The Use of a Collagen Conduit for Transposing an Iatrogenic Saphenous Nerve Neuroma: A Surgical Technique

S ome nerves of the lower extremity are superficial in nature and are susceptible to damage after a traumatic injury or surgical intervention. Peripheral nerve injury can result in neuroma formation, in which the damaged nerve undergoes an inflammatory reaction followed by unorganized regeneration of the distal segment, forming a bulbous ending.1 The milieu of the neuroma increases nerve fiber sensitivity through a decreased threshold for excitability.2 Thus, neuromas can be a significant source of pain and often require multiple therapeutics for symptom management. First-line management of neuromas consists of pharmacological modalities to decrease nerve excitation with other adjunctive treatments added for persistent symptoms. In cases refractory to pharmacologic management, surgical intervention may be required. Common surgical interventions described include targeted muscle reinnervation and regenerative peripheral nerve interfaces. Both of these have been reported on in the literature as successful management techniques for traumatic neuromas. The theory, during surgical management of neuromas, of transferring the proximal nerve segment into an adjacent structure such as muscle or bone is widely supported. This process protects the nerve from mechanical stressors that can trigger neuropathic pain. For some neuromas of the foot and ankle, as will be described in this case, transfer into an adjacent structure is not feasible as there is limited anatomic space and surrounding musculature for adequate burial and nerve immobilization.3 A solution for treating neuromas in areas of limited space is neuroma excision with the placement of the proximal nerve segment into a collagen conduit. This enables the proximal end of the nerve to remain protected and independent of the surrounding anatomy. Gould and colleagues published the largest cohort of foot and ankle neuromas treated with excision and collagen nerve-conduit placement. In a retrospective review of 69 nerveconduit constructs, patients reported significant improvement in 59/69 cases (85%). The nerves involved included the 2,3 intermetatarsal (28), 3,4 intermetatarsal (26), tibial (2), lateral plantar (1), a middle branch of the lateral plantar nerve (1), dorsomedial hallucal (medial branch of the superficial peroneal nerve) (2), lateral hallucal (1), superficial peroneal (1), a calcaneal branch of the tibial (4), deep peroneal (1), common peroneal (1), and sural (1).3 In this report, we use the technique described by Gould and colleagues for the excision and transposition of the saphenous nerve into the periosteum under the protection of a collagen conduit for the treatment of a symptomatic neuroma. To our knowledge, this is the first case describing this technique for the surgical treatment of a distal saphenous nerve neuroma.