Development of the rat larynx: a histological study

OBJECTIVES/HYPOTHESIS

To evaluate and describe the cartilaginous and muscular development of the rat larynx.

STUDY DESIGN

Histologic evaluation.

METHODS

The larynges of Sprague Dawley rats of embryonic day (E) 13, 15, 17, 19, 21, postnatal day 0, 14, and adult of 250 gm were collected. Four larynges of each age were harvested, cut into 15-μm serial sections, stained with hematoxylin and eosin, and evaluated under light microscopy. Representative digital images were recorded and evaluated at the preglottic (supraglottic in humans), glottic, and postglottic (subglottic in humans) levels.

RESULTS

Brachial arches were observed at E13. At E17, immature structures of the larynx, including skeletal muscle, cartilage, and the lumen were identifiable. Chondrification and muscle formation were clearly seen by E19. The muscular and cartilagenous components of the larynx were well established by E21. During the span between birth and adult maturation, the size of the larynx increased from a height of 1.10 mm to 2.90 mm, and from a width of 1.80 mm to 5.40 mm, and from a length of 1.38 mm to 4.77 mm in the stained section. Although developed at E21, the laryngeal structures continued to grow by approximately 30%.

CONCLUSION

Rat laryngeal development parallels that in mice and humans. In the rat, at E17 immature structures of the larynx are identifiable, they are well developed at birth and grow by approximately 30% into adulthood. Understanding the chronology and morphology of the embryogenesis of the rat laryngeal musculature is essential and will allow for further evaluation of the embryologic innervation of these muscles.

Photoangiolytic laser treatment of recurrent respiratory papillomatosis: a scaled assessment

OBJECTIVES

To investigate the effectiveness of unsedated office-based photoangiolytic laser surgery (UOLS) for treating recurrent respiratory papillomatosis (RRP) using the Derkay severity scale, Voice Handicap Index-10 (VHI-10), and Grade, Roughness, Breathiness, Asthenia, Strain (GRBAS) scale. Although previous studies examined the effect of UOLS on voice quality, few studies evaluated the effect on disease regression or used accepted and validated scales as outcome measures.

STUDY DESIGN

Retrospective case series.

METHODS

Charts were reviewed for patients who underwent UOLS for RRP (2007-2010). Twenty-one patients met the inclusion criteria. Nineteen patients underwent treatment with a 532-nm potassium titanyl phosphate laser and two with a 585-nm pulsed dye laser. The Derkay, VHI-10, and GRBAS scores of posttreatment findings were compared with those of the pretreatment findings.

RESULTS

Twenty-one patients underwent 81 office procedures. Mean follow-up was 18 months. From baseline to latest follow-up, there was significant improvement in the mean Derkay score from 6.1 to 3.0 (P=0.001), VHI-10 score from 24.5 to 15.9 (P=0.04), and GRBAS score from 8.6 to 4.9 (P=0.004).

CONCLUSIONS

UOLS results in patient benefit from disease regression, reduced voice handicap, and improved voice quality without the risks associated with direct laryngoscopy and general anesthesia. UOLS is an effective, safe, nonexperimental treatment modality for RRP that has shifted the therapeutic paradigm while decreasing patient morbidity.

Variability of postoperative esophagrams after endoscopic cricopharyngeal myotomy: technique dependence

OBJECTIVES

We illustrate the dependence of postoperative day (POD) 1 esophagram findings on the closure technique used after endoscopic cricopharyngeal myotomy (ECPM).

METHODS

We performed a retrospective chart review of POD 1 fluoroscopic examinations of the cervical esophagus utilizing contrast dye after ECPM to assess radiologic findings associated with three different techniques of addressing the exposed buccopharyngeal fascia (BPF).

RESULTS

Each technique resulted in specific and different findings on the POD 1 esophagram. When the BPF was untreated, the esophagram demonstrated a pseudodiverticulum with free flow of contrast dye. When a fibrin glue seal was used, the esophagram demonstrated a curvilinear focus of contrast dye projected over the retropharyngeal soft tissue persisting after the swallow, similar to a leak. When fibrin glue application was combined with single-suture reapproximation of the mucosal incision, the pattern was similar to esophagrams performed 6 weeks after myotomy.

CONCLUSIONS

Different techniques used to address the exposed BPF following ECPM result in specific findings on the POD 1 esophagram. Recognition of these imaging differences and open communication with the fluoroscopist will avoid a misdiagnosis of a pharyngeal leak, which might cause an unnecessary delay of oral feeding and hospital discharge.

