Coronoid process hyperplasia: an unusual cause of mandibular hypomobility

A large number of disorders affecting the masticatory system can cause restriction of mouth opening. The most common conditions related to this problem are those involving the temporomandibular joint (TMJ) and the masticatory muscles, when facial pain also is an usual finding. Congenital or developmental mandibular disorders are also possible causes for mouth opening limitation, although in a very small prevalence. Coronoid process hyperplasia (CPH) is an example of these cases, characterized by an excessive coronoid process growing, where mandibular movements become limited by the impaction of this structure on the posterior portion of the zygomatic bone. This condition is rare, painless, usually bilateral and progressive, affecting mainly men. Diagnosis of CPH is made based on clinical signs of mouth opening limitation together with imaging exams, especially panoramic radiography and computerized tomography (CT). Treatment is exclusively surgical. This paper presents a case of a male patient with bilateral coronoid process hyperplasia, initially diagnosed with bilateral disk displacement without reduction, and successfully treated with intraoral coronoidectomy. It is emphasized the importance of differential diagnosis for a correct diagnosis and, consequently, effective management strategy.

A comparative radiographic investigation of femoroacetabular impingement in young patients with and without hip pain

OBJECTIVE: To compare the existence of radiographic abnormalities in two groups of patients, those with and without hip pain. METHODS: A total 222 patients were evaluated between March 2007 and April 2009; 122 complained of groin pain, and 100 had no symptoms. The individuals in both groups underwent radiographic examinations of the hip using the following views: anteroposterior, Lequesne false profile, Dunn, Dunn 45º, and Ducroquet. RESULTS: A total of 1110 radiographs were evaluated. Female patients were prevalent in both groups (52% symptomatic, 58% asymptomatic). There were statistically significant differences between the groups in age (p<0.0001), weight (p = 0.002) and BMI (p = 0.006). The positive findings in the group with groin pain consisted of the presence of a bump on the femoral head in the anteroposterior view (p<0.0001) or in the Dunn 45º view (p = 0.008). The difference in the a angle in the anteroposterior, Dunn, Dunn 45º, and Ducroquet views for all of the cases studied was p,0.0001. The joint space measurement differed significantly between groups in the Lequesne view (p = 0.007). The Lequesne anteversion angle (ρ) and the femoral offset measurement also differed significantly (p = 0.005 and p = 0.0001, respectively). CONCLUSIONS: We conclude that the best views for diagnosing a femoroacetabular impingement are the anteroposterior pelvic orthostatic, the Dunn 45º, and the Ducroquet views. The following findings correlated with hip pain: a decrease in the femoral offset, an increase in the α angle, an increase in the Lequesne ρ angle, a decrease in the CE angle of Wiberg, a thinner articular space and the presence of a bump on the femoral head-neck transition.

Clinical rearfoot and knee static alignment measurements are not associated with patellofemoral pain syndrome

The aim of the present study was to investigate the association between the patellofemoral pain syndrome and the clinical static measurements: the rearfoot and the Q angles. The design was a cross-sectional, observational, case-control study. We evaluated 77 adults (both genders), 30 participants with patellofemoral pain syndrome, and 47 controls. We measured the rearfoot and Q angles by photogrammetry. Independent t-tests were used to compare outcome continuous measures between groups. Outcome continuous data were also transformed into categorical clinical classifications, in order to verify their statistical association with the dysfunction, and χ2 tests for multiple responses were used. There were no differences between groups for rearfoot angle [mean differences: 0.2º (95%CI -1.4-1.8)] and Q angle [mean differences: -0.3º (95%CI -3.0-2.4). No associations were found between increased rearfoot valgus [Odds Ratio: 1.29 (95%CI 0.51-3.25)], as well as increased Q angle [Odds Ratio: 0.77 (95%CI 0.31-1.93)] and the patellofemoral pain syndrome occurrence. Although widely used in clinical practice and theoretically thought, it cannot be affirmed that increased rearfoot valgus and increased Q angle, when statically measured in relaxed stance, are associated with patellofemoral pain syndrome (PFPS). These measures may have limited applicability in screening of the PFPS development.

