Lumbar Strain

Original Editors - Pieter Jacobs

Top Contributors - Bo Hellinckx, Hannah Willocx, Sarah Harnie, Lynn Leemans, Kim Jackson, Elodie Baele, Lilian Ashraf, Nel Breyne, Wanda van Niekerk, Lucinda hampton, Olajumoke Ogunleye, WikiSysop, 127.0.0.1, Admin, Rachael Lowe and Naomi O'Reilly - Bo Hellinckx - Lynn Leemans - Nel Breyne - Sarah Harnie

Definition/Description

Mechanical back strain is a subtype of back pain where the aetiology is the spine, intervertebral discs, or the surrounding soft tissues. Lumbar strain accounts for 70% of mechanical low back pain.

This article will focus on muscular lumbar back sprain ie stretch injury or tear of paraspinal muscles and tendons in the low back (much of the knowledge of lumbar strain is extrapolated from peripheral muscle strains).

• In strains, the muscle is subjected to an excessive tensile force leading to the overstraining of the myofibres and consequently to their rupture near the myotendinous junction.
• Acute mechanical back strains may be triggered by physical or non-physical activity, with lifting being the most commonly recalled event. However, one-third of patients may not necessarily remember an inciting incident.

Clinically Relevant Anatomy

The lumbar spine consists of a remarkable combination of 5 strong vertebrae; multiple bony elements linked by joint capsules; flexible ligaments/tendons; large muscles; highly sensitive nerves. It is designed to be incredibly strong, protecting the highly sensitive spinal cord and spinal nerve roots. At the same time, it is highly flexible, providing mobility in many different planes including flexion, extension, side bending, and rotation

Lumbar strain can originate in the following muscles: M. erector spinae (M. iliocostales, M longissimus, M. spinalis) M semispinales, Mm multifidi, Mm rotatores M. quadratus lumborum M. Serratus Posterior.

Etiology

Strains are defined as tears (partial or complete) of the muscle-tendon unit.

• Muscle strains and tears most frequently result from a violent muscular contraction during an excessively forceful muscular stretch from lifting heavy objects or sudden twisting motions.
• Any posterior spinal muscle and its associated tendon can be involved, although the most susceptible muscles are those that span several joints.
• Acute and chronic lumbar strain pain presentation: Acute pain is most intense 24 to 48 hours after injury. Chronic strains are characterized by continued pain attributable to muscle injury.

Epidemiology

Greater than 80% of people will suffer from low back pain during their lifetime. The global point prevalence of low back pain is 12 to 33%. There is a higher prevalence among women and people ages 40 to 80 years old. Exact numbers regarding the international frequency of low back injuries are not known.

• In the United States 7-13% of all sports injuries in intercollegiate athletes are low back injuries. The most common back injuries are muscle strains (60%) and disc injuries (7%).
• In France over 50% of French individuals aged 30-64 years had experienced at least 1 day of LBP over the previous 12 months. 17% had suffered LBP for over 30 days in the same 12-month period.
• In an African study, the mean LBP point prevalence among adults was 32%, with an average 1-year prevalence of 50% and an average lifetime prevalence of 62%

Characteristics/Clinical Presentation

Acute mechanical back strains may be triggered by physical or non-physical activity, with lifting being the most commonly recalled event. However, one-third of patients may not necessarily remember an inciting incident.

• The clinical presentation includes pain in the lumbar muscles or nonspecific pain.
• The pain could be exacerbated during standing and twisting motions, with active contractions and passive stretching of the involved muscle increasing the pain.
• Other symptoms are point tenderness, muscle spasm, possible swelling in and around the involved musculature, a possible lateral deviation in the spine with severe spasm and a decreased range of motion.

Differential Diagnosis

• Spondylosis

• Disc herniation

• Compression fracture

• Spinal stenosis

•  Spondylolisthesis 

• Ankylosing spondylitis 

Diagnostic Procedures

In the absence of the Red Flags, no laboratory or radiographic studies are necessary to diagnose or manage mechanical back strains in the acute setting.

