Recalcitrant Pelvic Pain: Evaluating the Effectiveness of Radiofrequency Ablation for Pudendal, Genitofemoral, and Ilioinguinal Neuropathy

1. Introduction

Chronic pelvic pain syndrome (CPPS), defined as non-malignant, non-cyclical pelvic pain lasting at least six months, is a prevalent and disabling condition that affects both men and women, often accompanied by cognitive, behavioral, or social challenges [1,2,3]. Women are disproportionately affected, with prevalence estimates reaching 26–27% globally and roughly 15% in the United States [1,4,5,6]. The wide spectrum of causes necessitates multidisciplinary care involving gynecology, urology, colorectal surgery, and pain management, yet the absence of universally accepted diagnostic criteria complicates both diagnosis and treatment, often resulting in delayed recognition and worsened chronicity [7].

One major neuropathic contributor to CPPS is pudendal neuropathy, characterized by genital, rectal, and perineal pain, with prevalence estimated at 1% in the general population and up to 20% in women [7]. The pudendal nerve, arising from sacral roots S2–S4, supplies sensory and motor innervation to the perineal region [8]. Pudendal neuralgia may result from iatrogenic injuries such as pelvic organ prolapse repair, childbirth, repetitive trauma (e.g., cycling), or systemic conditions including diabetes, multiple sclerosis, and viral infections [9,10,11,12,13,14]. Treatment strategies range from pharmacologic and physical therapies to perineural steroid injections [15,16,17,18]. Nevertheless, repeated injections often lose efficacy, while decompression surgery risks further nerve damage and scarring [13,19]. Pulsed radiofrequency ablation (pRFA) has emerged as a minimally invasive alternative, delivering high-intensity current in short bursts to modulate aberrant signaling without thermal injury [20,21,22,23,24]. Case reports, pilot studies, and a randomized trial suggest pRFA provides superior and more durable pain relief compared to steroid injections [25,26,27,28].

Neuropathic pain also arises from entrapment of the ilioinguinal and genitofemoral nerves, which originate from the lumbar plexus and are vulnerable to trauma during pelvic or hernia surgery, as well as repetitive strain [29,30,31]. Such neuralgias are frequently underdiagnosed, with symptoms that mimic other pelvic conditions, adding to the complexity of CPP. First-line approaches include medications, physical therapy, and image-guided corticosteroid injections [1,6,32,33]. While nerve blocks can provide diagnostic clarity and short-term relief, their benefits diminish with repeated use. Neurectomy may be considered in refractory cases but is invasive, not widely available, and subject to recurrence [34,35,36]. In this context, continuous radiofrequency ablation (cRFA) has gained interest, with early case series and small randomized trials showing prolonged analgesia in ilioinguinal neuralgia [37,38,39]. Nevertheless, evidence for genitofemoral nerve ablation remains limited to isolated case reports and small cohorts [30,40].

Together, these observations underscore the need for minimally invasive, durable interventions for pelvic neuropathies. This study evaluates CT-guided pRFA for pudendal neuralgia and cRFA for ilioinguinal and genitofemoral neuralgias, comparing outcomes in pain scores, analgesic use, quality of life, and safety, with the aim of advancing treatment strategies for refractory chronic pelvic pain.

2. Materials and Methods

2.1. Study Design

This retrospective cohort study, approved by the Institutional Review Board (IRB) with a waiver of informed consent, analyzed a consecutive cohort of patients who underwent pudendal nerve pRFA at a single tertiary care hospital, based on electronic health record chart reviews from April 2016 to August 2024. Patients were referred by physical medicine and rehabilitation physicians from a pelvic pain clinic, and the diagnoses were based on multiple criteria, including clinical findings of pudendal neuralgia, previous response to pelvic floor therapy and perineural steroid injection. All participants had previously received medical therapy and magnetic resonance neurography (MRN) of the lumbosacral plexus.