Pain in preterm infants: effects of sex, gestational age, and neonatal illness severity

Neonates hospitalized in a neonatal intensive care unit are exposed to many painful and stressful procedures. Biobehavioral pain reactivity in preterm infants during the neonatal period may reflect the capacity of the central nervous system to regulate arousal and neurobiological organization. We review empirical studies on the effects of sex, gestational age, and neonatal illness severity on pain reactivity in children born preterm. A literature search was conducted using PubMed, Institute of Scientific Information Web of Science, PsycINFO, Latin American and Caribbean Health Sciences Literature, and Scientific Electronic Library Online databases. Additionally, a special search was performed in online journals that publish pain studies including Pain, Early Human Development, European Journal of Pain, and Pain Management Nursing. The literature search covered the period from 2004 to 2009. Data were extracted according to predefined inclusion and exclusion criteria. Of the 18 studies reviewed, 16 analyzed gestational age, 13 examined neonatal illness severity, and eight focused on sex. Most of the studies analyzed more than one of these three variables. The majority of the studies found effects of gestational age (n = 14) and neonatal illness severity (n = 11) on pain responses. Only two studies found an influence of sex on infant pain responses. In conclusion, gestational age and neonatal illness severity influence pain responses in infants born preterm. Further studies should be conducted to examine the influence of sex on pain responses.

Temporomandibular disorders and parafunctional oral habits: an anamnestic study

OBJECTIVE: To assess the frequency and severity of the signs and symptoms of temporomandibular disorders (TMD), the frequency of parafunctional oral habits and the correlation between the variables by means of the patients' perception regarding their problem. METHODS: One hundred patients diagnosed with TMD, through a clinical examination of their masticatory system, answered the questions of a previously published protocol concerning the signs and symptoms most frequently reported in the literature. RESULTS: According to the results from the non parametric statistical analysis, the frequency for the following signs and symptoms was significant: Fatigue and muscle pain, joint sounds, tinnitus, ear fullness, headache, chewing impairment and difficulty to yawn (p<0.01) and otalgia (p<0.05). As to the parafunctional oral habits, there was a significant presence of teeth clenching during the day and night (p<0.01) and teeth grinding at night (p<0.05). The variable correlation analysis showed that there was a positive correlation between symptom frequency and severity; age was correlated with the presence of otalgia, cervical pain and teeth sensitivity, besides being correlated with muscle and joint pain severity. Habit frequency was negatively correlated with age. TMD duration was also positively correlated with the symptoms of tinnitus, ear fullness, muscle and joint pain. CONCLUSION: The study results showed that the anamnestic assessment using ProDTMMulti can predict the severity of the TMD case.

Laser therapy and pain-related behavior after injury of the inferior alveolar nerve: possible involvement of neurotrophins

Nerve-related complications have been frequently reported in dental procedures, and a very frequent type of occurrence involves the inferior alveolar nerve (IAN). The nerve injury in humans often results in persistent pain accompanied by allodynia and hyperalgesia. In this investigation, we used an experimental IAN injury in rats, which was induced by a Crile hemostatic clamp, to evaluate the effects of laser therapy on nerve repair. We also studied the nociceptive behavior (von Frey hair test) before and after the injury and the behavioral effects of treatment with laser therapy (emitting a wavelength of 904 nm, output power of 70 Wpk, a spot area of *0.1 cm2, frequency of 9500 Hz, pulse time 60 ns and an energy density of 6 J/cm2). As neurotrophins are essential for the process of nerve regeneration, we used immunoblotting techniques to preliminarily examine the effects of laser therapy on the expression of nerve growth factor (NGF) and brainderived neurotrophic factor (BDNF). The injured animals treated with laser exhibited an improved nociceptive behavior. In irradiated animals, there was an enhanced expression of NGF (53%) and a decreased BDNF expression (40%) after laser therapy. These results indicate that BDNF plays a locally crucial role in pain-related behavior development after IAN injury, increasing after lesions (in parallel to the installation of pain behavior) and decreasing with laser therapy (in parallel to the improvement of pain behavior). On the other hand, NGF probably contributes to the repair of nerve tissue, in addition to improving the pain-related behavior.

