Unilateral perineural anaesthesia on the lame leg facilitates the selection of z bar shoeing technique for the treatment of navicular syndrome

Figures & data

Figure 1. The creation of z bar shoe to fit the affected limbs of the horses. The z bar shoe is created by cutting unilateral branch of metal shoe and connecting the cut branch with the intact branch by another piece of metal to produce a non-weight-bearing area (a). The affected palmar region is rasped more than another part of foot to create the non-weight-bearing area and facilitate hoof wall growth (red arrow) (b). Non-weight-bearing positions on medial side of left and right forelimbs fitted with z bar shoes respectively (c and d).

Figure 2. The application of z bar shoes on the affected limbs of the horses. The horse no. 1 (a) and no. 3 (b) are shod with medial palmar non-weight bearing z bar shoe on the right forelimb. The horse no. 2 (c) are shod on the left forelimb with lateral palmar non-weight bearing Z bar shoe, while the horse no. 4 (d) and no. 5 (e) are shod on the left forelimb with medial palmar non-weight-bearing z bar shoes. LF; left forelimb, RF; right forelimb.

Table 1. Clinical examination of horses with chronic foot pain performed by the application of hoof tester, extension test, flexion test, wedge test, and regional anaesthesia.

Lameness examination
Horses	Limbs	Lameness score	Hoof tester	Extension test	Flexion test	Wedge test
1	RF	2	sm^+	++ve	+ve	+ve
2	LF	3	sl^+	++ve	+ve	+ve
3	RF	3	sm^+	+ve	+ve	+ve
4	LF	2	ns	+ve	+ve	+ve
5	LF	3	sm+	++ve	++ve	+ve
Perineural anaesthesia
Horses	Limbs	Lameness score	Lameness score after perineural nerve block^a
			Palmar digital nerve block		Abaxial nerve block
			Medial	Lateral	Medial	Lateral
1	RF	2	0	-n-	-n-	-n-
2	LF	3	3	1	1	0
3	RF	3	1	1	0	-n-
4	LF	2	1	1	0	-n-
5	LF	3	1	1	0	-n-

Notes: RF = right forelimb, LF = left forelimb, sm⁺ = most sensitive on medial palmar region, sl⁺ = most sensitive on lateral palmar region, ns = insensitive to compression, +ve = slight increase in the lameness score after trotting off compared to their own score, ++ve = marked increase in the lameness score after trotting off compared to their own score, and -n- = not performed.

^aThe horses were trotted off after unilateral perineural nerve block starting from the medial side.

Figure 3. Lameness scores from gait analyses of each horse before shoeing, and 5 min, 2, 4, and 8 weeks after shoeing with z bar shoe. *p < .05, significantly different from lameness score before shoeing, **p < .01, significantly different from lameness score before shoeing.