Benchmarking of low back pain alleviation after TDA by surgeon and its
comparison to pain alleviation after ALIF
Aghayev E, Munting E, Röder C,
on behalf of the SWISSspine and Spine Tango registry groups
IEFM
Institute for Evaluative Research in Medicine
University of Bern
Background
In 2010 the Obama administration provided 1.1 billion USD for so-called “comparative
effectiveness research”.
On what level of the healthcare system can comparative effectiveness be analyzed? Therapies,
implants or healthcare providers are examples.
What should be measured?! „Treatment success“ (Outcome).
The “treatment success” may be influenced by a multitude of factors and is rarely clearly
defined.
Examples: achievement of minimum clinically relevant improvement, achievement of an
average improvement in an implant or surgeon group - the so-called benchmark.
Governmentally mandated national
HTA registry
Voluntary Eurospine
registry
ALIF
Total disc arthroplasty
degenerative disease
+ no previous surgery at the same level
+ retroperitoneal or transperitoneal anterior approach
+ anterior fusion between adjacent levels
+ rigid stabilization using a cage via anterior approach
- 534 patients (15 surgeons>10 cases)
- 50 patients (3 surgeons)
- only monosegmental
- only monosegmental
- 59% females
-78% females
- Ø age 42y (19-65ys)
- Ø age 46y (21-69ys)
Comparison of TDA and ALIF patients
Back pain
Group
N Ø Age (ys) Age range (ys) % female preop postop
Leg pain
Δ
preop postop
Quality of life
Δ
preop postop
Δ
TDA
534
42
19-65
59%
69
31
38
54
23
31 0.342 0.738 0.396
ALIF
50
46
21-69
78%
67
29
38
49
22
27
0.003*
n.v.
0.007*
0.20
0.54
0.85
0.19
0.87
Comparison (p-value) n.v.
n.v.
n.v.
n.v
0.36 n.v.
n.v.
n.v
The sole factor with an influence on back/leg pain and on quality of life improvement in the
SWISSspine registry is its preoperative level.
No significant influence: surgeon, implant, age, gender, FU time-point, depression, length of stay.
The following box plots show average pain alleviation or improvement of quality of life for each
individual implants and surgeons. Not adjusted and adjusted probabilities (by preoperative level) for
achievement of minimum clinically relevant change were calculated.
There were surgeons who had good patient selection, indicated by lower adjusted probabilities which
mean worsening of their outcomes if they had treated an average patient sample. The opposite
situation was with surgeons having higher adjusted probabilities indicative of lower preop pain values
in their patient sample compared with an average patient sample.
Influence of disc prosthesis on back pain
alleviation
‘green‘ – TDA prostheses, ‘blue‘ - ALIF
Probability for the achievement of minimum clinically relevant pain alleviation of 18 VAS points
Influence of disc prosthesis on leg pain alleviation
‘green‘ – TDA prostheses, ‘blue‘ - ALIF
Probability for the achievement of minimum clinically relevant pain alleviation of 18 VAS points
Influence of disc prosthesis on quality of life
improvement
TDA prostheses
Probability for the achievement of minimum clinically relevant improvement of 0.25 EQ-5D points
Influence of surgeon on back pain alleviation
‘green‘ – TDA prostheses, ‘blue‘ - ALIF
Probability for the achievement of minimum clinically relevant pain alleviation of 18 VAS points
Influence of surgeon on leg pain alleviation
‘green‘ – TDA prostheses, ‘blue‘ - ALIF
Probability for the achievement of minimum clinically relevant pain alleviation of 18 VAS points
Influence of surgeon on quality of life improvement
TDA surgeons
Probability for the achievement of minimum clinically relevant improvement of 0.25 EQ-5D points
Study limitations
- we studied three influential factors (surgeon, implant, procedure), thereby
adjusting for those co-variates that were available in the registry dataset. Other
co-variates with an influence may exist.
- a clear domination of both types of pain may often not be given. Some
patients may be treated for high preoperative back pain levels with low or no
preoperative leg pain, which may have led to good probabilities for back pain
MCRPI but low ones for leg pain.
Conclusions
- the influence of disc prosthesis and surgeon is not significant (the only significant covariates are preoperative pain levels and quality of life)
- despite insignificance, there are visible (clinically relevant?!) variations in pain alleviation
and in improvement of quality of life between different surgeons
- the analysis confirms that selection/indication criteria may be at least one of the causes of
the different outcomes
- surgeons with the best outcome may help to improve the quality of indications by
presenting their selection criteria to their peers.
None of the authors has any potential conflict of interest.
Acknowledgment: We would like to thank the SWISSspine and Spine Tango registry groups who made this research possible by
populating the database with their valuable and much appreciated entries. The analysed data were recorded by (in alphabetic
order): Aebi M, Bärlocher C, Baur M, Berlemann U, Binggeli R, Boos N, Cathrein P, Etter C, Faundez A, Favre J, Forster T, Grob
D, Hasdemir M, Hausmann O, Heilbronner Raoul, Heini P, Huber J, Jeanneret B, Kast E, Kleinstueck F, Kroeber M, Lattig F, Lutz
T, Maestretti G, Marchesi D, Markwalder T, Martinez R, Min K, Morard M, Otten P, Porchet F, Ramadan A, Renella R, Richter H,
Rischke B, Schaeren S, Schizas C, Schwarzenbach O, Seidel U, Selz T, Sgier F, Stoll TM, Tessitore E, Van Domelen K, Vernet
O, Wernli FO, Waelchli B.