Spinal Manipulation

Original Editor - Stacey Jones and Ashley Gunzenhauser.

Lead Editors - Christian Stamou, Alistair Husband and Robert Dent

Description

By The U.S. Army (www.Army.mil) [Public domain], via Wikimedia Commons

Manipulation is a passive technique where the therapist applies a specifically directed manual impulse, or thrust, to a joint, at or near the end of the passive (or physiological) range of motion. This is often accompanied by an audible ‘crack’.  The common feature of spinal manipulation techniques is the fact that they achieve a pop or cracking sound within synovial joints. The cause of this audible release is open to some speculation but it is widely accepted to represent cavitation of a spinal facet joint. When there is a lower pressure than normal in the facet joint, gas bubbles are being formed in the joint. At the moment that the pressure rises, the bubble implodes, this is called cavitation.

It is a intervention Physiotherapists have been employing since the beginning of physical therapy practice. However, physiotherapists providing spinal manipulations have come under the scrutiny of other professions even though manipulation is not exclusive to any one domain or profession. The challenge has been brought forth to many state legislators because some chiropractors have argued that manipulations are not within the scope of physiotherapy practice. The APTA has created a page that delineates the difference between physical therapy manipulation and chiropractic manipulation. They have also published a manipulation education manual.

Effects of Manipulations

Spinal manipulations can relieve back pain by taking pressure off sensitive nerves or tissue, increase range of motion, restoring blood flow, reducing muscle tension, and, like more active exercise, promote the release of endorphins within the body to act as natural painkillers.

Recent research has shown that the neurophysiological effects of a single session of spinal mobilization are mostly 5 minutes or less. An exception to these findings is hypoalgesia which may last up to 24 hours.

It has been suggested that manipulations are more effective for pain induced by pressure than temperature with pain by pressure being assessed by pressure pain threshold (PPT) - defined as the minimal pressure that elicits pain or discomfort (Honore et al., 2018).

Cervical Spine

The cervical region accounts for the vertebrae of C1-C7, and is the most upper region of the spine (the neck). The NICE guidelines for non-specific neck pain make references to 2 types of manipulations that can be used. Firstly, the APTA actually recommend the use of Thoracic manipulations for neck pain first, however the guidelines also state that cervical manipulations can also be used on a patient with recent onset of neck pain. NICE guidelines state that Grade 5 manipulations for neck pain can be used either alone or in combination with other treatment methods such as strengthening and ROM exercises . With guidelines stating that spinal manipulation for neck pain can be used by a qualified physiotherapist, it is important to look at the evidence around the effectiveness of cervical manipulations.

A systematic review including 27 RCTs (1522 participants) through Cochrane databases looked to assess if manipulation or mobilisation improves pain, function/disability, patient satisfaction, quality of life, and global perceived effect in adults with acute,sub-acute and chronic neck pain with or without cervicogenic headache or radicular findings. The review's key findings concluded that for Cervical manipulations alone:

• There is moderate quality evidence (two trials, 369 participants) that manipulation produces similar changes in pain, function and patient satisfaction when compared to mobilisation for subacute or chronic neck pain at short- and intermediate-term follow-up.
• There is low quality evidence (three trials, 130 participants) that manipulation alone versus a control may provide immediate- and short-term pain relief following one to four treatment sessions in subjects with acute or chronic neck pain
• Cervical manipulations are equivalent to certain medication (2 trials, 69 participants), acupuncture (2 trials, 81 participants), certain soft-tissue treatments (1 trial, 53 participants)
• Evidence suggests manipulations are superior than TENS for individuals with chronic cervicogenic headaches.

Another systematic review was conducted on the effects of manipulations on neck disorders in order to create evidence based clinical guidelines for their use. Based on the paper's findings:

• There was indication that when manipulations are used in conjunction with other treatments (exercise, thermal modalities, patient education and rare use of a collar), the results favour this intervention.
• There was inconclusive evidence to support the use of manipulation alone

The take away message is that cervical manipulations may be an effective short-term pain relief for patients with mechanical neck disorders, when used in conjunction with other treatment techniques. All research papers mentioned in this section support the NICE guidelines advice on manipulation use for the cervical region.

Thoracic Spine

The thoracic region encompases the verterbrae T1-T12, and is located in the middle region or thorax of the body. Unlike other areas of the spine, each of the vertebrae present has a rib attached to it, resulting in the the thoracic cage being attached to the Thoracic region of the spine. There is minimal evidence surrounding the use of thoracic manipulations for the relief of thoracic pain, but there is evidence for use in relief of neck pain and increasing respiratory function.

