First-Bite Syndrome After Parapharyngeal Surgery for Cervical Schwannoma
Louis Mandel, DDS and
Steven B. Syrop, DDS
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ABSTRACT
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Background. First-bite syndrome (FBS) is a rare complication that occurs after patients undergo parapharyngeal space surgery. Characteristically, inadvertent ablation of the parotid gland’s sympathetic innervation results in the development of severe parotid gland–area pain at the first bite of food.
Case Description. The authors evaluated a patient who underwent parapharyngeal surgery for cervical schwannoma. This surgery involved the sympathetic chain’s superior cervical ganglion (SCG). With destruction of the SCG, the patient developed FBS and Horner syndrome.
Conclusion and Clinical Implications. Destruction of the SCG or the sympathetic postganglionic supply to the parotid gland causes severe parotid pain when food is first introduced into the mouth. The absence of discomfort during mechanical joint movements helps dentists differentiate this pain from myofascial pain or pain caused by temporomandibular dysfunction. The frequent presence of Horner syndrome also facilitates diagnosis.
Key Words: First-bite syndrome; Horner syndrome; superior cervical ganglion; sympathetic chainAbbreviations: FBS: First-bite syndrome • HS: Horner syndrome • PPS: Parapharyngeal space • SCG: Superior cervical ganglion
First-bite syndrome (FBS) has been recognized medically, but no reports concerning it are available in the dental literature. Netterville and colleagues1–3 defined FBS as originating from a postoperative complication after parapharyngeal space (PPS) surgery that ablates the sympathetic innervation to the parotid gland. Severe ipsilateral pain develops when patients first introduce food into their mouths,1–7 and it radiates from the upper neck to the parotid gland and auricular regions. The pain lasts approximately five seconds; gradually, but not totally, subsides with continued mastication; and then disappears within an hour. It returns with the next meal’s first bite. Sialagogues such as citric fruits intensify the pain. Some gradual resolution of the intensity and frequency of pain occurs across time.6 FBS can be differentiated from temporomandibular pain if mechanical joint movements do not elicit pain.
The PPS harbors 0.5 percent of all head and neck tumors; 70 to 80 percent of these tumors are benign.8 Surgical intervention usually is precipitated by the presence of a schwannoma, paraganglioma or parotid gland deep-lobe neoplasm.7 A schwannoma is a benign nerve-sheath tumor that can arise from cranial, peripheral or autonomic nerves, and as many as 50 percent occur in the head and neck area.6–9 Schwannomas represent 18 percent of the tumors that arise in the PPS, usually in patients who are 30 to 70 years of age.8 Most schwannomas in this area develop from the vagus nerve or the cervical sympathetic chain’s superior cervical ganglion (SCG) and its postganglionic fibers.8 However, schwannomas that involve the sympathetic chain rarely occur.6,9
With surgical involvement of the SCG, its postganglionic fibers or both, FBS can be anticipated. FBS may be complicated by the onset of Horner syndrome (HS). Loss of sympathetic innervation to the eyelids’ Müller muscle, the iris and facial sweat glands on the side of the head in which surgery occurred leads to eyelid ptosis, miosis and facial anhidrosis, respectively. This symptom complex is the classic diagnostic finding in HS.
We present a case report of a patient who was treated for a schwannoma of the cervical sympathetic chain. After surgery was performed, the patient developed both FBS and HS.
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CASE REPORT
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A 48-year-old woman who was in good health visited her internist for a routine medical examination in July 2007. During the examination, cervical palpation revealed a firm, painless, somewhat mobile nodule in the left parapharyngeal area. The nodule was situated along the anterior border of the sternocleidomastoid muscle at the same level as the second and third cervical vertebrae. Although the patient was unaware of the mass, she indicated when she was asked that she had vague symptoms of a lump in her throat that was most noticeable when she swallowed.
The patient underwent computed tomography with contrast material (Figure 1
) and received a tentative diagnosis of either a schwannoma or carotid-body tumor. Surgery was performed in November 2007. The surgeon discovered a benign tumor intimately involved with the SCG of the sympathetic chain. Histologically, the tumor was a schwannoma. After surgery, the patient experienced left eyelid ptosis and miosis (Figure 2), and she reported having "excruciating" parotid gland–area pain whenever food was first introduced into her mouth.
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Figure 1. Computed tomographic scan (axial view after administration of contrast material) showed a benign mass (arrows).
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Figure 2. Left eyelid ptosis and left miosis, which are characteristic of Horner syndrome, are evident.
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The patient received a diagnosis of HS, but the etiology of the pain initially was puzzling to clinicians. They eliminated myofascial pain and temporomandibular pain as causal factors when it became evident that masticatory mechanical movements did not trigger the pain. Because the pain radiated to the region of the parotid gland, the patient was referred to the Salivary Gland Center at Columbia University College of Dental Medicine, New York City, in January 2008.
Extraorally, we noted a normally healing cervical surgical site (Figure 3) along with left eyelid ptosis and miosis. The left parotid gland was not visibly swollen, and palpation indicated that it was painless and normal in tone. Orally, the mucosa was normally moist. All salivary ducts were patent, and we observed a normal clear flow from each duct orifice at massage of salivary gland.
Our investigation confirmed that the severe pain radiating to the parotid gland region originated when the patient first put food into her mouth. The pain lasted approximately five seconds and then partially subsided with subsequent bites of food. The pain was reproduced readily whenever she started a new meal. We added a diagnosis of FBS to the diagnosis of HS.
