OBJECTIVE: To test the feasibility of contrast-enhanced ultrasound (CEUS)-guided sentinel lymph node biopsy (SNB) of the head and neck in a porcine model. STUDY DESIGN AND SETTING: In this prospective, nonrandomized study, methylene blue and Sonazoid were injected into the lateral tongue or floor of mouth (FOM) of four swine. Real-time CEUS was used to identify contrast in the lymphatic channels flowing to the sentinel lymph node (SLN). Endoscopic or open SNB was performed. Neck dissection was then performed, and the residual nodal packet was examined for remaining contrast-enhancing or blue dye-stained nodes. RESULTS: In all eight procedures, the SLN was visualized with ultrasound and blue dye. Seven procedures identified a single SLN, and one identified two SLNs. Subsequent neck dissections revealed no other nodes containing methylene blue or contrast in the nodal specimen or operative bed. CONCLUSION/SIGNIFICANCE: CEUS-guided SNB of the head and neck in swine is feasible, with success comparable to blue dye-guided SNB. This technique may offer several advantages over traditional techniques, and warrants further study.

OBJECTIVE: To assess the feasibility of endoscopic sentinel node biopsy (SNB) using a tracer dye in a pig model. STUDY DESIGN AND SETTING: This was a prospective, nonrandomized experimental study in Yorkshire pigs. The posterolateral tongues of three animals were injected with a one-to-one solution of carbon dye to methylene blue dye. Endoscopic SNB was performed and stained lymph nodes identified and retrieved, followed by an open dissection to recover any remaining nodes. Specimens were analyzed by a pathologist for staining, size, and structural integrity. RESULTS: Six unilateral endoscopic SNBs were performed without complications. During endoscopic dissection, gross blue-staining of a sentinel node was noted in four of six dissections (66%). One of six sentinel nodes demonstrated histologic evidence of carbon staining. Structural integrity of all nodes was intact upon histological evaluation. CONCLUSION/SIGNIFICANCE: Endoscopic cervical SNB in pigs is feasible but has limitations based on lymph node size and reliability of tracer dyes. Further study is warranted to perfect tracer dyes and retrieval methods to improve this technique.

OBJECTIVES: We evaluated lymphosonography, or contrast-enhanced, ultrasonography (US)-guided sentinel lymph node (SLN) detection, as a technique for demonstrating the lymphatic drainage of the thyroid gland. METHODS: In this prospective animal study, four 50-kg Yorkshire swine underwent transcutaneous injection of a US contrast agent and methylene blue dye into the thyroid gland. Contrast-enhanced US was used to identify draining lymphatic channels and SLNs. Sentinel node biopsy was conducted. Subsequently, bilateral neck and upper mediastinal dissection was carried out. RESULTS: In 3 of 4 cases, a blue dye-positive and US contrast-positive SLN was identified. We identified SLNs in level IV in 2 cases. One case revealed 2 adjacent nodes in the superior mediastinum. In 1 case, a lymphatic channel was identified traveling into the mediastinum, but exposure of the SLN could not be obtained. No residual blue dye-positive or US contrast-positive nodes were identified on subsequent dissection. CONCLUSIONS: Lymphosonography of the thyroid gland in a porcine model correlates well with blue dye-guided sentinel node biopsy and is technically feasible, although in some cases access to the SLN may be difficult. This technique could potentially enable a detailed analysis of thyroidal lymphatic drainage if applied to humans.

The impact of chronic rhinosinusitis (CRS) on the olfactory mucosa (OM) is dramatic. Cellular profiles and epithelial integrity in OM biopsies were evaluated using histological and immunohistochemical methods to define a strategy for future histological studies of CRS. We have examined nasal biopsies of 54 CRS patients (18-63 years old) and have defined specific histopathological patterns of the OM: normal pseudostratified, goblet cell hyperplasia, squamous metaplasia, and erosion. Goblet cell hyperplasia was most similar to a normal pseudostratified OM pattern but with goblet cells intermixed in the apical layers. Squamous metaplasia exhibited an absence of olfactory supporting cells and had olfactory sensory neurons that were morphologically abnormal. It is unknown if these neurons would be functional in this type of tissue transformation. The pattern of erosion exhibited a severe loss of epithelial layers and a higher prevalence of infiltrating inflammatory cells within the olfactory epithelium when compared to the other OM patterns. Although it is not known if the OM patterns we have noted correspond to specific stages or distinct pathways of the disease, the template proposed here can be used in further studies to understand how the histopathological progression of CRS relates to olfactory loss and the response to treatment.

