Post-traumatic and Post-operative Neuropathy

Dimitris Papadopoulos MD Fellow Of Interventional Pain Practice (FIPP)

Updated 13 February, 2011

GENERAL

Post-traumatic and post-operative neuropathy refers to a neuropathic type of pain occurring after an injury or after a medical intervention, such as surgical operation, injection, radiotherapy etc. The patient usually suffers for a long time from intense pain in the innervation area of the affected peripheral nerve, after having visited doctors of various specialties without any clear diagnosis and proper pharmacotherapy.

DIAGNOSIS

SYMPTOMS

  • Pain is located in the innervation area of the affected nerve possibly radiating to other remote sites that are not related to the affected nerve. Thorough knowledge of anatomy is essential to identify the nerve that has probably been impaired.
  • The pain is of neuropathic type (burning, acute, stabbing pain) and may be accompanied with oversensitivity, numbness, paraesthesia and muscle weakness, according to whether the nerve has motor, sensory or mixed-type innervation.
  • There may be overactivity of the sympathetic system in the area manifested with hyperhidrosia, skin colour changes (blue to red) and temperature changes (from cold to hot).
  • There may be allodynia.
  • Pain and symptoms are usually reproduced with finger pressure on the affected nerve area.


SUPPLEMENTARY EXAMINATIONS

  • Diagnostic block of the peripheral nerve which is suspected to have been affected (estimation is made according to pain distribution). The nerve is blocked by using a neurostimulator and administration of local anaesthetic. In case the patient reports analgesia lasting for as long as the action of the local anaesthetic, then the diagnosis is set for neuropathy of the specific nerve that was blocked.
  • The electromyogram (EMG) can identify the dysfunction of a peripheral nerve and the specific location of the lesion.


TREATMENT

  • Capsaicin dermal patch 8%. This is a new therapy with very good results in the treatment of neuropathic pain due to dysfunction or impairment of peripheral nerves. The patch is applied once and offers analgesia for three months. In case the pain returns after three months, the therapy is repeated again every three months. Capsaicin is not systematically absorbed in the body.
  • Drugs of  the category of antiepileptics, antidepressants, antiarhhythmics and mild opioids
  • Repeated nerve blocks with administration of local anaesthetics and corticosteroids. Neurolysis with alcohol or other neurolytic substance can interrupt the transmission of painful signals, but there is the risk of provoking permanent pain in the anaesthetized area (anesthesia dolorosa). Therefore, it should be avoided.
  • Pulsed Radiofrequency applied on the peripheral nerve or dorsal root ganglion from which the nerve originates. With this technique the nerve is not ablated but it is neuromodulated, and painful signals are either reduced or eliminated. The method can be repeated.
  • Surgical treatment with nerve dissection and debridement of the lesion area.

COMMON CASES OF POST-TRAUMATIC AND POST-OPERATIVE NEUROPATHY

BRACHIAL PLEXITIS

The brachial plexus may be injured following a surgical tumor excision from the axillary area, as happens in breast cancer. Also, irradiation of the operated area after the surgery may cause brachial plexitis.
Abrupt traction of the upper limb after an accident may cause injury of the brachial plexus roots and serious neuropathic pain.
Wrong positioning of lower limbs on the surgical bed with extreme shoulder adduction or prolonged pressure of the plexus by some object may also cause neuropathy.

INTERCOSTOBRACHIAL NEURALGIA

The intercostobrachial nerve may get injured during surgical excision of lymphnodes from the axillary area, in breast cancer.

This nerve is formed by the spinal roots of the 1st and 2nd thoracic nerves. Symptoms extend to the innervation area of these nerves, medial side of the upper arm from the axilla to the elbow and around the upper chest at T1 and T2 dermotomes. Interventional treatments that can be applied are the following:

  • Block of the 1st and 2nd intercostal nerves under fluoroscopic guidance
  • Local subcutaneous infiltration with local anaesthetic and cortisone from the medial side of the upper arm to the axilla

INTERCOSTAL NEUROPATHY AFTER THORACOTOMY

Intercostal nerve injury due to rib traction or nerve dissection may cause intense neuropathic pain in the innervation area of the intercostal nerves that have been injured. The pain begins from the posterior side of the chest and extends to the anterior side of the chest up to the sternum. The dissected nerves in the postoperative scar area may form a  neuroma and cause allodynia along the scar.

