Sternohyoid Research Articles

Arcuate anterior jugular vein: a rare case report and its clinical relevance.

The present study describes a rare anatomical variation of the anterior jugular vein (AJV) and discusses its clinical relevance. A head and neck specimen fixed in 10% formaldehyde from a 42-year-old female cadaver was submitted to angio technique with pre-vulcanized latex and water-soluble ink. During a routine dissection for the discipline of topographic anatomy, the presence of an arcuate AJV was detected in the anterior triangle of the neck. An arcuate AJV was formed by the confluence of the submental and facial veins in the left submandibular region, which presented a complex network of anastomoses superficially to the left submandibular gland. After its origin, this vessel curved to the right at the level of the laryngeal prominence and followed the medial border of the right sternohyoid muscle to flow into the right AJV. In this topography, the arcuate AJV was located between the sternocleidomastoid muscle's anterior margin and the thyroid gland's right lobe. The presence of anastomoses between the two AJVs communicating the submandibular triangles was not detected. The arcuate AJV is a relevant anatomical variant in the superficial venous drainage of the neck that should be known by head and neck surgeons and radiologists to avoid surgical iatrogenic events.

Impaired Upper Airway Muscle Function with Excessive or Deficient Dietary Intake of Selenium in Rats.

Obstructive sleep apnoea (OSA) involves impaired upper airway muscle function and is linked to several pathologies including systemic hypertension, daytime somnolence and cognitive decline. Selenium is an essential micronutrient that exerts many of its effects through selenoproteins. Evidence indicates that either deficient or excessive dietary selenium intake can result in impaired muscle function, termed nutritional myopathy. To investigate the effects of selenium on an upper airway muscle, the sternohyoid, rats were fed on diets containing deficient, normal (0.5 ppm sodium selenite) or excessive (5 ppm selenite) selenium for a period of two weeks. Sternohyoid contractile function was assessed ex vivo. Serum selenium levels and activity of the glutathione antioxidant system were determined by biochemical assays. The abundance of three key muscle selenoproteins (selenoproteins -N, -S and -W (SELENON, SELENOS and SELENOW)) in sternohyoid muscle were quantified by immunoblotting. Levels of these selenoproteins were also compared between rats exposed to chronic intermittent hypoxia, a model of OSA, and sham treated animals. Although having no detectable effect on selected organ masses and whole-body weight, either selenium-deficient or -excessive diets severely impaired sternohyoid contractile function. These changes did not involve altered fibre size distribution. These dietary interventions resulted in corresponding changes in serum selenium concentrations but did not alter the activity of glutathione-dependent antioxidant systems in sternohyoid muscle. Excess dietary selenium increased the abundance of SELENOW protein in sternohyoid muscles but had no effect on SELENON or SELENOS. In contrast, chronic intermittent hypoxia increased SELENON, decreased SELENOW and had no significant effect on SELENOS in sternohyoid muscle. These findings indicate that two-week exposure to selenium-deficient or -excessive diets drastically impaired upper airway muscle function. In the sternohyoid, SELENON, SELENOS and SELENOW proteins show distinct alterations in level following exposure to different dietary selenium intakes, or to chronic intermittent hypoxia. Understanding how alterations in Se and selenoproteins impact sternohyoid muscle function has the potential to be translated into new therapies for prevention or treatment of OSA.

Functional involvement of the sternohyoid muscle during breathing and swallowing in rats.

