Large plunging schwannoma of the floor of the mouth involving the mylohyoid nerve: a case report and review of the literature.

Extracranial schwannomas are rare in the oral cavity, accounting for only 1% of all tumors of this type. This article presents a case study of a schwannoma arising from the mylohyoid nerve that presented as a large nodular swelling in the floor of the mouth extending into the submandibular space.

[Topographic features of lingual nerve and its relationship with other anatomical structures in maxillolingual groove].

By surgical interventions in maxillolingual groove area one should consider anatomical variations and topography of vessels, glands ducts and lingual nerve to prevent their injury. At the Department of Operative Surgery and Topographic Anatomy of the First Moscow State Medical University named after I.M. Sechenov we carried out anatomical study on cadavers (men and women, n=30).The study revealed topographical features of the lingual nerve and its relationship to other anatomical structures in the maxillolingual groove. It was found out that at the level of the second molar (96%) lingual nerve "crosses" duct of submandibular salivary gland, at the level of the third molar lingual nerve is located under the duct and lateral to it, closer to the inner surface of the body of the mandible. At the level of the first molar lingual nerve is located above and medial to Wharton duct and passes along sublingual-lingual muscles (m.hyoglossus).

[Upper airway stimulation in obstructive sleep apnea]. / Stellungnahme der Taskforce "Neurostimulation bei Schlafapnoe" zur Stimulation der oberen Atemwege.

The stimulation of the upper airway represents an effective treatment option in case of CPAP failure in patients with moderate to severe obstructive sleep apnea. The stimulation with respiratory sensing (Inspire Medical Systems) has shown a high level of evidence in larger cohorts and longer follow-up studies. Whether the results of the stimulation without respiratory sensing (ImThera Medical) can be compared with the therapy with sensing, remains open up to now. Additional data are awaited after the planned phase III study THN#2. To optimize both procedure and to provide long term results, more studies are needed. The workgroup "sleep medicine" of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery supports theses activities with the help of the newly founded task force "Neurostimulation in Sleep Apnea".

Schwannoma derived from lingual nerve occurring in floor of mouth.

A schwannoma is a benign tumor composed of schwann cells which forms on the periphery of nerves. We report a case of a schwannoma derived from a lingual nerve occurring in the floor of the mouth. The patient was a 27-year-old woman who presented with the complaint of a swelling in the floor of the mouth. It is difficult to distinguish a swelling from a sublingual gland tumor, cyst, or malignant tumor by MRI alone. Therefore, a biopsy and cytological examination were performed one week prior to surgery to determine whether the growth represented a malignancy. The results revealed a class II growth which was suspected to be a schwannoma. Intraoperatively, it became clear that the tumor and lingual nerve were inseparable, making excision of the nerve unavoidable. On the other hand, there was a clear border between the tumor and the sublingual gland, so it was possible to preserve the sublingual gland. In the postoperative pathological diagnosis, a definitive diagnosis was difficult based solely on H-E staining. Therefore, immunohistochemical staining was performed, resulting in a diagnosis of schwannoma. Currently, the patient is still being followed up. The results of this case indicate that preoperative aspiration biopsy cytology is useful in deciding the operative method to be employed.

Course and distribution of the lingual nerve in the ventral tongue region: anatomical considerations for frenectomy.

The aim of this study was to elucidate the sublingual and intralingual courses of the lingual nerve (LN) in the ventral tongue region, providing a clinical guide for safe surgical procedures such as frenectomy. We evaluated 16 specimens (32 sides) by gross observation after detailed dissections, and a further 6 specimens were examined after Sihler staining. All specimens were harvested from embalmed Korean cadavers. We classified the innervation patterns of the LN into 5 types and confirmed the distribution of the LN in the tip of the tongue. The classification of the LN was made with reference to a line formed by the interlacing of the styloglossus and genioglossus muscles. Based on the course of LN and the presence of a tiny twig (twigs directly innervating the ventral mucosa of the tongue, TM) directly innervating the sublingual mucosa, the course of the LN was classified as being straight, curved, or vertical and with or without the TM. Straight, curved, and vertical courses without the TM were seen in 9.4%, 46.9%, and 18.8% of the cases, respectively. Straight and curved courses with the TM were observed in 6.3% and 18.8% of the cases, respectively. Sihler staining revealed that the tongue tip is innervated by the LN. These findings indicate that surgical manipulations at the ventral tongue region might damage the LN and result in numbness of the tongue tip, and provide a useful anatomic reference for various surgical procedures involving the ventral tongue region.

