Effects of Dry Needling on Active Myofascial Trigger Points and Pain Intensity in Tension-Type Headache: A Randomized Controlled Study

Tension-type headache is the most prevalent type of headache and is commonly associated with myofascial pain syndrome and the presence of active myofascial trigger points. This randomized controlled trial aimed to assess the impact of dry needling on the total number of active trigger points, pain intensity, and perceived clinical change in tension-type headache subjects. Thirty-two subjects were randomly assigned to the control and dry needling groups. The presence of active trigger points in 15 head and neck muscles, the headache intensity, and the perceived clinical change were evaluated. A single dry needling technique was administered at each active trigger point across three sessions. Significant differences were observed in the post-treatment measures favouring the dry needling group, including reductions in the headache intensity scores (p = 0.034) and the total number of active trigger points (p = 0.039). Moreover, significant differences in the perception of clinical change were found between the control and treatment groups (p = 0.000). Dry needling demonstrated positive effects in reducing the number of active trigger points and improving the short-term headache intensity in tension-type headache patients. A single dry needling session applied in the cranio-cervical area resulted in a self-perceived improvement compared to the control subjects.

Sex differences in visceral sensitivity and brain activity in a rat model of comorbid pain: a longitudinal study

ABSTRACT

Temporomandibular disorder (TMD) and irritable bowel syndrome (IBS) are 2 chronic overlapping pain conditions (COPCs) that present with significant comorbidity. Both conditions are more prevalent in women and are exacerbated by stress. While peripheral mechanisms might contribute to pain hypersensitivity for each individual condition, mechanisms underlying the comorbidity are poorly understood, complicating pain management when multiple conditions are involved. In this study, longitudinal behavioral and functional MRI-based brain changes have been identified in an animal model of TMD-like pain (masseter muscle inflammation followed by stress) that induces de novo IBS-like comorbid visceral pain hypersensitivity in rats. In particular, data indicate that increased activity in the insula and regions of the reward and limbic systems are associated with more pronounced and longer-lasting visceral pain behaviors in female rats, while the faster pain resolution in male rats may be due to increased activity in descending pain inhibitory pathways. These findings suggest the critical role of brain mechanisms in chronic pain conditions and that sex may be a risk factor of developing COPCs.

Common differential diagnosis of low back pain in contemporary medical practice: a narrative review

With a wide range of etiologies, low back pain (LBP) presents a true clinical challenge, finding its origins both in intrinsic spinal and systemic conditions, as well as referred ones. This review categorizes the LBP into these three groups and aims to offer a comprehensive look at the tools required to diagnose and differentiate them. The intrinsic etiologies are based on conditions that affect the musculoskeletal components of the lumbar spine, such as intervertebral disc disease, stenosis, muscular imbalance, and facet joint degeneration. The systemic causes usually extend beyond local structures. Such are the cases of neoplasia, infections, and chronic inflammation. The diagnosis is rendered even more complex by adding the referred pain, which only manifests in the lower back yet arises in more distant locations. By synthesizing the literature that encompasses the problem, this review aims to augment the understanding of the differential diagnoses of LBP by showcasing the subject's nuances. This categorization provides a structured approach to a patient-centered diagnosis, which could facilitate the medical practitioners' efforts to navigate this pathology more effectively.

Can Myofascial Trigger Points Involve Nociplastic Pain? A Scoping Review on Animal Models

Nociplastic pain is a non-specific, regional pain lasting more than three months, characterised by the onset of hypersensitivity, despite no clear evidence of tissue damage. It is a relatively new classified type of pain. As a result, there has not yet been much work describing its precise modelling. The mechanism of its formation needs to be clearly explained. Authors point out that the occurrence of myofascial trigger points (MTrPs) can lead to this type of pain as one possibility. This paper summarises the available literature on modelling nociplastic pain and MTrPs. It complies with studies describing animal model creation and presents the results of performed experiments. The literature search was conducted in December 2022 and included the following databases: PubMed, Scopus, and Web of Science. In this scoping review, six studies were included. Two described the creation of animal models of nociplastic pain, one adapted old models to nociplastic pain, and three described the modelling of MTrPs. This is the first paper pointing in the possible direction of detecting and studying the correlation between MTrPs and nociplastic pain in animal models. However, there is currently insufficient evidence to describe MTrPs as nociplastic, as few studies with animal models exist.

Severe Referred Shoulder Pain Following Revision Fundoplication From a Stich on the Diaphragm

Complications following fundoplication surgery for hiatal hernias are rare. Herein, we present the case of a 61-year-old woman who underwent a Nissen fundoplication, complicated by dysphagia, and a revision modified Toupet fundoplication for a hiatal hernia, after which she began to experience severe prandial referred left shoulder pain that was refractory to medical management. We hypothesized that a diaphragmatic suture placed during the revision fundoplication could be the source of the pain, and we elected to remove the suture, resulting in resolution of the pain. This pain remained resolved at the most recent follow-up on postoperative week six, and the patient had no further concerns.

Posterior Communicating Artery Aneurysm With Referred Tooth Pain: A Case Report

Oculomotor nerve (CN III) palsy (ONP) has multiple etiologies, with aneurysms and ischemic injury being the two leading causes. The presentations of these conditions differ, as aneurysms commonly manifest with pupillary involvement, while ischemic-related ONP often leads to a pupil-sparing presentation. We present a 63-year-old African American male with a history of sickle cell trait, ocular sickle cell disease, and untreated hypertension that develops "down and out" left eye with a mid-dilated pupil unresponsive to light. However, the patient developed severe left upper tooth pain after the onset of the eye pain, which progressed to ONP. The patient's dental and radiographic evaluation did not indicate any obvious source for his tooth pain. Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) of the head revealed a 7-mm saccular aneurysm with a 2-mm neck arising from the left posterior communicating artery (PCOM) aneurysm, and neurovascular surgical intervention was initiated. This case highlights the potential of referred tooth pain as an early symptom in patients with PCOM aneurysm, which physicians should be vigilant about and consider as a potential indicator of the condition. Therefore, collaboration between different specialties, including ophthalmology, neurology, neurosurgery, and dental care, is necessary to formulate a comprehensive treatment plan that effectively addresses the patient's specific needs and challenges.

Sympathetic-Sensory Coupling as a Potential Mechanism for Acupoints Sensitization

A series of studies have demonstrated acupoint sensitization, in which acupoints can be activated in combination with sensory hypersensitivity and functional plasticity during visceral disorders. However, the mechanisms of acupoint sensitization remain unclear. Neuroanatomy evidence showed nociceptors innervated in acupoints contribute to the mechanism of acupoint sensitization. Increasing studies suggested sympathetic nerve plays a key role in modulating sensory transmission by sprouting or coupling with sensory neuron/nociceptor in the peripheral, forming the functional structure of the sympathetic-sensory coupling. Notably, the sensory inputs of the disease-induced sensitized acupoint contribute to the homeostatic regulation and also involve in delivering therapeutic information under acupuncture, hence, the role of sprouted sympathetic in acupoint function should be given attention. We herein reviewed the current knowledge of sympathetic and its sprouting in pain modulation, then discussed and highlighted the potential value of sympathetic-sensory coupling in acupoint functional plasticity.

Referred pain: characteristics, possible mechanisms, and clinical management

Purpose of this review

Referred pain is a common but less understood symptom that originates from somatic tissues. A comprehensive recognition of referred pain is important for clinicians when dealing with it. The purpose of this study is to summarize the current understanding of referred pain, including its pathogenesis, characteristics, diagnosis, and treatment.

Recent findings

Referred pain arises not only from pathologies primarily involving local tissue but also from lesions in distant structures. Central sensitization of convergent neurons and peripheral reflexes of dichotomizing afferent fibers are two theories proposed to explain the pathological mechanism of referred pain. Because syndromes related to referred pain of different origins overlap each other, it is challenging to define referred pain and identify its originating lesions. Although various approaches have been used in the diagnosis and treatment of referred pain, including conservative treatment, blockade, radiofrequency, and surgery, management of referred pain remains a clinical challenge.

Summary

Unlike radicular pain and neuropathic pain, referred pain is a less studied area, despite being common in clinics. Referred pain can derive from various spinal structures, and blockage helps identify the primary pathology. Due to the heterogeneity of referred pain, treatment outcomes remain uncertain. Further studies are needed to improve our understanding of referred pain.

