Humoral Mechanisms in Immune Neuropathies

Risk of Bell's palsy following SARS-CoV-2 infection: a nationwide cohort study

OBJECTIVES

Despite some evidence of an increased risk of neurologic symptoms following viral vector COVID-19 vaccine administration, it is unclear whether SARS-CoV-2 infection is associated with Bell's palsy (BP), especially over a long enough follow-up period.

METHODS

The study population of this nationwide population-based study was derived from the South Korean population, including 11 593 365 and 36 565 099 participants with and without COVID-19, respectively. The Fine and Gray's regression model was utilized to calculate the adjusted subdistribution hazard ratio (aSHR), considering death as a competing risk, to assess the association between SARS-CoV-2 infection and the risk of BP. All participants were followed up from 1 December 2021, until the incident BP, SARS-CoV-2 infection, death, or 31 March 2022. Subgroup analyses were conducted based on participants' vaccination status (completion of the primary series vs. unvaccinated).

RESULTS

COVID-19 was associated with an increased risk of BP in all participants (aSHR, 1.24; CI, 1.19-1.29). However, the size of the COVID-19-related BP risk was significantly lower among those who completed the primary series of the COVID-19 vaccine (aSHR, 1.20; 95% CI, 1.15-1.25) compared to those who were unvaccinated (aSHR, 1.84; 95% CI, 1.59-2.12; p for interaction: <0.001). The severity of COVID-19 exhibited a gradual escalation in BP risk for both vaccinated and unvaccinated individuals.

DISCUSSION

While both unvaccinated individuals and those who completed the primary series of the COVID-19 vaccine may be at an increased risk of developing BP due to COVID-19, the risk appears to be lower among those who completed the vaccination.

Bell's palsy following vaccination with mRNA (BNT162b2) and inactivated (CoronaVac) SARS-CoV-2 vaccines: a case series and nested case-control study

BACKGROUND

Bell's palsy is a rare adverse event reported in clinical trials of COVID-19 vaccines. However, to our knowledge no population-based study has assessed the association between the inactivated SARS-CoV-2 vaccines and Bell's palsy. The aim of this study was to evaluate the risk of Bell's palsy after BNT162b2 and CoronaVac vaccination.

METHODS

In this case series and nested case-control study done in Hong Kong, we assessed the risk of Bell's palsy within 42 days following vaccination with BNT162b2 (Fosun-BioNTech [equivalent to Pfizer-BioNTech]) or CoronaVac (from Sinovac Biotech, Hong Kong) using data from voluntary surveillance reporting with the Hospital Authority, the COVID-19 Vaccine Adverse Event Online Reporting system for all health-care professionals, and the Hospital Authority's territory-wide electronic health records from the Clinical Data Analysis and Reporting System. We described reported cases of Bell's palsy among vaccine recipients (aged 18-110 years for CoronaVac and aged 16-110 years for BNT162b2). We compared the estimated age-standardised incidence of clinically confirmed cases among individuals who had received the CoronaVac or BNT162b2 vaccination (up to 42 days before presentation) with the background incidence in the population. A nested case-control study was also done using conditional logistic regression to estimate the odds ratio (OR) for risk of Bell's palsy and vaccination. Cases and controls were matched (1:4) by age, sex, admission setting, and admission date.

FINDINGS

Between February 23 and May 4, 2021, 451 939 individuals received the first dose of CoronaVac and 537 205 individuals received the first dose of BNT162b2. 28 clinically confirmed cases of Bell's palsy were reported following CoronaVac and 16 cases were reported following BNT162b2. The age-standardised incidence of clinically confirmed Bell's palsy was 66·9 cases per 100 000 person-years (95% CI 37·2 to 96·6) following CoronaVac vaccination and 42·8 per 100 000 person-years (19·4 to 66·1) for BNT162b2 vaccination. The age-standardised difference for the incidence compared with the background population was 41·5 (95% CI 11·7 to 71·4) for CoronaVac and 17·0 (-6·6 to 40·6) for BNT162b2, equivalent to an additional 4·8 cases per 100 000 people vaccinated for CoronaVac and 2·0 cases per 100 000 people vaccinated for BNT162b2. In the nested case-control analysis, 298 cases were matched to 1181 controls, and the adjusted ORs were 2·385 (95% CI 1·415 to 4·022) for CoronaVac and 1·755 (0·886 to 3·477) for BNT162b2.

