Myofascial Pain - Dysfunction Syndrome: a Dilemma for the Clinicians

Myofascial Pain - Dysfunction Syndrome: A Dilemma for the Clinicians

Abstract Ravi Patel1, Himanshu Arora2, The MPD syndrome is a psychophysiologically altered condition 3 4 involving the muscles of mastication and cervical group of muscles. The Sarfaraz Memon , Usha Sharma , Ramjee Lal Raigar5, Anant Raghav condition characterized by dull aching, radiating pain often results in 6 muscle spasm and restricted movements. Frequently, myofascial pain is Sharma overlooked as a common cause of chronic pain because of frequent 1General Practitioner, Dr Ravi’s Dental Clinic, association with joint dysfunction and other pain disorders. Thus, the Surat, Gujarat, India therapy should be directed towards reducing stress, rehabilitating the 2Senior Lecturer, Department of occlusion and relaxing the muscles to alleviate the condition. Prosthodontics, Crown and Bridge Key Words Implantology, Manubhai Patel Dental College, Vadodara, Gujarat, India Myofascial; pain; temporomandibular joint 3Senior Lecturer, Department of Prosthodontics, Crown and Bridge Implantology Manubhai Patel Dental College, Vadodara, Gujarat, India 4Senior Lecturer, Dept. of Oral Pathology, KM Shah Dental College & Hospital, Vadodara, Gujarat, India 3Post- Graduate Student, Department of Prosthodontics, Crown and Bridge Implantology, RUHS College of Dental Science, Jaipur, Rajasthan, India 4Senior Lecturer, Department of Periodontics, Pacific Dental College, Udaipur, Rajasthan, India

INTRODUCTION Temporomandibular joint pain dysfunction Facial pain and its diagnosis have always posed a syndrome is a term covering a variety of problems dilemma for the clinicians. The complex anatomy of which include the entire scope of the region compounded with the variability of temporomandibular joint disorders originating symptoms involved, present a challenging situation either intra articular or extra articular.[1] Myofascial during the management of orofacial pain. The study pain-dysfunction syndrome is a psychophysiologic of temporomandibular joint appears to hold an disease that primarily involves the muscles of uncommon fascination for clinicians of many mastication. The condition is characterized by dull, disciplines. The dysfunction of these joint results in aching, radiating pain that may become acute during a large proportion of complaints presented to the use of the jaw, and mandibular dysfunction that dentists. With ever increasing refinements in generally involves a limitation of opening.[2] diagnostic and treatment modalities, dramatic Frequently, myofascial pain is overlooked as a advances have been made in understanding the common cause of chronic pain because of frequent causes of facial pain related to joint and surrounding association with joint dysfunction and other pain musculature. Still the mystery exists regarding the disorders. precise diagnosis and treatment of facial pain. ETIOLOGY Differentiation between temporomandibular The myofascial pain-dysfunction syndrome has a joint pain-dysfunction syndrome and myofascial multicausal etiology and the knowledge about the pain-dysfunction syndrome probable etiological factors seem to have improved over a period of time. Goodfriend (1933),[1] Costen 39 Myofascial Pain-Dysfunction Syndrome Patel R, Arora H, Memon S, Sharma U, Raigar RL, Sharma AR

Fig. 1: Etiology of the myofascial pain-dysfunction Fig. 2: The concept of “etiologic circle” is useful to

syndrome understand the mechanism of TMJ dysfunction

Fig. 3: Pathophysiology of this stress disorder of skeletal Fig. 4: Medication Thearpy