The inclusion criteria were adult patients (≥ 18 years) of all genders, clinically diagnosed with pelvic neuralgia, having received medical therapy and at least one injection before their first RFA. Exclusion criteria included patients who did not undergo initial medical therapy, patients with less than six months of follow-up post-procedure, and those with incomplete electronic health records. Selection methodology can be illustrated in Figure 1.

2.2. CT-Guided Procedures

All ablation procedures followed a standardized process. Patients were brought to the CT suite by a procedural nurse, placed on cardiac and oxygen monitoring, positioned prone, and a pre-procedural timeout was performed. Procedures were performed under CT fluoroscopy guidance with conscious sedation. Sedation typically included fentanyl (average 81–83 ± 43–58 µg) and midazolam (1.2–1.3 ± 0.65–0.76 mg), titrated for patient comfort, with two patients in each cohort opting to forego sedation.

Superficial anesthesia was provided with 1% lidocaine before needle placement. Using radiopaque markers and intermittent CT guidance, a 22 G coaxial needle was advanced to the target nerve. For pudendal procedures, the needle was positioned adjacent to the pudendal nerve in Alcock’s canal, identified as the most posterior structure in the pudendal neurovascular bundle beneath the sacrotuberous ligament, with fascicular architecture and intermediate density confirming its location. For ilioinguinal procedures, the needle was advanced to the fascial plane between the internal oblique and transversus abdominis muscles near the anterior superior iliac spine. For genitofemoral procedures, the target was the anterior surface of the psoas major, lateral to the external iliac artery, with CT confirming fascicular structure and density. Needle placement was confirmed in all cases by injection of 1 ml of dilute water-soluble iodinated contrast (Isovue 180 or 200).

Ablation probes were advanced through the needles, followed by sensory and motor stimulation at 2–3 V. For pudendal procedures, pulsed RFA (pRFA) was performed at 42–43°C for 120 seconds, followed by injection of 5 ml of anesthetic-steroid mixture (2 ml 1% lidocaine, 2 ml 0.5% bupivacaine, 1 ml dexamethasone 4 mg/ml). For ilioinguinal and genitofemoral procedures, continuous RFA (cRFA) was performed at 79–80°C for 90 seconds, followed by the same anesthetic-steroid injectate. The choice of technique reflected anatomical and functional considerations: the pudendal nerve is a mixed sensory–motor nerve in close proximity to sphincteric structures, making pRFA preferable to avoid permanent injury, whereas the ilioinguinal and genitofemoral nerves are primarily sensory and more superficial, allowing safe thermal lesioning with cRFA for longer-lasting relief.

Procedure duration averaged 94 ± 46 minutes for pudendal cases and 49 ± 39 minutes for ilioinguinal/genitofemoral cases, including setup, sedation, and time-out protocols. Needle insertion-to-removal time ranged 5–10 minutes for pudendal and 5–20 minutes for ilioinguinal/genitofemoral cases. Technical success was achieved in all patients, defined as accurate needle placement confirmed with contrast injection and attainment of target ablation parameters. No immediate complications were observed. Demographic data, clinically relevant history, imaging studies, and details of medical and surgical therapy were abstracted from patients’ medical records. Ablation of respective pudendal nerves can be seen in Figure 2. Ablation of respective ilioinguinal and genitofemoral nerves can be seen in Figure 3 and Figure 4.

2.3. Follow-Ups

Clinical outcomes for all patients were evaluated using retrospective chart reviews and prospective telephone questionnaires. Pain severity was assessed with the validated 10-point Visual Analog Scale (VAS) at 4 weeks, 6 weeks, 3 months, and 6 months following ablation. Duration of pain relief was defined as the time from the procedure to the recurrence of pain, with the lowest reported VAS score during each interval also recorded. For patients undergoing multiple ablation procedures, outcomes were analyzed chronologically by procedure date. Data on analgesic use and patient-reported quality-of-life changes were collected at the same intervals to capture broader treatment effects.

