Therapeutic Validation of Venous Pulsatile Tinnitus and Biomaterial Applications for Temporal Bone Reconstruction Surgery Using Multi-sensing Platforms and Coupled Computational Techniques

Abstract

The application of grafts and biomaterials is a cardinal therapeutic procedure to resolve venous pulsatile tinnitus (PT) caused by temporal bone dehiscence during transtemporal reconstructive surgery. However, the transmission mechanism of venous PT remains unclear, and the sound absorption and insulation properties of different repair materials have not been specified. This study quantifies the vibroacoustic characteristics of PT, sources the major transmission pathway of PT, and verifies the therapeutic effect of different material applications using joint multi-sensing platforms and coupled computational fluid dynamics (CFD) techniques. The in vivo intraoperative acoustic and vibroacoustic characteristics of intrasinus blood flow motion and dehiscent sigmoid plate of a typical venous PT patient were investigated using acoustic and displacement sensors. The acoustical, morphological, and mechanical properties of the dehiscent sigmoid plate, grafts harvested from a cadaveric head, and other biomaterials were acquired using acoustical impedance tubes, micro-CT, scanning electron microscopy, and mercury porosimetry, as appropriate. To analyze the therapeutic effect of our previous reconstructive techniques, coupled CFD simulations were performed using the acquired mechanical properties of biomaterials and patient-specific radiologic data. The peak in vivo intraoperatively gauged, peak simulated vibroacoustic and peak simulated hydroacoustic amplitude of PT prior to sigmoid plate reconstruction were 64.0, 70.4, and 72.8 dB, respectively. After the solidified gelatin sponge–bone wax repair technique, the intraoperative gauged peak amplitude of PT was reduced from 64.0 to 47.3 dB. Among three different reconstructive techniques based on CFD results, the vibroacoustic and hydroacoustic sounds were reduced to 65.9 and 68.6 dB (temporalis–cartilage technique), 63.5 and 63.1 dB (solidified gelatin sponge technique), and 42.4 and 39.2 dB (solidified gelatin sponge–bone wax technique). In conclusion, the current novel biosensing applications and coupled CFD techniques indicate that the sensation of PT correlates with the motion and impact from venous flow, causing vibroacoustic and hydroacoustic sources that transmit via the air-conduction transmission pathway. The transtemporal reconstructive surgical efficacy depends on the established areal density of applied grafts and/or biomaterials, in which the total transmission loss of PT should surpass the amplitude of the measured loudness of PT.

Retroauricular/Transcranial Color-Coded Doppler Ultrasound Approach in Junction With Ipsilateral Neck Compression on Real-Time Hydroacoustic Variation of Venous Pulsatile Tinnitus

“…From the presence to the disappearance of PT, it is postulatsed that this quantitative range of flow velocity reduction offers a bottom-line curative marker for both extraluminal compression and endoluminal surgeries. However, the former surgical technique conceivably requires less flow velocity reduction due to the thickening of the soundproof sigmoid wall, although the compression depth of the transverse–sigmoid junction ought to be performed with circumspection to prevent the iatrogenic cause of intracranial pressure ( Hsieh et al, 2022 ; Qiu et al, 2022 ). A recent clinical study revealed that sinus flow velocity is reduced after a lumbar puncture without a concomitant reduction in the bulk flow rate, resulting in a 3.8 ± 3.4 improvement of PT intensity on a 0–10 Likert scale in 10 subjects ( Haraldsson et al, 2019 ).…”

“…Previous computational studies found that the flow-induced displacement of the vascular wall could generate vibro-acoustic noise from 48.76 to 116.57 dB ( Tian et al, 2017 ; Mu et al, 2021a , b ). The amplitude of the vibro-acoustic sound surpassed that of the hydroacoustic source when the volume and surface contributions were juxtaposed ( Hsieh et al, 2022 ). Nevertheless, based on intraoperative measurements, the frequency of vascular displacement was below the hearing threshold ( Hsieh et al, 2022 ).…”

“…The amplitude of the vibro-acoustic sound surpassed that of the hydroacoustic source when the volume and surface contributions were juxtaposed ( Hsieh et al, 2022 ). Nevertheless, based on intraoperative measurements, the frequency of vascular displacement was below the hearing threshold ( Hsieh et al, 2022 ). It remains unclear whether the vibro-acoustic sound is generated solely from the vibration of the sigmoid sinus wall.…”

Time Series and Mel-frequency Cepstrum Coefficient Analyses of Venous Pulsatile Tinnitus Vascular Sound and Flow Velocity Sensed by Transcranial/Retroauricular Doppler Ultrasound Approaches

“…According to previous computational studies, reducing the fluctuation of the flow velocity alleviates the wall pressure induced by the fluid-structure interaction and reduces the vibroacoustic component of PT. (6,15) Thus, if surgical reduction of the flow velocity is prioritized, the endoluminal stenting technique may be more suitable than the transtemporal technique since expanding the sinus lumen endoluminally is less likely to perniciously augment the intracranial pressure. (7,16,17) In contrast to transverse sinus stenting, using the transtemporal compression technique to reduce the flow velocity should prevent overcompressing the sinus lumen to avoid the iatrogenic cause of intracranial hypertension.…”

“…(9) Therefore, the degree of reduction of flow velocity and the patency of collateral sinuses should be carefully measured prior to surgical intervention. Since the surgical repair of dehiscence using robust biomaterials provides a therapeutic effect in alleviating PT, (15) the external compression technique can be performed as an additional or alternative method if addressing dehiscence alone fails to preclude PT. (10) Further studies on the range of velocity reduction and its surgical indication to eliminate PT are warranted.…”