Point-of-care ultrasound-assisted diagnosis of gastric vessel rupture in a young man presenting with chest pain: A cautionary tale

We report a young male patient who presented with chest and shoulder tip pain with spontaneous intraperitoneal haemorrhage (haemoperitoneum) due to gastric vessel rupture. Point-of-care ultrasound detected abdominal free fluid, which led to a CT scan of the abdomen and reached the diagnosis. Intra-abdominal bleeding can present as referred chest or shoulder tip pain, as more commonly seen in females with pelvic pathologies. Point-of-care ultrasound may add diagnostic value with the detection of a haemoperitoneum in this context.

A Pain That is Easily Overlooked: Referred Pain Caused by OVCF

Purpose

The objective of this study was to analyze the clinical characteristics and the therapeutic effects of treatment at our spinal center in OVCF patients associated with referred pain. The underlying goals were to deepen the understanding of referred pain caused by OVCFs, improve the currently low early diagnosis rate of OVCFs, and improve the effectiveness of treatment.

Methods

The patients who had referred pain from OVCFs and met the inclusion criteria were retrospectively analyzed. All patients were treated with percutaneous kyphoplasty (PKP). Visual analog scale (VAS) scores and Oswestry Disability Index (ODI) were used to evaluate the therapeutic effect at different time points.

Results

There were 11 males (19.6%) and 45 females (80.4%). Their corresponding mean bone mineral density (BMD) value was -3.3 ± 0.4. The regression coefficient of BMD in the linear regression equation was -4.51 (P<0.001). According to the classification system for referred pain in OVCFs, there were 27 cases of type A (48.2%), 12 cases of type B (21.2%), 8 cases of type C (14.3%), 3 cases of type D (5.4%), and 6 cases of type E (10.7%). All patients were followed up for at least 6 months, and both VAS scores and ODI were found to be significantly better postoperatively than preoperatively (P<0.001). There was no significant difference in VAS scores and ODI between different types preoperatively or 6 months postoperatively (P > 0.05). Within each type, there were significant differences in VAS scores and ODI between the pre- and postoperative timepoints (P < 0.05).

Conclusion

Attention should be paid to referred pain in OVCF patients, which is not uncommon in clinical practice. Our summary of the characteristics of referred pain caused by OVCFs can improve the early diagnosis rate of OVCFs patients and provide a reference for their prognosis after PKP.

Modulation of Central Nociceptive Transmission by Manual Pressure Techniques in Patients with Migraine: An Observational Study

Background: Manual pressure in the upper cervical spine is used to provoke and reduce the familiar migraine headache. Information is scarce on the segmental levels, myofascial structure provocation, and reduction occurrences. The required dosage (amount of pressure, number of repetitions, and duration) has not been objectified yet. Methods: Prospective observational study. Thirty patients with migraine were examined interictally. Manual pressure was applied at four sites: the posterior arch of C1, the articular pillar of C2, the rectus capitis posterior major muscle, and the obliquus capitis inferior muscle, bilaterally. On sites where the familiar headache was provoked, the pressure was sustained to induce pain reduction (three repetitions). Provocation of familiar headache (yes/no), headache intensity (numerical pain rating scale), time to obtain a reduction of the headache (seconds), and applied pressure (g/cm2) were recorded. Results: Provocation of the familiar headache occurred at the posterior arches C1 in 92%, and at one of the articular pillars of C2 in 65.3% of cases. At one of the rectus capitis major muscles, the familiar headache was provoked in 84.6% of cases; at one of the oblique capitis inferior muscles, the familiar headache was provoked in 76.9% of cases. The applied mean pressure ranged from 0.82 to 1.2 kg/cm2. Maintaining the pressure reduced headache pain intensity significantly between the start and end of each of the three consecutive trials (p < 0.04). This reduction occurred faster in the third application than in the first application (p = 0.03). Conclusion: Manual pressure at upper cervical segments provokes familiar referred migraine headaches, with low manual pressure. Maintaining the pressure reduces the referred head pain significantly, indicating modulation of central nociceptive transmission.

We Should Pay Attention to "Referred Pain" - A Case of Acute Myocardial Infarction That Masked and Delayed the Diagnosis of Esophageal Perforation

We herein report a 93-year-old woman diagnosed with acute myocardial infarction (AMI) based on typical laboratory findings of severe chest pain accompanied by throat pain. This condition was initially interpreted as referred pain of cardiac origin. However, the patient had persistent throat pain after successful percutaneous coronary intervention. Upper esophageal perforation with life-threatening acute mediastinitis was unexpectedly identified by a further examination. Clinicians should have a high index of suspicion in cases with persistent symptoms thought to be referred pain among AMI patients, as these symptoms may not be of cardiac origin but rather a sign of another concomitant critical disease.

Somatovisceral Convergence in Sleep-Wake Cycle: Transmitting Different Types of Information via the Same Pathway

Convergence of somatic and visceral inputs occurs at the levels of nervous system ranging from spinal cord to cerebral cortex. This anatomical organization gave explanation to a referred pain phenomenon. However, it also presents a problem: How does the brain know what information is coming for processing-somatic or visceral - if both are transferred by the same spinal cord fibers by means of the standard neuronal spikes? Recent studies provided evidence for cortical processing of interoceptive information largely occurring in sleep, when somatosensation is suppressed, and for the corresponding functional brain networks rearrangement. We suggest that convergent units of the spinal cord would be able to collectively provide mainly somatosensory information in wakefulness and mainly visceral in sleep, solving the puzzle of somatovisceral convergence. We recorded spiking activity from the spinal cord lemniscus pathway during multiple sleep-wake cycles in freely behaving rabbits. In wakefulness high increased spiking corresponded to movements. When animals stopped moving this activity ceased, the fibers remained silent during passive wakefulness. However, upon transition to sleep fibers began firing again. Analysis of spiking patterns of individual fibers revealed that in the majority of them spiking rates recovered in slow wave sleep. Thus, despite cessation of motion and a corresponding decrease of somatic component of the convergent signal, considerable ascending signaling occurs during sleep, that is likely to be visceral. We also recorded evoked responses of the lemniscus pathway to innocuous electrostimulation of the abdominal viscera, and uncovered the existence of two groups of responses depending upon the state of vigilance. Response from an individual fiber could be detected either during wakefulness or in sleep, but not in both states. Wakefulness-responsive group had lower spiking rates in wakefulness and almost stopped spiking in sleep. Sleep-responsive retained substantial spiking during sleep. These groups also differed in spike amplitudes, indicative of fiber diameter differences; however, both had somatic responses during wakefulness. We suggest a mechanism that utilizes differences in somatic and visceral activities to extract both types of information by varying transmission thresholds, and discuss the implications of this mechanism on functional networks under normal and pathological conditions.

Accuracy of Physical Assessment in Nursing for Cervical Spine Joint Pain and Stiffness: Pilot Study Protocol

Background

Cervical spine dysfunction is a condition with high personal, social, and economic impact worldwide. Although its etiology is described as multifactorial, there is a need for further clarification. The literature has demonstrated the anatomical, physiological, and pathophysiological relationship among the cervical spine, temporomandibular joint, and visceral system. To guide and contribute to the accuracy of the physical assessment performed by nurses, we will study the influence of the stomatognathic system and viscerosomatic reflexes on pain and joint stiffness of the cervical spine.

Objective

The aim of this study is to describe a pilot study protocol to investigate the influence of the stomatognathic system and viscerosomatic reflexes on cervical structures.

Methods

A pilot study with a quasi-experimental design was conducted with 50 volunteers from the university population of the Universidade Católica Portuguesa-Porto. We studied the influence of changes in the usual intercuspation, the occlusal deprogramming, and the pressure stimulus of the reflex skin region of the ilium/colon in the cervical spine. This study was divided into 2 phases. In the first phase, we performed the kinematic and pain analysis during the passive mobilization of the upper cervical spine using the Motion Capture System at the Motion Capture Laboratory at UCP-Porto and the Visual Analog Scale. In the second phase, we evaluated the pain threshold on palpation of the erector neck muscles and the structures of the stomatognathic system using algometry. The influence of viscerosomatic reflexes on the structures of the stomatognathic system was also analyzed.

Results

Selection and preparation of the data collection site, acquisition of materials, constitution of the sample group and data collection were completed. The analysis of the results is being carried out.

Conclusions

The data from this study will allow for the detection of the possible influence of the stomatognathic system and viscerosomatic reflexes on pain and range of motion of the upper cervical spine, providing data for future randomized studies. We have also identified potential limitations of this study.

