons National Surgical Quality Improvement Program (ACSNSQIP) database, which captures data from more than 370 participating US hospitals.18 The ACS-NSQIP prospec tively collects more than 150 patient variables from opera tive reports, medical records, and patient interviews to assess 30-day adjusted surgical outcomes using specially trained clinical reviewers. The ACS-NSQIP conducts routine auditing to maintain high data quality, and inter-rater disagreement is below 2% for each collected variable.18’19 Clinical data are collected up to the 30th postoperative day, including after the patient is discharged from the hospital. D a ta C ollection
The ACS-NSQIP database from 2011 and 2012 was queried to identify patients who underwent elective spine procedures. Spine procedures were selected on the basis of the follow ing primary Current Procedural Terminology (CPT) codes: anterior cervical discectomy and fusion (22551, 22554, and 63075), anterior cervical corpectomy (63081), posterior cer vical fusion (22600), cervical laminotomy (63040), posterior thoracic fusion (22610), lumbar laminotomy (63030), lum bar laminectomy (63047), anterior lumbar fusion (22558), and posterior lumbar fusion (22612 or 22630). Cases with microscope use were identified by the presence of the CPT code 69990 in addition to one of the primary CPT codes mentioned in the earlier text. Although there may be other procedures that employ the operating microscope, these were the only elective spine procedures available in the ACS-NSQIP for which microscope use was noted. Procedures that used the operating microscope for all or part of the operation were included in the microscope group. The number of levels for each procedure was also available in the database. The number of levels for each procedure was determined on the basis of the presence of procedure-specific supplementary CPT codes for each additional level. Both 1-level and multilevel procedures were included in this study. Patients undergoing spinal procedures at multiple sites, patients undergo ing urgent or emergent surgery, or those with previous evidence of infection were excluded from the analysis. Patients with miss ing perioperative data were also excluded from the analysis. Spine
Operating Microscopes During Spine Surgery • Basques et al
Among the variables available in the ACS-NSQIP are patient characteristics including sex, age, height, and weight. Body mass index (BMI) was calculated from height and weight. The ACS-NSQIP also includes information on medi cal comorbidities and American Society of Anesthesiologists (ASA) class. A modified Charlson Comorbidity Index (CCI)20 was calculated for each patient on the basis of the available comorbidity data in the database. Modified CCI calculations were performed with the statistical software, using an algo rithm that has been previously used and validated with the ACS-NSQIP.21 Such modified CCIs have been shown to be similar in efficacy to the original CCI.22’23 The comorbidities used to determine the modified CCI were directly available in the data set and included (followed by corresponding point values): myocardial infarction (1), congestive heart failure (1), peripheral vascular disease or rest pain (1), transient ischemic attack or cerebrovascular accident (1), chronic obstructive pulmonary disease (1), diabetes mellitus (1), hemiplegia (2), end stage renal disease (2), ascites or esophageal varices (3), and cancer (6). One point was added for each decade greater than 40 years of age. O p eratin g Room Times
The ACS-NSQIP also records preoperative room time, opera tive time, postoperative room time, and total room time for surgical cases. Preoperative room time was defined as the minutes between the patient entering the operating room and the opening incision. Operative time was defined as the min utes from opening incision to wound closure. Postoperative room time was defined as minutes from wound closure to the patient leaving the operating room. Preoperative room time, operative time, postoperative room time, and total room time were treated as continuous variables for analysis. Patients were excluded from the operat ing room time analyses if their data for any operating room time were missing. Infection
The ACS-NSQIP records the occurrence of various postop erative events, including infection, for up to 30 days after the surgical procedure. The ACS-NSQIP defines SSIs according to the Centers for Disease Control and Prevention (CDC)/ National Nosocomial Infections Surveillance guidelines.24 According to these guidelines, an SSI is defined as an infection that involves skin or subcutaneous tissue (superficial), fascia or muscle layers (deep), or any other anatomic components manipulated during surgery (organ space). The occurrence of sepsis or septic shock was also recorded. Any infection was defined as the occurrence of a superficial SSI, deep SSI, organ space infection, or sepsis/septic shock. Analysis
Statistical analyses were conducted using Stata version 11.2 (StataCorp, LP, College Station, TX). Statistical significance was set at P < 0.05. One member of the study team con ducted data extraction and statistical analyses. The Pearson x2 test was used to compare patient and operative characteristics www.spinejournal.com
1911
Spine
S urgery
Operating Microscopes During Spine Surgery • Basques et al
(9.4%) underwent surgery with the use of an operating microscope. A summary of patient demographics and comor bidities can be found in Table 1. The average age was 55.1 ± 14.4 years. Males comprised 51.6% of the cohort. Among all patients, 36.8% were ASA 3 to 4, and 43.5% had a modified CCI of 3 or greater. Comparison of patient characteristics using the Pearson \ 2 analysis found statistically significant differences between the microscope group and nonmicroscope group for age, BMI, modified CCI, and the number of levels. P values reported in Table 1 are for comparisons between all categories of each given demographic group. Patients undergoing spine surgery with the use a microscope were younger, had a lower BMI and modified CCI, and had fewer operative levels compared with the non microscope group. Although these differences were statistically significant, due to the relatively small magnitude of most differ ences, it is unclear if they were clinically significant. Nonethe less, these differences in patient and operative characteristics were controlled for in subsequent multivariate analyses.
