Carotid Artery Injury during Microscopic or Endoscopic Transsphenoidal Surgery

Background Internal carotid artery (ICA) injury is a rare but catastrophic complication of transsphenoidal pituitary surgery, potentially resulting in a host of deficits due to the risks of ischemia, large-distribution infarct, or even death. Our objectives were to characterize the overall incidence in a large, longitudinal, single-surgeon series of microscopic transsphenoidal operations, compare this to the previously published literature, and identify potential risk factors.

Methods Retrospective case series and review of the literature.

Results Overall volume of transsphenoidal pituitary adenoma resections by the senior author (F.B.M.) was 896 during the study period, 2002 to 2017. Within that patient population, two instances of ICA injury were identified (0.2%). In the first circumstance, a patient with Cushing’s disease had undergone three prior resections, as well as stereotactic radiosurgery, resulting in a significantly fibrous and heavily scarred operative field, and a correspondingly challenging dissection. Direct arterial transgression occurred during tumor resection, which was successfully controlled with packing, and immediately assessed via digital subtraction angiography (DSA), which confirmed patency. The patient awoke from anesthesia at his preoperative baseline and underwent an uncomplicated convalescence, with no evidence of pseudoaneurysm on subsequent follow-up angiography. The second case was a very medically complicated patient with acromegaly attributable to pituitary macroadenoma. Due to marked osteoarticular hypertrophy, definitive discrimination of the bony sella was challenging, and localization required intraoperative fluoroscopic confirmation. Following removal of the bony sellar floor, the hypervascular dura was coagulated and open sharply, resulting in brisk arterial bleeding. Collagen sponge, abdominal fat pack, and inflatable balloon were required to establish hemostasis, and the operation was aborted, after which the patient was taken for emergent CT/CTA and DSA, which demonstrated left ICA pseudoaneurysm. Postoperative neurologic examination was at baseline; however, repeat DSA on POD#3 demonstrated expansion of the pseudoaneurysm, which was assessed via balloon occlusion that was well tolerated, and treated with flow diversion and dual antiplatelet therapy. Unfortunately, follow-up DSA on POD#5 showed continued progressive pseudoaneurysm growth, and carotid occlusion was performed on POD#6 without neurologic consequence. Review of the literature demonstrated nearly 10-fold variability in the reported incidence of carotid injuries during transsphenoidal pituitary adenoma resections, with both series and meta-analyses documenting rates from 0.3 to 3% in larger populations. An inverse correlation was observed between operator volume and risk of ICA injury—a relationship that was preserved in both microscopic and endoscopic analyses (p < 0.05).

Conclusion Vascular injury is an exceedingly rare complication of transsphenoidal pituitary surgery. Although potentially disastrous, good neurologic outcomes may be obtained, and we recommend judiciously arterial packing, to avoid excessively ICA compression. Immediate DSA is mandatory to assess vessel patency and secondary complications such as pseudoaneurysm. Operator inexperience appears to be the most significant risk factor, with comparably low rates of injury obtained by highly experienced surgeons, independent of technique.

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