International Registered Report Identifier (IRRID)

RR1-10.2196/31878

Differential Activation of Colonic Afferents and Dorsal Horn Neurons Underlie Stress-Induced and Comorbid Visceral Hypersensitivity in Female Rats

Chronic Overlapping Pain Conditions, including irritable bowel syndrome (IBS) and temporomandibular disorder (TMD), represent a group of idiopathic pain conditions that likely have peripheral and central mechanisms contributing to their pathology, but are poorly understood. These conditions are exacerbated by stress and have a female predominance. The presence of one condition predicts the presence or development of additional conditions, making this a significant pain management problem. The current study was designed to determine if the duration and magnitude of peripheral sensitization and spinal central sensitization differs between restraint stress-induced visceral hypersensitivity (SIH) and chronic comorbid pain hypersensitivity (CPH; stress during pre-existing orofacial pain). SIH in female rats, as determined by the visceromotor response, persisted at least four but resolved by seven weeks. In contrast, CPH persisted at least seven weeks. Surprisingly, colonic afferents in both SIH and CPH rats were sensitized at seven weeks. CPH rats also had referred pain through seven weeks, but locally anesthetizing the colon only attenuated the referred pain through four weeks, suggesting a transition to colonic afferent independent central sensitization. Different phenotypes of dorsal horn neurons were sensitized in the CPH rats seven weeks post stress compared to four weeks or SIH rats. The current study suggests differential processing of colonic afferent input to the lumbosacral spinal cord contributes to visceral hypersensitivity during comorbid chronic pain conditions. PERSPECTIVE: Chronic Overlapping Pain Conditions represent a unique challenge in pain management. The diverse nature of peripheral organs hinders a clear understanding of underlying mechanisms accounting for the comorbidity. This study highlights a mismatch between the condition-dependent behavior and peripheral and spinal mechanisms that contribute to visceral pain hypersensitivity.

Lateralization and Bodily Patterns of Segmental Signs and Spontaneous Pain in Acute Visceral Disease: Observational Study

Background

The differential diagnosis of acute visceral diseases is a challenging clinical problem. Older literature suggests that patients with acute visceral problems show segmental signs such as hyperalgesia, skin resistance, or muscular defense as manifestations of referred visceral pain in somatic or visceral tissues with overlapping segmental innervation. According to these sources, the lateralization and segmental distribution of such signs may be used for differential diagnosis. Segmental signs and symptoms may be accompanied by spontaneous (visceral) pain, which, however, shows a nonsegmental distribution.

Objective

This study aimed to investigate the lateralization (ie, localization on one side of the body, in preference to the other) and segmental distribution (ie, surface ratio of the affected segments) of spontaneous pain and (referred) segmental signs in acute visceral diseases using digital pain drawing technology.

Methods

We recruited 208 emergency room patients that were presenting for acute medical problems considered by triage as related to internal organ disease. All patients underwent a structured 10-minute bodily examination to test for various segmental signs and spontaneous visceral pain. They were further asked their segmental symptoms such as nausea, meteorism, and urinary retention. We collected spontaneous pain and segmental signs as digital drawings and segmental symptoms as binary values on a tablet PC. After the final diagnosis, patients were divided into groups according to the organ affected. Using statistical image analysis, we calculated mean distributions of pain and segmental signs for the heart, lungs, stomach, liver/gallbladder, and kidneys/ureters, analyzing the segmental distribution of these signs and the lateralization.

Results

Of the 208 recruited patients, 110 (52.9%) were later diagnosed with a single-organ problem. These recruited patients had a mean age of 57.3 (SD 17.2) years, and 40.9% (85/208) were female. Of these 110 patients, 85 (77.3%) reported spontaneous visceral pain. Of the 110, 81 (73.6%) had at least 1 segmental sign, and the most frequent signs were hyperalgesia (46/81, 57%), and muscle resistance (39/81, 48%). While pain was distributed along the body midline, segmental signs for the heart, stomach, and liver/gallbladder appeared mostly ipsilateral to the affected organ. An unexpectedly high number of patients (37/110, 33.6%) further showed ipsilateral mydriasis.

Conclusions

This study underlines the usefulness of including digitally recorded segmental signs in bodily examinations of patients with acute medical problems.

Referred Orofacial Pain as an Initial Symptom of Distant, Nonmetastatic Cancer: Report of a Case and Review of the Literature

Referred orofacial pain as the first symptom of an otherwise silent distant, nonmetastatic cancer has been reported, but there is sparse literature on the subject. Referred pain may not be considered in the orofacial pain differential diagnosis because of its rarity; however, this may delay a cancer diagnosis. The authors present a case report and a review of the English literature. Peer-reviewed publications were identified through a systematic search of MEDLINE, Embase, and Cochrane CENTRAL. Historic cases were reviewed, and available data regarding demographics, pain characteristics, treatment, cancer diagnosis, and outcome were extracted. Thirty-seven cases were identified. All cancers were intrathoracic. The average age was 54.1 years with a slight female predominance (3:2). Common pain characteristics were (1) diffuse location affecting the ear (76%), jaw (46%), and temple (30%); (2) constant duration (65%); (3) aching quality (74%); (4) severe intensity (94%); and (5) associated systemic symptoms (68%) such as weight loss and digital clubbing. The average time from the onset of facial pain to seeking medical attention was 9 months, and the average time from seeking medication attention to cancer diagnosis was 8 months. Orofacial pain was often attributed to odontogenic (35%) or neuropathic (25%) causes, and treatments for these conditions were also common. The impact of referred orofacial pain on the cancer prognosis was not possible because of the nature of the reviewed studies (case reports with no comparison group). Cancer-associated referred orofacial pain as a first symptom is rare but should be considered in cases with intractable pain and associated systemic symptoms.

[Essence of acupoints and meridians based on the studies of myofascial trigger points]

Based on the modern anatomy and physiology, the referred pain of myofascial trigger points of each muscle is integrated; compared with the twelve meridians as well as conception vessel and governor vessel, the similarity of their position and running course is observed. With the current research progress of myofascial trigger points and fasciology, based on the running course of referred pain of trigger points, combined with fascia mechanics, nerve and vascular, the location of acupoints and meridians, as well as the relationship between acupoints and meridians, are discussed.

Mechanically Supporting Uterosacral Ligaments for the Relief of Provoked Vulvodynia: A Randomized Pilot Trial

Purpose

Provoked vulvodynia (PV) is the most common cause of vulvar pain and dyspareunia. Although its etiology is unknown, it has been associated with musculoskeletal dysfunction. The inability of the lax uterosacral ligaments (USLs) to support the adjoining T11/L2 and S2-4 nerve plexuses is considered to cause PV. This study aimed to determine whether providing mechanical support to the USLs would improve PV.

Patients and Methods

PV patients were randomly divided into two groups. The participants in each group underwent sham manipulation (inserting a wide swab in the vagina without applying pressure) and trial manipulation (supporting the posterior fornix with a wide swab sufficiently broad to mechanically support the USLs). This was a cross-over trial, and the participants alternated between the sham and trial manipulation. Using a 0-10 visual analog pain scale (VAS), PV-associated pain levels experienced by participants were recorded during each manipulation, and the results were compared with baseline levels.

Results

The pain level significantly reduced with USL support compared with the baseline value and the sham manipulation pain level (P = 0.003). Pain during sham manipulation was not significantly different from that recorded at baseline. The average reduction in pain with USL support was 18.4% ± 2.2%. The manipulation order did not affect changes in the pain level during trial manipulation (P = 0.512).

Conclusion

Applying mechanical support to the posterior fornix temporarily alleviates provoked vulvar pain in some women.

Missed Diagnosis of Cholangiocarcinoma Presenting with Atypical Symptoms

We report a case of delayed diagnosis of cholangiocarcinoma. A 62-year-old man developed acute abdominal pain in multiple sites. As the distribution pattern of the abdominal pain was not correctly interpreted based on the mechanisms of visceral and referred pain, the patient was not investigated with the best diagnostic test at first presentation. Moreover, miscommunication between physicians in a clinic and separate hospital delayed diagnosis. For prompt diagnosis, physicians should be practice careful reasoning and focus on good communication with physicians outside their hospital.

LEARNING POINTS

Abdominal pain without jaundice can be an initial symptom in patients with cholangiocarcinoma.Cholangiocarcinoma in the lower common bile duct can present as lower abdominal pain referred through the 7th-11th thoracic nerves.Physicians can determine the origin of abdominal pain through correct interpretation of the distribution pattern of abdominal pain based on knowledge of pathophysiology.

Diverticulitis in the sigmoid colon presenting with only lower anterior chest pain

An 80-year-old man who presented with only lower anterior chest pain was diagnosed as sigmoid colon diverticulitis. His chest pain was considered to be referred pain from a disease at sigmoid colon, which should be suspected when other major causes of chest pain are excluded.

Schwannoma of the lumbar spine, presenting with pain of the knee, like an osteoid osteoma, in a 10-year-old girl

Localized pain in the absence of local lesion may represent referred pain from the spine, in a child, arising from a benign spinal schwannoma. It can be diagnosed by MRI. Surgical excision of the tumor relieves the symptoms.

