Introduction: The superior petrosal vein (SPV) drains the superolateral part of the ipsilateral cerebellar hemisphere and pons and empties into the superior petrosal sinus. This vein is situated near the rostral cerebellopontine angle and is frequently encountered during microvascular decompression (MVD) of the trigeminal nerve. The SPV may block access to the trigeminal nerve during MVD or may rarely be the offending vessel. Complications arising from sacrifice of the SPV have been previously reported in 9.5-30% of patients.
Methods: 98 consecutive patients undergoing microvascular decompression of cranial nerve 5 or 7 between the dates of January 2006 and November 2014 were retrospectively reviewed. All patients underwent surgery at the same hospital. Division of the superior petrosal vein during surgery was recorded and statistical analysis was performed to determine if sacrifice was associated with higher complication rates.
Results: Of 98 patients undergoing MVD, 75 (76.5%) had sacrifice of the SPV at the time of surgery, 19 (19.4%) had SPV preserved, and 3 (3.1%) were revision operations. In total, 12 patients (12.2%) of patients had symptoms potentially attributable to SPV sacrifice (confusion, hydrocephalus, venous infarct, sinus thrombosis, or cerebellar edema). All 12 of these patients had the SPV taken at the time of surgery, constituting a 16% symptomatic rate. Ten of these patients had corresponding imaging findings of cerebellar or brainstem edema. None of the patients with preserved SPV were symptomatic nor had imaging changes of venous congestion.
Conclusions: Sacrifice of the SPV is often performed during MVD. However, this is associated with a significant complication rate when compared with preserving the vein. SPV sacrifice should be limited to cases where it is deemed absolutely necessary for successful cranial nerve decompression.
Patient Care: Sacrifice of the superior petrosal vein is commonly performed during microvascular decompression surgery. Patient care will be improved by raising awareness that sacrificing this vein during surgery is associated with a high rate of complications that can be avoided in most cases.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the anatomical challenges posed by the superior petrosal vein during microvascular decompression. 2) Discuss the potential role of sacrificing the petrosal vein during these procedures. 3) Understand the associated complications that may arise secondary to sacrifice of the petrosal vein, and determine when this maneuver may be necessary.