Surgical reneurotization of the tongue after unilateral paralysis of the hypoglossal nerve

Summary Hemiglossal paralysis due to lesions of the peripheral hypoglossal nerve leads to marked muscle atrophy with disturbed functioning in a minority of cases. Reinnervation from the unparalyzed, contralateral side may then be desired. In animal experiments on cats, a Z-plasty of the midportion of the tongue was carried out by transposing a portion of the normal tongue musculature into the opposite side following denervation 1 month previously by resection of the hypoglossal nerve. Electromyography was performed 13 months later. The tongue was then examined histochemically in serial sections in search of the motor endplates together with the nerves fibers. However, there was no evidence for reinnervation in the specimens examined. Signs of successful reanimation of the tongue by Z-plasty may be caused by mechanical synkinesia due to scar formation rather than by actual reneurotization.Excerpts presented at the 59th annual meeting of the German Society for Otorhinolaryngology — Head and Neck Surgery (Deutsche Gesellschaft für Hals-Nasen-Ohrenheilkunde, Kopf- und Halschirurgie), Nornberg, 15–19 May 1988     

Course of the hypoglossal nerve in tongue musculature]

BACKGROUND: The main trunk of the hypoglossal nerve enters the tongue body anterior to the hypoglossal muscle and runs in a medial direction. RESULTS: Close to the lingual septum, the nerve changes its direction to a superior path and in a second change to an anterior path. The terminal branches disperse in the apical part of the tongue. To avoid injury of the hypoglossal nerve during surgical procedures within the body of the tongue, two fingerbreadth areas should be preserved. The first area lies in a vertical direction, from the entry of the nerve up to the longitudinal superior and inferior muscles. The second area extends from here in an anterior direction up to the lingual apex.     

Morphological changes of the posterior airway space after tongue base suspension

OBJECTIVES/HYPOTHESIS: The objectives were 1) to demonstrate the efficacy of tongue base suspension with the Repose System in modifying the posterior airway space on the basis of morphological changes in the retrolingual space and 2) to determine the implications of this procedure for the treatment of obstructive sleep apnea syndrome on polysomnographic and psychometric data. STUDY DESIGN: A prospective, nonrandomized study. METHODS: Polysomnography was performed before as well as 3 and 12 months after surgery in patients undergoing tongue base suspension using the Repose System. To identify morphological changes in the posterior airway space, lateral cephalometric radiography and videoendoscopy of the pharynx were performed preoperatively and postoperatively. Twenty-eight male patients with obstructive sleep apnea syndrome were included in the study. A suspension suture anchored intraorally at the mandible was passed submucosally in the body of the tongue, with suture tightness adjusted individually. RESULTS: The posterior airway space was widened by at least 2 mm in 60% of cases. Daytime sleepiness improved subjectively in 67% of patients, and the respiratory disturbance index improved postoperatively in 55%. The correlation between posterior airway space widening and the improvements in daytime sleepiness and respiratory disturbance index was not significant. CONCLUSION: Surgical intervention in obstructive sleep apnea syndrome with the Repose System does not result in permanent anatomical change in the posterior airway space.     

舌动脉和舌下神经的解剖特点及与舌根的解剖关系

目的:观察舌动脉、舌下神经的走行及其与舌表面标志点的关系,以及舌动脉、舌下神经的相互关 系,为临床提供舌动脉、舌下神经的形态学资料,指导舌根手术,提高手术安全性。方法:10具(20侧)甲醛固定、 颌面部发育正常的成人尸头标本,颈总动脉灌注红色乳胶。观察:①舌动脉和舌下神经的起源、走行、分段,测量 各段长度;②舌动脉和舌下神经与各解剖标志点的距离;③舌动脉和舌下神经的解剖关系。结果:舌动脉全长为 (9.73±0.83)cm;第1、2、3、4段分别为(1.81±0.46)cm、(2.98±0.45)cm、(1.24±0.39)cm、(3.79±0.28)cm。 舌动脉主干距舌盲孔前1cm、舌盲孔、舌盲孔后1cm及舌盲孔至舌骨、舌侧缘,舌动脉距舌侧缘的距离分别为 (2.34±0.20)cm、(2.48±0.14)cm、(2.43±0.26)cm、(2.53±0.33)cm、(2.14±0.16)cm、(1.11±0.09)cm。舌 下神经距舌盲孔前1cm、舌盲孔、舌盲孔后1cm、舌骨、舌侧缘及下颌骨内侧缘的距离分别为:(2.28±0.14)cm、 (2.36±0.18)cm、(2.34±0.21)cm、(1.25±0.42)cm、(1.86±0.32)cm、(2.64±0.28)cm。舌下神经与舌动脉最 小距离、舌下神经在舌骨大角距舌动脉距离、舌下神经与舌动脉交叉点距舌骨的垂直距离分别为: (0.38±0.38)cm、(0.35±0.31)cm、(1.48±0.26)c     

舌动脉及舌下神经与舌根的解剖关系

目的 通过舌重要神经血管局部解剖学特点的研究,探讨舌等离子射频消融术进针的安全范围.方法 对8例(16侧)成人尸体舌的局部解剖测量,了解舌动脉及舌下神经在舌内的走行,并进行相对定位.结果 舌动脉及舌下神经的主干在舌盲孔周围距舌表面的垂直距离不随其走行而改变,约为20 mm;但其水平位距中线距离差异有统计学意义(P<0.01),越靠近舌前部距离越小.舌动脉水平位距中线距离与舌宽的比值于舌盲孔后10mm、舌盲孔及舌盲孔前10mm分别为0.269±0.012、0.262±0.003及0.233±0.009,舌下神经水平位距中线距离与舌宽的比值在以上3个断面分别为0.262±0.010、O.202±0.014及0.193±0.010,即舌动脉及舌下神经主干在舌根部走行于舌中线与舌外缘连线的内1/3与外1/3之间,靠近舌外缘侧1/3处.结论 舌根等离子射频消融的相对安全范围:舌表面下垂直深度不超过20mm,水平方向为舌中线与舌外缘连线的内1/3和外1/3,舌中线与舌外缘连线的外1/3处是最危险的部位.     