Quantitative contributions of the muscles of the tongue, floor-of-mouth, jaw, and velum to tongue-to-palate pressure generation.

PURPOSE: The purpose of this investigation was to evaluate the relationship between tongue-to-palate pressure and the electromyography (EMG) measured from the mylohyoid, anterior belly of the digastric, geniohyoid, medial pterygoid, velum, genioglossus, and intrinsic tongue muscles. Methods Seven healthy adults performed tongue-to-palate pressure tasks at known percentages of their maximum pressure while intramuscular EMG was recorded from the muscles stated above. Multiple regression analysis was performed. RESULTS: Predictors of pressure included the posterior fibers of the genioglossus, mylohyoid, anterior belly of digastric, medial pterygoid, and intrinsic tongue. CONCLUSIONS: Increasing tongue-to-palate pressure coincides with increased muscle activity. Activation of the floor-of-mouth, tongue, and jaw closing muscles increased tongue-to-palate pressure. These findings support the use of a tongue-press exercise to strengthen floor-of-mouth muscles, tongue, and jaw-closing muscles.

Surgical release of a stone from the hilum of the submandibular gland: a technique note.

A minimally invasive surgical technique using an intra-oral approach for release of salivary stones from the proximal submandibular duct and hilum is described in detail. The different surgical steps are illustrated.

Endoscopic excision of the submandibular gland by an intraoral approach.

The recent advent of endoscopic procedures has compelled both plastic and neck and head surgeons to reconsider the conventional methods by which the excision of submandibular gland is classically achieved. An endoscopic intraoral approach for excision of the submandibular gland is described. This procedure is anatomically safe and can be made with minimal morbidity; a transcervical incision is avoided. Both specific instruments and solid anatomical knowledge are necessary to perform a safe and efficient glandular endoscopic excision. The essential surgical steps are as follows: 1) Careful identification of the Wharton duct and lingual nerve; 2) Retraction of the mylohyoid muscle; 3) Protection of the sublingual gland and lingual nerve; 4) Extraoral manipulation of the submandibular gland obtaining intraoral protrusion; and 5) Careful dissection of the posterior third of gland, avoiding injury on the facial artery and vein. Two patients were operated on with this technique and were very pleased with their results. No complications were registered. With advanced endoscopic instruments, new surgical technique, and surgeon experience, endoscopic intraoral excision of the submandibular gland can be the method of choice in benign neoplasia, sialolith, sialoadenitis and plunging ranula.

The relationship of the lingual nerve to the mandibular third molar region: an anatomic study.

PURPOSE: This study evaluated the relationship of the mandibular third molar to the lingual nerve. MATERIALS AND METHODS: An anatomic dissection of the lingual nerve in the third molar region was done on 20 cadavers (40 sides). RESULTS: The position of the nerve on one side bore no statistical relationship to the position of the nerve on the opposite side. The position of the lingual nerve was variable in both the sagittal and coronal planes. In two specimens the nerve lay superior to the lingual plate and in another the superior surface of the nerve was level with the crest of the lingual plate. CONCLUSION: These findings have implications for the avoidance of lingual nerve damage during surgery in the third molar and retromolar region of the mandible.

Occurrence of the ventral component of the third branchial nerve as the supernumerary branch of the glossopharyngeal nerve.

The authors found supernumerary branches of the glossopharyngeal nerve in 7 out of 368 head sides (184 bodies) of Japanese individuals. The branches entered the submandibular triangle and connected with the superficial cervical ansa. Teasing revealed that the components of the glossopharyngeal nerve were distributed not only in the subcutaneous layer of the neck but also in the lower facial muscles such as the orbicularis oris. This suggests that the third branchial arch sometimes participates in the formation of the facial muscles which are usually composed of the ventral component of the second branchial arch. Therefore, this supernumerary branch of the glossopharyngeal nerve is probably the ventral component of the third branchial nerve, which is originally distributed in the ventral component of the third branchial arch and usually disappears during later development. The present findings will clearly show how the branchiogenous region is demarcated against the somatic body wall.

[Reinnervation of posterior cricoarytenoid muscle: a comparison of nerve implantation and neuromuscular pedicle transfer in an animal model].

Recently, methods of reinnervating posterior cricoarytenoid muscle (PCA) have been reported by many authors. This study was undertaken to compare direct implantation (NI) of a branch of the ansa cervicalis supplying the sternothyroid muscle with the transfer of a neuro-muscular pedicle of the ansa cervicalis innervating the sternothyroid muscle (NMP) in a denervated PCA dog model. Both were carried out immediately after denervation. The results showed that reinnervation with return of physiological function of PCA were got by both methods of nerve transfer. The NMP was apparently superior to the NI. The reason was that the NMP implanted more motor end-plates into the denervated PCA. So the NMP should be chosen first when possible. The NI is consistently effective when NMP is not available.

