Table 1 Distance of neurovascular structures from the borders of the low-risk zone.

From: Establishing a low-risk zone for a temporary extra-articular calcaneo-tibial pin fixation in an unstable ankle or subtalar joint

Slice number*

Low-risk zone

Tibial NV to most medial border

Sural N to lateral border

Tibial NV to medial border

Mean ± SD

Range

 

Mean ± SD

Range

95% CI

Mean ± SD

Range

95% CI

1

15.0 ± 2.5

9.1 − 21.1

14.7 − 15.6

12.8 ± 2.6

6.3 − 20.8

12.4 − 13.1

5.3 ± 2.2

0.5 – 12.4

5.0 – 5.6

2

13.9 ± 2.3

8.9 – 19.8

13.6 – 14.2

11.8 ± 2.6

5.7 – 19.9

11.5 – 12.2

4.1 ± 2.3

 − 1.12 – 11.3

3.8 – 4.4

3

12.6 ± 2.5

8.0 – 19.2

12.3 – 13.0

11.0 ± 2.7

5.2 – 17.7

10.7 –11.4

2.8 ± 2.6

 − 2.6 – 10.1

2.4 – 3.2

4

11.3 ± 2.5

6.4 – 17.2

11.0 – 11.7

10.2 ± 2.9

4.7 – 17.2

9.8 – 10.6

1.3 ± 2.9

 − 4.7 – 8.2

0.9 – 1.7

5

10.0 ± 2.7

2.9 – 16.3

9.6 – 10.4

9.2 ± 3.0

2.4 – 16.4

8.8 – 9.7

 −  2.2 ± 3.1

 − 6.8 – 7.7

 − 0.7 – 0.2

6

8.4 ± 2.8

2.4 – 15.4

8.0 – 8.8

8.1 ± 3.1

2.6 – 16.3

7.6 – 8.5

 − 2.0 ± 3.3

 − 8.4 – 6.7

 − 2.0 to − 1.5

  1. * T1 oblique axial slices were made with a thickness of 2 mm parallel to the trajectory of the pin fixation which was from the center of the calcaneal tuberosity to the to the distal tip of the posterior malleolus (slice 1). The values (mm) are presented as the mean with the standard deviation, range and 95% confidence interval. The negative ( −) values indicate that the neurovascular structures crossed the border. N nerve, NV neurovascular structure, SD standard deviation, CI confidence interval.
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