Temporal bone contrast-enhanced high-resolution CT evaluation of pulsatile tinnitus after sigmoid sinus wall reconstruction

Morphological remodeling of the repaired sigmoid sinus bone wall in patients with pulsatile tinnitus after successful surgical reconstruction: an ultra-high-resolution CT study

BACKGROUND

Sigmoid sinus wall reconstruction (SSWR) is an effective treatment for pulsatile tinnitus (PT). However, follow-up postoperative imaging manifestations have not been extensively reported.

PURPOSE

To evaluate the morphological changes in patients with PT after successful SSWR using ultra-high-resolution computed tomography (U-HRCT).

MATERIAL AND METHODS

Data were retrospectively analyzed from 10 patients with PT who underwent successful SSWR primarily with autologous bone powder. U-HRCT scans were performed within 3 days of surgery and repeated 6 months later. The integrity, relative density, extent, and shape of the repaired wall were analyzed. The chi-square test was used to compare the categorical variables and the Phi (φ) coefficient was used to represent the magnitude of the correlation.

RESULTS

Among the 10 patients with PT, 1 (10%) achieved complete coverage of the defect with the residual bone, 8 (80%) had partial coverage, and 1 (10%) showed complete separation. A gap between the repaired wall and residual bone in the initial U-HRCT was linked to incomplete defect coverage in the subsequent U-HRCT scan (P < 0.001, φ = 0.903). The repaired wall shrank from the periphery to the center and the density increased. The repaired wall compressed into the sigmoid sinus retracts over time, reshaping into a naturally curved sigmoid sinus sulcus.

CONCLUSION

Morphological remodeling is a typical characteristic of the repaired sigmoid sinus wall in patients with PT. Short-term incomplete repair may imply incomplete coverage of the defect in the future, but this is not correlated with recurrence.

Fluid-structure interaction study on the causes of mending material damage after sigmoid sinus wall reconstruction

BACKGROUND AND OBJECTIVE

Sigmoid Sinus (SS) Wall Reconstruction (SSWR) is the mainstream treatment for pulsatile tinnitus (PT), but it has a high risk of recurrence. The damage of mending material is the key cause of recurrence, and its hemodynamic mechanism is still unclear. The purpose of this study was to investigate the hemodynamic causes of mending material breakage.

METHODS

In this study, six patient-specific geometric models were reconstructed based on the data of the computed tomography angiography (CTA). The transient fluid-structure coupling method was performed to clarify the hemodynamic state of sigmoid sinus and the biomechanical state of the mending material. The distribution of stress and displacement and the flow pattern were calculated to evaluate the hemodynamic and biomechanics difference at the mending material area.

RESULTS

The area of blood flow impact in some patients (2/6) was consistent with the damaged location of the mending material. The average stress (6/6) and average displacement (6/6) of damaged mending material were higher than those of complete mending material. All (6/6) patients showed that the high-stress and high-displacement proportion of the DMM region was higher than that of the CMM region. Moreover, the average stress fluctuation (6/6) and average displacement (6/6) fluctuation degree of damaged mending material is larger than that of complete mending material.

CONCLUSIONS

The impact of blood and the uneven stress and displacement fluctuation of the mending material may be the causes of mending material damage. High stress and high displacement might be the key causes of the mending material damage.

Multiphysics Interaction Analysis of the Therapeutic Effects of the Sigmoid Sinus Wall Reconstruction in Patients with Venous Pulsatile Tinnitus

