Effects of pain on cortical homeostatic plasticity in humans: a systematic review

Homeostatic plasticity (HP) is a negative feedback mechanism that prevents excessive facilitation or depression of cortical excitability (CE). Cortical HP responses in humans have been investigated by using 2 blocks of noninvasive brain stimulation with a no-stimulation block in between. A healthy HP response is characterized by reduced CE after 2 excitatory stimulation blocks and increased CE when using inhibitory stimulation. Conversely, impaired HP responses have been demonstrated in experimental and chronic pain conditions. Therefore, this systematic review aimed to provide an overview of the effect of pain on cortical HP in humans. Scopus, Embase, and PubMed were searched from inception until November 20, 2023. The included studies (1) compared experimental or clinical pain conditions with healthy controls, (2) induced HP using 2 blocks of stimulation with a no-stimulation interval, and (3) evaluated CE measures such as motor-evoked potentials. Four studies were included, consisting of 5 experiments and 146 participants, of whom 63 were patients with chronic pain and 48 were subjected to an experimental pain model. This systematic review found support for an HP impairment in pain compared with that in pain-free states, reflected by a lack of CE reduction after excitatory-excitatory HP induction over the primary motor cortex. Inhibitory-inhibitory HP induction did not produce a consistent HP response across studies, independent of pain or pain-free states. Standardization of HP induction protocols and outcome calculations is needed to ensure reproducibility and study comparison. Future HP studies may consider investigating sensory domains including nociception, which would further our understanding of abnormal HP regulation in pain conditions.

Thematic synthesis of the experiences of people with hidradenitis suppurativa: a systematic review

BACKGROUND

Although hidradenitis suppurativa (HS) is known to affect quality of life, little summative knowledge exists on how HS impacts people living with the condition.

OBJECTIVES

To synthesize experiences of people with HS within published qualitative research.

METHODS

Searches on databases MEDLINE, PsycINFO, Embase and CINAHL were conducted on 17 April 2020. Two independent reviewers screened 5512 publications. Study quality was assessed using the National Institute for Health and Care Excellence quality appraisal checklist for qualitative studies. Thematic synthesis generated descriptive and analytic themes.

RESULTS

Fourteen studies were included: four studies fulfilled most quality criteria, eight fulfilled some quality criteria, and two fulfilled few quality criteria. There were three final themes. (i) Putting the brakes on life. The physical, psychological and social consequences of HS resulted in people missing out on multiple life events. This could have a cumulative effect that influences the trajectory of someone's life. (ii) A stigmatized identity: concealed and revealed. People try to conceal their HS, visually and verbally, but this results in anticipation and fear of exposure. Social support and psychological acceptance helped people cope. Connecting to others with HS may have a specific role in preserving a positive self-identity. (iii) Falling through the cracks. Delayed diagnosis, misdiagnosis and lack of access to care were reported. People felt unheard and misunderstood by healthcare professionals, and healthcare interactions could enhance feelings of shame.

CONCLUSIONS

There need to be improvements to clinical care to allow people with HS to live their life more fully.

Research priorities and identification of a health-service delivery model for psoriasis from the UK Psoriasis Priority Setting Partnership

BACKGROUND

Psoriasis impacts the health and psychosocial functioning of patients, conferring a significant economic burden on healthcare systems. There remain unmet needs in psoriasis care, which if addressed by research, could improve clinical outcomes.

AIM

To research priorities and identify a health service delivery model from the UK Psoriasis Priority Setting Partnership (PsPSP).

METHODS

Between July 2017 and November 2018, we invited people with lived experience of psoriasis and healthcare professionals to (i) identify unmet needs, and (ii) prioritize the order in which these should be addressed by research. We collaborated with the Psoriasis Association and used methodology established by the James Lind Alliance, which pioneers the joint setting of research priorities by patients and clinicians worldwide.

RESULTS

In our initial harvesting survey (Survey 1), 2133 questions were submitted by 805 individuals. Submissions that had not been answered by research (true uncertainties) were supplemented with evidence gaps from systematic reviews/guidelines published in the previous 5 years and refined to produce 55 indicative questions. Voting in Survey 2, by 1154 individuals, enabled a shortlist of questions, which were prioritized during the final workshop to produce a top 20 list of research questions. Submissions on health service delivery (5.8% of the total submissions), which were analysed separately, described a blueprint for psoriasis care.

