analysis of learning curve for minimally invasive transforaminal lumbar interbody fusion byung-joon...
TRANSCRIPT
Analysis of Learning Curve for Minimally Invasive Transforaminal
Lumbar Interbody Fusion
Byung-Joon Shin, Jae Chul Lee, Hae-Dong Chang,
Su-Jin Yun, Yon-Il Kim
Spine Center
Department of Orthopaedic Surgery
Soonchunhyang University Hospital
Seoul, Korea
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
¬ Minimally Invasive TLIF• Advantages
– Decreased soft tissue injury
• Unilateral exposure & less muscle dissection
• Preservation of contralateral structure
– Decreased operative bleeding
• Disadvantages– Technically demanding
– Increased operative time
Introduction
Steep learning curve
Peng et al., Spine, 2009; Scheufler et al., Neurosurg, 2007; Schizas, Int Orthop, 2008
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
¬ ‘New’ vs. ‘Gold standard’ procedure
A. False negative result– Too early assessment
B. Indifferent result
C. Positive result
Introduction
New
Old(Gold standard)
Ramsay CR et al: Statistical assessment of the learning curves of health technologies.
Health Technol Assess 5:1–79, 2001
Learning curve
for MIS TLIF?
When?
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
¬ Prospective analysis of • The first 41 cases of MIS TLIF
procedure• Degenerative lumbar disease treated
by– Decompression thru tubular retractor
– Obliquely inserted a PEEK cage
– Percutaneous pedicle screw fixation and fusion
• F/U > minimum 1yr
Materials
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
¬ Patients characteristics• Average age: 57 yrs (36-76)• Average F/U: 21 m• Etiology
– Spinal stenosis: 24 cases– Spondylolisthsis: 12 cases– HIVD: 3 cases– IDD: 1 case– Seg. Instability: 1 case
Materials
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
¬ Procedure (41 patients)• No. of operated levels
– 1 level TLIF: 31 cases– 1 level TLIF + 1 level decomp: 8 cases– 2 level TLIF: 2 cases
Materials
• Laminectomy– Unilateral: 37 cases– Bilateral: 4 cases
• Contralateral decompression– 16 cases
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
Methods¬ Assessing parameters of learning curve
• Length of operative time• Amount of bleeding
• Intraoperative bleeding• H-vac drain• Total perioperative bleeding
• Starting day of ambulation• Transfusion incidence• Occurrence of complications
¬ Clinical outcome• Oswestry disability index• Visual analogue scale
– Low back pain– Radiating pain to legs
Learning curve
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
Statistical analysis¬ Regression analysis for learning curve
• Bivariate analysis• Case # vs. parameters (operative time,
bleeding)• Logarithmic curve-fit
¬ Former 20 vs. Latter 21 cases• Student T-test
• Operative time, Blood loss, Start of ambulation
• Chi-square test• Transfusion need, Occurrence of
complications
¬ SPSS (ver.13.0)• p<0.05
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
Results ¬ Operative time (F/U > 1yr; n=41)
Case #
Min
p=0.000*
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
Results ¬ Operative time (Whole series; 72 cases)
Case #
Min
Asymptote
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
Results ¬ Operative time
p=0.000
*
*
Mean Op. Time
Case #1-20 249
Case #21-41 198
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
Results ¬ Operative time
**
P < 0.05*
§
§ P > 0.05
198185
Mean Op.
Time
Case #1-20 250
Case #21-41 198
Case #42-72 185
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
Results ¬ Intraoperative Bleeding
ml
Case #
p=0.005*
Amount of Bleeding
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
Results ¬ Postoperative H-vac Drain
ml
Case #
p=0.547§
Amount of Bleeding
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
Results ¬ Perioperative Blood Loss (Intraop + Drain)
ml
Case #
p=0.004*
Amount of Bleeding
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
Results ¬ Amount of Bleeding
** p=0.190§
§
p=0.000*
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
Results ¬ Start of ambulation
p=0.000*
X 1
X 13
X 6
X 2
X 17
X 2
Case# 1-20 Case# 21-41
PO Day
Ambulation
Case #1-20 2.8±0.6
Case #21-41 2.0±0.5
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
Results ¬ Transfusion incidence
p=0.009*
Yes No
Case #1-20 6 14
Case #21-41 0 21
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
Results ¬ Occurrence of Complications
Case #
#10: Deep infection
#24: Bone graft frag. extrusion from the cage
#25: Screw malposition
#41: Minimal dural tear
Yes
No
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
Results ¬ Oswestry Disability Index
ODI
PreOp. 24
Final 7
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
Results ¬ VAS for Low Back Pain
LBP
PreOp. 5.1
Final 1.7
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
Results ¬ VAS for Radiating Pain to Legs
RP
PreOp. 6.9
Final 0.8
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
Results ¬ Case #1-20 versus Case #21-41
*
*
*P<0.05*
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
Summary and Conclusions¬ Learning curve for minimally invasive TLIF was
steep, but acceptable. Asymptote of the curve was approximately 35-40 cases.
¬ Operative time was significantly decreased with a surgeon’s experience.
Mean Op. time
Case #1-20 249 min
Case #21-41 198 min
Learning curve for MIS TLIF
SCH spine center
Oct 15, 2009
Summary and Conclusions¬ Amount of bleeding and needs for transfusion
also significantly decreased with a learning curve.
¬ Minimally invasive TLIF can be an effective method treating degenerative lumbar diseases, provided appropriate training is obtained.
Intraop.Bleeding Perioperative B
Case #1-20 506 ml 689 ml
Case #21-41 272 ml 382 ml
Thank you very much.