, Introduction
Painful traumatic trigeminal neuropathy (PTTN) is defined in the International Classification of Headache Disorders, 3rd edition (ICHD-3) as facial and/or oral pain localized to the distribution of the trigeminal nerve, resulting from trauma to the nerve and accompanied by positive and/or negative sensory signs [1]. PTTN may occur following direct or indirect injury to the trigeminal nerve, most commonly after dental procedures, maxillofacial surgery, or facial trauma [2]. While most trigeminal nerve injuries lead to transient or non-painful sensory disturbances, a subset of patients develop persistent moderate-to-severe neuropathic pain—typically with visual analog scale (VAS) scores of 5 to 8—described as burning, stabbing, and continuous in nature [3].
Clinically, PTTN is often characterized by a combination of positive and negative sensory phenomena, including hyperalgesia, allodynia, dysesthesia, numbness, and hypoesthesia within the trigeminal distribution. Reported prevalence rates vary widely, from 1.55% to 13%, reflecting differences in study populations, diagnostic criteria, and research methodologies [2]. The underlying pathophysiology is complex and multifactorial, involving peripheral and central sensitization, ganglionic remodeling, and neuroplastic changes within the trigeminal system [4]. These mechanisms contribute to the diagnostic challenges and therapeutic resistance observed in PTTN, often making its management more difficult than that of other craniofacial pain disorders [5].
Multiple therapeutic approaches have been explored, including pharmacologic agents and interventional procedures, but long-term outcomes remain suboptimal. In a longitudinal study, only one-third of patients reported meaningful clinical improvement [3]. For elderly patients with medically refractory PTTN, minimally invasive interventional techniques such as radiofrequency ablation (RFA) and gamma knife radiosurgery (GKS) may offer alternative treatment options; however, their comparative efficacy in this patient population has not been clearly established.
The present study aims to evaluate the clinical effectiveness of RFA and GKS in elderly patients with medically refractory PTTN. By analyzing a series of representative cases, we sought to elucidate the underlying etiologies, characterize clinical features, and identify factors associated with treatment responsiveness in this challenging patient cohort.
Material and Method
Between March 2018 and December 2024, we retrospectively reviewed the medical records of patients diagnosed with PTTN who underwent either RFA or GKS at Kyung Hee University Hospital. A total of 6 patients met the inclusion criteria. The mean age at the time of intervention was 63.8 years (range, 30–84 years), and the cohort comprised 5 women and one man.
The etiology of PTTN was facial trauma in 3 patients and dental procedure–related injury in the remaining 3. All patients had previously received adequate pharmacologic therapy, including agents commonly prescribed for neuropathic pain (e.g., anticonvulsants, antidepressants, or analgesics), but demonstrated insufficient pain control or unacceptable side effects. In view of their medically refractory status, patients were subsequently offered interventional treatment with either RFA or GKS.
The diagnosis of PTTN was made according to the criteria of the ICHD-3, based on clinical presentation and sensory examination. Pain severity was assessed using the VAS before and after intervention.
Ethics approval
All procedures performed in studies involving human participants were in accordance with the ethical standards of the Institutional Research Committee of Kyung Hee University Hospital (approval number: KMC IRB 1511-14) and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent for publication was obtained from each patient participated in the study.
Results
At presentation, all patients reported severe pain, with an initial VAS score ranging from 7 to 10 (mean, 8.0), despite having received prior pharmacologic therapy and nerve block interventions.
Two patients underwent RFA, and 4 received GKS. In the RF group, both patients were treated with continuous thermal ablation. In the GKS group, all patients underwent stereotactic radiosurgery targeting the anterior part of the trigeminal nerve, with a mean maximum dose of 84.5 Gy (range, 83–86 Gy).
All patients experienced pain reduction following the intervention. In the RF group, one patient’s VAS score improved from 8 to 4, whereas the other initially improved from 10 to 4 but subsequently experienced pain recurrence, with a VAS score of 9 at 3 months after RFA. In the GKS group, post-treatment VAS scores improved from 8 to 6, 7 to 4, 8 to 3, and 7 to 2, respectively. Pain outcomes and treatment durability were evaluated over a follow-up period of at least 6 months in all patients (Fig. 1). No serious treatment-related complications were observed during the follow-up period. These are summarized in Table 1.
Case illustration: refractory facial pain after repeated RFA (case II)
A 30-year-old man presented with 2-month V2-V3 electric-shock-like facial pain after facial trauma. His symptom was refractory to carbamazepine, serotonin–norepinephrine reuptake inhibitor, selective serotonin reuptake inhibitor, and tricyclic antidepressant. He had side effects from Gabapentin, nonsteroidal anti-inflammatory drugs, and opioids. Moreover, he had a VAS 9 degrees of pain. Moreover, the peripheral nerve block did not stop his pain.
