The utility of balloon dilation for piriform aperture stenosis - A first line surgical treatment.

AIM: Describe the long-term outcomes of patients with piriform aperture stenosis managed with balloon dilation. METHODS: Review of current literature. A retrospective case series of 6 patients with piriform aperture stenosis initially managed with balloon dilation at a tertiary paediatric hospital. RESULTS: Six neonates diagnosed with piriform aperture were managed with balloon dilation under general anaesthesia after failing conservative treatment. Average age at first dilation was 28 days old (range 6-54). The piriform aperture was an average width of 5.15 mm, with a 4-6.5 mm range, as measured on axial CT scan. The average width at 25% of the nasal cavity, 50% and 75% was 7.7 mm, 9.3 mm and 9.98 mm respectively. Four neonates required only a single balloon dilation - two of these were stented post-operatively. The remaining two neonates required multiple balloon dilations with eventual drill-out through a sublabial approach. There was a trend of smaller piriform and nasal cavity diameters in those who required multiple procedures. The mean follow-up was 30 months. CONCLUSION: Balloon dilation should be considered for primary operative management in neonates with piriform aperture stenosis who fail medical interventions. Balloon dilation can treat the narrowing at and beyond the piriform aperture. Patients who require more than one dilation are more likely to have a smaller piriform aperture and may need a drill-out procedure. The impact of nasal stents on outcomes is unclear.

Management of paediatric post-tonsillectomy bleeds - does everyone need observation?

AIM: The management of patients who present with a post-tonsillectomy bleed (PTB) who are not actively haemorrhaging is contentious. In our institution, those without an active bleed are admitted for a period of observation, due to the theoretical risk of further bleeding. This paper aims to review PTB admissions to ascertain the risk of rebleeding while under observation and to identify whether there is a low-risk group who can be safely discharged without observation. METHODS: Review of current literature. Retrospective chart review of all patients who presented to Perth Children's Hospital between February 2018 and February 2022 with a PTB. Exclusion criteria included primary PTB, known blood dyscrasias and patients >16 years of age. RESULTS: A total of 826 presentations of secondary PTB (sPTB) were reviewed, with 752 admitted for a period of observation. Twenty-two (2.9%) patients rebled while under observation, with 17 managed operatively. The average age of patients who rebled was 6.2 years and they presented at an average 7.14 post-operative days. The median time to rebleed was 4.4 h. Four patients with no oropharyngeal clot at presentation subsequently re-bled (0.53%) while under observation, with 2 (0.26%) managed surgically. In patients observed with an oropharyngeal clot at presentation 18 (3.1%) rebled, with 15 (2.6%) managed operatively. CONCLUSION: Patients presenting with a sPTB have a low risk of rebleeding while under observation. Patients with a normal oropharyngeal examination at presentation have a very low risk of rebleed and should be considered for early discharge if they meet other low risk criteria. Patients who present with an oropharyngeal clot can be safely observed with a low risk of further bleeding. Patients who rebleed while under observation should have a trial of conservative management if clinically appropriate.

Auditory neuropathy in mice and humans with Friedreich ataxia.

OBJECTIVE: Recent studies have found that human Friedreich ataxia patients have dysfunction of transmission in the auditory neural pathways. Here, we characterize hearing deficits in a mouse model of Friedreich ataxia and compare these to a clinical population. METHODS: Sixteen mice with a C57BL/6 background were evaluated. Eight were YG8Pook/J animals (Friedreich ataxia phenotype) and eight wild-type mice served as controls. Auditory function was assessed between ages 6 and 12 months using otoacoustic emissions and auditory steady-state responses. At study end, motor deficit was assessed using Rotorod testing and inner ear tissue was examined. Thirty-seven individuals with Friedreich ataxia underwent auditory steady-state evoked potential assessment and response amplitudes were compared with functional hearing ability (speech perception-in-noise) and disease status was measured by the Friedreich Ataxia Rating Scale. RESULTS: The YG8Pook/J mice showed anatomic and functional abnormality. While otoacoustic emission responses from the cochlear hair cells were mildly affected, auditory steady-state responses showed exaggerated amplitude reductions as the animals aged with Friedreich ataxia mice showing a 50-60% decrease compared to controls who showed only a 20-25% reduction (F(2,94) = 17.90, p < 0.00). Furthermore, the YG8Pook/J mice had fewer surviving spiral ganglion neurons, indicating greater degeneration of the auditory nerve. Neuronal density was 20-25% lower depending on cochlear region (F(1, 30) = 45.02, p < 0.001). In human participants, auditory steady-state response amplitudes were correlated with both Consonant-Nucleus-Consonant word scores and Friedreich Ataxia Rating Scale score. INTERPRETATION: This study found degenerative changes in auditory structure and function in YG8Pook/J mice, indicating that auditory measures in these animals may provide a model for testing Friedreich ataxia treatments. In addition, auditory steady-state response findings in a clinical population suggested that these scalp-recorded potentials may serve as an objective biomarker for disease progress in affected individuals.

Cannula-based drug delivery to the guinea pig round window causes a lasting hearing loss that may be temporarily mitigated by BDNF.