A variety of analgesics had been prescribed to the patient, and she experienced only limited pain reduction.
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DISCUSSION
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Netterville and colleagues1–3 suggested that FBS results from a loss of sympathetic innervation to the parotid gland. Anatomically, the sympathetic chain’s SCG is approximately 3 centimeters long and lies posterior to the carotid sheath at the level of the second and third cervical vertebrae. Postganglionic fibers from the SCG run along with the external carotid artery as a plexus to supply sympathetic innervation to the parotid gland and the face. Postganglionic fibers from the SCG also run as a nerve plexus along with the internal carotid artery to the eye and orbit.
Damage to the SCG or the plexus around the internal carotid artery can cause HS. Similarly, an injury to the SCG, damage to the plexus around the external carotid artery or both will lead to a loss of sympathetic innervation to the parotid gland. The sympathetic receptors on the surface of the myoepithelial cells that peripherally circumscribe salivary ducts will develop denervation supersensitivity.3–6 With salivary stimulation by food, there is a release of parotid gland parasympathetic neurotransmitters that cross over to stimulate the myoepithelial cell’s sympathetic receptors. The resulting increased response of these cells is thought to cause spasms with pain.3–6
Chiu and colleagues4 defined two varieties of symptoms that occur with surgical ablation of the SCG, its postganglionic fibers or both. HS will develop if there is disruption of the SCG or the postganglionic sympathetic plexus that runs with the internal carotid artery. The symptoms of FBS will develop when there is significant surgical damage to the SCG or to the postganglionic plexus that is associated with the external carotid artery, because this artery courses to the parotid gland. Some cases of PPS tumors require ligation of the external carotid artery but do not implicate the SCG. In such situations, the symptoms of FBS can be expected, but HS will not be present.
Kawashima and colleagues7 reviewed 22 cases of surgery for benign tumors in the PPS. Patients in nine of these cases developed FBS. Three of the nine patients with FBS had been treated for schwannomas and developed HS because their cervical sympathetic ganglions had been ablated. The remaining six patients had undergone deep-lobe parotidectomies for pleomorphic adenomas, and their SCGs had not been ablated. These six patients required external carotid artery ligation. Although these patients developed FBS, they did not develop HS; the sympathetic supply to their eyes from the SCG or from the plexus around the internal carotid artery was not involved.
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TREATMENT
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Treatment for FBS has not been highly successful. The administration of carbamazepine has not relieved the associated pain,3,4,7 nor has the administration of nonsteroidal anti-inflammatory agents been successful.4,7 Surgical resection of the parasympathetic innervation to the parotid gland, either by removal of the Jacobson plexus or the auriculotemporal nerve up to the foramen ovale, has not relieved the pain effectively.3,4 Dietary modification by means of consuming bland foods to avoid increased salivary stimulation has been advised.1 Because there is a tendency for the painful symptoms of FBS to subside with time, observation is always an option.1
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CONCLUSION
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FBS represents a rare and diagnostically puzzling condition. Because its primary manifestation, severe pain with the first bite of food, is associated with the anatomical location of the parotid salivary gland, patients often seek help from dental practitioners. The diagnostic key rests in the history of recent parapharyngeal surgery and dentists’ ability to differentiate the condition from temporomandibular dysfunction and myofascial pain. The frequent presence of HS facilitates diagnosis. Supportive palliation is all that can be offered to patients because no definitive therapy for FBS has been developed.
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FOOTNOTES
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Dr. Mandel is the director, Salivary Gland Center, College of Dental Medicine, Columbia University, New York City; and an assistant dean and clinical professor, Division of Oral and Maxillofacial Surgery, College of Dental Medicine, Columbia University, New York-Presbyterian Hospital, New York City. Address reprint requests to Dr. Mandel at Division of Oral and Maxillofacial Surgery, College of Dental Medicine, Columbia University, New York-Presbyterian Hospital, 630 W. 168th St., New York, N.Y.
Dr. Syrop is an associate clinical professor, Columbia University College of Dental Medicine, New York City.
Disclosure. None of the authors reported any disclosures.
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REFERENCES
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- Netterville JL, Civantos FJ. Rehabilitation of cranial nerve deficits after neurologic skull base surgery. Laryngoscope 1993;103(suppl 60):45–54.[Medline]
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- Netterville JL, Jackson CG, Miller FR, Wanamaker JR, Glasscock ME. Vagal paraganglioma: a review of 46 patients treated during a 20-year period. Arch Otolaryngol Head Neck Surg 1998;124(10): 1133–1140.[Abstract/Free Full Text]
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- Kamal A, Abd El-Fattah AM, Tawfik A, Razek AA. Cervical sympathetic schwannoma with postoperative first bite syndrome. Eur Arch Otorhinolaryngol 2007;264(9):1109–1111.[Medline]
- Kawashima Y, Sumit, Sugimoto T, Kashimoto S. First-bite syndrome; a review of 29 patients with parapharyngeal space tumor. Auris Nasus Larynx 2008;35(1):109–113.[Medline]
- Saito DM, Glastonbury CM, El-Sayed IH, Eisele DW. Parapharyngeal space schwannomas: preoperative imaging determination of the nerve of origin. Arch Otolaryngol Head Neck Surg 2007;133(7):662–667.[Abstract/Free Full Text]
- Kara CO, Topuz B. Horner’s syndrome after excision of cervical sympathetic chain schwannoma. Otolaryngol Head Neck Surg 2002;127(1):127–128.[Medline]
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