Mucin-producing tumor of the pancreas: diagnostic value of diffusion-weighted echo-planar MR imaging

It is generally accepted that hemifacial spasm (HFS) and trigeminal neuralgia are caused by compression of the facial nerve (seventh cranial nerve) or the trigeminal nerve (fifth cranial nerve) at the nerve's root exit (or entry) zone (REZ); thus, neurosurgeons generally perform neurovascular decompression at the REZ. Neurosurgeons tend to ignore vascular compression at distal portions of the seventh cranial nerve, even when found incidentally while performing neurovascular decompression at the REZ of that nerve, because compression of distal portions of the seventh cranial nerve has not been regarded as a cause of HFS. Recently the authors treated seven cases of HFS in which compression of the distal portion of the seventh cranial nerve produced symptoms. The anterior inferior cerebellar artery (AICA) was the offending vessel in five of these cases. Great care must be taken not to stretch the internal auditory arteries during manipulation of the AICA because these small arteries are quite vulnerable to surgical manipulation and the patient may experience hearing loss postoperatively. It must be kept in mind that compression of distal portions of the seventh cranial nerve may be responsible for HFS in cases in which neurovascular compression at the REZ is not confirmed intraoperatively and in cases in which neurovascular decompression at the nerve's REZ does not cure HFS. Surgical procedures for decompression of the distal portion of the seventh cranial nerve as well as decompression at the REZ should be performed when a deep vascular groove is noticed at the distal site of compression of the nerve.     

Hemifacial spasm in childhood and adolescence

Hemifacial spasm (HFS), a hyperactive dysfunction of the facial nerve, is rarely seen in young people. Between 1984 and 1994, we treated 924 patients with HFS by microvascular decompression at our institution. Of these, 8 (0.9%) were younger than 30 years. In most of the older patients with HFS, the offending artery which compresses the root exit zone was elongated, redundant, and focally arteriosclerotic as a result of hemodynamic effects due to aging or hypertension. On the other hand, the offending artery did not exhibit such characteristic changes of the vasculature in children and adolescents with HFS. In all of the young patients who underwent initial microvascular decompression at our clinic, the arachnoid membrane around the facial nerve was thickened and encased the artery, resulting in compression of the root exit zone of the facial nerve. Such thickening of the arachnoid surrounding the offending vessel may play an important role in the pathogenesis of HFS by trapping and encasing the artery to compress the root exit zone, particularly in the young patients.     

Hemifacial spasm: clinical findings and treatment

Hemifacial spasm (HFS) is a peripherally induced movement disorder characterized by involuntary, unilateral, intermittent, irregular, tonic or clonic contractions of muscles innervated by the ipsilateral facial nerve. We reviewed the clinical features and response to different treatments in 158 patients (61% women) with HFS evaluated at our Movement Disorders Clinic. The mean age at onset was 48.5+/-14.1 years (range: 15-87) and the mean duration of symptoms was 11.4+/-8.5 (range: 0.5-53) years. The left side was affected in 56% instances; 5 patients had bilateral HFS. The lower lid was the most common site of the initial involvement followed by cheek and perioral region. Involuntary eye closure which interfered with vision and social embarrassment were the most common complaints. HFS was associated with trigeminal neuralgia in 5.1% of the cases and 5.7% had prior history of Bell's palsy. Although vascular abnormalities, facial nerve injury, and intracranial tumor were responsible for symptoms in some patients, most patients had no apparent etiology. Botulinum toxin type A (BTX-A) injections, used in 110 patients, provided marked to moderate improvement in 95% of patients. Seven of the 25 (28%) patients who had microvascular decompression reported permanent complications and the HFS recurred in 5 (20%). Although occasionally troublesome, HFS is generally a benign disorder that can be treated effectively with either BTX-A or microvascular decompression.     

Vascular compression and cranial nerve diseases

This paper offers a review of cranial nerve rhizopathies caused by vascular compression of cranial nerves in the posterior cranial fossa. We present our results of microvascular decompression for trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia caused by compression of the 5th, 7th and 9th cranial nerves, respectively. After a median observation time of 38 months, 20 of 25 patients with trigeminal neuralgia were completely free of pain, and one patient reported more than 50% pain relief. Four out of five patients treated for hemifacial spasms were completely free of spasms. Of two patients treated for glossopharyngeal neuralgia, one reported complete pain relief, whereas the other reported less than 50% pain relief. No serious complications occurred. The results of microvascular decompression reported in the literature reviewed, including results of the treatment of tinnitus and positional vertigo due to compression of the 8th cranial nerve, hypertension due to compression of the 10th cranial nerve and spastic torticollis due to compression of the 11th cranial nerve. It is concluded that the rationale behind microvascular decompression is supported by an extensive amount of data.     

