Review of effect of Age, Morbid Obesity & Medical Comorbidity upon sshort term outcome after minimally invasive TLIF procedure

1. MAST/MISS TLIF
effect of Age, BMI & Comorbidity in 200 patients
Petrus Stone, Neurosurgeon, Bloemfontein
2012-10-06

2. Disclosures
 MAST/MISS
Teaching on behalf
of Medtronic
 No funding/
compensation for
this study or
presentation
 No animals were
harmed

3. Background - Motivation for study
 Expected small
incisions to be like
tips of iceberg i.e.
pretty on the surface
but …
 Unexpectedly plain
sailing (anaesthesia
& hospital) for older
& sicker patients
 Quantify this
suspicion

4. Literature
 OPEN surgery
 Age – more
complicated
 BMI – more
complicated
 Comorbidity - more
complicated
 MI/MAST
 Age – some studies (Mendeley Group: TLIF)
 BMI – some studies
 Co-morbidity – no
comparisons

5. Family debate– open vs MISS
 Advantages (theoretical)
 Cosmesis,
 Pain,
 Hospital Stay,
 Blood Loss,
 Infection
 Disadvantages (theoretical)
 Fusion Rate,
 Steep Learning Curve,
 Irradiation exposure

6. Objective
 To what degree does
co-morbidity affect
(short term) outcome
 Use of Information
 Patient/procedure
selection
 Resource allocation
(length of stay, High
Care nights,
transfusion,
Physicians)

7. Patients / Materials And
Methods
 200 consecutive degenerative TLIF
cases since 2009-08-31
 Review case notes, hospital notes
(myself; Mediclinic nurse)
 Excluded 6 cases
 1x conversion to open
 1x aborted procedure (revision of
open TLIF; screw holes too big)
 1x cancellation on table (medical
aid interference)
 3 trauma thoraco-lumbar cases
 Stat analysis by UOFS statistician

9. Descriptive Stats – The Procedures
 Surgical Time
 Median 3 hours (1h25-9h30) (case
no 9; 3 levels)
 Levels operated / Orange River TLIF
Class
 1: 56.5%
 A: 39%
 B-F: 15%
 2: 40%
 A: 24.5%
TLIF sub-classes to accommodate for extra
 B-F: 15.5%
work
 3: 3.5% • a – no extra work
 A: 2.5% • b – 30 minutes
• c – 60 minutes
 B-F: 1.0% • Etc
 Medtronic : n = 181 (90.5%) Examples
• Vertebroplasty;
 Navigation: n = 8 (4%) • adjacent level discectomy;
 Radiation exposure: median 3.1 • Same level wide decompression/lami;
minutes (range 1.5 to 23) • Remove instrumentation

10. Descriptive Stats – Short term Outcome
Major  Duration follow up: 30-880
• threatening to life or limb days
function
• Early revision surgery  Length of ICU/High Care
Moderate stay
• prolonged hospital stay or  0 nights: 14,5%
outpatient treatment required
Minor  1 night: 75.5%
• inconvenient  2 nights: 9.5%
 Length of postoperative
hospital stay
 Median 3.9 days (0.9 to
17.9)
 Need for transfusion
 3.5%

11. Significant Complications
Major local complications % Major systemic complications %
decompression same stay 1.0% Pulmonary embolism 1.5%
fusion extension same stay 0.5% Unexpected epileptic fit 0.5%
severe L4 nerve root damage 0.5% tachy-arythmia -> cardioversion 0.5%
2.0% 2.5%
Moderate local complications %
Moderate systemic complications %
durotomies 7.5%
superficial sepsis 1.0% respiratory (chest infection, atelectasis,
iatrogenic end plate damage --> extra screws 0.5% sleep apnoea) 4.5%
partial L5 weakness 1 (0.5%) 0.5%
persisting dysesthetic leg pain 0.5% arrhythmia 0.5%
plunge with PAK needle (uncomplicated) 0.5%
screw too deep, Hb drop 0.5% quadriceps hematoma 0.5%
11.0%
5.5%
Summary all significant complications %
Complications (Major/moderate; Systemic/Local) 21.0%
Cases (Major and/or Moderate) 18.5%

12. Significant Complications
Major local complications %
decompression same stay 1.0%
fusion extension same stay 0.5%
severe L4 nerve root damage 0.5%
2.0%