muscles

(1934)[1] and many others initially advocated the facial pain occurred when Laskin (1969)[1] probable etiologies for the dysfunction syndrome. presented a comprehensive explanation of the Pathologies of temporomandibular joint, trauma, problem and proposed his psychophysiological occlusal disharmony and many other factors have theory. He suggested that though mechanical factors been proposed by different authors. Lot of related to occlusion may cause this condition by confusion existed until, Travell and Rinzler[1] first producing muscular overextension or suggested that skeletal muscles in spasm could be overcontraction leading to muscle fatigue but the source of pain. They described about the painful psychophysiologically motivated oral habits is the areas within the muscles and called them as frequent cause of painful spasm. To stress the role “Trigger areas” which were associated with pain, played by muscles, it was suggested that the term spasm, tenderness and dysfunction. Schwartz myofascial pain dysfunction syndrome is a more (1955)[1] adapted Travell’s work and postulated the accurate term to describe the condition than term temporomandibular joint pain-dysfunction temporomandibular joint pain-dysfunction syndrome. He reported that majority of patients syndrome. Laskin pointed out the key elements of with pain in the region of temporomandibular joint the theory of MPD dysfunction.[3] Fig. 1 shows were suffering from functional disorders involving Etiology of the myofascial pain-dysfunction painful spasm of masticatory musles. He syndrome. Although there are three means of entry hypothesized that stress was a significant cause of into the syndrome. The darker arrows indicate that clenching and grinding habits which resulted in most common pathway. The explanation of this muscle spasm. Occlusal abnormalities were found mechanism is termed the psychophysiologic theory. to play a secondary role. The next significant Laskin’s theory is an outgrowth of work of development towards understanding this aspect of Schwartz and is based on premise that MPD 40 Myofascial Pain-Dysfunction Syndrome Patel R, Arora H, Memon S, Sharma U, Raigar RL, Sharma AR syndrome is primarily a result of emotional rather myospasm is triggered by emotional disturbances than occlusal or mechanical factors. The and may be due to a combination of psychologic masticatory muscle spasm is the primary factor stress and muscle incordination secondary to responsible for signs and symptoms of pain- malocclusion. To complete the understanding for dysfunction syndrome. Spasm can be initiated in etiology of MPD syndrome, it is essential to one of the three ways: 1) muscular over extension, eliminate the possibility of medically linked factors, 2) muscular overcontraction, or 3) muscle fatigue. recent major surgical operations or trauma to head The myofascial pain syndrome so produced not only and neck which can give signs and symptoms of causes pain and limitation of movement but also MPD syndrome. produces changes in jaw position so that teeth don’t PATHOPHYSIOLOGY OF MPD SYNDROME occlude properly (occlusal disharmony). In addition As explained by Travell (1960),[5] the it may also cause organic changes such as pathophysiology of this stress disorder of skeletal degenerative changes in the TMJ and muscle muscles is outlined on Fig. 3. It has been observed contraction which is a manifestation of long-term that whenever the pain associated with skeletal spasm. These organic changes result in an altered muscle spasm is very severe, it is referred to a site chewing pattern with attendant reinforcement of the from the muscle that is its source. The pain is original spasm and pain. The changes in referred from a small area of hypersensitivity neuromuscular control of mandible produced due to located within the muscle or the fascia. These areas occlusal disharmony has been supported by many are termed as Trigger areas. The response of researchers. Irregularities in occlusion appear to be muscles against the injury tends to gain momentum the precipitating factor in pathogenesis of MPD and results in a self representating cycle of spasm- syndrome. Occlusal interferences, posterior bite pain-spasm which limits the movements and result collapse, deep overbite/overjet and many other in fibrosis of tissues. factors tend to restrict movement and predispose the Clinical Features patients to increased parafunctional activity Incidence resulting in overuse and thus fatigue of muscles. Women are affected by MPD syndrome more Moreover Bruno (1971)[1] found that the resulting frequently than men, with the ratio ranging from 3:1 pain in muscles will be concentrated in areas of to 5:12. The greatest incidence appears to be in the fascia which upon palpation demonstrated 20 to 40 years age group.[2] The patients suffering tenderness and pain and these areas were referred to from MPD syndrome usually present with as trigger areas. According to Weinberg (1974),[1] complaint of: every patient has got adaptation to a situation which  Pain in a zone of reference (most important is determined by his psychological make up. In a problem that causes patients to seek given patient, an occlusal interference may trigger treatment). the patient’s acute symptoms while another factor,  Trigger points in muscles which cause pain on [2,3] such as emotional stress may sustain them. stimulation. Evidence that nocturnal parafunction may be  Taut muscle band. involved in MPD syndrome stemmed from studies  Limited jaw opening. [4] by Trenouth (1978) who observed that jaw pain  Associated symptoms. and limitation of movement were often noted to be  Presence of contributing factors for onset of Christensen [4] worse on awakening. (1981) and pain. Yemm (1979)[4] demonstrated that in chronic cases  No tenderness in temporomandibular joint. of MPD syndrome, an inflammatory stage occurs in Mode of Onset affected muscles of mastication following the The patients suffering from MPD syndrome may classic spasm. This myositis perpetuates the complain of: symptoms of pain and dysfunction. So, it can be i. Sudden onset of pain and trismus, characterized seen that one school of thought supported occlusal by forcible contraction of muscle during biting disharmony as the major etiological factor of the on a hard object, overstretching of jaws, difficult development of MPD syndrome, but it could not tooth extraction etc. explain why pain and dysfunction are uncommon in ii. Gradual onset characterized by appearance of patients with severe malocclusion. It is now abnormal sounds in the joint followed by pain recognized that hyperactivity of muscles leading to and limited jaw motion. Major precipitating 41 Myofascial Pain-Dysfunction Syndrome Patel R, Arora H, Memon S, Sharma U, Raigar RL, Sharma AR Table 1 Complete blood cell count If infection is suspected. Serum calcium, phosphorous and alkaline phosphatase measurement. For bone diseases. Serum uric acid determination. For gout. Serum ceratinine and creatine phosphokinase levels. Indicators of muscle disease. ESR, Rheumatoid factor, Latex fixation test. For rheumatoid arthritis. EMG For muscle function evaluation. Psychologic evaluation and psychometric testing. For behavioural responses.