Relationship between pain and anxiety in rats

Clinically, it is well known that neuropathic pain often induces comorbid symptoms such as anxiety. In turn, also anxiety has been associated with a heightened experience of pain. Although, the link between pain and anxiety is well recognized in humans, the neurobiological basis of this relationship remains unclear. Therefore, the aim of the current study was to investigate the influence of neuropathic pain on anxiety and vice versa in rats by assessing not only pain-related behaviour but also by discovering possible key substrates which are responsible for the interrelation of pain and anxiety.rnIn rats with a chronic constriction of the sciatic nerve (CCI model) anxiety-like behaviour was observed. Since anxiety behaviour could be completely abolished after the treatment of the pure analgesic drugs gabapentin and morphine, we concluded that anxiety was caused by the strong persistent pain. Furthermore, we found that the neuropeptides oxytocin and vasopressin were upregulated in the amygdala of CCI rats, and the intra-amygdala treatment of an oxytocin antagonist but not the vasopressin antagonist could reduce anxiety-like behaviour in these animals, while no effect on mechanical hypersensitivity was observed. These data indicate that oxytocin is implicated in the underlying neuronal processes of pain-induced anxiety and helps to elucidate the pathophysiological mechanisms of neuropathic pain. rnTo assess the influence of trait anxiety on pain sensation in rats, we determined mechanical hypersensitivity after sciatic nerve lesion (CCI) in animals selectively bred for high anxiety or low anxiety behaviour. The paw withdrawal thresholds were significantly decreased in high anxiety animals in comparison to low anxiety animals 2 and 3 weeks after surgery. In a second model state anxiety was induced by the sub-chronic injection of the anxiogenic drug pentylentetrazol in naive rats. Pain response to mechanical stimuli was increased after pharmacologically-induced anxiety. These results provided evidence for the influence of both trait and state anxiety on pain sensation. rnThe studies contribute to the elucidation of the relationship between pain and anxiety. We investigated that the neuropathic pain model displays sensory as well as emotional factors of peripheral neuropathy. Changes in expression levels of neuropeptides in the central nervous system due to neuropathic pain may contribute to the pathophysiology of neuropathic pain and its related symptoms in animals which might also be relevant for human scenarios. The results of the current study also confirm that anxiety plays an important role in the perception of pain. rnA better understanding of pain behaviour in animals might improve the preclinical profiling of analgesic drugs during development. The study highlights the potential use of the rat model as a new preclinical tool to further investigate the link between pain and anxiety by determining not only the sensory reflexes after painful stimuli but also the more complex pain-related behaviour such as anxiety.rn

Biomedicine and pain

The focus of my research is on contemporary biomedical construction of pain as an object, i.e. the different ways in which pain has been conceptualized and approached as a specific site of investigation in biomedicine. A significant shift in the scientific conception of pain occured in the second half of XXth century. In 1965, Ronald Melzack and Patrick D. Wall propose the Gate Control theory of pain mechanism. This theory denies a fixed and direct relationship between stimulus and pain perception, and emphazises the role played by psychological factors in pain. The IASP utilizes this perspective on the phenomenon, describing pain as “an unpleasant sensory and emotional experience associated to an actual or potential tissue damage or described in the terms of such a damage.” The relationship between pain and damage is pivotal in the definition of pain as a pathological entity. In particular, the biomedical approach to pain appears to be strongly characterized by a dualistic view of its aetiology. Disease conceptions such as “psychogenic pain” and chronic pain are deeply influenced by the ways in which psychological factors have been interpreted as components, or as causes of pain. In the second part of my dissertation, I focus on fibromyalgia, which is emblematic of the problematic acknowledgment of chronic pain as a disease. Even if fibromyalgia is actually treated in Rheumatology, its status as a disease is blurred, mainly because of its complex symptomatology including both physiological manifestations and psychological ones. In the conclusion, I present a scenario of the different ways in which this disease is dealt with in biomedical knowledge, through medical literature, clinical practice, and patients’ accounts. The findings of an ethnographic enquiry in the Rheumatology Division of a local clinic and a visual research on patients’ experiences are analyzed and discussed.

