Objective Trigeminal neuralgia (TN) and hemifacial spasm (HFS) result from cranial nerve compression
by surrounding structures. Microvascular decompression (MVD) has proven to be an effective
treatment strategy; however, decompression of the nerve does not always lead to symptom
resolution. We aim to investigate the cause of symptoms returning in patients requiring
a repeat MVD surgery.
Methods We retrospectively reviewed the medical records of all patients undergoing revision
MVD surgeries by the senior author at our institution. Patient demographics, radiographic
data, severity of symptoms, follow-up data, records of Gamma Knife radiosurgery (GKRS),
and initial operative reports, were queried for analysis.
Results Seventeen patients were identified in our analysis, 8 cases of recurrent HFS and
9 cases of recurrent TN. Six of the cases had the same surgeon for the initial and
revision surgeries. Timing between surgeries ranged considerably between 2 weeks and
12 years. The causes of surgical failure were slippage of the Teflon pledget (n = 6/17), inflammation leading to scarring and adhesions around the nerve (n = 5/17), new site of nerve compression (n = 5/17), and no obvious anatomic cause in the final patient (n = 1/17). Seven patients had preoperative magnetic resonance imaging (MRI) available,
all of which demonstrated nerve compression. The TN cohort (n = 9) had recurrent symptoms from scarring and adhesions (n = 4/9) most commonly, followed by a new site of nerve compression (n = 3/9), slipped pledget (n = 1/9), and no obvious anatomic cause (n = 1/9). Three of the TN patients underwent GKRS prior to the revision MVD, two of
which were found to have an inflammatory reaction, though it is unclear if the adhesions
formed from the initial surgery or from GKRS. TN symptoms completely resolved in four
patients, significantly improved though still required medications in four patients,
and continued in the patient without identified anatomic nerve compression. The HFS
cohort (n = 8) had recurrent symptoms from a slipped pledget (n = 5/8), new site of nerve compression (n = 2/8), and an inflammatory reaction with scarring in the final case (n = 1/8). Symptoms of HFS resolved immediately in all but one case, which had minor
continued spasms, hypalgesia, and facial numbness. The case with continued symptoms
was complicated by postoperative meningitis, though symptoms did significantly improve
at the time of follow-up.
Conclusion Scarring and adhesion formation was the most common cause of recurrent TN. A slipped
pledget was the most common cause of continuing symptoms of HFS, likely reflective
of surgeon reluctance to apply Tisseel immediately adjacent to the cranial nerves.
Scarring did not affect HSF as it did TN cases. None of the cases that developed scarring
were performed by the same surgeon; therefore, it is unclear if the primary surgery
or, in three cases, GKRS somehow lead to scar formation. Preoperative imaging identifying
scarring as a cause of return of symptoms tend to have less of a response to revision
surgery and should prompt the neurosurgeon to consider alternative treatments such
as glycerol, radiofrequency ablation, balloon occlusion, or GKRS.