RFA for the trigeminal ganglion was done under general anesthesia—60 degrees Celsius for 1 minute, and 65 degrees Celsius for another 1 minute. Right after the procedure, pain was considerably relieved. However, 3 months after the procedure, the pain recurred to a VAS of 9. Over the subsequent 26 months, 4 additional radiofrequency procedures with progressively increased parameters were undertaken, each affording only transient benefit without durable control (Fig. 2).
Discussion
PTTN remains a challenging clinical entity with limited effective treatment options and a generally poor long-term prognosis. Pharmacological therapy, typically involving antiepileptic drugs and tricyclic antidepressants, provides meaningful pain relief in only 10% to 20% of patients with PTTN [3]. This is in stark contrast to classical trigeminal neuralgia, in which up to 74% of patients achieve significant symptom control with similar pharmacologic regimens [5]. Furthermore, systemic medications are frequently associated with intolerable adverse effects, limiting their prolonged use in elderly patients [6].
In the present series, elderly patients with persistent facial pain refractory to medical management were treated with either RFA or GKS. RFA, performed in cases I and II, provided immediate symptom relief; however, one patient experienced pain recurrence at approximately three-month intervals despite escalation of lesioning intensity during repeat procedures (case II). This highlights a potential limitation of RFA in PTTN—although the initial effect can be substantial, the recurrence interval may be relatively short in certain patients. These findings are consistent with previous reports, including a 2020 systematic review demonstrating that RFA can improve pain control and reduce medication requirements in chronic facial pain, particularly when continuous and pulsed techniques are combined. While RFA is generally safe, potential complications include facial hypoesthesia, masseter muscle weakness, cheek hematoma, diminished corneal reflex, and ocular dryness [7].
In cases III–VI, GKS was performed on the basis of clinical judgment that an appropriate degree of nerve injury—guided by the response to prior RFA—would yield sufficient long-term pain control. In these patients, GKS resulted in measurable reductions in pain frequency, intensity, and duration, with partial improvements in VAS scores and quality of life, although complete pain resolution was not achieved. The mechanism of benefit may relate to targeted disruption of pathophysiological processes in PTTN, which include satellite glial cell activation, ion channel dysregulation, chemokine release, and sensitization of the trigeminal ganglion [4,6,8]. By precisely delivering high-dose radiation to the anterior part of the trigeminal nerve, GKS may attenuate abnormal nociceptive transmission and modulate central sensitization. Previous studies have similarly reported favorable outcomes of GKS in trigeminal neuropathies unresponsive to medical therapy.
Overall, our findings suggest that both RFA and GKS can provide meaningful pain reduction in elderly patients with medically refractory PTTN. RFA offers the advantage of immediate effect, but may be limited by relatively short recurrence intervals in some patients, while GKS may offer longer-lasting benefit when applied strategically based on prior interventional responses. Given the heterogeneity of clinical presentation and treatment response, individualized treatment selection remains essential. Future prospective studies with larger patient cohorts are warranted to establish standardized protocols and optimize outcomes in this patient population.
Limitations
This study has several limitations. First, the small sample size of 6 patients and the inclusion of 2 different treatment modalities—RFA and GKS—limit the generalizability of the findings. Moreover, as PTTN is an uncommon yet clinically significant complication, the single-center design further restricted the ability to recruit a larger cohort. Second, the retrospective design, relying on medical record review, is inherently vulnerable to both selection bias and information bias. Although pain severity was assessed using the VAS, other validated measures of quality of life and functional impairment were not incorporated, thereby restricting a comprehensive evaluation of treatment outcomes. To minimize potential biases, patients were selected according to the standardized diagnostic criteria outlined in the ICHD-3. Future investigations, ideally prospective multicenter studies with larger cohorts, are warranted to reduce bias and enhance the robustness and generalizability of the results. Furthermore, follow-up studies should incorporate multidimensional assessments of pain intensity and its impact on daily functioning, such as the brief pain inventory, to provide a more objective evaluation of symptom improvement.
Conclusion
Managing PTTN in elderly patients remains a considerable clinical challenge. The present study indicates that both RFA and GKS can achieve moderate pain relief in cases refractory to medical therapy. RFA offers immediate benefit but may necessitate repeated procedures due to relatively short recurrence intervals, whereas GKS provides more sustained, albeit partial, symptom improvement. Further large-scale, long-term studies are needed to define standardized treatment protocols and identify prognostic indicators for this debilitating condition. Given the heterogeneous response to interventions and the chronic nature of PTTN, individualized, multidisciplinary management strategies remain essential to optimize patient outcomes.
PDF Links
PubReader
ePub Link
XML Download
Full text via DOI
Download Citation
Print