between patients who underwent spine surgery with and without the use of an operating microscope. Operating room times were compared between microscope and nonmicroscope groups using bivariate and multivariate linear regression (as operating room times were treated as continuous variables), using nonmicroscope cases as the ref erence. Multivariate analysis adjusted for demographic and comorbidity variables (age, sex, BMI, ASA class, and modi fied CCI) and operative variables (number of levels and pro cedure type). Bivariate and multivariate logistic regressions were used to compare the rates of infections that occurred with or without the use of an operating microscope because infections were treated as binary variables.
RESULTS P a tie n t a n d O p e r a t iv e C h a ra c te ris tic s
A total of 23,670 elective spine procedures were identified in 2011 and 2012 in the ACS-NSQIP. A total of 2226 patients
Patient Characteristics
O verall, N o. (% )
All Patients
W ith o u t Microscope
W ith Microscope
2 3 ,6 7 0 (100)
2 1 ,4 4 4 (90.6)
2 2 2 6 (9.4)
0.002
A g e (yr) 1 5 -3 9
1 4 .8
1 4 .5
1 7 .2
4 0 -4 9
2 0 .8
2 0 .6
2 1 .9
5 0 -5 9
2 5 .7
2 5 .9
2 3 .9
6 0 -6 9
2 1 .2
2 1 .4
1 9 .8
>70
1 7 .5
1 7 .5
1 7 .2
M a le sex
5 1 .6
5 1 .6
5 1 .4
0 .8 2 8
0.033
B o d y m ass in d e x 1 8 -2 5
21 .1
1 0 .9
2 2 .7
2 5 -3 0
3 4 .7
3 4 .6
3 5 .9
3 0 -3 5
2 5 .3
2 5 .3
24 .1
>35
1 9 .0
1 9 .2
1 7 .4
ASA 3 -4
3 6 .8
35.1
3 7 .0
0 .0 7 8
0.001
M o d ifie d C C I 0 -1
3 3 .4
33.1
3 7 .0
2
2 3 .0
2 3 .2
2 1 .5
>3
4 3 .5
4 3 .7
4 1 .5
Spine
S urgery Use o f an O p e ra tin g M ic ro s c o p e D u rin g Spine Surgery Is A ssociated W ith M in o r Increases in O p e ra tin g Room Times and N o Increased Risk o f In fe c tio n Bryce A. Basques, BS, N ich o la s S. G o lin va u x, BA, D a n iel D. Bohl, M P H , A le m Y a co b , M D , Jason O . Toy, M D , A rya G. V arthi, M D , and Jonathan N. Grauer, M D
M icroscope use was associated w ith m inor increases in preoperative
Study Design. Retrospective database review. O bjective. To evaluate w hether microscope use during spine procedures is associated w ith increased operating room times or increased risk o f infection.
Sum m ary o f Background D ata. O perating microscopes are co m m only used in spine procedures. It is debated w hether the use o f an operating m icroscope increases operating room tim e or confers increased risk o f infection.
