Role of HRCT imaging in predicting the visibility of Round window (RW) on patients underwent cochlear implant surgery

Objective evaluation, using computed tomography, of round window access for cochlear implantation

OBJECTIVE

The aim of this study was to determine optimal radiological parameters for assessment of the round window approach in cochlear implantation surgery.

MATERIALS AND METHODS

Patients undergoing cochlear implantation at the Department of Otolaryngology in Szczecin, between 2015 and 2022 inclusive, were eligible for the study. Radiological assessments were performed according to eight parameters (seven proposed in the literature) and visibility clinical assessments were made intra-operatively on a scale of 1 to 5 (1 - not visible, 5 - fully visible). Visibility assessments of the round window niche (RWN) and round window membrane (RWM) allowed the difference (RWN minus RWM) to be used as a clinical assessment of the size of the overhang over the round window.

RESULTS

Computed tomography images of 57 ears from 52 patients were analyzed in terms of round window access. The study group included 26 females and 26 males, ranging in age from 1 year to 80 years, with a median age of 41 years. In clinical assessment, round window visibility was rated as 5, after removal of the bone overhang, in 69% of patients. Cochlear access through the round window was achieved in 39 (68%) cases, extended access through the round window in 13 (23%) cases and cochleostomy was performed in 5 (9%) cases. Statistically significant ordinal correlations with round-window access were found using one parameter from the literature (Chen_Angle) and from our proposal (RWM_prediction). From parameters describing the bone overhang of the round window, positive correlations (using Kendall rank tests) were found using parameters from the literature (Sarafraz_OH and Mehanna_OH).

CONCLUSIONS

Radiological measurements describing access to the round window which determine the angle based on the anatomy of the posterior wall of the auditory canal and the position of the facial nerve were found to be of the highest value.

CLINICAL RELEVANCE STATEMENT

In the future, the use of algorithms for computed tomography evaluation and robot-assisted surgery will require parameters for assessing round window access, for surgery planning and choice of electrode. The parameters proposed by various authors are summarized, allowing researchers to assess their usefulness in further clinical practice.

Radioclinical Assessment of Posterior Tympanotomy Difficulties during Ordinary Cochlear Implantation: A Prospective Case-Series Study

OBJECTIVES

This study proposes a preoperative radiologic scoring system for predicting posterior tympanotomy (PT) and mastoidectomy-associated difficulties during cochlear implantation (CI).

STUDY DESIGN

It was a prospective case-series study.

SETTINGS

The included CI surgeries were performed at tertiary referral institutions from October 2022 to April 2023.

SUBJECTS

We included 73 CI candidates performed via the PT approach.

INTERVENTION

The proposed radiologic score, composed of 13 items, was fulfilled and evaluated before each CI surgery.

MAIN OUTCOME MEASURE

We correlated this score with the intraoperative difficulty and surgical duration.

RESULTS

The operation was straightforward in 42 patients with a score of 3.87 ± 1.72 and challenging in 31 patients with a score of 10.66 ± 1.73. The radiologic score was strongly correlated with the surgical difficulty and duration (p < 0.0001).

CONCLUSIONS

Our proposed radiologic score was a valid, reliable, and precise tool to predict intraoperative difficulty during cochlear implantation. Chorda-facial angle was the strongest predictor, significantly affecting the difficulty, surgical duration, and preoperative radiologic score. A score equal to or more than 7.5 was expected to be associated with surgical difficulty.

Anatomical Variations, Surgical Difficulties, and Complications Associated with Cochlear Implantation in Different Age Groups of the Pediatric Population of Nepal: A Tertiary Level Hospital-Based Study

Pediatric cases account for the major proportion of the population for whom cochlear implantation is indicated. This study aims to review the anatomical variations, surgical difficulties, and complications associated with cochlear implantation surgery in different age groups of the pediatric population of Nepal.This study was conducted at Tribhuvan University Teaching Hospital, Nepal. A prospectively set data of cases who underwent cochlear implantation between January 2015 and March 2020 were analyzed for details of surgical procedure, surgical difficulties, and intraoperative and postoperative complications. The anatomical variations encountered during surgery were classified as: developmental anomalies, round window niche variations and acquired abnormalities resulting from inflammation. Intraoperative surgical difficulties were defined based on the operating surgeon's perspective. Complications following cochlear implantation were classified as surgical and nonsurgical or device-related. We used SPSS version 25 for the analysis of our data. Chi-square test and Fisher's exact test were used to analyze the statistical association.The most commonly encountered difficulty was the requirement of an extended posterior tympanotomy approach due to poor visualization of round window niche. There was a statistically significant association of difficult insertion of electrodes with round window niche visibility. The common complications encountered were intraoperative facial nerve exposure, bleeding, electrode-related problems, cerebrospinal fluid gusher, and device failure.Cochlear implantation with an experienced surgeon in pediatric population is a relatively safe procedure. There is no association of the difficulties and complications related to surgery with the different age groups.

