Biomechanical Mapping of the Vagina - Tactile Imaging · 2019-02-02 · ISCG World Congress...

ISCG World Congress Orlando, FL, January 29-30, 2019

Biomechanical Mapping of the VaginaVladimir Egorov, Ph.D.

Advanced Tactile Imaging, Inc.1457 Lower Ferry RDTrenton, NJ 08618, USA


Leaning Objectives

1. Soft tissue elasticity

2. Biomechanical mapping

3. Biomechanical characterization of the vagina and pelvic floor

4. Clinical results: reproducibility, laser and RF treatments


Introduction

Increasingly, laser or radiofrequency (RF) treatment technologies, aesthetic or cosmetic procedures are being used for vaginal modification.

However, no reliable tools and techniques exist for objective assessment of vaginal biomechanical conditions before and after the applied treatment.

AIM: To develop a new approach for quantitative biomechanical assessment of the vagina.


Tissue Elasticity

In mechanics [1], elasticity is the ability of a material (1) to resist applied stress, and (2) to return to its original shape when the stress is removed.

Elasticity moduli characterize the ability to resist the applied stress as an intrinsic property of the specific material [1, 2].

In the case of linear deformation of uniform object, Young’s modulus = Force/Compression = Stress/Strain. It is the Hooke’s law.

The stress to strain ratio directly characterizes the soft tissue elasticity.

Definitions

1. Timoshenko S, Goodier JN. Theory of Elasticity. New York: McGraw-Hill Book Company; 1951: 1-508.2. Landau LD, Lipshitz EM. Theory of Elasticity, 3rd Edition, 1970: 1-172.

Figure 1. Force vs Compression.


Definitions


FUNCTIONAL TACTILE IMAGING translates muscle activity into dynamic pressure pattern P(x,y,t), where t is time and x,y are coordinates where pressure P was measured. It may include: muscle voluntary contraction, reflex contraction, relaxation, specific maneuvers [4].

Definitions

4. Lucente V, van Raalte H, Murphy M, Egorov V. Biomechanical paradigm and interpretation of female pelvic floor conditions before a treatment. InternationalJournal of Women's Health 2017;9: 521-550.


Tactile Imaging Functional Tactile Imaging

Definitions

• Tissue elasticity distribution• Anatomical features• Vaginal tightening • Pelvic support conditions

• Pelvic muscles contractive strength • Muscle anatomical features• Structure mobility• Involuntary muscle relaxation

Biomechanical Mapping


Methods

Figure 3. Vaginal tactile imaging (VTI) probe during examination.

Probe with 96 pressure sensors (48 sensors per side with sensor step of 2.5 mm)

Pressure sensitive surface

Anterior compartment

Posterior compartment

Pubic bone


Methods

Figure 4. VTI probe insertion to deform vaginal walls by a definitive manner; (A) - a tactile image and (B) - with calculatedgradients for VTI probe insertion for a 37 y.o. woman with normal pelvic floor conditions.

The VTI software automatically calculates for this test:

1. Maximum resistance force to insertion [N],2. Insertion work [mJ], and3. Maximum stress-to-strain ratio [kPa/mm] (tissue elasticity)


Methods

Figure 5. VTI probe 360o rotation at Test 2 (A) and circumferential tactile image for a 49 y.o. woman with normal pelvic floor support (B).

The VTI software automatically calculates for this test:

1. Maximum intravaginal pressure [kPa],2. Anterior vs posterior force [N], and3. Left vs right force [N].


Methods

Figure 6. Voluntary muscle contraction) results for a 62 y.o. patient with normal pelvic floor support. A, D – anterior and posterior pressure patterns at muscle contraction (red lines) and at rest (light brown lines); B, E – dynamic pressure pattern along the vagina;

C, F – muscle contraction dynamic at specific locations (see dotted lines in B, E).

0 31 kPa

Pressure scale

0 31 kPaPressure scale

A B C

D E F

Urethra

Pubic bone

Puboperineal muscle

Puborectal muscle

Puborectal muscle contraction

Muscle vibration

Puboperineal muscle contraction

Puboperineal muscle contraction

Muscle desynchronization

Pubovaginal muscle


Methods

Studied Population

• We analyzed 42 subjects with normal pelvic floor conditions (no pelvic organ prolapse) from an observational case-controlled clinical study (NCT02294383 at http://clinicaltrials.gov).

