Troy L. Hooper

Thoracic outlet syndrome: a controversial clinical condition. Part 1: anatomy, and clinical examination/diagnosis.

Abstract Thoracic outlet syndrome (TOS) is a frequently overlooked peripheral nerve compression or tension event that creates difficulties for the clinician regarding diagnosis and management. Investigators have categorized this condition as vascular versus neurogenic, where vascular TOS can be subcategorized as either arterial or venous and neurogenic TOS can subcategorized as either true or disputed. The thoracic outlet anatomical container presents with several key regional components, each capable of compromising the neurovascular structures coursing within. Bony and soft tissue abnormalities, along with mechanical dysfunctions, may contribute to neurovascular compromise. Diagnosing TOS can be challenging because the symptoms vary greatly amongst patients with the disorder, thus lending to other conditions including a double crush syndrome. A careful history and thorough clinical examination are the most important components in establishing the diagnosis of TOS. Specific clinical tests, whose accuracy has been documented, can be used to support a clinical diagnosis, especially when a cluster of positive tests are witnessed.

Thoracic outlet syndrome: a controversial clinical condition. Part 2: non-surgical and surgical management

Abstract Background: Proper management of thoracic outlet syndrome (TOS) requires an understanding of the underlying causes of the disorder. A comprehensive examination process, as described in Part 1 of this review, can reveal the bony and soft tissue abnormalities and mechanical dysfunctions contributing to an individuals TOS symptoms. Objective: Part 2 of this review focuses on management of TOS. Conclusion: The clinician uses clinical examination results to design a rehabilitation program that focuses on correcting specific problems that were previously identified. Disputed neurogenic TOS is best managed with a trial of conservative therapy before surgical treatment options are considered. Cases that are resistant to conservative treatment may require surgical intervention. True neurogenic TOS may require surgical intervention to relieve compression of the neural structures in the thoracic outlet. Surgical management is required for cases of vascular TOS because of the potentially serious complications that may arise from venous or arterial compromise. Post-operative rehabilitation is recommended after surgical decompression to address factors that could lead to a reoccurrence of the patients symptoms.

Lower Extremity Fatigue, Sex, and Landing Performance in a Population With Recurrent Low Back Pain

CONTEXT Low back pain and lower extremity injuries affect athletes of all ages. Previous authors have linked a history of low back pain with lower extremity injuries. Fatigue is a risk factor for lower extremity injuries, some of which are known to affect female athletes more often than their male counterparts. OBJECTIVE To determine the effects of lower extremity fatigue and sex on knee mechanics, neuromuscular control, and ground reaction force during landing in people with recurrent low back pain (LBP). DESIGN Cross-sectional study. SETTING A clinical biomechanics laboratory. PATIENTS OR OTHER PARTICIPANTS Thirty-three young adults with recurrent LBP but without current symptoms. INTERVENTION(S) Fatigue was induced using a submaximal free-weight squat protocol with 15% body weight until task failure was achieved. MAIN OUTCOME MEASURE(S) Three-dimensional knee motion, knee and ankle moments, ground reaction force, and trunk and lower extremity muscle-activity measurements were collected during 0.30-m drop vertical-jump landings. RESULTS Fatigue altered landing mechanics, with differences in landing performance between sexes. Women tended to have greater knee-flexion angle at initial contact, greater maximum knee internal-rotation angle, greater maximum knee-flexion moment, smaller knee-adduction moment, smaller ankle-inversion moment, smaller ground reaction force impact, and earlier multifidus activation. In men and women, fatigue produced a smaller knee-abduction angle at initial contact, greater maximum knee-flexion moment, and delays in semitendinosus, multifidus, gluteus maximus, and rectus femoris activation. CONCLUSIONS Our results provide evidence that during a fatigued 0.30-m landing sequence, women who suffered from recurrent LBP landed differently than did men with recurrent LBP, which may increase womens exposure to biomechanical factors that can contribute to lower extremity injury.

Reliability and validation of in vitro lumbar spine height measurements using musculoskeletal ultrasound: A preliminary investigation

BACKGROUND Stadiometry measures total trunk height variations but cannot quantify individual spinal segment height changes. Different methods exist to measure both intervertebral disc and lumbar spine height (LSH) variations but they are either limited by radiation exposure or cost. Musculoskeletal ultrasound could be a valuable alternative to measure spinal segmental height changes as a result of intervention. OBJECTIVE To validate the use of musculoskeletal ultrasound (MSU) and new anatomical landmark references used in assessing inter-mammillary distances (IMD) and LSH changes resulting from lumbar spine traction. METHODS Two unembalmed cadaveric lumbar spines were extracted to assess (1) the reliability and validity of MSU, as compared to caliper, for measuring in vitro IMD and LSH using alternative anatomical landmarks than previously reported, and (2) the reliability of MSU for measuring in vitro IMD and lumbar spine height changes recorded during standardized mechanical traction up to 1.20 cm. RESULTS Intra- and inter-rater reliability of musculoskeletal ultrasound for within and between sessions and for all experimental design, Standard Error ranged from 0.01 to 0.02 and from 0.03 to 0.04 cm for IMDs and LSHs, respectively. Root Mean Square Errors ranged from 1.6 to 6.8% and from 1 to 1.1% for IMDs and LSHs, respectively and mean ICC ranged from 0.98 to 1 for LSH. During traction, mean lumbar spine height measurement change using MSU was 1.15 ± 0.03 cm. Bland and Altman plots demonstrated confidence intervals included in the limits of agreement. Nevertheless, there were significant differences (p< 0.001) for both IMD measurements and lumbar spine height between caliper and ultrasound measurements. Musculoskeletal ultrasound overestimated distances of about 5.5 ± 1.5%. CONCLUSIONS Musculoskeletal ultrasound is reliable and accurate for measuring intersegmental spinal distances and lumbar spine height with an apparent slight overestimation of distances. Based on mean differences, ultrasound technology seems to be valid for measuring lumbar spine height changes and could be suitable for in vivo research.