Sigmoid sinus wall dehiscence (SSWD) is an important etiology of venous pulsatile tinnitus (VPT) and is treated by sigmoid sinus wall reconstruction (SSWR). This study aimed to investigate the therapeutic effects of the different degrees of SSWR and the prognostic effect in patients with VPT. Personalized models of three patients with SSWD (control), 3/4SSWD, 1/2SSWD, 1/4SSWD, and 0SSWD were reconstructed. A multiphysics interaction approach was applied to elucidate the biomechanical and acoustic changes. Results revealed that after SSWR, the average pressure of venous vessel on the SSWD region reduced by 33.70 ± 12.53%, 35.86 ± 12.39%, and 39.70 ± 12.45% (mean ± SD) in three patients with 3/4SSWD, 1/2SSWD, and 1/4SSWD. The maximum displacement of the SSWR region reduced by 25.91 ± 30.20%, 37.20 ± 31.47%, 52.60 ± 34.66%, and 79.35 ± 18.13% (mean ± SD) in three patients with 3/4SSWD, 1/2SSWD, 1/4SSWD, and 0SSWD, with a magnitude approximately 10^-3 times that of the venous vessel in the SSWD region. The sound pressure level at the tympanum reduced by 23.72 ± 1.91%, 31.03 ± 14.40%, 45.62 ± 19.11%, and 128.46 ± 15.46% (mean ± SD). The SSWR region was still loaded with high stress in comparison to the surrounding region. The SSWR region of the temporal bone effectively shielded the high wall pressure and blocked the transmission of venous vessel vibration to the inner ear. Patients with inadequate SSWR still had residual VPT symptoms despite the remission of VPT symptoms. Complete SSWR could completely solve VPT issues. High-stress distribution of the SSWR region may be the cause of the recurrence of VPT symptoms.

Dynamic Volume Computed Tomography for Characterizing Pulsatile Tinnitus Caused by Sigmoid Sinus Diverticulum with Bone Defects: Clinical Implications

OBJECTIVE

The objective of this study is to investigate the diagnosis of dynamic volume computed tomography (CT) for pulsatile tinnitus caused by sigmoid sinus diverticulum (SSD) and bone defects.

METHODS

Data obtained by dynamic volume CT from 35 patients with SSD were retrospectively collected. Then the ear morphological parameters, including bone defect, transverse sinus stenosis, position of the jugular bulb, jugular bulb diverticulum, defect of the jugular bulb wall, gross venous sinus thrombosis and SSD, and blood perfusion parameters, including cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT), were evaluated and compared between the tinnitus side and the asymptomatic side of the ear.

RESULTS

The maximum diameters of the bone defects on the tinnitus side were greater than those on the asymptomatic side (Horizontal 6.36±2.35mm vs. 1.12±0.78mm; Longitudinal 4.87±1.25 vs. 0.88±0.06mm). Dynamic volume CT visually displayed the SSD herniated into the adjacent mastoid via the bone defect. Transverse sinus stenosis, high position of the jugular bulb, jugular bulb diverticulum, defect of the jugular bulb wall, and gross venous sinus thrombosis were present more frequently on the tinnitus side than on the asymptomatic side (P < 0.05). Moreover, CBF, CBV, and MTT were significantly greater on the tinnitus side than on the asymptomatic side (P < 0.05).

CONCLUSION

Dynamic volume CT examination is an effective method for the diagnosis of pulsatile tinnitus caused by SSD with bone defects.

Multiphysics coupling numerical simulation of flow-diverting stents in the treatment of patients with pulsatile tinnitus

Patients with pulsatile tinnitus (PT) have unstable treatment effects after resurfacing surgery. Flow-diverting stents (FDS) are proposed as a potential method for the treatment of PT, but the therapeutic effect is not clear. This study aimed to investigate the efficacy of FDS in the treatment of patients with PT induced by sigmoid sinus diverticulum (SSD) and sigmoid sinus wall dehiscence (SSWD). In addition, we aimed to explore the treatment mechanism of PT. Transient-state multiphysics coupling numerical simulation method based on computed tomography angiography of five patients was used to clarify the biomechanical and acoustic states before and after FDS placement. FDS was placed to prevent the blood flow from impacting the vessel wall in the SSD and SSWD areas. Low blood flow velocity (<0.0391 m/s), high relative residence time (>10 Pa^-1 ), and low wall shear stress of SSD might lead to thrombosis after FDS placement. The average pressure on the SSWD area of each patient decreased by 13.77%, 18.82%, 29.23%, 19.03%, and 11.20%. The average displacement of the vessel wall on the SSWD area showed acute pulsation and decreased by 15.29%, 14.64%, 30.22%, 41.03%, and 21.28%. The average sound pressure level at the tympanum decreased by 14.01%, 9.33%, 17.66%, 18.88%, and 25.18%, respectively. In brief, FDS was placed to avoid blood flow impacting vessels and reduce the vibration of vessels in the short term, thereby attenuating the degree of PT. The long-term prognosis was that the SSWD area was blocked after SSD thrombosis. Therefore, FDS might be an effective method for the treatment of PT induced by SSD and SSWD. This study would provide a theoretical basis for the treatment of PT and an exploration of FDS design in the treatment of PT.

