Quantitative measures of performance in microvascular anastomoses

Figures & data

Figure 1. Left: Standard microsurgical tools equipped with trackable marker arrays (during a rat microvascular anastomosis). Right: Marker array equipped with retro-reflective markers attached to forceps handle.

Figure 2. Microvascular anastomosis hierarchical decomposition.

Figure 3. Data formatting steps.

Table I.  Kinematic performance measure definitions.

Performance measure	Definition
Time	Start and stop times evaluated using archived video data.
	Task	Start/stop definition
	Needle placement	Start: needle tip touches tissue
		Stop: needle tip through tissue
	Knot throw	Start: grasping of the suture
		Stop: release of the suture
	Free space movement	Time period outside of the needle placement and knot throw
Tool tip trajectory distance	Length of the trajectory followed by the tool tip for a particular task or subtask.
Tool tip excursion distance	Instantaneous straight-line distance from the localized surgical worksite to the tool tip.
Tool tip velocity	Instantaneous tool tip velocity

Figure 4. A: A comparison of CPD functions of any arbitrary performance measure using the K–S statistic. B: Bootstrapping approach based on resampling of two finite sets. C: Using the CPD of D from resampling to establish confidence bounds on D.

Table II.  Summary of tool tracking and anastomosis results.

				Acquired data during manipulation (%)
Procedure (Days)	Vessel	Operative time* (min)	Number of placed sutures	Left	Right	Patency
1 (1)	Right femoral	27.1	7	93.5	89.2	Yes
2 (1)	Left femoral	26.8	6	84.5	84.5	Yes
3 (1)	Right carotid	25.4	7	85.7	88.7	Yes
4 (1)	Left carotid	20.5	7	96.4	92.4	Yes
5 (2)	Right femoral	30.9	6	94.5	94.2	Yes
6 (2)	Left femoral	28.4	7	96.1	92.3	Yes
7 (2)	Right carotid	31.4	7	85.4	91.7	Yes
8 (2)	Left carotid	22.7	6	94.1	83.1	Yes
9**	Right femoral	24.6	6	–	–	Yes
10**	Left femoral	25.9	6	–	–	Yes

*Operative time measured from the initial vessel incision until removal of the support clamp.

**Procedures conducted without marker arrays attached to the tools.

Figure 5. Sample of a three-dimensional tool tip trajectory (left) and a tool tip excursion profile (right) for a knot-throwing subtask.

Figure 6. Performance measure results for an experienced surgeon. The error bars represent the plus or minus standard deviation.

Figure 7. K–S difference statistic of performance measures for the right and left tools at the subtask level. The confidence intervals marked indicate a 90% confidence bound and are based on a bootstrap estimate.