Nucleotomy Alters Mechanical Function Following Cyclic Loading and Unloaded Recovery of Human Discs

The intervertebral disc plays a critical role in supporting loads, permitting spinal motion, and dissipating energy. Unfortunately, it is also commonly degenerated, resulting in altered spinal mechanics and low back pain. Nucleotomy is a common treatment for herniated discs and is also used experimentally to simulate degeneration.[1] The procedure, which involves a posterior annular incision and removal of a portion of the nucleus pulposus (NP), has also been shown to alter disc mechanics. These changes include acute changes of decreased NP pressure, decreased disc height, and increased neutral zones.[2, 3] Cyclic studies have shown that trans-endplate nucleotomy permanently alters creep mechanical properties of sheep discs.[4] However, the effects of annular nucleotomy on the cyclic properties of human discs have not yet been studied. This work studied the mechanical effect of annular nucleotomy on human discs subjected to physiological axial cyclic loading.