Faculty Bibliography

OBJECTIVES: We report the frequency and success rates of adjunctive airway procedures after pediatric single-stage laryngotracheoplasty (LTP) and review different adjunctive techniques in a prospectively enrolled and retrospectively reviewed case series. METHODS: Of 31 LTP procedures performed from 2008 to 2011 at an academic tertiary care children's hospital, 10 were single-stage LTP procedures. These 10 cases were analyzed to determine the number and type, if any, of adjunctive procedures required after LTP, as well as the subglottic response and decannulation rates. RESULTS: Of the 10 patients with single-stage LTP procedures, 6 patients required a total of 16 postoperative adjunctive airway procedures. The adjunctive procedures included granulation tissue removal with forceps or a carbon dioxide laser, stent placement, mitomycin C application, and triamcinolone acetonide injection. One patient also required tracheotomy placement and, eventually, cricotracheal resection. All 6 patients had significant improvement of subglottic and/ or tracheal stenosis on their most recent endoscopic examination. With a minimum follow-up of 12 months, all 6 patients were decannulated. CONCLUSIONS: In this series, more than half of our pediatric patients who underwent single-stage LTP required 1 or more postoperative adjunctive procedures, and all had successful outcomes.

OBJECTIVES/HYPOTHESIS/OBJECTIVE:Using human cadavers, we investigated the feasibility of using a new robotic platform, the Medrobotics Flex System, for laryngeal access and flexible tool delivery to facilitate the performance of pharyngolaryngeal procedures without laryngeal suspension. Our initial trials specifically assess the utility of this experimental robotic system for epiglottectomy and base of tongue resection. STUDY DESIGN/METHODS:Feasibility; Level of evidence: NA. METHODS:Using standard mouth retractors, the Flex™robot was driven via the physician controller to the supraglottic region. Non-crossing, flexible endoscopic tools were inserted through the robot's external tool channels to retract, cauterize, and remove tissue in each procedure type. Mock surgical procedures were performed on the laryngopharyngeal complex including epiglottectomy, base of tongue resection, and vocal cord excision. Time-to-tissue exposure was noted for each procedure. Each epiglottectomy was timed to determine operation duration. RESULTS:Epiglottectomy, base of tongue resection, and vocal cord excision were successfully performed without suspension laryngoscopy. Individual surgeons improved the procedure time significantly (P = 0.03) between first and second attempts. Epiglottectomies were performed in an average time of 42 minutes (N = 5, σ = 28 minutes). CONCLUSIONS:The Medrobotics Flex System demonstrates great potential as a surgical tool in head and neck oncology. Compared to other surgical robots, the Flex System offers facilitated access, vision, and triangulation of flexible tools for procedures in the endolarynx. LEVEL OF EVIDENCE/METHODS:N/A.

The term "formant tuning" is generally used for the case that one of the lowest formant frequencies coincides with the frequency of a source spectrum partial. Some authors claim that such coincidence is favorable and belongs to the goals of classical opera voice training, whereas other authors have found evidence for advising against it. This investigation analyzes the relationships between formant frequencies and partials in professional singers, who sang scales on the vowels /a/, /u/, /i/, and /ae/ in a pitch range including the passaggio, that is, the fundamental frequency range of approximately 300-400Hz, applying either of the two singing strategies that are typically used (1) in classical and (2) in nonclassical singing, respectively. Formant frequencies of each note in the scales were measured by inverse-filtering the acoustic signal. In the classical style, the first formant tended to be lower than in the nonclassical style. Neither the first nor the second formant tended to change systematically between scale tones, such that on some scale tones either or both formants was just below, just above, or right on a spectrum partial. In many cases, singers produced similar spectrum characteristics of the top tones of the scales with different first and second formant frequencies. Regardless of whether the first formant was slightly lower, slightly higher, or right on a partial, the properties of the voice source did not seem to be affected.

IMPORTANCE: The extended columellar strut-tip graft was designed to improve nasal tip projection and tip definition in patients undergoing rhinoplasty. OBJECTIVE: To determine whether the extended columellar tip graft leads to a true and measurable increase in nasal tip projection or simply gives the illusion of an increase in projection. DESIGN: Retrospective case review. The mean time of follow-up photographs was 32 months after surgery (range, 8 months to 10 years). PARTICIPANTS: The study population comprised 15 patients who underwent primary or revision rhinoplasty during the last 10 years. INTERVENTION: Primary or revision rhinoplasty. MAIN OUTCOME MEASURE: The outcome measure was the long-term gain in nasal tip projection. Preoperative and postoperative images were cropped and sized equally for accurate comparison. All measurements were made from the alar-facial crease to the tip defining point. RESULTS: In all 15 patients, an increase in tip projection was obtained. The mean increase in projection was 19% compared with the preoperative projection. After applying a paired t test for analysis, there was a statistically significant increase in nasal projection (P < .05). CONCLUSIONS AND RELEVANCE: The extended columellar strut-tip graft effectively corrected poor nasal tip projection. The effect is maintained years later. The extended columellar strut-tip graft is an excellent choice in endonasal rhinoplasty to improve poor tip projection and definition. LEVEL OF EVIDENCE: 4.

Acoustic models have been used in numerous studies over the past thirty years to simulate the percepts elicited by auditory neural prostheses. In these acoustic models, incoming signals are processed the same way as in a cochlear implant speech processor. The percepts that would be caused by electrical stimulation in a real cochlear implant are simulated by modulating the amplitude of either noise bands or sinusoids. Despite their practical usefulness these acoustic models have never been convincingly validated. This study presents a tool to conduct such validation using subjects who have a cochlear implant in one ear and have near perfect hearing in the other ear, allowing for the first time a direct perceptual comparison of the output of acoustic models to the stimulation provided by a cochlear implant.