Conservative treatment

  • Drugs of  the category of antiepileptics, antidepressants, antiarhhythmics and mild opioids

Interventional therapies that can be applied

  • Intercostal nerve block under fluoroscopic guidance
  • Local subcutaneous infiltration along the incision with local anaesthetic and cortisone

In case the pain is resistant to all therapies, peripheral stimulation is applied with successful results.

NEUROPATHY OF THE 11TH AND 12TH INTERCOSTAL NERVES AFTER NEPHRECTOMY

Intercostal nerve injury due to rib traction or  nerve dissection may cause intense neuropathic pain in the innervation area of the intercostal nerves that have been injured. The pain begins from the posterior side of the chest and extends to the anterior side of the chest to the sternum. The dissected nerves in the postoperative scar area may form neuroma and cause allodynia along the scar.

Conservative treatment

  • Drugs of  the category of antiepileptics, antidepressants, antiarhhythmics and mild opioids

Interventional therapies that can be applied

  • Intercostal nerve block under fluoroscopic guidance
  • Local subcutaneous infiltration along the incision with local anaesthetic and cortisone

In case the pain is resistant to all therapies, peripheral stimulation is applied with successful results.

SCIATIC NEURALGIA

The sciatic nerve may be impaired due to prolonged pressure exerted on the gluteal area by a hard object. This may be caused due to wrong positioning and body weight distribution of the patient on the surgical bed during anaethesia  (general or local).
The sciatic nerve may also be injured when the gluteal area has been struck by a sharp object or when the sciatic nerve has been traumatically dissected.
In the first case, the neurologic lesion is of axonal type and  there is a chance for slow restoration of the nerve function, because the epineurium (nerve’s envelope) is still preserved.

In the second case of neurotmesis, there is need for surgical repair of the nerve’s continuity.

In both cases, there may be permanent neuropathic pain despite the therapeutic treatment. In cases of resistant sciatica, spinal cord stimulation is applied.

NEUROPATHY AFTER LOWER ABDOMEN SURGERY

Surgery for inguinal hernia, varicocele and appendicectomy, may often lead to injury of the iliohypogastric, ilioinguinal and  genitofemoral nerves by surgical instruments or by wrong surgical suturing of the nerves. The result is neuropathic pain in the groin possibly radiating to the genitalia.

Therapeutic options

  • Repeated nerve blocks with administration of local anaesthetics and corticosteroids. Neurolysis with alcohol or other neurolytic substance can interrupt the transmission of painful signals, but there is the risk of provoking permanent pain in the anaesthetized area (anesthesia dolorosa). Therefore, it should be avoided.
  • Drugs of  the category of antiepileptics, antidepressants, antiarhhythmics and mild opioids
  • Pulsed Radiofrequency applied on the peripheral nerve or dorsal root ganglion from which the nerve originates. With this technique the nerve is not ablated but it is neuromodulated and painful signals are either reduced or eliminated. The method can be repeated.
  • Surgical treatment with nerve dissection and debridement of the lesion area.

NEUROPATHY AFTER KNEE ARTHROSCOPY

When introducing the trocar cannulas into the knee joint, there may be provoked injury of the patellar nerves located in the medial and lateral side of the knee under the patella.

The patient may feel strong postoperative neuropathic pain around the knee and may have difficulty in walking and extending the knee. The pain may be radiating to the posterior side of the knee. There may be overactivity of the sympathetic nervous system in the area (changes in skin colour and temperature) and allodynia. The whole condition is wrongly characterized by orthopaedicians as “complex regional pain syndrome” (CRPS) or “reflex sympathetic dystrophy” (RSD).

Treatment

  • Drugs of  the category of antiepileptics, antidepressants, antiarhhythmics and mild opioids
  • Femoral nerve block sessions with administration of local anaesthetics
  • Infiltration of the postoperative scar at the trocar entry site with local anaesthetic and cortisone
  • Intra-articular application of pulsed radiofrequency to the infrapatellar area

MEDICAL INFORMATION SOURCES

1. PAIN PRACTICE JOURNAL

2. BONICA”S MANAGEMENT OF PAIN

3. PAIN PHYSICIAN JOURNAL

4. INTERVENTIONAL PAIN MANAGEMENT BOOK

5. NEUROMODULATION JOURNAL