Evaluating the discordant relationship between Tarlov cysts and symptoms of pudendal neuralgia.

BACKGROUND: Pudendal neuralgia is a painful neuropathic condition involving the pudendal nerve dermatome. Tarlov cysts have been reported in the literature as another potential cause of chronic lumbosacral and pelvic pain. Notably, they are often located in the distribution of the pudendal nerve origin at the S2, S3, and S4 sacral nerve roots and it has been postulated that they may cause similar symptoms to pudendal neuralgia. Literature has been inconsistent on the clinical relevance of the cysts and if they are responsible for symptoms. OBJECTIVE: To evaluate the prevalence of S2-S4 Tarlov cysts at the pudendal nerve origin (S2-S4 sacral nerve roots) in patients specifically diagnosed with pudendal neuralgia, and establish association of patient symptoms with location of Tarlov cyst. STUDY DESIGN: A retrospective study was performed on 242 patients with pudendal neuralgia referred for pelvic magnetic resonance imaging from January 2010 to November 2012. Dedicated magnetic resonance imaging review evaluated for presence, level, site, and size of Tarlov cysts. Among those with demonstrable cysts, subsequent imaging data were collected and correlated with the patients' clinical site of symptoms. Statistical analysis was performed using χ2, Pearson χ2, and Fisher exact tests to assess significance. RESULTS: Thirty-nine (16.1%) patients demonstrated at least 1 sacral Tarlov cyst; and of the 38 patients with complete pain records, 31 (81.6%) had a mismatch in findings. A total of 50 Tarlov cysts were identified in the entire patient cohort. The majority of the Tarlov cysts were found at the S2-S3 level (32/50; 64%). Seventeen patients (44.7%) revealed unilateral discordant findings: unilateral symptoms on the opposite side as the Tarlov cyst. In addition, 14 (36.8%) patients were detected with bilateral discordant findings: 11 (28.9%) had bilateral symptoms with a unilateral Tarlov cyst, and 3 (7.9%) had unilateral symptoms with bilateral cysts. Concordant findings were only demonstrated in 7 patients (18.4%). No significant association was found between cyst size and pain laterality (P = .161), cyst volume and pain location (P = .546), or cyst size and unilateral vs bilateral pain (P = .997). CONCLUSION: The increased prevalence of Tarlov cysts is likely not the etiology of pudendal neuralgia, yet both could be due to similar pathogenesis from part of a focal or generalized condition.

Repeated Ganglion Impar Block in a Cohort of 83 Patients with Chronic Pelvic and Perineal Pain.

BACKGROUND: The ganglion impar is the first pelvic ganglion of the efferent sympathetic trunk that relays pelvic and perineal nociceptive messages and therefore constitutes a therapeutic target. OBJECTIVE: The objective of this single-center study was to evaluate the effectiveness of 3 repeated ganglion impar blocks in patients with chronic pelvic and perineal pain on intention-to-treat. STUDY DESIGN: Retrospective single-center study. SETTING: We reviewed the medical records of 83 patients with chronic refractory pelvic and perineal pain. On intention-to-treat analysis, 62 (74.7%) of the patients received 3 ganglion impar blocks. METHODS: Ganglion impar block was performed with 0.75% ropivacaine via a lateral approach over the Co1-Co2 coccygeal joint with computed tomography (CT) guidance. The effectiveness of ganglion impar blocks was evaluated by visual analogue scale (VAS) before and 30 minutes after the blocks. Evaluation at least one month after the block was also performed by Patient Global Impression of Change (PGI-C). RESULTS: A total of 220 blocks were performed, 193 (87.7%) of which were considered to be positive with immediate but transient improvement of pain by more than 50% and complete but transient pain relief after the procedure in 119 (54.1%) procedures. The variation of the VAS score before and after each block was statistically significant (P < 0.001). Similarly, the VAS score before repeated blocks was significantly improved with decreased pain intensity over time (P = 0.001). Analysis of the PGI-C one month after the block demonstrated improvement in 41% of cases in the overall population and in 43.6% of cases in the subgroup of 62 patients treated by 3 blocks. LIMITATIONS: Retrospective study, short term follow-up. CONCLUSIONS: Repeated ganglion impar blocks allowed short-term reduction of pain intensity with a moderate intermediate-term effect. Ganglion impar appears to be a useful therapeutic target to block the nociceptive message by acting on sensitization phenomena.Key words: Pudendal neuralgia, impar block, pain, perineal, coccygodynia.