factor may be strain of muscles due to occlusal d) Otologic symptoms: Tinnitus, ear pain and imbalance or asymmetry of face. diminished hearing. iii. May be associated with oral foci of infection, e) Other symptoms: Scratchy sensation, teeth respiratory infection, or acute emotional stress. sensitivity, increased salivation, increased Trigger points / Trigger zones / Trigger areas sweating and skin flushing.  Myofascial pain is characterized by pain referred Management of MPD Syndrome from few hypersensitive areas termed as trigger I Diagnosis of the condition areas / zones. A trigger point is defined as a The cardinal signs and symptoms of MPD localized tender area in taut band of skeletal syndrome are similar to those produced by many muscle, tendon or ligaments. organic problems involving the temporomandibular  Points occur frequently in head, neck, shoulder, joint and other non-articular conditions. Therefore, lower back. a careful history and thorough examination may be  Any pressure on these areas may initiate pain helpful in diagnosing the condition. Radiographs referred to distant areas (called as zone of may be helpful in diagnosing the condition if it has reference). affected the bony structure also. X rays include:  Trigger areas develop due to direct / indirect Transcranial, transpharyngeal, panoramic views, CT trauma (parafunctional habits) to muscles, due to scans and MRI with arthroscopy can provide weakening of muscles (nutritional disturbances, reliable diagnosis of the condition. Arthrography lack of exercise, structural disharmony etc.). can be useful in determining the position of  Trigger points range from 2.5mm in diameter meniscus (when internal derangement of and may be active or latent. temporomandibular joint is being considered). 1. Certain lab tests are helpful  Palpating trigger points with deep finger pressure, elicits alteration in pain, in the zone of Shown on Table 1. Differential diagnosis of MPD syndrome reference or causes radiation of pain towards the Non articular conditions that mimic MPD zone of reference. a) syndrome: Pulpitis, Pericoronitis, Otitis media,  Patients behavioural reaction to firm palpation Parotitis, Sinusitis, Trigeminal neuralgia, of trigger points is a distinguishing characteristic Atypical (vascular) neuralgia, Temporal of myofascial pain and is termed a positive arthritis, Trotters syndrome, Eagle’s syndrome. ‘jump sign’. This reaction may include: Non articular conditions producing limitation a. Withdrawal of head. b) of mandibular movement: Odontogenic b. Wrinkling of face or forehead and infection, Non-odontogenic infection, Myositis, desensation of skin. Myositis ossificans, Neoplasia, Scleroderma, In locating an active trigger point, jump sign should Hysteria, Tetanus, Extra pyramidal reaction, be elicited. Signs and symptoms of myofascial pains are Depressed zygomatic arch, Osteochondroma. Differential diagnosis of temporomandibular often accompanied by other pathological c) joint disease: conditions and other problems such as: Agenesis, Condylar hypoplasia, Condylar hyperplasia, Neoplasia, Infectious a) Neurologic: Tingling, numbness, blurred vision arthritis, Rheumatoid arthritis, Traumatic and excess lacrimation. arthritis, Degenerative arthritis, Ankylosis, b) Gastrointestinal: Nausea, constipation and Internal disk derangement. indigestion. It is not possible to discuss signs and symptoms of c) Musculoskeletal: Fatigue, tension, stiff joints these conditions at this juncture but a careful and muscle twitching. evaluation should rule out these conditions.

