Introduction
Materials and methods
Ethics statement
Anaesthesia and peri-operative care
Behaviour evaluation
Vestibular function exploration using video-oculography
Statistical analysis
Surgical techniques
Unilateral labyrinthectomy (UL) step-by-step surgical technique
Unilateral vestibular neurectomy (UVN) step-by-step surgical technique
Results
UL and UVN clinical follow-up
Lesion | UL | UVN | p |
---|---|---|---|
Behavioural score | |||
Before | 0 | 0 | – |
Day 1 | 21.7 ± 1.2 | 21.3 ± 1.4 | 0.522 |
Day 4 | 11.5 ± 1.4 | 14.8 ± 0.8 | < 0.001 |
Day 7 | 7.2 ± 0.4 | 11.8 ± 1.2 | < 0.001 |
Day 28 | 5.0 ± 0.6 | 5.5 ± 0.5 | 0.339 |
Nystagmus count (beats per minute) | |||
Before | 0 | 0 | – |
Day 1 | 19 ± 11 | 31 ± 16 | 0.005 |
Day 4 | 12 ± 9 | 18 ± 12 | 0.161 |
Day 7 | 7 ± 2 | 9 ± 5 | 0.544 |
Day 28 | 5 ± 1 | 8 ± 3 | 0.746 |
UL and UVN functional follow-up
Frequency | 0.2 Hz | 0.5 Hz | 1 Hz | ||||||
---|---|---|---|---|---|---|---|---|---|
Lesion | UL | UVN | p | UL | UVN | p | UL | UVN | p |
aVOR gain | |||||||||
Before | 0.25 ± 0.09 | 0.35 ± 0.12 | 0.107 | 0.58 ± 0.15 | 0.60 ± 0.11 | 0.712 | 0.66 ± 0.17 | 0.74 ± 0.20 | 0.192 |
Day 1 | 0.04 ± 0.04 | 0.03 ± 0.02 | 0.865 | 0.09 ± 0.05 | 0.05 ± 0.03 | 0.570 | 0.17 ± 0.11 | 0.10 ± 0.07 | 0.294 |
Day 4 | 0.05 ± 0.05 | 0.07 ± 0.06 | 0.887 | 0.12 ± 0.07 | 0.16 ± 0.07 | 0.478 | 0.16 ± 0.07 | 0.29 ± 0.09 | 0.030 |
Day 7 | 0.12 ± 0.08 | 0.16 ± 0.12 | 0.514 | 0.27 ± 0.12 | 0.33 ± 0.16 | 0.364 | 0.42 ± 0.21 | 0.48 ± 0.18 | 0.335 |
Day 28 | 0.16 ± 0.06 | 0.20 ± 0.07 | 0.478 | 0.36 ± 0.13 | 0.37 ± 0.16 | 0.776 | 0.47 ± 0.16 | 0.49 ± 0.13 | 0.820 |
aVOR phase | |||||||||
Before | 29.3 ± 8.3 | 24.5 ± 10.6 | 0.649 | 9.9 ± 8.7 | 10.2 ± 3.9 | 0.982 | − 2.2 ± 4.3 | − 0.2 ± 3.6 | 0.855 |
Day 1* | – | – | – | – | – | – | – | – | – |
Day 4* | – | – | – | – | – | – | – | – | – |
Day 7 | 39.6 ± 9.4 | 31.8 ± 22.0 | 0.457 | 39.2 ± 25.6 | 23.1 ± 13.2 | 0.126 | 23.2 ± 14.6 | 16.0 ± 25.0 | 0.492 |
Day 28 | 43.6 ± 6.3 | 26.3 ± 41.9 | 0.102 | 27.9 ± 6.1 | 25.0 ± 11.4 | 0.393 | 5.8 ± 7.5 | 6.8 ± 4.4 | 0.925 |
Stimulation | Ipsilesional | Contralesional | ||||
---|---|---|---|---|---|---|
Lesion | UL | UVN | p | UL | UVN | p |
Static head tilt, slope* | ||||||
Before | 0.63 ± 0.24 | 0.67 ± 0.12 | 0.701 | 0.65 ± 0.25 | 0.62 ± 0.14 | 0.781 |
Day 1 | 0.16 ± 0.26 | 0.37 ± 0.27 | 0.053 | 0.57 ± 0.20 | 0.42 ± 0.28 | 0.169 |
Day 4 | 0.15 ± 0.11 | 0.28 ± 0.14 | 0.221 | 0.31 ± 0.28 | 0.34 ± 0.15 | 0.814 |
Day 7 | 0.19 ± 0.07 | 0.22 ± 0.12 | 0.811 | 0.41 ± 0.23 | 0.25 ± 0.18 | 0.144 |
Day 28 | 0.19 ± 0.14 | 0.34 ± 0.16 | 0.493 | 0.42 ± 0.14 | 0.47 ± 0.06 | 0.143 |
Off-vertical-axis rotation, MOR gain | ||||||
Before | 0.10 ± 0.07 | 0.12 ± 0.04 | 0.312 | 0.13 ± 0.07 | 0.10 ± 0.05 | 0.197 |
Day 1 | 0.02 ± 0.02 | 0.01 ± 0.01 | 0.274 | 0.02 ± 0.03 | 0.01 ± 0.02 | 0.292 |
Day 4 | 0.01 ± 0.03 | 0.02 ± 0.02 | 0.110 | 0.05 ± 0.08 | 0.03 ± 0.04 | 0.002 |
Day 7 | 0.00 ± 0.02 | 0.02 ± 0.04 | 0.222 | 0.04 ± 0.05 | 0.05 ± 0.02 | 0.702 |
Day 28 | 0.00 ± 0.01 | 0.01 ± 0.03 | 0.694 | 0.06 ± 0.03 | 0.09 ± 0.04 | 0.114 |
Angular velocity steps, time constant (seconds) | ||||||
Before | 3.69 ± 1.67 | 3.46 ± 1.27 | 0.690 | 4.01 ± 1.26 | 3.88 ± 1.97 | 0.826 |
Day 1 | 0.00 ± 0.00 | 0.00 ± 0.00 | 1 | 0.00 ± 0.00 | 0.00 ± 0.00 | 1 |
Day 4 | 0.22 ± 0.54 | 1.02 ± 1.35 | 0.176 | 1.19 ± 0.63 | 0.62 ± 0.91 | 0.336 |
Day 7 | 0.08 ± 0.15 | 1.11 ± 1.62 | 0.084 | 1.44 ± 1.24 | 1.77 ± 1.53 | 0.576 |
Day 28 | 1.21 ± 0.58 | 1.07 ± 1.20 | 0.807 | 2.52 ± 1.68 | 1.71 ± 0.43 | 0.170 |
Discussion
Lesion | UL | UVN |
---|---|---|
Surgical procedure length | Shortest (16 min)* | Longest (21 min)* |
Mouse survival rate | Satisfactory (86%)* | Poor (60%)* |
Cochlea | Intact | Destroyed |
Vestibular labyrinth | Destroyed | Intact |
Ganglion of Scarpa | Intact | Destroyed (suctioned) |
Type of lesion | Preganglionic lesion | Postganglionic lesion |
Degeneration of afferent fibres | No | Yes |
Behavioural score | Shorter recovery | Longer recovery |
Vestibular function | Similarly impaired | Similarly impaired |