OverviewOktober 1, 2024
Vulvodynia is a chronic pain syndrome affecting respectively the vulva and occurs without an identifiable cause or visible pathology. The pain is usually characterized as a burning, stinging, irritation or sharp pain that occurs in the vulva, including the labia. It may be constant, intermittent or happening only when the vulva or the vagina is touched or while sitting, but is usually defined as lasting for years. The incidence of vulvodynia is not known but it is clearly more common than is generally thought and induces a dys- or even an apareunia in about 15% of women. Vulvodynia is still a serious medical problem as well for the patients as for gynecologists. This pain condition is confusing because pains are located in genital areas, while dermatologic and gynecologic examinations are normal. Treatments are very often limited to the avoidance of vulvar irritants, diet, use of oral and topical medicines, vulvar injections, and surgery. Although vulvodynia was described in the literature in the late 1800s, many questions about its epidemiology and risk factors remain. There has been a tremendous effort to diagnose and treat vulvodynia over the last 15 years, but there is a need for comprehensive information on vulvare pain and on pathologies of the pelvic nerves as potential etiology.
The term vulvodynia is reserved for those patients suffering from such chronic pain that occur in the absence of physical findings. Conditions of infectious, inflammatory, neoplastic, and immunologic origin, as well as evidence for any systemic illness, physical trauma to the vulva, dermatologic conditions, and urinary tract syndromes should be ruled out prior to making such a diagnosis. The diagnosis is then based on the typical complaints of the patients, normal gynecological and dermatological findings, and the absence of identifiable causes. History has to focus on all symptoms such as allodynia, numbness, hypersensitivity, electric shock or stabbing pain, knife-like or aching pain, feeling of a lump or foreign body, twisting or pinching, abnormal temperature sensations, constipation, pain and straining with bowel movements, straining or burning when urinating, painful intercourse, and sexual dysfunction, including hyperarousal and hyposensitivity. An accurate diagnosis requires a comprehensive history focusing on genital and extragenital (lumbosacral areas) symptoms as well as on information’s about previous surgical/obstetrical procedures and pelvic pathologies. Also information’s on possible pathologies of the CNS (spinal cord lesions, multiple sclerosis, Lyme disease…), and dysfunctions of the peripheral nervous system such as motor deficits of hip adduction (L3/Obturator Nerve), knee extensors (L1-L4/Femoral Nerve), ankle dorsiflexion (foot drop – L5) and ankle plantar flexion (S1) are of major importance. Sphincters dysfunctions, motor/sensitive urinary urgency or voiding difficulties are explored by urodynamic testing.
Clinical examination focuses on inspection of the genital organs, supported by a vaginal culture, an urinanalysis, a control of vaginal pH, Pap smear, biopsy of abnormal vulvar areas and a psychosocial assessment. Neurologic examination should include exploration of all lumbosacral nerves with vaginal/rectal palpation of the pudendal nerves and the sacral nerves roots S3-5: apparition of a exquisite tenderness and a Tinel´s sign (sensation of tingling or "pins and needles" in the distribution of the damages nerve) when digital pressure is applied over a pelvic nerve, and improvement in pain when a selective block of the nerve is used, confirm unequivocally the diagnosis.
There are numerous possible causes for vulvodynia, but the most frequent ones are of dermatologic origin. In postmenopausal women, atrophic vaginitis can also cause burning pain. Yeast and lichen simplex chronicus typically produce itching, although sometimes they can present with irritation and pain, so they must be considered in the differential diagnosis. Lichen sclerosus manifests as white epithelium that has a crinkling, shiny, or waxy texture. It can produce pain, especially dyspareunia. The pain is caused by erosions that arise from fragility and introital narrowing and inelasticity. Vulvovaginal lichen planus is usually erosive and preferentially affects mucous membranes, especially the vestibule; it sometimes affects the vagina and mouth, as well.
In regard to infection, Candida albicans and bacterial vaginosis are usually the first conditions that are considered, but they are not common causes of vulvar pain and are never causes of chronic vulvar pain. Very rarely they may cause recurrent pain that clears, at least briefly, with treatment. Herpes simplex virus is very frequently evocated as a potential cause for vulvodynia, but is usually a cause of recurrent but not chronic pain. Chronic pain is more likely to be caused by skin disease than by infection. Lichen simplex chronicus causes itching; any pain is due to erosions from scratching. Skin diseases that affect the vulva are usually pruritic - pain is a later sign. Lichen simplex chronicus (also known as eczema) is pruritus caused by any irritant; any pain that arises is produced by visible excoriations from scratching. It is always important to consider cancer when a patient has an abnormal vulvar appearance and pain that has persisted despite treatment.
Diabetic neuropathy, and post-herpetic neuralgia are possible neurologic causes of vulvar pain reported in the literature. Some of the possible causes are then an inflammatory or autoimmune illness or frequent infections. Multiple sclerosis can also produce such pain. An involvement of the nervous system in any form is supported by the fact that women suffering from vulvo-vaginodynia often report a history of headache, irritable bowel syndrome, interstitial cystitis, fibromyalgia, chronic fatigue syndrome, back pain, and temporomandibular joint disorder. Several studies have noted an increase in anxiety, stress, and depression among women who have vulvodynia. These comorbidities are particularly helpful in establishing the diagnosis of a neurological etiology.