M ethods. The Am erican College o f Surgeons National Surgical Q u a lity Im provem ent Program database, w hich includes data from more than 370 participating hospitals, was used to identify patients undergoing elective spinal procedures w ith and w ith o u t the use of an operating microscope for the years 2011 and 2012. Bivariate and m ultivariate linear regressions were used to test the association between m icroscope use and operating room times. Bivariate and m ultivariate logistic regressions were sim ilarly conducted to test the association between microscope use and infection occurrence
room tim e (+ 2 .9 m in, P = 0.013), operative tim e (+ 1 3 .2 m in, P < 0.001), and total room tim e (+ 1 8 .6 min, P < 0.001) on m ultivariate analysis. A total of 328 (1.4%) patients had an infection w ithin 30 days o f surgery. Multivariate analysis revealed no significant difference between the microscope and nonmicroscope groups for occurrence o f any infection, superficial surgical site infection, deep surgical site infection, organ space infection, or sepsis/septic shock, regardless o f surgery type.
Conclusion. W e did not fin d operating room times or infection risk to be significant deterrents for use o f an operating microscope during spine surgery.
Key words: operating microscope, surgical site infection, sterility, operative time, National Surgical Q u a lity Im provem ent Program, outcomes, spine, cervical, thoracic, lumbar.
Level o f Evidence: 3 Spine 2014;39 :1 9 10 -1 91 6
w ith in 30 days o f surgery.
Results. A total
o f 23,670
elective
spine
procedures
were
identified, o f w hich 2226 (9.4%) used an operating microscope. The average patient age was 55.1 ± 14.4 years. The average operative tim e (incision to closure) was 125.7 ± 82.0 minutes.
From th e D e p a rtm e n t o f O rth o p a e d ic s a n d R e h a b ilita tio n , Yale S ch o o l o f M e d ic in e , N e w H a ve n , CT. A c k n o w le d g m e n t d ate: A p ril 2 2 , 2 0 1 4 .
R e visio n
d ate: June 11, 2 0 1 4 .
A c c e p ta n c e d ate: July 15, 2 0 1 4 . T he m a n u s c rip t s u b m itte d d o e s n o t c o n ta in
in fo rm a tio n a b o u t m e d ic a l
d e v ic e (s )/d ru g (s). T he N a tio n a l C e n te r fo r A d v a n c in g T ra n s la tio n a l Sciences o f th e N a tio n a l In stitu te s o f H e a lth u n d e r A w a rd N u m b e r T L 1 T R 0 0 0 1 4 1 fu n d s w e re re c e iv e d in s u p p o rt o f th is w o rk . R e le va n t fin a n c ia l a c tiv itie s o u ts id e th e s u b m itte d w o rk : co n s u lta n c y , e x p e rt te s tim o n y , grants. A dd re ss c o rre s p o n d e n c e a n d re p rin t requests to Jonathan N . G rauer, M D , D e p a rtm e n t o f O rth o p a e d ic s a n d R e h a b ilita tio n , Yale S ch o o l o f M e d ic in e , 8 0 0 H o w a rd Ave, N e w H a ve n , C T 0 6 5 1 0 ; E -m ail: jo n a th a n .g ra u e r@ y a le .e d u D O I: 1 0 .1 0 9 7 /B R S .0 0 0 0 0 0 0 0 0 0 0 0 0 5 5 8
1910
w w w .s p in e jo u rn a l.c o m
he operating microscope is commonly considered for use in spine surgery. Advocates of this tool tout its abil ity to improve visualization for the surgeon and surgi cal team without increasing the size of the surgical incision. 1’2 However, others cite concerns that the use of the operating microscope may increase operating room times and increase risk of infection. 3-5 Increased operative time has been shown to be an inde pendent risk factor for postoperative complications in spine surgery. 6 Time spent preparing and using the microscope has the potential to lengthen operating room times compared with nonmicroscope cases. Although some studies have found oper ating microscopes to be associated with increased operative time, these results may be outdated and are limited by a small sample size. 7' 10 Additional information is needed about the potential effects of microscope use on operating room times. Surgical site infections (SSIs) after spine surgery are associ ated with poor outcomes and high costs. 11 Several potentially modifiable risk factors for SSI include preoperative bacterial
T
O c to b e r 2 0 1 4
Spine
S urgery