Antiphospholipid syndrome associated with progressive systemic sclerosis

Hemifacial spasm is a neurological disorder due to abnormal hyperactivity of the facial nerve. The most common cause of hemifacial spasm is a neuro-vascular conflict in the cerebellopontine angle between a vascular loop and the root of the facial nerve (96% of cases). Tumors are the cause of hemifacial spasm in only 1% of cases). The authors present their results in 100 patients who underwent microvascular decompression for essential hemifacial spasm between 1990 and 1995. They used microsurgical and endoscopic procedures by a minimal retrosigmoid approach in all cases. The most common offending vessels were the posterior inferior cerebellar artery (70%), the vertebral artery (41%) and the anterior inferior cerebellar artery (28%). An aberrant vein was found in 2 cases. There were 38% of multiple artery-nerve conflicts. Physiopathology of hemifacial spasm is explained by two principal theories: in the ephaptic theory, hyperactivity and an abnormal nervous impulse pathway are due to a short demyelinated area on the nerve trunk caused by the offending vessel, inducing short circuiting between adjacent nerve fibers. In the nuclear theory, hyperactivity of the facial nerve is due to an abnormal and automatic activity of the facial nerve nucleus itself, induced by the vessel. The authors used pre and postoperative electromyographic tests and intraoperative electromyographic tests. Their results tend to prove the nuclear theory. Ninety per cent of the patients had a good result, with a mean follow-up time of 30 months in 60 cases. In 82% of the cases, there was a total recovery after a single procedure. There was no mortality and no facial palsy. Hearing loss occurred in less than 5%.     

Differentiating attention-deficit/hyperactivity disorder from pervasive developmental disorder not otherwise specified

To discriminate between the various compressing vessels of the facial nerves in patients with hemifacial spasm, pre-operative oblique sagittal gradient-echo MR imaging was performed. Forty-two patients underwent pre-operative MR imaging and microvascular decompression. The MR images were divided according to findings into three groups as follows: Group A, a thick and/or long high-intensity line along the root exit zone (REZ) of the facial nerve; Group B, a thin and/or short high-intensity line along the REZ; and Group C, an unreliable image around the REZ. Fifteen images were classified as Group A, 19 as Group B, and 8 as Group C. In Group A, vertebral artery (VA) compression was confirmed intra-operatively in 12 cases and posterior inferior cerebellar artery (PICA) or anterior inferior cerebellar artery (AICA) compression in 3. In Group B, PICA or AICA compression was confirmed intra-operatively in all cases. In Group C, PICA or AICA compression was confirmed intra-operatively in 7 cases and no compression in one. In all cases of VA compression of the facial nerve, the oblique sagittal gradient-echo images demonstrated a thick and/or long high intensity line along the REZ. Oblique sagittal gradient-echo MR imaging is a useful preoperative planning aid, which can predict the possibility of VA compression prior to microvascular decompression for hemifacial spasm.     

Angina pectoris caused by coronary microvascular spasm

BACKGROUND: Microvascular angina can occur during exercise and at rest. Reduced vasodilator capacity of the coronary microvessels is implicated as a cause of angina during exercise, but the mechanism of angina at rest is not known. Our aim was to test the hypothesis that primary hyperconstriction (spasm) of coronary microvessels causes myocardial ischaemia at rest. METHODS: Acetylcholine induces coronary artery spasm in patients with variant angina. We tested the effects of intracoronary acetylcholine at graded doses in 117 consecutive patients with chest pain (at rest, during exertion, or both) and no flow-limiting (>50%) organic stenosis in the large epicardial coronary arteries. We also assessed the metabolism of myocardial lactate during acetylcholine administration in 36 of the patients by measurement of lactate in paired blood samples from the coronary artery and coronary sinus vein. FINDINGS: Of the 117 patients, 63 (54%) had large-artery spasm, 29 (25%) had microvascular spasm, and 25 (21%) had atypical chest pain. The 29 patients with microvascular spasm developed angina-like chest pain, ischaemic electrocardiogram (ECG) changes, or both spontaneously (two patients) or after administration of acetylcholine (27 patients) without spasm of the large epicardial coronary arteries. Testing of paired samples of arterial and coronary sinus venous blood showed that lactate was produced during angina attack in nine of 11 patients with microvascular spasm. There was more women (p<0.01) and fewer coronary risk factors (p<0.01) in patients with microvascular spasm than in those with large-artery spasm. INTERPRETATION: Coronary microvascular spasm and resultant myocardial ischaemia may be the cause of chest pain in a subgroup of patients with microvascular angina.     

