A Blinded, Case-Control Trial Assessing the Value of Steady State Free Precession Magnetic Resonance Imaging in the Diagnosis of Trigeminal Neuralgia

Percutaneous glycerol rhizolysis of the trigeminal ganglion for the treatment of idiopathic and classic trigeminal neuralgia: Outcomes and complications

BACKGROUND AND PURPOSE

Patients with idiopathic trigeminal neuralgia (TN) with absent arterial contact or venous contact only and classic TN with morphological changes of the trigeminal nerve secondary to venous compression are not routinely recommended microvascular decompression at our institution. In patients with these anatomical subtypes of TN, limited data exists describing the outcomes of percutaneous glycerol rhizolysis (PGR) of the trigeminal ganglion (TG).

METHODS

We performed a retrospective single-center cohort study and analyzed outcomes and complications after PGR of the TG. Clinical outcome after PGR of the TG was assessed via the Barrow Neurological Institute (BNI) Pain Scale.

RESULTS

Forty-five patients underwent a total of 66 PGRs of the TG. At short-term follow-up, 58 procedures (87.9%) resulted in a BNI score of I (i.e., freedom from pain without medication). At a median follow-up of 3.07 years, 18 procedures (27.3%) resulted in a BNI score of I, 12 procedures (18.1%) resulted in BNI score of IIIa, and 36 procedures (54.5%) resulted in a BNI score of IIIb-V. The median length of freedom from pain without medication was 1.5 years. Eighteen procedures (27.3%) caused hypesthesia and two (3.0%) caused paresthesias. There were no serious complications.

CONCLUSION

In patients with these anatomical subtypes of TN there was a high rate of short-term pain relief for the first 1-2 years and thereafter a large proportion of patients experienced pain relapse. In this patient group, PGR of the TG represents a safe procedure that is efficacious in the short term.

ACR Appropriateness Criteria® Cranial Neuropathy: 2022 Update

Cranial neuropathy can result from pathology affecting the nerve fibers at any point and requires imaging of the entire course of the nerve from its nucleus to the end organ in order to identify a cause. MRI with and without intravenous contrast is often the modality of choice with CT playing a complementary role. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Pain Outcomes Following Microvascular Decompression for Drug-Resistant Trigeminal Neuralgia: A Systematic Review and Meta-Analysis

BACKGROUND

Microvascular decompression (MVD) is a potentially curative surgery for drug-resistant trigeminal neuralgia (TN). Predictors of pain freedom after MVD are not fully understood.

OBJECTIVE

To describe rates and predictors for pain freedom following MVD.

METHODS

Using preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, PubMed, Cochrane Library, and Scopus were queried for primary studies examining pain outcomes after MVD for TN published between 1988 and March 2018. Potential biases were assessed for included studies. Pain freedom (ie, Barrow Neurological Institute score of 1) at last follow-up was the primary outcome measure. Variables associated with pain freedom on preliminary analysis underwent formal meta-analysis. Odds ratios (OR) and 95% confidence intervals (CI) were calculated for possible predictors.

RESULTS

Outcome data were analyzed for 3897 patients from 46 studies (7 prospective, 39 retrospective). Overall, 76.0% of patients achieved pain freedom after MVD with a mean follow-up of 1.7 ± 1.3 (standard deviation) yr. Predictors of pain freedom on meta-analysis using random effects models included (1) disease duration ≤5 yr (OR = 2.06, 95% CI = 1.08-3.95); (2) arterial compression over venous or other (OR = 3.35, 95% CI = 1.91-5.88); (3) superior cerebellar artery involvement (OR = 2.02, 95% CI = 1.02-4.03), and (4) type 1 Burchiel classification (OR = 2.49, 95% CI = 1.32-4.67).

CONCLUSION

Approximately three-quarters of patients with drug-resistant TN achieve pain freedom after MVD. Shorter disease duration, arterial compression, and type 1 Burchiel classification may predict more favorable outcome. These results may improve patient selection and provider expectations.

Trigeminal Nerve Compression Without Trigeminal Neuralgia: Intraoperative vs Imaging Evidence

BACKGROUND

While high-resolution imaging is increasingly used in guiding decisions about surgical interventions for the treatment of trigeminal neuralgia, direct assessment of the extent of vascular contact of the trigeminal nerve is still considered the gold standard for the determination of whether nerve decompression is warranted.

OBJECTIVE

To compare intraoperative and magnetic resonance imaging (MRI) findings of the prevalence and severity of vascular compression of the trigeminal nerve in patients without classical trigeminal neuralgia.

