Intraoperative Measurements of Nerve Root Tension During Posterior Lumbar Interbody Fusion

Abstract Background There is no effective standard method to evaluate whether the nerve root tension is restored, which is an important indicator for the recovery of nerve function. This study aimed to demonstrate a technique for measuring nerve root tension during surgery. Methods A total of 54 consecutive patients (average age, 52.3 years; range, 28-68 years) received posterior lumbar interbody fusion for lumbar disc herniation comprised the patient sample.The nerve root tension was measured twice before and after intraoperative decompression by the nerve root tension meter modified from the transverse gauge by author. Clinical outcome was assessed by the visual analog scale (VAS) for leg pain, provided by patients before and after surgery. Results There was a significant improvement in the VAS score for leg pain after surgery compared with that before surgery (7.0 ± 2.24 vs. 0.8 ± 0.84, respectively; P < 0.01). Nerve root tension was significantly decreased after decompression compared with that before surgery (1.32 ± 0.22 N vs. 0.64 ± 0.17 N, respectively; P < 0.01). The nerve root tension was positively correlated with the VAS score (r = 0.772, P < 0.05; r = 0.715, P < 0.05). Conclusions This study shows that the nerve root tension meter can instantly and non-invasively measure nerve root tension during an operation. It was demonstrated that the nerve root tension of the patient is significantly reduced after decompression. Meanwhile, the VAS score improved significantly, and the nerve root tension and VAS scores were positively correlated.