Cochlear implant (CI) users typically have excellent speech recognition in quiet but struggle with understanding speech in noise. It is thought that broad current spread from stimulating electrodes causes adjacent electrodes to activate overlapping populations of neurons which results in interactions across adjacent channels. Current focusing has been studied as a way to reduce spread of excitation, and therefore, reduce channel interactions. In particular, partial tripolar stimulation has been shown to reduce spread of excitation relative to monopolar stimulation. However, the crucial question is whether this benefit translates to improvements in speech perception. In this study, we compared speech perception in noise with experimental monopolar and partial tripolar speech processing strategies. The two strategies were matched in terms of number of active electrodes, microphone, filterbanks, stimulation rate and loudness (although both strategies used a lower stimulation rate than typical clinical strategies). The results of this study showed a significant improvement in speech perception in noise with partial tripolar stimulation. All subjects benefited from the current focused speech processing strategy. There was a mean improvement in speech recognition threshold of 2.7 dB in a digits in noise task and a mean improvement of 3 dB in a sentences in noise task with partial tripolar stimulation relative to monopolar stimulation. Although the experimental monopolar strategy was worse than the clinical, presumably due to different microphones, frequency allocations and stimulation rates, the experimental partial-tripolar strategy, which had the same changes, showed no acute deficit relative to the clinical.

Background Whole brain radiation therapy (WBRT) reduces local recurrence in patients after surgical resection of brain metastases without improving overall survival. Involved field radiation therapy (IFRT) has been used at our center to avoid delayed neurotoxicity associated with WBRT in well-selected patients with surgically resected single brain metastases. The purpose of this study was to evaluate the long-term outcomes of these patients. Methods Thirty-three consecutive patients with single brain metastases from a known primary tumor were treated with gross total resection followed by IFRT between 2006 and 2011. The postoperative surgical bed was treated to 40.05 Gy in 15 fractions of 2.67 Gy with conformal radiation therapy. Patients received serial MRIs and neurological exams in follow-up. Surgery, WBRT, or stereotactic radiosurgery was performed as salvage treatment when necessary. Results The median follow-up was 16 months (range: 2-65 months). Local control, distant brain recurrence-free survival, and overall survival at 12 and 24 months were 90.3% and 85.8%, 60.7% and 51.4%, and 65.6% and 61.5%, respectively. Overall, 5 (15%) patients developed recurrence at the resection cavity, and 13 (39%) patients experienced recurrence at a new intracranial site. Two patients received WBRT, 8 stereotactic radiosurgery, 2 surgery, and 2 both chemotherapy and IFRT as salvage. Four patients died from CNS disease progression. Conclusion For patients with newly diagnosed single brain metastases treated with surgical resection, postoperative IFRT to the resection cavity achieves reasonable rates of local control and is an excellent alternative to WBRT.

Rationale: Compartmentation of ion channels on the cardiomyocyte surface is important for electric propagation and electromechanical coupling. The specialized T-tubule and costameric structures facilitate spatial coupling of various ion channels and receptors. Existing methods such as immunofluorescence and patch clamp techniques are limited in their ability to localize functional ion channels. As such, a correlation between channel protein location and channel function remains incomplete. Objective: To validate a method that permits routine imaging of the topography of a live cardiomyocyte and study clustering of functional ion channels from a specific microdomain. Methods and Results: We used scanning ion conductance microscopy and conventional cell-attached patch clamp with a software modification that allows controlled increase of pipette tip diameter. The sharp nanopipette used for topography scan was modified into a larger patch pipette that could be positioned with nanoscale precision to a specific site of interest (crest, groove, or T-tubules of cardiomyocytes) and sealed to the membrane for cell-attached recording of ion channels. Using this method, we significantly increased the probability of detecting activity of L-type calcium channels in the T-tubules of ventricular cardiomyocytes. We also demonstrated that active sodium channels do not distribute homogenously on the sarcolemma instead, they segregate into clusters of various densities, most crowded in the crest region, that are surrounded by areas virtually free of functional sodium channels. Conclusions: Our new method substantially increases the throughput of recording location-specific functional ion channels on the cardiomyocyte sarcolemma, thereby allowing characterization of ion channels in relation to the microdomain where they reside.

The mechanisms by which natural rewards such as sugar affect synaptic transmission and behavior are largely unexplored. Here, we investigate regulation of nucleus accumbens synapses by sucrose intake. Previous studies have shown that AMPA receptor (AMPAR) trafficking is a major mechanism for regulating synaptic strength, and that in vitro, trafficking of AMPARs containing the GluA1 subunit takes place by a two-step mechanism involving extrasynaptic and then synaptic receptor transport. We report that in rat, repeated daily ingestion of a 25% sucrose solution transiently elevated spontaneous locomotion and potentiated accumbens core synapses through incorporation of Ca(2+)-permeable AMPA receptors (CPARs), which are GluA1-containing, GluA2-lacking AMPARs. Electrophysiological, biochemical, and quantitative electron microscopy studies revealed that sucrose training (7 d) induced a stable (>24 h) intraspinous GluA1 population, and that in these rats a single sucrose stimulus rapidly (5 min) but transiently (<24 h) elevated GluA1 at extrasynaptic sites. CPARs and dopamine D1 receptors were required in vivo for elevated locomotion after sucrose ingestion. Significantly, a 7 d protocol of daily ingestion of a 3% solution of saccharin, a noncaloric sweetener, induced synaptic GluA1 similarly to 25% sucrose ingestion. These findings identify multistep GluA1 trafficking, previously described in vitro, as a mechanism for acute regulation of synaptic transmission in vivo by a natural orosensory reward. Trafficking is stimulated by a chemosensory pathway that is not dependent on the caloric value of sucrose.