The focus of this project is to evaluate the diagnostic utility of Shear Wave Elastography (SWE) in individuals after routine low back injury and begin an initial investigation of it's ability to effectively guide physical therapy treatment with dry-needling as a relevant treatment intervention.

Specific Aim #1: Evaluate the diagnostic utility of SWE in differentiating individuals with and without LBP. The investigators will also examine the interaction between tissue change and clinical improvement. The investigators hypothesize that individuals with LBP will have higher muscle stiffness (shear modulus) at rest and impaired (lower) stiffness during contraction than individuals without LBP.

Specific Aim #2: Evaluate the effectiveness of dry-needling in decreasing aberrant muscle stiffness in individuals with LBP. The investigators hypothesize that individuals with LBP that receive dry-needling will exhibit larger changes than both individuals with LBP that receive sham dry-needling and than individuals without LBP that receive dry-needling.

Specific Aim #3: Evaluate the effectiveness of dry-needling in decreasing pain and disability in individuals with LBP. The investigators hypothesize that individuals with LBP that receive dry-needling will exhibit larger improvements than individuals with LBP that receive sham dry-needling.

Low back pain (LBP) is the second most frequent reason for health care visits and a leading cause of medical evacuation from theater. Traditional medical diagnosis based on static imaging strategies (e.g. MRI) has failed to improve management of this epidemic. Functional assessment of lumbar musculature using ultrasound imaging provides evidence of clinically relevant deficits in the lumbar multifidus (LM) muscle of patients with LBP, however such procedures are likely only valid within a narrow range of assessment conditions. Shear-Wave Elastography (SWE) is an evolving non-invasive ultrasound imaging technology capable of quantifying tissue stiffness (i.e., elasticity). Originally developed to improve diagnosis of soft tissue tumors, SWE is beginning to be used to as an alternative and more stable method of functional assessment of muscles.

This study will be the second project in a line of research aimed at improving the diagnosis, management, and treatment of patients with LBP using a new structural health monitoring technique called shear wave elastography (SWE). Since no previous studies had used SWE in the lumbar multifidus muscle, the initial project developed the measurement technique to be used with this device. We also established normative parameters, variance, and reliability estimates of SWE outcomes in asymptomatic individuals. A previous study, also performed at AMEDDC&S, found that individuals with LBP whom received dry needling to the lumbar multifidus muscle exhibited a reduction in pain and disability that was associated with an improved ability to contract the lumbar multifidus. The focus of this second project is to evaluate the diagnostic utility of SWE in individuals after routine low back injury and begin an initial investigation of it's ability to effectively guide physical therapy treatment with dry-needling as a relevant treatment intervention.

Inclusion Criteria:

• Between the age of 18 - 65 years
• Read and speak English well enough to provide informed consent and follow study instructions
• Active duty military or DOD beneficiary
• History of prior surgery to the lumbosacral spine
• Received manual therapy, acupuncture, or dry-needling interventions to the lumbosacral spine within the past 4 weeks
• Currently taking anticoagulant medications or those individuals with a medical history of bleeding disorder
• History of systemic inflammatory disease or other serious spinal pathology (e.g. annular tears of the intervertebral disc, spinal stenosis, fracture)
• Known pregnancy and/or inability to lie prone and fully elevate bilateral arms
• Presence of neurogenic LBP defined by either a positive ipsilateral or contralateral straight leg raise (reproduction of symptoms at <45°) or reflex, sensation, or strength deficits in a pattern consistent with nerve root compression
• Medical "red flags" of a potentially serious condition including cauda equina syndrome, major or rapidly progressing neurological deficit, fracture, cancer, infection, or systemic disease

Exclusion Criteria:

• History of prior surgery to the lumbosacral spine
• Received manual therapy, acupuncture, or dry-needling interventions to the lumbosacral spine within the past 4 weeks
• Currently taking anticoagulant medications or those individuals with a medical history of bleeding disorder
• History of systemic inflammatory disease or other serious spinal pathology (e.g. annular tears of the intervertebral disc, spinal stenosis, fracture)
• Known pregnancy and/or inability to lie prone and fully elevate bilateral arms
• Presence of neurogenic LBP defined by either a positive ipsilateral or contralateral straight leg raise (reproduction of symptoms at <45°) or reflex, sensation, or strength deficits in a pattern consistent with nerve root compression
• Medical "red flags" of a potentially serious condition including cauda equina syndrome, major or rapidly progressing neurological deficit, fracture, cancer, infection, or systemic disease