Unexpected postoperative cerebrospinal fluid leaks without intraoperative dural tears after posterior lumbar interbody fusion

Objectives Postoperative cerebrospinal fluid (CSF) leaks ussually occur after intraoperative dural tears. Sometimes, however, CSF leaks are found postoperatively even in the absence of intraoperative dural tears. The frequency and course of postoperative CSF leaks without intraoperative dural tears after posterior lumbar interbody fusion (PLIF) were investigated. Material and Methods The subjects were 200 patients (112 males, 88 females, age 69 ± 10 years) who underwent PLIF at our hospital from July 2014 to March 2020. The causative diseases were lumbar spinal stenosis in 167 cases, spondylolisthesis in 11 cases, lumbar disc herniation in 16 cases, and degenerative scoliosis in six cases. Of all the 200 cases, 27 were revision cases. If a dural tear occurred during the operation, dural repair was performed intraoperatively. Drain suction with negative pressure was discontinued when postoperative CSF leaks were found. Results Of the 180 patients without intraoperative dural tears, postoperative CSF leaks were observed in 27 patients (15.0%). Of these 27 patients, three symptomatic patients required reoperation. Residual CSF accumulations one year after surgery were observed in 14 patients, of whom six patients had severe CSF accumulations with a dural sac deformity, all of whom were asymptomatic. Of the 20 patients with intraoperative dural tears, 16 patients (80.0%) had postoperative CSF leaks, but none needed reoperation. Conclusion The frequency of postoperative CSF leaks without intraoperative dural tears was 15.0% in the present study. They require strict follow-up because they can cause severe postoperative CSF accumulations and may require reoperation.