Clinical Pain Studies Research Articles

Clinical Study of Pain in Right Iliac Fossa at Tertiary Care Hospital in Western Rajasthan

Clinical Study of Pain in Right Iliac Fossa at Tertiary Care Hospital in Western Rajasthan

The influence of cranio-cervical rehabilitation in patients with myofascial temporomandibular pain disorders.

The aim of the study was to prove the causality between the craniocervical dysfunction and myofascial pain in the head and neck and to demonstrate the clinical value and usefulness of physiotherapy as one of the therapeutic options for myofascial pain. The group of patients diagnosed with myofascial dysfunctional pain syndrome contained 98 patients out of which 79 patients (81 %) were females and 19 patients (19 %) were males. The majority of the patients were aged between 26 and 35 years; the total age range was 14-77 years with the average of 38 years. Observed patients were subdivided into three groups. Standard therapeutic methods aimed at the temporomandibular joint were provided to the patients of the first group. The second group of the patients received therapy aimed at cervical muscles only. Complex rehabilitation was applied in the third group of patients. The most frequent method used in the evaluation of chronic musculoskeletal pain in clinical studies is the visual analogue scale (VAS). According to our results, all three groups of patients saw an improvement in pain perception, but the overall subjective remission of painful sensations in the third group took place in as many as 88 % of patients. In this group, there was a significant decrease in the tenderness of trigger points in the trapezius and sternocleidomastoid muscles. It was proved that a combination of simple relaxing and stretching exercises of cervical muscles with a standard method used in the therapy of masticatory muscles is significantly more efficient (Fig. 5, Ref. 18).

Clinical Study and Management of Phantom Limb Pain

Clinical Study and Management of Phantom Limb Pain

Feasibility of Non-invasive Brain Modulation for Management of Pain Related to Chemoradiotherapy in Patients with Advanced Head and Neck Cancer.

Patients with head and neck cancer often experience a significant decrease in their quality of life during chemoradiotherapy (CRT) due to treatment-related pain, which is frequently classified as severe. Transcranial direct current stimulation (tDCS) is a method of non-invasive brain stimulation that has been frequently used in experimental and clinical pain studies. In this pilot study, we investigated the clinical impact and central mechanisms of twenty primary motor cortex (M1) stimulation sessions with tDCS during 7 weeks of CRT for head and neck cancer. From 48 patients screened, seven met the inclusion criteria and were enrolled. Electroencephalography (EEG) data were recorded before and after tDCS stimulation as well as across the trial to monitor short and long-term impact on brain function. The compliance rate during the long trial was extremely high (98.4%), and patients mostly reported mild side effects in line with the literature (e.g., tingling). Compared to a large standard of care study from our institution, our initial results indicate that M1-tDCS stimulation has a pain relief effect during the CRT that resulted in a significant attenuation of weight reduction and dysphagia normally observed in these patients. These results translated to our patient cohort not needing feeding tubes or IV fluids. Power spectra analysis of EEG data indicated significant changes in α, β, and γ bands immediately after tDCS stimulation and, in addition, α, δ, and θ bands over the long term in the seventh stimulation week (p < 0.05). The independent component EEG clustering analysis showed estimated functional brain regions including precuneus and superior frontal gyrus (SFG) in the seventh week of tDCS stimulation. These areas colocalize with our previous positron emission tomography (PET) study where there was activation in the endogenous μ-opioid system during M1-tDCS. This study provides preliminary evidence demonstrating the feasibility and safety of M1-tDCS as a potential adjuvant neuromechanism-driven analgesic therapy for head and neck cancer patients receiving CRT, inducing immediate and long-term changes in the cortical activity and clinical measures, with minimal side-effects.

Pressure and cold pain threshold reference values in a large, young adult, pain-free population