42 Myofascial Pain-Dysfunction Syndrome Patel R, Arora H, Memon S, Sharma U, Raigar RL, Sharma AR

II Treatment of MPD syndrome increase in tissue elasticity. Moreover there is The treatment of MPD syndrome should be geared mild analgesic and anti-inflammatory action. towards complete management rather than Lasts for 10-15 minutes, given twice daily for 1- symptomatic cure. Several treatment modalities 2 weeks. have been recommended for MPD syndrome. ii) High voltage electrogalvanic stimulation 1. Initial explanation of the problem involves the use of monophasic, pulsed direct The patients should be explained about the problem current applied through an electrode placed on and its probable etiology. The psychophysiologic skin over the involved muscle. Activated at factor shouldn’t be stressed while explaining the frequencies from 4-80 pulse per second, for 10- problem because patient may not accept it. Initial 15 minutes, 2-3 times a week. Stimulation of discussion should deal with muscle fatigue, spasm muscle increases circulation, reduces pain and and explaination about the condition. spasm and increases resistance to fatigue. 2. Therapeutic modalities of treatment iii) Cryotherapy (cold therapy) a. Therapy at home  Reduces tissue temperature, causes local  Intake of soft diet with small cut pieces. Jaw analgesia and has anti-inflammatory effects and motion should be limited and wide opening diminishes muscle spasm. should be avoided. Parafunctional habits such as  Cooling effect also creates vasoconstriction, clenching, grinding should be avoided (although reduces myoneural transmission and patients are unaware of these habits, they should neuromuscular activity. be instructed to check for clenching). Other  Vapour coolant spray (such as ethyl chloride or habits such as fingernail biting, lip biting etc. fluorimethane) is applied over the involved should be avoided. muscle by spraying for 10 seconds. Repeated for  Intermediate moist heat application for half an two more times with 10 seconds interval. hour twice daily. Mandible is mobilized by gently stretching to  Massage of the affected area using moderate maximum opening (also termed as spray and kneading motion. This helps in return of venous stretch activity). blood, lymph and catabolites and reduces  Ice packs can be useful in acute phases of MPD muscle pain and spasm. syndrome. Cold application is used for 10-15 b. Short term medication minutes; removed and reapplied after 5 to 10  Shown on Fig. 4. minutes, 3-4 times daily. c. Splint therapy e. Relaxation therapy  If previously described forms of therapy are not Because MPD syndrome is basically a problem successful or there is h/o tooth clenching etc., related to increased muscle tension and spasm, splint therapy should be considered. any technique designed to induce muscle  According to Kawazoe,[6] 4 types of splints are relaxation should be helpful. Among the used: modalities that have proven to be effective are i. Stabilization splint biofeedback, conditioned relaxation and ii. Relaxation splint hypnosis. iii. Resilient splint i. Biofeedback iv. Pivoting splint  EMG biofeedback involves supplying the  Hawley’s type upper anterior splint is most patient with visual or auditory information about effective because it prevents occlusion of the moment to moment contractile status of posterior teeth and thereby prevents muscle being monitored. The patient then parafunctional activity. It is worn at night and 5- concentrates on relaxing the muscle and is 6 hours of day. Shouldn’t be worn continuously reflected by reduction in level of graphic as it results in supraeruption of posterior teeth. representation or audible sound. Platform of the splint should be flat.  