INTERPRETATION

Our findings suggest an overall increased risk of Bell's palsy after CoronaVac vaccination. However, the beneficial and protective effects of the inactivated COVID-19 vaccine far outweigh the risk of this generally self-limiting adverse event. Additional studies are needed in other regions to confirm our findings.

FUNDING

The Food and Health Bureau of the Government of the Hong Kong Special Administrative Region, China.

TRANSLATION

For the Chinese translation of the abstract see Supplementary Materials section.

Epidemiological and clinical aspects of Guillain-Barré syndrome and its variants

BACKGROUND

Guillain-Barré syndrome (GBS), an acute polyradiculoneuropathy that occurs because of an abnormal inflammatory response in the peripheral nervous system, is clinically characterized by acute flaccid paresis and areflexia with or without sensory symptoms. This syndrome can lead to disabling or even life-threatening sequelae.

OBJECTIVE

This study aimed to present the clinical and epidemiological aspects of GBS in patients admitted to a tertiary-level hospital in the Federal District between January 2013 and June 2019.

METHODS

In this observational, cross-sectional and retrospective study, medical records of patients diagnosed with acute inflammatory demyelinating polyradiculoneuropathy, acute motor axonal neuropathy or acute axonal motor-sensitive neuropathy based on electromyographic findings were included, and clinical data were collected retrospectively.

RESULTS

A total of 100 patients (63 males and 37 females; ratio, 1.7:1) aged 2-86 years (mean, 36.4 years) were included. The mean annual incidence rate of GBS was 0.54 cases/100,000 inhabitants, with 52 and 49% of the cases occurring between October and March (rainy season) and between April and September (dry season), respectively. The proportions of patients showing each GBS variant were as follows: demyelinating forms, 57%; axonal forms, 39%; and undetermined, 4%. The mean duration of hospitalization was 8-15 days for most patients (38%). During hospitalization, 14% of the patients required mechanical ventilation and 20% experienced infectious complications.

CONCLUSION

The findings indicate that there was an increase in the incidence of GBS during the rainy season. Moreover, we did not observe the typical bimodal distribution regarding age at onset.

Syncope after Influenza Virus Infection

Influenza is an epidemical acute respiratory disease caused by viral infection. Several complications in the respiratory tract, such as pneumonia can occur. However, rare but serious neurological complications are also observed. Here, we described the prevalence, characteristics and suggestive pathomechanism of syncope after influenza infection season. Of 2.2% of patients diagnosed as influenza experienced syncope. None of the patients had severe cough, low blood pressure (BP) or dehydration. Patients suffered with frequent dizziness before syncope. Patient with long duration of loss of consciousness was more observed in those with high fever or positive orthostatic BP drop.

Severe gastrointestinal bleeding and thrombocytopenia in a child with an anti-GATA1 autoantibody