Partial sensory rhizotomy as an alternative treatment of trigeminal neuralgia

Microvascular decompression is a well established technique in the treatment of medically refractory trigeminal neuralgia when a significant vascular contact is identified during posterior fossa exploration. However, in patients with recurrent trigeminal neuralgia after this type of surgery or if no significant vascular indentation is found during surgery, a partial sensory rhizotomy is often the preferred alternative mode of treatment. For eight such patients, partial sensory trigeminal rhizotomy was performed with the involved distribution. Two patients were cases of previous failure, while the other six cases showed a lack of vascular indentation during operation. All the patient underwent microvascular decompression in addition to partial sensory trigeminal rhizotomy with dissector disruption. Sensory examination was performed during the outpatient department follow-up. In these eight such patients, five had excellent results, two continued to have mild pain that was well controlled with carbamazepine, and one had poor results. The mean follow-up period was 58 months. Our study indicates that sensory loss is compatible with the extent of nerve section and that touch loss is less evidence than sensory loss. Partial sensory trigeminal rhizotomy is recommended as the alternative treatment strategy of choice for patients with trigeminal neuralgia who lack significant vascular contact during operation.     

Effect of repetitive stimulation on lateral spreads and F-waves in hemifacial spasm

The lateral spread (LS) response, which can be elicited in muscles innervated by other branches of the facial nerve, is electromyographycally specific for patients with hemifacial spasm (HFS), occurring about 10 ms after stimulus. The F-wave in facial muscles, which is a late response that antidromicaly propagates to the facial motonucleus and returns orthodromicaly down the same axon, revealed a trend toward enhancement in patients with HFS. The LSs were facilitated by repetitive stimulation during the microvascular decompression (MVD) operation, which has proved to be a successful treatment, and the F-waves were also facilitated by repetitive stimulation on the spasm side more than on the normal side. Greater facilitation of these responses was in direct proportion to higher stimulation rates and greater numbers of stimulations. The repetitive stimulation of the facial nerve may result in activation of the motoneuron pool and in the lowering of the threshold of somatic membranes. These results support the hypothesis that hemifacial spasm is caused by hyperexcitability of the facial motonucleus, which is increased by antidromic repetitive stimulation.     

Vascular compression of cranial nerves. I. History of the microvascular decompression operation

The development of the microvascular decompression (MVD) operation is reviewed. It is stressed that a few innovative neurosurgeons discovered the role of vascular compression of cranial nerves V and VII in trigeminal neuralgia (TGN) and hemifacial spasm (HFS) and developed an operation, later to be known as the MVD operation. While the understanding of the pathophysiology of these disorders has improved, the surgical procedure has undergone little change since Gardner described the operation about 1960.     

Glycation mediated lens crystallin aggregation and cross-linking by various sugars and sugar phosphates in vitro

BACKGROUND: The role of coronary spasm in underlying disease-free patients who were resuscitated from sudden cardiac arrest remained uncertain. This study investigated the cause of cardiac arrest, and the etiologic and prognostic differences were compared between patients with underlying heart disease (group I) and those patients without underlying heart disease (group II). METHODS: Twenty-five survivors of sudden cardiac arrest were classified into two groups according to the presence or absence of underlying heart disease. To investigate the cause of cardiac arrest, we performed ergonovine testing and electrophysiologic study. Fifteen of the patients had underlying heart disease, while 10 did not. RESULTS: Electrophysiologic abnormalities were found in 13 of the 15 patients in group I. In group II, spontaneous attack of coronary spasm occurred in four patients during the observation period, and coronary spasm was induced in three of the remaining six period of 32 +/- 23 months, whereas no patients in group II had recurrence of sudden cardiac arrest at a median follow-up of 32 months (range, 10 to 72 months). CONCLUSIONS: Electrophysiologic study identified a potential cause in 13 of 15 patients with underlying heart disease. Coronary spasm was involved in the pathogenesis of sudden cardiac arrest in survivors without identifiable underlying heart disease.     