In absence of spinal cord pathologies, vulvodynies correspond to pathologies of the genitofemoral nerve and/or of the pudendal nerve and/or of the sacral nerves roots, “midlle vagidonydies” to pathologies of the pelvic floor and “high vaginodynies” to pathologies of the hypogastric nerves and plexuses
There are vulvodynias mostly located in the dorsal portion of the vulva and are often secondary to obstetrical or proctological procedures with damages of the middle or the dorsal branch of the pudendal nerve. A superficial vulvar trigger point is found while palpation of the pelvic nerves is normal. Pelvic organs dysfunctions are lacking. Improvement in pain by lidocaine infiltration of the trigger point confirms the diagnosis and treatment consist then in same local infiltrations with botulinum toxine A.
When the genitofemoral nerve is affected, pain may be felt in the inguinal area with irradiation in the internal aspect of the thigh and in the genital area. Distal lesions of the genital branch of the genitofemoral nerve induce a anterior vulvodynia. Since the genitofemoral nerve is only sensitive, symptoms are restricted to sensory changes except in male in who loss of cremastic reflex can be observed. Surgical access to the inguinal region (appendectomy, herniorraphia, introduction of lateral trocar for laparoscopy…) exposes patients to risk for such groin pain that has proven to be an extremely difficult problem to treat. Nerve blockade with anesthetic agent or botulinum toxine A is the method of choice as well for diagnosis as for treatment especially. However in failure of medical treatments, several conservative (neurolysis, removal of the mesh) and ablative (neurectomy) procedures doe exist. The current most propagated technique is the triple neurectomy developed by Amid that consist in a neurectomy to all three inguinal nerves (the ilioinguinal, iliohypogastric and the genitofemoral nerve) with a insertion of the proximal cut ends of the nerves under the internal oblique muscle fibers. However, taking into consideration the underlying cause, location, and type of pain, attempts at conservative procedure should almost always be considered before moving to destructive procedures. Therefore, the fist treatment to be considered is the laparoscopic decompression of the genitofemoral nerve by starting the dissection of the nerve at the level of the psoas maucle – in normal anatomical conditions – and to release the nerve by following it trough the scare tissue. Laparoscopic nerve decompression
In case of failure the nerve release procedure, the second option may be the neuromodulation that is an important part of the continuum of managing chronic intractable pain. Several techniques of electrodes implantation has been described ranged from the epidural implantation, the subcutaneous implantation, and the direct implantation of an electrode to the endopelvic portion of the nerves by laparoscopic approach.
Pudendal neuralgia is reserved for women with neuropathic pain in the entire nerve distribution - vulvar, perineal and perianal area – with typically worsening by sitting, relieved by standing, and absent when recumbent or when on a toilet seat. Various further symptoms such as urinary hesitancy, frequency, urgency, constipation/painful bowel movements, reduced awareness of defecation, sexual dysfunction including loss of libido can be observed.
There are numerous possible causes for PN. Some of them are an inflammatory or autoimmune illness, frequent infections. After iatrogenic nerve damages, which are frequent in obstetrics and gynecology, PN is common, with etiologies such as compression of the nerve through a postpartal haematoma, fibrosis of the ischiorectal fossa, stretching of the nerve during delivery or surgical damages during transvaginal sacrospinous colpopexy. More recent interventions using mesh material for sacrospinal fixation, sacro-colpopexy or rectopexy may also expose patients to risk for pudendal nerves damages.
Neurological examination is extremely important for diagnosis. Extrinsic lesions do not include pudendal numbness or troubles of micturition or continence, but imply hyperesthesia. In neurogenic nerve damages, numbness is usually combined with anal deviation (perineal/perianal myoatrophia), normal micturition or eventually bladder overactivity; urinary incontinence occurs only in bilateral lesions.
For diagnosis, the more commonly used tests are the PN motor latency test (PNMLT), electromyography (EMG), diagnostic nerve blocks, and magnetic resonance neurography (MRN). EMG studies of the pudendal nerve, often touted as a diagnostic tool, are unreliable since they can be abnormal after vaginal delivery or vaginal hysterectomy and do not define the neurologic level of the pathology. Transvaginal/transrectal palpation and blockade of the pudendal nerve is the key of the diagnosis.
There are many treatment options depending on the cause of the PN. Reduction or stopping association of medical pain treatment may be the first step in recovery urinary functions, since most pain killers present side effects on bladder and sphincters control.
Because excessive tension (spasm) in the striated muscles of the pelvic floor appears to be common to most of the pelvic pain syndromes, treatment options include always pelvic floor physical therapy to relax pelvic floor muscles and pain medications. Trial of pudendal nerve blocks with botulinum toxine A is a real option, but bilateral infiltration must be done carefully to avoid urinary or fecal incontinence.