CONCLUSIONS

The PsPSP will inform the translational research agenda, ensuring that future research is relevant for the needs of people with psoriasis and those who manage the disease. Submissions on health service delivery describe a model of holistic, patient-focused care providing high-quality, effective management for patients with psoriasis.

Alterations in Temporal Summation of Pain and Conditioned Pain Modulation Across an Episode of Experimental Exercise-Induced Low Back Pain

Persistent pain conditions, including low back pain (LBP), are often accompanied by alterations in pronociceptive and antinociceptive mechanisms, as quantified by temporal summation of pain (TSP) and conditioned pain modulation (CPM). It remains unclear whether altered pain sensitivity, CPM, and/or TSP are a consequence of pain presence or determine the degree of pain development. Pressure pain sensitivity, TSP, and CPM were assessed across an episode of exercise-induced LBP maintained for several days. Thirty healthy individuals participated in 3 experimental sessions: before (day 0), 2 days after fatiguing back muscle exercise with exercise-induced LBP present (day 2), and after pain resolution (day 7). Both handheld and cuff pressure-pain thresholds, along with TSP (10-cuff pain stimuli at .5 Hz) and CPM (cuff pain detection threshold prior versus during painful pressure conditioning) were assessed, alongside questionnaires pertaining to pain, disability, mood, sleep, menstruation, physical activity, and catastrophizing. The exercise-induced LBP model produced mild pain and disability, and reductions in pressure pain thresholds over both the lumbar and distant testing sites (p < .007). No pain-related changes were observed for TSP (p > .44) or CPM (p > .17). The baseline TSP was associated with the peak pain intensity of the exercise-induced LBP (p < .003). Perspective: Pressure-pain sensitivity was impacted by the presence of exercise-induced LBP, whereas TSP seemed to be more stable and was instead associated with the intensity of pain developed. No significant pain-related changes or associations were observed for CPM, suggesting this measure may have less usefulness in mild musculoskeletal pain conditions.

Review article: Best practice management of neck pain in the emergency department (part 6 of the musculoskeletal injuries rapid review series)

Neck pain and whiplash injuries are a common presentation to the ED, and a frequent cause of disability globally. This rapid review investigated best practice for the assessment and management of musculoskeletal neck pain in the ED. PubMed, CINAHL, EMBASE, TRIP and the grey literature, including relevant organisational websites, were searched in 2017. Primary studies, systematic reviews and guidelines were considered for inclusion. English-language articles published in the past 12 years addressing acute neck pain assessment, management or prognosis in the ED were included. Data extraction was conducted, followed by quality appraisal to rate levels of evidence where possible. The search revealed 2080 articles, of which 51 were included (n = 22 primary articles, n = 13 systematic reviews and n = 16 guidelines). Consistent evidence was found to support the use of 'red flags' to screen for serious pathologies, judicious use of imaging through clinical decision rule application and promotion of functional exercise coupled with advice and reassurance. Clinicians may also consider applying risk-stratification methods, such as using a clinical prediction rule, to guide patient discharge and referral plans; however, the evidence is still emerging in this population. This rapid review provides clinicians managing neck pain in the ED a summary of the best available evidence to enhance quality of care and optimise patient outcomes.

Review article: Best practice management of common shoulder injuries and conditions in the emergency department (part 4 of the musculoskeletal injuries rapid review series)