We describe a patient, who developed during the first week of life petechiae and hematomas caused by severe thrombocytopenia and gastrointestinal bleeding due to multiple small gastric hemangiomata. Bone marrow examination showed hypermegakaryocytosis and dysmegakaryopoiesis. Alloimmune thrombocytopenia was excluded. Only 3 y later, platelet counts normalized and bleedings disappeared but small skin hemangiomata remained. Electron microscopy showed enlarged round platelets with a paucity of alpha granules similar as in GATA1-deficient patients but no GATA1 mutation was found. Immunoblot analysis showed a strong interaction between patient Igs and recombinant GATA1, GATA2, and the N finger (Nf) of GATA1. The lymphocyte transformation test with recombinant GATA1Nf was positive. In vitro culturing of normal CD34 cells with purified patient Igs showed a decreased number of megakaryocyte colonies but an increased overall size of the colonies compared with control Igs. Mice injected with patient Igs showed a reduced platelet count compared with mice injected with control Igs. Thrombopoiesis was also reduced after injection of patient Igs in transgenic zebrafish compared with control Igs. In conclusion, this study is the first report of an anti-GATA1 autoantibody leading to severe thrombocytopenia and gastrointestinal bleeding from multiple pinpoint hemangiomata.

JNK1 activation mediates C5b-9-induced P0 mRNA instability and P0 gene expression in Schwann cells

The protein zero (P0) glycoprotein is an important component of compact peripheral nerve myelin produced by the glial cells of the mammalian peripheral nervous system. P0 mRNA expression is reduced following exposure of Schwann cells to sublytic C5b-9, the terminal activation complex of the complement cascade. Sublytic complement treatment decreased P0 mRNA by 81% within 6 h and required C5b-9 assembly. C5b-9 induced a threefold increase in both JNK1 activity and c-jun mRNA within 20 and 30 min, respectively, compared with cells treated with either human serum depleted of complement component C7 (C7dHS) or medium alone. Sublytic C5b-9 stimulation, in the presence of the transcription inhibitor Actinomycin D, decreased P0 mRNA expression by 52%, indicating that mRNA was selectively destabilized. This effect was prevented by pretreatment with L-JNK inhibitor 1 (L-JNKI1). To study a potential inhibition of P0 gene transcription, we transfected Schwann cells with a P0 promoter-firefly luciferase construct. Sublytic C5b-9 stimulation of the transfected cells decreased luciferase activity by 82% at 6 h, and this effect was prevented by pretreatment with L-JNKI1 inhibitor. Our results indicate that the ability of C5b-9 in vitro to affect P0 gene expression is mediated via JNK1 activation that leads to enhanced mRNA decay and transcriptional repression of P0.

Postherpetic neuralgia: topical lidocaine is effective in nociceptor-deprived skin

OBJECTIVES

Topical lidocaine is effective in postherpetic neuralgia (PHN). The aim of the present investigation was to classify patients according to their predominant peripheral nociceptor function and to compare these data with the results of a controlled study using dermal lidocaine patch.

METHODS

Within the skin area of maximal pain QST (thermotest) and QCART (histamine iontophoresis and laser Doppler flowmetry) were performed prospectively in 18 PHN patients. A controlled study using cutaneous lidocaine (lidocaine 5% patch, IBSA) followed.

RESULTS

Six patients (group I, sensitised nociceptors) had no sensory loss. Heat pain thresholds were equal or lower than on the contralateral side. Histamine-induced flare and axon reflex vasodilatation were not different on both sides. Histamine evoked pain increased. In 12 patients (group II, nociceptor impairment) heat pain thresholds were higher than contralateral. Histamine-induced flare was impaired or abolished. Histamine did not induce any sensation. Lidocaine was efficacious in the entire group of patients. Subgroup analysis revealed that patients with impairment of nociceptor function had significantly greater pain reduction under lidocaine vs placebo. Patients with preserved and sensitised nociceptors demonstrated no significant pain relief.

CONCLUSIONS

PHN patients differ concerning their cutaneous nociceptor function: In the group I pain is caused by pathologically sensitised nociceptors. In subset II there is a loss of function of cutaneous C-nociceptors within the allodynic skin. Patients responded well to topical lidocaine even if the skin was completely deprived of nociceptors. Different underlying mechanisms of lidocaine action in nociceptor-deprived skin are discussed.

