Neurological surgery is a broad field encompassing a wide range of disorders throughout the body. As with any surgical subspecialty neurosurgery is prone to its own set of unique complications. Some of the more common complications in these patients are often recognized and treated by physicians outside of neurosurgery. The goal of this chapter is to highlight a few of the more common neurosurgical complications and give the hospitalist a better understanding of how to evaluate and treat these patients. This chapter is subdivided into intracranial and spine complications.
The brain is enclosed within the meninges and is not, in the usual situation, communicative with the external environment. Obviously a neurosurgical procedure involving an open craniotomy creates an event in which the brain is exposed to air. At the end of a craniotomy, the closure of the dura, reattachment of the bone flap and reapproximation of the skin unavoidably seals at least a small amount of air inside. In response, the partial pressure differences of gaseous air will cause reabsorption back into the blood and tissues. In the interim, however, the collection of air around the brain can cause dysfunction and even injury. A minor amount of trapped pneumocephalus is usually inconsequential. A voluminous amount of pneumocephalus, however, can cause altered mental status and a depressed level of consciousness. In addition when a passageway to the bony sinuses is inadvertently or purposely created (such as an opening into the frontal sinus with the fashioning of a bone flap), there occurs the possibility of a one-way valve wherein air enters the cranium and is not allowed to escape. Under these situations, pneumocephalus can accumulate over time and occur under pressure hastening and magnifying the neural symptoms even unto coma or death.
Pneumocephalus can occur after any craniotomy or endonasal surgery. Even minor twist drill hole procedures can produce a minor amount of intracranial air (this is almost uniformly benign). Suspicion of this diagnosis should be considered when a postoperative patient does not return to their baseline mentation. An urgent/emergent CT scan is the imaging study of choice and will reveal the amount of air along with the point of entry in the occurrence of “sucking” pneumocephalus from an opened frontal sinus, ethmoid air cell, sphenoid sinus, etc. Severe pneumocephalus produces an “Mt Fuji sign” from the sagging frontal lobes (Figure 64-1). When diagnosed and followed, a “brow-up” skull film will demonstrate the bubble of intracranial air quite well and can be compared day to day for proof of improvement (Figure 64-2). Use of this imaging study significantly reduces the amount of total radiation exposure over serial CT scans.
“Mount Fuji Sign.” While not classic for the typical peaked pneumocephalus, note the compressive nature of the air collection at the surgical site.