Notes on Violet's Phone Conversation with Dr. Andrew Elkwood

Dr. Elkwood's concern is that physicians may take an approach that is too compartmentalized when diagnosing the cause of pelvic pain, rather than considering all of the possible causes.  Pudendal neuralgia may be just one of the factors contributing to the patient's pain.

Differential Diagnosis 

Process used to make a differential diagnosis may include the following (not necessarily in this order):

  1. MRN  (often sends patients to Dr. Hollis Potter)
  2. Imaging of lumbar spine (most middle aged and older patients will show some pathology that may or may not be related to their pain).  To determine whether the patient has spinal radiculopathy vs. peripheral nerve entrapment or peripheral nerve pathology, the patient is sent to neurosurgery for MRI of Lumbar spine and EMG.
  3. May do an SI joint injection if SI joint dysfunction is suspected
  4. CT with Valsalva maneuver to rule out hernia
  5. CT guided nerve blocks (series of 3)

Surgical Approach 

Dr. Elkwood uses a surgical approach that is appropriate to the patient’s needs.  He believes in a minimally invasive approach if possible.

  1. Most often uses the transischiorectal fossa approach -- can access as high up as the piriformis muscle via this approach using special instruments.  Believes in the importance of sparing other nerves that may be encountered during surgery and feels this approach is best for that. The incision for men and women is 2 fingers lateral to the anus with a vertical perineal incision.
  2. Occasionally uses transgluteal approach but prefers not to go that route unless necessary due to more difficult recovery for the patient after incision through a major muscle.
  3. Anterior approach if needed.

Double Crush Phenomenon

Considering the nerve to be one cell; the nerve may swell proximally as well as distally.  If only the distal portion is treated, pathology may remain and continue to cause pain.  (Sewer pipe analogy – pipe may be clogged out at the street but may also be clogged at the kitchen drain.   If the clog at the street is removed but the clog at the kitchen drain is not removed the sink backup may continue.)  

Intraoperative EMG

During surgery, free-running intraoperative EMG is used, in particular for motor nerves.  This allows for mapping and to confirm that the proper nerve is isolated.  The amperage of the current needed to elicit a response in the muscle is measured prior to release of the nerve and post release of the nerve.  There can be a significant difference in the amount of amperage needed to stimulate the nerve prior to release as opposed to post-release of the nerve.   If a patient has a significant improvement in that measurement, it can indicate a more favorable outcome.

Ligament Sparing

Sacrotuberous ligament spared if possible but if the pudendal nerve is entrapped in that ligament it may be severed.