Unruptured aneurysms presenting with mass effect symptoms: response to endosaccular treatment with Guglielmi detachable coils. Part I. Symptoms of cranial nerve dysfunction

OBJECT: Embolization of intracranial aneurysms by using Guglielmi detachable coils (GDCs) is proving to be a safe method of protecting aneurysms from rupture. Occasionally, patients with unruptured intracranial aneurysms present with symptoms related to the aneurysm's mass effect on either the brain parenchyma or cranial nerves. In the present study, the authors conducted a retrospective review to evaluate the response to GDC embolization in a series of 19 patients presenting with cranial nerve dysfunction due to mass effect. METHODS: Aneurysms were classified by size, shape, wall calcification, and amount of intraluminal thrombus. Patients were classified by duration of symptoms prior to GDC treatment (range < 1 month to > 10 years). Clinical assessment was performed within days of the GDC procedure and at later follow-up appointments (range 1-70 months, mean 24 months). In the immediate post-GDC period, four patients experienced worsening of cranial nerve deficits. Two of the four patients had transient worsening of visual acuity, which later improved to better than baseline status. Another patient who had presented with headache and seventh and eighth cranial nerve deficits from a vertebrobasilar junction aneurysm had improvement in these symptoms, but developed a new diplopia. The fourth patient had worsening of her visual acuity, which had not resolved at the 1-month follow-up examination; this patient later underwent surgical decompression. CONCLUSIONS: On late follow-up review, the response was classified as complete resolution of symptoms in six patients (32%), improvement in eight patients (42%), no significant change in four patients (21%), and symptom worsening in one patient (5%). Patients with smaller aneurysms and those with shorter pretreatment duration of symptoms were more likely to experience an improvement in their symptoms following GDC treatment, although statistical significance was not reached in this series (p=0.603 and p=0.111, respectively). The presence of aneurysmal wall calcification (six patients) or intraluminal thrombus (12 patients) showed no correlation with the response of mass effect symptoms in these patients.     

Surgical reconstruction of the musculocutaneous nerve in traumatic brachial plexus injuries

Over the last 16 years, 345 surgical reconstructions of the brachial plexus were performed using nerve grafting or neurotization techniques in the Neurosurgical Department at the Nordstadt Hospital, Hannover, Germany. Sixty-five patients underwent graft placement between the C-5 and C-6 root and the musculocutaneous nerve to restore the flexion of the arm. A retrospective study was conducted, including statistical evaluation of the following pre- and intraoperative parameters in 54 patients: 1) time interval between injury and surgery; 2) choice of the donor nerve (C-5 or C-6 root); and 3) length of the grafts used for repairs between the C-5 or C-6 root and the musculocutaneous nerve. The postoperative follow-up interval ranged from 9 months to 14.6 years, with a mean +/- standard deviation of 4.4 +/- 3 years. Reinnervation of the biceps muscle was found in 61% of the patients. Comparison of the different preoperative time intervals (1-6 months, 7-12 months, and > 12 months) showed a significantly better outcome in those patients with a preoperative delay of less than 7 months (p < 0.05). Reinnervation of the musculocutaneous nerve was demonstrated in 76% of the patients who underwent surgery within the first 6 months postinjury, in 60% of the patients with a delay of between 6 and 12 months, and in only 25% of the patients who underwent surgery after 12 months. Comparison of the final outcome according to the root (C-5 or C-6) that was used for grafting the musculocutaneous nerve showed no statistical difference. Furthermore, statistical analysis (regression test) of the length of the grafts between the donor (C-5 or C-6 root) nerve and the musculocutaneous nerve displayed an inverse relationship between the graft length and the postoperative outcome. Together, these results provide additional information to enhance the functional outcome of brachial plexus surgery.     

