TMJ Disorder Mimic Ernest Syndrome Diagnosis and Treatment
Orofacial pain is a term commonly used to describe pain involving the hard and soft structures of the face, head, oral cavity and neck.1 Ernest Syndrome, one of several orofacial disorders, is often mistaken for temporomandibular disorder (TMD), which is itself a type of orofacial dysfunction that comprises a number of symptoms involving the TM joints, the muscles of mastication and related structures and is often accompanied by TM joint noises, restrictions in opening, lateral jaw deflection to the affected side and impaired functional ability.
Ernest Syndrome, on the other hand, involves the stylomandibular ligament (SML) and its insertion on the posterio-medial aspect of the mandible. The origin of the SML is the styloid process, a bony protuberance that is attached to the temporal bone, just anterior to stylomastoid foramen and extends inferiorly in an antero-medial direction (see Figure 1).1,2 The SML insertion is on the posterio-medial border of the mandibular approximately 10 mm to 15 mm superior to the gonial angle.3,4
The symptoms of Ernest syndrome are temporal headache pain, eye pain, pain in the mandible itself, pain in and around the TM joint, ear pain and fullness, odontalgia, throat pain and pain in other orofacial areas.5 Two different stages of this disorder have been identified by Dr. Ernest. The initial stage has tenderness below the ear and in the posterior mandible near the gonial angle. In the later stages, subjects may have pain in the TMJ, eye and the area behind the eye — possibly with vision changes, mandible, throat, zygomatic arch and coronoid process, temporal region and mandible posterior teeth. Ear symptoms such as pain, fullness and stuffiness are frequently seen along with TMJ clicking or locking, and restricted jaw ranges of motion. Neck and shoulder complaints also occur occasionally.6 These symptoms are similar to the symptoms of internal derangement of the TM joint, temporal tendinitis, and occipital neuralgia, which this disorder can mimic (see Table 1). 5,7
Ernest syndrome is best diagnosed utilizing the patient’s history, site palpation, and successful application of an anesthetic block of the SML insertion. The subject must have a positive history of pain in a known referral area. This pain must be present at the SML mandibular attachment, and most importantly, the subject’s pain must be reduced with a local anesthetic injection into the SML insertion. Bell and Mahan recommend diagnostic anesthetic blocks to differentiate pain syndromes.8,9
The injury site is located by palpating 10mm to 15mm superio-medially from the mandibular angle on the painful side. The SML’s insertion is in close proximity to the parotid gland, the posterior belly of the digastric and the medial pterygoid muscle. While the above structures and the transverse process of the atlas are in the area of the SML and are sensitive to firm palpation, a symptomatic SML is very sensitive and on the medial aspect of the mandible. A comparison of Ernest Syndrome symptoms with myofascial trigger point symptoms in the posterior digastric and medial pterygoid are listed in Table 2 to aid the practitioner in isolating the SML insertion.10
A blunt small-headed probe, such as a Hu-Friedy #BB 27/29, can be used to apply pressure antero-medially to a small area during the evaluation (see Figure 2). If the ligament insertion is the source of the complaint, then pressure will produce intense pain and often referral to one or more of the sites previously mentioned. Prior to injecting, the site can be marked and should be cleaned with an antiseptic solution.
A 30-gauge needle with a short-duration, plain anesthetic (i.e. 3% carbocaine) is suggested for diagnostic purposes. Relocate the site with a probe and slowly insert the needle in close proximity to the probe in an antero-medial direction on the medial aspect of the mandible (see Figure 3). Often the patient will relate during the injection that the pain is being referred to one or all of the known referral sites.
Usually, the needle insertion depth is 10 to 15mm and ½ to 1 cc of anesthetic solution is deposited very slowly. Aspiration during the injection is very important because of the close proximity of major vascular structures to the SML attachment. The area is reevaluated after 10 minutes and if the patient has significant or complete pain remission, a diagnosis of Ernest syndrome is suspected. If only partial pain reduction is experienced, a second injection may be indicated, as some SML are very broad.1,4 Prior to the injection, the patient should be advised of the possibility of anesthesia to the facial nerve. Note that the duration of the analgesic effect may often outlast the anesthesia’s duration.11
|Ernest Syndrome||Temporal Tendinitis||TM Disorders||Occipital Neuralgia|
This study identified one hundred and twenty eight subjects with Ernest Syndrome from a group of two hundred and seventeen subjects having orofacial pain and/or TMD complaints (an incidence rate of 59%). Each individual in this study had a history of pain in one of the specific referred pain areas of Ernest syndrome listed previously. They also experienced pain when the insertion of the SML was palpated and had relief of pain when the SML insertion was anesthetized.
The location of the SML injury was determined in each subject as to being unilateral or bilateral and the number and sites of the subject’s pain complaints were charted. The subjects were questioned about the cause of onset of their SML pain and given a comprehensive physical examination with panoramic imaging. Imaging was used to rule out an elongated styloid process and/or ligament calcification. Each subject with positive findings was given an anesthetic injection at the painful SML insertion.