Review Question - QID 218839

This patient sustained a traumatic partial small finger amputation at the proximal interphalangeal joint level. Avulsion-type injuries have been shown to pose the most significant risk of digital neuroma formation compared to other mechanisms of injury.

Finger injuries can incur significant long-term disability for patients. Partial finger amputations often necessitate revision amputation in order to provide appropriate soft tissue coverage over exposed bone. Emphasis should be placed on maintaining as much finger length as possible to ensure maximal functional outcomes. Traction neurotmesis is often performed for exposed digital nerves as an attempt to mitigate subsequent neuroma formation. The risk for symptomatic neuroma formation is low (reported <10%), however index finger revision amputations and avulsion-type mechanisms of injury have been shown to incur the highest risk for symptomatic neuroma formation. Patients should be made aware of this potential complication and be provided regular follow-up appointments to monitor their outcomes.

Vlot and colleagues performed a retrospective review to determine risk factors of neuroma formation after traumatic revision amputation procedures performed within their hospital system. They found that 6.6% of patients developed a symptomatic neuroma at a mean time of 6.4 months post-injury. After multivariable regression analysis, they discovered that index finger injuries and avulsion injury mechanisms were associated with a significantly higher risk for symptomatic neuroma formation. They conclude that surgeons should be aware of these high-risk patients and counsel them for this potential long-term complication.

Van der Avoort and colleagues similarly performed a retrospective review of traumatic finger injuries and risk for neuroma formation. They included both patients with traumatic amputations and patients without amputations who required digital nerve repair. They found a very low (1%) risk for neuroma formation in non-amputation injuries with digital nerve repair, however, a high risk (7.8%) in traumatic partial amputation injuries requiring revision amputation. They conclude that patients with amputation finger injuries have a significantly greater risk of developing a symptomatic neuroma compared to non-traumatic injuries treated with primary neurorrhaphy.

Figure A shows this patient’s traumatic injury with avulsion-based partial amputation of the small finger. Figure B shows the 6-month follow-up clinical photos with appropriate wound healing.

Incorrect Answers:
Answer 2: Single-digit involvement has a pragmatically lower risk for symptomatic neuroma compared to multiple digits.
Answer 3: The level of revision amputation at the proximal phalanx compared to a more distal amputation does not impose a higher risk of a symptomatic neuroma.
Answer 4: Performing revision amputation in the ED compared to the operative theatre does not have an effect on outcomes.
Answer 5: The index finger is known to be at higher risk for symptomatic neuroma formation due to the higher density of nerve fibers compared to other digits.