Few studies have examined the induction of squamous metaplasia in human olfactory nasal tissue caused by tobacco use and the implications it may have for olfaction, particularly when there are pre-existing insults, such as chronic rhinosinusitis (CRS). Quantitative histopathological analyses were performed on Alcian blue- and H&E-stained sections of nasal biopsies taken from the upper aspect of the middle turbinate of CRS patients. Chronic rhinosinusitis patients who were current smokers had a predominance of squamous metaplasia in the olfactory sensory epithelium, whereas CRS patients who were nonsmokers and were not exposed to secondhand cigarette smoke had a prevalence of goblet cell hyperplasia. In spite of this difference, the groups did not differ significantly in olfactory threshold sensitivity. The impact of primary cigarette smoke on olfaction and a possible role of squamous metaplasia in preserving olfactory neurogenesis are discussed.

OBJECTIVE: To test the feasibility of a novel contrast-enhanced ultrasound (CEUS) technique, or lymphosonography, for sentinel node biopsy (SNB) of the supraglottis in a porcine model. STUDY DESIGN AND SETTING: In this prospective, nonrandomized animal study, blue dye and ultrasound contrast agent were injected into the supraglottis in seven 50-kg Yorkshire swine. Transcutaneous CEUS was used to identify real-time lymphatic flow of contrast through lymph channels (LC) to the sentinel lymph node (SLN). SNB was carried out, visually identifying a blue node, with the assistance of intraoperative CEUS. Bilateral modified radical neck dissections were performed to search for any residual contrast-positive or blue SLNs. RESULTS: In each case, at least one SLN was identified by preoperative CEUS. A total of 12 nodes were identified on preoperative CEUS, and 11 of 12 nodes were stained with blue dye (91.7%). No residual blue or contrast-positive nodes were identified on neck dissection. CONCLUSIONS: Lymphosonographic SNB of the supraglottis in a porcine model is technically feasible, and yields results comparable to traditional blue dye-guided techniques. No "shine-through" effect or nonsequential nodal enhancement occurred. This technique holds promise for sentinel node biopsy and allows a novel method for in vivo investigation of the lymphatic system.

Differentiated thyroid cancer is characterized by an excellent long-term prognosis, which unlike other head and neck carcinomas, is not influenced definitively by regional lymph node metastasis. The relative rarity of the disease, together with its tendency for delayed metastasis and its low mortality, makes a prospective randomized trial comparing treatment outcomes difficult. As a result, the effect of cervical lymph node metastases on survival is unclear, making meaningful recommendations for their management somewhat subjective. This article discusses guidelines for the management of the neck in differentiated.

Objective: Routine use of intraoperative pathologic examination (IOPE), including frozen section (FS) and scrape preparation cytology (SPC), during diagnostic thyroid lobectomy continues to be a source of controversy. We sought to better delineate the usefulness and cost-benefit ratio of IOPE in the context of cytologically diagnosed cellular follicular lesion (CFL) or follicular neoplasm (FN). Design: Records of 205 patients who underwent thyroidectomy for cytologically diagnosed FN or CFL between 1997 and 2005 were retrospectively reviewed. IOPE results, patient demographics, and tumor characteristics were correlated to final histopathologic diagnoses. Sensitivity, specificity, predictive values, accuracy, and costs of IOPE were calculated. Main outcome: IOPE correctly identified 3 of 16 follicular carcinomas and 9 of 36 papillary carcinomas. Sensitivity, specificity, and accuracy were 23%, 99%, and 78%, respectively. On univariate analysis, malignancy risk among follicular nodules did not correlate with age, gender, or nodule size. On multivariate analysis, nodule size was predictive of malignancy (p < 0.05). Over the entire patient series, routine IOPE resulted in a net cost savings of $74,304.33. Conclusions: IOPE reduced costs and limited the number of completion thyroidectomies necessary. IOPE is specific, cost effective, and of minimal additional risk when performed routinely for patients with CFL or FN.