Background and aimsCurrently there is a lack of large population studies that have investigated pain sensitivity distributions in healthy pain free people. The aims of this study were: (1) to provide sex-specific reference values of pressure and cold pain thresholds in young pain-free adults; (2) to examine the association of potential correlates of pain sensitivity with pain threshold values. MethodsThis study investigated sex specific pressure and cold pain threshold estimates for young pain free adults aged 21–24 years. A cross-sectional design was utilised using participants (n=617) from the Western Australian Pregnancy Cohort (Raine) Study at the 22-year follow-up. The association of site, sex, height, weight, smoking, health related quality of life, psychological measures and activity with pain threshold values was examined. Pressure pain threshold (lumbar spine, tibialis anterior, neck and dorsal wrist) and cold pain threshold (dorsal wrist) were assessed using standardised quantitative sensory testing protocols. ResultsReference values for pressure pain threshold (four body sites) stratified by sex and site, and cold pain threshold (dorsal wrist) stratified by sex are provided. Statistically significant, independent correlates of increased pressure pain sensitivity measures were site (neck, dorsal wrist), sex (female), higher waist-hip ratio and poorer mental health. Statistically significant, independent correlates of increased cold pain sensitivity measures were, sex (female), poorer mental health and smoking. ConclusionsThese data provide the most comprehensive and robust sex specific reference values for pressure pain threshold specific to four body sites and cold pain threshold at the dorsal wrist for young adults aged 21–24 years. Establishing normative values in this young age group is important given that the transition from adolescence to adulthood is a critical temporal period during which trajectories for persistent pain can be established. ImplicationsThese data will provide an important research resource to enable more accurate profiling and interpretation of pain sensitivity in clinical pain disorders in young adults. The robust and comprehensive data can assist interpretation of future clinical pain studies and provide further insight into the complex associations of pain sensitivity that can be used in future research.

Reliability of conditioned pain modulation: a systematic review.

A systematic literature review was undertaken to determine if conditioned pain modulation (CPM) is reliable. Longitudinal, English language observational studies of the repeatability of a CPM test paradigm in adult humans were included. Two independent reviewers assessed the risk of bias in 6 domains; study participation; study attrition; prognostic factor measurement; outcome measurement; confounding and analysis using the Quality in Prognosis Studies (QUIPS) critical assessment tool. Intraclass correlation coefficients (ICCs) less than 0.4 were considered to be poor; 0.4 and 0.59 to be fair; 0.6 and 0.75 good and greater than 0.75 excellent. Ten studies were included in the final review. Meta-analysis was not appropriate because of differences between studies. The intersession reliability of the CPM effect was investigated in 8 studies and reported as good (ICC = 0.6-0.75) in 3 studies and excellent (ICC > 0.75) in subgroups in 2 of those 3. The assessment of risk of bias demonstrated that reporting is not comprehensive for the description of sample demographics, recruitment strategy, and study attrition. The absence of blinding, a lack of control for confounding factors, and lack of standardisation in statistical analysis are common. Conditioned pain modulation is a reliable measure; however, the degree of reliability is heavily dependent on stimulation parameters and study methodology and this warrants consideration for investigators. The validation of CPM as a robust prognostic factor in experimental and clinical pain studies may be facilitated by improvements in the reporting of CPM reliability studies.

Evaluation of Clinical Metrology Instrument in Dogs with Osteoarthritis.

BackgroundIn veterinary clinical pain studies, there is a paucity of data on test‐retest variability in Clinical Metrology Instruments (CMIs), and it is unknown whether CMIs should be administered using independent (respondents not permitted to see previous answers) or dependent (respondents shown previous answers) interviewing.ObjectivesTo compare baseline variability in CMIs designed to assess pain in dogs with osteoarthritis, and compare CMI scores using independent (InD) and dependent interviewing (DI) for the Canine Brief Pain Inventory (CBPI) and the Client‐Specific Outcome Measures (CSOM).AnimalsFifty‐one client‐owned dogs with radiographic evidence of osteoarthritis and associated pain.MethodsClinical Metrology Instruments data were collected during 2 randomized, double‐masked, placebo‐controlled, proof of principle pilot studies with parallel treatment groups. Enrolled dogs received either placebo or antinerve growth factor antibody (NV‐01).ResultsAgreement between baseline CMI scores was good (CBPI Pain P = .29, CBPI Interference P = .32, CSOM P = .036, LOAD P = .67, HCPI P = .27), being best for the LOAD (ICC = 0.89). CMI responses collected during independent and dependent interviewing were not statistically different (CBPI Pain P = .33, CBPI Interference P = .28, CSOM P = .42) and showed good agreement. Additionally, dependent interviewing resulted in increased treatment effect sizes.Conclusions and Clinical ImportanceThere is little difference between independent and dependent interviewing, however, dependent interviewing resulted in increased treatment effect sizes. By using dependent interviewing, investigators could increase clinical trial power through minimal change to study design. Further research is warranted to investigate the use of dependent interviewing.