Shoulder injuries are a commonly presenting complaint to the ED. In the absence of an obvious deformity, they can be difficult to assess and definitively diagnose because of the multiple structures that cause shoulder pain, the acuity and severity of pain and the lack of range of motion in the ED setting. The quality of ED care provided to patients with musculoskeletal shoulder pain is crucial to ensure the best possible outcomes for the patient. This rapid review investigated best practice for the assessment and management of common shoulder injuries and conditions in the ED. Databases were searched in 2017, including PubMed, CINAHL, EMBASE, TRIP and the grey literature, including relevant organisational websites. Primary studies, systematic reviews and guidelines published in English-language in the past 12 years that addressed the acute assessment, management, follow-up plan or prognosis were considered for inclusion. Data extraction of included articles was conducted, followed by quality appraisal to rate the level of evidence. The search revealed 1902 articles, of which 73 were included in the review (n = 12 primary articles, n = 49 systematic reviews and n = 12 guidelines). This rapid review provides clinicians who manage shoulder dislocations, fractures and soft tissue injuries in the ED a summary of the best available evidence to enhance the quality of care for optimal patient outcomes. There is strong evidence to support taking a thorough history and physical examination, with cautious use of special tests because of their poor diagnostic accuracy. Key points regarding the diagnosis and management of these injuries are provided.

Review article: Best practice management of common knee injuries in the emergency department (part 3 of the musculoskeletal injuries rapid review series)

Knee injuries are a common presentation to the ED and are often difficult to assess and definitively diagnose due to the patient's acute pain, effusion and guarding. The quality of ED care provided to patients with fractures or soft tissue injuries of the knee is critical to ensure the best possible outcomes for the patient. This rapid review investigated best practice for the assessment and management of common knee injuries in the ED. Databases were searched in 2017, including PubMed, CINAHL, EMBASE, TRIP and the grey literature, including relevant organisational websites. Primary studies, systematic reviews and guidelines were considered for inclusion. English-language articles published in the past 12 years that addressed the acute assessment, management, follow-up plan or prognosis were included. Data extraction of included articles was conducted, followed by quality appraisal to rate the level of evidence where possible. The search revealed 2250 articles, of which 54 were included in the review (n = 8 primary articles, n = 28 systematic reviews, n = 18 guidelines). This rapid review provides clinicians managing fractures and soft tissue injuries of the knee in the ED, a summary of the best available evidence to enhance the quality of care for optimal patient outcomes. There is consistent evidence to support undertaking a thorough history and physical examination, including the application of special tests and clinical decision rules for imaging. In the undifferentiated knee injury, expedited follow up and further imaging is recommended to improve patient outcomes and cost-effectiveness.

Review article: Best practice management of common ankle and foot injuries in the emergency department (part 2 of the musculoskeletal injuries rapid review series)

Ankle and foot injuries are the most common musculoskeletal injuries presenting to Australian EDs and are associated with a large societal and economic impact. The quality of ED care provided to patients with ankle and foot fractures or soft tissue injuries is critical to ensure the best possible outcomes for the patient. This rapid review investigated best practice for the assessment and management of common ankle and foot injuries in the ED. Databases including PubMed, CINAHL, EMBASE, TRIP and the grey literature, including relevant organisational websites, were searched in 2017. Primary studies, systematic reviews and guidelines were considered for inclusion. English language articles published in the last 12 years that addressed the acute assessment, management or prognosis in the ED were included. Data extraction of included articles was conducted, followed by quality appraisal to rate the level of evidence where possible. The search revealed 1242 articles, of which 71 were included in the review (n = 22 primary articles, n = 35 systematic reviews and n = 14 guidelines). This rapid review provides clinicians managing fractures and soft tissue injuries of the ankle and foot in the ED a summary of the best available evidence to enhance the quality of care for optimal patient outcomes. Following a thorough history and physical examination, including the application of the Ottawa ankle rules, ED clinicians should not only provide a diagnosis, but rate the severity of soft tissue injuries, or stability of fractures and dislocations, which are the pivotal decision points in guiding ED treatment, specialist referral and the follow-up plan.