Diagnosis and treatment considerations of atypical oral pain in tuberous sclerosis

Diagnosis and management of non-specific, atypical, and non-dental pain are challenging. We hereby report a case of a 23-year-old female who presented with a complaint of intermittent dull ache over her lower front anterior teeth with no radiographic findings. She was diagnosed after history, imaging, and neurology consultation and treated conservatively with complete remission of symptoms. Proper history and counseling are mandatory for all patients. It is important to recognize patients with underlying neurological conditions and take adequate interdepartmental consultation before labeling complaints psychogenic or carrying out unwarranted dental treatment.

The receptive field for visceral pain referred orofacially by the vagus nerves

BACKGROUND

The nociceptive receptive field of the vagus nerves in animals includes virtually the entire thoracic, abdominal and laryngopharyngeal regions. However, the role of the vagus nerves in the transmission of visceral pain in humans, with the exception of pain from coronary artery diseases, is believed to be insignificant.

AIM

The purpose of this report is to map out the clinical visceral pain receptive field of the vagus nerves relative to its nociceptive counterpart in animals.

MATERIALS AND METHODS

The PubMed database and PMC were searched for case reports of patients with orofacial pain believed by the author(s) of the article to be referred from underlying non-cardiac thoracic, laryngopharyngeal or abdominal diseases. Reports of diseases for which non-neural explanations for the orofacial spread of pain were suggested were excluded.

RESULTS

A total of 52 case reports of jaw pain and/or otalgia referred from laryngopharyngeal and noncardiac thoracic sources were discovered. In addition, a multicenter prospective study found that 25.8% of more than 3,000 patients with thoracic aortic dissection experienced pain in the head and neck region. In stark contrast, no case reports of orofacially referred pain from abdominal diseases were found.

DISCUSSION

The results indicate that the laryngopharyngeal and thoracic portions of the vagal receptive field are capable of referring pain orofacially while the abdominal portion is not. The roles of the somatotopic organization of the trigeminal sub nucleus caudalis and neuromodulation in this referral of pain were discussed.

CONCLUSION

Referred orofacial pain can lead to delayed diagnosis and poorer outcome in visceral diseases.

Viscero-visceral hyperalgesia in dysmenorrhoea plus previous urinary calculosis: Role of myofascial trigger points and their injection treatment in the referred area

BACKGROUND

Women with dysmenorrhoea plus symptomatic urinary calculosis experience enhanced pain and referred muscle hyperalgesia from both conditions than women with one condition only (viscero-visceral hyperalgesia). The study aimed at verifying if enhanced dysmenorrhoea persists after urinary stone elimination in comorbid women and if local anaesthetic inactivation of myofascial trigger points (TrPs) in the lumbar area (of urinary pain referral) also relieves dysmenorrhoea.

METHODS

Thirty-one women with dysmenorrhoea plus previous urinary calculosis (Dys+PrCal) and lumbar TrPs, and 33 women with dysmenorrhoea without calculosis (Dys) underwent a 1-year assessment of menstrual pain and muscle hyperalgesia in the uterus-referred area (electrical pain threshold measurement in rectus abdominis, compared with thresholds of 33 healthy controls). At the end of the year, 16 comorbid patients underwent inactivation of TrPs through anaesthetic injections, whereas the remaining 12 received no TrP treatment. Both groups were monitored for another year at the end of which thresholds were re-measured.

RESULTS

In year1, Dys+PrCal presented significantly more painful menstrual cycles and lower abdominal thresholds than Dys, thresholds of both groups being significantly lower than normal (p < .001). Anaesthetic treatment versus no treatment of the lumbar TrP significantly reduced the number of painful cycles during year2 and significantly increased the abdominal thresholds (p < .0001).

CONCLUSION

Viscero-visceral hyperalgesia between uterus and urinary tract may persist after stone elimination due to nociceptive inputs from TrPs in the referred urinary area, since TrPs treatment effectively reverses the enhanced menstrual symptoms. The procedure could represent an integral part of the management protocol in these conditions.

SIGNIFICANCE

A past pain process from an internal organ can continue enhancing pain expression from a painful disease in another neuromerically connected organ (viscero-visceral hyperalgesia) if secondary myofascial trigger points (TrPs) developed in the referred area at the time of the previous visceral disease. Inactivation of these TrPs reverts the enhancement. Assessment and treatment of TrPs in referred areas from past visceral pain conditions should be systematically carried out to better control pain from current diseases in other viscera.

Visceral Origin: An Underestimated Source of Neck Pain. A Systematic Scoping Review

The diagnosis of neck pain is challenging. Many visceral disorders are known to cause it, and clinical practice guidelines recommend to rule them out during neck pain diagnosis. However, the absence of suspicion of any cause impedes one from establishing that specific aetiology as the final diagnosis. To investigate the degree of consideration given to visceral aetiology, a systematic search of trials about neck pain was carried out to evaluate their selection criteria. The search yielded 309 eligible articles, which were screened by two independent reviewers. The PEDro scale score was used to assess the methodological quality of the studies. The following information was retrieved: number of authors affiliated to a clinical or non-clinical institution, number of citations in the Web of Science, study aims, characteristics of participants, and eligibility criteria. The top 15 most cited trials, and the 15 most recent studies about treatment efficacy in neck pain, published in first quartile journals of the Journal Citation Reports, were selected. Females represented 67.5% of participants. A single study was of poor methodological quality (4/10). Based on the eligibility criteria of the articles that were systematically reviewed, it would appear that visceral aetiology was not considered in eighty percent of the trials on neck pain, showing a low level of suspicion both in research and clinical settings.

Preceding Administration of Minocycline Suppresses Plastic Changes in Cortical Excitatory Propagation in the Model Rat With Partial Infraorbital Nerve Ligation

Neuropathic pain is known to be attributable to the injured nerve, a postoperative problem induced by surgery. The infraorbital nerve (ION), a branch of the trigeminal nerve, innervates to the facial and oral regions and conveys somatosensory information to the central nervous system. The partial ligation of ION (pl-ION) is a method to mimic chronic trigeminal neuropathic pain and behavioral abnormality. To counteract induction of such abnormal pain, the effective pharmacological treatment is desired. Although recent studies have revealed the molecular mechanisms regarding chronic pain, estimation of the effectiveness of the pharmacological treatment has not been well-provided especially in the central nervous system so far. Here we examined whether pl-ION induces plastic changes in the cerebral cortex and investigated effects of minocycline on the cortical plastic changes. We performed the pl-ION to Wistar male rats (4–5 weeks old), and confirmed a mechanical nocifensive behavior in response to the mechanical stimulation with von-Frey filaments. The withdrawal threshold to mechanical stimuli of the whisker pad was decreased 1 day (1 d) after pl-ION, which continued up to 14 d after pl-ION, suggesting that pl-ION model rats presented allodynia and enhanced the response sustained at least for 14 d after pl-ION. Next, cerebrocortical activities were evaluated 3 d after pl-ION (3d-pl-ION) by the optical imaging with a voltages-sensitive dye, RH1691, to quantify the response to electrical stimulation of the whisker pad skin, mandibular molar dental pulp, and mentum skin. Electrical stimulation to the whisker pad skin induced smaller excitation in the primary sensory cortex (S1) of 3d-pl-ION in comparison to that in the sham. In contrast, cerebral cortical responses to the mandibular molar dental pulp and mentum skin stimuli increased both in S1, and the secondary somatosensory and insular oral region (S2/IOR) after pl-ION. Administration of minocycline (30 mg/kg/d) from 1 d before to 2 d after pl-ION partially recovered the pl-ION-induced changes in cortical excitation in S1 and S2/IOR in 3d-pl-ION. These results suggest that somatosensory and insular cortical excitation is changed by pl-ION, and the preceding injection of minocycline counteracts the plastic changes in the cortical activities.

