Duplicate Omohyoid Muscle Causing Progressive Dysphagia and Dyspnea

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CLINICAL MEDICINE Duplicate Omohyoid Muscle Causing Progressive Dysphagia and Dyspnea: A Case Report Rijul Kshirsagar, MD1; Jason Gilde, MD1; Raul Cruz, MD1 Perm J 2019;23:18.316 E-pub: 09/12/2019 https://doi.org/10.7812/TPP/18.316

ABSTRACT specifically laryngeal-hyoid complex tor- Introduction: Duplicate omohyoid sion with limited neck motion, followed muscles are uncommon anomalies and by progressive dysphagia and dyspnea. exceedingly rare causes of progressive The study is a retrospective medical record clinical symptoms. The goals of this case review, including clinical evaluation, imag- report are to describe the clinical charac- ing studies, and preoperative, intraopera- teristics, cross-sectional imaging, intraop- tive, and postoperative photographs. The erative findings, and curative treatment goals of the present study are to describe of our patient, to develop a differential the clinical characteristics, cross-sectional diagnosis for this condition, and to review Figure 1A. Preoperative patient photograph reveal- imaging, intraoperative findings, and cura- ing a prominent right-rotated, inferiorly displaced the pertinent literature regarding this tive treatment for our patient, to develop larynx (arrow) caused by a palpable tense tissue particular type of anomalous omohyoid a differential diagnosis, and to describe band from the right hyoid to the ipsilateral clavicle. Figure 1B. Postoperative photograph revealing muscle as one among many variations. pertinent variations in the anomalous Case Presentation: A 20 year-old man neck scar and resolution of distorted central neck omohyoid muscle based on the published anatomy. presented with progressive limited neck literature. range of motion followed by dysphagia This article was originally presented and then dyspnea caused by his dupli- as a poster at the American Academy of cate omohyoid muscle. He underwent Otolaryngology—Head and Neck Surgery curative surgery in 2015 at our tertiary Annual Meeting; September 18, 2016 to care center. September 21, 2016; San Diego, CA. Discussion: Although rare, a duplicate omohyoid muscle should be con- CASE PRESENTATION sidered in the differential diagnosis of Presenting Concerns dysphagia and dyspnea with concurrent A 20-year-old man first presented to central neck deformity. We report the first our institution for evaluation of progres- case, to our knowledge, of an anomalous sive neck distortion, limited range of omohyoid that caused significant pro- motion in the left side of the neck, and gressive clinical symptoms. Direct exci- positional dysphagia. The patient was born sion of the restrictive anomalous tissue via a normal atraumatic vaginal delivery proved curative. and had no early torticollis. His clinical examination revealed neck distortion with Figure 2. Preoperative endoscopy revealing right- INTRODUCTION prominent right-sided laryngeal complex ward deviation of the larynx. Note the patent airway with a prominent anterior subglottic shelf (asterisk) Anatomic variations of the omohyoid rotation and inferior displacement. A tense caused by the impinging cricoid cartilage. muscle occur with relatively high fre- subcutaneous band could be palpated in quency likely because of the complicated the right side of the neck between the embryologic and anatomic features. The hyoid and clavicle, which was especially omohyoid is an infrahyoid strap muscle pronounced with left-sided head rotation. After reviewing the results, we suspected that consists of a superior and inferior Results of a modified barium swallow the patient to have a muscular anomaly, belly separated by an intermediate ten- study revealed normal swallowing without and surgery was planned for exploration don. The muscle originates from the up- aspiration. Physical therapy yielded no and possible excision of abnormal tissue. per border of the scapula and inserts at benefit. He declined steroid injection and the lower border of the body of the hyoid opted for observation. bone. Numerous anomalous variations of At 23 years of age, he was reevaluated the omohyoid have been previously de- after developing mild dyspnea. Subsequent Author Affiliations scribed. However, few of these deformities physical examination (Figures 1A and 1B), 1 Department of Head and Neck Surgery, Oakland Medical Center, CA cause clinical symptoms. We report the distal chip camera laryngoscopy (Figure 2), first case, to our knowledge, of a dupli- and magnetic resonance imaging of the Corresponding Author Rijul Kshirsagar, MD ([email protected]) cate omohyoid-causing neck deformity, neck (Figures 3A and 3B) were performed. Keywords: anomalous omohyoid, duplicate omohyoid, dysphagia, neck dissection

