bobber -

In light of an August, 2009 article from the Journal of Neurosurgery, for which I only have an impressive abstract, and assuming that the not insubstantial cost is somehow covered by insurance, you might very well want to get an MR Neurography, in case there is any ambiguity as to what's going in down there:

J Neurosurg. 2009 Aug 7. [Epub ahead of print]

Magnetic resonance neurography for the evaluation of peripheral nerve, brachial plexus, and nerve root disorders.

Du R, Auguste KI, Chin CT, Engstrom JW, Weinstein PR.

Department of Neurological Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachussetts; and the Departments of. [sic]

Object Treatment of spinal and peripheral nerve lesions relies on localization of the pathology by the use of neurological examination, spinal MR imaging and electromyography (EMG)/nerve conduction studies (NCSs). Magnetic resonance neurography (MRN) is a novel imaging technique recently developed for direct imaging of spinal and peripheral nerves. In this study, the authors analyzed the role of MRN in the evaluation of spinal and peripheral nerve lesions. Methods Imaging studies, medical records, and EMG/NCS results were analyzed retrospectively in a consecutive series of 191 patients who underwent MRN for spinal and peripheral nerve disorders at the University of California, San Francisco between March 1999 and February 2005. Ninety-one (47.6%) of these patients also underwent EMG/NCS studies. Results In those who underwent both MRN and EMG/NCS, MRN provided the same or additional diagnostic information 32 and 45% of patients, respectively. Magnetic resonance neurograms were obtained at a median of 12 months after the onset of symptoms. The utility of MRN correlated with the interval between the onset of symptoms to MRN. Twelve patients underwent repeated MRN for serial evaluation. The decrease in abnormal signal detected on subsequent MRN correlated with time from onset of symptoms and the time interval between MRN, but not with resolution of symptoms. Twenty-one patients underwent MRN postoperatively to assess persistent, recurrent, or new symptoms; of these 3 (14.3%) required a subsequent surgery. Conclusions Magnetic resonance neurography is a valuable adjunct to conventional MR imaging and EMG/NCS in the evaluation and localization of nerve root, brachial plexus, and peripheral nerve lesions. The authors found that MRN is indicated in patients: 1) in whom EMG and traditional MR imaging are inconclusive; 2) who present with brachial plexopathy who have previously received radiation therapy to the brachial plexus region; 3) who present with brachial plexopathy and have systemic tumors; and 4) in patients under consideration for surgery for peripheral nerve lesions or after trauma. Magnetic resonance neurography is limited by the size of the nerve trunk imaged and the timing of the study.

PMID: 19663545 [PubMed - as supplied by publisher]

http://www.ncbi.nlm.nih.gov/pubmed/1...ubmed_RVDocSum

While you're at it, you might also want to check out "The value of MR neurography for evaluating extraspinal neuropathic leg pain: a pictorial essay," Moore KR, Tsuruda JS, Dailey AT, AJNR Am J Neuroradiology, 2001 Apr;22(4):786-94, free full text at http://www.ajnr.org/cgi/reprint/22/4/786.pdf

Department of Radiology, Section of Neuroradiology, University of Utah School of Medicine, Salt Lake City 84132, USA.

SUMMARY: Fifteen patients with neuropathic leg pain referable to the lumbosacral plexus or sciatic nerve underwent high-resolution MR neurography. Thirteen of the patients also underwent routine MR imaging of the lumbar segments of the spinal cord before undergoing MR neurography. Using phased-array surface coils, we performed MR neurography with T1-weighted spin-echo and fat-saturated T2-weighted fast spin-echo or fast spin-echo inversion recovery sequences, which included coronal, oblique sagittal, and/or axial views. The lumbosacral plexus and/or sciatic nerve were identified using anatomic location, fascicular morphology, and signal intensity as discriminatory criteria. None of the routine MR imaging studies of the lumbar segments of the spinal cord established the cause of the reported symptoms. Conversely, MR neurography showed a causal abnormality accounting for the clinical findings in all 15 cases. Detected anatomic abnormalities included fibrous entrapment, muscular entrapment, vascular compression, posttraumatic injury, ischemic neuropathy, neoplastic infiltration, granulomatous infiltration, neural sheath tumor, postradiation scar tissue, and hypertrophic neuropathy.

PMID: 11290501 [PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov/pubmed/1...ubmed_RVDocSum

Simply put, MR Neurography appears to be gaining traction that it didn't have a few years ago, subject to at least one unique technological issue in the interpretation of the scans. "Magic angle effects in MR neurography," Chappell KE, Robson MD, Stonebridge-Foster A, Glover A, Allsop JM, Williams AD, Herlihy AH, Moss J, Gishen P, Bydder GM, AJNR Am J Neuroradiology 2004 Mar;25(3):431-40, free full text at http://www.ajnr.org/cgi/reprint/25/3/431.pdf

Comment in:
AJNR Am J Neuroradiol. 2004 Mar;25(3):352-4.

Department of Imaging, Hammersmith Hospital NHS Trust, London, England, UK.

BACKGROUND AND PURPOSE: Magic angle effects are well recognized in MR imaging of tendons and ligaments, but have received virtually no attention in MR neurography. We investigated the hypothesis that signal intensity from peripheral nerves is increased when the nerve's orientation to the constant magnetic induction field (B(0)) approaches 55 degrees (the magic angle). METHODS: Ten volunteers were examined with their peripheral nerves at different orientations to B(0) to detect any changes in signal intensity and provide data to estimate T2. Two patients with rheumatoid arthritis also had their median nerves examined at 0 degrees and 55 degrees. RESULTS: When examined with a short TI inversion-recovery sequence with different TEs, the median nerve showed a 46-175% increase in signal intensity between 0 degrees and 55 degrees and an increase in mean T2 from 47.2 to 65.8 msec. When examined in 5 degrees to 10 degrees increments from 0 degrees to 90 degrees, the median nerve signal intensity changed in a manner consistent with the magic angle effect. No significant change was observed in skeletal muscle. Ulnar and sciatic nerves also showed changes in signal intensity depending on their orientation to B(0). Components of the brachial plexus were orientated at about 55 degrees to B(0) and showed a higher signal intensity than that of nerves in the upper arm that were nearly parallel to B(0). A reduction in the change in signal intensity in the median nerve with orientation was observed in the two patients with rheumatoid arthritis. CONCLUSION: Signal intensity of peripheral nerves changes with orientation to B(0). This is probably the result of the magic angle effect from the highly ordered, linearly orientated collagen within them. Differences in signal intensity with orientation may simulate disease and be a source of diagnostic confusion.

PMID: 15037469 [PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov/pubmed/1...ubmed_RVDocSum

Finally, there remains the possibilty that if this imaging technology really is as good as it has been claimed (and operated by people who are equally aware of its foibles and limitations) it may indeed become possible to successfully resolve nerve entrapments through surgery, through the insertion of something more pliable that an external boot, but from what I can tell, neurosurgeons are still stuggling with the problem in the presumeably more straitforward situation of treating carpal tunnel syndrome, and although I did see a reference in an abstract to the use of so-called "fat pads," I have no idea whether that's in lieu of the standard cast, which I doubt. (And treatment oucomes for carpal tunnel syndrome appeared to predominate running a PubMed search under "nerve entrapment surgery scarring.")

For what it's worth.

Mike