Where medical treatments are not successful, surgical treatment is the only etiologic that may be tried. Surgery is then designed to decompress the pudendal nerve at the Alcock’s canal by transgluteal or perineal. In case of pudendal neuralgy secondary to prolapse surgery – especially with mesh implants, including TVT and TOT procedures – but also endometrioses and all further pelvic sidewall surgeries, the laparoscopic approach is indicated for nerves procedures. Laparoscopic decompression of the pudendal nerve
In case of neurogenic lesion of the pudendal nerve (axonal destruction), it is well accepted that the actual state of the art neurosurgical treatment of such neurogenic pain situations is the neuromodulation. Because sacral nerve stimulation does not permit neuromodulation of all pudendal afferent fibres together, it has not been considered to be a real therapeutic option for PN in the international medical literature. Spinelli has reported about the technique of implantation of a tined lead near the nerve by perineal or posterior approach; this technique exposes the patients for risk for lead migration, dislocation or even cable breakage. The laparoscopic technique of implantation called “LION procedure”, enable a safe and reproducible implantation of an electrode array in direct contact to the PN within the protection of the pelvis. LION procedure to the pudendal nerve
The diagnosis of PN is often overdiagnosed: “pudendal neuralgia” with pain irradiation in the buttock or the legs is not a PN, but a sacral radiculopathy. The semeiology is very subtle combining pelvic pain, dys/apareunia, troubles/loss of vesical and/or rectal sensation, pudendal pain (S2-4), vulvo-vaginodynia and coccygodynia (S3-4), sciatica (L5-S2 with “non-pelvic symptoms” such as low-back-pain (lumbosacral trunk, L5), pain and/or abnormal sensations in the legs or in the buttom.
Surgical damages, endometriosis and compression of the sacral nerve roots (SNR) - sacral compartment syndrome - are the most frequent etiologies for SR.
In SR secondary to surgical interventions, damages of the nerves are manifold, and most are due to lack in knowledge on pelvic neuroanatomy but also to mistakes of the surgical technique: section of the nerves, ligature entrapment, traction and clamping injury, suction by continuous blood aspiration near the nerves, compression, contusion, pressure, ischemia by excessive dissection, cutting and electrical or thermal injury. Such intraoperative nerves damages happening are responsible for neuropathic pain with neurologic troubles starting quite immediately after the procedure. In contrast, nerves entrapment by postoperative fibrosis or pelvic varicosis veins compression requires months or years to develop.
In all nerve damages secondary to pelvic procedures, the laparoscopic exploration of the injured nerves for possible decompression must be then indicated as soon as possible, before nerve damages become irreversible and process of chronification and memorization of pain begin.
In endometriosis of the SNR, pains are cyclical, progressive over the time and triggered by the menstruation. In massive involvement, troubles of locomotion and pelvic organs dysfunctions may occur. Laparoscopic exploration enables as well the confirmation of the diagnosis as an adapted treatment based on the decompression of the nerves and resection of endometriosis. Laparoscopic surgery for treatment infiltrating endometriosis of the pelvic somatic nerves 1 Laparoscopic surgery for treatment infiltrating endometriosis of the pelvic somatic nerves2
SR by “pelvic compartment syndrome” must also be considered as a potential etiology. The pain is increased by all situations that increase pelvic venous pressure (prolonged standing and sitting position…), or by any marked pulsation of the pelvic veins (tricuspid insufficient, close anatomic relationship with arteries…). Because pelvic and lower limb veins are similarly in constitution, patients with varicose in the legs should present a higher risk for pelvic varicose veins. Also pelvic interventions and pelvic vein thrombosis may promote changes in pelvic veins circulation. In “vascular entrapment”, the treatment of choice consist in the laparoscopic decompression of the entrapped nerves. Laparoscopic decompression by vascular entrapment
Further rare diagnosis such as sacral tumors or pelvic nerves tumors can also be evocated as potential etiologies. Laparoscopy enables also in these indications an etiologic diagnosis and treatment by decompression of the SNR.
Osteochondrosaroma of the sacra-iliac bone
Vulvodynia are not life-threatening complains that affect million of women over the world. Such pain has a huge impact on a woman´s life, and because the diagnosis is often omitted, many women may remain isolated by a condition that is not easy to discuss. Treatment for vulvodynia may be adapted to a possible etiology, even when medical pain treatments are then still the most frequent used in daily medical practice. Unfortunately, pathologies of the pelvic nerves as potential etiologies are widely omitted. The aim of this manuscript is to draw the attention of physicians and gynecologists on the neurologic aspects of such a gynecologic pain situation. For a proper neuropelveological diagnosis, all information obtained by a detailed history, in combination with both gynecological and neurological assessment are essential. While the genitofemoral and pudendal nerves are accessible for local treatments such as infiltrations, laparoscopic exploration with nerve exploration/decompression has to be considered as the step of choice, since it may result not only in a proper etiological diagnosis but also in a successfully minimal invasive neurosurgical treatment.