Management of Dysphonic Patients by Otolaryngologists

Objective

To investigate common treatment approaches of general otolaryngologists for adult dysphonic patients without obvious laryngeal anatomic abnormalities.

Study Design

Cross-sectional survey.

Setting

General otolaryngology community.

Subjects and Methods

One thousand randomly chosen American Academy of Otolaryngology—Head and Neck Surgery general otolaryngologists were mailed a survey.

Results

The response rate was 27.8%. Mean years in practice was 19.5. The most common treatments were proton pump inhibitor (PPI), referral to speech pathology, and stroboscopy. Muscle tension dysphonia, vocal fold nodules, and dysphonia of uncertain etiology were the most common reasons for voice therapy referral. Various forms of supraglottic compression and tender extralaryngeal muscles were identified as findings of muscle tension dysphonia. Response to once-daily PPI, laryngeal signs, and throat symptoms were the most common determinants for laryngopharyngeal reflux. When patients failed initial treatment, 58.2% refer for voice therapy, 46.9% obtain stroboscopy, and 33.3% extend or increase duration of PPI treatment.

Conclusions

Varied treatment approaches to adult dysphonic patients were identified. How practice patterns vary from best practice guidelines, affect patient outcome, and influence health care costs needs examination.

Quantity and three-dimensional position of the recurrent and superior laryngeal nerve lower motor neurons in a rat model

OBJECTIVES

We sought to elucidate the 3-dimensional position and quantify the lower motor neurons (LMNs) of the recurrent laryngeal nerve (RLN) and the superior laryngeal nerve (SLN) in a rat model. Quantification and mapping of these neurons will enhance the usefulness of the rat model in the study of reinnervation following trauma to these nerves.

METHODS

Female Sprague-Dawley rats underwent microsurgical transection of the RLN, the SLN, or both the RLN and SLN or sham surgery. After transection, either Fluoro-Ruby (FR) or Fluoro-Gold (FG) was applied to the proximal nerve stumps. The brain stems were harvested, sectioned, and examined for fluorolabeling. The LMNs were quantified, and their 3-dimensional position within the nucleus ambiguus was mapped.

RESULTS

Labeling of the RLN was consistent regardless of the labeling agent used. A mean of 243 LMNs was documented for the RLN. The SLN labeling with FR was consistent and showed a mean of 117 LMNs; however, FG proved to be highly variable in labeling the SLN. The SLN LMNs lie rostral and ventral to those of the RLN. In the sham surgical condition, FG was noted to contaminate adjacent tissues--in particular, in the region of the SLN.

CONCLUSIONS

Fluorolabeling is an effective tool to locate and quantify the LMNs of the RLN and SLN. The LMN positions and counts were consistent when FR was used in labeling of either the RLN or the SLN. Fluoro-Gold, however, because of its tendency to contaminate surrounding structures, can only be used to label the RLN. Also, as previously reported, the SLN LMNs lie rostral and ventral to those of the RLN. This information results in further clarification of a rat model of RLN injury that may be used to investigate the effects of neurotrophic factors on RLN reinnervation.

The Otolaryngologist’s Role in Management of Aspiration: A Practical Review

Program Description: Aspiration pneumonia is a major problem in the geriatric population, in patients who are hospitalized long term, and for people with head and neck cancer. It is the second most common type of nosocomial infection, resulting in massive mortality and morbidity; in the elderly, the mortality rates range from 20% to 50%, with a rate as high as 80% in some studies. The health care costs associated with aspiration pneumonia are staggering. While aspiration pneumonia is often due to oropharyngeal or laryngeal disorders, the role of the otolaryngologist in diagnosing and managing aspiration can vary significantly; this purely clinical miniseminar will focus on how the general otolaryngologist can maximally contribute to the care of patients with aspiration. The panelists will discuss the following: 1) The practical value of multiple diagnostic modalities will be reviewed, including fiberoptic laryngoscopy, transnasal esophagoscopy (TNE), modified barium swallow and other radiological imaging, functional endoscopic evaluation of swallowing (FEES), sensory testing, pH and impedance probes, and high resolution manometry; 2) in-office evaluation for surgical decision making; 3) when to perform a tracheotomy or refer for a gastrostomy tube; 4) nonsurgical treatment including swallowing therapy, stents, salivary control, injection of botulism toxin, and electrical stimulation; 5) surgical treatment including laryngeal framework surgery, cricopharyngeal myotomy, laryngeal suspension, laryngeal closure procedures, and sensory reinnervation. Illustrative cases will also be presented to highlight common dilemmas and challenges.