13. Outcomes/Effects of:
Age
BMI
Comorbidity

14. Age effect
Group name Age Group 2
Subgroup names <65 >65
Fisher’s Exact Test % % p-value Sig? Worse
Transfusion required 2.41 8.82 0.0969 - • Transfusion if >70:
Durotomy/CSF leak
Local (major)
6.63
1.81
11.76 0.2918 -
2.94 0.5284 -
15.8%
Local (moderate) 9.64 17.65 0.2241 - • LOS if >70: 3.8 vs
Local (minor) 0.60 0.00 1.0000 - 3.9 vs 5.7 days
• ICU stay (hours not
Local (All: M, M, M) 12.05 20.59 0.4077 -
Systemic (major) 2.41 2.94 1.0000 -
Systemic (moderate) 4.82 8.82 0.4028 - nights) if >65
Systemic (minor) 18.07 29.41 0.1577 -
Systemic (all) 25.30 41.17 0.1415 -
Local or Systemic (major) 4.22 5.88 0.6515 - Similar
Local or Systemic (moderate) 14.46 26.47 0.1914 - • Complications
Local or Systemic (minor) 18.67 29.41 0.1577 -
• Theater, Cutting,
Significant blood loss
1 night: 75.9%; 2
1 night: 75.76%; 2
Radiation time
nights: 6.63%
ICU nights nights 24.24% 0.0005 Yes
Kruskal-Wallis Test Median Median p-value Sig?
LOS postop (days) 3.80 4.90 0.0451 Yes
Theater Time (hours) 4.10 4.30 0.4115 -
Cutting Time (hours) 3.00 3.10 0.5770 -
ICU stay (hours) 20.50 21.70 0.0020 Yes
Radiation Exposure (mins) 3.10 3.10 0.6888 -

15. BMI effect
Group name BMI BMI Group 3
Subgroup names <35 >35 <35 35-40 >40
Fisher’s Exact Test % % p-value % % % p-value
Transfusion required 3.45 3.64 1.0000 3.45 0.00 7.69 0.2114
Durotomy/CSF leak 8.28 5.45 0.7642 8.28 6.90 3.85 0.9088
Local (major) 1.38 3.64 0.3038 1.38 6.90 0.00 0.1821 Worse
• ICU nights
Local (moderate) 12.41 7.27 0.4478 12.41 10.34 3.85 0.5757
Local (minor) 0.00 1.82 0.2750 0.00 0.00 3.85 0.1300
• Theater, Cutting, RE
Local (All: M, M, M) 13.79 12.73 0.1729 13.79 17.24 7.70 0.1149
Systemic (major) 2.76 1.82 1.0000 2.76 0.00 3.85 0.6015
Systemic (moderate)
Systemic (minor)
4.83
18.62
7.27
23.64
0.4985 4.83 6.90 7.69 0.6770
0.4338 18.62 24.14 23.08 0.6583
time
Systemic (all) 26.21 32.73 0.8746 26.21 31.04 34.62 0.9190
Local or Systemic (major) 4.14 5.46 0.7084 4.14 6.90 3.85 0.8519
Local or Systemic
(moderate) 17.24 14.54 0.6623 17.24 17.24 11.54 0.9036
Similar
Local or Systemic (minor)
ICU - zero nights
18.62
17.36
25.46
7.27
0.4338 18.62 24.14 26.93 0.6583
17.36 13.79 0.00
• Complications
ICU - one night 75.69 76.36 0.0381 75.69 68.97 84.62 0.0312
6.94 17.24 15.38
• Hospital LOS
ICU - two night 6.94 16.36
ICU nights
Kruskal-Wallis Test median median p-value p-value
LOS postop (days) 3.90 4.00 0.1588 3.90 3.90 4.40 0.3392
Theater Time (hours) 4.00 4.70 0.0209 4.00 4.60 5.20 0.0245
Cutting Time (hours) 2.80 3.50 0.0163 2.80 3.20 3.80 0.0216
ICU stay (hours) 21.00 22.00 0.1765 21.00 20.40 23.00 0.1687
Radiation Exposure (mins) 3.00 3.70 0.0153 3.00 3.00 5.30 0.0012