Investigating the effect of forestry on leaf-litter arthropods (Algonquin Park, Ontario, Canada)

Arthropods are the most diverse taxonomic group of terrestrial eukaryotes and are sensitive to physical alterations in their environment such as those caused by forestry. With their enormous diversity and physical omnipresence, arthropods could be powerful indicators of the effects of disturbance following forestry. When arthropods have been used to measure the effects of disturbance, the total diversity of some groups is often found to increase following forestry. However, these findings are frequently derived using a coarse taxonomic grain (family or order) to accommodate for various taxonomic impediments (including cryptic diversity and poorly resourced taxonomists). Our intent with this work was to determine the diversity of arthropods in and around Algonquin Park, and how this diversity was influenced by disturbance (in this case, forestry within the past 25 years). We used DNA barcode-derived diversity estimates (Barcode Index Number (BIN) richness) to avoid taxonomic impediments and as a source of genetic information with which we could conduct phylogenetic estimates of diversity (PD). Diversity patterns elucidated with PD are often, but not always congruent with taxonomic estimates-and departures from these expectations can help clarify disturbance effects that are hidden from richness studies alone. We found that BIN richness and PD were greater in disturbed (forested) areas, however when we controlled for the expected relationship between PD and BIN richness, we found that cut sites contained less PD than expected and that this diversity was more phylogenetically clustered than would be predicted by taxonomic richness. While disturbance may cause an evident increase in diversity, this diversity may not reflect the full evolutionary history of the assemblage within that area and thus a subtle effect of disturbance can be found decades following forestry.

Reduced Maximal Force during Acute Anterior Knee Pain Is Associated with Deficits in Voluntary Muscle Activation

Although maximal voluntary contraction (MVC) force is reduced during pain, studies using interpolated twitch show no consistent reduction of voluntary muscle drive. The present study aimed to test if the reduction in MVC force during acute experimental pain could be explained by increased activation of antagonist muscles, weak voluntary activation at baseline, or changes in force direction. Twenty-two healthy volunteers performed maximal voluntary isometric knee extensions before, during, and after the effects of hypertonic (pain) and isotonic (control) saline injections into the infrapatellar fat pad. The MVC force, voluntary activation, electromyographic (EMG) activity of agonist, antagonist, and auxiliary (hip) muscles, and pain cognition and anxiety scores were recorded. MVC force was 9.3% lower during pain than baseline (p < 0.001), but there was no systematic change in voluntary activation. Reduced MVC force during pain was variable between participants (SD: 14%), and was correlated with reduced voluntary activation (r = 0.90), baseline voluntary activation (r = − 0.62), and reduced EMG amplitude of agonist and antagonist muscles (all r > 0.52), but not with changes in force direction, pain or anxiety scores. Hence, reduced MVC force during acute pain was mainly explained by deficits in maximal voluntary drive.

Reliability of Abdominal Muscle Stiffness Measured Using Elastography during Trunk Rehabilitation Exercises

The aim of this study was to assess the intra-session and inter-rater reliability of shear modulus measured in abdominal muscles during two commonly used trunk stability exercises. Thirty healthy volunteers performed a series of abdominal hollow and abdominal brace tasks. Supersonic shear imaging was used to measure the shear modulus (considered an index of muscle tension) of the four anterior trunk muscles: obliquus externus abdominis, obliquus internus abdominis, transversus abdominis and rectus abdominis. Because of measurement artifacts, internus abdominis and transversus abdominis data were not analyzed for 36.7% and 26.7% of the participants, respectively. These participants exhibited thicker superficial fat layers than the others. For the remaining participants, fair to excellent intra-session and inter-rater reliability was observed with moderate to high intra-class coefficients (0.45-0.97) and low to moderate standard error of measurement values (0.38-3.53 kPa). Reliability values were consistently greater for superficial than for deeper muscles.

Renal injury management in an urban trauma centre and implications for urological training

INTRODUCTION

The aim of this study was to analyse the treatment and management of renal injury patients presenting to our major trauma unit to determine the likelihood of patients needing immediate nephrectomy.

METHODS

The Trauma Audit and Research Network (TARN) database was used to review trauma cases presenting to our department between February 2009 and September 2013. Demographic data, mechanism and severity of injury, grade of renal trauma, management and 30-day outcome were determined from TARN data, electronic patient records and imaging.