METHODS

We prospectively recruited 27 patients without facial pain who were undergoing microvascular decompression for hemifacial spasm and had undergone high-resolution preoperative MRI. Neurovascular contact/compression (NVC/C) by artery or vein was assessed both intraoperatively and by MRI, and was stratified into 3 types: simple contact, compression (indentation of the surface of the nerve), and deformity (deviation or distortion of the nerve).

RESULTS

Intraoperative evidence of NVC/C was detected in 23 patients. MRI evidence of NVC/C was detected in 18 patients, all of whom had intraoperative evidence of NVC/C. Thus, there were 5, or 28% more patients in whom NVC/C was detected intraoperatively than with MRI (Kappa = 0.52); contact was observed in 4 of these patients and compression in 1 patient. In patients where NVC/C was observed by both methods, there was agreement regarding the severity of contact/compression in 83% (15/18) of patients (Kappa = 0.47). No patients exhibited deformity of the nerve by imaging or intraoperatively.

CONCLUSION

There was moderate agreement between imaging and operative findings with respect to both the presence and severity of NVC/C.

Development and Evaluation of a Preoperative Trigeminal Neuralgia Scoring System to Predict Long-Term Outcome Following Microvascular Decompression

BACKGROUND

Microvascular decompression (MVD) can be an effective intervention for trigeminal neuralgia (TN); however, an optimal system for patient selection and surgical outcome prediction has not been defined.

OBJECTIVE

To develop and validate a preoperative TN grading system for the prediction of long-term pain relief after MVD.

METHODS

This retrospective cohort study included consecutive patients suffering unilateral TN who underwent MVD with >18-mo follow-up. A grading system was formulated using 3 previously validated preoperative characteristics. The primary end-point was long-term, pain-free status without use of medication. Ability to predict pain-free status was analyzed by multiple regression and assessed by area under the receiver operating characteristic curve (AUC). Clinical utility to predict MVD success and reduce unnecessary surgeries was assessed by decision-curve analysis.

RESULTS

Of 208 patients analyzed, 73% were pain-free without medication at >18-mo follow-up. Pain-free status was predicted by classical TN type, positive response to carbamazepine and/or oxcarbazepine, and presence and nature of neurovascular compression demonstrated on MRI (all P < .01). The TN grading system demonstrated good discriminatory ability for prediction of pain-free status (AUC 0.85, 95% CI 0.80-0.91). Decision-curve analysis demonstrated a net reduction of 20 cases likely to be unsuccessful per 100 patients evaluated with this grading system above a decision threshold of 80%.

CONCLUSION

This TN grading system reliably predicts long-term pain-free status without medications following MVD. The use of the TN grading system as part of a comprehensive work-up may reduce the number of unsuccessful operations.

Significance of degree of neurovascular compression in surgery for trigeminal neuralgia

OBJECTIVE

The aim of this study was to identify preoperative imaging predictors of surgical success in patients with classic trigeminal neuralgia (cTN) undergoing microvascular decompression (MVD) via retrospective multivariate regression analysis.

METHODS

All included patients met criteria for cTN and underwent preoperative MRI prior to MVD. MR images were blindly graded regarding the presence and severity (i.e., mild or severe) of neurovascular compression (NVC). All patients were contacted by telephone to determine their postoperative pain status.

RESULTS

A total of 79 patients were included in this study. Sixty-two patients (78.5%) were pain-free without medication following MVD. The following findings were more commonly observed with the symptomatic nerve when compared to the contralateral asymptomatic nerve: NVC (any form), arterial compression alone, NVC along the proximal trigeminal nerve, and severe NVC (p values < 0.0001). The only imaging variable that was a statistically significant predictor of being pain-free without medication following MVD was severe NVC. Patients with severe NVC were 6.36 times more likely to be pain-free following MVD compared to those without severe NVC (p = 0.007).

CONCLUSIONS

In patients with cTN undergoing MVD, severe NVC on preoperative MRI is a strong predictor of an excellent surgical outcome.

Imaging evaluation of trigeminal neuralgia

Trigeminal neuralgia is a debilitating pain syndrome in the sensory distribution of the trigeminal nerve. Compression of the cisternal segment of the trigeminal nerve by a vessel, usually an artery, is considered the most common cause of trigeminal neuralgia. A number of additional lesions may affect the trigeminal nerve anywhere along its course from the trigeminal nuclei to the most peripheral branches to cause facial pain. Relevant differential considerations are reviewed starting proximally at the level of the brainstem.