Epidemiologic features of Guillain-Barré syndrome in São Paulo, Brazil

INTRODUCTION

There are few epidemiologic studies concerning Guillain-Barré syndrome (GBS). Due to difficulties with definition and lack of a standard diagnostic test of reference, GBS is not easy to study epidemiologically. We evaluate some epidemiological features of GBS in a sample of cases treated at a tertiary hospital in São Paulo, Brazil.

METHOD

We retrospectively reviewed all cases of GBS with hospitalization in Santa Marcelina hospital, over the period of January 1995 through December 2002.

RESULTS

Ninety-five cases were included in this study. Fifty-five were men and forty women, with a proportion of 1.4 men to 1 woman. The age ranged from 1 to 83 years with a mean age at onset of 34 years. GBS was less frequently observed below 15 years (18.9%) and above 60 years (16.9%). The highest frequency was observed in patients aged 15 to 60 years old (66.2%). The annual incidence rate was 0.6 cases/100,000 people. There was a highest frequency of cases during the months of September through March (62.1%).

CONCLUSION

Our data differs from that of other epidemiological studies in that we did not observe a bimodal distribution in age and found a seasonal pattern in hotter months.

Beyond neurons: evidence that immune and glial cells contribute to pathological pain states

Chronic pain can occur after peripheral nerve injury, infection, or inflammation. Under such neuropathic pain conditions, sensory processing in the affected body region becomes grossly abnormal. Despite decades of research, currently available drugs largely fail to control such pain. This review explores the possibility that the reason for this failure lies in the fact that such drugs were designed to target neurons rather than immune or glial cells. It describes how immune cells are a natural and inextricable part of skin, peripheral nerves, dorsal root ganglia, and spinal cord. It then examines how immune and glial activation may participate in the etiology and symptomatology of diverse pathological pain states in both humans and laboratory animals. Of the variety of substances released by activated immune and glial cells, proinflammatory cytokines (tumor necrosis factor, interleukin-1, interleukin-6) appear to be of special importance in the creation of peripheral nerve and neuronal hyperexcitability. Although this review focuses on immune modulation of pain, the implications are pervasive. Indeed, all nerves and neurons regardless of modality or function are likely affected by immune and glial activation in the ways described for pain.

A new model of sciatic inflammatory neuritis (SIN): induction of unilateral and bilateral mechanical allodynia following acute unilateral peri-sciatic immune activation in rats

Immune activation near healthy peripheral nerves may have a greater role in creating pathological pain than previously recognized. We have developed a new model of sciatic inflammatory neuritis to assess how such immune activation may influence somatosensory processing. The present series of experiments reveal that zymosan (yeast cell walls) acutely injected around the sciatic nerve of awake unrestrained rats rapidly (within 3h) produces low threshold mechanical allodynia in the absence of thermal hyperalgesia. Low (4 microg) doses of zymosan produce both territorial and extra-territorial allodynia restricted to the ipsilateral hindpaw. Higher (40-400 microg) doses of zymosan again produce both territorial and extra-territorial allodynia. However, allodynia is now expressed both in the ipsilateral as well as contralateral hindpaws. Several lines of evidence are provided that the appearance of this contralateral ('mirror') allodynia reflects local actions of zymosan on the sciatic nerve rather than spread of this immune activator to the general circulation. Since many clinical neuropathies result from inflammation/infection of peripheral nerves rather than frank physical trauma, understanding how immune activation alters pain processing may suggest novel approaches to pain control.

Sciatic inflammatory neuritis (SIN): behavioral allodynia is paralleled by peri-sciatic proinflammatory cytokine and superoxide production

