Failed back surgery linked to dysfunctional diaphragm

Failed back surgery syndrome: review and new hypotheses – J Pain Res. Jan 2016 – free full-text PMC article

This article posits that failed back surgery may be linked to a dysfunctional diaphragm because “diaphragm dysfunction would lead to alterations in the biomechanics of the lumbar spine”.

Failed back surgery syndrome (FBSS) is a term used to define an unsatisfactory outcome of a patient who underwent spinal surgery, irrespective of type or intervention area, with persistent pain in the lumbosacral region with or without it radiating to the leg.

This article reviews the current literature on FBSS and tries to give a new hypothesis to understand the reasons for this clinical problem.

The possible reasons and risk factors that would lead to FBSS can be found in distinct phases:

  • in problems already present in the patient before a surgical approach, such as spinal instability,
  • during surgery (for example, from a mistake by the surgeon), or
  • in the postintervention phase in relation to infections or biomechanical alterations.

The dysfunction of the diaphragm muscle is a component that is not taken into account when trying to understand the reasons for this syndrome, as there is no existing literature on the subject.

The diaphragm is involved in chronic lower back and sacroiliac pain and plays an important role in the management of pain perception.

Introduction

Pain may appear after surgery and persist despite the intervention for up to 3 months, with chronic consequences.

There are other definitions for the same disorder such as

  • postlumbar surgery syndrome,
  • postlaminectomy syndrome,
  • failed back syndrome, [No, it’s the surgery that failed,not the back or the patient]
  • postoperative persistent syndrome

In the text studied,

  • the percentage of pain detected after spinal surgery varies ranging from a low of 5% to a high of 74.6%, and
  • the percentage of need for re-operation ranging from 13.4% to 35%.

At present there are no surgical strategies able to prevent the instances of FBSS.

The diaphragm in the context of FBSS

One component that is not even considered when trying to understand the reasons for FBSS is dysfunction of the diaphragm muscle, which is not referred to in the literature.

The diaphragm is involved in chronic lower back and sacroiliac pain and plays an important role in the management of pain perception.

The respiratory diaphragm muscle is innervated by the phrenic nerve (C3–C5) and the vagus nerve (cranial nerve X); the first receives pulses from groups of medullary neurons of the Pre-Bötzinger complex and neurons of the parafacial retrotrapezoid complex, which in turn receive orders over retroambiguus from the core of the bulb, although the mechanisms that underlie these links are not completely clear.

Dysfunction of the diaphragm

Dysfunction of the diaphragm is an important factor and recognized as being one of the causes of low back and sacroiliac joint pain. People who suffer from low back and sacroiliac joint pain often have early fatigue of the diaphragm muscle, altered and diminished respiratory excursion as well as inadequate proprioceptive function.

The diaphragm dynamically stabilizes the lumbar spine.

It lowers on inhalation, stabilizing the abdominal pressure, together with the lower ribs, which have moved downwards, with a larger movement for its ventral size compared to the dorsal area.

There is a close relationship between a reduction in the movement of the diaphragm and the intensity of pain in people who suffer from low back pain.

When the lower limbs are called upon to work, the diaphragm is activated to stabilize the spine and allow the movement required; in people with chronic pain this happens to a lesser extent. The ribs do not drop and do not allow the diaphragm to have a fixed point to lower to; there is a minor reduction in the diaphragm dome with reduced ability to manage the intra-abdominal pressure, ultimately causing lumbosacral instability

This biomechanical alteration is also found in trauma to the spinal column, for example, resulting from an accidental fall that alters the lumbar movement changing the pattern of diaphragm activation.

When the diaphragm is not working correctly, its proprioceptive ability is reduced, further slowing down its stabilizing function on the lumbar region.

This is true even if other muscles that contribute to the stabilization of the back do not work properly (as the paraspinal muscles, the abdominal muscles and the transversus abdominis, the quadratus lumborum and the gluteus medius), which may interfere negatively on the proprioceptive function of the diaphragm

Another report to be considered in further understanding the complex functions of the diaphragm muscle as a stabilizer of the lower back is the thoracolumbar fascia (TLF).