The sternohyoid muscle depresses the hyoid bone, but it is unclear whether the muscle contributes to respiratory and swallowing mechanisms. This study aimed to clarify whether the sternohyoid muscle participates in the respiration and swallowing reflex and how the activity is modulated in two conditions: with airway stenosis and with a fixed sternohyoid muscle length. Electromyographic activity in the sternohyoid, digastric, thyrohyoid, and diaphragm muscles was recorded in anesthetized rats. The sternohyoid muscle activity was observed in the inspiratory phase and during swallowing, and was well coordinated with digastric and thyrohyoid muscle activity. With airway stenosis, the respiratory activity per respiratory cycle was facilitated in all assessed muscles but the facilitation of activity per second occurred only in the digastric, thyrohyoid, and sternohyoid muscles. With airway stenosis, the swallowing activity was facilitated only in the digastric muscle but not in the thyrohyoid and sternohyoid muscles. Swallowing activity was not observed in the sternohyoid muscle in the condition with the sternohyoid muscle length fixed, although increased inspiratory activity remained. The current results suggest that 1) the sternohyoid muscle is slightly activated in the inspiratory phase, 2) the effect of airway stenosis on respiratory function may differ between the upper airway muscles and diaphragm, and 3) swallowing activity in the sternohyoid muscle is not dominantly controlled by the swallowing central pattern generator but instead occurs as a myotatic reflex.NEW & NOTEWORTHY We found that the sternohyoid muscle was activated in the inspiratory phase. However, increased airway resistance had different effects on the extrathoracic muscles than on the diaphragm. The swallowing activity of the sternohyoid disappeared when the muscle length was fixed. These findings suggest that the sternohyoid muscle may be activated not by the swallowing central pattern generator but as a myotatic reflex.

Unusual anatomical variants of infrahyoid muscles - case report.

Anatomical anomalies of neck muscles are rarely observed and usually comprise variations of digastric and omohyoid muscles. Neck muscles' abnormalities might be correlated with embryological development and are observed in individuals with aneuploidies such as Edward's syndrome (18-trisomy) or Down syndrome (21-trisomy). Some infrahyoid muscles are important landmarks during surgery, therefore their anatomical variations of these muscles are related to higher risk of surgical complications. Herein, we present a rare case of infrahyoid muscles anomalies found during routine dissection of male cadaver. Redundant muscle bellies of sternohyoid muscle (sternohyoid azygos muscle), presence of levator glandulae thyroideae and also one hypoplastic superior belly of the omohyoid muscle were observed. Presence of muscle fibers within found structures was confirmed using Masson's trichrome staining method.

The previously undescribed variant of the thyrohyoid muscle and its potential impact on surgical procedures

The thyrohyoid muscle belongs to the infrahyoid group located in the carotid triangle. It normally originates from thyroid cartilage and inserts into hyoid bone. Quite often, it is continuous with the sternohyoid muscle. Furthermore, there are variants that have their origin in the cricoid cartilage only, however, this occurs very rarely. During anatomical dissection, a two-headed variant of this muscle was found. One head had its origin in the cricoid cartilage and the other in the thyroid cartilage. This variant of thyrohyoid had not been previously described in the available literature. Therefore, we believe that it may be referred to as the cricothyrohyoid muscle. As the thyrohyoideus is often used as a landmark during surgical procedures in the prelaryngeal area and as a muscle graft, a thorough knowledge of its anatomy and variation is extremely important. We speculate that the two-headed version of this muscle may be problematic during surgical procedures in this region, however, it may also provide more options as a muscular graft.

Advanced Age Impairs the Neuromuscular Control of Peak Inspiratory Performance in Mice