2.4. Statistics

All statistical analyses were conducted by a faculty statistician. Pain relief durations and lowest pain scores were compared across steroid injections, pRFA, and cRFA using a linear mixed model that accounted for within-patient clustering, with log (duration + 1) transformation applied to address skewness. Ad-hoc multiple comparisons were performed with Tukey adjustment. Pearson correlation coefficients examined the relationship between symptom duration and treatment outcomes. A significance threshold of p < 0.05 was used. Additional analyses, including ANOVA, chi-square tests, and Student’s t-tests, were conducted using Prism GraphPad software.

3. Results

3.1. Patient Characteristics and Demographics

A total of 49 patients with pudendal neuropathy, 15 with ilioinguinal neuropathy, and 14 with genitofemoral neuropathy met inclusion criteria, forming the final combined cohort of 78 patients for analysis. Among the 49 patients with pudendal neuralgia, 186 procedures were performed over an average follow-up of 8.82 ± 2.39 months. The mean age was 61.7 ± 14.1 years with a BMI of 26.3 ± 4.9; 30 were female and 19 male. Thirty-one underwent one ablation, 13 had two, 6 received three, and 2 patients underwent four procedures for recalcitrant pain. The most recent pain exacerbation prior to pRFA had persisted for 8.12 ± 1.34 months. All patients received at least one prior CT-guided perineural injection (mean 2.10 ± 1.65, range 1–8).

In the ilioinguinal group (n = 15), the mean age was 57.3 ± 14.1 years, with a BMI of 28.8 ± 7.0; 9 were female and 6 male. A total of 47 procedures were performed (8 left, 5 right, 2 bilateral), with an average pain duration prior to cRFA of 7.21 ± 1.12 months.In the genitofemoral group (n = 14), the mean age was 59.7 ± 18.5 years, with a BMI of 29.9 ± 9.2; 8 were female and 6 male. Forty-nine procedures were performed (4 left, 6 right, 4 bilateral), with pain duration averaging 7.47 ± 0.93 months prior to cRFA.

3.2. MRN Findings

Pre-procedural MR neurography was available for all patients. Among pudendal cases (n = 49), 51.0% (n = 25) demonstrated no abnormalities; 16.3% (n = 8) showed nerve thickening/asymmetry; 12.2% (n = 6) demonstrated T2 hyperintensity; 18.4% (n = 9) showed perineural scarring/fibrosis at Alcock’s canal; and 26.5% (n = 13) displayed pelvic muscle atrophy.

For ilioinguinal patients (n = 15), 46.7% (n = 7) had no abnormalities; 20.0% (n = 3) showed nerve thickening; 13.3% (n = 2) demonstrated T2 hyperintensity; 20.0% (n = 3) had perineural fibrosis near the inguinal canal; and 26.7% (n = 4) exhibited adjacent abdominal wall muscle atrophy. For genitofemoral patients (n = 14), 50.0% (n = 7) had no abnormalities; 14.3% (n = 2) showed nerve thickening; 14.3% (n = 2) demonstrated T2 hyperintensity; 21.4% (n = 3) had perineural scarring near the psoas tunnel; and 28.6% (n = 4) showed iliopsoas muscle atrophy. Table 1, Table 2 and Table 3 provide detailed demographic, procedural, and imaging characteristics.

3.3. Pain Response

For pudendal neuropathy, initial baseline pain before intervention averaged 5.92 ± 2.78 amongst the cohort. The lowest post-procedure pain scores were 1.85 ± 3.54 following the first steroid injection, 1.64 ± 1.73 after the most recent injection, and 1.75 ± 2.21 after pRFA. All interventions yielded significant pain reductions compared to baseline (p < 0.0001). However, differences between pRFA and steroid injections did not reach statistical significance (p = 0.992 vs. first injection; p = 0.995 vs. most recent injection).

For ilioinguinal neuropathy, mean baseline pain was 6.87 ± 1.25. After the first steroid injection, pain decreased to 2.23 ± 1.92 (p < 0.0001) but increased to 3.80 ± 1.70 after the most recent injection (p < 0.0001 vs. baseline). Following the first cRFA, scores improved further to 1.73 ± 1.28 (p < 0.0001), representing the most effective intervention. The second cRFA produced a score of 3.33 ± 1.21, which was not significantly different from the first ablation (p = 0.2585).

