Characteristics of the Study Patients
Between January 2018 to January 2022, 151 patients with recurrent TN underwent CT-Guided PBC at the department of pain management. One patient who had the characteristic atypical pear-shaped balloon was excluded. Five patients (3.3%) had a history of allergy to carbamazepine. The other 145 patients were either refractory or intolerant to carbamazepine. Detailed characteristics of the 150 enrolled patients are shown in Table 1. The median age (range) was 66 (36, 87) years with a median disease duration (length of history before PBC) of 7 years. 130 (86.7%) patients were in the effective group and 20 (13.3%) patients were in the ineffective group. There were no significant differences in aspects of age, gender, BMI, comorbidities, duration of disease, time to recurrence, baseline NRS score, carbamazepine dose pre-PBC, affected side of TN, distribution of pain, and BNI facial hypesthesia scale after the last surgery between the two groups. Fourteen (10.8%) patients in the effective group only experienced RFT before, which was significantly lower than that in the ineffective group (6, 30%, p=0.019).
Operation Variables, Efficacy
The NRS score immediately after PBC in the effective group was much lower than that in the ineffective group (2 [range: 0,4] vs 7 [range: 6,8], P < 0.01). In the effective group, 121 patients (93.1%) experienced an immediate significant reduction in NRS score after the procedure, and the dose of the preoperative drug was gradually decreased. In 9 patients (6.9%), there was no significant decrease in NRS scores immediately after PBC, and these patients needed to continue treatment with medications. The pain began to gradually decrease at an average of 4 days (range 2 to 12 days) after PBC. They achieved pain relief within one month after PBC and stopped taking drugs. Among these 130 patients, 2 experienced recurrence at 18 and 22 months after PBC procedure. Then both of them underwent repeated PBC and achieved pain relief instantly.
Within one month after PBC, the total efficacy of PBC on recurrent TN following TN-related surgeries was 86.7%. The efficacies of PBC after MVD alone, PBC alone, RFT alone, GKRS alone and GR alone were 90.9%, 77.8%, 70.0%, 92.9% and 83.3%, respectively. Besides, 88.9% patients underwent no less than 2 surgeries before achieving pain relief within one month after PBC.
Univariate analysis for recurrent TN outcome after PBC
Univariate logistic regression was used to determine the association between age, gender, BMI, comorbidities, duration of disease, time to recurrence, baseline NRS score, carbamazepine dose pre-PBC, affected side of TN, distribution of pain, history of previous surgeries for TN, BNI facial hypesthesia scale after the last surgery and TN outcome. The results showed that previous RFT was a significant predictor of poor outcome for recurrent TN following PBC (OR 0.28, 95%CI 0.09-0.85, P=0.03) (Table 3).
Relationship between preoperative variables and recurrent TN outcome after PBC in different models
We also employed multivariate logistic regression to demonstrate the association between previous RFT and TN outcome (Table 4). In the adjusting I (adjusting for age and gender) and II (adjusting for age, gender, BMI, comorbidities, duration of disease, time to recurrence, baseline NRS score, carbamazepine dose pre-PBC, affected side of TN, distribution of pain, BNI facial hypesthesia scale after the last surgery) models, the previous RFT was considered to be a significant predictor of poor outcome at 1 month’s follow-up (adjust I, OR 0.28 ; adjust II, OR 0.30, respectively, both P <0.05).
Among the 20 patients who failed to respond to PBC, two underwent GKRS at 4, 5 weeks after PBC at other hospitals. The remaining 18 patients underwent RFT at our hospital. All of the 20 patients got satisfactory pain relief after GKRS or RFT.
There were no significant differences in incidence of trigeminal cardiac reflex, operation duration, balloon volume, compression time, herpes simplex and diplopia between the two groups. Patients developed herpes simplex on postoperative day 2-3, and the symptom lasted for 1 week. None of the patients in this study had facial swelling, corneal anesthesia, infection or hematoma at puncture site, intracranial hemorrhage, intracranial infection or death. Forty-five patients (34.6%) suffered masseter weakness in the effective group and 2 (10.0%) suffered that in the ineffective group (P=0.04, table 2). In addition, 119 (91.5%) patients developed facial numbness in the effective group compared to 4 (20.0%) in the ineffective group (P=0.00, table 2).