screening, skin preparation, prophylactic antibiotic admin istration, the degree of surgical trauma, the operating room environment, and operative equipment.3' 5’12-16 In particular, previous studies have found bacterial contamination of the operating microscope and other operating room equipment during spine surgery.3-5’13’17 It is not clear if this reported bac terial contamination of the microscope translates into an increased risk of infection for the patient. This study aims to use a national database to compare the operative times and rates of infections between spine proce dures that have used an operating microscope and those that have not. M A T E R IA L S A N D M E T H O D S D ata Source
For this study, we used the American College of Surgeons National Surgical Quality Improvement Program (ACSNSQIP) database, which captures data from more than 370 participating US hospitals.18 The ACS-NSQIP prospec tively collects more than 150 patient variables from opera tive reports, medical records, and patient interviews to assess 30-day adjusted surgical outcomes using specially trained clinical reviewers. The ACS-NSQIP conducts routine auditing to maintain high data quality, and inter-rater disagreement is below 2% for each collected variable.18’19 Clinical data are collected up to the 30th postoperative day, including after the patient is discharged from the hospital. D a ta C ollection
The ACS-NSQIP database from 2011 and 2012 was queried to identify patients who underwent elective spine procedures. Spine procedures were selected on the basis of the follow ing primary Current Procedural Terminology (CPT) codes: anterior cervical discectomy and fusion (22551, 22554, and 63075), anterior cervical corpectomy (63081), posterior cer vical fusion (22600), cervical laminotomy (63040), posterior thoracic fusion (22610), lumbar laminotomy (63030), lum bar laminectomy (63047), anterior lumbar fusion (22558), and posterior lumbar fusion (22612 or 22630). Cases with microscope use were identified by the presence of the CPT code 69990 in addition to one of the primary CPT codes mentioned in the earlier text. Although there may be other procedures that employ the operating microscope, these were the only elective spine procedures available in the ACS-NSQIP for which microscope use was noted. Procedures that used the operating microscope for all or part of the operation were included in the microscope group. The number of levels for each procedure was also available in the database. The number of levels for each procedure was determined on the basis of the presence of procedure-specific supplementary CPT codes for each additional level. Both 1-level and multilevel procedures were included in this study. Patients undergoing spinal procedures at multiple sites, patients undergo ing urgent or emergent surgery, or those with previous evidence of infection were excluded from the analysis. Patients with miss ing perioperative data were also excluded from the analysis. Spine
Operating Microscopes During Spine Surgery • Basques et al
Among the variables available in the ACS-NSQIP are patient characteristics including sex, age, height, and weight. Body mass index (BMI) was calculated from height and weight. The ACS-NSQIP also includes information on medi cal comorbidities and American Society of Anesthesiologists (ASA) class. A modified Charlson Comorbidity Index (CCI)20 was calculated for each patient on the basis of the available comorbidity data in the database. Modified CCI calculations were performed with the statistical software, using an algo rithm that has been previously used and validated with the ACS-NSQIP.21 Such modified CCIs have been shown to be similar in efficacy to the original CCI.22’23 The comorbidities used to determine the modified CCI were directly available in the data set and included (followed by corresponding point values): myocardial infarction (1), congestive heart failure (1), peripheral vascular disease or rest pain (1), transient ischemic attack or cerebrovascular accident (1), chronic obstructive pulmonary disease (1), diabetes mellitus (1), hemiplegia (2), end stage renal disease (2), ascites or esophageal varices (3), and cancer (6). One point was added for each decade greater than 40 years of age. O p eratin g Room Times
