.

1. GYNAECOLOGY
The Use of Pulsed Radiofrequency for
the Treatment of Pudendal Neuralgia:
A Case Series
C.E. Frank
Cairina E. Frank, MSc;1,2
Teresa Flaxman, PhD;2,3,4
Yvette Goddard, MD;4,5
Innie Chen, MD, MPH;2,3,4
Cici Zhu, MD;2,3,4
Sukhbir S. Singh, MD2,3,4
1
Department of Medicine, McGill University, Montreal, QC
2
The Ottawa Hospital Research Institute, Ottawa, ON
3
Department of Obstetrics and Gynecology, The Ottawa Hospital, Ottawa, ON
4
Department of Medicine, University of Ottawa, Ottawa, ON
5
Department of Anesthesiology, The Ottawa Hospital, Ottawa, ON
Abstract
Objective: Pudendal neuralgia is a recognized cause of chronic pelvic
pain. The diagnosis is complex, and there is no consensus on ideal
management. Many current methods do not provide adequate relief.
Pulsed radiofrequency is a minimally invasive option that has been
reported for its use in other neuropathies. This study aimed to
evaluate the feasibility and safety of using transvaginal pulsed
radiofrequency for the treatment of pudendal neuralgia and to
generate a hypothesis on its efficacy.
Methods: A retrospective review was conducted of women who were
treated with pulsed radiofrequency for chronic pelvic pain owing to
pudendal neuralgia between January 2012 and December 2017 at
an academic tertiary care centre. (Canadian Task Force
Classification II-3).
Results: A total of seven patients were included. The mean age was
43.7 (standard deviation 7.97). The average number of pulsed
radiofrequency treatments was 4.43 (range 1−12), and the duration
of effect averaged 11.4 weeks (standard deviation 3.09). There
were no major or minor complications at the time of procedure or at
follow-up visits.
Conclusions: Pulsed radiofrequency may be an effective and safe
treatment option for the management of pudendal neuralgia for
women in whom conservative management has not been effective.
Future controlled studies are needed to confirm this hypothesis.
Résumé
Objectif : La nevralgie pudendale est une cause connue de douleurs
pelviennes chroniques. Le diagnostic est complexe, et il n’y a pas de
consensus sur la prise en charge ideale. Beaucoup des methodes
employees actuellement n’offrent pas un soulagement adequat. La
radiofrequence pulsee est une methode a effraction minimale dont
l’utilisation a ete documentee pour traiter d’autres neuropathies. Cette
etude visait a evaluer s’il est faisable et s^ur de traiter la nevralgie
pudendale par radiofrequence pulsee transvaginale, et a emettre une
hypothese sur l’efficacite de cette methode.
Méthodologie : Les auteurs ont etudie retrospectivement les dossiers
de femmes ayant ete traitees par radiofrequence pulsee pour des
douleurs pelviennes chroniques causees par une nevralgie
pudendale entre janvier 2012 et decembre 2017 dans un centre de
soins tertiaire universitaire (classification II-3 du Groupe d’etude
canadien).
Résultats : L’etude a porte sur sept patientes dont l’^age moyen etait de
43,7 ans (ecart-type : 7,97). Le nombre moyen de traitements par
radiofrequence pulsee etait de 4,43 (etendue : 1−12), et l’effet
durait en moyenne 11,4 semaines (ecart-type : 3,09). Il n’y a eu
aucune complication majeure ou mineure au moment de
l’intervention ou du suivi.
Conclusion : La radiofrequence pulsee pourrait ^etre une option
therapeutique efficace et s^ure pour la nevralgie pudendale chez les
femmes chez qui la prise en charge classique n’a pas ete efficace.
Des essais comparatifs seront necessaires pour confirmer cette
hypothese.
© 2019 The Society of Obstetricians and Gynaecologists of Canada/La
Société des obstétriciens et gynécologues du Canada. Published by
Elsevier Inc. All rights reserved.
J Obstet Gynaecol Can 2019;41(11):1558−1563
https://doi.org/10.1016/j.jogc.2019.01.019
INTRODUCTION
P udendal neuralgia (PN) is a recognized cause of
chronic pelvic pain. PN typically manifests as a sharp
Key Words: Pudendal neuralgia, pulsed radiofrequency, chronic
pain, refractory pain
Corresponding author: Dr. Sukhbir S. Singh, Department of
Obstetrics and Gynecology and Department of Anesthesiology, The
Ottawa Hospital, ON. susingh@toh.ca
Competing interests: The authors declare that they have no
competing interests.
