Change of the Intervertebral Foraminal Pressure after Removal of the Disc Material.

Hong, Chang Kie; Park, Chong Oon; Hyun, Dong Keun; Ha, Young Soo

Original Article

Journal of Korean Neurosurgical Society 2001;30(2): 144-149.

Chang Kie Hong, Chong Oon Park, Dong Keun Hyun, Young Soo Ha

Department of Neurosurgery, College of Medicine, Inha University, Seongnam, Korea.

ABSTRACT

OBJECTIVE
S: Spinal nerve root compression occurs commonly in conditions, such as herniated nucleus pulposus, spinal stenosis, intervertebral foraminal stenosis, and trauma. However, the pathophysiolosy of the symptoms and signs related to spinal nerve root compression is poorly understood. The purpose of the present study was to assess and compare the changes of various pressures of intervertebral foraminal pressure before and after decompression.
METHOD
After laminetomy without foraminotomy was performed, pressure sensor tip of Camino parenchymal type was located at the middle-central portion of the intervertebral foramen and anterior portion of nerve root for the foraminal pressure before decompression of the intervertebral foramen. After laminectomy with foraminotomy, the same method was used for the foraminal pressure after decompression. The authors studied 40 consecutive patients (57 disc spaces) with severe constant root pain to the lower leg, pain unrelived by bed rest, and minimal tension signs, diagnosed by MRI.
RESULTS
In patients with intervertebral foraminal stenosis, the intraforaminal pressure was decreased from 86+/-2.23mmHg to 17.1+/-1.51mmHg and in patients without stenosis, from 55.9+/-1.08mmHg to 11.9+/-1.25mmHg. All patients below 20mmHg after decompression showed good outcome, but 4 cases who showed poor outcome had foraminal stenosis, posterolateral type of the herniated disc, and above 30mmHg of foraminal pressure after decompression.
CONCLUSION
These findings suggest that if the foraminal pressure falls below 20mmHg after decompression, good outcome can be anticipated. Central type of the herniated disc shows better outcome compared to the posterolateral type.

Key Words: Intervertebral foraminal stenosis; Intraforaminal pressure; Spinal nerve root compression