Respiratory muscle wasting is known to occur in ageing adults resulting in a decreased capacity for force production and an associated reduction in high-threshold respiratory performance. Dysfunction of the respiratory musculature in this manner may contribute to an increased susceptibility to respiratory complications frequently observed in older populations. The objective of the current study was to characterise the respiratory phenotype during advanced age to assess the impact of sarcopenia on the neuromuscular control of respiratory performance. Male wild type (BL10) mice were studied at 6-months and 24-months, representing young and old age cohorts, respectively. In anaesthetised animals, inspiratory pressure and contemporaneous obligatory and accessory respiratory muscle electromyography (EMG) activities were measured during baseline and sustained tracheal occlusion (n = 9 young; n = 8 old). Diaphragm muscle contractile performance was assessed ex-vivo via tissue bath preparations (n = 8 young; n = 8 old). Furthermore, diaphragm and limb muscle tissues were harvested and snap frozen for subsequent structural and molecular analyses which will assess potential differences in cross-sectional area and relative fibre type composition. Peak inspiratory pressure was significantly reduced in 24-month-old compared to 6-month-old mice (P < 0.0001). Associated EMG activity was significantly lower (P < 0.05) in obligatory (external intercostal; parasternal) and accessory (cleidomastoid; scalene; trapezius; sternomastoid; sternohyoid) muscles of breathing in the old group compared to the young. Diaphragm EMG amplitude was not different between the groups. No differences were observed in the force-generating capacity of the diaphragm between young and old cohorts. Our preliminary results suggest an impairment in the neuromuscular control of the respiratory system during peak performance which apparently precedes the age-related decline in diaphragm muscle force generating capacity. Our further histological and molecular analyses will provide additional insight into the nature of this respiratory phenotype in advanced age. This work was funded by the Department of Physiology, UCC. B.T. Murphy is funded by an Irish Research Council Doctoral Scholarship. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Quantitative comparison of three thyroidectomy approaches on neck muscles, voice, and swallowing functions

ObjectiveThis study compares endoscopic thyroidectomy by gasless unilateral axillary approach (ETGUA) and sternocleidomastoid leading-edge approach (SLEA) with conventional open thyroidectomy (COT) in hemithyroidectomy. The main focus is on the protection of neck muscles (sternocleidomastoid, omohyoid, sternothyroid) and the postoperative function of voice and swallowing yielded through these common approaches. MethodsA total of 302 patients who underwent hemithyroidectomy were enrolled and divided into three groups: ETGUA (n = 101), SLEA (n = 100), and COT (n = 101). Ultrasound was used to measure the thickness of bilateral neck muscles, including the sternocleidomastoid, omohyoid, and sternothyroid. The changes in thickness on the surgical side compared to the non-surgical side. Analyzed factors included muscle thickness changes, Swallowing Impairment Score (SIS), Voice Handicap Index (VHI), Scar Cosmesis Assessment and Rating (SCAR), Neck Incision Index (NII), surgery duration, drainage volume, hospitalization, and number of lymph nodes. ResultsThe clinical characteristics among the three groups were consistent except for differences in sex, age, and BMI. Metrics such as sternocleidomastoid muscle, NII, hypocalcemia, postoperative PTH, transient hoarseness, and number of lymph nodes showed no significant differences among the three groups. However, significant differences were found in the duration of surgery, drainage volume, hospitalization period omohyoid muscle, Sternohyoid muscle, VHI, SIS, and SCAR (all p < 0.001). ConclusionIn comparison to COT, ETGUA and SLEA demonstrate superiority in protecting neck muscles and preserving voice and swallowing function without compromising surgical safety or radicality.

Swallowing-related muscle inflammation and fibrosis induced by a single dose of radiation exposure in mice

BackgroundAlthough radiotherapy is commonly used to treat head and neck cancer, it may lead to radiation-associated dysphagia (RAD). There are various causes of RAD, however, the mechanism has not yet been fully identified. Currently, the only effective treatment for RAD is rehabilitation. Additionally, there are few available animal models of RAD, necessitating the development of new models to establish and evaluate RAD treatments. We hypothesize that radiation-induced neck muscle fibrosis could be one of the causes of RAD due to impairment of laryngeal elevation. Therefore, in this study, we focused on the changes in inflammation and fibrosis of the strap muscles (Sternohyoid, Sternothyroid, and Thyrohyoid muscles) after a single-dose irradiation. This research aims to provide a reference animal model for future studies on RAD.ResultsCompared to control mice, those treated with 72-Gy, but not 24-Gy, irradiation had significantly increased tumor necrosis factor-α (TNF-α) (p < 0.01) and α-smooth muscle actin (αSMA) (p < 0.05) expression at 10 days and significantly increased expression levels of motif chemokine ligand-2 (CCL2), α-SMA, tumor growth factor-β1 (TGF-β1), type1 collagen, and interleukin-1β (IL-1β) (p < 0.05) in the muscles at 1 month by real-time PCR analysis. The results of immunohistochemistry showed that the deposition of type 1 collagen gradually increased in extracellular space after radiation exposure, and the positive area was significantly increased at 3 months compared to non-irradiated control.ConclusionsA single dose of 72-Gy irradiation induced significant inflammation and fibrosis in the strap muscles of mice at 1 month, with immunohistochemical changes becoming evident at 3 months. This cervical irradiation-induced fibrosis model holds potential for establishing an animal model for RAD in future studies.Level of evidenceN/A.