The Permanente Journal • https://doi.org/10.7812/TPP/18.316 The Permanente Journal • For personal use only. No other uses without permission. Copyright © 2019 The Permanente Press. All rights reserved.1 CLINICAL MEDICINE Duplicate Omohyoid Muscle Causing Progressive Dysphagia and Dyspnea: A Case Report

Therapeutic Intervention and Treatment Multiple omohyoid anomalies are de- Despite a preoperative endoscopy scribed according to the origin, insertion, that revealed a rotated but patent, unob- course, number of bellies, and contribution

structed airway, intubation of the patient of surrounding muscles. In fact, in 1931, 5 proved difficult. Even with an easily vis- Loth attempted to develop a classification ible laryngeal introitus, the endotracheal scheme for the various subtypes. However, tube would not pass the subglottic level exceptions to his classification scheme 4 on 2 routine intubation attempts. With have subsequently been identified. In the video laryngoscope used for visualization, more recent 2008 anatomical study by Rai 2 a tube-changer stylet was passed beyond et al, among the 35 cadavers dissected, a the subglottis after several attempts, and double omohyoid was present in 1 cadaver, the patient was intubated by sliding the the inferior belly originated from the clavi- endotracheal tube over the stylet (modi- cle in 3 cadavers, the superior belly merged fied Seldinger technique). We retrospec- with the sternohyoid in 2 cadavers, and tively hypothesized that the endotracheal the omohyoid received additional muscle tube was lodging in the prominent an- fibers from the sternum in 1 cadaver. terior cricoid shelf. This hypothesis was Standard attachments and position of the confirmed on preoperative endoscopy omohyoid were observed in the remaining

and revealed to be caused by laryngeal 28 cadavers (85%). Indeed, the number of distortion associated with this deformity. variations in the development and position During the procedure, after the sub- of the muscle have caused the muscle to platysmal flaps were raised, a normal- be questioned as a reliable surgical land- 6 appearing lateral omohyoid and an mark. Mizen and Mitchell attempted to accompanying medial duplicate omohy- define the reproducibility of the position oid muscle were identified (Figures 4A of the omohyoid muscle through a study and 4B). The duplicate omohyoid muscle Figure 3A. Coronal magnetic resonance of 30 cadavers and 88 patients undergoing imaging showing fibrosis (arrow) causing inferior at the hyoid bone was divided, resulting in displacement of larynx. neck dissections and found the position an immediate 3-cm shift of the laryngeal- Figure 3B. Axial magnetic resonance imaging of the omohyoid muscle in relation to the hyoid complex back toward the midline showing rightward horizontal rotation of the larynx. clavicle and internal jugular vein to vary (Figure 4C). The normal-appearing considerably. The authors suggest that the omohyoid muscle was also divided at its omohyoid is an unreliable surgical land- hyoid attachment at this time. Pathologic Thus, although abnormalities of the mark during neck dissection and its use analysis of the duplicate omohyoid re- omohyoid muscle are rarely encountered should be abandoned. vealed fibrous tissue and skeletal muscle. in clinical practice, they may occur rela- Descriptions of a duplicated omohyoid tively commonly because of the complex muscle are exceedingly rare. We found Follow-up and Outcome embryologic and anatomical structure of 4 cadaveric and 1 incidental description At 4 weeks after surgery, external this muscle. during a neck dissection of this duplicate (Figure 1B) and endoscopic examination revealed an improved appearance in the patient. At final follow-up 6 weeks after Table 1. Timeline of the case surgery, the patient reported complete Date Summaries from initial and follow-up visits resolution of his symptoms. 12/20/12 Initial presentation to Head and Neck Surgery at age 20 found the patient to have distorted DISCUSSION neck anatomy and dysphagia. An MRI scan was ordered. 11/4/14 The patient re-presented with increasing dysphagia. He had some difficulty breathing.The Although many muscles of the neck patient was offered neck exploration with possible lysis of scar or muscle band. develop embryologically from the bran- 6/12/15 The patient was interested in pursuing surgery, which was planned for October 2015. He chial arch mesenchyme, the infrahyoid underwent preoperative laryngoscopy as well as repeat MRI. muscles form from myoblasts from the 10/26/15 The patient underwent transcervical excision of duplicate omohyoid muscle in the cervical myotomes.1 Omohyoid anomalies operating room. have been suggested to occur because of 11/3/15 At the first postoperative visit, the patient’s swallowing function had improved. There was pertubations in this development process.2 some expected neck pain. In addition, it has long been proposed that 12/3/15 At the second postoperative appointment, there was no further difficulty with swallowing; the superior and inferior bellies of the the neck incision was well healed. Laryngoscopy was performed and was normal. omohyoid develop from different muscle 12/1/18 Per a phone call with the patient, there were no symptoms of dysphagia. Appearance of precursors.3 Superior muscle belly abnor- the neck was normal to the patient. malities are more commonly reported.4 MRI = magnetic resonance imaging.

