Osteopathic Manipulative Treatment: Muscle Energy Procedure - Lumbar Vertebrae

Anatomy and Physiology

Discussion of the various mechanisms of muscle energy exceeds the scope of this article. Instead, the focus will be on MET with post-isometric relaxation for treating lumbar dysfunctions. This technique entails positioning the patient toward the barrier and resisting the physician as they push toward freedom. This motion triggers the Golgi tendon reflex, facilitating relaxation and potentially articulating the treated segment.[8][10]

Understanding the functional anatomy of the lumbar region is important. The lumbar spine is made up of 5 vertebrae that form a gentle lordotic curve above the sacrum. Compared to other vertebral segments, the lumbar region is larger in size, which gives it stability while still allowing for movement. It is important to note that the main function of the lumbar spine is to facilitate movements of the trunk.[11][12]

The vertebral body is larger than the other spinal vertebrae, and unlike the other vertebrae, the lumbar vertebrae do not have any costal facets nor a transfer foramina. In between each vertebra are intervertebral discs that dissipate heavy loads. Each disc is composed of a compressible nucleus pulposus surrounded by layers of an annulus of collagen fibers. The posterior aspect of the discs is thinner than the anterior. This aspect carries a greater risk of disc rupture and herniation.[13] The vertebral nerve on the posterior longitudinal ligament becomes irritated during the initial stages of a disc rupture, which causes lower back pain. 

The pedicles and the transverse and articular processes are important posterior elements of the lumbar spine. Positioned on the superior third of the posterior surface of the vertebral body, the pedicle connects the posterior elements to the vertebral body. Each pedicle extends laterally to form the transverse process, which can be located directly lateral to its respective spinous process during a physical examination. Additionally, the segment features both superior and inferior articular processes, with the inferior process facing caudally and laterally from the pedicle, while the superior process faces medially.

The lumbar facet joints are thought to be a source of low back pain. The facet is innervated by the dorsal rami above and below the joint.[14] Pain at the facet may be referred to the lower extremities. Finally, the lamina will start from the pedicle, travel caudally and medially, and meet other lamina at midline.

Ligamentous structures provide stability to the lumbar vertebra. The ligamentum flavum attaches each pedicle and lamina to the next and makes up the posterolateral boundary to the neural foramen. Hypertrophy of the ligamentum flavum can cause potential nerve root compression and can commonly be injured with excessive spinal flexion. The interspinous ligament allows the thoracolumbar fascia and multifidus to be anchored to the facet joint capsule, which also acts as a central support system for the lumbar spine. The anterior longitudinal ligament runs along the anterior surface of the vertebral body. The posterior longitudinal ligament runs on the posterior aspect of the vertebral body. As this ligament is half its original width at the level of L5, it is much weaker in the lumbar spine than in superior segments of the spine.[15] The iliolumbar ligament is attached to the transverse process of L4 and L5 and extends to the anterior edge of the iliac crest. Notably, it may be one of the first ligaments to become tender to palpation during lumbosacral strain.[16]

Understanding the muscular anatomy is crucial in lumbar spine treatment, as these muscles play a vital role in correcting somatic dysfunctions. Notably, the first 3 lumbar vertebrae are associated with the diaphragm; the left crura of the diaphragm attaches to L1 and L2, while the right crura connects from L1 to L3. Additionally, the lumbar vertebrae contribute to the origin of the erector spinae muscles. The psoas muscle, a primary hip flexor, attaches from L1 to L4 and joins the iliacus muscle to insert at the lesser trochanter of the femur. Asymmetric tension in the psoas muscles often contributes to back pain.[17] Moreover, the multifidus muscle plays a crucial role in supporting the lumbar spine during various activities, including standing, sitting, walking, trunk motion, and lifting. Dysfunction in these muscles is another common cause of low back pain.

Indications

Indications for MET of the lumbar vertebrae include acute or chronic low back pain, lumbar muscle spasm, decreased range of motion, or lumbar spine stiffness.[2][9] Through viscerosomatic reflexes, MET of the lumbar vertebrae is also indicated for prostate, descending colon, sigmoid colon, rectum, and lower extremities pathologies. Overall, MET is a safe procedure with a low risk of injury when it is performed correctly.

Contraindications

Contraindications for MET of the lumbar spine include recent surgery at the lumbar region, significant injury of the lumbar spine including lumbar spinal fracture or acute cord compression, cauda equina syndrome, lumbar spinal malignancy, metastasis of primary malignancy to the lumbar spine, osteomyelitis of the lumbar spine, and severe osteoporosis. Additionally, there is a relative contraindication to performing MET on intensive care unit patients with low vitality. The addition of excessive muscle force may further exacerbate this population's compromised condition. For patients with lower vitality levels, using MET through alternative modalities, such as reciprocal inhibition, is advisable. Furthermore, MET is contraindicated for individuals unable to follow verbal directions.[18][19]

Equipment

The equipment utilized for MET includes a padded treatment table or a comfortable surface for the patient to sit or lie on, positioned at an appropriate height for the clinician.