Application of acellular dermal matrix in prevention of laryngeal stenosis in glottic carcinoma

Objective:To investigate the effect of acellular dermal matrix in preventing laryngeal stenosis in glottic carcinoma patients. Methods:Fifty-five patients with glottic carcinoma（T2, T3） from February 2018 to December 2022 were divided into experimental group（28 cases） and control group（27 cases） according to their wishes. Acellular dermal matrix was placed in the operation cavity in the experimental group after laryngofission, while control group 12 cases were sutured by pulling the upper and lower edges, 15 cases were repaired with sternohyoid muscle fascia flap. Results:In the experimental group, 1 case had laryngeal stenosis caused by laryngeal mucosa swelling after operation, and extubated successfully after symptomatic treatment. In the control group, 7 cases had laryngeal stenosis after operation, of which 3 cases were caused by granulation tissue hyperplasia in laryngeal cavity, and extubated after symptomatic treatment. 2 cases extubated after operation suffered from progressive dyspnea during radiotherapy, and underwent tracheotomy again, extubation successful after treatment. 2 cases caused by laryngeal mucosa swelling, after symptomatic treatment, one case was successfully extubated, and one case had long-term intubation. The laryngeal stenosis rate of the experimental group was 3.6%（1/28） , which was lower than control group 25.9%（7/27）, and the therapeutic effect of the experimental group was significantly better than control group （χ²=5.526, P=0.019）. Conclusion:Implanting acellular dermal matrix in the operation cavity of glottic carcinoma can reduce the occurrence of laryngeal stenosis and have satisfactory preventive effect on laryngeal stenosis.

Reconstruction of laryngeal function by thyroid cartilage fenestration and draw-out resection followed by internal fixation with titanium microplates for early glottic carcinoma: a novel and efficient surgical approach.

To explore the clinical effectiveness of reconstructing laryngeal function using thyroid cartilage fenestration and "draw-out" resection, supplemented by internal fixation with titanium microplates in early glottic carcinoma. Data from 99 patients with glottic carcinoma treated in the Second Affiliated Hospital of Fujian Medical University between January 2014 and September 2021 were retrospectively analyzed. Forty-eight patients who underwent thyroid cartilage fenestration and resection followed by internal fixation with titanium microplates for laryngeal function reconstruction were assigned to the thyroid cartilage fenestration group (TCF group), while the other 51 patients who underwent sternohyoid muscle and fascia repair for laryngeal function reconstruction were assigned to the sternohyoid muscle repair group (SMR group). Patients were followed up for 1-8 years. Data on postoperative phonatory function, respiratory function, swallowing function, and survival status were collected. Compared to the SMR group, patients in the TCF group showed better postoperative recovery in phonatory function and verbal communication (all P<0.05). In the TCF group, patients demonstrated stable respiration and the extubation rate was 100.00%, which was significantly higher than 82.35% in the SMR group (P<0.05). Patients in both groups showed good postoperative recovery of swallowing function (P>0.05). One-stage reconstruction of laryngeal function by thyroid cartilage fenestration and "draw-out" resection with adjuvant internal titanium microplate fixation in early glottic carcinoma demonstrates good postoperative recovery and good preservation of the laryngeal function.