The biofeedback is used for two 30-minutes d. Physical therapy sessions each week for 6 weeks. i) Ultrasound produces vibrations within the tissue Clarke and Kardachi (1977)[8] used biofeedback that cause particle collision and release of method in 7 patients suffering from MPD syndrome energy. This results in production of heat and and achieved success by controlling parafunctional vibration which reduces the muscle tension and habits. Dohrmann and Laskin (1978)[7] noted 43 Myofascial Pain-Dysfunction Syndrome Patel R, Arora H, Memon S, Sharma U, Raigar RL, Sharma AR significant reduction in massetric EMG levels of 3. Laskin DM. Etiology of the pain-dysfunction patients treated with biofeedback. syndrome. J Am Dent Assoc 1969;79:147-51. ii. Conditioned relaxation 4. Lynch MA, Brightman VJ, Greenberg MS. Similar to biofeedback in its end results but differs Burket’s oral medicine: Diagnosis and in that the patients do not have the benefit of a treatment. ed. 9, Lippincott-Raven, Philadelphia. feedback indicator. 1997. iii) Other methods are hypnosis, transcendental 5. Travell J. Temporomandibular joint pain mediation (TM) and yoga can also be useful in referred from muscles of the head and neck. J the treatment of MPD syndrome. Prosthet Den 1960;10:745-63. f. Anesthetic injections 6. Kawazoe Y, Kotani H, Hamada T, Yamada S.  Useful in extremely painful conditions. The Effect of occlusal splints on the injection of LA into tender and painful areas in electromyographic activities of masseter muscle has been used for diagnostic and muscles during maximum clenching in patients therapeutic purposes in patients with MPD with myofascial pain-dysfunction syndrome. J syndrome. Prosthet Dent 1980;43:578-80.  0.5cc of LA that does not contain epinephrine or 7. Dohrmann RJ, Laskin DM. An evaluation of other vasoconstrictors are used. electromyographic biofeedback in the treatment g. Transcutaneous Electrical Nerve Stimulation of myofascial pain-dysfunction syndrome. J Am TENS Dent Assoc 1978;96:656-62.  The use of TENS is based on the concept that 8. Clarke NG, Kardachi BJ. The treatment of stimulation of cutaneous branches of fifth nerve myofascial pain-dysfunction syndrome using the (trigeminal) creates an inhibitory effect on the biofeedback principle. J Periodont 1977;48:643- trigeminal spinal tract nucleus, thus reducing the 5. awareness of pain and relaxing the muscles.  Therapy lasts 30 minutes and should be repeated daily. III. Final explanation of problem.  When patients with MPD syndrome begin to show improvements of their symptoms and have gained confidence in doctors ability to deal with their problem, the relationship between stress and MPD syndrome should be discussed and explained. IV. Psychologic Counseling  A group of patients are sometimes not able to identify and understand relationship between stress/strain and MPD syndrome and are unable to cope with stressful conditions. Such patients should be referred to psychologists or psychiatrist for counseling. Psychological interventions are aimed at reducing high level of muscle tension or modifying the environment.  Treatment of contributing factors should be carried out. REFERENCES 1. Mikhail M, Rosen H. History and etiology of myofascial pain-dysfunction syndrome. J Prosthet Dent 1980;44:438- 44. 2. Laskin DM, Sanford B. Diagnosis and treatment of myofascial pain-dysfunction (MPD) syndrome. J Prosthet Dent 1986;56:75-84.