Table 1.
VTI Biomechanical Parameters.
| No. | VTI Test |
Parameters Abbreviation |
Units | Parameter Description | Parameter Interpretation | Parameter Class | Targeting/Contributing Pelvic Structures |
|---|---|---|---|---|---|---|---|
| 1 | 1 | Fmax | N | Maximum value of force measured during the VTI probe insertion [9] | Maximum resistance of anterior vs posterior widening; tissue elasticity at specified location (capability to resist to applied deformation) | Maximum vaginal tissue elasticity at specified location | Tissues behind the anterior and posterior vaginal walls at 3–15 mm depth |
| 2 | 1 | Work | mJ | Work completed during the probe insertion (Work = Force × Displacement) [9] | Integral resistance of vaginal tissue (anterior and posterior) along the probe insertion | Average vaginal tissue elasticity | Tissues behind the anterior and posterior vaginal walls at 3–15 mm depth |
| 3 | 1 | Gmax_a | kPa/mm | Maximum value of anterior gradient (change of pressure per anterior wall displacement in orthogonal direction to the vaginal channel) | Maximum value of tissue elasticity in anterior compartment behind the vaginal at specified location | Maximum value of anterior tissue elasticity | Tissues/structures in anterior compartment at 10–15 mm depth |
| 4 | 1 | Gmax_p | kPa/mm | Maximum value of posterior gradient (change of pressure per posterior wall displacement in orthogonal direction to the vaginal channel) | Maximum value of tissue elasticity in posterior compartment behind the vaginal at specified location | Maximum value of posterior tissue elasticity | Tissues/structures in anterior compartment at 10–15 mm depth |
| 5 | 1 | Pmax_a | kPa | Maximum value of pressure per anterior wall along the vagina | Maximum resistance of anterior tissue to vaginal wall deformation | Anterior tissue elasticity | Tissues/structures in anterior compartment |
| 6 | 1 | Pmax_p | kPa | Maximum value of pressure per posterior wall along the vagina | Maximum resistance of posterior tissue to vaginal wall deformation | Posterior tissue elasticity | Tissues/structures in posterior compartment |
| 7 | 2 | P1max_a | kPa | Maximum pressure at the area of pubic bone (anterior, A1 in Figure 2) | Proximity of pubic bone to vaginal wall and perineal body strength | Anatomic aspects and tissue elasticity | Tissues between vagina and pubic bone; perineal body |
| 8 | 2 | P2max_a | kPa | Maximum pressure at the area of urethra (anterior, A2 in Figure 2) | Elasticity/mobility of urethra | Anatomic aspects and tissue elasticity | Urethra and surrounding tissues |
| 9 | 2 | P3max_a | kPa | Maximum pressure at the cervix area (anterior, A3 in Figure 2) | Mobility of uterus and conditions of uterosacral and cardinal ligaments | Pelvic floor support | Uterosacral and cardinal ligaments |
| 10 | 2 | P1max_p | kPa | Maximum pressure at the perineal body (posterioir, see P1 in Figure 2) | Pressure feedback of Level III support | Pelvic floor support | Puboperineal, puborectal muscles |
| 11 | 2 | P2max_p | kPa | Maximum pressure at middle third of vagina (posterioir, see P2 in Figure 2) | Pressure feedback of Level II support | Pelvic floor support | Pubovaginal, puboanal muscles |
| 12 | 2 | P3max_p | kPa | Maximum pressure at upper third of vagina (posterioir, see P3 in Figure 2) | Pressure feedback of Level I support | Pelvic floor support | Iliococcygeal muscle, levator plate |
| 13 | 2 | G1max_a | kPa/mm | Maximum gradient at the area of pubic bone (anterior, see A1 in Figure 2) | Vaginal elasticity at pubic bone area | Anterior tissue elasticity | Tissues between vagina and pubic bone; perineal body |
| 14 | 2 | G2max_a | kPa/mm | Maximum gradient at the area of urethra (anterior, see A2 in Figure 2) | Mobility and elasticity of urethra | Urethral tissue elasticity | Urethra and surrounding tissues |
| 15 | 2 | G3max_a | kPa/mm | Maximum gradient at the cervix area (anterior, see A3 in Figure 2) | Conditions of uterosacral and cardinal ligaments | Pelvic floor support | Uterosacral and cardinal ligaments |
