Diagnosis and treatment of pudendal nerve entrapment syndrome subtypes: imaging, injections, and minimal access surgery

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>To improve diagnostic accuracy and achieve high levels of treatment success in patients with pudendal nerve entrapment (PNE) syndromes, the author of this study applied advanced technology diagnostics in distinguishing the various syndrome types according to the different entrapment locations and evaluated new minimal access surgical techniques to treat each subtype.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>Two hundred cases were prospectively evaluated using a standardized set of patient-completed functional and symptom assessments, a collection of new physical examination maneuvers, MR neurography, open MR image–guided injections, intraoperative neurophysiology, minimal access surgery, and formal outcome assessment with the Oswestry Disability Index, pain diagrams, and analog pain scales.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>Four primary types of PNE syndromes were identified based on the different locations of entrapment: Type I, entrapment at the exit of the greater sciatic notch in concert with piriformis muscle spasm; Type II, entrapment at the level of the ischial spine, sacrotuberous ligament, and lesser sciatic notch entrance; Type III, entrapment in association with obturator internus muscle spasm at the entrance of the Alcock canal; and Type IV, distal entrapment of terminal branches. The application of new, targeted minimal access surgical techniques led to sustained good to excellent outcomes (50–100% improvement in the pain score or functional score) in 87% of patients. Most of these patients obtained most of their improvement within 4 weeks of surgery, although some continued to experience progressive improvements up to 12 months after surgery.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>The application of advanced diagnostics to categorize PNE syndrome origins into 4 major subtypes and the subsequent treatment of each subtype with a tailored strategy greatly improved therapeutic outcomes as compared with those reported when only a single treatment paradigm was applied to all patients.</jats:p></jats:sec>

3-Tesla High-Field Magnetic Resonance Neurography for Guiding Nerve Blocks and Its Role in Pain Management

“…35 Diagnostic pudendal nerve blocks represent a means of functional testing that is best interpreted in concert with history, skilled physical examination, and diagnostic MR neurography findings. 9,34 The pudendal nerve may be entrapped at various locations, extending from the infrapiriformis foramen to the distal pudendal canal. 9 The pudendal nerve may be blocked proximally to the entrapment site 9,36-39 ; however, selective pudendal nerve blocks may not be possible in the infrapiriformis foramen and upper subgluteal space, because of the proximity of the posterior femoral cutaneous nerve, which shares sensory perineal innervation.…”

“…9,34 The pudendal nerve may be entrapped at various locations, extending from the infrapiriformis foramen to the distal pudendal canal. 9 The pudendal nerve may be blocked proximally to the entrapment site 9,36-39 ; however, selective pudendal nerve blocks may not be possible in the infrapiriformis foramen and upper subgluteal space, because of the proximity of the posterior femoral cutaneous nerve, which shares sensory perineal innervation. A pudendal perineural injection at these locations is prone to false-positive testing because of an uncontrollable spread of the local anesthetic to the posterior femoral cutaneous nerve.…”

“…Wide-bore magnet designs can offer similarly sufficient patient access than dedicated open MR imaging systems. 5,9,18 If the isocenter of the bore can be reached, table movement can be minimized and needle maneuvering can be performed while the patient is in the bore of the magnet. 5,6,15 The static magnetic field, radiofrequency pulses, and the gradient magnetic field contribute to special conditions of an interventional MR imaging environment.…”

“…Perineurally delivered corticosteroids may result in an interruption of inflammatory pathways on a cellular level and sustained pain relief. [9][10][11] MR neurography guidance is especially suited for deeply situated and small targets and for injectants that require accurate drug delivery, such as Botulinum neurotoxin. 1,12 Interventional MR neurography rivals computed tomography because it provides superior contrast resolution and avoids potentially harmful ionizing radiation exposure.…”

Correlation between Anatomical Segments of the Pudendal Nerve and Clinical Findings of the Patient with Pudendal Neuralgia

“…Based on anatomical classifications [3][4][5][6][7]16], pudendal neuralgia can cause a wide variety of symptoms, ranging from S3 radiculopathy to small fiber neuropathy with simultaneous symptoms affecting the clitoris, perineum, vulva, vagina, and/or rectum. Knowledge of PN anatomy can help to understand painful syndromes of the perineum.…”