Effect of Opioid Use on Results of Interventional Back Pain Management on Patients With Suspected Face-mediated Chronic Back Pain.

BACKGROUND: Preoperative exposure to opioids has recently shown to be associated with poor outcomes after elective major surgery, but little is known as to how pretreatment opioid use affects results of interventional back pain management. OBJECTIVE: We aimed to determine the effect of pretreatment opioid use on outcomes after interventional pain management procedures on patients with chronic back pain. STUDY DESIGN: A retrospective study. SETTING: Department of Physical Medicine and Rehabilitation at Satakunta Central Hospital (Satasairaala), Finland. METHODS: A high-volume, single-center, quality register analysis was performed on patients who underwent interventional pain management for suspected facet-mediated chronic back pain as a part of a multidisciplinary pain management program. Chronic opioid use was defined as having a concurrent opioid prescription for 90 days. RESULTS: A total of 797 patients underwent an intervention during the study period from August 1, 2019 through December 31, 2020. Pretreatment opioid use was present in 262 patients (33%). Patients with chronic back pain using opioids reported significantly more pain and discomfort before treatment as well as lowered working ability. Facet joint medial branch blocks resulted in significant improvement for both groups directly after the treatment as well as at 2-hours follow-up. However, the nonopioid group reported significantly more improvement at 2-days follow-up as well as at one month follow-up compared to opioid users. Opioid users reported nearly the same pain level at one-month follow-up as they did before treatment. LIMITATIONS: As a single-center analysis, these data may not be generalizable to other institutions. A retrospective study may include inevitable bias. The disease processes themselves may possibly predispose patients to different degrees of opoid use. Although we have identified preoperative opioid use as a risk factor for treatment failure, we were unable to determine the size of the association based on our statistical analysis and sample size. Pain intensity evaluation using the visual analog scale is inevitably subjective. CONCLUSION: Pretreatment opioid use is associated with greater pain discomfort, impairment, and reduced functional ability, as well as poorer long-term effect of interventional back pain treatment at one-month follow-up. In our study, opioid users reported the same positive effects of facet joint nerve blocks immediately after the treatment and 2 hours after the treatment, but a significantly smaller effect at one-month follow-up. This could indicate that opioid use may diminish the effects of pain treatments by affecting relearning, behavioral changes, and central pain modulation. These findings may help providers understand the effect of pretreatment opioid use on patient care, and its implications on hospital and societal costs.

Critical neural targets for (the level of) human consciousness: Arousal arrest and unconsciousness after sumatriptan administration.

BACKGROUND: Insufficient understanding of the mechanisms of consciousness can make unconsciousness a diagnostic challenge, directly effecting the treatment and the outcome of the patient. Consciousness is a product of brainstem arousal (wakefulness, the level of consciousness) and cortical information integration (awareness, the contents of consciousness). The thalamus serves as a critical hub in the arousal pathway. The nuclei within the internal medullary lamina, together with the associated thalamocortical connections, have been implicated as being especially important for human consciousness. CASE STUDY: A 17-year old male migraineur developed a sudden episode of unconsciousness after receiving a single dose of intranasal sumatriptan for the treatment of prolonged migraine-associated symptoms. Diffusion-weighted magnetic resonance imaging revealed a small bilateral thalamic infarction affecting the centromedian and parafascicular nuclei and the associated non-specific thalamocortical connections as the likely reason for the impairment of consciousness. With the exception of occasional fatigue due to a persistent lesion on the left thalamus, the patient experienced full recovery. Corresponding to the injury, diffusion tensor tractography imaging revealed a distinctive defect on the thalamocortical fibres originating from the left centromedian/parafascicular nuclei complex. CONCLUSIONS: The presented case offers an outstanding example of the importance of the arousal system and non-specific thalamocortical connectivity for normal waking consciousness.

Novel wireless electroencephalography system with a minimal preparation time for use in emergencies and prehospital care.