| 16 | 2 | G1max_p | kPa/mm | Maximum gradient at the perineal body (posterioir, see P1 in Figure 2) | Strength of Level III support (tissue deformation up to 25 mm) | Pelvic floor support | Puboperineal, puborectal muscles |
| 17 | 2 | G2max_p | kPa/mm | Maximum gradient at middle third of vagina (posterioir, see P2 in Figure 2) | Strength of Level II support (tissue deformation up to 35 mm) | Pelvic floor support | Pubovaginal, puboanal muscles |
| 18 | 2 | G3max_p | kPa/mm | Maximum gradient at upper third of vagina (posterioir, see P3 in Figure 2) | Strength of Level I support (tissue deformation up to 45 mm) | Pelvic floor support | Iliococcygeal muscle, levator plate |
| 19 | 3 | Pmax | kPa | Maximum pressure at vaginal walls deformation by 7 mm [9] | Hard tissue or tight vagina | Vaginal tissue elasticity | Tissues behind the vaginal walls at 5–7 mm depth |
| 20 | 3 | Fap | N | Force applied by anterior and posterior compartments to the probe [9]. | Integral strength of anterior and posterior compartments | Vaginal tightening | Tissues behind anterior/ posterior vaginal walls. |
| 21 | 3 | Fs | N | Force applied by entire left and right sides of vagina to the probe [9]. | Integral strength of left and right sides of vagina | Vaginal tightening | Vaginal right/left walls and tissues behind them. |
| 22 | 3 | P1_l | kPa | Pressure response from a selected location (irregularity 1) at left side (see S1 in Figure 2) | Hard tissue on left vaginal wall | Irregularity on vaginal wall | Tissue/muscle behind the vaginal walls on left side. |
| 23 | 3 | P2_l | kPa | Pressure response from a selected location (irregularity 2) at left side (see S2 in Figure 2) | Hard tissue on left vaginal wall | Irregularity on vaginal wall | Tissue/muscle behind the vaginal walls on left side. |
| 24 | 3 | P3_r | kPa | Pressure response from a selected location (irregularity 3) at right side (see S1 in Figure 2) | Hard tissue on right vaginal wall | Irregularity on vaginal wall | Tissue/muscle behind the vaginal walls on right side. |
| 25 | 4 | dF_a | N | Integral force change in anterior compartment at Valsalva maneuver | Pelvic function* at Valsalva maneuver | Pelvic function | Multiple pelvic muscle* |
| 26 | 4 | dPmax_a | kPa | Maximum pressure change in anterior compartment at Valsalva maneuver. | Pelvic function* at Valsalva maneuver | Pelvic function | Multiple pelvic muscle* |
| 27 | 4 | dL_a | mm | Displacement of the maximum pressure peak in anterior compartment | Mobility of anterior structures* Valsalva maneuver | Pelvic function | Urethra, pubovaginal muscle; ligaments* |
| 28 | 4 | dF_p | N | Integral force change in posterior compartment at Valsalva maneuver | Pelvic function* at Valsalva maneuver | Pelvic function | Multiple pelvic muscle* |
| 29 | 4 | dPmax_p | kPa | Maximum pressure change in posterior compartment at Valsalva maneuver. | Pelvic function* at Valsalva maneuver | Pelvic function | Multiple pelvic muscle* |
| 30 | 4 | dL_p | mm | Displacement of the maximum pressure peak in posterior compartment | Mobility of posterioir structures* Valsalva maneuver | Pelvic function | Anorectal, puborectal, pubovaginal muscles; ligaments* |
| 31 | 5 | dF_a | N | Integral force change in anterior compartment at voluntary muscle contraction | Integral contraction strength of pelvic muscles along the vagina | Pelvic function | Puboperineal, puborectal, pubovaginal and ilicoccygeal muscles; uretra |
| 32 | 5 | dPmax_a | kPa | Maximum pressure change in anterior compartment at voluntary muscle contraction | Contraction strength of specified pelvic muscles | Pelvic function | Puboperineal, puborectal and pubovaginal muscles |
| 33 | 5 | Pmax_a | kPa | Maximum pressure value in anterior compartment at voluntary muscle contraction. | Static and dynamic peak support of the pelvic floor | Pelvic function | Puboperineal and puborectal muscles* |
| 34 | 5 | dF_p | N | Integral force change in posterior compartment at voluntary muscle contraction | Integral contraction strength of pelvic muscles along the vagina | Pelvic function | Puboperineal, puborectal, pubovaginal and ilicoccygeal muscles |