Pain assessment in context: a state of the science review of the McGill pain questionnaire 40 years on.

The McGill pain questionnaire (MPQ) and its later derivative the short form-MPQ have been used widely both in experimental and clinical pain studies. They have been of considerable importance in stimulating research into the perception of pain and now, with the publication of its latest variant, the short form-MPQ-2, it is appropriate to appraise their utility in the light of subsequent research into the nature of pain and the purpose of pain assessment. Following a description of the content and development of the questionnaires, issues of validity, reliability, and utility are addressed, not only in terms of the individual pain descriptors and the scales, but also in terms of methods of quantification. In addition, other methods of pain depiction are considered. In the second part of the review, advances in pain measurement and methodology, in the elucidation of pain mechanisms and pathways, in the psychology of pain, and in the nature of pain behavior are presented and their implications for pain assessment in general and the MPQ family of measures in particular will be addressed. It is suggested that pain assessment needs to be cast in its social context. We need to understand the influences on pain expression using a socio-communication model of pain that recognizes the function of pain and the importance of both innate pain responses and the effects of social learning. The review concludes with recommendations for future use of the MPQ and identifies a number of research challenges which lie ahead.

Who is healthy? Aspects to consider when including healthy volunteers in QST--based studies-a consensus statement by the EUROPAIN and NEUROPAIN consortia.

Clinical and human experimental pain studies often include so-called "healthy" controls in investigations of sensory abnormalities, using quantitative sensory testing (QST) as an outcome measure. However, the criteria for what is considered "healthy" vary among the different studies and between study centers and investigators, partly explaining the high variability of the results. Therefore, several aspects should be considered during inclusion of healthy volunteers in QST-based trials to have homogenous groups of healthy controls with less variability between human experimental studies, so that results are less likely to be false negative or false positive because of subject-related factors. The EUROPAIN and NEUROPAIN consortia aimed to define factors influencing the variability in selection of healthy subjects in QST-based studies before the start of both projects and to give recommendations how to minimize it based on the current literature and expertise of the participants. The present suggestions for inclusion criteria of healthy volunteers into QST-based trials describe a 2-level approach including standardized questionnaires enabling the collection of relevant information on sociodemographic data, medical history, current health status, coping strategies in dealing with pain, and the motivation of the volunteer to participate in the study. These suggestions are believed to help researchers interpret their results in comparison with others and improve the quality of clinical studies including healthy volunteers as controls or in human experimental pain studies. They aim to reduce any confounding factors. Furthermore, the acquired information will allow post hoc analyses of variance for different potential influencing factors.

Differences in the Antinociceptive Effects and Binding Properties of Propranolol and Bupranolol Enantiomers

Recent efforts have suggested that the β-adrenergic receptor (β-AR) system may be a novel and viable therapeutic target for pain reduction; however, most of the work to date has focused on the β2-adrenergic receptor (AR). Here, we compared the antinociceptive effects of enantiomeric configurations of propranolol and bupranolol, two structurally similar nonselective β-blocking drugs, against mouse models of inflammatory and chronic pain. In addition, we calculated in silico docking and measured the binding properties of propranolol and bupranolol for all 3 β-ARs. Of the agents examined, S-bupranolol is superior in terms of its antinociceptive effect and exhibited fewer side effects than propranolol or its associated enantiomers. In contrast to propranolol, S-bupranolol exhibited negligible β-AR intrinsic agonist activity and displayed a full competitive antagonist profile at β1/β2/β3-ARs, producing a unique blockade of β3-ARs. We have shown that S-bupranolol is an effective antinociceptive agent in mice without negative side effects. The distinctive profile of S-bupranolol is most likely mediated by its negligible β-AR intrinsic agonist activity and unique blockade of β3-AR. These findings suggest that S-bupranolol instead of propranolol may represent a new and effective treatment for a variety of painful conditions. PerspectiveThe S enantiomer of bupranolol, a β-receptor antagonist, shows greater antinociceptive efficacy and a superior preclinical safety profile and it should be considered as a unique β-adrenergic receptor compound to advance future clinical pain studies.

