mi-tlif - effect of age, bmi& comorbidity - 2013-04-06 - global spine congress, hong kong
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MAST/MISS TLIFeffect of Age, BMI & Comorbidity in 200 patients
Petrus Stone, Neurosurgeon, Private PracticeBloemfontein, South Africa
2013-04-06
Disclosures
MAST/MISS Teaching on behalf of Medtronic
Sponsored attendance/travel
Study at my own expense
No animals were harmed
Literature
OPEN surgery Age – more
complicated BMI – more
complicated Comorbidity - more
complicated MI/MAST
Age – some studies BMI – some studies Co-morbidity – no
comparisons
Family debate– MISS Pros & Cons
Advantages (theoretical) Cosmesis, Pain, Hospital Stay, Blood Loss, Infection
Disadvantages (theoretical) Fusion Rate, Steep Learning Curve, Irradiation exposure
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)
Patients / Materials And Methods 200 consecutive degenerative TLIF
cases since 2009-08-31 Review case notes, hospital notes
(myself; senior 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 UFS statistician
Descriptive Stats – The Patients
Previous surgery Scar tissue: 23% Remove Ix: 3.5%
Age Frequency Percent CumulativeFrequency
CumulativePercent
<65 166 83.00 166 83.00
65-70 15 7.50 181 90.50
70-75 13 6.50 194 97.00
>75 6 3.00 200 100.00
BMI Frequency Percent CumulativeFrequency
CumulativePercent
<35 145 72.50 145 72.50
35-40 29 14.50 174 87.00
>40 26 13.00 200 100.00
ASA Frequency Percent CumulativeFrequency
CumulativePercent
1 53 26.50 53 26.50
2 88 44.00 141 70.50
3 59 29.50 200 100.00
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% B-F: 15.5%
3: 3.5% A: 2.5% B-F: 1.0%
Medtronic : n = 181 (90.5%) Navigation: n = 8 (4%) Radiation exposure: median 3.1
minutes
TLIF sub-classes to accommodate for extra work• a – no extra work• b – 30 minutes• c – 60 minutes• EtcExamples• Vertebroplasty; • adjacent level discectomy;• Same level wide decompression/lami;• Remove instrumentation
Descriptive Stats – Short term Outcome Duration follow up: 30-880
days Length of ICU/High Care
stay 0 nights: 14,5% 1 night: 75.5% 2 nights: 9.5%
Length of postoperative hospital stay Median 3.9 days (0.9 to
17.9) Need for transfusion
3.5%
Major• threatening to life or limb
function• Early revision surgeryModerate• prolonged hospital stay or
outpatient treatment requiredMinor• inconvenient
Significant ComplicationsModerate local complications %
durotomies 7.5%
superficial sepsis 1.0%
iatrogenic end plate damage --> extra screws 0.5%
partial L5 weakness 1 (0.5%) 0.5%
persisting dysesthetic leg pain 0.5%
plunge with PAK needle (uncomplicated) 0.5%
screw too deep, Hb drop 0.5%
11.0%
Major local complications %decompression same stay 1.0%fusion extension same stay 0.5%severe L4 nerve root damage 0.5% 2.0%
Major systemic complications %Pulmonary embolism 1.5%Unexpected epileptic fit 0.5%tachy-arythmia -> cardioversion 0.5% 2.5%
Moderate systemic complications %
respiratory (chest infection, atelectasis, sleep apnoea) 4.5%
arrhythmia 0.5%
quadriceps hematoma 0.5%
5.5%
Age effectWorse• Transfusion if >70:
15.8%• LOS if >70: 3.8 vs 3.9
vs 5.7 days• ICU stay (hours not
nights) if >65
Similar• Complications • Theater, Cutting,
Radiation time