Sternohyoid or sternocleidomastoid muscle flap for tracheoesophageal puncture closure in irradiated patients: A CARE case series

IntroductionA novel technique for tracheoesophageal puncture (TEP) closure is described in which the sternohyoid muscles are rotated and interposed between the tracheal and esophageal walls. The results of this technique are reported, following CARE guidelines, and compared with those obtained using the sternocleidomastoid flap. A literature review on the techniques previously described for TEP closure in irradiated patients is presented. Case seriesThe novel technique was performed in six patients in whom the infrahyoid muscles were preserved during total laryngectomy. All received adjuvant radiotherapy. Successful closure was achieved in three cases; in one case a small leak was noted after initial closure and was successfully managed with simple sutures; and the other two failures occurred in patients with diabetes. The sternocleidomastoid flap was performed in five patients (only one with previous radiation) and success was achieved in two patients. In another patient a micro-fistular orifice appeared six months after the operation. DiscussionThe sternohyoid muscles pose a low morbidity alternative to be considered in surgical TEP closure. Patient selection is a key factor to surgical success, and this technique should be reserved for small to moderate size fistulas and in the absence of multiple impaired wound healing conditions.

Intraoperative nerve stimulation during vagal nerve stimulator placement.

Vagal nerve stimulation (VNS) is a palliative treatment for refractory epilepsy and intraoperative nerve stimulation is applied to the vagal and other nerves to prevent electrode misplacement. We evaluated these thresholds to establish intraoperative monitoring procedures for VNS surgery. Forty-six patients who underwent intraoperative nerve stimulation during VNS placement were enrolled. The vagal nerve and other exposed nerves were electrically stimulated during surgery, and muscle contraction was confirmed by electromyography of the vocal cords and visual recognition of cervical muscle contraction. The nerve thresholds and the most sensitive parts of the vagal nerve were analyzed retrospectively. The stimulation of vagal nerves induced vocal cord responses in all 46 patients; the median thresholds of the most sensitive parts and all parts were 0.2 mA (range: 0.05-0.75 mA) and 0.25 mA (range: 0.15-1.5 mA), respectively. The medial middle region was identified as the most sensitive part of the vagal nerve in the majority of participants (82.5%). In 11 patients, other cervical nerves were stimulated and sternohyoid muscle contraction was induced with a median threshold of 0.35 mA (range: 0.1-0.7 mA) in eight patients, while sternocleidomastoid muscle contraction was induced with a median threshold of 0.2 mA (range: 0.1-0.2 mA) in three. Intraoperative stimulation of vagal nerves induces vocal cord responses with locational variations, and the middle part stimulation could minimize the stimulus intensities. The nerves innervating the sternohyoid and sternocleidomastoid muscles may be exposed during the procedure. Knowledge of these characteristics will enhance the effectiveness of this technique in future applications.

복장목뿔근에 대한 수동신장운동이 폐 기능에 미치는 영향

Purpose: This study aimed to investigate the effects of passive stretching exercise for the sternohyoid muscle, widely known as the accessory respiratory muscle, on pulmonary function. Methods: A total of 24 female university students without neurological, musculoskeletal, or cardiopulmonary dysfunction were included in this study. The subjects were randomly assigned to experimental (n=14) and control groups (n=10). Pulmonary function was assessed before and after passive stretching exercises using a spirometer (Pony FX, COSMED Inc., Rome, Italy). The experimental group performed 10 sets of three repetitions of passive stretching exercises for the sternohyoid muscle. The control group did not perform any exercise. Results: No significant changes in forced vital capacity and forced expiratory volume in one second were observed in both groups. However, a significant improvement in tidal volume, inspiratory capacity, and vital capacity (VC) was observed in the experimental group after passive stretching exercises, whereas no change was observed in the control group. Additionally, a significant improvement in maximal voluntary ventilation (MVV) was observed in the experimental group, whereas no change was observed in the control group. The changes in VC and MVV were higher in the experimental group than in the control group. Conclusion: Passive stretching exercises for the sternohyoid muscle can improve pulmonary function. In particular, they are effective in improving VC and MVV.