Neck Pain

As covered earlier, the NICE guidelines recommend the use of thoracic spinal manipulation in conjunction with range of movement and strengthening exercises to help relieve neck pain. Their recommendation is based on the American Physical Therapy Association guidelines. The APTA guidelines state that "For patients with acute neck pain with mobility deficits, there was a benefit compared to control for using multiple sessions of thoracic manipulation for reducing pain over the immediate and short term". They go on to further describe how the thoracic spinal manipulation provided a small improvement on pain, quality of life and function over an intermediate duration of time. Despite the recommendations by NICE and APTA, it is important to understand the limitations of thoracic spinal mobilisation, and how you can incorporate this technique into your management of patients neck pain.

One of the systematic reviews performed the current NICE and APTA guidelines, investigated how effective Thoracic Spine Manipulation was at reducing pain and disability in patients diagnosed with non-specific neck pain. It included 10 RCTS with 677 patients, and found a high variance within the methodological quality of the RCTS included. Overall the review found insufficient evidence that Thoracic Spine Manipulation is more effective than control treatments. However it found that Thoracic Spine Manipulation has therapeutic benefit to some patients with neck pain, therefore should be considered for use in combination with other treatments for non-specific neck pain.

A systematic review performed in 2019 , looked at management of pain and disability from mechanical neck pain with the use of thoracic manipulations. It included 14 appropriate randomised control trials with a total of 885 participants, these participants were randomly assigned to either a thoracic manipulation group or a control (except for two RTCs, where they were used a comparison group using another method of neck pain management).

Overall the review concluded that thoracic spinal manipulation improves short term pain and disability and self assessed functionality when compared to thoracic mobilization, cervical mobilization and standard care. But not when compared to cervical manipulation or placebo thoracic manipulation. This review also concluded that the current overall quality of evidence ranged from very low to moderate when assessed using the GRADE approach.

Indication for LBP

The underlying pathological cause of low back pain (LBP) is only determined in about 15% of all cases. Because of this, there has been much confusion and debate about the best way to treat patients with LBP. There have been numerous studies done to determine the effectiveness of different treatment interventions for these patients. Evidence has been conflicting regarding the effectiveness of spinal manipulation as an intervention in this patient population. Spinal manipulative therapy is less effective than often assumed. The enthusiasm for this treatment as thé treatment for low back pain should be tempered. There is no evidence found that spinal manipulation is superior to other therapies such as back schools, physical therapy and exercises. But it is also not proven that these therapies are superior to spinal manipulation. So spinal manipulation is one of the several options for the treatment of patients with low back pain. The remark that all these findings are of modest effectiveness should be kept in mind.  Next to it, manipulations are found more effective in the acute than in the chronic cases of low back pain. It has to be noticed that manual therapy is only indicated in the acute cases which have a varied course.  On the other hand, it is proven that spinal manipulative therapy appears to be no better or worse than other existing therapies for patients with chronic low-back pain.

The best way of using the manipulations is in combination with other therapeutic modalities. There is evidence from a high quality study, that spinal manipulative therapy combined with exercise is more effective than other procedures like spinal manipulation, exercise or physician consultation alone.

Flynn et. al determined that patients that meet certain criteria were more likely to experience short-term improvements with spinal manipulation. A clinical prediction rule was developed in order to identify these patients with LBP who will most likely benefit from spinal manipulation. Spinal manipulation is a sub-group of the Treatment-Based Classification Approach for low back pain.

The use of spinal manipulation as part of treatment for low back pain is recommended by several clinical practice guidelines, including the New Zealand Guidelines for Acute Low Back Pain, and the recently published NICE guidelines.

Clinical Prediction Rule for Manipulation

The following five factors are the criteria included in the five factor predictor rule for manipulation  :

• Pain lasting less than 16 days

• No symptoms distal to the knee

• FABQ score less than 19

• Internal Rotation of greater than 35 degrees for at least one hip

• Hypomobility of a least one level of the lumbar spine

The patients that received the most benefit from spinal manipulation for LBP are those that met at least four out of the five criteria for spinal manipulation.The positive likelihood ratio for those exhibiting four out of five of the factors is 24.3 
However, the two most important identifiers for manipulation are: 

• Pain lasting less than 16 days

• No symptoms distal to the knee 

The following six factors are the criteria for immediate responders to cervical manipulation:

• Initial scores on Neck Disability Index <11.50
• Having bilateral involvement pattern
• Not performing sedentary work >5 h/day
• Feeling better while moving the neck
• Without feeling worse while extending the neck
• Diagnosis of Spondylosis without Radiculopathy

The presence of four or more of these predictors increased the probability of success with manipulation to 89%.