Group name Age Group 2 Subgroup names <65 >65 Fisher’s Exact Test % % p-value Sig?Transfusion required 2.41 8.82 0.0969-Durotomy/CSF leak 6.63 11.76 0.2918-Local (major) 1.81 2.94 0.5284-Local (moderate) 9.64 17.65 0.2241-Local (minor) 0.60 0.00 1.0000-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-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-Local or Systemic (moderate) 14.46 26.47 0.1914-Local or Systemic (minor) 18.67 29.41 0.1577-Significant blood loss
ICU nights
1 night: 75.9%; 2 nights: 6.63% 1 night: 75.76%; 2
nights 24.24% 0.0005YesKruskal-Wallis Test Median Median p-value Sig?LOS postop (days) 3.80 4.90 0.0451YesTheater Time (hours) 4.10 4.30 0.4115-Cutting Time (hours) 3.00 3.10 0.5770-ICU stay (hours) 20.50 21.70 0.0020YesRadiation Exposure (mins) 3.10 3.10 0.6888-
BMI effect
Worse• ICU nights• Theater, Cutting, RE
time
Similar• Complications• Hospital LOS
Group name BMI BMI Group 3
Subgroup names <35 >35 <35 35-40 >40
Fisher’s Exact Test % % p-value % % % p-valueTransfusion 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 0.9088Local (major) 1.38 3.64 0.3038 1.38 6.90 0.00 0.1821Local (moderate) 12.41 7.27 0.4478 12.41 10.34 3.85 0.5757Local (minor) 0.00 1.82 0.2750 0.00 0.00 3.85 0.1300
Local (All: M, M, M) 13.79 12.73 0.1729 13.79 17.24 7.70 0.1149Systemic (major) 2.76 1.82 1.0000 2.76 0.00 3.85 0.6015Systemic (moderate) 4.83 7.27 0.4985 4.83 6.90 7.69 0.6770
Systemic (minor) 18.62 23.64 0.4338 18.62 24.14 23.08 0.6583
Systemic (all) 26.21 32.73 0.8746 26.21 31.04 34.62 0.9190Local or Systemic (major) 4.14 5.46 0.7084 4.14 6.90 3.85 0.8519Local or Systemic (moderate) 17.24 14.54 0.6623 17.24 17.24 11.54 0.9036
Local or Systemic (minor) 18.62 25.46 0.4338 18.62 24.14 26.93 0.6583ICU - zero nights 17.36 7.27
0.0381
17.36 13.79 0.00
0.0312ICU - one night 75.69 76.36 75.69 68.97 84.62
ICU - two night 6.94 16.36 6.94 17.24 15.38
ICU nights
Kruskal-Wallis Test median median p-value p-valueLOS postop (days) 3.90 4.00 0.1588 3.90 3.90 4.40 0.3392Theater Time (hours) 4.00 4.70 0.0209 4.00 4.60 5.20 0.0245Cutting 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
Comorbidity (ASA) effect
Summary
More likely• Minor & Moderate
systemic Cx• Theater & Cutting
time• ICU stay? (integar
nights; not hours)
Similar occurrence• Local Cx• Major Systemic Cx• Transfusion• ICU nights (hours
not nights)• LOS
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
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
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
Systemic (moderate) 1.89 6.82 6.78 0.4513 1.59 6.25 22.22 0.0491
Systemic (minor) 13.21 21.59 23.73 0.3462 11.11 22.66 44.44 0.0255
Systemic (all) 18.87 30.68 32.20 0.6372 15.87 31.25 66.66 0.0358
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
Local or Systemic (minor) 13.21 21.59 25.42 0.3462 11.11 23.44 44.44 0.0255
ICU - zero nights 26.42 12.64 6.780.0115
26.98 9.45 0.000.0034ICU - one night 66.04 81.61 76.27 66.67 81.10 66.67
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
Theater Time (hours) 3.60 4.20 4.70 0.0063 3.50 4.50 4.10 0.0008
Cutting Time (hours) 2.60 2.90 3.50 0.0153 2.40 3.30 2.90 0.0045
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
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