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Dellon. Plast Aesthet Res 2022;9:45 https://dx.doi.org/10.20517/2347-9264.2022.13 Page 5 of 15

The reason there has been reported so much lack of sensitivity and specificity of the Tinel sign is that the
presence of a positive Tinel sign varies according to the degree of compression, that is, the underlying
pathophysiology present at the time of testing. Early in nerve compression, there is just endoneurial edema,
and there may be no symptoms or just paresthesias, but once demyelination begins, the Tinel sign appears,
and once an advanced axonal loss occurs, the Tinel sign can disappear [53-55] . The presence of a positive Tinel
[56]
sign can also vary depending upon how hard the nerve is palpated and the experience of the examiner .
Therefore, over the past more than 40 years, if I can elicit a Tinel sign at a known site of anatomic
narrowing, I am confident that there is a chronic nerve compression present. In the lower extremity, the
presence of a positive Tinel sign over the tibial nerve in the tarsal tunnel has proven to have at least an 80%
positive predictive value for good to excellent results from lower extremity peripheral nerve compression
from the now “classic” Dellon Triple nerve decompression (neurolysis of the common peroneal nerve at the
knee, the deep peroneal nerve at the foot dorsum, the release of the tarsal tunnel with its included neurolysis
of the medial, lateral and calcaneal nerves) [41,57,58] .

THE IDEAL SURGICAL CANDIDATE
An ideal patient is a person with diabetes who has symptoms of numbness and tingling with or without
pain. The person who has just pain, without numbness, may not be an ideal candidate as that patient might
have small fiber neuropathy. Small fiber neuropathy is rare but can be identified by a skin biopsy that
quantitates unmyelinated nerve fibers in the dermis of the leg and thigh in the presence of normal tests for
large fiber function. The skin biopsy will likely be positive in patients with the commonest form of diabetic
neuropathy (a mixed large and small fiber neuropathy), and also in patients with an advanced form of
chronic nerve compression without diabetes. In chronic nerve compression, both large, myelinated fibers
[59]
and small, unmyelinated fibers can undergo degeneration . What must be present in the ideal candidate
for surgery are large fiber symptoms, such as tingling and numbness, and some measurement of large fiber
function that is abnormal, such as vibratory perception threshold (quantitative vibrometry), or touch
perception threshold (Pressure-Specified Sensory Device or Semmes-Weinstein monofilaments), or
tm
abnormal static or moving two-point discrimination [60-63] . An abnormal electrodiagnostic test that shows
nerve compression is also a form of large fiber evaluation.

The ideal candidate for decompression should have had an extensive medical trial of neuropathic pain
medications, such as Neurontin, Gabapentin, Duloxetine, Elavil, or a combination of these drugs, and found
that they had too many side effects or else were ineffective.

The ideal candidate for decompression, in addition to having the correct diagnosis, must have good
circulation in the lower extremities. This can be determined by palpating the pulse, and if this examination
is not clearly in favor of good arterial inflow, then Doppler flow studies, ankle/brachial index, and, if
needed, cutaneous oxygen levels can be ascertained. The surgical incisions clearly may not heal in the
absence of sufficient circulation. The same can be said for pedal edema. In the presence of cardiac or renal
problems, edema is present, which is a contra-indication to surgery.

In addition to the positive Tinel sign of the tibial nerve, as discussed above, a good prognosis can be
[64]
expected if the patient has had previously successful carpal tunnel surgery . From a database of 300
patients who had a Dellon Approach to their lower extremity nerve compressions, 35 patients were found
who had previous carpal tunnel release. The presence of a good response to median nerve decompression at
the wrist gave an 88% positive predictive value to response to the decompression of the tibial and peroneal
nerves.