16. Comorbidity (ASA) effect
Group name ASA score ASA_Ex_BMI
Subgroup names ASA 1 ASA 2 ASA 3 ASA 1 ASA 2 ASA 3
Fisher’s Exact Test % % % p-value % % % p-value
Transfusion required 1.89 4.55 3.39 0.8867 1.59 4.69 0.00 0.5883
Durotomy/CSF leak 9.43 7.95 5.08 0.6999 7.94 7.81 0.00 1.0000
Local (major) 0.00 2.27 3.39 0.5810 0.00 3.13 0.00 0.4221 Summary
Local (moderate) 15.09 11.36 6.78 0.3714 14.29 10.16 0.00 0.5071
Local (minor) 0.00 0.00 1.69 0.5600 0.00 0.78 0.00 1.0000
More likely
Local (All: M, M, M) 15.09 13.63 11.86 0.4548 14.29 14.07 0.00 0.6124
Systemic (major) 3.77 2.27 1.69 0.7278 3.17 2.34 0.00 0.7349 • Minor & Moderate
Systemic (moderate) 1.89 6.82 6.78 0.4513 1.59 6.25 22.22 0.0491 systemic Cx
Systemic (minor) 13.21 21.59 23.73 0.3462 11.11 22.66 44.44 0.0255 • Theater & Cutting
Systemic (all) 18.87 30.68 32.20 0.6372 15.87 31.25 66.66 0.0358
time
Local or Systemic (major) 3.77 4.54 5.08 1.0000 3.17 5.47 0.00 0.8168
Local or Systemic (moderate) 16.98 18.18 13.56 0.6589 15.88 16.41 22.22 0.7344
• ICU stay? (integar
Local or Systemic (minor) 13.21 21.59 25.42 0.3462 11.11 23.44 44.44 0.0255 nights; not hours)
ICU - zero nights 26.42 12.64 6.78 26.98 9.45 0.00
ICU - one night 66.04 81.61 76.27 0.0115 66.67 81.10 66.67 0.0034
Similar occurrence
• Local Cx
ICU - two night 7.55 5.75 16.95 6.35 9.45 33.33
Kruskal-Wallis Test median median median p-value p-value
LOS postop (days) 3.80 3.90 4.00 0.2550 3.60 4.00 4.00 0.0857 • Major Systemic Cx
Theater Time (hours) 3.60 4.20 4.70 0.0063 3.50 4.50 4.10 0.0008 • Transfusion
Cutting Time (hours) 2.60 2.90 3.50 0.0153 2.40 3.30 2.90 0.0045 • ICU nights (hours
not nights)
ICU stay (hours) 20.20 21.10 22.00 0.1933 20.20 21.10 25.20 0.0362
Radiation Exposure (mins) 2.90 3.00 3.70 0.0509 2.90 3.30 2.90 0.1182
• LOS

17. Gender effect
Group name Gender
Summary
Subgroup names Female Male
Fisher’s Exact Test % % p
Transfusion required 2.65 4.60 0.4713 Worse
Durotomy/CSF leak 7.08 8.05 0.7939 • LOS: 4.1 vs 3.7 days
Local (major) 1.77 2.30 1.0000 • Radiation exposure: 2.5 vs 2.9
Local (moderate) 11.50 10.34 0.8243
Local (minor) 0.88 0.00 1.0000
minutes
Local (All: M, M, M) 14.15 12.64 0.9635
Systemic (major) 2.65 2.30 1.0000 Similar
Systemic (moderate) 5.31 5.75 1.0000 • Complications
Systemic (minor) 23.01 16.09 0.2851
Systemic (all) 30.97 24.14 0.6038
• Theater/Cutting time
Local or Systemic (major) 4.42 4.60 1.0000 • ICU/High care use
Local or Systemic (moderate) 16.81 16.09 1.0000
Local or Systemic (minor) 23.89 16.09 0.2851
ICU - zero nights 10.62 19.77
ICU - one night 79.65 70.93 0.2075
ICU - two night 9.73 9.30
Kruskal-Wallis Test mean mean p
LOS postop (days) 4.10 3.70 0.0028
Theater Time (hours) 4.30 4.00 0.2124
Cutting Time (hours) 3.20 2.90 0.2744
ICU stay (hours) 21.50 19.90 0.1832
Radiation Exposure (mins) 3.50 2.90 0.0395

18. Revision effect
Group name Revision Surgery
Group values De Novo Scar Ix
Fisher’s Exact Test p-value significance % % %
Transfusion required 0.1926 - 2.72 4.35 14.29
Durotomy/CSF leak 0.0038 Yes 4.08 19.57 0.00
Local (major) 1.0000 - 2.04 2.17 0.00
Local (moderate) 0.0080 Yes 6.80 23.91 14.29
Local (minor) 1.0000 - 0.68 0.00 0.00
Local (All: M, M, M) 0.0421 Yes 9.52 26.08 14.29
Worse
Systemic (major) 0.0573 - 1.36 4.35 14.29
• Durotomy
Systemic (moderate) 0.5293 - 4.76 8.70 0.00
Systemic (minor) 0.4722 - 18.37 26.09 14.29
• Theater time (but not
Systemic (all) 0.1817 - 24.49 39.14 28.58 cutting time)
Local or Systemic (major) 0.1580 - 3.40 6.52 14.29 Similar
Local or Systemic (moderate) 0.0068 Yes 11.56 32.61 14.29 • Cutting time (? Numbers)
Local or Systemic (minor) 0.4722 - 18.37 26.09 14.29 • Transfusion requirements
ICU nights 0.8029 - • Systemic complications
Group values De Novo Scar Ix De Novo Other local Ix
• Scar complications
Kruskal-Wallis Test p-value sig? median1 median2 median3 LOS mean2
•mean1 mean3
LOS postop (days) 0.4061 - 3.80 4.00 3.90
• 4.6ICU stay (hours & nights)
5 5.2
Theater Time (hours) 0.0071 Yes 4.00 4.40 5.80 4.2 4.7 5.8
Cutting Time (hours) 0.0800 - 2.90 3.30 4.70 3.1 3.5 4.1
ICU stay (hours) 0.6516 - 21.20 21.00 19.60 23 20.9 20
Radiation Exposure (mins) 0.1912 - 3.00 3.80 3.50 4.1 4.4 3.9