The2 Permanente Journal • For personal use only. No other uses without permission. Copyright © 2019 The Permanente Press. All rights reserved. The Permanente Journal • https://doi.org/10.7812/TPP/18.316 CLINICAL MEDICINE Duplicate Omohyoid Muscle Causing Progressive Dysphagia and Dyspnea: A Case Report

Disclosure Statement The author(s) have no conflicts of interest to disclose.

Acknowledgements Laura King, ELS, performed a primary copy edit.

How to Cite this Article Kshirsagar R, Gilde J, Cruz R. Duplicate omohyoid muscle causing progressive dysphagia and dyspnea: A case report. Perm J 2019;23:18.316. DOI: https://doi.org/10.7812/TPP/18.316

Figure 4A. Intraoperative photograph Figure 4B. The isolated Figure 4C. Lysis of the showing the normal, more lateral duplicate muscle spanning abnormal muscle results in an References omohyoid muscle (arrow) parallel to the from the clavicle to the tilted immediate 3-cm separation of 1. Rai R, Nayak SR, Ranade AV, Prabhu LV, more medial, tense duplicate omohyoid hyoid and displacing the the muscle ends (asterisks) Vadgaonkar R. Duplicated omohyoid muscle and its clinical significance. Rom J Morphol Embryol muscle (asterisk). larynx. and improvement of the 2007;48(3):295-7. DOI: https://doi.org/10.1590/ distorted laryngeal anatomy. s1807-59322008000400018. 2. Rai R, Ranade A, Nayak S, Vadgaonkar R, Mangala P, Krishnamurthy A. A study of anatomical muscle. None of these presented with form of autoimmune thyroiditis unilat- variability of the omohyoid muscle and its 1,7-10 clinical relevance. Clinics (Sao Paulo) 2008 clinical symptoms. Two of the re- erally could also present in this manner. Aug;63(4):521-4. DOI: https://doi.org/10.1590/s1807- 9,10 ports described a duplicate muscle However, the patient’s lesion never showed 59322008000400018. that exactly matched our intraoperative evidence of an acute inflammatory stage. 3. Anderson RJ. The morphology of the omohyoid muscle. Dublin J Med Sci 1881;10:1-17. findings (ie, a cleidohyoideus muscle be- We report the first case, to our knowl- 4. Noussios G. Omohyoid muscle’s interesting tween the hyoid and clavicle without an edge, of an anomalous omohyoid that anatomical variations: Review of the literature. intermediate tendon running medial and caused significantly progressive clinical Internet J Hum Anatomy. 2015;3(1). DOI: https://doi. org/10.5580/IJHA.24221. separate from a normal omohyoid muscle). symptoms and difficult intubation. In 5. Loth E. Anthropologie des parties Molles. Paris, Cadaveric studies or reports based on our case, direct excision and release of the France: Werner Wachsmuth;1931. incidental findings during neck surgery anomalous tissue via an open surgical ap- 6. Mizen KD, Mitchell DA. Anatomical variability of 14 omohyoid and its relevance in oropharyngeal cancer. comprise the largest volume of reports of proach were curative. Zhu et al describe Br J Oral Maxillofac Surg 2005 Aug;43(4):285-8. DOI: omohyoid anomalies, certainly suggesting the use of an endoscope via a transaxillary https://doi.org/10.1016/j.bjoms.2004.11.019. that clinically symptomatic variations are approach for simple surgical transection 7. Miura M, Kato S, Itonaga I, Usui T. The double omohyoid muscle in humans: Report of one case exceptional. In fact, reports of anoma- of the omohyoid muscle in a patient with and review of the literature. Okajimas Folia Anat Jpn lous omohyoid varieties causing clinical omohyoid muscle syndrome. In both of 1995 Aug;72(2-3):81-97. DOI: https://doi.org/10.2535/ symptoms are rare. Several studies11,12 have these cases, the variant muscle required ofaj1936.72.2-3_81. 