Sustained local delivery of drugs to the inner ear may be required for future regenerative and protective strategies. The round window is surgically accessible and a promising delivery route. To be viable, a delivery system should not cause hearing loss. This study determined the effect on hearing of placing a drug-delivery microcatheter on to the round window, and delivering either artificial perilymph (AP) or brain-derived neurotrophic factor (BDNF) via this catheter with a mini-osmotic pump. Auditory brainstem responses (ABRs) were monitored for 4 months after surgery, while the AP or BDNF was administered for the first month. The presence of the microcatheter - whether dry or when delivering AP or BDNF for 4 weeks - was associated with an increase in ABR thresholds of up to 15 dB, 16 weeks after implantation. This threshold shift was, in part, delayed by the delivery of BDNF. We conclude that the chronic presence of a microcatheter in the round window niche causes hearing loss, and that this is exacerbated by delivery of AP, and ameliorated temporarily by delivery of BDNF.

The Role of Preoperative Steroids in Atraumatic Cochlear Implantation Surgery.

HYPOTHESIS: Depth of insertion is related to the extent of tissue response and low frequency hearing loss. Intravenous steroids have greatest effect in reducing postimplantation fibrosis and hearing loss in the presence of significant electrode insertion trauma, when compared with saline treatment. BACKGROUND: Experiments exploring the enhancement of cochlear implantation (CI) outcomes with glucocorticosteroids have produced mixed results, possibly due to lack of standardization of the CI model. METHODS: Forty-eight normal-hearing guinea pigs were randomly implanted with a highly flexible electrode to a depth of 1.5, 3.0, or 5.0 mm. For each insertion depth, sub-cohorts received either intravenous saline ("saline") or dexamethasone ("steroid") 60 minutes before implantation. Shifts in electrocochleography thresholds at 2 to 32 kHz were determined before and 4 weeks after implantation. Cochleae were harvested and imaged. RESULTS: Low-frequency hearing loss was greatest with 5.0 mm insertions. Fracture of the osseous spiral lamina and/or fibrotic involvement of the round window membrane exacerbated hearing loss. The extent of intracochlear fibrosis was directly related to the depth of insertion. Steroids reduced the intracochlear tissue response for deepest insertions and in apical regions of the cochlea where basilar membrane contact was prevalent. Steroids preserved no more hearing than saline at all insertion depths. CONCLUSION: Cochlear trauma influenced postimplantation hearing loss and steroid effect on fibrosis. Fibrosis, and to a lesser extent, postimplantation hearing loss increased proportionally to the depth of insertion. Steroids did not influence fibrosis relating to the cochleostomy, but could reduce scarring as the electrode negotiated the hook region or near the electrode tip.

Defining the Hook Region Anatomy of the Guinea Pig Cochlea for Modeling of Inner Ear Surgery.

HYPOTHESIS: The aim of this study was to describe the hook region anatomy of the guinea pig cochlea to identify the optimal surgical approach for cochlear implantation and to determine what anatomical structures are at risk. BACKGROUND: Animal studies investigating hearing loss after cochlear implantation surgery are currently constrained by the lack of a reproducible implantation model. METHODS: Guinea pig cochleae were imaged using thin-sheet laser imaging microscopy. Images were stitched, reconstructed, and segmented for analysis. Insertion vectors were determined by tracing their paths to the outer wall and converting to Cartesian coordinates. Spherical surface and multiplane views were generated to analyze outer wall and radial forces of the insertion vector. RESULTS: Thin-sheet laser imaging microscopy enabled quantitative, whole specimen analysis of the soft and bony tissue relationships of the complex cochlear hook region in any desired plane without loss of image quality. Round window or cochleostomy approaches in the anteroinferior plane avoided direct damage to cochlear structures. Cochleostomy approach had large interindividual variability of angular depth and outer wall forces but predictable radial force. CONCLUSION: The guinea pig hook region and lower basal turn have similar structural relationships to humans. Careful cochleostomy placement is essentially for minimizing cochlear trauma and for ensuring a straight insertion vector that successfully advances around the outer wall. Experiments with guinea pigs that control for the surgical approach are likely to provide useful insights into the aetiology and the development of therapies directed at postimplantation hearing loss.

Simultaneous tonsillectomy and nasal surgery in adult obstructive sleep apnea: a pilot study.

OBJECTIVE: Although adenotonsillectomy is the accepted treatment for obstructive sleep apnea (OSA) in the pediatric population, tonsillectomy has not been widely adopted in adults, and its success in this group has not been well reported. Despite the lack of current evidence, there may be an important role for tonsillectomy in selected adult cases, and further study is required. This is a pilot study from a larger group of subjects currently enrolled and awaiting surgery and repeat polysomnography. STUDY DESIGN: Retrospective series with chart review. SETTING: Tertiary referral teaching hospitals. SUBJECTS AND METHODS: Thirteen consecutive eligible subjects with tonsillar hypertrophy and OSA were identified after treatment. These patients had undergone pre- and postoperative polysomnography for assessment of the severity of sleep-disordered breathing. Post hoc analysis of key parameters was performed by Wilcoxon signed rank and paired t tests. Tonsillectomy was performed on all subjects, using the diathermy dissection technique. Nasal surgery was performed simultaneously in 11 subjects for symptomatic nasal blockage unresponsive to medical treatment. RESULTS: There was a statistically significant improvement in the severity of OSA after surgery. The total Respiratory Disturbance Index (RDI) was significantly decreased from median values of 31.7 to 5.5 (P = .0002). The RDI in rapid eye movement and non-rapid eye movement sleep and the arousal index were also significantly decreased. CONCLUSION: In selected adult subjects, tonsillectomy with intercurrent nasal surgery should be considered an effective treatment for OSA and may reduce the requirement for continuous positive airway pressure, oral appliances, or further therapeutic intervention.