Volitional Spine Stabilization During a Drop Vertical Jump From Different Landing Heights: Implications for Anterior Cruciate Ligament Injury

CONTEXT Volitional preemptive abdominal contraction (VPAC) during dynamic activities may alter trunk motion, but the role of the core musculature in positioning the trunk during landing tasks is unclear. OBJECTIVE To determine whether volitional core-muscle activation incorporated during a drop vertical jump alters lower extremity kinematics and kinetics, as well as trunk and lower extremity muscle activity at different landing heights. DESIGN Controlled laboratory study. SETTING Clinical biomechanics laboratory. PATIENTS OR OTHER PARTICIPANTS Thirty-two young healthy adults, consisting of 17 men (age = 25.24 ± 2.88 years, height = 1.85 ± 0.06 m, mass = 89.68 ± 16.80 kg) and 15 women (age = 23.93 ± 1.33 years, height = 1.67 ± 0.08 m, mass = 89.68 ± 5.28 kg). INTERVENTION(S) Core-muscle activation using VPAC. MAIN OUTCOME MEASURE(S) We collected 3-dimensional ankle, knee, and hip motions, moments, and powers; ground reaction forces; and trunk and lower extremity muscle activity during 0.30- and 0.50-m drop vertical-jump landings. RESULTS During landing from a 0.30-m height, VPAC performance increased external oblique and semitendinosis activity, knee flexion, and knee internal rotation and decreased knee-abduction moment and knee-energy absorption. During the 0.50-m landing, the VPAC increased external oblique and semitendinosis activity, knee flexion, and hip flexion and decreased ankle inversion and hip-energy absorption. CONCLUSIONS The VPAC performance during landing may protect the anterior cruciate ligament during different landing phases from different heights, creating a protective advantage just before ground contact and after the impact phase. Incorporating VPAC during high injury-risk activities may enhance pelvic stability, improve lower extremity positioning and sensorimotor control, and reduce anterior cruciate ligament injury risk while protecting the lumbar spine.

The Effects of Volitional Preemptive Abdominal Contraction on Postural Control Responses in Healthy Subjects

To investigate the effect of volitional preemptive abdominal contraction by using an abdominal bracing maneuver (ABM) on postural control responses.

Musicians injuries: Upper quarter motor control deficits in musicians with prolonged symptoms - A case-control study

STUDY DESIGN Case-control study. BACKGROUND A large number of student and professional musicians are affected by long term playing related musculoskeletal disorders (PRMSDs) during their career, with prevalence rates above 80%. OBJECTIVE To investigate if there were differences between musicians with and without prolonged symptoms of upper quarter PRMSDs in the presence of: (1) scapular dyskinesis; (2) cervical motor control and endurance deficits. METHODS Seventy-two musicians (24 males; 48 females) were matched based on sex, type of instrument and average hours played per week and assigned to one of two groups: A symptomatic group (mean age 23.3 ± 8.2 years) with history of prolonged PRMSDs (constant symptoms lasting more than one week) during the past year; and a control group (mean age 25 ± 10.5 years) with no history of PRMSDs lasting more than one week. Musicians completed a questionnaire and underwent clinical testing for the presence of scapular dyskinesis and cervical motor control and endurance deficits using the following tests: (1) cervical flexor endurance test; (2) scapular dyskinesis test; and (3) craniocervical flexion test. Assessor blinding as to group assignment was ensured. RESULTS Participants in the symptomatic group presented with a statistically significant higher prevalence of positive scapular dyskinesis (P < .0001; OR = 7.8) and lower scores for the craniocervical flexion test (P < .0001). CONCLUSION Musicians with prolonged symptoms of PRMSDs presented with higher prevalence of scapular and cervical motor control deficits detected by standard clinical tests when compared to the control group. LEVEL OF EVIDENCE Therapy, level 4. CLINICALTRIALS. GOV IDENTIFIER NCT02267395.

The Effect of Current Low Back Pain on Volitional Preemptive Abdominal Activation During a Loaded Forward Reach Activity

A volitional preemptive abdominal contraction (VPAC) supports trunk stability during functional activity. Pain‐free individuals can sustain VPAC during function, but such has not been reported for individuals with current low back pain (cLBP).

The Effect of Distractive Function on Volitional Preemptive Abdominal Contraction During a Loaded Forward Reach in Normal Subjects.

Volitional preemptive abdominal contraction (VPAC) is used to protect the spine and prevent injury. No published studies to data have examined the effect of distraction on VPAC use during function.