Educational Objectives: 1) Describe how in-office evaluation and procedures are useful for decision making in medical and surgical treatment. 2) Understand the value of different diagnostic modalities. 3) Describe medical and surgical treatments for aspiration.

Atypical and disparate presentations of laryngeal sarcoidosis

Sarcoidosis is a multisystem chronic granulomatous disease of unknown cause that typically affects patients between 20 and 40 years of age. Laryngeal involvement most frequently involves the supraglottis and presents with dyspnea. We present a retrospective review of 4 patients with previously undiagnosed sarcoidosis who presented with atypical signs and symptoms of sarcoidosis: dysphonia with isolated vocal fold involvement; cough and globus pharyngeus; pediatric sarcoidosis; and severe bilateral vocal fold paresis and dysphagia. Our aim is to highlight disparate presentations of laryngeal sarcoidosis, as well as the treatment options. Laryngeal sarcoidosis may present with atypical signs and symptoms and occasionally presents in pediatric patients. A high degree of suspicion is necessary for a correct diagnosis in these patients. Early diagnosis and proper management of laryngeal sarcoidosis is important, as the symptoms are debilitating and possibly life-threatening. Treatment may consist of local and systemic chemotherapy, and adjunctive procedures.

Evaluation of Functional Recovery of Recurrent Laryngeal Nerve Using Transoral Laryngeal Bipolar Electromyography: A Rat Model

Objectives:

We developed a standardized method of minimally invasive transoral laryngeal (ToL) bipolar electromyography (EMG) for evaluation of recurrent laryngeal nerve (RLN) recovery after a controlled crush injury in a rat model.

Methods:

Ten 200- to 250-g Sprague-Dawley rats underwent a controlled crush injury to the left RLN performed with 60 seconds of use of a calibrated aneurysm clamp with a closing force of 0.61 N. Serial ToL bipolar EMG was performed on adductor muscles and the posterior criocoarytenoid muscle during spontaneous vocal fold motion under anesthesia. Each animal underwent ToL EMG immediately after surgery and 1, 3, and 6 weeks after surgery.

Results:

The EMG signals showed normal motor unit potentials and recruitment patterns 3 weeks after crush injury. Endoscopic evaluation of vocal fold mobility yielded consistently normal findings 6 weeks after crush injury.

Conclusions:

We have developed a standardized method of crush injury to the rat RLN model and a minimally invasive transoral bipolar spontaneous EMG technique to serially evaluate and follow nerve injury and recovery in rats. This model is intended to simulate intraoperative RLN injury, to elucidate the electrophysiological events that occur during nerve recovery, and to form the basis for studying agents to enhance such recovery.

Current diagnostic and management trends for recurrent respiratory papillomatosis

PURPOSE OF REVIEW

The purpose of this review is to discuss recent literature regarding diagnostic and management trends for recurrent respiratory papillomatosis (RRP) published within the past year. This includes a discussion of new information regarding the epidemiology and pathogenesis of RRP and an update on adjuvant therapy and new surgical techniques.

RECENT FINDINGS

Epidemiological studies have confirmed that juvenile-onset RRP is the most common and most aggressive form of the disease. Age at diagnosis is the most important determinant of disease severity, with younger patients requiring significantly more annual surgeries and more likely to have multicentric disease. Distal tracheal or pulmonary RRP is rare, but carries a significant increase in morbidity and mortality. Research into the pathogenesis of RRP has focused on the genetics of HPV infection and host-virus interactions, suggesting a genetic basis for host susceptibility to RRP. At the present time, surgery remains the mainstay of treatment for RRP. However, recurrence after surgery is common and the search for effective adjuvant therapies is ongoing. The antiviral drug cidofovir has demonstrated efficacy against RRP and is considered a promising new adjuvant treatment of this disease. In an attempt to minimize the untoward effects of surgery, the pulsed-dye laser (PDL) has emerged as a safe and efficacious treatment for select patients with RRP.

SUMMARY

While a cure for RRP remains elusive, there has been substantial progress in the diagnosis and management of this disease. Significant advances in clinical and basic science research have dramatically improved our understanding of the epidemiology and pathogenesis of the disease and led to the development of promising new adjuvant therapies and surgical techniques. This has translated to an improved quality of life for many patients with RRP.