For genitofemoral neuropathy, baseline pain was 6.36 ± 1.34. Scores decreased to 2.57 ± 1.70 following the first steroid injection (p < 0.0001) and rose to 3.43 ± 1.16 after the most recent injection (p < 0.0001 vs. baseline). After the first cRFA, pain decreased further to 2.36 ± 1.08 (p = 0.0007 vs. most recent injection). The second cRFA yielded a score of 3.43 ± 0.98, which was not significantly different compared to the first ablation (p = 0.5608).

3.4. Duration of Pain Relief

The duration of pain relief was evaluated over a minimum 6-month follow-up for all patients (Figure 5). Among those with pudendal neuropathy, mean duration of improvement following pRFA was 9.48 ± 9.52 weeks, significantly longer than the 3.98 ± 3.56 weeks observed after the first steroid injection and 3.32 ± 3.21 weeks after the most recent injection (p < 0.0001 for both comparisons).

For the ilioinguinal group, mean duration of benefit following the first steroid injection was 2.71 ± 1.20 weeks, decreasing slightly to 2.43 ± 0.85 weeks after the most recent injection (p > 0.9999). Following the first cRFA, duration of relief increased markedly to 21.76 ± 19.04 weeks (p = 0.0002 vs. most recent injection). A second cRFA produced a shorter duration of 10.75 ± 3.43 weeks, though this was not significantly different from the first ablation (p = 0.3600).

For the genitofemoral group, mean duration of improvement was 2.80 ± 0.94 weeks after the first steroid injection and 2.87 ± 1.19 weeks after the most recent injection (p > 0.9999). Following the first cRFA, duration extended significantly to 17.68 ± 12.98 weeks (p < 0.0001 vs. most recent injection). The second cRFA averaged 8.25 ± 2.63 weeks, which again was not significantly different compared to the first ablation (p = 0.1488).

Figure 6. Duration of Pain Relief in Weeks Following Steroid Injection and RFA by Nerve Ablated. (a) Pudendal ablation; (b) Ilioinguinal ablation; (c) Genitofemoral ablation.

Figure 6. Duration of Pain Relief in Weeks Following Steroid Injection and RFA by Nerve Ablated. (a) Pudendal ablation; (b) Ilioinguinal ablation; (c) Genitofemoral ablation.

3.5. Quality of Life

For pudendal neuropathy, 36 patients had documented quality-of-life (QoL) scores following pRFA, measured with 10-point Likert scales where 10 indicated maximum improvement in function, pain tolerance, and comfort. Significant improvements were observed at 4 weeks (p = 0.0001), 6 weeks (p = 0.0003), and 3 months (p = 0.0016), while a non-significant benefit persisted at 6 months (p = 0.0726).

For ilioinguinal neuropathy, QoL scores were available for 24 patients. Baseline mean QoL was 3.89 ± 1.59, which improved significantly to 6.32 ± 1.11 at 4 weeks (p < 0.0001) and 6.21 ± 1.18 at 6 weeks (p < 0.0001). At 3 months, scores declined slightly to 5.79 ± 1.40 but remained significantly higher than baseline (p = 0.0023). By 6 months, scores further decreased to 4.84 ± 0.96, showing no significant difference compared to baseline (p = 0.124).

For genitofemoral neuropathy, baseline QoL was 3.21 ± 1.13. Scores improved significantly at 4 weeks (5.32 ± 1.20, p < 0.0001) and 6 weeks (5.26 ± 0.93, p < 0.0001), with a modest decline by 3 months (4.89 ± 0.88, p = 0.0017). At 6 months, scores decreased further to 3.74 ± 1.10, with no significant difference from pre-intervention levels (p = 0.112).