[Magnetic resonance neurography for the identification of pudendal neuralgia]. / Neurografía por resonancia magnética para la identificación de la neuralgia del nervio pudendo.

The pudendal nerve entrapment is an entity understudied by diagnosis imaging. Various causes are recognized in relation to difficult labors, rectal, perineal, urological and gynecological surgery, pelvic trauma fracture, bones tumors and compression by tumors or pelvic pseudotumors. Pudendal neuropathy should be clinically suspected, and confirmed by different methods such as electrofisiological testing: evoked potentials, terminal motor latency test and electromyogram, neuronal block and magnetic resonance imaging. The radiologist should be acquainted with the complex anatomy of the pelvic floor, particularly on the path of pudendal nerve studied by magnetic resonance imaging. High resolution magnetic resonance neurography should be used as a complementary diagnostic study along with clinical and electrophysiological examinations in patients with suspected pudendal nerve neuralgia.

Neurografía por resonancia magnética para la identificación de la neuralgia del nervio pudendo / Magnetic resonance neurography for the identification of pudendal neuralgia

La neuralgia del nervio pudendo (NP) es una entidad poco estudiada por imágenes. Se reconocen varias causas, tales como compresión a través de su paso por estructuras ligamentarias; estiramiento por partos laboriosos; lesiones secundarias a cirugías rectales, perineales, urológicas y ginecológicas, traumatismos con o sin fractura de huesos pelvianos; procesos inflamatorios/autoinmunes; tumores del NP, y, compresión/desplazamiento por tumores o seudotumores de pelvis. El diagnóstico de neuralgia del NP se sospecha por la clínica y se confirma por diferentes métodos, tales como las pruebas electrofisiolológicas: potenciales evocados, test de latencia motora terminal y electromiograma, y, a través de bloqueos neurales y resonancia magnética. La neurografía por resonancia magnética de alta resolución, debería ser empleada como estudio diagnóstico complementario junto a la clínica y exámenes electrofisiológicos, en los pacientes con sospecha de neuralgia del NP.

The pudendal nerve entrapment is an entity understudied by diagnosis imaging. Various causes are recognized in relation to difficult labors, rectal, perineal, urological and gynecological surgery, pelvic trauma fracture, bones tumors and compression by tumors or pelvic pseudotumors. Pudendal neuropathy should be clinically suspected, and confirmed by different methods such as electrofisiological testing: evoked potentials, terminal motor latency test and electromyogram, neuronal block and magnetic resonance imaging. The radiologist should be acquainted with the complex anatomy of the pelvic floor, particularly on the path of pudendal nerve studied by magnetic resonance imaging. High resolution magnetic resonance neurography should be used as a complementary diagnostic study along with clinical and electrophysiological examinations in patients with suspected pudendal nerve neuralgia.

CT-guided percutaneous pulse-dose radiofrequency for pudendal neuralgia.

PURPOSE: The purpose of our study was to evaluate the efficacy of computed tomography (CT)-guided percutaneous pulse-dose radiofrequency (PDRF) for the treatment of chronic pain in patients with pudendal neuralgia (PN) unresponsive to conservative approaches. METHODS: From March 2010 to January 2012, 30 patients with a diagnosis of PN were prospectively enrolled in the study, 18 women and 12 men (mean age 47 years). A 20-gauge cannula with a 10-cm length was placed under CT guide in the pudendal (Alcock's) canal. After the spindle was removed, a radiofrequency needle with a 5-mm active tip was introduced. The appropriate needle placement near the pudendal nerve, without an involvement of the vessels, was confirmed with an injection of 1-2 ml of contrast agent. PDRF was performed with 1,200 pulses at high voltage (45 V) with 20 ms duration followed by 480 ms silent phases. RESULTS: Twenty-six patients completed the study. Procedural success was achieved in all patients. Mean VAS scores before PDRF was 9 ± 0.7. Patients had a great improvement in pain intensity after 1 week by PDRF (mean VAS scores 3.8 ± 1.7, p < 0.05), with a stabilization of the symptomatology in the following months (mean VAS scores 1.5 ± 1.1 at 6 months by PDRF, p < 0.05) and excellent results after 1 year by the procedure (mean VAS scores 1.9 ± 0.7, p < 0.05). CONCLUSIONS: In our preliminary experience, CT-guided percutaneous PDRF should be recommended for treatment of PN because we evaluated the tolerability of this procedure with satisfactory and encouraging results.