Musculoskeletal Impairment: Causes of Pain with Breastfeeding Insight into 11 Cases

Objective: To determine the possible relationship between pain experienced by mothers with breastfeeding and musculoskeletal impairment commonly seen in physiotherapy practice. Evidence-based principles of the evaluation and treatment of musculoskeletal impairment used in physiotherapy practice were applied and adapted to manage pain experienced by mothers with breastfeeding. Subjects and Methods: This report describes 11 mothers referred to a breastfeeding clinic for pain with breastfeeding. Mothers were initially assessed by a physician and a nurse clinician, both International Board-Certified Lactation Consultants, to rule out causes of breast or nipple pain. When the cause remained unexplained, it was deemed musculoskeletal, and mothers were referred to a physiotherapist for assessment and treatment with manual orthopedic therapy and mobilization of the myofascial system. Results: The physiotherapist's objective musculoskeletal assessment and mothers' impression showed an improvement in the overall clinical picture after the first appointment in most mothers. Pain was resolved or alleviated by 80% in five mothers after 1-3 weekly treatments. The most useful therapeutic approach was to make afflicted mothers aware of their posture to maintain spinal alignment and avoid shear posture (lateral displacement of the trunk). Shear posture is a consequence of sitting leaning to one side. This posture is exacerbated by thoracic rotation and flexion, for example, when turning the trunk and bending over the baby while giving the breast. Conclusion: Treating musculoskeletal impairment referred pain to the breast or nipple with physiotherapy practices used in a nonbreastfeeding clientele can help alleviate or resolve pain with breastfeeding.

Recent advances in understanding and managing phantom limb pain

Post-amputation phantom limb pain (PLP) is highly prevalent and very difficult to treat. The high-prevalence, high-pain intensity levels, and decreased quality of life associated with PLP compel us to explore novel avenues to prevent, manage, and reverse this chronic pain condition. This narrative review focuses on recent advances in the treatment of PLP and reviews evidence of mechanism-based treatments from randomized controlled trials published over the past 5 years. We review recent evidence for the efficacy of targeted muscle reinnervation, repetitive transcranial magnetic stimulation, imaginal phantom limb exercises, mirror therapy, virtual and augmented reality, and eye movement desensitization and reprocessing therapy. The results indicate that not one of the above treatments is consistently better than a control condition. The challenge remains that there is little level 1 evidence of efficacy for PLP treatments and most treatment trials are underpowered (small sample sizes). The lack of efficacy likely speaks to the multiple mechanisms that contribute to PLP both between and within individuals who have sustained an amputation. Research approaches are called for to classify patients according to shared factors and evaluate treatment efficacy within classes. Subgroup analyses examining sex effects are recommended given the clear differences between males and females in pain mechanisms and outcomes. Use of novel data analytical approaches such as growth mixture modeling for multivariate latent classes may help to identify sub-clusters of patients with common outcome trajectories over time.

[Understanding of the trigger points of myalgia: acupuncture and dry needling exploration and modern acupuncture mechanism]

The similarities and differences between trigger points of myalgia and acupoints were explored. Nodules could be detected by B-ultrasound at trigger points of myalgia, but not acupoints. In clinical symptoms, the referred pain pathway of trigger points of myalgia is similar with the pathway of acupuncture meridian. Therefore, the location of trigger points of myalgia should take referred pain as pathway, which is similar with locating acupoints as meridian. Acupuncture at trigger points of myalgia takes jumping feeling as criterion, while acupuncture at acupoints are mainly based on acid swelling and numbness. From clinical observation to basic experimental research, a lot of pathophysiological evidence is provided for trigger point of myalgia. It is believed that the trigger point of myalgia might be the precise acupoint in modern scientific research, and the meridian is the synthesis of the mechanics of nerve, blood vessel and fascia. Although acupuncture and dry needling are different in theory, but the scientific foundation of TCM and western medicine is coherent.

Evaluation of Orofacial and General Pain Location in Patients With Temporomandibular Joint Disorder-Myofascial Pain With Referral

Introduction: Pain is an emotional experience. As a subjective feeling, it is associated with pathophysiological processes occurring in the central nervous system, which in turn may negatively affect the psychophysical function, cognitive abilities, level of functioning and quality of life.

The Aim: The aim of the study was to assess orofacial and general pain location in patients with temporomandibular joint disorder—myofascial pain with referral.

Materials and Methods: The study group consisted of 50 randomly selected, generally healthy people with complete natural dentition (37 women and 13 men) at the age of 23.36 ± 2.14 years, referred to the Department of Prosthodontics of the Medical University. All patients underwent clinical examination according to the Diagnostic Criteria for Temporomandibular Disorders (Axes I and II). The subjects were classified as people with myofascial pain with referral. The evaluation of severity of temporomandibular disorders was based on the Temporomandibular Disorder Pain Screener and the Graded Chronic Pain Scale. In order to assess orofacial and general pain location, a bodychart drawing of pain was used.

Results: The study group indicated 40 different areas of the body affected by pain. 2–3 isolated pain locations were declared by a total of six subjects. One person identified 17 affected areas. Forty four people reported pain in at least four regions of the body. 70% of patients suffered from pain within the right masseter muscle. Pain of the left masseter muscle was noted in 68% of cases. Cervical ailments were reported by 56% of people. Pain of the left temporomandibular joint was observed in 68% of patients, and of the right one in 54%.

Conclusion: The patients with myofascial pain with referral suffer from general ailments in different regions of the body. Only the frequency of pain in the right masseter muscle and right temporomandibular joint differed with respect to gender. The suggestion that the prevalence of pain in other areas of the body varies between men and women has not been confirmed. Due to a small sample size, such differences cannot be excluded. Further studies in this area are needed.

Jaw pain and myocardial ischemia: A review of potential neuroanatomical pathways

Cardiac pain is usually manifested as a crushing, squeezing, or sensation of pressure in the center of the chest. The pain can be referred to the left shoulder, neck, jaw, and epigastric region as well as the temporomandibular region, paranasal sinuses, and head in general. Although not well understood, during myocardial ischemia, the process of cardiac referred pain to craniofacial structures can be explained by the convergence of visceral and somatic relays at the trigeminal nucleus in the brain stem. The goal of this article is to review the possible pathways for referred jaw pain due to myocardial ischemia. Clin. Anat. 32:476-479, 2019. © 2019 Wiley Periodicals, Inc.

[The sensitization phenomenon of acupoint and biological significances]

In the pathological conditions, the human body induces somatic sensory exchanges and takes neurogenic inflammatory reactions according to referred visceral organ. Acupoint possesses both diagnosing and treating functions according to the acupuncture theory. The sensitization of acupoint refers to a pathophysiological dynamic change which is manifested predominately as a neurogenic inflammatory reaction in the specific area(s) of the body surface under pathological conditions. Furthermore, the process of acupoint from "silent" (physiological status) to "active" (pathological status) is generally represented by the dynamic changes of acupoint location, size and physicochemical environment. These responses of acupoint sensitization simultaneously activate self-healing system in the body and eventually induce the curative effects.

Calcium Pyruvate Exerts Beneficial Effects in an Experimental Model of Irritable Bowel Disease Induced by DCA in Rats

Pyruvate is a normal constituent of the body that participates in carbohydrate metabolism and functions as a scavenger of free radicals. Calcium pyruvate monohydrate (CPM) is a more stable derivative that has proved its anti-inflammatory effect in experimental colitis, among other disorders, and that could also be considered a source of calcium. Thus, it would be useful for the treatment of diseases with an inflammatory component and a high prevalence of osteoporosis like the irritable bowel syndrome (IBS). The aim of the present study is to evaluate the effects of CPM in a rat model of chronic post-inflammatory visceral pain induced by deoxycholic acid (DCA) that resembles IBS. Rats were administered DCA for three days intracolonically and then treated daily with CPM (40 and 100 mg/kg) or gabapentin (70 mg/kg) (positive control) by oral gavage for 17 days. The treatments reduced the visceral hypersensitivity measured by response to colorectal distension and referred pain. DCA induced changes in the colonic immune response characterized by increased expression of the cytokine Il-1β and the inducible enzyme Cox-2, which was reduced by the treatments. DCA also decreased the gut expression of the mucins Muc-2 and Muc-3, which was normalized by CPM, whereas gabapentin only increased significantly Muc-3. Moreover, DCA increased the expression of Tlr3, which was decreased to basal levels by all the treatments. However, the serotonin receptor Htr-4, which was also elevated, was not affected by any of the treatments, indicating no effect through this signalling pathway. In conclusion, CPM ameliorated the visceral hypersensitivity and the referred pain caused by DCA, being as effective as the control drug. Furthermore, it improved the immune status of the animals, which could contribute to the visceral analgesia and the regeneration of the intestinal epithelial barrier integrity.

Change in muscle hardness after trigger point injection and physiotherapy for myofascial pain syndrome

Assessment and treatment of masticatory myofascial pain syndrome (MPS) are not standardized and remain controversial. We examined whether muscle hardness was useful for evaluating masticatory MPS and analyzed the effectiveness of treatments such as stretching and massage (SM) and trigger point injection (TPI). Twenty healthy volunteers and 20 MPS patients were enrolled. MPS patients were divided into TPI and SM treatment groups. Hardness of masticatory muscle with a taut band (TB) and change in hardness were evaluated after SM and TPI treatments. Hardness values were significantly higher in muscle including a TB (TB point) than in the muscle of healthy controls. Visual analogue scale scores were significantly lower after SM and TPI treatments, and hardness of the TB point was significantly lower after SM but not after TPI. These results suggest that measurement of muscle hardness, including the TB, is useful for evaluating masticatory MPS. However, TPI analgesia might not be caused by change in muscle hardness. The mechanisms underlying the effects of SM and TPI on reducing pain in MPS may differ and thus warrant further research.