Each author has indicated that they meet the journal’s requirements
for authorship.
Received on October 20, 2018
Accepted on January 2, 2019
Available online on March 23, 2019
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2. or burning pain that may progressively worsen throughout
the day or with prolonged sitting.1
Other symptoms
include paresthesia, the sensation of a foreign object in the
patient’s vagina or rectum,2
or severe pain with only minor
stimuli (allodynia).1
Moreover, PN can be implicated in
bowel, bladder, and/or sexual dysfunction and may have a
profound impact on the patient’s quality of life.2,3
The
pudendal nerve arises from sacral nerves S2 to S4; it pro-
vides sensory innervation to the vagina, vulva, and peri-
neum and motor innervation to the perineal muscles.1,2
Nerve injury or entrapment may occur by the following
means: mechanical injury from repetitive muscle spasms or
pressure from surrounding ligaments; direct injury during
surgery, trauma, or childbirth; an infection; or an immuno-
logic process.1, 4
The diagnosis of PN is complex and often results in
patients having to cope with pain for a prolonged period
of time before treatment is initiated. Furthermore, there is
no consensus on the ideal management of PN.2,4
Typically,
early treatment is conservative, with oral analgesics, neuro-
modulators, lifestyle management, and physiotherapy com-
monly used. If the pain continues, patients may be offered
nerve blocks or may undergo decompressive surgery; how-
ever, less than half of these patients report being pain free
after these interventions.1,4,5
Pulsed radiofrequency (PRF) is a minimally invasive option
that has recently been reported in patients with lateral fem-
oral cutaneous neuralgia and ilioinguinal neuralgia.2
It is a
relatively new technique that is quick and has minimal
adverse events, thereby allowing for repeated use in
patients with chronic pain. It acts as a non-destructive tech-
nique compared with the previously used continuous
radiofrequency because it avoids exposure to high temper-
atures.2,3,6
The mechanism of action of PRF in the man-
agement of pain is not yet clear; however, it is thought to
involve neural modulation without alteration of the motor
or sensory nerve fibers.6
Few studies have examined the use of PRF in patients with
PN, and of those studies, only a few have studied its use
transvaginally, which is the method used in the presented
series. This study aimed to evaluate the feasibility and
safety of using transvaginal PRF for the treatment of PN
and to generate a hypothesis on its efficacy.
METHODS
We conducted a retrospective chart review on all women
treated with PRF at an academic tertiary level practice for
chronic pelvic pain attributable to PN between January
2012 and December 2017. Cases were identified through
billing records. A case was included if the woman had been
treated for chronic pelvic pain (lasting more than 6
months) caused by PN refractory to conventional multi-
modal management and had experienced temporary relief
of symptoms after pudendal nerve block(s). Moreover, the
patient had to have been followed up for at least 3 months
after the treatment. All patients were treated with standard
transvaginal PRF (pulsed at 42°C for 90 seconds with a
pulse rate of 2; Baylis Medical, Saint-Laurent, QC). Cases
were treated in a clinic setting with the option of intrave-
nous sedation and/or pre-procedural pudendal nerve
blocks with local anesthetic agents (5−10 mL 1% lidocaine
mixed with 0.25% bupivacaine) administered using a stan-
dard pudendal block kit. After examination, the surgeon
placed a radiofrequency ablation−compatible needle (22
gauge; Diros Technology, Markham, ON) transvaginally
and inserted it 0.5 cm to 1 cm into the sacrospinous liga-
ment (medial to the ischial spine). A 100-mm probe (Baylis
Medical) was then inserted through the needle. A sensory
test was used in some cases to confirm placement followed
by delivery of the pulsed energy. The clinic uses the Brief
Pain Inventory to follow the patient’s pain response in
addition to the history by the medical provider.
A chart review was performed to collect demographic, clin-
ical, and perceived pain information. The outcomes mea-
sured were duration of pain relief as reported by the
patient, complication rate, and success of treatment. Suc-
cess was determined by improvement of pain symptoms
greater than 6 weeks’ duration (longer than the standard
nerve block). Approval for this project was obtained
through The Ottawa Hospital Research Ethics Board (Pro-
tocol ID: 20170592-O1H).
