What keeps the spine healthy and erect?

Washington, Jan 12 : What keeps the spine healthy and erect? The key lies in how a deep muscle along the spinal column, called the multifidus muscle, is designed.

These findings show how this poorly understood muscle plays a potentially important "scaffolding" role, according to researchers from University of California San Diego School of Medicine (UCSDSM).

"The multifidus muscle was formerly thought to be relatively unimportant based on its fairly small size," said Richard L. Lieber, professor at UCSD department of orthopaedic surgery.

"Our research shows that it's actually the strongest muscle in the back because of its unique design. It's like a long, skinny pencil packed with millions of tiny fibres," he added.

Researchers discovered that the multifidus has a unique packing design consisting of short fibres arranged within rods, and that these fibres are stiffer than any other in the body.

Using laser diffraction methods that they developed to measure muscle internal properties during back surgery, they demonstrated that the multifidus' unique design serves a critical function as a stabilizer of the lumbar spine.

These findings could have implications for surgery, according to Steven R. Garfin, professor and ortho surgeon at UCSDSM, said its release.

These findings were published online in advance of the January issue of the Journal of Bone and Joint Surgery.

Garfin explained that currently surgery to treat spinal disorders could actually disrupt the multifidus muscle, which could lead to decreased stabilisation and lower back pain. Minimally invasive spine surgery techniques strive to minimise surgical trauma to these muscles in order to best preserve their function.

The lower back, or lumbar spine, can be vulnerable to many pain-causing injuries or disorders because the lumbar vertebrae carry the most body weight and are subject to the most force and stress along the spine. Muscular instability is a risk factor in many injuries and consequent chronic lower back pain, according to Lieber.