BACKGROUND: Although clinical applications such as emergency medicine and prehospital care could benefit from a fast-mounting electroencephalography (EEG) recording system, the lack of specifically designed equipment restricts the use of EEG in these environments. METHODS: This paper describes the design and testing of a six-channel emergency EEG (emEEG) system with a rapid preparation time intended for use in emergency medicine and prehospital care. The novel system comprises a quick-application cap, a device for recording and transmitting the EEG wirelessly to a computer, and custom software for displaying and streaming the data in real-time to a hospital. Bench testing was conducted, as well as healthy volunteer and patient measurements in three different environments: a hospital EEG laboratory, an intensive care unit, and an ambulance. The EEG data was evaluated by two experienced clinical neurophysiologists and compared with recordings from a commercial system. RESULTS: The bench tests demonstrated that the emEEG system's performance is comparable to that of a commercial system while the healthy volunteer and patient measurements confirmed that the system can be applied quickly and that it records quality EEG data in a variety of environments. Furthermore, the recorded data was judged to be of diagnostic quality by two experienced clinical neurophysiologists. CONCLUSIONS: In the future, the emEEG system may be used to record high-quality EEG data in emergency medicine and during ambulance transportation. Its use could lead to a faster diagnostic, a more accurate treatment, and a shorter recovery time for patients with neurological brain disorders.

Head repositioning accuracy and posturography related to cervical facet nerve blockade and spinal manipulative therapy in healthy volunteers: a time series study.

OBJECTIVE: The aim of the study was to investigate if changes in head repositioning accuracy (HRA), and standing balance could be evoked by unilateral facet nerve blockade (FNB) or spinal manipulative therapy (SMT). METHODS: This time series research study (n = 6) was chosen because of the viability of the experiment, sample characteristics, and small sample size. Cervical proprioceptive functions were assessed by exploring HRA and static posture by computerized posturography. All participants were subjected to 2 interventions, unilateral FNB using local anesthetic and SMT. RESULTS: No significant trends were seen in the subjects over the period of the study. All measurements were taken approximately 3 weeks apart. Visually, it was detected that most of subjects appeared to be greatly affected by the FNB, thus, increasing their deviation from the center point of measurement in extension and flexion movements. When comparing the changes with respect to the baseline after SMT, all subjects showed some differences, though there was a great deal of variation between the subjects. These trends were also seen when comparing the changes from baseline measurements to those after FNB. CONCLUSIONS: Data from this time series research design suggest there was no uniform response to unilateral FNB or to SMT. However, differences indicate that there may be important effects of unilateral FNBs for some of the HRA aspects measured. Balance testing using computerized posturography did not show clear differences between baseline assessments and interventions. A future larger clinical study to detect changes in HRA evoked by unilateral FNB or SMT appears feasible.

Improvement after chiropractic care in cervicocephalic kinesthetic sensibility and subjective pain intensity in patients with nontraumatic chronic neck pain.

OBJECTIVE: The objective of this study was to examine alteration in head repositioning accuracy (HRA), range of motion, and pain intensity in patients with chronic cervical pain syndrome without a history of cervical trauma. METHODS: The study was a prospective, randomized, controlled trial. Forty-one patients with chronic cervical pain were randomly assigned to either a control group or a chiropractic treatment group. All patients were clinically examined, given general information on cervical pain, and provided with training instructions based on the clinical evaluation. The treatment included sessions with high-velocity and low-amplitude manipulation, proprioceptive neuromuscular facilitation, ischemic compression of myofascial trigger points, and spinal rehabilitation exercises aiming to normalize cervical range of motion (CROM) and HRA. Subjective pain intensity, cervical kinesthetic sensibility, and CROM were recorded before and after the study period. RESULTS: There was no difference between the treatment patients and the control subjects at the beginning with regard to age, sex, subjective pain intensity, range of motion, and HRA. At the 5-week follow-up, the treatment patients showed significant reductions in pain and improvement of all HRA aspects measured whereas the control subjects did not show any reduction in pain and improvement in only one HRA aspect. No significant difference was detected in CROM. CONCLUSIONS: The results of this study suggest that chiropractic care can be effective in influencing the complex process of proprioceptive sensibility and pain of cervical origin. Short, specific chiropractic treatment programs with proper patient information may alter the course of chronic cervical pain.

Somatosensory evoked potentials following stimulation of digital nerves.

Cortical and spinal somatosensory evoked potentials (SEP) were recorded in healthy individuals following stimulation of digits I, III, and V with an intensity below discomfort level. Peak latency of the earliest cortical negativity (N1) was found to be the most consistent and easily measured parameter, whereas a spinal potential (Cv) was not elicited in all subjects. Descriptive statistics, Student's paired t-test as well as simple and multiple regression, were used for computer analysis of N1 and Cv peak latencies and central conduction time. The results show a strong correlation between the peak latencies of spinal and cortical potentials and height and arm length of the subjects, with a mild but significant correlation with age. Using multiple regression for N1 and Cv latencies significantly improved the standard deviation. The data may provide reference values for neurophysiological evaluation of patients with cervical spine disorders.