Figure 7. Quality of Life Scores Following cRFA by Nerve Ablated. (a) Pudendal ablation; (b) Ilioinguinal ablation; (c) Genitofemoral ablation.

Figure 7. Quality of Life Scores Following cRFA by Nerve Ablated. (a) Pudendal ablation; (b) Ilioinguinal ablation; (c) Genitofemoral ablation.

3.6. Analgesic Use

For pudendal neuropathy, 33 patients had documented analgesic use tracked for up to six months following pRFA. Patients rated their use of oral pain medications and topical analgesics on a 0–2 Likert scale, where 0 indicated no need for analgesics, 1 represented continuation of the pre-procedure regimen, and 2 indicated doubling of analgesic need. Significant reductions in analgesic use were reported at 4 weeks (p = 0.0014), 6 weeks (p = 0.0045), and 3 months (p = 0.0110), with a non-significant decrease persisting at 6 months (p = 0.1683).

For ilioinguinal neuropathy, cRFA produced significant short-term reductions in analgesic use compared to baseline (100%). At 4 weeks, usage decreased to 86.67% ± 8.16% (p < 0.0001) and remained low at 87.33% ± 9.61% at 6 weeks (p < 0.0001). By 3 months, use began to rise toward baseline at 90.67% ± 7.04% (p = 0.0049), and at 6 months it reached 94.67% ± 6.40%, showing no significant difference compared to pre-procedure levels (p = 0.2458).

For genitofemoral neuropathy, baseline analgesic use was also 100%. After cRFA, usage decreased to 86.43% ± 7.45% at 4 weeks (p < 0.0001) and 90.00% ± 6.79% at 6 weeks (p = 0.0002). By 3 months, usage rose to 92.14% ± 5.79% (p = 0.0045), and by 6 months, returned to 95.71% ± 5.14%, which was not significantly different from baseline (p = 0.2800).

Figure 8. Reported Analgesic Use Over Time Following Ablation by Nerve Type. (a) Pudendal ablation; (b) Ilioinguinal ablation; (c) Genitofemoral ablation.

Figure 8. Reported Analgesic Use Over Time Following Ablation by Nerve Type. (a) Pudendal ablation; (b) Ilioinguinal ablation; (c) Genitofemoral ablation.

3.7. Correlations

Across all three nerve groups, there was no significant correlation between treatment timing and outcomes. In pudendal neuropathy, neither symptom duration nor interval from last injection to pRFA correlated with post-procedure pain scores or duration of relief. Similarly, for ilioinguinal and genitofemoral neuropathies, no associations were observed between symptom duration or timing of prior injections and cRFA outcomes. These findings collectively suggest that the timing of intervention does not significantly influence the efficacy of radiofrequency ablation.

3.8. Complications

Across all procedures, complications were generally mild and self-limiting, with no patient requiring further intervention. In the pudendal group (n = 49), nine patients developed transient symptoms: three experienced mild perineal numbness resolving in 3–4 days, four reported injection site soreness subsiding within 3–5 days, and two noted transient bowel or bladder urgency/difficulty that resolved within one week. In the ilioinguinal cohort, three patients developed temporary groin numbness that resolved within 2–3 weeks, two experienced small hematomas at the needle site resolving in one week, and one reported transient shooting pain in the inguinal region lasting 10 days, attributed to temporary nerve irritation. In the genitofemoral cohort, two patients reported mild erythema at the insertion site resolving within 48 hours, and one experienced brief upper thigh hypersensitivity lasting one week. All complications resolved spontaneously with conservative management, and no major or permanent adverse effects were observed.

4. Discussion

Our study demonstrates that pRFA is an effective therapeutic option for chronic pudendal neuralgia, providing a mean pain relief duration of 9.48 ± 9.52 weeks. This was substantially longer than the relief observed after the first (3.98 ± 3.56 weeks, p < 0.0001) and most recent perineural steroid injections (3.32 ± 3.21 weeks, p < 0.0001). Patients also experienced significant improvements in quality of life at 4 weeks (p = 0.0014), 6 weeks (p = 0.0045), and 3 months (p = 0.0110), with a corresponding reduction in analgesic use, independent of baseline symptom severity or duration.