Effects of Exercise on Select Biomarkers and Associated Outcomes in Chronic Pain Conditions

Chronic pain is highly prevalent. Current management is challenged by lack of validated objective measures like biological markers. Clinical pain studies employing exercise interventions have evaluated biomarkers; however, it is unclear how exercise impacts biomarkers involved in pain pathways and whether these markers are associated with relevant pain-related outcomes. This systematic review evaluates data from clinical studies employing exercise interventions in chronic musculoskeletal nonmalignant pain conditions in which biomarkers in pain pathways were measured. Published research studies from several databases were examined using the Jadad Scale for assessing the quality of clinical studies. Twelve research studies were reviewed. Jadad scores ranged from 5 to 11 out of 13 points. Inflammatory markers were most commonly measured followed by neurotransmitter-related genes and metabolite-detecting genes. After exercise interventions, changes in biomarkers involved in neurotransmission and inflammation suggest a hypoalgesic exercise effect. Significant biomarker associations were found with pain intensity, fatigue, depression, anxiety, and quality of life. However, there were varying methodologies in the studies reviewed. It remains a question whether biomarkers can be used as objective measures for risk assessment, diagnosis, or evaluation or as surrogate endpoints in chronic pain. Adequate sample sizes, optimal exercise dose determination, study replications, and longitudinal research studies with consistent methodologies are warranted. Regardless, the potential translational value of biomarkers in chronic pain is evident. Advancing nursing research in biomarkers is vital for moving the nursing discipline and clinical chronic pain practice forward. Developing a biobehavioral perspective in chronic pain is also necessary for comprehensive management.

Low-dose solumatrix meloxicam demonstrates low systemic exposure and efficacy in patients with osteoarthitis pain in clinical studies

Low-dose solumatrix meloxicam demonstrates low systemic exposure and efficacy in patients with osteoarthitis pain in clinical studies

Polypharmacy and Chronic Pain: Harm Exposure Is Not All about the Opioids

Individuals seeking treatment for chronic pain in multidisciplinary pain management services are typically already on high doses of pain medications. This cross-sectional cohort study of patients with long-term chronic pain examined profiles of polypharmacy and pain medication-related harm exposure. Multidisciplinary pain management service. The cohort comprised 224 patients taking medications for their pain (1-9 medications; mean = 3.19) with an average pain duration of 10.33 years. The Medication Quantification Scale III (MQS-III) was used to examine potential harm exposure. We generated detriment scores for simple analgesics, adjunctive therapies (e.g., anticonvulsants), opioids, and benzodiazepines. The total MQS-III score was correlated with the total number of medications, but not with age. Almost 10% of patients took medications from all four categories, with most taking medications from two (37%) to three (35%) classes. Eighty percent of patients were taking opioids, accounting for 41% of total MQS scores. Five primary profiles of potential medication-related harms were identified: high harm from all medication categories (N = 12); above average harm from single category-simple analgesics (N = 76), adjunctive analgesics (N = 59), or opioids (N = 46); and above average opioid and benzodiazepine harm (N = 31). While treatment with multiple medications for synergistic or adjunctive effects may assist in medical management of chronic pain, this approach generates increased potential harm exposure. We show that the majority of detriment comes from medications other than opioids and highlight the importance of profiling all pain medications contributing to polypharmacy in clinical pain studies.

Prospective case controlled clinical study of post-endodontic pain after rotary root canal preparation performed by a single operator

ObjectivesThe aim of this study was to assess the influence of the shaping technique on incidence, intensity, duration and type of postoperative pain (PP). MethodsRoot canal treatments were carried out with rotary instrumentation (n=80) during a single-visit, and data about pre-treatment conditions were collected. Patients were given a questionnaire to record the presence or absence of post-endodontic pain, its duration and level of discomfort. A matching patient (same pre-treatment conditions but manual instrumentation) was randomly selected from a pool (n=374) and assigned to the control group. A total of 44 pairs of patients matched completely and were included in the study. Incidence (yes/no) of PP was assessed using Chi-square tests, intensity (mild, moderate, severe) with trend tests and duration (days) with Mann-Whitney U tests. ResultsA significantly greater proportion of the patients in the control group reported pain than did patients in the rotary shaping group (p<0.05). However, pain duration was shorter (p=0.008) in the control group. Differences in level of discomfort were not statistically significant. ConclusionsThe results of this prospective in vivo study suggest that a higher incidence of PP should be expected after manual root canal preparation. However a second major finding of the study is that when present, PP after a rotary canal preparation is expected to last longer. Clinical significanceThere has been an increase in the use of rotary techniques among dentists in recent years. The present study analyses the differences in the incidence and characteristics of postoperative pain that should be expected after rotary canal preparation compared to traditional manual methods that had not been reported yet.

