Beware the painful nerve palsy; neurostenalgia, a diagnosis not to be missed
Strat Traum Limb Recon
Beware the painful nerve palsy; neurostenalgia, a diagnosis not to be missed
Jane Halliday 0 1
Tim Hems 0 1
Hamish Simpson 0 1
0 T. Hems Department of Trauma and Orthopaedics, Glasgow Royal Infirmary , 84 Glasgow St, Glasgow G4 0SF , UK
1 J. Halliday (&) H. Simpson Department of Trauma and Orthopaedics, Edinburgh Royal Infirmary , 51 Little France Crescent, Old Dalkeith Road, Edinburgh EH16 4SA , UK
We present a case of painful radial nerve palsy following application of a humeral lengthening frame. At re-operation, the radial nerve was found to be compressed against a distal pin. This was re-sited providing immediate pain relief and a gradual resolution of the radial nerve palsy. Pain in association with a nerve palsy should alert the clinician to the possibility of nerve compression that may benefit from urgent decompression.
Neurostenalgia; Limb lengthening; Decompression; Radial nerve
Introduction
Neuropathic pain, arising from a lesion of the nervous
system, is defined as persistent intractable pain
disproportional between the extent of the lesion and the severity of
the pain. It is associated with sensory and/or motor
disturbance [
1
]. Neurostenalgia is a neuropathic pain that
results from continuing irritation of an anatomically intact
nerve by a noxious agent [
1
]. It may be chronic or acute
and is not associated with excess sudomotor or vasomotor
activity. Common causes include compression, distortion,
ischaemia or tethering of the nerve. Removal of the
causative agent typically results in immediate relief of pain and
A 10-year-old girl underwent application of a humeral
lengthening frame of her right humerus to correct severe
humeral shortening gradually. The shortening was
secondary to osteomyelitis of the right proximal humerus aged
10 weeks. This had left her with a 10-cm discrepancy
between the lengths of the right and left humeri, resulting in
significant functional difficulties. The lengthening frame
was applied with the elbow extended without any
intraoperative complications. In recovery, her right hand was
warm and well perfused with full sensation and movement
of the wrist and small hand joints. On the first post-operative
day, however, she complained of severe burning pain in her
right arm and hand requiring significant opiates for relief
and a pain team review. Examination revealed evidence of a
partial right radial nerve palsy; weakness of right wrist
extension, an inability to extend the fingers and diminished
sensation on the dorsum of the first webspace. She
displayed evidence of hyperalgesia with an exaggerated
response to pin-prick on the dorsum of the first webspace.
There was no mechanical allodynia. All other hand and
wrist movements and sensation were intact.
An ultrasound scan of the right arm was performed. This
revealed no haematoma or collection. The radial nerve was
not visualised.
On the second post-operative day, her symptoms
decreased slightly. However, on the third post-operative
day, her symptoms did not settle further and the patient was
taken back to theatre for exploration of the radial nerve due
to ongoing severe pain. The radial nerve was found to be in
continuity without any bruising or contusion. Distally, it
was found to pass tightly against the most distal external
fixator pin such that, with the elbow flexed the nerve
became tightly pressed against the pin. The distal pin was
removed and re-sited slightly proximal.
Post-operatively, there was complete resolution of the
right arm pain and hyperalgesia. Sensation to the first
webspace recovered on the second post-operative day with
motor function returning more gradually. There was full
recovery of radial nerve motor function at 4 months
postoperatively.
Discussion
In 1943, Seddon [
2
] introduced a classification of nerve
injuries based on three main types of nerve fibre injury and
whether there was continuity of the nerve: neurotmesis,
axonotmesis and neurapraxia [
2
]. Neurotmesis is the most
severe injury. It is a lesion in which the axon and its
encapsulating connective tissue lose their continuity,
resulting in Wallarian degeneration. Axonotmesis is also a
degenerative lesion in which the relative continuity of an
axon and its myelin sheath is lost, with preservation of its
connective tissue framework. Neurapraxia is a
nondegenerative lesion in which there is a local conduction
block, typically of large myelinated fibres. Anatomical
continuity is preserved with selective demyelination.
Neurology may deteriorate as a result of progressive
damage to the nerve. Neurapraxia commonly results from
compression and/or ischaemia of peripheral nerves.
Recovery occurs by Schwann cell repair, which occurs
over weeks to months [
1
].
Neurapraxia can occur with or without pain. Normal
sensory function is the product of an actively maintained
equilibrium between neurons and their environment [
3
].
Any disruption of this equilibrium that results from
changes in sensitiv (...truncated)