Percutaneous kyphoplasty for the treatment of distal lumbosacral pain caused by osteoporotic thoracolumbar vertebral fracture

Background Kyphoplasty has been demonstrated to be minimally invasive and effective in treating osteoporotic vertebral fracture patients with back pain over the level of the fractured vertebrae. Rare studies have reported on thoracolumbar vertebral fracture patients presenting with distal lumbosacral pain (DLP). Whether kyphoplasty had a favorable therapeutic benefit for these patients remains unclear. Purpose To evaluate the therapeutic efficacy of kyphoplasty in treating osteoporotic thoracolumbar vertebral fracture (OTVF) patients with DLP and assess the clinical significance of focal tenderness to palpation in these patients. Material and Methods Thirty-two OTVF patients who only complained of DLP were treated by kyphoplasty. The vertebral heights, local kyphotic angle, Visual Analogue Scale (VAS), and Oswestry Disability Index (ODI) scores were assessed preoperatively, one day after surgery, and at last follow-up. All patients were evaluated regarding their degree of satisfaction with kyphoplasty. In addition, we compared the therapeutic efficacy of kyphoplasty in patients with and without focal tenderness to palpation. Results All patients successfully underwent kyphoplasty without complications. The vertebral heights, local kyphotic angles, VAS, and ODI scores were all significantly improved after kyphoplasty and maintained at last follow-up in our patients ( P < 0.001). At last follow-up, all patients expressed satisfaction with kyphoplasty. No significant differences in these parameters were detected between patients with and without focal tenderness. Conclusion The possibility of thoracolumbar vertebral fractures in elderly patients complaining of DLP should not be neglected. Kyphoplasty presents a superior benefit in treating OTVF patients with DLP. The absence of focal tenderness does not influence the clinical efficacy in these patients.

From acute to chronic pain after thoracic surgery: the significance of different components of the acute pain response

Purpose

Acute postoperative pain is a strong predictor for postthoracotomy pain syndrome (PTPS), but the mechanism is unknown. Even though thoracic pain is usually considered the dominating acute pain after thoracic surgery, up to 45% of patients consider shoulder pain to be dominating pain and often this shoulder pain is referred visceral pain. This study aims to examine which components of the acute pain response after thoracic surgery were associated with PTPS and if any signs of a generalized central hypersensitivity could be identified in patients with PTPS.

Patients and methods

In a prospective cohort study, 60 consecutive patients for lobectomy were included and examined preoperatively and 12 months postoperatively for pain and signs of hypersensitivity using a comprehensive protocol for quantitative sensory testing. Thoracic pain, shoulder pain, referred pain, and overall pain were assessed five times daily during the first four postoperative days.

Results

Sixteen patients (31% of the 52 patients who completed the study) developed PTPS. Thoracic pain was the only pain component that was associated with PTPS and was a stronger predictor for PTPS than overall pain. There were no signs of hypersensitivity before or after the operation in patients with PTPS, but patients with PTPS more often suffered from preoperative pain.

Conclusion

Thoracic pain was the only component of the acute pain response that predicted PTPS and was a stronger predictor than overall pain.

Abdominal skeletal muscle activity precedes spontaneous menstrual cramping pain in primary dysmenorrhea

BACKGROUND

Dysmenorrhea is a pervasive pain condition that affects 20-50% of reproductive-aged women. Distension of a visceral organ, such as the uterus, could elicit a visceromotor reflex, resulting in involuntary skeletal muscle activity and referred pain. Although referred abdominal pain mechanisms can contribute to visceral pain, the role of abdominal muscle activity has not yet been investigated within the context of menstrual pain.

OBJECTIVE

The goal of this study was to determine whether involuntary abdominal muscle activity precedes spontaneous episodes of menstrual cramping pain in dysmenorrheic women and whether naproxen administration affects abdominal muscle activity.

STUDY DESIGN

Abdominal electromyography activity was recorded from women with severe dysmenorrhea (n = 38) and healthy controls (n = 10) during menses. Simultaneously, pain was measured in real time using a squeeze bulb or visual analog rheostat. Ninety minutes after naproxen administration, abdominal electromyography activity and menstrual pain were reassessed. As an additional control, women were also recorded off menses, and data were analyzed in relation to random bulb squeezes. Because it is unknown whether mechanisms of menstrual cramps are different in primary or secondary dysmenorrhea/chronic pelvic pain, the relationship between medical history and abdominal muscle activity was examined. To further examine differences in nociceptive mechanisms, pressure pain thresholds were also measured to evaluate changes in widespread pain sensitivity.

RESULTS

Abdominal muscle activity related to random-bulb squeezing was rarely observed in healthy controls on menses (0.9 ± 0.6 episodes/hour) and in dysmenorrhea participants off menses (2.3 ± 0.6 episodes/hour). In dysmenorrheic participants during menses, abdominal muscle activity frequently preceded bulb squeezing indicative of menstrual cramping pain (10.8 ± 3.0 episodes/hour; P < .004). Whereas 45% of the women with dysmenorrhea (17 of 38) had episodes of abdominal muscle activity associated pain, only 13% (5 of 38) had episodes after naproxen (P = .011). Women with the abdominal muscle activity-associated pain were less likely to have a diagnosis for secondary dysmenorrhea or chronic pelvic pain (2 of 17) than women without this pain phenotype (10 of 21; P = .034). Similarly, women with the abdominal muscle activity-associated pain phenotype had less nonmenstrual pain days per month (0.6 ± 0.5) than women without the phenotype (12.4 ± 0.3; P = .002). Women with abdominal muscle activity-associated pain had pressure pain thresholds (22.4 ± 3.0 N) comparable with healthy controls (22.2 ± 3.0 N; P = .967). In contrast, women without abdominal muscle activity-associated pain had lower pressure pain thresholds (16.1 ± 1.9 N; P = .039).

CONCLUSION

Abdominal muscle activity may contribute to cramping pain in primary dysmenorrhea but is resolvable with naproxen. Dysmenorrheic patients without cramp-associated abdominal muscle activity exhibit widespread pain sensitivity (lower pressure pain thresholds) and are more likely to also have a chronic pain diagnosis, suggesting their cramps are linked to changes in central pain processes. This preliminary study suggests new tools to phenotype menstrual pain and supports the hypothesis that multiple distinct mechanisms may contribute to dysmenorrhea.

Role of medullary astroglial glutamine synthesis in tooth pulp hypersensitivity associated with frequent masseter muscle contraction

Background

The mechanisms underlying tooth pulp hypersensitivity associated with masseter muscle hyperalgesia remain largely underinvestigated. In the present study, we aimed to determine whether masseter muscle contraction induced by daily electrical stimulation influences the mechanical head-withdrawal threshold and genioglossus electromyography activity caused by the application of capsaicin to the upper first molar tooth pulp. We further investigated whether astroglial glutamine synthesis is involved in first molar tooth pulp hypersensitivity associated with masseter muscle contraction.

Methods

The first molar tooth pulp was treated with capsaicin or vehicle in masseter muscle contraction or sham rats, following which the astroglial glutamine synthetase inhibitor methionine sulfoximine or Phosphate buffered saline (PBS) was applied. Astroglial activation was assessed via immunohistochemistry.

Results

The mechanical head-withdrawal threshold of the ipsilateral masseter muscle was significantly decreased in masseter muscle contraction rats than in sham rats. Genioglossus electromyography activity was significantly higher in masseter muscle contraction rats than sham rats. Glial fibrillary acidic protein-immunoreactive cell density was significantly higher in masseter muscle contraction rats than in sham rats. Administration of methionine sulfoximine induced no significant changes in the density of glial fibrillary acidic protein-immunoreactive cells relative to PBS treatment. However, mechanical head-withdrawal threshold was significantly higher in masseter muscle contraction rats than PBS-treated rats after methionine sulfoximine administration. Genioglossus electromyography activity following first molar tooth pulp capsaicin treatment was significantly lower in methionine sulfoximine-treated rats than in PBS-treated rats. In the ipsilateral region, the total number of phosphorylated extracellular signal-regulated protein kinase immunoreactive cells in the medullary dorsal horn was significantly smaller upon first molar tooth pulp capsaicin application in methionine sulfoximine-treated rats than in PBS-treated rats.

