Potential Roles of Teamwork and Unmet Needs on Surgical Learning Curves of Spinal Robotic Screw Placement

Figures & data

Figure 1 Timeline of robotic spine surgery at Kaohsiung Medical University Hospital (KMUH). The orthopedic surgeons joined the robotic spine surgery team in August 2014. At that time, 255 cases and 1237 screws had been placed successfully. (NS: cases performed by neurosurgeons).

Table 1 Characteristics of Patients in Three Groups

	NS Early-50 (2013–2014)	Ortho Early-50 (2014–2015)	NS Later-50 (2014–2015)	P value
Case No.	50	50	50
Age (yrs)				0.4677***
mean±SD	64.1±16.4	61.3±18.4	65.0±9.4
Sex				0.1451**
Male/Female	17/33	20/30	11/39
BMI (kg/m^2)				0.4703***
mean±SD	25.1±3.1	24.8±3.4	25.8±5.0
Segments				<0.0001**
2 levels (≦4 screws)	30	8	38
3 levels (6 screws)	13	23	11
>3 levels (>6screws)	7	19	1
No. of Screws	254	363	224
Time/screw (min)				0.0017*
mean±SD	9.56±4.19	7.29±3.64	8.74±5.77
Accuracy
Overall screws	99.6% (253/254)	99.5% (361/363)	99.1% (222/224)
By cases:				0.7735**
100%	49	48	49
<100%	1	2	1

Notes: Italicized values indicate P<0.05.

Abbreviations: NS, neurosurgery; Ortho, orthopedic surgery; *, test by Wilcoxon sign rank test; **, test by chi-squared test; ***, test by ANOVA; SD, standard deviation; BMI, body mass index.

Figure 2 Groups learning curves. The learning curve of the 3 groups and the test of parallelism were plotted. The upper part (A) is the curves of the 3 groups put combined. The lower part of the figure (B) is the curve for each group. The parallelism of these curves was tested using the parallelism F-test and showed no significance.

Table 2 Time per Screw and Learning Curve Between 5 Doctors

Surgeons/Years of Practice	Year of Robotic Spine Surgery	Case No.	Screws	Time/Screw (Min) Mean ± SD	Growth Rate Estimate ± SE
Dr. A/26 yrs	May, 2013-Jun, 2013	10	40	12.28±5.21*	−0.13±0.17**
Dr. B/22 yrs	Sep, 2013-Nov, 2014	10	40	6.38±1.54	0.08±0.92
Dr. C/15 yrs	Sep, 2014-Jun, 2015	10	40	8.68±3.10	−1.41±0.0
Dr. D/11 yrs	Apr, 2014-Jun, 2017	10	40	6.33±1.90	−0.57±1.6
Dr. E/22 yrs	Aug, 2014-Jun, 2016	10	40	6.73±1.81	0.75±0.0
		p-value		0.001*	<0.0001**

Abbreviations: SD, standard deviation; SE, standard error; *, test by Wilcoxon sign rank test; **, test by parallelism F-test.

Figure 3 Individual surgeon’s learning curve. The learning curves of individual surgeons and the test of parallelism were plotted. The right side of the figure is the curve for each surgeon. The left side is the curves of the 5 surgeons combined. The parallelism of these curves, tested using the parallelism F-test, showed a significant difference among the curves.