RESULTS

There were a total of 1,856 trauma cases, of which 36 patients (1.9%) had a renal injury. In this group, the median age was 28 years (range: 16-92 years), with 28 patients (78%) having blunt renal trauma and 8 (22%) penetrating renal trauma. The most common cause for blunt renal trauma was road traffic accidents. Renal trauma cases were stratified into American Association for the Surgery of Trauma (AAST) grades (grade I: 19%, grade II: 22%, grade III: 28%, grade IV: 28%, grade V: 0%). All patients with grade I and II injuries were treated conservatively. There were three patients (1 with grade III and 2 with grade IV renal injuries) who underwent radiological embolisation. One of these patients went on to have a delayed nephrectomy owing to unsuccessful embolisation.

CONCLUSIONS

Trauma patients rarely require emergency nephrectomy. Radiological selective embolisation provides a good interventional option in cases of active bleeding from renal injury in haemodynamically stable patients. This has implications for trauma care and how surgical cover is provided for the rare event of nephrectomy.

The Hidradenitis Suppurativa Priority Setting Partnership

BACKGROUND

Hidradenitis suppurativa (HS) has been neglected by medical researchers and society in general, despite being a relatively common, painful, chronic skin disease.

OBJECTIVES

To generate a top 10 list of HS research priorities, from the perspectives of patients with HS, carers and clinicians, to take to funding bodies.

METHODS

A priority setting partnership was established between patients with HS, carers and clinicians, following the James Lind Alliance process. Survey 1 requested submission of HS uncertainties, which were grouped into 'indicative uncertainties' for prioritization in survey 2. The 30 highest-ranked indicative uncertainties were reduced to a 'top 10' list using nominal group technique at a prioritization workshop attended by all relevant HS stakeholders.

RESULTS

In total 1495 potential uncertainties were submitted in survey 1, including 57% from patients with HS and carers, and grouped into 55 indicative uncertainties. Ranking in survey 2 was completed by 371 participants, 50% of whom were patients and carers. The final workshop was attended by 22 HS stakeholders and four facilitators and produced a top 10 list, the three highest priorities in descending order being (i) What is the most effective and safe group of oral treatments in treating HS? (ii) What is the best management of an acute flare? (iii)What is the impact of HS and its treatment on people with HS?

CONCLUSIONS

The top 10 HS research priorities have been directly disseminated to funders to raise awareness of HS. The next step is to generate research questions that will provide the evidence needed to improve care for patients with HS.

Soft tissue sarcoma of the hand

A retrospective review of our institute's tumor registry from January 1972 to January 1996 revealed 24 patients with a diagnosis of primary soft tissue sarcoma of the hand, from a total of 570 extremity soft tissue sarcomas (4%). The most frequent histologic type was malignant fibrous histiocytoma, which occurred in 9 (38%) of the 24 patients. The second most common histologic type was epithelioid sarcoma, which occurred in 6 (25%) patients. There was a statistically significant difference in the rate of local recurrence based on the type of treatment in which amputation was superior to the other forms of treatment. There was no statistically significant difference in the rate of distant failures between treatment groups. The estimated cumulative 5- and 10-year overall survival rates for all patients were 59% and 53%, respectively. Stage II patients had estimated cumulative 5- and 10-year survival rates of 68% and 59%, respectively. Stage III patients had a cumulative 5-year survival rate of 20%. Factors that were statistically significant in predicting survival were the size of the primary tumor, with tumors smaller than 5 cm having a better prognosis, and stage of the tumor at presentation, with stage I and II tumors having the highest survival rate. In selected patients with a primary hand sarcoma, aggressive limb-sparing surgery with adjuvant therapy offered equivalent survival compared with amputation.

Synthesis and evaluation of [123I]labelled analogues of the partial inverse agonist Ro 15-4513 for the study of diazepam-insensitive benzodiazepine receptors

The imidazobenzodiazepines ethyl 8-iodo-5,6 dihydro-5-methyl-6-oxo-4H-imidazo[1,5a][1,4] benzodiazepine-3-carboxylate 1 and tert-butyl 8-iodo-5,6 dihydro-5-methyl-6-oxo-4H-imidazo [1,5a][1,4] benzodiazepine-3-carboxylate 2 were prepared to study the diazepam-insensitive (DI) benzodiazepine receptor (BZR) subtype. The [123I] analogues were prepared via iododestannylation reactions in radiochemical yields of 70-80% and a specific activity >2,500 Ci/mmol. The tert-butyl analogue [123I]-2 exhibited nanomolar affinity for BZRs in homogenate membranes of rat cerebellum with Kd values for the diazepam-sensitive (DS) and DI receptors of 3.18 +/- 0.58 and 13.55 +/- 2.72 nM, respectively. The Bmax for cerebellar DS and DI receptors were 1,276 +/- 195 and 518 +/- 26 fmol/mg protein, respectively.