BACKGROUND: Mechanical obstruction of odorant flow to the olfactory neuroepithelium may be a primary cause of olfactory loss in nasal-sinus disease patients. Surgical removal of nasal obstruction may facilitate the recovery of olfactory ability. Unfortunately, quantifying the functional impact of nasal obstruction and subsequent surgical outcomes using acoustic rhinometry, rhinomanometry, or CT scans is inadequate. METHODS: Using computational fluid dynamics (CFD) techniques, we can convert patient CT scans into anatomically accurate 3D numerical nasal models that can be used to predict nasal airflow and odorant delivery rates. These models also can be rapidly modified to reflect anatomic changes, e.g., surgical removal of polyps. RESULTS: CFD modeling of one patient's nose pre- and postsurgery showed significant improvement in postsurgical ortho- and retronasal airflow and odorant delivery rate to olfactory neuroepithelium (> 1000 times), which correlated well with olfactory recovery. CONCLUSION: This study has introduced a novel technique (CFD) to calculate nasal airflow dynamics and its effects on olfaction, nasal obstruction, and sinus disease. In the future, such techniques may provide a quantitative evaluation of surgical outcome and an important preoperative guide to optimize nasal airflow and odorant delivery.

BACKGROUND: Intraoperative neuromonitoring (IONM) of the recurrent laryngeal nerve (RLN) has recently been more frequently applied in thyroid surgery. However, concerns have been raised regarding the safety and optimal intensity of electrical nerve stimulation. METHODS: Eight piglets were enrolled, and electrically evoked electromyography (EMG) was recorded from the vocalis muscles via endotracheal surface electrodes. The baseline EMG was measured and continuous pulsatile stimulations were performed on the vagus nerve and RLN for 10 minutes. Changes of EMG waveform and cardiopulmonary status were analyzed. RESULTS: A dose-response curve existed with increasing EMG amplitude as stimulating current was increased, with maximum amplitude elicited on vagal and RLN stimulation at <1 mA. No obvious EMG changes and untoward cardiopulmonary effects were observed after the stimulation. CONCLUSIONS: Electrical stimulation is safe during IONM in this porcine model. Minimal current that required generating the maximal evoked EMG, approximately 1 mA in this study, can be selected to minimize the risk of nerve damage and cardiopulmonary effects.(c) 2010 Wiley Periodicals, Inc. Head Neck, 2010.

BACKGROUND: Translumenal endoscopic interventions via so-called natural orifices are gaining increasing interest because they allow surgical treatment without any incision of the skin. Moreover, minimally invasive procedures have found their way into thyroid and parathyroid surgery. Our goal was to develop a new access for thyroid and parathyroid resection via an entirely transoral approach. METHODS: We managed to find an entirely transoral sublingual access to the thyroid region in pigs and human cadavers. Using a modified rigid rectoscope (oraloscope) hemithyroidectomies as well as resection of parathyroid glands were performed via this new approach. Preparation and resection was performed using conventional laparoscopic instruments. In living pigs, integrity of the recurrent laryngeal nerve after resection could be documented by neuromonitoring. An absorbable suture was used to seal the mucosal incision. RESULTS: First, hemithyroidectomy was performed via the transoral access in 10 porcine cadavers, then in 10 living and orally intubated pigs, and finally in five human corpses. In humans, resection of parathyroid glands also was performed. We gained access to the thyroid region by blunt dissection of the layer behind the hyoid bone and the strap muscles of the neck. We did not observe any complication during the insertion, resection, and removal part of the new procedure. CONCLUSIONS: Entirely transoral thyroid and parathyroid surgery via sublingual access seems to be feasible. However, further investigations are needed to evaluate the safety of the new technique, especially potential and clinically relevant contamination of the access route has to be excluded.

