By Dr. Mahdi Shkoukani, Cleveland Clinic Abu Dhabi, UAE

As anterior skull base surgery evolved in the last 20 years from open approaches to expanded endonasal endoscopic approaches, the role of lumbar drain in perioperative period continues to be a debatable topic. It was postulated in the open approach era that lumbar drain may decrease Cerebro-Spinal-Fluid (CSF) leak postoperatively and help decompress dura after tumour resection. Most importantly, it has been believed that lumbar drain will help prevent tension pneumocephauls, which may develop in 1-7 per cent of skull base cases. Literature shows contradicting evidence regarding the role of lumbar drain in skull base surgery to the point that some research linked lumbar drain to development of tension pneumocephalus rather than treating it. Due to this confusion in literature, surgeons had relied heavily on low level evidence literature or their own experience of whether to favour lumbar drain or not.

Advancement in endoscopic skull base surgery have led into a shift toward a minimally invasive approach; improvement in reconstructive techniques, decreased length of stay and a better cosmetic outcome. Nevertheless, CSF leak continues to be a major complication ranging between 3-21 per cent.

Lumbar drain is not a complication-free procedure. Minor and major complications have been documented in 3-5 per cent of cases. Minor complications include headache, nausea, nerve root irritation and local infection. Major complications include meningitis, retained catheter, subdural/subarachnoid hematoma and subdural/subarachnoid abscess. In addition, patients with lumbar drain in place are usually on bed-rest, which may increase their risk for development of Deep Venous Thrombosis (DVT) and other comorbidities related to their immobility status.

There are multiple potential aetiologies for CSF leak. Such aetiologies include traumatic, spontaneous and iatrogenic causes. In regard to traumatic leak, there is an agreement by most surgeons and centres to treat this conservatively initially. Surgical repair and/or lumbar drain may be considered for persistent leaks. Controversy in considering lumbar drain in CSF leak treatment remains prevalent in the iatrogenic and to less extent the spontaneous leak group. These two latter groups need surgical repair, but the question is whether a lumbar drain is needed. It is believed that many of the spontaneous leaks are potentially related to undiagnosed intracranial hypertension. Many recent studies have shown that a good surgical repair with management of intracranial hypertension is all what is needed. Some surgeons continue to use lumbar drain routinely, mainly due to the fact that they were trained that way and feel more comfortable. The iatrogenic group is a diverse one. This group includes CSF leak that results from open or endoscopic skull base surgery during tumour resection or as a complication of functional endoscopic sinus surgeries. There is some disagreement in literature regarding using lumbar drains in this group compared to the two former groups.

One explanation to the various recommendations in regard to lumbar drain’s role in skull base is due to the quality of the literature published. Majority of publications are at best level III. Also, there have been different selection criteria where many studies included slow and high leaks without any differentiation, which led to dilution of potential effect. The only randomised controlled trial that looked at lumbar drain’s role in skull base surgery was recently published in 2018 at the Journal of Neurosurgery by Dr. Swagerman and his colleagues at the University of Pittsburgh. One hundred seventy patients were randomised equally to two arms: with lumbar drain and without lumbar drain. Inclusion criteria was one of its strengths. They included only high flow leak, which are by definitions dural defects greater than 1 cm2, extensive arachnoid dissection, and/or dissection into a ventricle or cistern. This study showed a class I evidence that lumbar drain was statistically beneficial in decreasing postop CSF leak.

Secondary analysis showed that lumbar drain was statistically beneficial in anterior and posterior fossa defects only and not suprasellar defects. An explanation for this could be the fact the septal flaps were better fit for the suprasellar defects compared to anterior and posterior fossa defects.

In summary, there has been significant advancement in the field of skull base in regard to approach and reconstruction over recent decades. In regard to lumbar drain utilisation in the perioperative period, some disagreement remains in the literature. There has been more of a trend in recent articles to show that no lumbar drain is needed for spontaneous CSF leak repair and to some extent endoscopic skull base surgery. However, the randomised controlled trial completed at the University of Pittsburgh has shown that there is a role of lumbar drain in select cases such as anterior and posterior skull base repair in high CSF leak cases.

Dr. Shkoukani discussed the ‘Role of lumbar drain in skull base surgery’, as part of the Rhinology conference, at the ME OTO Exhibition and Conference 2019.