RESULTS
A total of 7 patients treated for PN who had received a PRF
procedure were identified from billing records. Demographic
information is presented in Table 1. The average age was
43.7 (standard deviation [SD] 7.97), and average body mass
index was 27.83 kg/m2
(SD 3.37 kg/m2
). Five patients
(71%) had other diagnosed medical conditions (including
hypothyroidism [2 patients], gastroesophageal reflux disease
[2 patients], asthma [2 patients], and diabetes mellitus
[2 patient]), and three (43%) were also diagnosed with endo-
metriosis. No patients were diagnosed with other chronic
pain disorders. Three patients had undergone laparoscopy
(for diagnosis or excision of endometriosis), and three had a
history of other surgical procedures (cystoscopy, total laparo-
scopic hysterectomy or bilateral salpingo-ophorectomy
and management of cervical dysplasia, total abdominal
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3. hysterectomy or bilateral salpingo-oophorectomy). Four
patients had been pregnant in the past, and two had living
children who were delivered vaginally. Three patients (43%)
still had regular menses with an average duration of 4.5 days,
and the remaining four were amenorrheic for various reasons
(surgical, medical, or menopause).
All seven patients initially presented with dyspareunia, one
experienced dysmenorrhea, three (43%) had dysuria, two
(29%) had dyschezia, and four (57%) had pain aggravated by
sitting. The instigating factor for pain was commonly
unknown (43%); three patients (43%) attributed the pain to
surgery and one to trauma or a fall (14%). Patients described
their pain as “burning, numbing, deep, heavy, sharp, stabbing,
radiating, aching or ripping.” All patients had tenderness over
Table 1. Characteristics of the patient population (n = 7
except where indicated)
Variables
Mean (SD) or
frequency (%)
Demographics
Age 43.7 (7.97)
BMI, kg/m2
27.83 (3.37)
Smoker
Yes 2 (28.57)
No 5 (71.43)
Gynaecological history
Gravida 1.0 (1.15)
Vaginal delivery (n = 4) 4 (100.00)
Other gynaecological diagnosis
None 4 (57.14)
Endometriosis 3 (42.86)
Menstruation
Menses
Yes 3 (42.86)
No 4 (57.14)
Regular (n = 3)
Yes 3 (100.00)
No 0
Heavy (n = 3)
Yes 0
No 3 (100)
Duration, days 4.5 (1.32)
Amenorrhea
Yes 4 (57.14)
No 3 (42.86)
Reason for amenorrhea (n = 4)
Hysterectomy 2 (50.00)
Menopause 1 (25.00)
Medical suppression 1 (25.00)
Pain
Dysmenorrhea (n = 3)
Yes 1 (33.33)
No 2 (66.67)
Dyspareunia
Yes 7 (100.00)
No 0
Dysuria
Yes 3 (42.86)
No 2 (28.57)
Not reported 2 (28.57)
(continued)
Table 1. (Continued)
Variables
Mean (SD) or
frequency (%)
Dyschezia
Yes 2 (28.57)
No 2 (28.57)
Not reported 3 (42.86)
With sitting
Yes 4 (57.14)
No 0
Not reported 3 (42.86)
Instigating factor
Surgery 3 (42.86)
Nothing or unknown 3 (42.86)
Fall 1 (14.29)
Physical examination
Left vulvar allodynia
Yes 3 (42.86)
No 2 (28.57)
Not reported 2 (28.57)
Left ischial spine tenderness
Yes 6 (85.71)
No 0
Right vulvar allodynia
Yes 2 (28.57)
No 2 (28.57)
Not reported 3 (42.86)
Right ischial spine tenderness
Yes 3 (42.86)
No 2 (28.57)
Not reported 2 (28.57)
BMI: body mass index.
GYNAECOLOGY
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4. their ischial spine (five patients had unilateral tenderness,
whereas two had bilateral tenderness), and three also pre-
sented with allodynia (43%). All patients had been referred
to physiotherapists with experience managing chronic pelvic
pain and had trialed numerous medications, including typical
analgesics such as acetaminophen and ibuprofen; in some
cases, further management was required, such as with nar-
cotics, medical cannabis, or neuromodulators.
The average number of PRF treatments per patient was
4.43 (range 1−12) (Tables 2 and 3). The average duration
of pain relief or improvement was 11.4 (SD 3.09; range
3−21) weeks. The duration of effect per patient is pre-
sented in the Figure. There were no major or minor com-
plications at the time of the procedure in any of the
patients, nor were there complications at their follow-up
visits. Patients reported an overall improvement in their
quality of life; some expressed an ability to return to work
or to wear pants or use a bicycle without pain or noted an
enhancement in their overall mood.