Tough Guys or Sensitive Guys? Disentangling the Role of Examiner Sex on Patient Pain Reports

Experimental and clinical pain studies are conflicting regarding whether individuals report heightened or dampened pain sensitivity in the presence of other men or women. In the present preliminary study, two small medical record reviews of patients admitted for emergency care were conducted to examine the possibility that patients may report differential pain intensity to male and female health care examiners. The study also sought to determine whether these effects are moderated by and, thus, only detectable by examining patients at different pain (debilitation) levels. Pain intensity scores were extracted from two medical record reviews of patients admitted for emergency care (n=64 and n=135, respectively). Pain intensity was measured using an 11-point numerical scale during standard triage assessments and the sex of the examiner was recorded. Mean pain scores reported to male and female emergency staff did not differ in either set of medical records. However, when patients were split between low and high pain levels, male patients reported higher pain scores to male practitioners when experiencing relatively low pain levels, and both male and female patients reported higher pain scores to female practitioners when experiencing relatively high pain levels. The statistical magnitudes of these effects were large, suggesting that this phenomenon may be a pervasive feature in clinical settings and experimental pain studies. These preliminary findings warrant larger-scale investigations of social contextual influences on patient pain reports, which are necessary for creating more standardized protocols for reliably assessing and treating patient pain experiences.

Higher pain perception and lack of recovery from neuropathic pain in females: A behavioural, immunohistochemical, and proteomic investigation on sex-related differences in mice

In experimental and clinical pain studies, the sex of subjects was rarely taken into account, even if nociceptive inputs appear to be processed and modulated by partially distinct neural mechanisms in each sex. In this study we analysed, in male and female mice, behavioural and neuronal responses in developing, maintaining, and recovering from neuropathic pain. Experiments were carried out in adult CD1 mice by using Chronic Constriction Injury (CCI) as neuropathic pain model. We investigated the temporal trend of mechanical nociceptive threshold together with functional recovery of the injured paw, and the immunofluorescence staining of proteins associated with nerve injury and repair and with spinal gliosis, 7 and 121days after CCI. A proteomic analysis on proteins extracted from sciatic nerves was also performed. Male mice showed a gradual decrease of CCI-induced allodynia, the complete recovery occurring 81days after the sciatic nerve ligation. On the contrary, in female mice, allodynia was still present 121days after CCI. Sex-dependent differences also resulted from immunofluorescence experiments: in sciatic nerve, the expression of P0 and Neu200 is greater in neuropathic males than in neuropathic females, suggesting faster nerve regeneration. Proteomic analysis confirmed sex-related differences of proteins associated with nerve regenerative processes. In addition, the reactive gliosis induced by CCI at day 7, as revealed by colocalization of glial fibrillary acidic protein (astrocytes) and CD11b (microglia) with phosphorylated p38, disappeared 121days after CCI in male but not in female mice. These results may have important therapeutic implications for the treatment of neuropathic pain.

Clinical study of acute and chronic pain after temporal craniotomy

Objective To investigate the correlation of chronic pain after surgery and acute pain within 48 h after temporal craniotomy. Methods One hundred and seventy-six patients who underwent surgery through temporal approach were divided into 3 groups and treated with morphine 30 mg (Group M, N = 57), tramadol 1000 mg (Group T, N = 60) and morphine 20 mg + flurbiprofen 200 mg (Group F, N = 59) by patient-controlled intravenous analgesia (PCIA). Postoperative acute pain (resting and movement) was evaluated by Visual Analogue Scale (VAS) at 4, 16, 24 and 48 h respectively. Chronic pain was measured by Short-Form McGill Pain Questionnaire (SF-MPQ) 3 months after surgery. The characteristics of acute and chronic pain, the relationship between them and analgesic effect of 3 kinds of analgesic drugs were analyzed. Results The differences of observed indicators including gender, age, weight and operating time, which might affect the degree of postoperative pain between before and after surgery were not statistically significant (P > 0.05). VAS scores at different time points within 48 h after surgery in each group decreased gradually. The VAS scores in group T (2.91 ± 1.64) was significantly higher than group M (2.19 ± 1.68) and group F (1.71 ± 1.17, P 0.05). The overall incidence rate of chronic pain was 71.02% (125/176), with moderate and severe pain in 15.91% (28/176). Chronic pain and acute postoperative pain severity were positively correlated (resting: rs = 0.171, P = 0.012; movement: rs = 0.190, P = 0.006). The difference of the acute pain (VAS) corresponding to SF-MPQ Ⅱ score > 0 and SF-MPQ Ⅱ score = 0 was statistically significant (P < 0.05). Conclusion The postoperative chronic pain following temporal craniotomy is related to acute pain within 48 h after operation. Effective treatment of early postoperative acute pain may reduce the incidence of chronic pain.