Involvement of the opioid system and BDNF in neuroplastic alterations occurring in neuropathic pain conditions

Chronic pain affects one in five adults, reducing quality of life and increasing risk of developing co-morbidities such as depression. Neuropathic pain results by lesions to the nervous system that alter its structure and function leading to spontaneous pain and amplified responses to noxious and innocuous stimuli. The Opioid System is probably the most important system involved in control of nociceptive transmission. Dynorphin and nociceptin systems have been suggested key mediators of some neuropathic pain aspects. An important role also for BDNF has been recently suggested since its involvement in the peripheral and central sensitization phenomena is known. We studied neuroplastic alterations occurring in chronic pain in mice subjected to the chronic constriction injury (CCI). We investigated gene expression alterations of both BDNF and Opioid System at spinal level at different intervals of time. A transient upregulation of pBDNF and pDYN was observed in spinal cord, while increasing upregulation of ppN/OFQ was found in the DRGs of injured mice. Development of neuropathic behavioral signs has been observed in ICR/CD-1 and BDNF+/+ mice, subjected to CCI. A different development of these signs was observed in BDNF+/-. We also studied gene expression changes of investigated systems in different brain areas fourteen days after surgery. We found pBDNF, pDYN, pKOP, ppN/OFQ and pNOP gene expression alterations in several areas of CCI mice. In the same brain regions we also determined bioactive nociceptin peptide levels, and elevated N/OFQ levels were observed in the amygdala area. Histone modifications studies have been performed in BDNF and DYN gene promoters of CCI animal spinal cord showing selected alterations in pDYN gene promoter. In addition, a preliminary characterization of the innovative NOP-EGFP mice was performed. Overall, our results could be useful to understand which and how neuropeptidergic systems are involved in neuroplastic mechanism occurring in neuropathic pain.

PPAR-gamma expression in peritoneal endometriotic lesions correlates with pain experienced by patients

Endometriosis is a significant gynecologic condition that can cause both pain and infertility and affects up to 15% of women during their reproductive years. In peritoneal endometriotic lesions, the expression of peroxisome proliferation-activated receptor gamma, a nuclear receptor with antiinflammatory and neuroprotective roles, is positively correlated with the pain reported by patients.

MicroRNAs may mediate the down-regulation of neurokinin-1 receptor in chronic bladder pain syndrome

Bladder pain syndrome (BPS) is a clinical syndrome of pelvic pain and urinary urgency-frequency in the absence of a specific cause. Investigating the expression levels of genes involved in the regulation of epithelial permeability, bladder contractility, and inflammation, we show that neurokinin (NK)1 and NK2 tachykinin receptors were significantly down-regulated in BPS patients. Tight junction proteins zona occludens-1, junctional adherins molecule -1, and occludin were similarly down-regulated, implicating increased urothelial permeability, whereas bradykinin B(1) receptor, cannabinoid receptor CB1 and muscarinic receptors M3-M5 were up-regulated. Using cell-based models, we show that prolonged exposure of NK1R to substance P caused a decrease of NK1R mRNA levels and a concomitant increase of regulatory micro(mi)RNAs miR-449b and miR-500. In the biopsies of BPS patients, the same miRNAs were significantly increased, suggesting that BPS promotes an attenuation of NK1R synthesis via activation of specific miRNAs. We confirm this hypothesis by identifying 31 differentially expressed miRNAs in BPS patients and demonstrate a direct correlation between miR-449b, miR-500, miR-328, and miR-320 and a down-regulation of NK1R mRNA and/or protein levels. Our findings further the knowledge of the molecular mechanisms of BPS, and have relevance for other clinical conditions involving the NK1 receptor.

An fMRI study on mental pain and suicidal behavior

Suicide is a poorly understood phenomenon. A clinical model of suicide conceptualizes suicidal behavior as a solution to an unbearable state of mind, experienced as mental pain.