The Impact of the Location of Chorda Tymapni Nerve Origin on the Round Window Accessibility During Pediatric Cochlear Implantation: A Radioclinical Assessment

OBJECTIVES

This study assessed the impact of the location of the chorda tympani nerve (CTN) origin on the round window (RW) accessibility during pediatric cochlear implantation (CI). We also tried to validate the radiologic method to measure the length between the origin of the CTN from the facial nerve to the stylomastoid foramen (CF-SM).

STUDY DESIGN

It was a prospective observational case-series study.

SETTINGS

The included CI surgeries were performed at tertiary referral institutions from November 2018 to August 2021.

SUBJECTS

We included 146 pediatric patients who were candidates for CI.

INTERVENTION

We measured the CF-SM length in the parasagittal cut of the preoperative high-resolution computed tomography. We also classified the intraoperative RW according to the accessibility through the ordinary posterior tympanotomy approach into accessible or inaccessible.

MAIN OUTCOME MEASURE

We correlated the preoperative radiologic CF-SM length with the intraoperative RW accessibility.

RESULTS

The radiologic CF-SM length ranged from 2.9 to 7.4 mm with a mean of 4.9 ± 1.03 mm. The RW was accessible in 107 patients and inaccessible in 39 patients. Spearman's correlation coefficient revealed a significant relationship between the location of CTN origin and the RW accessibility as the p value was less than 0.0001.

CONCLUSIONS

We found a precise method to measure the CF-SM length in the parasagittal cut of the high-resolution computed tomography. We also found a significant impact of the location of the CTN origin on intraoperative RW accessibility. The radiologic CF-SM length of more than 5.4 mm had a powerful prediction capability of the RW inaccessibility.

Radiological Analysis of the Facial Recess: Impact on Posterior Tympanotomy Difficulty During Pediatric Cochlear Implantation

OBJECTIVES

We analyzed several radiological features of the facial recess to correlate them with the intraoperative findings to highlight the most reliable predictors of posterior tympanotomy difficulty.

STUDY DESIGN

Retrospective observational cohort study.

SETTING

Multicenter study at tertiary referral institutions.

METHODS

We included 184 pediatric patients who underwent cochlear implantation through the posterior tympanotomy approach. The correlation was attempted between 8 radiological features in the preoperative high-resolution computed tomography scan and intraoperative surgical difficulty.

RESULTS

Posterior tympanotomy was straightforward in 136 (73.9%) patients. In contrast, it was challenging in 48 (26.1%) patients. The facial recess was aerated in 74.5% of patients. The mean (SD) posterior tympanotomy depth was 3.98 (0.867) mm. The mean (SD) chorda-facial angle was 27.67° (3.406°). The mean (SD) chorda-facial to stylomastoid length was 3.898 (0.6304) mm. The mean (SD) facial nerve second genu angle was 94.54° (6.631)°. Deep-unaerated facial recess wall was associated with the most difficulty. There was a statistically significant difference in the unchallenging and challenging posterior tympanotomy groups regarding the surgical duration (P < .0001).

CONCLUSIONS

According to this analytic study, the chorda-facial angle, the facial recess aeration, and the chorda-facial to stylomastoid length were respectively the strongest preoperative radiological predictors of the surgical difficulty of posterior tympanotomy during cochlear implantation. Chorda-facial angle <25.5° was associated with difficult posterior tympanotomy. The oblique parasagittal cut was essential for the radiological analysis of the facial recess.