37. A clinical and neurophysiological study of pain in patients with Ehlers Danlos syndrome

Although pain is a frequent complaint in patients with Ehlers Danlos syndrome, its underlying mechanism is still debated, thus limiting the effectiveness of treatment. Although some recent reports suggested that most patients with Ehlers Danlos syndrome suffered from neuropathic pain, no studies have assessed pain associated to this rare condition with the recently proposed diagnostic criteria for neuropathic pain. In this prospective study we aimed at assessing prevalence, clinical features and underlying mechanism of pain in 20 patients with Ehlers Danlos syndrome. All patients underwent a detailed clinical and neurological examination, including the DN4 questionnaires for diagnosing neuropathic pain and the fibromyalgia rapid screening tool. We also recorded the standard nerve conduction study, assessing the non-nociceptive afferent fibres, and laser evoked potentials for assessing nociceptive afferent fibres. We found that clinical examination, DN4 questionnaire, standard nerve conduction study and laser evoked potentials disclosed no abnormalities consistent with a diagnosis of neuropathic pain. Conversely clinical examination showed that most patients suffered of widespread pain, with a positive fibromyalgia rapid screening tool. Our data argue against the view that Ehlers Danlos syndrome-related pain is a neuropathic pain condition, rather our patients suffered of a widespread, fibromyalgia-like pain.

Improvement in low back pain following spinal decompression: observational study of 119 patients

Prospective clinical observational study of low back pain (LBP) in patients undergoing laminectomy or laminotomy surgery for lumbar spinal stenosis (LSS). To quantify any change in LBP following laminectomy or laminotomy spinal decompression surgery. 119 patients with LSS completed Oswestry Disability Index questionnaire (ODI) and Visual Analogue Scale for back and leg pain, preoperatively, 6weeks and 1year postoperatively. There was significant (p<0.0001) reduction in mean LBP from a baseline of 5.14/10to 3.03/10 at 6weeks. Similar results were seen at 1year where mean LBP score was 3.07/10. There was a significant (p<0.0001) reduction in the mean ODI at 6weeks and 1year postoperatively. Mean ODI fell from 44.82 to 25.13 at 6weeks and 28.39 at 1year. The aim of surgery in patients with LSS is to improve the resulting symptoms that include radicular leg pain and claudication. This observational study reports statistically significant improvement of LBP after LSS surgery. This provides frequency distribution data, which can be used to inform prospective patients of the expected outcomes of such surgery.

A new biolistic intradermal injector

We present a novel intradermal needle-free drug delivery device which exploits the unsteady high-speed flow produced by a miniature shock tube to entrain drug or vaccine particles onto a skin target. A first clinical study of pain and physiological response of human subjects study is presented, comparing the new injector to intramuscular needle injection. This clinical study, performed according to established pain assessment protocols, demonstrated that every single subject felt noticeably less pain with the needle-free injector than with the needle injection. Regarding local tolerance and skin reaction, bleeding was observed on all volunteers after needle injection, but on none of the subjects following powder injection. An assessment of the pharmacodynamics, via blood pressure, of pure captopril powder using the new device on spontaneously hypertensive rats was also performed. It was found that every animal tested with the needle-free injector exhibited the expected pharmacodynamic response following captopril injection. Finally, the new injector was used to study the delivery of an inactivated influenza vaccine in mice. The needle-free device induced serum antibody response to the influenza vaccine that was comparable to that of subcutaneous needle injection, but without requiring the use of an adjuvant. Although no effort was made to optimize the formulation or the injection parameters in the present study, the novel injector demonstrates great promise for the rapid, safe and painless intradermal delivery of systemic drugs and vaccines.