Neuromas are considered “tumors” of neural structures. For purposes of this chapter, we refer to non-neoplastic neuromas. Neuromas typically form following surgical transection, trauma, or entrapment. Neuromas are considered to be discrete enlargements. If superficial, they may be palpable. If deeper, they may be visualized with noninvasive imaging tools (MRI, ultrasound).
Like trigger points, a neuroma can be stimulated with normal palpation (allodynia). Painful stimuli over a neuroma may lead to an excessive or prolonged pain response, ie, hyperalgesia and hyperpathia. Due to dysfunction of this neural tissue, there may be impairment in conduction. Motor function and sensory processing may be dysfunctional. Autonomous and maladaptive reflexes may be present.
Infiltration with a local anesthetic and steroid may be therapeutic. Perineural infiltration is preferred, since intraneural injections may lead to permanent nerve damage and paradoxically, a deafferentation pain syndrome.
Neuroma injections (NIs) are commonly used as a treatment option in patients with acute and chronic pain. Pain can be present at rest or with movement. Neuroma pain may be exacerbated with constriction, eg, stump and the Morton neuromas.
Trigger points are commonly present in patients who have undergone surgery. This is especially true when the surgical scar injured a peripheral nerve, eg, limb amputation or rib resection or retraction.
Neuromas may be found in the surgical bed:
• In areas exposed to repetitive trauma
• Or, in areas exposed to overuse
Neuromas may be confused with tender points, as is usually found in patients with fibromyalgia. Unlike fibromyalgia, neuromas are typically isolated and develop secondary to a specific event.
Physical examination findings include:
• A palpable and tender swelling that is painful with light touch (allodynia).