The ACS-NSQIP also records preoperative room time, opera tive time, postoperative room time, and total room time for surgical cases. Preoperative room time was defined as the minutes between the patient entering the operating room and the opening incision. Operative time was defined as the min utes from opening incision to wound closure. Postoperative room time was defined as minutes from wound closure to the patient leaving the operating room. Preoperative room time, operative time, postoperative room time, and total room time were treated as continuous variables for analysis. Patients were excluded from the operat ing room time analyses if their data for any operating room time were missing. Infection
The ACS-NSQIP records the occurrence of various postop erative events, including infection, for up to 30 days after the surgical procedure. The ACS-NSQIP defines SSIs according to the Centers for Disease Control and Prevention (CDC)/ National Nosocomial Infections Surveillance guidelines.24 According to these guidelines, an SSI is defined as an infection that involves skin or subcutaneous tissue (superficial), fascia or muscle layers (deep), or any other anatomic components manipulated during surgery (organ space). The occurrence of sepsis or septic shock was also recorded. Any infection was defined as the occurrence of a superficial SSI, deep SSI, organ space infection, or sepsis/septic shock. Analysis
Statistical analyses were conducted using Stata version 11.2 (StataCorp, LP, College Station, TX). Statistical significance was set at P < 0.05. One member of the study team con ducted data extraction and statistical analyses. The Pearson x2 test was used to compare patient and operative characteristics www.spinejournal.com
1911
Spine
S urgery
Operating Microscopes During Spine Surgery • Basques et al
(9.4%) underwent surgery with the use of an operating microscope. A summary of patient demographics and comor bidities can be found in Table 1. The average age was 55.1 ± 14.4 years. Males comprised 51.6% of the cohort. Among all patients, 36.8% were ASA 3 to 4, and 43.5% had a modified CCI of 3 or greater. Comparison of patient characteristics using the Pearson \ 2 analysis found statistically significant differences between the microscope group and nonmicroscope group for age, BMI, modified CCI, and the number of levels. P values reported in Table 1 are for comparisons between all categories of each given demographic group. Patients undergoing spine surgery with the use a microscope were younger, had a lower BMI and modified CCI, and had fewer operative levels compared with the non microscope group. Although these differences were statistically significant, due to the relatively small magnitude of most differ ences, it is unclear if they were clinically significant. Nonethe less, these differences in patient and operative characteristics were controlled for in subsequent multivariate analyses.
between patients who underwent spine surgery with and without the use of an operating microscope. Operating room times were compared between microscope and nonmicroscope groups using bivariate and multivariate linear regression (as operating room times were treated as continuous variables), using nonmicroscope cases as the ref erence. Multivariate analysis adjusted for demographic and comorbidity variables (age, sex, BMI, ASA class, and modi fied CCI) and operative variables (number of levels and pro cedure type). Bivariate and multivariate logistic regressions were used to compare the rates of infections that occurred with or without the use of an operating microscope because infections were treated as binary variables.
RESULTS P a tie n t a n d O p e r a t iv e C h a ra c te ris tic s
A total of 23,670 elective spine procedures were identified in 2011 and 2012 in the ACS-NSQIP. A total of 2226 patients
Patient Characteristics
O verall, N o. (% )
All Patients
W ith o u t Microscope
W ith Microscope
2 3 ,6 7 0 (100)
2 1 ,4 4 4 (90.6)
2 2 2 6 (9.4)
0.002
A g e (yr) 1 5 -3 9
1 4 .8
1 4 .5
1 7 .2
4 0 -4 9
2 0 .8
2 0 .6
2 1 .9
5 0 -5 9
2 5 .7
2 5 .9
2 3 .9
6 0 -6 9
2 1 .2
2 1 .4
1 9 .8
>70
1 7 .5
1 7 .5
1 7 .2
M a le sex
5 1 .6
5 1 .6
5 1 .4
0 .8 2 8
0.033
B o d y m ass in d e x 1 8 -2 5
21 .1
1 0 .9
2 2 .7
2 5 -3 0
3 4 .7
3 4 .6
3 5 .9
3 0 -3 5
2 5 .3
2 5 .3
24 .1
>35
1 9 .0
1 9 .2
1 7 .4
ASA 3 -4
3 6 .8
35.1
3 7 .0
0 .0 7 8
0.001
M o d ifie d C C I 0 -1
3 3 .4
33.1
3 7 .0
2
2 3 .0
2 3 .2
2 1 .5
>3
4 3 .5
4 3 .7
4 1 .5