A Monte Carlo model for bone mineral measurement using dual energy X-ray absorptiometry

We discuss the surgical approach used for and outcome in 11 infants (< or =3 years) who were treated at our institution for ependymomas arising in the cerebellar-pontine (C-P) angle. The median age of the group was 19 months (range: 6-26 months). Of these 11 patients, the initial surgery for 8 was performed at our center and achieved a gross total resection (GTR) in 4 patients and a subtotal resection (STR) in the remaining 4. The 3 patients who had tumor debulking performed elsewhere were subsequently referred to our institution and had definitive surgery after receiving 3-4 courses of chemotherapy; one of these children had a GTR, whereas the remaining 2 had an STR. During the immediate postoperative period, 9 patients had cranial nerve deficits that necessitated placement of a tracheostomy and a gastrostomy feeding tube; these were discontinued in 6 of the 9 patients as the deficits resolved. The majority of the permanent cranial nerve deficits involved the sixth and seventh cranial nerves. Of the 11 patients, 4 have died (progressive disease, n = 1; accidental death, n = 2; withdrawal of life support, n = 1); the remaining 7 patients are alive, with a median follow-up of 37 months (range: 20-73 months). Aggressive surgical resection for tumors arising in the C-P region is associated with postoperative deficits, which resolve over time with appropriate supportive care. This approach may increase the number of children in whom GTR is achieved, thereby potentially increasing the cure rate for these patients.     

Mutation analysis of S182 (presenilin-I) in patients with familial Alzheimer''s disease and its biological function

OBJECTIVE: We studied the long-latency response of the orbicularis oris muscle elicited with transcranial magnetic stimulation in patients with hemifacial spasm (HFS) and evaluated the excitability of the facial nucleus. METHODS: We compared the thresholds on both sides in 8 normal volunteers and 7 patients with hemifacial spasm. The thresholds were determined as the lowest intensity required to produce motor evoked potentials with an amplitude of at least 50 microV in the orbicularis oris muscle. Average values were given as means +/- standard deviation. Wilcoxon's rank sum test was used for comparisons between the sides of normal subjects and of patients with HFS with respect to the threshold stimulus. RESULTS: There was no significant difference between the thresholds on the two sides of the normal subjects (mean 1.88+/-5.30%, P > 0.05). In patients with HFS, there was a significant difference between the thresholds on the spasm side and the normal side (mean 20.7+/-13.0%, P < 0.05) In one patient studied after MVD, the difference between both sides disappeared. CONCLUSION: The difference between the thresholds in patients with HFS and the normalization in threshold after MVD suggested that the mechanism of HFS was hyperexcitability of the facial nucleus.     

Effects of stress due to deprivation and transport in different genotypes of house mouse

37 patients with mixed cardiac pathologies were subjected to isometric exercise (hand grip) during routine cardiac catheterization. On the basis of a simple and safe grip test it was possible to distinguish three groups of patients according to the left ventricular pressure at rest and its response to this test. Group 1 consisted of 14 patients with left ventricular end diastolic pressures remaining below 12 mm Hg both at rest and on exercise. These patients were considered to have normal left ventricular function some, even in the presence of organic heart disease. No deaths occurred in this group during the follow-up period which averaged 33.8 months. At the other extreme (Group 3) there were 12 obviously disabled patients with resting left ventricular filling pressures above 12 mm Hg rising further under isometric stress. Six of these patients (50%) died during the period of the study. (Average follow-up 21.4 months). By the application of the hand grip test, an intermediate population (Group 2) of 11 patients was discernible. These patients were able to maintain a normal cardiac reserve at rest (LVEDP less than 12 mm Hg) but not during isometric effort (LVEDP greater than 12 mm Hg). Two of these patients (18%) died during the follow up period (average 22.1 months). Assuming a pathological progression with time from groups 1-3 and in view of the different prognoses observed in the course of the long-term follow-up it would appear that the Group 2 patients should be considered more critically and offered more active management.     

Jugulotympanic paraganglioma: therapy concepts under development

BACKGROUND: The operative treatment and radiation therapy of jugulotympanic paragangliomas (JTP) are still a matter of controversial discussion. In spite of various improvements during the last 50 years, selecting the appropriate treatment modality (surgery, radiation, or observation) is still a challenge. PATIENTS: During a 16-year period, 44 patients with 45 JTP (10 at level A/B and 35 at level C/D according to Fisch) were seen at the ENT-department in Fulda. Forty-one cases were treated surgically. RESULTS: Complete resection was possible for level A/B in 100% of the patients (n = 10). Residual tumor was demonstrated for level C in 23% of the patients (5/22) and for level D in 40% (4/10) with a median follow-up time of 69 months. In two cases residual tumor was treated by radiation. Six patients with residual paraganglioma tissue were maintained under observation without any evidence of tumor progression (median follow-up time 39 months). We report one death after the attempt to resect a large residual paraganglioma that had already caused brain stem compression. A sufficient duraplasty could not be achieved following radiation therapy. CONCLUSIONS: Complete tumor resection of jugulotympanic paragangliomas of levels A and B is often possible without injury to the cranial nerves. Extensive tumors present difficulties in complete tumor resection and increase the risk of cranial nerve injuries. Advanced paragangliomas therefore require an individualized therapeutic regime including surgery, radiation therapy, and observation of tumor growth.     