Conclusions

Our results suggest that masseter muscle contraction induces astroglial activation, and that this activation spreads from caudal to the obex in the medullary dorsal horn, resulting in enhanced neuronal excitability associated with astroglial glutamine synthesis in medullary dorsal horn neurons receiving inputs from the tooth pulp. These findings provide significant insight into the mechanisms underlying tooth pulp hypersensitivity associated with masseter muscle contraction.

A randomized controlled trial to study the effect of gross myofascial release on mechanical neck pain referred to upper limb

OBJECTIVE

Mechanical neck pain (NP) with referred pain to upper limb is a common problem and often leads to functional impairment of common activities of daily living. The present study is undertaken to study and compare the effect of gross myofascial release (MFR) of upper limb and neck alone with conventional physiotherapy against only conventional treatment in subjects with mechanical NP referred to upper limb in terms of cervical endurance, pain, range of motion, and function.

METHODS

Design: This was a experimental study; a total of 40 subjects clinically diagnosed with mechanical NP along with referred pain between the age group of 20 and 50 years. Intervention: Control group was given conventional treatment of hot moist pack, TENS, and stretching and strengthening exercise, and experimental group was given gross MFR of the neck and upper limb in addition to conventional therapy. Treatment was given for 6 consecutive days. Outcome measures used were pressure biofeedback to measure cervical endurance, goniometer for cervical ROM, Northwick Park NP questionnaire, and disabilities of arm, shoulder, and hand questionnaire.

RESULTS

Statistically significant change was present for pain, cervical flexure endurance, ROM, and functional abilities with P < 0.05 for both the groups except for neck flexor endurance in control group.

CONCLUSION

Gross MFR of upper limb and neck is an effective technique for subjects with mechanical NP and has a faster rate of improvement.

Role of Neuron-Glial Interaction Mediated by IL-1β in Ectopic Tooth Pain

Although many reports have demonstrated that ectopic pain develops in the orofacial region following tooth pulp inflammation, which often causes misdiagnosis and inappropriate treatment for patients with pulpitis, the precise mechanism remains unknown. In the present study, we hypothesized that the functional interaction between satellite glial cells and neurons mediated by interleukin 1β (IL-1β) in the trigeminal ganglion (TG) is involved in ectopic orofacial pain associated with tooth pulp inflammation. The digastric muscle electromyogram (D-EMG) activity elicited by capsaicin administration into the maxillary second molar tooth pulp was analyzed to evaluate the noxious reflex and was significantly increased in rats with inflammation of the maxillary first molar (M1) versus rats injected with saline. A significant increase in the expression of connexin43 (Cx43), a gap junction containing protein, was observed in activated satellite glial cells surrounding second molar-innervating neurons in the TG after M1 pulpitis. Daily administration of Gap26, a Cx43 mimetic peptide and inhibitor, in the TG significantly suppressed the enhancement of capsaicin-induced D-EMG activity and the percentage of Fluoro-Gold (FG)-labeled cells encircled by glial fibrillary acid protein-immunoreactive (IR) + Cx43-IR cells after M1 pulp inflammation ( P < 0.01). The percentage of FG-labeled cells encircled by glial fibrillary acid protein-IR + IL-1β-IR cells, IL-1 type I receptor-IR cells labeled with FG, and TRPV1-IR cells labeled with FG significantly increased after M1 pulp inflammation ( P < 0.01). Daily administration of IL-1ra, an IL-1 receptor antagonist, into the TG significantly reduced the enhancement of capsaicin-induced D-EMG activity and the percentage of TRPV1-IR neurons labeled with FG after M1 pulp inflammation ( P < 0.01). The present findings suggest that satellite glial cell is activated in the TG via activated gap junctions composed of Cx43 following tooth pulp inflammation, which leads to the hyperactivation of remote neurons via IL-1β mechanisms and results in ectopic tooth pulp pain in the adjacent tooth.

Neck-to-shoulder pain as an unusual presentation of pulmonary embolism in a patient with cervical spinal cord injury: A case report

RATIONALE

Information on referred pain can be helpful for diagnosing diseases of the visceral organs. Here, the authors report a patient with cervical spinal cord injury (SCI) who had referred pain at the right side from the neck to shoulder, as a presentation of pulmonary embolism (PE).

PATIENT CONCERNS

A 55-year-old man with complete tetraplegia, due to cervical SCI after C5 and C6 vertebral body fracture, complained of right neck-to-shoulder pain (numerical scale rating: 6). Despite pain medication (meloxicam 15 mg, gabapentin 400 mg, and propacetamol HCl 1 g), the pain was not reduced. Along with right neck-to-shoulder pain, he presented mild fever (37.8°C) and mildly elevated respiratory rate (20 breaths/min). D-dimer level was also mildly elevated to 6.09 mg/mL (normal value: < 0.5 mg/mL).

DIAGNOSES

Computed tomography pulmonary angiography revealed PE in the right lower lobe pulmonary artery.

INTERVENTIONS

For managing PE, rivaroxaban was administered for three days.

OUTCOMES

After the administration of rivaroxaban, the patient's pain completely disappeared.

LESSONS

This study shows that pain at the neck-to-shoulder area can occur following unexpected causes such as PE. Not limited to PE, the evaluation of diseases in the thoracic or abdominal organs is recommended if patients with cervical SCI present refractory pain in the dermatomes innervated by high cervical nerve roots.

A Case of Acoustic Shock with Post-trauma Trigeminal-Autonomic Activation

This study reports the case of an acoustic shock injury (ASI), which did not result in a significant hearing loss, but was followed by manifold chronic symptoms both within (tinnitus, otalgia, tingling in the ear, tension in the ear, and red tympanum) and outside the ears (blocked nose, pain in the neck/temporal region). We suggest that these symptoms may result from a loop involving injury to middle ear muscles, peripheral inflammatory processes, activation and sensitization of the trigeminal nerve, the autonomic nervous system, and central feedbacks. The pathophysiology of this ASI is reminiscent of that observed in post-traumatic trigeminal-autonomic cephalalgia. This framework opens new and promising perspectives on the understanding and medical management of ASI.

Retrospective study to identify trigeminal-cervical ocular referred pain as a new causative entity of ocular pain

Purpose

To determine the prevalence and clinical characteristics of trigeminal–cervical (TC) ocular referred pain.

Methods

A retrospective study of 1,680 patients seen during 2002–2010 was performed in an ocular surface specialty center to identify patients with or without TC pain defined as ocular pain with ipsilateral trigger points located at the occipital region. Patients with refractory TC pain despite topical anesthetics and conventional treatments received interventional injection to each trigger point.

Results

A total of 81 (4.8%) patients (study group) with TC pain and 241 patients (control group) without TC pain were identified out of the 1,680 patients over an 8 year period. There was no difference in age, gender, prior surgeries, medications, non-pain symptoms, pain laterality, and concomitant ocular diseases between the 2 groups. Multivariate regression analysis showed that patients with TC pain had a significant correlation with persistent deep ocular pain, ipsilateral trigger points (f²=99, p<0.001) but not headaches (f²=0.09, p=0.5). Injection at the trigger points achieved complete or partial pain resolution with a low recurrence rate in 43 of 45 (96%) patients with TC pain.

Conclusion

TC pain defined herein may be a different entity of ocular pain and can indeed be differentiated from other ocular pain by the referral character so that one may avoid mislabeling it as undetermined or as a reason to unnecessarily overtreat concomitant ocular diseases.

Pathophysiology of Trigger Points in Myofascial Pain Syndrome

Questions from patients about pain conditions and analgesic pharmacotherapy and responses from authors are presented to help educate patients and make them more effective self-advocates. Trigger point pathophysiology in myofascial pain syndrome, which involves muscle stiffness, tenderness, and pain that radiates to other areas of the body, is considered. The causes of trigger points and several theories about how they develop are reviewed, and treatment approaches, including stretching, physical therapy, dry needling, and injections, are offered.

Referred Pain Patterns of the Infraspinatus Muscle Elicited by Deep Dry Needling and Manual Palpation

OBJECTIVES

To identify the most common referred pain (ReP) pattern of the infraspinatus myofascial trigger point (MTrP) and compare its coincidence with the original ReP pattern, to verify whether there are any significant differences by sex and types of technique and to determine the observed signs and symptoms evoked by deep dry needling (DDN) and manual palpation (MPal).

DESIGN

A cohort study of patients randomized to two different examination methods (July and August 2016).

SETTINGS

Students and staff recruited from Miguel Hernandez University (Southeast Spain).