Three patients stopped treatment with PRF; one was dis-
charged from the clinic because of resolution of her symp-
toms, whereas the remaining two returned to pudendal nerve
blocks with local anesthetic agents. The first patient returned
for lack of effect from PRF, and the other had improved
sufficiently to require only infrequent management in the
form of nerve blocks. The patients who are still undergoing
treatment are being followed every 4 to 6 months.
DISCUSSION
In this paper, we present a series of patients with PN who
were treated with transvaginal PRF. PN is a complex con-
dition, and its ideal management is still not clear.7
Typically,
early management begins conservatively with education,
physiotherapy, lifestyle modifications, and medical therapy.
If the patient does not improve with conservative meas-
ures, pudendal nerve blocks can be performed through a
transgluteal or transvaginal approach. Studies have shown
efficacy with this method, which has provided pain relief
lasting up to 6 weeks.8
Finally, if symptoms persist, or if
entrapment is questioned, patients may be offered decom-
pression surgery; however, the evidence of its efficacy and
the availability of the procedure are limited.9,10
PRF is a relatively new technique that addresses the short-
comings of the conventional continuous radiofrequency tech-
nique.11
PRF allows for lower temperatures because it uses
high-voltage bursts permitting heat dissipation, thus lowering
the risk of tissue destruction.12
Moreover, it does not cause
damage to the nervous tissue or biochemical alterations (e.g.,
cytokine up-regulation or changes in gene expression).11,12
The mechanism of pain relief is unclear, although it is thought
to be related to altered transmission of pain signals.12
To our knowledge, only a few studies have examined the use
of PRF for PN, consisting of only case reports that followed
a maximum of two patients. Current literature reports symp-
tom relief between 6 weeks and 10 months, with no reported
complications.2−4,11
This study followed a larger sample size
Table 2. Information on pulsed radiofrequency (PRF)
procedures (n = 7)
Variables
Mean (SD) or
frequency (%)
No. of courses 4.43 (3.96)
Overall duration of pain relief
or improvement, weeks
11.4 (3.09)
Complications None
Further PRF courses
Yes 4 (57.14)
No 3 (42.85)
Table 3. Specific pain description and pain relief or improvement after treatment per patient
Patient number Age Description of pain
Number of
PRF courses
Average
duration, weeks
Average pain score
before treatmenta
Average pain score
after treatmenta
1 53 Burning, numbness, spasms 4 8 7.5 2
2 53 Stabbing, sharp, radiating, deep, tingling 1 2.5 7 3
3 39 Chronic 2 12 7 0
4 33 Burning 2 14 7 0
5 36 Heavy, burning, deep, aching, sharp 9 19.3 6 1
6 47 Stabbing, burning, deep, sharp 7 20.7 7 2
7 45 Ripping 2 3 9 3.5
PRF: pulsed radiofrequency.
a
Pain scores displayed are an average of the reported numerical rating scale from the Brief Pain Inventory.
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5. and had patients who underwent multiple treatment sessions.
Similar to previous research, this study found substantial
pain relief ranging from 0−21 weeks in this group of patients
with a mean duration of 11.4 weeks, compared with tradi-
tional nerve blocks, which typically last 6 weeks. Moreover,
patients showed improved quality of life (ability to return to
work, wear pants, sit for longer durations, ride a bicycle).
Despite these encouraging results, one patient did not
respond to this treatment. It is possible she did not have true
PN, the targeted site was not correct, or the treatment was
truly not effective in her case.
Although our study had a larger sample size than in other
publications, as well as numerous PRF treatments, there are
still limitations to address. This study was retrospective, and
thus data were limited to what was available within the medi-
cal records. We also relied on patient reports of pain intensity
and symptom relief that may have been inaccurate; however,
research shows that self-reporting is typically a reliable mea-
sure of pain.13
Moreover, the patients included in this study
did not have to strictly meet the Nantes diagnostic criteria of
PN; however, they did require a response to the pudendal
nerve block, thus allowing for consistency within the study
population. Finally, even though this study is larger than
those reported in prior publications, the sample size is still a
limitation, and the lack of a control group confines the scope
of the methodology.
CONCLUSION
This study demonstrated that transvaginal PRF may be an
effective and safe treatment option for the management of
PN for women in whom conservative management has
not been effective. Future controlled studies are needed to
confirm this hypothesis.
Acknowledgements
The authors would like to thank the nurses and staff at The
Ottawa Hospital Chronic Pain Clinic and the Shirley E.
Greenberg Women’s Health Center for their clinical sup-
port for the patients in this series.
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