Precise and Facile Endotracheal Lung-tumor-implantation Mouse Model Visualized by GFP Expression.

In osteosarcoma, lung metastasis is a major cause of cancer-related death, as the 5-year survival rate for patients with metastases is approximately only 20-30%. To develop improved therapeutic strategies against lung-metastatic osteosarcoma, an experimental lung-tumor-implantation mouse model is needed for basic research. In the present study, we developed a precise and facile endotracheal lung-tumor-implantation technique. For establishment of the lung-tumor-implantation mouse model of metastatic osteosarcoma, 5 mice were used. A 15-mm longitudinal incision was made in the center of the neck to expose the salivary glands. The salivary glands were then split, exposing the trachea covered by the sternohyoid muscles. The trachea was then clearly exposed by cutting the sternohyoid muscles longitudinally. A 22 G gavage needle was tilted slightly toward the left side of the mouse and inserted from the oral cavity into the bronchus, with confirmation of the position of the tip of the gavage needle visualized through the tracheal wall, followed by injection of 0.5% crystal violet to first confirm the accuracy of endotracheal injection in the lung. A 143B-GFP cell suspension (2.0×106 cells/50 μl PBS) was then injected endotracheally in other mice. The procedure, including anesthesia and suturing, took approximately 10 minutes. The left lobe of the lung, in which crystal violet was injected endotracheally, was stained in 3 out of 3 mice (100%). 143B-GFP-osteosarcoma tumors were detected with GFP fluorescence in the left lobe of the lung in 3 out of 4 mice (75%), 5 weeks after endotracheal injection. One mouse died 4 weeks after 143B-GFP-cell implantation. This novel technique of establishing tumors in the lung via endotracheal injection of cancer cells is precise and facile and can be used widely, since neither a surgical microscope nor X-ray imaging are needed.

Topographic and anatomical analysis of sternohyoid muscle autograft in surgical treatment of facial paralysis lasting more than 18 months

Topographic and anatomical analysis of sternohyoid muscle autograft in surgical treatment of facial paralysis lasting more than 18 months

Pharyngeal Closure Reinforced With Sternohyoid and Omohyoid Muscle After Total Laryngectomy

Pharyngocutaneous fistula occurring after total laryngectomy is a bothersome complication as it can even cause a massive bleeding due to carotid artery rupture. Preoperative radiation, extensive diseases which need flap reconstruction, low albumin or hemoglobin level, history of smoking, or underlying diseases have been domestically reported to have a relationship with the condition. To reduce this complication, simultaneous coverage for the pharyngeal closure has been developed using flaps, such as the pectoralis major muscle, the radial forearm or the anterolateral thigh, which are distant from the radiation field. However, these methods need additional surgical techniques and times. Another method advocated is pharyngeal reinforcement using flaps that can be easily obtained from the same surgical field, such as the sternocleidomastoid or the infrahyoid muscle or the acellular dermal graft with relative significances. Here we suggest reinforcement of pharyngeal closure after total laryngectomy using the sternohyoid and omohyoid muscle flaps.

The Short Neck: Challenges and Techniques

Establishing a pleasant cervical contour in short-neck patients is of one the most difficult challenges for a facial plastic surgeon. Subplatysmal volume reduction, platysma tightening, and skin distribution adequately coupled with the middle third facelift are the pillars of the surgical approach. Additionally, treating the small chin, which is frequently observed in these patients, improves the overall result. In this paper, an objective method to define short-neck patients is offered. The applied surgical anatomy of the neck is revised. Innovative strategies to treat the supra and infrahyoid subplatysmal structures are presented, including the sternohyoid muscles plicature and the use of the interplatysmal/subplatysmal fat flap. A novel chin augmentation technique, using a subperiosteal en bloc fat graft is also introduced. A modified deep plane approach is described, including a continuous suture of the middle third fasciocutaneous flap. A combined lateral platysma tensioning with the sternocleidomastoid rejuvenation is demonstrated. Lastly, the hemostatic net is revisited as a critical approach to resolve the defying skin accommodation.

