Intradiskal pressure and volume recording: evaluation of normal and abnormal cervical disks.

Rupture of the normal intervertebral disk by manual force is difficult. When the pressure was raised to 9000 mm Hg. in 33 normal intervertebral disks, the volume received did not exceed 0.4 cc. A contained degenerated intervertebral disk can be ruptured by manual force without a simultaneous pressure-controlling device. In cases of traumatic rupture of the annulus fibrosis and of the posterior longitudinal ligament, simultaneous intradiskal pressure and volume recording were more informative than either EMG or myelography. Simultaneous intradiskal pressure or volume recording is capable of detecting a normal intervetebral disk and thus may be diagnostically helpful by the process of elimination. The diskometry or volume study, with or without simultaneous intradiskal pressure recording, has very limited diagnostic value in the detection of a symptom-producing intervertebral disk. Differentiation between degenerated asymptomatic and herniated symptomatic disks could not be made with pressure volume recording.