Sarcoma of the breast: implications of the extent of local therapy

Although the majority of breast neoplasms will be of epithelial origin, tumors of the stromal elements of the breast may occur. A retrospective review of the medical records and tumor registry data of 25 patients with breast sarcoma treated at Roswell Park Cancer Institute from 1964 to 1995 was performed. There were 24 females and 1 male, with a median age of 55 years. Delay in seeking medical attention was common. Angiosarcoma was the most common histologic type of breast sarcoma (n = 10). Mastectomy was the predominant form of local therapy (21 patients). Overall survival was 61 per cent at 5 years and 36 per cent at 10 years. There was no difference in survival or local control rates for those patients treated with local excision when compared with patients treated with mastectomy. Sarcoma is an unusual form of breast tumor. Survival and local control are similar when comparing local excision and mastectomy. When local excision is performed, attention must be directed to achieving clear margins of resection. The benefit of adjuvant therapy remains undefined.

Splenic venous hypertension presenting as variceal hemorrhage caused by portal hypertension

BACKGROUND

Splenic venous hypertension (SVH) may cause variceal hemorrhage that is clinically indistinguishable from similar bleeding caused by portal hypertension (PH). This may lead to erroneous treatment, including inappropriate portosystemic shunt placement.

STUDY DESIGN

A retrospective review of 58 cases of variceal hemorrhage referred for transmesenteric variceal sclerotherapy and transvenous intrahepatic portosystemic shunt (TIPS) placement revealed that seven patients had SVH as a cause of bleeding, and required treatment other than TIPS. The role of medical imaging in the diagnosis and management of SVH was analyzed.

RESULTS

Clinical data did not permit a differential diagnosis between PH and SVH as the cause of bleeding in all cases. Splenic venous hypertension was suspected and then confirmed exclusively by contrast-enhanced computed tomography (CT) and angiography, which are essential for correct patient management.

CONCLUSIONS

Computed tomography should be routinely performed to exclude SVH before TIPS placement. In instances in which CT fails to establish the diagnosis or splenic artery occlusion is considered for patient management, angiography may be used.

Cylindrical irradiator fiber tip for photodynamic therapy

In photodynamic therapy (PDT) the uniform distribution of intratumor or externally applied light is desirable but often difficult to achieve. An optical fiber tip producing cylindrical or lateral light emission can facilitate the application of laser energy by direct implantation of the tip into solid tumors or within tubular cavities of the body such as the bronchus or esophagus. A procedure is described for fabricating such a fiber tip, the main component of which is a hollow glass cylinder containing a light-scattering material. Light distributions emitted from the tip in air are documented. Useful properties of the tip include good light distribution, durability, heat resistance, and simplicity of construction.

Amniotic fluid volume and composition following experimental manipulations in sheep

Twenty to thirty percent of amniotic fluid volume was replaced by isotonic solutions of saline, mannitol, or dextrose in chronically cannulated ovine fetuses. In all cases the sodium, potassium, and chloride concentrations returned to control values in 3 to 6 hours. Urea and creatinine behaved similarly in the saline and mannitol experiments, but rose above control values within 1 hour of dextrose replacement. Amniotic fluid volume increased with return of solute. Fetal urine drainage to the exterior abolished the rapid return of urea and creatinine concentrations in the dextrose experiments, although no changes in renal function occurred in any experiments. It was concluded that dextrose inhibited the exit of urea and creatinine from the amniotic compartment.

The rationale of urinary diversion in cancer patients

A retrospective review of 218 consecutive nephrostomies done on uremic cancer patients has revealed an alarming incidence of postoperative morbidity and mortality. This review has raised legitimate questions regarding the value of palliative urinary diversion. We present a rationale to assist physicians in the management of this clinical problem.