The whole spinal column is held together and aligned by bands of fascia, so this becomes a problem for people with the defective connective tissue, like with EDS.

The TLF is defined by Willard et al as:

… a complex myofascial and aponeurotic girdle surrounding the torso. On the posterior body wall, the central point of this girdling structure is the thoracolumbar fascia (TLF), a blending of aponeurotic and fascial planes that forms the retinaculum around the Paraspinal muscles of the lower back and sacral region. 

The lateral and medial pillars of the diaphragm are in close connection with the lumbar vertebrae and the lower ribs, and in such a way that the arched pillars of the diaphragm act as a bridge between the TLF posteriorly and the transversalis fascia anteriorly.

The TLF system allows for the tensions generated by movement and breathing along the spine of the back to be conveyed correctly, creating synergy with the lowering of the diaphragm, a sort of “sleeve” that surrounds the lumbar vertebrae, allowing for stabilisation.

The thoracolumbar spinal fascial tissue damaged by surgery will not have the same elastic and proprioceptive capacity, compared to an intact tissue, which causes mechanical malfunctions; a TLF in difficulty leads to instability of the spine.

This is a typical problem with EDS: weak or defective fascia can cause mechanical malfunctions in any and all parts of the spine.

Probably, the functional loss of this fascial system may disturb the work of the diaphragm, causing a cascade of pathological events such as pain and biomechanical alterations in the lumbosacral region.

This is exactly how defective fascia in one area can lead to a “cascade” of consequences in other areas, passed along a chain of bodily systems that depend on each other.

It can be strongly hypothesized that a dysfunction of the diaphragm muscle as a stabilizer to the lumbosacral column is one of the causes leading to FBSS that is caused by factors preceding surgery or following spinal surgery. A function of the diaphragm that could be disturbed in FBSS is its analgesic action, this dysfunction can become one of the causes of chronic pain.

Pain, emotions, and the breath

There is a close relationship between emotions, breathing, and the intervention of baroreceptors.

See also PubMed article, Sympathetic Dysfunction in Patients With Chronic Low Back Pain and Failed Back Surgery Syndrome.

It can be said that the diaphragm has an influence on baroreceptors and the perception of pain and vice versa.

The diaphragm and its movements change the body pressure, in that the diaphragm facilitates the venous and lymphatic return upwards This modulation in pressure influences the re-distribution of blood It is very likely that this determines the baroreceptor, response and a reduction in pain perception; however, there are still no scientific texts to support this assertion

An incorrect diaphragm position as in chronic low back pathologies could lead to inadequate stimulation of baroreceptors and incorrect function of the same; this could lead to a heightened sensibility to a greater feeling of pain.

The same diaphragm can be a source of pain afferents probably due to the phrenic nerve, a mixed nerve that carries motor and sensory information, sharing information with the spinal trigeminal nucleus.

The diaphragm has a phrenic center, consisting of a strong “V” shaped connective component with a variable percentage in respect to the amount of contractile tissue

The fascial system is richly innervated by proprioceptors, which can become a source of painful afferents that can transform into nociceptors.

Conclusion

A component that is not even considered when trying to understand the causes that lead to FBSS is the dysfunction of the diaphragm muscle, such that texts in literature do not mention the subject.

The diaphragm is involved in chronic lower back and sacroiliac pain and plays an important part in the management of pain perception. Its dysfunction due to positional alterations could be one of the major underlying causes of chronic pain in this patient population.

This is because the diaphragm dysfunction would lead to alterations in the biomechanics of the lumbar spine,

  • with less proprioceptive abilities,
  • less movement of the vertebrae, and
  • reduction of functional collaboration

of tissues that are involved in the proper functioning of the lumbar area; or less stabilization, or it provides less stimulation of baroreceptors by the diaphragm and an alteration in the perception of pain.

In conclusion, the diaphragm itself could be a source of pain, due to the change of its proprioceptors or irritation of the phrenic nerve and the vagus nerve.

If scientific research were to prove that the diaphragm muscle plays an important role in FBSS, the therapeutic approach might provide an additional step toward improving the clinical condition and quality of life in this patient population.

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