Giant Lipoma in the Lateral Neck Causing Internal Jugular Vein Deformity

Lipoma is one of the most common benign soft tissue tumors. However, giant lipomas compressing and deforming the neurovascular structure rarely occur in the lateral neck. A 70-year-old man visited our outpatient clinic for treatment of a visible painless neck mass that had been identified 2 years prior. Neck magnetic resonance imaging revealed that a 10 × 9 × 4 cm fatty mass located between the sternocleidomastoid and sternohyoid muscles invaded the carotid sheath. Under general anesthesia, the mass was excised without damage to the adjacent neurovascular structures. Upon histopathological examination, the mass was identified as a lipoma. During the surgery, enlargement of the internal jugular vein was observed under the resected mass. However, on ultrasound examination, the function of the internal jugular vein was evaluated as good. No recurrence or neurological and vascular complications were reported during a 6-month follow-up after the surgery. As a giant lipoma located in the deep layer of the lateral neck can deform important cervical structures, its impact on the surrounding structures should be carefully assessed preoperatively to minimize the rate of possible complications.

Comparison of Amplifiers Utilization in Instrumentation to Record Muscle Signals in the Neck for Electrolarynx Applications

Electrolarynx is an assistive technology commonly used by speech impaired people to speak. The speech impaired people who have lost their larynx (laryngectomee) or have damaged larynx use an electrolarynx device to be able to speak again. The use of the electrolarynx is generally equipped with a button to turn on and start the generation of sound from the electrolarynx. Several studies have tried to use other control methods by using the muscles in the neck, namely the sternohyoid muscle. Activation of the sternohyoid muscle has an influence on sound formation. The sternohyoid muscle is a small and long muscle so recording EMG (electromyograph) signals from this muscle is quite difficult. If the recording process of this signal can be carried out properly, then the electrolarynx control by empowering this muscle will be another solution in using the electrolarynx. In this study, instrumentation amplifier which is an important stage of recording EMG signals of neck muscle was tested and compared. There are two types of instrumentation amplifier tested. The first instrumentation amplifier uses a single IC from IC AD620 while the other is a combination circuit of IC OP07. The EMG signal in the subject's neck muscles was then recorded using the instrumentation amplifiers. The subject will sit down and pronounce the vowels "a", and "i". From the testing process, it was found that the average gain on IC AD620 (minimum 1.74362 volts and maximum 3.70538 volts) was greater than the gain on IC OP07 (minimum 0.57779 volts and maximum 1.71190 volts). IC AD620 also has an overall use area of 5.61 cm2 with the use of 4 external components. Thus, it can be concluded that the best instrumentation amplifier for recording EMG neck muscle for electrolarynx application is by using IC AD620.

Occult metastasis to the superficial level VI lymph nodes in papillary thyroid carcinoma.

This study aimed to evaluate the incidence and risk factors of occult metastasis to superficial level VI, defined as the space anterior to the strap muscles, including the lymph nodes between the sternocleidomastoid and sternohyoid muscles and suprasternal space lymph nodes. We studied 129 patients with papillary thyroid carcinoma who underwent thyroidectomy and neck dissection, including superficial level VI dissection. Of the 129 patients, 62 (48%) had lymph nodes in the harvested specimens of superficial level VI, and the mean number of lymph nodes retrieved was 1.9 ± 1.2. Occult metastasis to superficial level VI occurred in four patients (3.1%). No significant risk factors of superficial level VI occult metastasis were noted in multivariate analysis. Occult metastasis to superficial level VI was rare in patients with papillary thyroid carcinoma. Therefore, prophylactic dissection of superficial level VI may not be necessary for primary papillary thyroid carcinoma.