Medical imaging research on idiopathic hemifacial spasm

In order to have a medical imaging examination for idiopathic hemifacial spasm before surgery, we designed a new method by using vertebroarterial DSA and vertebroarterial CTA based on an aired cisternapontis, 36 patients were examined since 1989 and the compression of the facial nerve from brain stem to porus acousticus internus was showed clearly in all the cases. The arteries responsible for the compression were cerebellar inferior posterior (55.6%), cerebellar inferior anterior (44.4%), auditory internus (25.0%) and vertebroarterial (11.1%), 36% of all the cases had more than one responsible arteries, 22.2% cases had only one compression point, 38.9% had two points, 25.0% had 3 and 13.9% had more. 85.7% of the compression points located in the root zone and 14.3% near the porus acousticus internus. 24 cases were treated with decompression surgery, it indicated that the compression conditions just met the medical imaging examinationg results. After surgery the symptom disappeared in 23 cases and remarkably released in one case with no death case. We believed that this method might be helpful to idiopathic hemifacial spasm decompression surgery and other surgeries in the CP angle.     

Range of motion and complications after postburn heterotopic bone excision about the elbow

OBJECTIVE: To review the results of surgical management of heterotopic ossification about the elbow in burned patients. DESIGN: Retrospective analysis with long-term patient follow-up. MATERIALS AND METHODS: Eleven patients with 16 elbows requiring surgery were admitted between January 1, 1982 and December 31, 1993. A posterior approach to the elbow with release of the encased ulnar nerve +/- anterior transposition and transolecranon osteotomy to access extensive bone formation in the olecranon fossa was employed. Eight patients (11 elbows) were available for long-term follow-up conducted at mean 50 +/- 13 months after surgery. Long-term follow-up consisted of measurement of range of elbow motion, as well as clinical assessment of ulnar nerve function. MAIN RESULTS: For the 11 elbows examined postoperatively, the mean range of motion preoperatively in flexion-extension was 11 degrees +/- 5 degrees compared to 89 degrees +/- 12 degrees postoperatively (p < 0.001). Three patients with poor long-term results had ankylosis of the joint preoperatively. Of four patients with ulnar nerve paresis preoperatively, none had ulnar nerve dysfunction at follow-up. Of 16 elbows operated on, four (25%) had postoperative complications. Two suffered soft-tissue breakdown with hardware exposure requiring abdominal flap closure, one early failure of olecranon fixation, and one late infected hardware. CONCLUSIONS: Surgery for both limited range of motion as well as ulnar nerve compression is effective in cases of heterotopic ossification about the elbows of burned patients. Early operative intervention is indicated in progressive disease, particularly ulnar nerve palsy, if soft-tissue quality is adequate. Complications with 25% of elbows suggest that use of olecranon osteotomy for joint access may warrant review.     

The natural course of anterior disc displacement without reduction in the temporomandibular joint: follow-up at 6, 12, and 18 months

PURPOSE: The purpose of this study was to examine the natural course of anterior disc displacement without reduction in the temporomandibular joint (TMJ). PATIENTS AND METHODS: The subjects were patients who had been diagnosed as having anterior disc displacement without reduction in the TMJ, but who had not undergone any treatment. Forty-four patients were followed for 6 months, 38 for 12 months, and 22 for 18 months. Clinical signs and symptoms were evaluated at each follow-up, and the incidence of successful resolution was determined using the criteria established in 1984 by the American Association of Oral and Maxillofacial Surgeons. RESULTS: The range of motion increased at each time during the follow-up period. Tenderness in the TMJ and the masticatory muscles was alleviated, but the noise in the TMJ remained unchanged at each follow-up time. The incidence of successful resolution was 34.1% at 6 months, 50.0% at 12 months, and 68.2% at 18 months. CONCLUSIONS: The clinical signs and symptoms of anterior disc displacement without reduction tend to be alleviated during the natural course of the condition. This should be taken into consideration when anterior disc displacement without reduction is treated.