8. Kim DI, Kim HJ, Park JY, Lee KS. Variation of described omohyoid muscle syndrome, surgical treatment and failed nonsurgi- the infrahyoid muscle: Duplicated omohyoid and also known as omohyoid sling syndrome, cal options. appearance of the levator glandulae thyroideae in which the omohyoid causes protrusion muscles. Yonsei Med J 2010 Nov;51(6):984-6. DOI: https://doi.org/10.3349/ymj.2010.51.6.984. of the lower neck during swallowing. In CONCLUSION 13 9. Hatipoğlu ES, Kervancioğlu P, Tuncer MC. An a separate case report, fibrosis of the The omohyoid muscle may demonstrate unusual variation of the omohyoid muscle and review omohyoid was described as the cause of a variety of anomalies. THe muscle may of literature. Ann Anat 2006 Sep;188(5):469-72. DOI: https://doi.org/10.1016/j.aanat.2006.03.004. dysphagia and acquired torticollis. rarely be duplicated. The exact frequency 10. Fukuda H, Onizawa K, Hagiwara T, Iwama H. The differential diagnosis for this type of omohyoid variations is unknown, but The omohyoid muscle: A variation seen in radical of lesion is relatively limited. Torticollis these variations perhaps are more com- neck dissection. Br J Oral Maxillofac Surg 1998 Oct;36(5):399-400. DOI: https://doi.org/10.1016/ typically involves the sternocleidomastoid mon than reported because of the complex s0266-4356(98)90668-4. muscle and may be associated with deliv- embryologic and anatomic features of the 11. Wong DS, Li JH. The omohyoid sling syndrome. ery trauma (and thus is evident early in muscle. However, few of these anomalies Am J Otolaryngol 2000 Sep-Oct;21(5):318-22. DOI: https://doi.org/10.1053/ajot.2000.16161. life). THe area of neck fibrosis is recogniz- will present clinically. Ours is an extremely 12. Kim L, Kwon H, Pyun SB. Pseudodysphagia due ably different from our case. Other central rare and interesting case of a duplicate to omohyoid muscle syndrome. Dysphagia. 2009 neck pathologic findings that could occur omohyoid that caused progressive symp- Sep;24(3):357-61. DOI: https://doi.org/10.1007/ s00455-008-9206-8. would typically have an inflammatory toms, produced a challenging intubation, 13. Bond JM, Murrell ZC, Foley DS. Acquired torticollis component that contributes to scar band and was cured through surgical excision. secondary to omohyoid muscle fibrosis. J Pediatr formation. For example, a recurrently or Omohyoid muscle anatomy should be re- Surg Case Rep 2014 Aug;2(8):397-9. DOI: https:// doi.org/10.1016/j.epsc.2014.08.003. chronically infected thyroglossal duct cyst, lied on cautiously during neck dissection, 14. Zhu B, Li K, Li D, et al. Endoscopic surgery for laryngocele, sclerosing cervical lymphade- and anomalies should be considered in omohyoid muscle syndrome. J Laparoendosc Adv nopathy, or upper-pole inflamed thyroid the differential diagnosis of symptomatic Surg Tech A 2015 Aug;25(8):672-4. DOI: https://doi. v org/10.1089/lap.2015.0194. neoplasm might present similarly. A central neck deformities.