Review/Perspective: Incidence and treatment of CSF leaks/dural tears (DT) occurring during anterior cervical surgery.

Background: The incidence of cerebrospinal fluid (CSF) leaks/dural tears (DT) occurring during anterior cervical diskectomy and fusion (ACDF) are typically relatively low. However, this frequency markedly increases when anterior corpectomy and fusion (ACF) are performed to address ossification of the posterior longitudinal ligament (OPLL). Methods: The reported frequencies of CSF leaks/DT occurring during elective ACDF (i.e. exclusive of trauma), ranges from 0.24% to 1.7%. Notably, this incidence substantially rises for multilevel ACF addressing anterior OPLL, markedly varying from 3.4 - 44.7%. Results: The classical risks of anterior cervical CSF leaks/DT with anterior cervical surgery may be minimized utilizing an operating microscope. For OPLL, careful evaluation of preoperative non-contrast CT studies is critical, especially to document whether any of the 3 signs of dural penetrance is present. Here, posterior operative choices should be strongly considered in the presence of sufficient lordosis and/or a Positive K Line (+ K Line) as this will avoid an anterior cervical CSF leak/dural fistula. Alternatively, for patients with kyphosis and a Negative K Line (- K Line), preoperative anticipation and planning to treat an intraoperative anterior CSF leak/DT (i.e. direct anterior primary dural graft repair with 7-0 Gore-Tex sutures, microdural staples, microfibrillar collagen, wound-peritoneal shunt, and lumbar drain or lumboperitneal shunt) are essential in the course of performing direct anterior OPLL resection. Conclusion: The incidence of anterior cervical CSF leaks/DT is relatively low (i.e. range 0.24 - 1.7%) where ACDF is performed for disc disease/spur/spondylosis exclusive of OPLL. However, where ACF is performed for multilevel OPLL, the risk of CSF Leaks/DT is substantially higher (i.e. range 4.3-44.7%).