PATIENTS

One hundred thirty-three participants (70.7% women) with shoulder complaints were randomly assigned to either an MPal (n = 67) or DDN group (n = 66).

INTERVENTIONS

The same physiotherapist carried out the techniques on all participants, and the same protocol was followed for both the DDN and MPal groups. The physiotherapist did not ask participants about their pain features or other relevant issues.

OUTCOME MEASURES

Local twitch response (LTR) and ReP assessed through a visual analogue scale and features of ReP of the infraspinatus muscle.

RESULTS

The areas with the highest percentage of ReP were the front (area 3; 27.1%) and back (area 11; 21.1%) of the arm, anterior (area 4; 36.1%) and posterior (area 12; 42.1%) shoulder, and infraspinatus muscle area. DDN proved to be significantly easier than MPal in evoking an LTR (p ≤ 0.001). There were significant differences between sexes in zone 2 (p = 0.041) and no statistically significant differences were found by technique.

CONCLUSIONS

The ReP pattern of the infraspinatus muscle coincides with the original pattern described by Travell and Simons, although the neck area should be questioned. The study found no significant differences in the ReP pattern by sex and when comparing MPal with DDN of MTrP of the infraspinatus muscle. DDN proved to be significantly easier than MPal in evoking an LTR.

Tensiomyography, sonoelastography, and mechanosensitivity differences between active, latent, and control low back myofascial trigger points: A cross-sectional study

The myofascial pain syndrome (MPS) is considered the most common musculoskeletal condition. The lumbopelvic pain (LPP) is established as one of the most prevalent musculoskeletal disorders. Nevertheless, previous research has not yet studied the contractibility changes by tensiomyography between myofascial trigger point (MTrP) types and normal tissue. Therefore, the aim of this study was to determine the tensiomyography, sonoelastography, and pressure pain threshold (PPT) differences between the palpation area of active and latent MTrPs with regards to control points in the lumbar erector spinae muscles of subjects with LPP. A cross-sectional descriptive study was performed. A convenience sample of 60 points (20 active MTrPs, 20 latent MTrPs, and 20 control points) was registered bilaterally in the lumbar erector spinae muscles from subjects with nonspecific LPP. The palpation order of active MTrPs, latent MTrPs, or control points was randomized for each side. The outcome assessors were blinded to the order or point type. The outcome measurements order for each point was sonoelastography manual strain index, tensiomyography, and PPT, separated by 15 minutes. Five contractile objective parameters were: maximal radial displacement (Dm), contraction time (Tc), sustain time (Ts), delay time (Td), and half-relaxation time (Tr). Tensiomyography parameters did not show any statistically significant difference (P > 0.05) between active MTrPs, latent MTrPs, and control points. Nevertheless, PPT and sonoelastography showed statistically significant differences (P < 0.05) between all point types, except for active and latent MTrPs PPT comparison (P = 0.091). Regarding the active MTrPs, a moderate positive correlation was observed between PPT and Dm (P = 0.047; τB = 0.450). Considering the control points, a moderate positive correlation was shown between sonoelastography and Td (P = 0.044; τB = 0.328). The tensiomyography contractile properties did not seem to show differences, while the sonoelastography and mechanosensitivity presented a higher stiffness and a lower PPT, respectively, between the palpation area of active and latent MTrPs with regards to control points in the lumbar erector spinae muscles of subjects with LPP. Considering the correlations, further research is needed regarding the muscle contractile properties modifications under MPS treatments, especially Dm in active MTrPs and Td in normal sites.

Spatiotemporal Profiles of Proprioception Processed by the Masseter Muscle Spindles in Rat Cerebral Cortex: An Optical Imaging Study

Muscle spindles in the jaw-closing muscles, which are innervated by trigeminal mesencephalic neurons (MesV neurons), control the strength of occlusion and the position of the mandible. The mechanisms underlying cortical processing of proprioceptive information are critical to understanding how sensory information from the masticatory muscles regulates orofacial motor function. However, these mechanisms are mostly unknown. The present study aimed to identify the regions that process proprioception of the jaw-closing muscles using in vivo optical imaging with a voltage-sensitive dye in rats under urethane anesthesia. First, jaw opening that was produced by mechanically pulling down the mandible evoked an optical response, which reflects neural excitation, in two cortical regions: the most rostroventral part of the primary somatosensory cortex (S1) and the border between the ventral part of the secondary somatosensory cortex (S2) and the insular oral region (IOR). The kinetics of the optical signal, including the latency, amplitude, rise time, decay time and half duration, in the S1 region for the response with the largest amplitude were comparable to those in the region with the largest response in S2/IOR. Second, we visualized the regions responding to electrical stimulation of the masseter nerve, which activates both motor efferent fibers and somatosensory afferent fibers, including those that transmit nociceptive and proprioceptive information. Masseter nerve stimulation initially excited the rostral part of the S2/IOR region, and an adjacent region responded to jaw opening. The caudal part of the region showing the maximum response overlapped with the region responding to jaw opening, whereas the rostral part overlapped with the region responding to electrical stimulation of the maxillary and mandibular molar pulps. These findings suggest that proprioception of the masseter is processed in S1 and S2/IOR. Other sensory information, such as nociception, is processed in a region that is adjacent to these pulpal regions and is located in the rostral part of S2/IOR, which receives nociceptive inputs from the molar pulps. The spatial proximity of these regions may be associated with the mechanisms by which masseter muscle pain is incorrectly perceived as dental pain.

Spinal nociceptive transmission by mechanical stimulation of bone marrow

Background

Since bone marrow receives innervation from A-delta and C-fibers and since an increase in intramedullary pressure in bone marrow may induce acute pain in orthopedic patients during surgery and chronic pain in patients with bone marrow edema, skeletal pain may partly originate from bone marrow. Intraosseous lesions, such as osteomyelitis and bone cancer, are also known to produce cutaneous hypersensitivity, which might be referred pain from bone. However, little is known about pain perception in bone marrow and referred pain induced by bone disease. Thus, we carried out an in vivo electrophysiological study and behavioral study to determine whether increased intraosseous pressure of the femur induces acute pain and whether increased intraosseous pressure induces referred pain in the corresponding receptive fields of the skin.

Results

Intraosseous balloon inflation caused spontaneous pain-related behavior and mechanical hyperalgesia and allodynia in the lumbosacral region. Single neuronal activities of spinal dorsal horn neurons were extracellularly isolated, and then evoked responses to non-noxious and noxious cutaneous stimuli and intraosseous balloon inflation were recorded. Ninety-four spinal dorsal horn neurons, which had somatic receptive fields at the lower back and thigh, were obtained. Sixty-two percent of the wide-dynamic-range neurons (24/39) and 86% of the high-threshold neurons (12/14) responded to intraosseous balloon inflation, while none of the low-threshold neurons (0/41) responded to intraosseous balloon inflation. Spinally administered morphine (1 µg) abolished balloon inflation-induced spontaneous pain-related behavior and mechanical hyperalgesia in awake rats and also suppressed evoked activities of wide-dynamic-range neurons to noxious cutaneous stimulation and intraosseous balloon inflation.

Conclusions

The results suggest that mechanical stimulation to bone marrow produces nociception, concomitantly producing its referred pain in the corresponding skin fields. These mechanisms might contribute to pain caused by skeletal diseases.

Sacroiliac Coalition: First Description and Report of a Successful Resection

Study Design Case report. Objective This report describes the first case of a sacroiliac coalition, its clinical features, the diagnostic difficulties, and the surgical treatment chosen in this case. Methods A 33-year-old man presented to our outpatient clinics complaining of severe left-sided low back pain with an intermitted nondermatomal radiation into the left thigh. The only abnormality on a pelvic radiograph was a coin-size, faint hyperdensity, which was almost overlooked. Subsequent computed tomography (CT) and magnetic resonance imaging (MRI) confirmed two bridging bone spurs on the anterior surface of the left joint with a fibrous interruption at the apex. After the conservative treatment failed, a surgical treatment was offered to the patient. The coalition was resected via an anterior retroperitoneal approach and through the tissue plane between the psoas and the iliacus muscles. A histopathologic examination was performed and confirmed the diagnosis of a coalition. Results The patient's pain resolved immediately after surgery. After 8 months, a follow-up CT scan showed complete removal of the coalition without any signs of recurrence, and at 12 months' follow-up, the patient remained pain-free. Conclusions This is the first published case of a sacroiliac coalition. The only sign of this rare condition on the plain radiographs was very easy to miss. As has been discussed in the literature, CT and MRI are important in the differential diagnostics of such lesions. The histopathologic findings included that of a fibrous bar, confirming the diagnosis, which is further corroborated by the complete resolution of the symptoms.