Personnel

Healthcare professionals trained in osteopathic manipulative medicine.

Preparation

Before beginning treatment, clinicians recognize that a precise diagnosis is essential for success. Lumbar somatic dysfunctions can be categorized into type 1 (neutral group dysfunctions) or type 2 (non-neutral dysfunction) based on Fryette's law of spinal mechanics.[8] A straightforward method of determining the diagnosis involves comparing the position of the transverse process bilaterally. The direction of rotation is indicated by the side with the posterior transverse process.

Clinicians instruct the patient to flex forward and extend backward until the segment level to observe any changes in the position of the transverse process. If the transverse process becomes more level in flexion or extension, it indicates a flexed or extended somatic dysfunction (type 2). Conversely, if the segments remain unleveled, it is considered a neutral dysfunction (type 1). Typically, in type 1 (neutral) dysfunction, a group of segments are sidebent and rotated in opposite directions. For instance, neutral rotated right and side bent right (N RrSl); in type 2 (non-neutral dysfunction), the segments are side-bent and rotated in the same direction.

Technique or Treatment

MET applied to the lumbar spine can decrease low back pain intensity.[20] Various approaches exist for treating the lumbar spine with MET. Below is a simple approach for performing it in a seated position. Alternatively, methods may involve lying down in lateral recumbent positions and engaging either the side bending or rotational component as the activating force. Despite differences in technique, the overall treatment principles remain consistent during post-isometric relaxation: position the patient toward the barrier and instruct them to push against the clinician's resistance toward freedom.[8] 

The following steps describe the treatment for a neutral, side bent left and rotated right diagnosis (NSlRr, type 1):

• Step 1: The patient is instructed to sit straddling a treatment table near the end so that their back faces the physician, who may stand beside or behind them. The patient then crosses their arms across their chest.

• Step 2: The physician positions themselves behind the patient and places their left axilla on their left shoulder. The physician's left hand makes contact with the patient's right shoulder, while the left arm is crossed anteriorly to the patient's chest.

• Step 3: Using their right hand, the physician palpates the dysfunctional lumbar segment and maintains this position throughout the treatment to assess the restrictive barrier and monitor tissue release in the lumbar spine.

• Step 4: The physician initiates right-side bending by applying downward pressure to the patient's right shoulder. Subsequently, the patient is rotated to the left, down to the level of the lumbar spine segment, by the physician pulling the patient's right shoulder anteriorly until a restrictive barrier is felt. This positioning places the patient's lumbar segment in a rotated left and side-bent right position, contrary to the patient's lumbar spine diagnosis. As a result, the treated segment is positioned at its restrictive barrier, allowing for correction of segmental restriction.

• Step 5: While maintaining the restrictive barrier, the physician instructs the patient to "attempt to sit in a neutral position," "turn their body to the right against the thumb placed on their back," or "push their left shoulder toward the ceiling." These instructions aim to engage specific muscle groups and apply a gentle counterforce against the physician. Essentially, the patient rotates right and side-bends left against the isometric resistance provided by the physician, maintaining the treatment position. The patient is advised to exert approximately 30% of their force during this step, and the physician asks them to hold the contraction for 3 to 5 seconds.

• Step 6: The physician repositions the patient to the new restrictive barrier, as done before in Step 4, and prompts them to attempt sitting in a neutral position again, as described in Step 5.

• Step 7: Steps 4 through 6 are repeated between 3 and 5 times.

• Step 8: Finally, the physician reassesses the dysfunctional lumbar segment for improvement.

The following steps describe the treatment for a flexed, side-bent left, and rotated left diagnosis (FSlRl).

• Step 1: The patient is positioned to sit straddling a treatment table near its edge, with their back facing the physician, who may stand beside or behind them. The patient crosses their arms across their chest.

• Step 2: Positioned behind the patient, the physician places their right axilla on the patient's right shoulder. They then make contact with the patient's left shoulder using their right hand, resulting in their right arm crossing anteriorly to the patient's chest.

• Step 3: Using their left hand, the physician palpates the dysfunctional lumbar segment and maintains this position throughout the treatment to assess the restrictive barrier and monitor tissue release in the lumbar spine.