Building on these findings, we incorporated continuous radiofrequency ablation with CT guidance in the treatment of ilioinguinal and genitofemoral neuropathies. Pain scores decreased significantly from 6.87 ± 1.25 to 1.73 ± 1.28 for ilioinguinal neuropathy (p < 0.0001) and from 6.36 ± 1.34 to 2.36 ± 1.08 for genitofemoral neuropathy (p = 0.0007). Relief was durable, lasting an average of 21.76 ± 19.04 weeks for ilioinguinal and 17.68 ± 12.98 weeks for genitofemoral neuropathy.

Perineural steroid injections and nerve blocks have long been used as first-line therapies for pelvic neuropathy, but their benefits diminish with repeated use and may even worsen long-term outcomes [41]. pRFA has emerged as a durable option, with several studies showing benefit versus steroid injections; direct head-to-head comparisons with cRFA remain limited and heterogeneous [42]. Advances in CT guidance have further improved precision and yielded nearly 100% technical success, reinforcing its utility as a preferred intervention [27].

Our findings build on this evidence by demonstrating the superiority of pRFA over steroid injections in extending pain relief duration. Collard et al. reported that pRFA significantly prolonged pain relief compared to the most recent injection (p = 0.0195) but not the initial one (p = 0.64), while pain scores trended lower but without statistical significance (p = 0.1094 and p = 0.7539) [27]. In a long-term follow-up by Krinjen, 79% of patients described their condition as “much better” at 3 months, with durable improvement maintained across 430 pRFA treatments over four years, yielding an 89% long-term success rate [25]. Similarly, Fang et al. found a 92.1% clinical effective rate at 3 months in patients receiving pRFA plus pudendal nerve block versus 35.9% in those receiving block alone [43]. Taken together, these results reinforce the sustained efficacy of pRFA for pudendal neuralgia and are consistent with our cohort’s outcomes.

Evidence also supports ablation techniques for ilioinguinal and genitofemoral neuropathies. In a randomized trial of 70 patients with post-surgical orchialgia, pulsed RFA produced >50% pain reduction in 80% of patients compared to 23% in the sham group, with 50% discontinuing analgesics versus 3.3% in controls (p = 0.001) [44]. A study of 42 patients with ilioinguinal neuralgia similarly found microwave ablation provided 12.5 months of relief versus only 1.6 months with local infiltration, while a smaller series of 10 patients achieved an 83% success rate and ~70% mean pain reduction [39,45]. Case-based reports also highlight benefit, such as RFN at the L1 origin yielding 4–5 months of relief and individual cases maintaining improvement for at least 3 months [39]. Despite these encouraging results, limitations such as small cohorts, lack of imaging guidance, and short follow-up have restricted generalizability. These gaps are addressed by our study with CT-guided continuous RFA and extended follow-up.

While our study offers important insights, several limitations should be acknowledged. The repeated-measures design without a control group and reliance on subjective, patient-reported outcomes introduce potential bias, particularly in the absence of objective pain assessment tools. The influence of a placebo effect also cannot be excluded. Furthermore, the six-month follow-up period limits conclusions about long-term efficacy and durability. These factors restrict generalizability across broader populations and extended timelines. Future research should adopt larger, multicenter designs incorporating objective outcome measures and longer follow-up to strengthen external validity.

5. Conclusions

In conclusion, our study supports radiofrequency ablation as an effective treatment for pudendal, ilioinguinal, and genitofemoral neuropathic pain. Patients experienced meaningful improvements in pain, quality of life, and reduced analgesic use, with consistent outcomes across symptom severities. By using CT guidance and evaluating multiple nerves, we provide a comprehensive perspective on its role in managing pelvic and groin neuropathies. These findings reinforce radiofrequency ablation as a valuable option, while underscoring the need for larger studies with extended follow-up to confirm long-term efficacy.