Intraoperative neurophysiologic monitoring during aortic arch surgery

OBJECTIVE

To evaluate the ability of intraoperative neurophysiologic monitoring (IONM) during aortic arch reconstruction with hypothermic circulatory arrest (HCA) to predict early (<48 hours) adverse neurologic events (ANE; stroke or transient ischemic attack) and operative mortality.

METHODS

This was an observational study of aortic arch surgeries requiring HCA from 2010 to 2018. Patients were monitored with electroencephalogram (EEG) and somatosensory evoked potentials (SSEP). Baseline characteristics and postoperative outcomes were compared according to presence or absence of IONM changes, which were defined as any acute variation in SSEP or EEG, compared with baseline. Multivariable logistic regression analysis was used to assess the association of IONM changes with operative mortality and early ANE.

RESULTS

A total of 563 patients underwent aortic arch reconstruction with HCA and IONM. Of these, 119 (21.1%) patients had an IONM change, whereas 444 (78.9%) did not. Patients with IONM changes had increased operative mortality (22.7% vs 4.3%) and increased early ANE (10.9% vs 2.9%). In multivariable analysis, SSEP changes were correlated with early ANE (odds ratio [OR], 4.68; 95% confidence interval [CI], 1.51-14.56; P = .008), whereas EEG changes were not (P = .532). Permanent SSEP changes were correlated with early ANE (OR, 4.56; 95% CI, 1.51-13.77; P = .007), whereas temperature-related SSEP changes were not (P = .997). Finally, any IONM change (either SSEP or EEG) was correlated with operative mortality (OR, 5.82; 95% CI, 2.72-12.49; P < .001).

CONCLUSIONS

Abnormal IONM events during aortic arch reconstruction with HCA portend worse neurologic outcomes and operative mortality and have a negative predictive value of 97.1%. SSEP might be more sensitive than EEG for predicting early ANE, especially when SSEP changes are permanent.

Endoscopic transsphenoidal drainage of a petrous apex cholesterol granuloma using a frontal sinus nasal stent: a case report with long term follow up

BACKGROUND

Cholesterol granulomas of the petrous apex are benign cysts affecting 0.6 patients per 1 million. The pathophysiology involves cholesterol crystals and lipids that are surrounded by giant cells. The cholesterol deposits induce an inflammatory response likely from acute hemorrhage leading to the formation of a fibrous capsule. The capsule expands over time compressing nearby cranial nerves (VI-VIII), which can cause worsening symptoms. Surgical resection has been shown to provide excellent improvement in symptoms. Historically, open approaches such as the infracochlear, infralabyrinthine, and middle fossa have been used. Herein we present a case showing the feasibility and clinical utility of using an endoscopic endonasal transclival approach for treatment of these tumors.

CASE

A 44-year-old female presented with history of intermittent double vision, dizziness, nausea, and headaches for 3 years. She developed a partial left CN6 palsy with significant diplopia and episodes of left facial weakness. The worsening symptoms prompted presentation to the ED where MRI and CT scan revealed a left petrous apex lesion (1.8 × 1.7 cm) with hyperintensity on T1 and T2 imaging, suggestive of cholesterol granuloma. She underwent an endoscopic transclival resection of the lesion: drainage of left petrous apex cholesterol granuloma and stent placement from left petrous apex into sphenoid sinus (novel technique). This was done to allow continued communication and drainage of the tumor bed from the petrous apex into the sphenoid sinus with the intent to minimize the risk of recurrence. At the postop visit both 6th nerve palsy and diplopia had resolved. Imaging is stable 2 years after the surgery.

DISCUSSION

The placement of the stent in this case was done to prevent symptom recurrence. 11% of patients that do not receive a stent will have symptom recurrence within one year. From the historical literature, only 4% of patients who had stent placement developed cyst recurrence or expansion on follow-up imaging. Stent placement has been shown to prevent cyst enlargement within the first few months after surgery. We demonstrate that the endoscopic endonasal transclival approach provided good visualization of the tumor, allowed for an adequate working window for resection, and provided a sufficient approach for stent placement.