Cellular and Molecular Targeted Drug Delivery in Central Nervous System Cancers: Advances in Targeting Strategies

Central nervous system (CNS) cancers are among the most common and treatment-resistant diseases. The main reason for the low treatment efficiency of the disorders is the barriers against targeted delivery of anticancer agents to the site of interest, including the blood-brain barrier (BBB) and blood-brain tumor barrier (BBTB). BBB is a strong biological barrier separating circulating blood from brain extracellular fluid that selectively and actively prevents cytotoxic agents and majority of anticancer drugs from entering the brain. BBB and BBTB are the major impediments against targeted drug delivery into CNS tumors. Nanotechnology and its allied modalities offer interesting and effective delivery strategies to transport drugs across BBB to reach brain tissue. Integrating anticancer drugs into different nanocarriers improves the delivery performance of the resultant compounds across BBB. Surface engineering of nanovehicles using specific ligands, antibodies and proteins enhances the BBB crossing efficacy as well as selective and specific targeting to the target cancerous tissues in CNS tumors. Multifunctional nanoparticles (NPs) have brought revolutionary advances in targeted drug delivery to brain tumors. This study reviews the main anatomical, physiological and biological features of BBB and BBTB in drug delivery and the recent advances in targeting strategies in NPs-based drug delivery for CNS tumors. Moreover, we discuss advances in using specific ligands, antibodies, and surface proteins for designing and engineering of nanocarriers for targeted delivery of anticancer drugs to CNS tumors. Finally, the current clinical applications and the perspectives in the targeted delivery of therapeutic molecules and genes to CNS tumors are discussed.

Combined preoperative HRCT parameters for prediction of round window visibility in pediatric cochlear implant patient

OBJECTIVE

To evaluate the add value of combined analysis of high resolution computed tomography (HRCT) temporal bone parameters in accurate prediction of round window (RW) visibility through posterior tympanotomy.

PATIENTS AND METHODS

a retrospective observational study was held in a tertiary center, conducted on 45 cochlear implant pediatric candidates between January 2017 and September 2019. Candidates were referred for CT temporal bone. They were classified into fully visible RW cases and partially or non-visible RW cases. Radiological measurements were compared between the two groups for prediction of RW visibility separate and in combination.

RESULTS

45 patients were included in the study (26 males (57.8%) and 19 females (42.2%)). Their median age was 4 years (2-12 years). There were 38 (84.4%) fully visible and 7 (15.6%) partially or non-visible RW cases. Kashio posterior line (n:32/3), fascial recess width (FRW) (mean: 4.9 (3.5-7.5)/4.2 (4-4.7) mm) and round window location (RWL) (3 (1-4)/2.8 (1-3)mm) measurements significantly differentiated between the two groups; (P value 0.034, 0.012 & 0.025 respectively). Posterior kashio line and cut off values of ≥4.75 mm of FRW & 2.95 mm of RWL were showed sensitivity 84.2%, 63.2% & 65.8%, and accuracy 80%, 68.9% &68.9% in prediction of RW visibility respectively. Combination of Kashio prediction line with cut off value ≥ 7.45 mm (sum of FRW & RWL) showed P value 0.003 with further improve in the sensitivity and overall accuracy in prediction of RW visibility from 84.2% to 80% up to 91.4% and 88.6% respectively.

CONCLUSION

combined parameters using Kashio line with FRW and RWL increases sensitivity and overall accuracy in prediction of RW visibility rather than single parameter.

Nanomedicine and Early Cancer Diagnosis: Molecular Imaging using Fluorescence Nanoparticles

Incorporating nanotechnology into fluorescent imaging and magnetic resonance imaging (MRI) has shown promising potential for accurate diagnosis of cancer at an earlier stage than the conventional imaging modalities. Molecular imaging (MI) aims to quantitatively characterize, visualize, and measure the biological processes or living cells at molecular and genetic levels. MI modalities have been exploited in different applications including noninvasive determination and visualization of diseased tissues, cell trafficking visualization, early detection, treatment response monitoring, and in vivo visualization of living cells. High-affinity molecular probe and imaging modality to detect the probe are the two main requirements of MI. Recent advances in nanotechnology and allied modalities have facilitated the use of nanoparticles (NPs) as MI probes. Within the extensive group of NPs, fluorescent NPs play a prominent role in optical molecular imaging. The fluorescent NPs used in molecular and cellular imaging can be categorized into three main groups including quantum dots (QDs), upconversion, and dyedoped NPs. Fluorescent NPs have great potential in targeted theranostics including cancer imaging, immunoassay- based cells, proteins and bacteria detections, imaging-guided surgery, and therapy. Fluorescent NPs have shown promising potentials for drug and gene delivery, detection of the chromosomal abnormalities, labeling of DNA, and visualizing DNA replication dynamics. Multifunctional NPs have been successfully used in a single theranostic modality integrating diagnosis and therapy. The unique characteristics of multifunctional NPs make them potential theranostic agents that can be utilized concurrently for diagnosis and therapy. This review provides the state of the art of the applications of nanotechnologies in early cancer diagnosis focusing on fluorescent NPs, their synthesis methods, and perspectives in clinical theranostics.