Study Objectives: To determine whether therapeutic positive airway pressure (PAP) level predicts response to hypoglossal nerve stimulation (HGNS) for obstructive sleep apnea using the coprimary outcomes of apnea-hypopnea index (AHI) and 4% oxygen desaturation index. Methods: Combined cohort study from two US sleep otolaryngology training programs. Subjects were adults with AHI > 15 events/h who underwent HGNS. Eligible subjects had diagnostic preoperative sleep studies, full-night efficacy postoperative studies and therapeutic PAP levels available for analysis. Low and high PAP groups were compared using the t test for continuous variables and chi-square test for categorical variables. Results: Fifty-six patients met all inclusion criteria. On average, patients were male, Caucasian, middle-aged, and overweight. Thirteen patients were in the low PAP group (< 8 cm H 2 O) and 43 patients in the high PAP group (≥ 8 cm H 2 O). Although both groups experienced improvement of polysomnographic measures with HGNS, the low PAP group achieved a significantly larger mean AHI reduction (36.7 ± 22.7 versus 18.4 ± 23.4, P = .02). Additionally, the low PAP group had a greater response rate (defined as AHI < 20 events/h and > 50% reduction of AHI) than the high PAP group (92% versus 44%, P < .01).Conclusions: Therapeutic PAP level may aid in the discernment of candidacy for HGNS, with a strong positive predictive value for PAP levels < 8 cm H 2 O. A larger prospective study is needed to confirm these findings.
Objectives/hypothesis
Composite vocal fold (VF) biomechanical data are lacking for augmentation after recurrent laryngeal nerve (RLN) injury. We hypothesize resulting atrophy decreases VF stiffness and augmentation restores native VF biomechanics.
Methods
Sixteen Yorkshire Crossbreed swine underwent left RLN transection and were observed or underwent carboxymethylcellulose (CMC) or calcium hydroxyapatite (CaHa) augmentation at 2 weeks. Biomechanical measurements (structural stiffness, displacement, and maximum load) were measured at 4 or 12 weeks. Thyroarytenoid (TA) muscle cross‐sectional area was quantified and compared with two‐way ANOVA with Tukey's post hoc test.
Results
After 4 weeks, right greater than left structural stiffness (mean ± SE) was observed (49.6 ± 0.003 vs. 28.4 ± 0.002 mN/mm), left greater than right displacement at 6.3 mN (0.54 ± 0.01 vs. 0.46 ± 0.01 mm, p < .01) was identified, and right greater than left maximum load (72.3 ± 0.005 vs. 40.8 ± 0.003 mN) was recorded. TA muscle atrophy in the injured group without augmentations was significant compared to the noninjured side, and muscle atrophy was seen at overall muscle area and individual muscle bundles. CMC augmentation appears to maintain TA muscle structure in the first 4 weeks with atrophy present at 12 weeks.
Conclusions
VF biomechanical properties match TA muscle atrophy in this model, and both CMC and CaHa injection demonstrated improved biomechanical properties and slower TA atrophy compared to the uninjured side. Taken together, these data provide a quantifiable biomechanical basis for early injection laryngoplasty to improve dysphonia and potentially improve healing in reversible unilateral vocal fold atrophy.
Level of evidence
N/A
The changes in the resistance of the perfused ventral rat-tail artery resulting from exposure of the tissue to ouabain-containing and/or K+-free physiological salt solution were studied. In each case, there was an increase in the vascular resistance which was not sustained. The response of the arterial wall to the above stimuli was abolished in the absence of external Ca2+. In contrast to the delayed response of the wall to either ouabain-containing or K+-free solution, an almost instantaneous rise in the resistance was observed if the two stimuli were combined, though the rate of loss of the tissue K+ was not accelerated significantly under these experimental conditions. The tension developed in K+-free solution was relieved almost instantaneously upon readmittance of external potassium.
Giant cell arteritis (GCA) is an important condition to suspect and treat early, as failure to do so can result in anterior ischaemic optic neuropathy and subsequent permanent visual loss. A 71-year-old woman presented to her local emergency department with a 1-week history of constant, moderatesevere global headache associated with intermittent periorbital pain. Two weeks later she developed sudden horizontal diplopia. Examination demonstrated right oculomotor nerve palsy. Her erythrocyte sedimentation rate (ESR) was 9 mm/hr. Repeat blood tests 1 month later showed an ESR of 67 mm/hr. Temporal artery biopsy was positive. A review from a cohort of 764 patients with suspected GCA who underwent biopsy found the sensitivity of an elevated ESR and C-reactive protein was 84% and 86%, respectively, but the specifi city was only 30%. Therefore, infl ammatory markers should only act as a guide, and caution should be taken in their interpretation especially with respect to the time of sampling in the disease evolution. Isolated oculomotor nerve palsy in association with GCA is rare. The fi rst case series was described by Miller Fisher in 1959 who observed two patients presenting with diplopia, ptosis and ocular palsies. In anyone over the age of 50 who develops a new, refractory headache and cranial neuropathy, GCA should be the fi rst consideration.
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