19. Levels operated
Group name Levels
Worse
Subgroup names 1 level 2 level 3 level
Fisher’s Exact Test p-value sig? % % %
• Durotomies
Transfusion required 0.1012 - 1.77 5.00 14.29 • ((Theater, Cutting, Radiation
Durotomy/CSF leak 0.0315 Yes 3.54 12.50 14.29 time))
Local (major) 0.1582 - 1.77 1.25 14.29
• LOS & ICU stay
Local (moderate) 0.0019 Yes 4.42 20.00 14.29
Local (minor) 0.435 - 0.00 1.25 0.00
Local (All: M, M, M) 0.0015 Yes 6.19 22.50 28.58 Same
Systemic (major) 0.7082 - 1.77 3.75 0.00 • Systemic complications
Systemic (moderate) 0.2784 - 3.54 8.75 0.00
• Local complications except
Systemic (minor) 0.5822 - 17.70 22.50 28.57
Systemic (all) 0.535 - 23.01 35.00 28.57 durotomy
Local or Systemic (major) 0.3304 - 3.54 5.00 14.29
Local or Systemic (moderate) 0.0025 Yes 7.96 28.75 14.29
Local or Systemic (minor) 0.5822 - 17.70 23.75 28.57
ICU nights 0.0001 Yes
Kruskal-Wallis Test Median Median Median
LOS postop (days) 0.0229 Yes 3.70 4.70 4.70
Theater Time (hours) 0.0001 Yes 3.20 5.00 6.50
Cutting Time (hours) 0.0001 Yes 2.20 3.80 5.20
ICU stay (hours) 0.0071 Yes 20.30 21.40 21.20
Radiation Exposure (mins) 0.0001 Yes 2.70 3.70 5.50

20. More complex surgery (n = 125)
Group name Orange River TLIF class (n = 125)
Subgroup names 1a 1b 1c 1d 2a 2b 2c 2d 3a 3c
Fisher’s Exact Test p-value (Chi-Square) sig? % % % % % % % % % %
Local or Systemic (major) 0.5377 (Chi-Square) - 8.2 6.7 0.0 0.0 2.9 9.1 16.7 50.0 0.0 0.0
Local or Systemic (moderate) 0.3234 (Chi-Square) - 4.1 26.7 33.3 0.0 11.8 18.2 0.0 0.0 0.0 0.0
Local or Systemic (minor) 0.3831 (Chi-Square) - 12.2 13.3 0.0 0.0 8.8 9.1 16.7 0.0 0.0 100.0
Significant blood loss 0.0032 (Chi-Square) yes 4.1 40.0 0.0 50.0 35.3 18.2 50.0 50.0 0.0 100.0
LOS postop (days) 0.0389 (Kruskal-Wallis Test) yes 3.7 4.5 3.9 3.1 4.5 6.6 4.9 5.7 6.3 5.7

21. Application- using probabilities &
median values
S3977 S4073 S4095
Age 30 53 70
BMI 38 33
Comorbidity (ASA) 1 1 2
Gender Female Male Female
Previous surgery Scar (laminectomy None Instrumentation L4-S1
same level)
Transitional vertebra no lumbarized S1 (work no
higher up though)
Plan L5/S1 TLIF & IX L5/6 TLIF & Ix L3/4 TLIF, wide
dekompression,
remove some of L4-S1
Ix; consider
vertebroplasty
Orange Class 1a 1a 1d
Bottom line: S3977 S4073 S4095
Prepare theater time 4.1 3.0 6.2
Prepare 2 nights in ICU/High Care 14.3% 12.6% 31.4%
Prepare physician due to
major/moderate systemic
complications 52.0% 43.4% 74.4%
Prepare transfusion 15.2% 15.6% 31.2%

22. Summary
 Age
 >70: longer LOS (4 vs 6 days)
 >70: transfusion more likely
(15 vs 2%)
 >65: ICU stay (hours not
nights)
 ISQ complications
 BMI
 Longer procedure, theater
time, irradiation time
 More ICU nights
 ISQ complications & LOS
 Comorbidity (ASA score)
 Longer procedure
 ISQ complications & LOS