We have recently developed a model of sciatic inflammatory neuritis (SIN) to assess how immune activation near peripheral nerves influences somatosensory processing. Administration of zymosan (yeast cell walls) around a single sciatic nerve produces dose-dependent low-threshold mechanical allodynia without thermal hyperalgesia. Low (4 microg) doses produce both territorial and extraterritorial allodynia restricted to the injected hindleg. In contrast, higher (40 microg) doses produce territorial and extraterritorial allodynias of both hindlegs, an effect not accounted for by systemic spread of the zymosan. The aim of these experiments was to determine whether these behavioral allodynias were correlated with immunological and/or anatomical changes in or around the sciatic nerve. These experiments reveal that zymosan-induced bilateral allodynia was associated with the following: (a) increased release of both interleukin-1beta and tumor necrosis factor-alpha from peri-sciatic immune cells; (b) increased release of reactive oxygen species from perisciatic immune cells; (c) no change in circulating levels of proinflammatory cytokine; (d) no apparent zymosan-induced influx of immune cells into the sciatic nerve from the endoneurial blood vessels; (e) mild edema of the sciatic, which was predominantly restricted to superficial regions closest to the peri-sciatic immune cells; and (f) no anatomic evidence of changes in either the ipsilateral saphenous nerve or contralateral sciatic nerve that could account for the appearance of extraterritorial or contralateral ("mirror") allodynia, respectively. No reliable differences were found when the low-dose zymosan was compared with vehicle controls. Taken together, these data suggest that substances released by peri-sciatic immune cells may induce changes in the sciatic nerve, leading to the appearance of bilateral allodynia.

Vaccination and autoimmunity-'vaccinosis': a dangerous liaison?

The question of a connection between vaccination and autoimmune illness (or phenomena) is surrounded by controversy. A heated debate is going on regarding the causality between vaccines, such as measles and anti-hepatitis B virus (HBV), and multiple sclerosis (MS). Brain antibodies as well as clinical symptoms have been found in patients vaccinated against those diseases. Other autoimmune illnesses have been associated with vaccinations. Tetanus toxoid, influenza vaccines, polio vaccine, and others, have been related to phenomena ranging from autoantibodies production to full-blown illness (such as rheumatoid arthritis (RA)). Conflicting data exists regarding also the connection between autism and vaccination with measles vaccine. So far only one controlled study of an experimental animal model has been published, in which the possible causal relation between vaccines and autoimmune findings has been examined: in healthy puppies immunized with a variety of commonly given vaccines, a variety of autoantibodies have been documented but no frank autoimmune illness was recorded. The findings could also represent a polyclonal activation (adjuvant reaction). The mechanism (or mechanisms) of autoimmune reactions following immunization has not yet been elucidated. One of the possibilities is molecular mimicry; when a structural similarity exists between some viral antigen (or other component of the vaccine) and a self-antigen. This similarity may be the trigger to the autoimmune reaction. Other possible mechanisms are discussed. Even though the data regarding the relation between vaccination and autoimmune disease is conflicting, it seems that some autoimmune phenomena are clearly related to immunization (e.g. Guillain-Barre syndrome). The issue of the risk of vaccination remains a philosophical one, since to date the advantages of this policy have not been refuted, while the risk for autoimmune disease has not been irrevocably proved. We discuss the pros and cons of this issue (although the temporal relationship (i.e. always 2-3 months following immunization) is impressive).

Ischemic osteonecrosis under fixed partial denture pontics: radiographicand microscopic features in 38 patients with chronic pain

STATEMENT OF PROBLEM

Previous studies have identified focal areas of alveolar tenderness, elevated mucosal temperature, radiographic abnormality, and increased radioisotope uptake or "hot spots" within the quadrant of pain in most patients with chronic, idiopathic facial pain (phantom pain, atypical facial neuralgia, and atypical facial pain).

PURPOSE

This retrospective investigation radiographically and microscopically evaluated intramedullary bone in a certain subset of patients with histories of endodontics, extraction, and fixed partial denture placement in an area of "idiopathic" pain.

MATERIAL AND METHODS

Patients from 12 of the United States were identified through tissue samples, histories, and radiographs submitted to a national biopsy service. Imaging tests, coagulation tests, and microscopic features were reviewed. Of 38 consecutive idiopathic facial pain patients, 32 were women.