Reinnervated radial forearm free flaps in head and neck reconstruction.

The radial forearm flap has proved to be a reliable free flap for intraoral reconstruction after major head and neck ablative surgery for cancer. In contrast to the myocutaneous flap, it is thin and flexible, and as a result, it is better suited to conforming to the irregular surface which remains over an intact or restored mandible. A criticism of both techniques however, is that while the flap effectively fills the defect, it serves as an insensate reservoir in which food and saliva can collect. A modification of the reinnervated radial forearm free flap is presented, with discussion of its use in three patients, following extensive resection of the floor of the mouth and tongue.

[Anatomical study on the facial nerve innervating the floor of the mouth in chondrichthyes. Homology of the chorda tympani].

This paper deals with the results of the investigation of the facial nerves of chondrichthyes in order to consider the phylogenetic origin of the Chorda tympani in human. Six species of elasmobranchs (Chlamydoselachus anguineus, Cephaloscyllium umbratile, Squalus acanthias, Dasyatis akajei, Raja kwangtungensis and Mobura diabolus) were dissected under a stereoscopic microscope for this purpose, and the following results were obtained. Ramus palatinus and R. pre-spiracularis were observed as pre-trematic branches, while R. mandibularis externus, R. mandibularis internus and R. hyoideus originating from R. hyomandibularis were observed as post-trematicus of the facial proper in chondrichtyes. The rami intermedii indicated by Tanaka and Nakao (1979) were observed only in Dasyatis akajei. The R. hyomandibularis of Squalus acanthias had cutaneous branches, and the same branches were described in Chimaera by Takahashi and Kobayashi (1988). R. pre-spiracularis and R. mandibularis internus supply the floor of mouth in Squalus acanthias. As for the other chondrichthyes, R. mandibularis internus was only the one that could be found at the floor of mouth cavity under a stereoscopic microscope. From the observations described above and from previous studies, it may be concluded that the problem of whether the Chorda tympani is homologous with whether the pre- or post-trematicus of branchial nerves seems to depend on the animal species.

Anatomical observations on the smaller sublingual nerves.

The nervous sublingual plexus was studied in 25 cadavers. One to 13 smaller sublingual branches, which spread through the sublingual region formations, were observed. These branches derive from the lingual nerve before and after the sublingual nerve origin. The proximal branches establish wide intercommunications with the sublingual nerve and its branches by means of well-individualized communicating loops in the sublingual plexus set.

Clinical significance of supplementary innervation of the lower incisor teeth: a dissection study of the mylohyoid nerve.

In view of the relevance of the mylohyoid nerve to clinical difficulties in achieving deep analgesia of the lower incisors, a dissection study was undertaken. Dissection from twenty-six adult cadavers of both sexes were studied with the aid of a dissecting microscope. The following observations were made: (1) A supplementary branch of the mylohyoid nerve entered the mandible through accessory foramina in the lingual side of the mandibular symphysis in 50% of the cases. (2) It generally arose from the right side (76.9%) and entered the inferior retromental foramen (84.6%). (3) The mylohyoid nerve branch either ended directly in the incisor teeth and the gingiva or joined the ipsilateral or contralateral incisive nerve. In view of this information concerning the high incidence of possible involvement of the mylohyoid nerve in mandibular sensory innervation, it is advisable to block it whenever intervention in the lower incisors is indicated. Routine mylohyoid injection is recommended after mental nerve block. If the inferior alveolar nerve is chosen for anesthetic purposes, additional mylohyoid injection should be given only if pain persists. The mylohyoid injection should be given at the inferior retromental foramen on the median aspect of the inferior border of the mandible through extraoral approach.

A rare local anesthetic misadventure. Case report and anatomic considerations.

When the mouth is fully opened, the depth to which the needle is inserted need not be great in order to pass through the submandibular gland capsule, and insertion of the needle behind the second molar tooth would result in passage behind the posterior border of the my-ohyoid muscle. The discussion indicates the relative ease with which fluid may penetrate the parapharyngeal space, particularly if pressure is used in injecting. Fluid diffusing into the region of the carotid triangle may have been responsible for the various symptoms, and anesthesia of the hypoglossal nerve, nerve, thyrohyoid nerve, internal and external laryngeal nerves, and carotid body possibly occurred. Anesthesia of the vagus is a remote possibility.