Lumbar Spine

A spinal manipulation to the lumbar spine is a common intervention administered for patients with Low Back Pain (LBP). According to Honore et al. (2018), 63% of 984 LBP patients reported immediate pain improvements following spinal manipulation. It has also been suggested that manipulations have demonstrated better outcomes compared to exercise, education, and other treatment interventions when investigating when assessing experimentally induced pain .

The findings from the systematic review by Honore et al. (2018) identified that spinal manipulations in the lumbar region have significant effect on pain perception thresholds in asymptomatic participants, but there appears to be no significant difference between spinal manipulations and other treatment modalities (e.g. mobilisations, physical therapy or manipulation in another spinal region). They also identified that when a manipulation was compared to a sham intervention that was credible, the results were more likely to be significant than when the sham intervention lacked credibility - therefore arguing against the placebo effect. As a result, this suggests Spinal manipulations are effective in improving PPT within asymptomatic participants

The Lumbar spine is a common region that therapists use spinal manipulative therapy. A research study by Dorren et al. (2016) investigated whether a spinal manipulation to the lumbar region altered pressure pain threshold (PPT) and pinprick sensitivity (PPS). Their study involved asymptomatic participants (N=34) between the ages of 18-45 (average age = 24). A strict exclusion criteria was used to reduce the chance of bias influencing the results. The spinal manipulation was administered at L5/S1 region using the common hypothenar mammillary push. Significant effects were observed for PPS at the calf (P<0.05) and the lumbar spine (P<0.05) with weak effect sizes. However, significant increases in PPT were observed between baseline to 20 and 30 minutes at the calf, and 10, 20 and 30 minutes at the lumbar spine. Significant effects were also witnessed for PPS at the calf, lumbar spine and forehead. The results suggested significant decreases in PPS at the calf between baseline, 20 and 30 minutes whereas decreases were seen immediately, 10, 20 and 30 minutes for the lumbar spine. To conclude, this study observed significant increases in PPT at the lumbar spine and calf following a Lumbar Spine manipulation with effects lasting up to 30 minutes. Furthermore, PPS also decreased at each location with both outcome measures affecting A beta fibres. Therefore, it's possible to suggest Lumbar manipulations can reduce deep pressure sensitivity locally and in the lower limbs .

Some research has also been carried out to investigate the effects of spinal manipulations on increasing muscular strength in healthy individuals. Ngai et al. (2019) suggest that manipulations can improve motor responses by restoring physiological dynamics of adjacent vertebrae which consequently improves the function of the nervous system and promotes central facilitation . The authors believe that manipulations would reduce trapped meniscoids, adhesion or distortions within the annulus fibrosus. After a strict exclusion criteria, only 3 studies remained which were all Randomised Control trials totalling 102 asymptomatic participants. When lumbar spinal manipulations were compared to low grade mobilisations (1-4 on the Maitland scale), and sham lumbosacral and thoracic manipulations. The authors found that manipulations are superior to no intervention and the sham treatments with a large effect size of 0.93 and increased isometric muscle strength in the neck, back and peripheral muscles .

Contra-indications

The following scenarios are contraindications to low back pain  :

• Any pathology that leads to significant bone weakening
• Neurological: cord compression, cauda equina compression, nerve root compression with increasing neurological deficit
• Vascular: aortic aneurism, bleeding into joints
• Lack of diagnosis 
• Patient positioning can not be achieved because of pain or resistance.

Adverse Effects

• Vertebral artery dissection
• Acute vertigo
• Cerebro vascular accidents

As you can notice, almost all complications are found with patients whom has been treated for a neck problem and not a thoracale or lumbar problem. A big question that remains unsolved is the incidence of the adverse effects. The evidence behind the incidence of adverse effects is unknown. One paper based on weak evidence estimates serious complications being between 1 in 20,000 to 5 in 10,000,000.

Key Evidence

Fritz, Cleland, and Childs published an article in 2007 entitled "Subgrouping Patients With Low Back Pain: Evolution of a Classification Approach to Physical Therapy" which lays out the Treatment Based Classification Approach and explains the classification critia for the different intervention subgroups.

Spinal Manipulative Therapy for Low Back Pain (Cochrane Review)

Spinal Manipulative Therapy for Chronic Low Back Pain (Cochrane Review)

Resources

 Manipulation/Mobilisation - Facts about physiotherapy and spinal manipulation from the APTA