Treatment of pulsatile tinnitus caused by anomalies of the sigmoid sinus wall via combined internal and external sigmoid sinus wall reconstruction with 3D temporal bone CT guidance

PURPOSE

The present analysis aims to describe a surgical approach wherein pulsatile tinnitus (PT) arising due to sigmoid sinus wall anomalies (SSWA) can be treated via combination internal and external sigmoid sinus wall reconstruction. We further evaluated the utility of temporal bone 3D-CT imaging during both the pre- and post-operative assessments of all treated patients.

METHODS

Data pertaining to 11 patients that had undergone sigmoid sinus wall reconstruction were retrospectively analyzed. All of these patients underwent preoperative 3D-CT imaging assessment. These patients were additionally subjected to sigmoid sinus wall reconstruction via a combined internal and external layer approach. Postoperatively, all patients underwent a radiological assessment of auricular cartilage and autologous bone powered displacement. Patients were additionally asked about any subjective changes in PT or associated symptoms at follow-up time points.

RESULTS

SSWA in the 3D-CT imaging from these patients were all distinct. In 10/11 patients, PT fully resolved following reconstruction of the sinus wall. The remaining patients exhibited significant improvements in symptoms postoperatively, with PT fully resolving within a 1-month follow-up period. No patients suffered any major complications.

CONCLUSIONS

Temporal bone 3D-CT imaging allow for effective visualization of SSWA, enabling effective pre- and post-operative assessments of treated patients. A combined internal and external layer approach to sigmoid sinus wall reconstruction can be implemented safely and effectively, yielding high rates of satisfactory outcomes and achieving rigid reconstruction of this surface. As such, there is clear value in the consideration of this approach when treating individuals suffering from PT as a result of SSWA.

The styloid process and the formation of sigmoid sinus diverticulum: is there a link?

INTRODUCTION

Sigmoid sinus diverticulum has been considered the most common cause of pulsatile tinnitus; the mechanism underlying sigmoid sinus diverticulum formation is unclear. To the best of our knowledge, no previous studies have assessed whether the formation of sigmoid sinus diverticulum is related to compression of the internal jugular vein by the styloid process.

OBJECTIVE

To discuss the relationship between the styloid process and the formation of sigmoid sinus diverticulum.

METHODS

The medical records of nine patients diagnosed with venous pulsatile tinnitus caused by sigmoid sinus diverticulum were reviewed between April 2009 and May 2019. All patients underwent high-resolution computed tomography of the temporal bones, computed tomography venogram of the head and neck, magnetic resonance venography, and brain magnetic resonance imaging. The length and medial angulation of the styloid process were measured, and compression of the internal jugular vein was recorded.

RESULTS

The study population consisted of nine female right-sided pulsatile tinnitus patients with a mean age of 53.8±4.6 years. The mean lengths of the styloid process were 3.9±0.6cm on the right side and 4.1±0.7cm on the left side. The mean medial angulation of the styloid process was significantly smaller on the right side than the left side (65.3°±1.2° vs. 67.8°±1.7°, p<0.05). In addition, computed tomography venogram of the head and neck demonstrated the left internal jugular vein was compressed by the styloid process in eight of the nine patients.

CONCLUSION

The formation of sigmoid sinus diverticulum with venous pulsatile tinnitus may be related to compression of the contralateral internal jugular vein by the styloid process. However, accumulation of data in additional cases is required to verify this suggestion.