RESULTS

Approximately 90% of subpontic bone demonstrated either ischemic osteonecrosis (68%), chronic osteomyelitis (21%), or a combination (11%). More than 84% of the patients had abnormal radiographic changes in subpontic bone, and 5 of 9 (56%) patients who underwent radioisotope bone scan revealed hot spots in the region. Of the 14 patients who had laboratory testing for coagulation disorders, 71% were positive for thrombophilia, hypofibrinolysis, or both (normal: 2% to 7%). Ten pain-free patients with abnormal subpontic bone on radiographs were also reviewed.

CONCLUSIONS

Intraosseous ischemia and chronic inflammation were suggested as a pathoetiologic mechanism for at least some patients with atypical facial pain. These conditions were also offered as an explanation for poor healing of extraction sockets and positive radioisotope scans.

The Guillain-Barré syndrome and the 1992-1993 and 1993-1994 influenza vaccines

BACKGROUND

The number of reports of influenza-vaccine-associated Guillain-Barré syndrome to the national Vaccine Adverse Event Reporting System increased from 37 in 1992-1993 to 74 in 1993-1994, arousing concern about a possible increase in vaccine-associated risk.

METHODS

Patients given a diagnosis of the Guillain-Barré syndrome in the 1992-1993 and 1993-1994 influenza-vaccination seasons were identified in the hospital-discharge data bases of four states. Vaccination histories were obtained by telephone interviews during 1995-1996 and were confirmed by the vaccine providers. Disease with an onset within six weeks after vaccination was defined as vaccine-associated. Vaccine coverage in the population was measured through a random-digit-dialing telephone survey.

RESULTS

We interviewed 180 of 273 adults with the Guillain-Barré syndrome; 15 declined to participate, and the remaining 78 could not be contacted. The vaccine providers confirmed influenza vaccination in the six weeks before the onset of Guillain-Barré syndrome for 19 patients. The relative risk of the Guillain-Barré syndrome associated with vaccination, adjusted for age, sex, and vaccine season, was 1.7 (95 percent confidence interval, 1.0 to 2.8; P=0.04). The adjusted relative risks were 2.0 for the 1992-1993 season (95 percent confidence interval, 1.0 to 4.3) and 1.5 for the 1993-1994 season (95 percent confidence interval, 0.8 to 2.9). In 9 of the 19 vaccine-associated cases, the onset was in the second week after vaccination, all between day 9 and day 12.

CONCLUSIONS

There was no increase in the risk of vaccine-associated Guillain-Barré syndrome from 1992-1993 to 1993-1994. For the two seasons combined, the adjusted relative risk of 1.7 suggests slightly more than one additional case of Guillain-Barré syndrome per million persons vaccinated against influenza.

Isolation and culture of bovine endothelial cells of endoneurial origin

Penetration of immunoglobulins and/or migration of activated lymphocytes into peripheral nervous system (PNS) parenchyma are the initial key steps to develop immunological disorders of PNS including Guillain-Barré syndrome, IgM neuropathy and chronic inflammatory demyelinating polyradiculoneuropathy. Hence, it is important to know the cellular property of endothelial cells of endoneurial tissue origin (PnMEC) because these cells constitute the bulk of the blood-nerve barrier (BNB). For this purpose, we developed a method to isolate and culture pure populations of PnMECs from bovine cauda equina. PnMECs were identified by their cobblestone appearance, immunoreactivity against Factor VIII/von Willebrand factor (vWF) antigen, and positive uptake of DiI-Ac-LDL. The glucose transporter type 1 (GLUT1) expression of these cells was rapidly down-regulated in vitro. Other than GM3(NeuAc) and GM3(NeuGc) as major glycosphingolipids, PnMECs comprise GM1, GD1a, GD1b and GT1b, which are shared by PNS parenchyma, and sialyl lactosaminyl paragloboside (SLPG) as minor species. Because bovine PnMECs proliferate rapidly and a large mass of cells could be obtained, this method should contribute to the biochemical analysis of surface molecules in PnMECs that might play a key role in the formation of BNB as well as in pathological conditions involving the PNS.