• Inflammatory biomarkers, eg erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are helpful for risk stratification of patients with risk factors for infectious spinal pathology or malignancy but have no neurologic deficits on examination.
• Routine imaging for mechanical back strains is not recommended, as many may have incidental abnormal findings unrelated to their pain.
• More advanced imaging is needed in trauma, failure of conservative management, worsening of symptoms, and new neurologic deficits. Plain radiographs and computed tomography are useful when suspecting fractures.

Examination

Lumbar Assessment see link.

Medical Intervention

Management of mechanical back strains depends on the chronicity of symptoms, the patient's comorbidities, and the specific aetiology. The American College of Physicians published an updated guideline in 2017 with recommendations regarding non-invasive options for treating low back pain.

First-line nonpharmacologic therapy:

• For Acute low back pain includes spinal manipulation, acupuncture, massage, and superficial heat application, while first-line pharmacologic therapy for acute low back pain is nonsteroidal anti-inflammatory drugs and muscle relaxants. According to the clinical policy by the American College of Emergency Physicians, opioids should not be routine pharmaceutical therapy but saved for those whose pain is severe or uncontrolled with other medications.
• For chronic low back pain, non-pharmacologic approaches were recommended as the first-line agents, including exercise, tai-chi, yoga, multidisciplinary rehabilitation, spinal manipulation, acupuncture, psychotherapy, low-level laser therapy, and electromyogram biofeedback. Nonsteroidal anti-inflammatory drugs were again the first-line pharmacologic agents recommended, followed by tramadol and duloxetine as the second-line treatments. Recommendations for opioid therapy are only if the previously mentioned therapies failed and based on an individualized decision to determine if the benefit outweighs the risk.

Physical Therapy Management

Education: Interventions that may aid in injury prevention

• Stretching exercises at the workplace, appropriate rest breaks, and ergonomic modifications. Ergonomic modifications refer to adaptations in the work environment to reduce the physical stress of the employees.
• Educating patients regarding the importance of maintaining proper posture and correct lifting techniques may aid in prevention. Regular physical activity
• Smoking cessation
• Weight loss for obese patients
• Resuming normal physical activity (recent studies have found that continuing ordinary activities within the limits permitted by the pain leads to more rapid recovery than bed rest).

Techniques

Cold Therapy: In the acute phase of a lumbar strain Cold therapy should be applied (for a short period up to 48 h)to the affected area to limit the localized tissue inflammation and oedema.

TENS and Ultrasound: TENS and ultrasound are often used to help control pain and decrease muscle spasms

Stretching: Mild stretching exercises along with limited activity. Stretching Exercises below

• 
  Single and double knee to chest Lie down on your back with your knees bent and your heels on the floor. Pull your knee or knees as close as you can to your chest, and hold the pose for 10 seconds. Repeat this 3 to 5 times. 
• Back stretch Lie on your back, hands above your head. Bend your knees and, keeping your feet on the floor, roll your knees to one side, slowly. Stay at one side for 10 seconds and repeat 3 to 5 times.

• Press up Begin by laying flat on the ground (face down). When doing this exercise it is important to keep the hips and legs relaxed and in contact with the floor. Keep your hands in line with your shoulders. Inhale, then exhale and press up using your hands keeping the lower half of your body relaxed. Hold until you need to inhale, then move down, lay flat on the ground to rest, and repeat ten times.

• Kneeling lunge(stretching iliopsoas)
• Stretching piriformis
• Stretching quadratus lumborum

Soft Tissue Manipulation: Soft tissue manipulation was found to decrease pain and improve ROM.

• Massage
• Strengthening Exercises: Progression of strengthening exercises should begin once the pain and spasm are under control. The muscles requiring the most emphasis are the abdominals, especially the obliques, the trunk extensors and the gluteals. Placing all of the emphasis on rehabilitation specifically on the injured muscle is not beneficial. Training the core stability is an important part  in the treatment of a lumbar strain  and for the further  prevention of low back pain.  

As with all spinal injuries, posture and body mechanics should be assessed and corrected as needed.

Prognosis

A  Lumbar strain improves within 2 weeks. Normal functions are restored after 4 – 6 weeks.