Anatomy of the hypoglossal nerve and the hypoglossal ansa cervicalis

The hypoglossal nerve is the motor nerve of the tongue and the ansa cervicalis is a motor nerve for the sub-hyoid muscles. The hypoglossal nerve seems to give the innervation of the thyrohyoid although it is a sub-hyoid muscle. Most of axons in the ansa cervicalis arise from the three first cervical nerves. These nerves are in close contact because of the cervical ontogeny of the tongue and the hypoglossal nerve. Nerve impulse in the superior root of the ansa cervicalis runs caudally to rostrally. This is why neurotization techniques using the superior root of the ansa cervicalis produce poor results in the treatment of facial palsy sequelae.     

Role of the trigeminal nerve in regrowth of hypoglossal motoneurons after hypoglossal-facial anastomosis

Conclusion. Functional recovery of facial muscles following hypoglossal-facial anastomosis (HFA) may be dependent not only on sensory information, relayed via the trigeminal nuclei to the hypoglossal nucleus, but also on extratrigeminal fibers, originating from the hypoglossal nucleus that travel in the infraorbital nerve (ION). This fact helps to explain the ability of hypoglossal neurons, after HFA, to induce contractions of muscles originally innervated from other nervous structures. Objective. The aim of the study was to better understand the role of the trigeminal nerve in reinnervation of facial muscles by hypoglossal motoneurons following HFA. Materials and methods. Central afferences of the ION were analyzed in rats by labeling the exposed nerve with horseradish peroxidase (HRP), whereas central organization of the efferent projections to the vibrissal area was analyzed by labeling the whisker pad muscles of the rat with a 5% solution of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (Dil) in N,N-dimethylformamide. Results. The results show that extratrigeminal fibers, originating in the hypoglossal nucleus, travel along the ION. Retrograde tracing applied to ION or injected into the whisker pad showed labeled neurons in the Pr5 nucleus and all Sp5 trigeminal subnuclei. Small labeled neurons (10-15 microm diameter; 10-12 neurons per section), were also found in the hypoglossal nucleus.     

Neurotization of pectoralis major myocutaneous flap by the hypoglossal nerve in tongue reconstruction: clinical and experimental observations

Recently, neurotization has been proposed for providing mobility to the pectoralis major, or other myocutaneous flap in lingual reconstruction following total glossectomy. The development of an active tongue-like structure may offer the patient higher potential for rehabilitation of speech and deglutition. The purpose of this thesis is to report experimental and clinical observations on neurotization of the pectoralis major myocutaneous flap. The pectoralis major myoflap of 16 rats was reinnervated by either a hypoglossal nerve pedicle of hypoglossal-genioglossus muscle neuromuscular pedicle. Functional flap reinnervation was confirmed in eight of the 16 animals. The author's clinical experience with reconstruction of the tongue utilizing neurotized pectoralis major myocutaneous flap is presented.     

Role of the trigeminal nerve in regrowth of hypoglossal motoneurons after hypoglossal-facial anastomosis

Conclusion. Functional recovery of facial muscles following hypoglossal-facial anastomosis (HFA) may be dependent not only on sensory information, relayed via the trigeminal nuclei to the hypoglossal nucleus, but also on extratrigeminal fibers, originating from the hypoglossal nucleus that travel in the infraorbital nerve (ION). This fact helps to explain the ability of hypoglossal neurons, after HFA, to induce contractions of muscles originally innervated from other nervous structures. Objective. The aim of the study was to better understand the role of the trigeminal nerve in reinnervation of facial muscles by hypoglossal motoneurons following HFA. Materials and methods. Central afferences of the ION were analyzed in rats by labeling the exposed nerve with horseradish peroxidase (HRP), whereas central organization of the efferent projections to the vibrissal area was analyzed by labeling the whisker pad muscles of the rat with a 5% solution of 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (Dil) in N,N-dimethylformamide. Results. The results show that extratrigeminal fibers, originating in the hypoglossal nucleus, travel along the ION. Retrograde tracing applied to ION or injected into the whisker pad showed labeled neurons in the Pr5 nucleus and all Sp5 trigeminal subnuclei. Small labeled neurons (10–15 µm diameter; 10–12 neurons per section), were also found in the hypoglossal nucleus.     

Parapharyngeal neurilemmoma of the hypoglossal nerve

Although neurilemmomas are uncommon cervical neoplasms, they account for a significant percentage of parapharyngeal space tumors. These neoplasms may originate from any nerve traversing · this space, but the vast majority arise from the vagus nerve and sympathetic chain. Satisfactory treatment of neurilemmomas consists of total excision which is best accomplished via an external approach. Immediate nerve grafting is advocated when a segment of cranial nerve must be sacrificed in order to achieve complete tumor removal. A case of a parapharyngeal neurilemmoma arising from the hypoglossal which required treatment in this manner is presented. Electromyographic studies performed 15 months postoperatively demonstrate reinervation of the lingual musculature via the nerve graft.     

Peripheral neurinoma of the hypoglossal nerve

Neurinomas of the hypoglossal nerve are rarely reported. In most cases these tumors are intracranial or sited at the skull base. Only a few solitary neurinomas of the twelfth cranial nerve have been reported. In most of these cases the tumors arose from the descending part of the nerve in the parapharyngeal space. We report the first neurinoma recorded arising from the submandibular course of the hypoglossal nerve.