As people who needle, we often emphasize needling the paraspinal muscles associated with the segemental innervation of the peripheral muscle you are needling. For example, you may needle the L2-L4 paraspinals (ie: femoral nerve distribution) along with the quads, or perhaps the C2 PPD’s along with the suboccipitals. We do this to get more temporal and spacial summation at a spinal cord level, to hopefully get better clinical results, like we talked about in this post here.

White and Panjabi described clinical instability as the loss of the ability of the spine, under physiologic loads, to maintain relationships between vertebrae in such a way that there is neither damage nor subsequent irritation to the spinal cord or nerve roots, and, in addition there is no development of incapacitating deformity or pain due to structural changes (1)

Increased movement between vertebrae (antero or retrolisthesis) of > 3.5 mm (or 25% of the saggital body diameter) during flexion and/or extension suggests clinical instability (1). This often leads to intersegmental dysfunction and subsequent neurological sequelae which could be explained through the following mechanisms:

Recall that the spinal nerve, formed from the union of the ventral (motor) and dorsal (sensory) rami, when exiting the IVF splits into an anterior and posterior division, supplying the structures anterior and posterior to the IVF respectively. The posterior division has 3 branches: a lateral branch that supplies the axial muscles such as the iliocostalis and quadratus; an intermediate branch, which innervates the medial muscles, such as the longissimus, spinalis and semispinalis; and a medial branch, which innervates the segmental muscles, (multifidus and rotatores) as well as the joint capsule. Inappropriate intersegmental motion has 2 probable neurological sequelae: I) alteration of afferentation from that level having segmental (reflexogenic muscle spasm or vasoconstrictive/vasodilatory changes from excitation of primary afferents and gamma motoneurons) and suprasegmental (less cerebellar afferentation, less cortical stimulation) effects and II) compression or traction of the medial branch of the PPD (2), causing,  over time, demyelination and resultant denervation, of the intrinsic muscles, resulting in impaired motor control both segmentally and suprasegmentally. The segmental effects are directly measurable with needle EMG. This is a form of paraspinal mapping, which has also been explored by Haig et al (3). So, in short, instability can lead to denervation and denervation can lead to instability.

 We often see clinically that needling a trigger point alters the function of the associated muscle (4-7). Improvements in muscle strength and changes in proprioception are not uncommon. Needling also seems to increase fibroblastic activty through the local inflammation it causes. Wouldn’t better muscle function and some scar tissue be a beneficial thing to someone with instability?

The next time you have a patient with instability, make sure to include the paraspinals in your quest for better outcomes.

References:

1. White A, Panjabi M in Clinical Biomechanics of the Spine, JB Lippincott, Philadelphia, PA 1978, p192

2. Sihvonen T, Partanen J. Segmental hypermobility in lumbar spine and entrapment of dorsal rami. Electromyogr Clin Neurophysiol. 1990 Apr-May;30(3):175-80.

3. Haig AJ, Talley C, Grobler LJ, LeBreck DB. Paraspinal mapping: quantified needle electromyography in lumbar radiculopathy. Muscle Nerve. 1993  May;16(5):477-84.

4.  Dommerholt j: Dry needling — peripheral and central considerations Journal of Manual and Manipulative Therapy 2011 VOL. 19 NO. 4 223-237

5. Pavkovich R : EFFECTIVENESS OF DRY NEEDLING, STRETCHING, AND STRENGTHENING TO REDUCE PAIN AND IMPROVE FUNCTION IN SUBJECTS WITH CHRONIC LATERAL HIP AND THIGH PAIN: A RETROSPECTIVE CASE SERIES The International Journal of Sports Physical Therapy | Volume 10, Number 4 | August 2015 |

6. Qian-Qian Li, Guang-Xia Shi, Qian Xu, JingWang, Cun-Zhi Liu, and Lin-Peng Wang Acupuncture Effect and Central Autonomic Regulation Evidence-Based Complementary and Alternative Medicine Volume 2013, Article ID 267959, 6 pages

7. Skorupska et al. BMC Complementary and Alternative Medicine (2015) 15:72 DOI 10.1186/s12906-015-0587-6