Tattoo artists and dental workers have similar musculoskeletal pain patterns

BACKGROUND

Tattoo artists are an understudied population with regards to musculoskeletal (MSK) pain.

AIMS

To explore the characteristics of MSK pain among Israeli tattoo artists and determine whether they are similar to those of dental workers.

METHODS

An online survey including demographics and the Hebrew version of the Extended Nordic Musculoskeletal Questionnaire was disseminated via Israeli social media groups. We directly compared tattoo artists, dental workers and office workers as a reference group.

RESULTS

Altogether, 114 tattoo artists, 161 dental workers and 296 office workers responded. The most prevalent pain sites were lower back (56%), neck (47%) and hand (36%) among office workers; neck (67%), lower back (62%) and upper back (42%) among the dental workers; and lower back (72%), neck (66%) and hand (55%) among tattoo artists. Contrast analysis suggested office workers were less likely to report pain in the previous 12 months compared with dental workers and tattoo artists (adjusted odds ratios [95% confidence intervals]: ORs [95% CIs] for upper limb pain: 1.13 [1.01-1.28], neck pain: 1.3 [1.15-1.47], upper back pain: 1.27 [1.12-1.43] and low back pain: 1.15 [1.02-1.3]). No significant differences were observed between dental workers and tattoo artists (upper limb pain: 1.18 [0.9-1.54], neck pain: 1.06 [0.81-1.4], upper back pain: 1.22 [0.94-1.58] and low back pain: 1.24 [0.95-1.64]).

CONCLUSIONS

Tattoo artists and dental workers have similar MSK pain characteristics and are different from those of office workers. These characteristics are seemingly a direct result of the physical demands associated with their line of work.

Three single leg standing tests for clinical assessment of chronic plantar heel pain syndrome: static stance, half-squat and heel rise

OBJECTIVE

To assess reliability and validity of three single leg standing clinical tests in patients with plantar heel pain syndrome (PHPS).

DESIGN

Cross-sectional reliability study.

PARTICIPANTS

Forty patients diagnosed with PHPS.

MAIN OUTCOME MEASURES

Patients stood on their affected foot in a static stance for up to 30seconds, a half squat for up to 10 repetitions, and a heel rise for up to 10 repetitions. The first sensation of pain (p1) determined the termination of each test, and established a positive test result. The level of p1 was measured using a visual analogue scale (VAS); time or repetitions for each test were recorded. Prior to performing the tests, all patients completed the Foot & Ankle Computerized Adaptive Test to measure functional status (FS).

RESULTS

Detection of p1 in each test showed good reliability for inter- and intrarater assessment (Kappa=0.60 to 0.78 and 0.56 to 0.77, respectively). The intraclass correlation coefficient for the VAS measures was 0.85 to 0.95 for inter-rater assessment and 0.78 to 0.92 for intrarater assessment. However, the Bland and Altman limits of agreement were wide, indicating that these measures were less reliable than the correlation coefficients suggested. Thirty-five patients (88%) experienced a positive pain response to at least one test. Significant correlations were found between the VAS measures in each test and FS (r=0.63 to 0.72).

CONCLUSIONS

The static stance, half squat and heel rise tests were easily implemented, and found to be reliable and valid according to one analysis, yet less reliable with another, for pain provocation and VAS levels in patients with PHPS. All three VAS levels correlated well with FS.

Shape variation of the neural arch in the thoracic and lumbar spine: characterization and relationship with the vertebral body shape

Quantifying the human vertebral geometry is important for accurate medical procedures. We aimed to characterize the neural arch (NA) shape at T1-L5. All T1-L5 dry vertebrae (N = 4,080) of 240 individuals were measured and analyzed by age, gender, and ethnicity. A 3D digitizer was used to measure the dimensions of the spinous (SP) and transverse (TP) processes, vertebral canal (VC), laminae, and isthmus. Most parameters were independent of age and ethnicity, yet greater in males than in females. Isthmus length increases from T1 (9.8 mm) to T12 (19.87 mm) and decreases from T12 to L5 (9.68 mm) with right > left in the thorax and oppositely in the lumbar region. The SP is longer than its thickness both decreasing in the upper thorax (by ca. 4mm), increasing in the lower thoracic and upper lumbar vertebrae (by 7 mm for length and ca. 14.5 mm for thickness) and decreasing again along the lower lumbar vertebrae (both by 8 mm). The TP length decreases at T1-T12 (by 13 mm) and increases at L1-L5 with left > right at T1-L5 (P < 0.003). The laminar length decreases from T1 (8.72 mm) through T5 (4.76 mm) and increases toward L5 (8.4 mm) with right > left at T1-L5 (P < 0.003). The VC is oval-shaped at T1 and T11-L5 (width > length), rounded-shape at T2 and T10 (width = length), and inverted oval-shaped at T3-T9 (length > width). In conclusion, the NA is systematically asymmetrical and dynamic in shape along the thoracic and lumbar spine. The inter-relationship with the vertebral body and articular facets is discussed.

A method for patient-specific evaluation of vertebral cancellous bone strength: in vitro validation

BACKGROUND

In the context of osteoporosis, important determinants of the fracture risk are the apparent strength and stiffness of cancellous bone, as well as its brittleness and energy absorption capacity. Standard medical imaging, however, cannot measure these mechanical properties directly. Consequently, an estimation of the risk for fracture is made by correlating relative density or mineral density at a skeletal site with statistics of fracture occurrence, which provides limited and partial indications on fracture risks. A better method for evaluating the patient-specific mechanical properties of cancellous bone is therefore required.

METHODS

In order to asses the mechanical properties of vertebral cancellous bone, we developed a finite element parametric model of lattice trabecular architecture that, in the future, will be suitable for use with bone imaging modalities. The model inputs are apparent morphological parameters (trabecular thickness and trabecular separation) and the bone mineral density. We conducted uniaxial compression tests on 36 canine vertebral cancellous bone specimens (C7 and L1) to validate model predictions of strength and stiffness in vitro.

FINDINGS

Predictions of strength and stiffness matched the experimental results within relative absolute errors of 17.7% and 12.8%, respectively (average of differences between model-predicted and measured values, divided by the average of measured values). We also employed the model for evaluation of strength and stiffness of human L1 and L5 vertebrae and found mean strength of 1.67 MPa (confidence interval 0.42 MPa) and mean elastic modulus of 190 MPa (confidence interval 50 MPa), which are well within the range of previously reported apparent strength and stiffness properties.

INTERPRETATION

The present model can be used to improve medical imaging-based evaluation of the spine in osteoporotic individuals by providing more specific information on the individual bone's susceptibility to fracture once clinical bone scans will be able to provide more reliable measures of trabecular thickness and separation.