• The average subject age was 52, with their individual ages ranging from 26 to 90 years.


Results

ICC=0.91 ICC=0.89

Figure 7. Intra-observer reproducibility.The range is from 0.80 to 0.92

Average value = 0.87 [5]

Figure 8. Inter-observer reproducibility.The range is from 0.73 to 0.92

Average value = 0.82 [5]

5. van Raalte H, Lucente V, Ephrain S, Murphy M, Bhatia N, Sarvazyan N, Egorov V. Intra- and inter-observer reproducibility of vaginal tactile imaging. Female PelvicMedicine & Reconstructive Surgery 2016; 22(5S): S130-131.


Results

Figure 9. VTI parameters 1-8 vs subject age (brown dots/trendlines – nulliparous; blue – parous). Egorov et al, Sexual Medicine, 2018 .

A B C

A - maximum resistance force to insertion [N]B - insertion work [mJ]C - maximum stress/train ratio [kPa/mm]

D

E F HG

D - maximum intravaginal pressure [kPa]E - anterior vs posterior force [N]F - left vs right force [N]

G – maximum pressure at pelvic muscle contraction [kPa]

H - muscle contraction force [N]


ResultsTable 1. Studied characteristics and VTI parameters [6].

Age, years old

Weight, lb Resistance, N Work, mJ

Stress-to strain,

kPa/mm

Pressure at rest, kPa

Anterior-posterior force, N

Left-right force, N

Contraction pressure, kPa

Contraction force, N

Mean value 52.7 152.6 1.09 41.3 1.94 26.8 1.66 0.98 41.8 3.20

Correlation (R) with age - - -0.36 -0.48 -0.26 -0.28 -0.40 -0.54 -0.32 -0.36

T-test (age≤52 vs >52; p-value) - - 0.007 0.002 0.05 0.23 0.04 0.005 0.20 0.05

Correlation (R) with weight - - -0.12 -0.10 -0.19 -0.24 -0.05 0.05 -0.05 -0.06

T-test (weight≤152 vs >152; p-value) - - 0.99 0.91 0.64 0.37 0.94 0.74 0.53 0.38

T-test (nulliparous vs parous; p-value) - - 0.05 0.10 0.10 0.30 0.06 0.02 0.04 0.27

6. Egorov V, Murphy M, Lucente V, van Raalte H, Ephrain S, Bhatia N, Sarvazyan N. Quantitative assessment and interpretation of vaginal conditions. Sexual Medicine 2018; 6(1): 39-48.


Results

No. Parameter Before After Laser Treatment

1 Maximum Resistance [N] 0.23 1.45

2 Insertion Work [mJ] 4.5 53.4

3 Maximum Gradient (tissue elasticity) [kPa/mm] 0.67 3.73

BEFORE AFTER 2nd Laser Treatment

Results for a 61 y.o. patient with normal pelvic floor support [7]

7. van Raalte H, Bhatia N, Egorov V. Is it all just smoke and mirrors?: Vaginal laser therapy and its assessment by tactile imaging. International Urogynecology Journal2016; 27 (S1): S120-121.


Results

Clinical results [8] for Dynamic Quadripolar Radiofrequency (DQRF) vaginal therapy [9]

8. Bensmail H. Evolutions in diagnosis and treatment of vaginal laxity. EC Gynaecology 2018; 7(8): 321-327.

9. Vicariotto F and Raichi M. Technological evolution in the radiofrequency treatment of vaginal laxity and menopausal vulvo-vaginal atrophy and othergenitourinary symptoms: first experiences with a novel dynamic quadripolar device. Minerva Ginecologica 2016; 68(3): 225‐236.


Conclusions

Biomechanical mapping of the vagina allows :

1) Characterization of the ‘normal’ vaginal conditions,

2) Quantification of the deviations from normality, and

3) Assessment of the applied treatment.


Thank you for your attention!

The research was supported in a part by the National Institute on Aging, USA; Grant SB1AG034714 Vaginal Tactile Imager for Pelvic Floor Biomechanical Assessment

Acknowledgements

Biomechanical Mapping of the Vagina - Tactile Imaging · 2019-02-02 · ISCG World Congress...

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