• Step 4: The physician initiates right-side bending by applying downward pressure to the patient's right shoulder through contact with the physician's axilla. Subsequently, the physician rotates the patient to the right down to the level of the lumbar spine segment by pulling the patient's left shoulder anteriorly until a restrictive barrier is palpated. The physician then leans the patient backward slightly to extend the lumbar spine until a restrictive barrier is palpated at the segment, engaging all 3 planes of motion to their restrictive barriers. This positioning places the patient's lumbar segment in a rotated right, side-bent right, and extended position opposite to the patient's lumbar spine diagnosis. Consequently, the treated segment is positioned at its restrictive barrier, allowing for correction of segmental restriction.

• Step 5: While maintaining the restrictive barrier, the physician instructs the patient to "attempt to sit in a neutral position," "turn their body to the left against the thumb placed on their back," or "push their right shoulder toward the ceiling." These instructions aim to engage specific muscle groups and apply a gentle counterforce against the physician. Essentially, the patient's side bends left, rotates left, and flexes the lumbar spine against the physician's isometric resistance created by maintaining the patient's treatment position. The patient should exert approximately 30% of their force during this step, and the physician instructs them to hold the contraction for 3 to 5 seconds.

• Step 6: The physician will reposition the patient to the new restrictive barrier, as done before in Step 4, and ask the patient to attempt to sit in a neutral position again, as described in Step 5.

• Step 7: Steps 4 through 6 are repeated between 3 and 5 times.

• Step 8: Finally, the physician reassesses the dysfunctional lumbar segment for improvement.[2]

A crucial clinical consideration during seated MET is to position the patient in a way that places the segment being treated at the apex of the side-bending/flexion/extension curve being formed. This positioning ensures that the other segments are "locked" in place, facilitating specific changes in the lesion being corrected.

Complications

The complication rate associated with MET is minimal when the appropriate type of MET is selected. Common complaints may include self-limiting soreness that resolves within a few days. Occasionally, patients may experience being "overcorrected" or "over-treated," resulting in reversing their initial lumbar diagnosis. Notably, monitoring the dysfunctional segment throughout the procedure and reevaluating it upon completion is crucial. Excessive force is a common cause of complications, as it may prevent precise treatment by engaging larger muscle groups. Reports indicate that tendon avulsion is a potential complication resulting from excessive force.[8]

Clinical Significance

Various treatments for low back pain include massage, physical therapy, exercise programs, spinal injections, transcutaneous electric nerve stimulation (TENS), patches, creams, medications, and counseling. Unfortunately, many of these treatments have inconclusive efficacy. Further research on managing low back pain is needed due to its high prevalence in patients, its large healthcare costs, and the conflicting efficacy of treatments.[4] However, some studies have shown that MET decreases back pain.[20][21][4] Misalignment of the lumbar spine or loss of lumbar joint function are common causes for non-specific low back pain, and MET works to address the root of the problem.[9] 

A pilot study performed in 2003 showed that MET significantly improved acute low back pain in which the patients underwent 4 contractions of MET held for 5 seconds each for a total of 8 treatments. They were compared to a control group that received a sham treatment. The Oswestry Disability Index (ODI) was recorded before and after MET. ODI statistically significantly improved, with a decrease in ODI by 83% in the MET group versus 65% in the control group.[22] A systematic review of 26 studies of symptomatic and asymptomatic patients found that MET effectively treats acute and chronic low back pain. This review also found that MET treats other musculoskeletal pain, such as chronic neck and epicondylitis.[5] 

Aligned with osteopathic philosophy, clinicians recognize that low back pain may not originate solely from the lumbar region. Clinicians should assess whether low back pain arises from somatic dysfunction elsewhere in the body, potentially manifesting as a compensatory reaction.[23] For example, osteopathic dysfunction in the sacrum or the innominates can cause pain in the lower back. Trigger points in the quadriceps or gluteal muscles can also cause pain in the lumbar spine.[24] Pain from the superior cluneal nerve can be confused with lumbar back pain.[25] Furthermore, it is not uncommon to consider that a patient experiencing a sprain in the lower extremity may develop compensatory changes in the knees and hips during ambulation, potentially resulting in lumbar pain due to inappropriate gait patterns.[26] Hence, low back pain may not exclusively stem from lumbar spine dysfunction. When assessing a patient with low back pain, a comprehensive approach involving a detailed trauma history and examination of the entire body is crucial.

In summary, MET represents a gentle and effective approach to managing low back pain, with a minimal risk of harm to patients during the procedure. Nonetheless, further research is warranted to delve deeper into the mechanisms of action associated with MET.

Enhancing Healthcare Team Outcomes

The interprofessional healthcare team involved in the practice of MET and osteopathic manipulative medicine includes healthcare professionals trained in these modalities, patients, and nursing staff. Physicians must ensure patients are fully informed about the treatment process during MET procedures. Physicians should be aware of the patient's experience, inquire about any worsening or new pain, and promptly terminate the procedure if the patient becomes uncomfortable. Effective communication between the physician and patient is essential throughout the treatment.