| 35 | 5 | dPmax_p | kPa | Maximum pressure change in posterior compartment at voluntary muscle contraction | Contraction strength of pelvic muscles at specified location | Pelvic function | Puboperineal, puborectal and pubovaginal muscles |
| 36 | 5 | Pmax_p | kPa | Maximum pressure value in posterior compartment at voluntary muscle contraction. | Static and dynamic peak support of the pelvic floor | Pelvic function | Puboperineal and puborectal muscles* |
| 37 | 6 | dF_r | N | Integral force change in right side at voluntary muscle contraction | Integral contraction strength of pelvic muscles along the vagina | Pelvic function | Puboperineal, puborectal, and pubovaginal muscles |
| 38 | 6 | dPmax_r | kPa | Maximum pressure change in right side at voluntary muscle contraction | Contraction strength of specific pelvic muscle | Pelvic function | Puboperineal or puborectal or pubovaginal muscles |
| 39 | 6 | Pmaxa_r | kPa | Maximum pressure value in right side at voluntary muscle contraction | Specified pelvic muscle contractive capability and integrity | Pelvic function | Puboperineal or puborectal muscles |
| 40 | 6 | dF_l | N | Integral force change in left side at voluntary muscle contraction | Integral contraction strength of pelvic muscles along the vagina | Pelvic function | Puboperineal, puborectal, and pubovaginal muscles |
| 41 | 6 | dPmax_l | kPa | Maximum pressure change in left side at voluntary muscle contraction | Contraction strength of specific pelvic muscle | Pelvic function | Puboperineal or puborectal or pubovaginal muscles |
| 42 | 6 | Pmaxa_l | kPa | Maximum pressure value in left side at voluntary muscle contraction | Specified pelvic muscle contractive capability and integrity | Pelvic function | Puboperineal or puborectal muscles |
| 43 | 7 | dPdt_a | kPa/s | Anterior absolute pressure change per second for maximum pressure at involuntary relaxation | Innervation status of specified pelvic muscles | Innervations status | Levator ani muscles |
| 44 | 7 | dPcdt_a | %/s | Anterior relative pressure change per second for maximum pressure at involuntary relaxation | Innervation status of specified pelvic muscles | Innervations status | Levator ani muscles |
| 45 | 7 | dPdt_p | kPa/s | Posterior absolute pressure change per second for maximum pressure at involuntary relaxation | Innervation status of specified pelvic muscles | Innervations status | Levator ani muscles |
| 46 | 7 | dPcdt_p | %/s | Posterior relative pressure change per second for maximum pressure at involuntary relaxation | Innervation status of specified pelvic muscles | Innervations status | Levator ani muscles |
| 47 | 8 | dF_a | N | Integral force change in anterior compartment at reflex pelvic muscle contraction (cough) | Integral pelvic function* at reflex muscle contraction | Pelvic function | Multiple pelvic muscle* |
| 48 | 8 | dPmax_a | kPa | Maximum pressure change in anterior compartment at reflex pelvic muscle contraction (cough). | Contraction strength of specified pelvic muscles | Pelvic function | Multiple pelvic muscle* |
| 49 | 8 | dL_a | mm | Displacement of the maximum pressure peak in anterior compartment | Mobility of anterior structures* at reflex muscle contraction | Pelvic function | Urethra, pubovaginal muscle; ligaments* |
| 50 | 8 | dF_p | N | Integral force change in posterior compartment at reflex pelvic muscle contraction (cough) | Integral pelvic function* at reflex muscle contraction | Pelvic function | Multiple pelvic muscle* |
| 51 | 8 | dPmax_p | kPa | Maximum pressure change in posterior compartment at reflex pelvic muscle contraction (cough). | Contraction strength of specified pelvic muscles | Pelvic function | Multiple pelvic muscle* |
| 52 | 8 | dL_p | mm | Displacement of the maximum pressure peak in posterior compartment | Mobility of anterior structures* at reflex muscle contraction | Pelvic function | Anorectal, puborectal and pubovaginal muscles; ligaments* |
*
requires further interpretation