OBJECTIVE: To determine whether nerve integrity monitor testing during thyroidectomy predicts recurrent larygeal nerve (RLN) function after surgery. DESIGN: Prospective cohort outcomes study PATIENTS: The study included 210 consecutive patients with thyroid abnormalities who underwent thyroidectomy. METHODS: All patients were intraoperatively monitored with a nerve integrity monitoring system (Xomed NIM II; Medtronic Inc, Fridley, Minnesota), and their vocal cord function was assessed with fiberoptic laryngoscopy before and after surgery. Normal and impaired vocal cord function were compared using an independent t test with respect to postoperative vocal cord mobility, length of the RLN dissection, and the minimum stimulus needed to generate a response at the completion of surgery. RESULTS: There was a statistically significant difference between the stimulus in milliamperes required to stimulate normal vs abnormal functioning nerves at the completion of the procedure at the cricoarytenoid joint (P =.02) and at the distal end of the RLN dissection (P <.01). A greater length of dissected nerve was associated with normal vocal cord function; however, it was not statistically significant (P =.07). CONCLUSION: These data suggest that an RLN that responds at lower-intensity stimulation (</=0.5 mA) at the end of thyroid surgery is associated with normal vocal cord mobility.

Accidental injury to the recurrent laryngeal nerve is a common complication of thyroid surgery. Different mechanisms of injury have been described, such as mechanical, electrical, or thermal. Retrosternal operations, secondary bleeding requiring wound revision, or neoplastic tumors are also frequent causes of this complication. Intraoperative direct stimulation of suspected nerve structures as well as vagal nerve stimulation have been proposed to avoid the injury. The effect of stimulation can be assessed by direct observation of the vocal cords (direct laryngoscopy or fiberoscopy via a laryngeal mask airway), or electromyography of the posterior cricoarytenoid muscle. All of these methods limit the use of muscle relaxants during anaesthesia. Details of anaesthetic management are presented.

We tested the feasibility of the sublingual transoral access for thyroid resection including the monitoring of the recurrent laryngeal nerve (RLN) in a porcine model. We performed a prospective, nonrandomized proof-of-concept experimental investigation on transoral thyroid resection in a porcine model with monitoring of the RLN. Ten endoscopic transoral thyroidectomies were performed in 10 pigs using a neuromonitoring system. First, the RLN was identified visually and then confirmed with the neuromonitoring system bilaterally. A complete transoral thyroid resection was achieved in all living pigs. The average operation time was 50 min. The neuromonitoring system permitted to prove the regular function of the RLN on both sides after the removal of the thyroid gland. The pigs were observed for another 2 h postoperatively. Consequent monitoring of the RLN in endoscopic transoral thyroid resection is possible. This system can be a helpful support to identify the nerve when the anatomic situation due to using an endoscopic access is more complicated. It proved to be a safe procedure in living pigs. Our results might be useful for using the neuromonitoring system as a standard system in endoscopic thyroid surgery for the maximal safety of the patient in these new procedures.

Endoscopically assisted, minimally invasive techniques to regions without a natural cavity require insufflation with carbon dioxide (CO2). In the neck region this may impair hemodynamics, blood gas homoeostasis, cerebral blood circulation and increase the intracranial pressure. An exclusively endoscopic unilateral subplatysmal approach to the submandibular region was investigated in nine mini-pigs randomized to three groups. On both neck sides, within a 14 day interval, the subplatysmal space was inflated with CO2 at 10 mmHg, 20 mmHg (1.33/2.66x10(3)Pa) or 20 mmHg (2.66x10(3)Pa) combined with mechanical suspension. Data for hemodynamic and blood gas parameters, gas volumes, and intracranial pressure were obtained preoperatively, 30min after onset and 10min postopeatively. In a pocket created by insufflation of 20 mmHg (2.66x10(3)Pa), exposition and resection of the submandibular gland were accomplished easily. The elevation procedure had technical disadvantages. The mean operation time was 48.9min. Unilateral subplatysmal carbon dioxide insufflation of the submandibular neck region up to 20 mmHg (2.66x10(3)Pa) did not affect physiological parameters. As an exclusive endoscopical approach for unilateral surgery of the submandibular region, the use of inflation pressures of up to 20 mmHg (2.66x10(3)Pa) might be considered.