Measurement of intradiscal pressure after lumbar discectomy.

OBJECT: Early physiotherapeutic exercises after lumbar discectomy have been shown to be helpful for pain control and in reducing the delay until the return to work. Many strategies exclude sitting body positions during the first weeks, because raised intradiscal pressure and an increased motion range in the lower lumbar disc levels have been found in unoperated individuals when seated. To evaluate whether these results can be extrapolated to the situation of an operated patient, we examined the feasibility of an intracranial pressure sensor for measuring intradiscal pressure after lumbar discectomy. PATIENT AND METHOD: An otherwise healthy patient underwent lumbar discectomy for a right-sided lumbar disc herniation at the level L4/5. Before surgery he had agreed voluntarily to the implantation of a pressure sensor and the manufacturer had provided data on the safe use of the sensor in the disc space. Intraoperatively the sensor was positioned in the disc space from the right side. Measurements were performed by means of individual readings by three different examiners at different time points. Before removal of the sensor its correct position was demonstrated by X-ray and computed tomography. RESULTS: The patient tolerated surgery very well, recovery and wound healing were un-eventful, and symptoms improved. The pressure monitoring system showed reproducible results without any signs of technical problems. The intradiscal pressure values were about ten times lower than the values known from unoperated individuals (lying: up to 130 mmHg, sitting: up to 50 mmHg, standing: up to 450 mmHg. 100 mmHg=0.013332 MPa). CONCLUSION: We present an easy to perform and technically safe technique for the measurement of intradiscal pressure after lumbar discectomy using an intracranial sensor. To assess the impact of intradiscal pressure on recovery after lumbar microdiscectomy a study with a larger cohort of patients and with long-term follow-up will be needed.