Chronic whiplash and central sensitization; an evaluation of the role of a myofascial trigger points in pain modulation

<p>Abstract</p> <p>Objective</p> <p>it has been established that chronic neck pain following whiplash is associated with the phenomenon of central sensitization, in which injured and uninjured parts of the body exhibit lowered pain thresholds due to an alteration in central pain processing. it has furthermore been hypothesized that peripheral sources of nociception in the muscles may perpetuate central sensitization in chronic whiplash. the hypothesis explored in the present study was whether myofascial trigger points serve as a modulator of central sensitization in subjects with chronic neck pain.</p> <p>Design</p> <p>controlled case series.</p> <p>Setting</p> <p>outpatient chronic pain clinic.</p> <p>Subjects</p> <p>seventeen patients with chronic and intractable neck pain and 10 healthy controls without complaints of neck pain.</p> <p>Intervention</p> <p>symptomatic subjects received anesthetic infiltration of myofascial trigger points in the upper trapezius muscles and controls received the anesthetic in the thigh.</p> <p>Outcome measures: pre and post injection cervical range of motion, pressure pain thresholds (ppt) over the infraspinatus, wrist extensor, and tibialis anterior muscles. sensitivity to light (photophobia) and subjects' perception of pain using a visual analog scale (vas) were also evaluated before and after injections. only the ppt was evaluated in the asymptomatic controls.</p> <p>Results</p> <p>immediate (within 1 minute) alterations in cervical range of motion and pressure pain thresholds were observed following an average of 3.8 injections with 1–2 cc of 1% lidocaine into carefully identified trigger points. cervical range of motion increased by an average of 49% (p = 0.000) in flexion and 44% (p = 0.001) in extension, 47% (p = 0.000) and 28% (p < 0.016) in right and left lateral flexion, and a 27% (p = 0.002) and 45% (p = 0.000) in right and left rotation. ppt were found increased by 68% over the infraspinatus (p = 0.000), by 78% over the wrist extensors (p = 0.000), and by 64% over the tibialis anterior (p = 0.002). among 11 subjects with photophobia, only 2 remained sensitive to light after the trigger point injections (p = 0.033). average vas dropped by 57%, from 6.1 to 2.6 (p = 0.000). no significant changes in ppt were observed in the control group following lidocaine infiltration of the thigh.</p> <p>Conclusion</p> <p>the present data suggest that myofascial trigger points serve to perpetuate lowered pain thresholds in uninjured tissues. additionally, it appears that lowered pain thresholds associated with central sensitization can be immediately reversed, even when associated with long standing chronic neck pain. although the effects resulting from anesthesia of trigger points in the present study were temporary, it is possible that surgical excision or ablation of the same trigger points may offer more permanent solutions for chronic neck pain patients. further study is needed to evaluate these and other options for such patients.</p

Coupled Interannual Variability of Wind and Sea Surface Temperature in the Caribbean Sea and the Gulf of Mexico

This work describes dominant patterns of coupled interannual variability of the 10-m wind and sea surface temperature in the Caribbean Sea and the Gulf of Mexico (CS&GM) during the period 1982-2016. Using a canonical correlation analysis (CCA) between the monthly mean anomalies of these fields, four coupled variability modes are identified: the dipole (March-April), transition (May-June), interocean (July-October), and meridional-wind (November-February) modes. Results show that El Nino-Southern Oscillation (ENSO) influences almost all the CS&GM coupled modes, except the transition mode, and that the North Atlantic Oscillation (NAO) in February has a strong negative correlation with the dipole and transition modes. The antisymmetric relationships found between the dipole mode and the NAO and ENSO indices confirm previous evidence about the competing remote forcings of both teleconnection patterns on the tropical North Atlantic variability. Precipitation in the CS and adjacent oceanic and land areas is sensitive to the wind-SST coupled variability modes from June to October. These modes seem to be strongly related to the interannual variability of the midsummer drought and the meridional migration of the intertropical convergence zone in the eastern Pacific. These findings may eventually lead to improving seasonal predictability in the CS&GM and surrounding land areas.Programa Nacional de Posgrados de Calidad of the Consejo Nacional de Ciencia y Tecnologia of Mexico; CONACYT-SENER-Hidrocarburos Project [201441]6 month embargo; published online: 20 June 2019This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Detrital Shocked Zircon Provides First Radiometric Age Constraint of <1472 Ma for the Santa Fe Impact Structure, New Mexico, USA

Impact structures are prone to erosion, burial and tectonic deformation. The Santa Fe impact structure in New Mexico contains shatter cones and shocked quartz, but is highly tectonized and eroded; estimates of the impact age (1200-300 Ma) and size (6-13 km) are poorly constrained. Here we report the first occurrence of shock-twinned zircon identified both in modern sediments and bedrock at the Santa Fe impact structure. Zircon {112} twin lamellae are considered diagnostic evidence of shock deformation and have been identified at several impact structures including Vredefort, Sudbury, Ries, Rock Elm, and in lunar impact breccia. A total of 6619 grains from fifteen sediment samples and two rock samples were surveyed; seven shocked grains were identified (7/6619 = 0.1%). One shocked zircon was identified in a biotite schist shatter cone. Five of seven shocked zircon grains were EBSD mapped; three were analyzed with multiple SIMS spots. EBSD mapping revealed {112} deformation twin lamellae in each of the five zircon grains. U-Pb geochronology for three of the shocked zircon grains yield crystallization ages from 1715+/-22 to 1472+/-35 Ma. LA-ICPMS U-Th-Pb analysis of detrital zircon grains from five samples yielded Paleoproterozoic (1800-1600 Ma) and Mesoproterozoic (1500-1300 Ma) ages. We reveal the first confirmed shocked zircon at the Santa Fe structure. Zircon is the third shocked mineral identified at this site, in addition to xenotime and quartz]; the {112} twin lamellae indicate that exposed bedrock may have experienced shock pressures up to ~20 GPa. The 1472+/-35 Ma age determined from a shock-twinned zircon is the first reliable maximum impact age constraint based on analysis of shocked material and extends the window for the Santa Fe impact event into the Mesoproterozoic