Acute idiopathic polyneuropathy in nine cats

This report describes nine unrelated cats with acute idiopathic polyneuropathy. All cats presented with acutely developing tetraparesis or tetraparalysis and loss of spinal reflexes. Seven cats recovered completely within 4 to 6 weeks, without any medication. Two years after complete recovery, none of these cats had had a relapse. In the acute stage, two cats were euthanized because of respiratory complications. Postmortem examination was performed on one of these cats and revealed generalized peripheral motor polyneuropathy. The clinical signs in these cats were identical to those of the Guillain-Barré syndrome in humans.

Local anesthetic effects in the presence of chronic osteomyelitis (necrosis) of the mandible: implications for localizing the etiologic sites of referred trigeminal pain

The aims of this study were: (1) to demonstrate how reproducible variations in incomplete anesthesia of the inferior alveolar nerve can be used as a guide to locate the etiologic sites of referred trigeminal pain emanating from the mandible; (2) to describe the salient histopathologic features of a lowgrade, nonsuppurative osteomyelitis seen in this patient population. Forty-six patients with idiopathic facial pain were subjected to a specific protocol of local anesthetic injections to sequentially block branches of the mandibular nerve to determine the effects on his/her pain. If this significantly reduced or altered the pain on three separate appointments, then exploratory surgery was conducted near identified zones of unanesthetized gingiva. Blocking (92%), bridging (4%), and divergence (4%) were observed patterns of anesthetic resistance of the mucogingival tissues used to categorize the incomplete anesthesia. A 100% correlation was found between the identified zones of unanesthetized gingiva and the discovery of intramedullary pathology. Medullary fibrosis with ischemic and degenerative changes in the cancellous bone were common findings, along with chronic inflammatory cell infiltrates and clusters of lymphocytes. It is concluded that Ratner's method of diagnostic anesthesia be implemented when searching for occult pain producing pathology of the jaws.

Long-term effects of jawbone curettage on the pain of facial neuralgia

PURPOSE

To evaluate the dimension and duration of pain reduction in patients with facial neuralgias after localization, decortication, and curettage of histologically confirmed inflammatory jawbone lesions of the newly identified form of alveolar avascular osteonecrosis called neuralgia-inducing cavitational osteonecrosis (NICO).

MATERIALS AND METHODS

One hundred ninety patients who could be located retrospectively and who had histories of jawbone curettage for chronic "idiopathic" facial pain, either trigeminal neuralgia (TN) or atypical facial neuralgia/pain (AFN), were identified through surgical pathology reports from four institutions. To assess pain reduction after jawbone surgery, these patients were mailed a modified McGill Pain Survey by investigators with whom they had had no previous professional contact. Patient demographics and clinicopathologic characteristics were also reviewed through surgical pathology specimens and reports.

RESULTS

More than two thirds of the respondents to whom the questionnaire was mailed experienced complete or almost complete disappearance of neuralgic pain immediately or shortly after curettage of jawbone osteonecrosis (NICO), regardless of whether they had previously been diagnosed with TN or AFN. Thirty percent, however, experienced local recurrence of jaw inflammation and facial pain, and one third developed at least one and as many as 12 additional foci of histologically confirmed osteonecrosis. Despite this, however, the long-term (average, 4.6 years) abatement of neuralgic pain was total or almost total in 74% of treated patients.

CONCLUSIONS

Neuraglia-inducing cavitational osteonecrosis appears to be associated with at least some cases of facial neuralgia, or with a pain so similar as to be clinically indistinguishable. Decortication and curettage dramatically reduces or eliminates this intense pain in two of every three patients, although multiple surgeries may be required, and additional sites of osteonecrosis may occur. It is recommended that NICO be included in the differential diagnosis of idiopathic facial pain syndromes.