Active Nerve Management for Below-knee Amputation: A Comparison of Approaches.

Area of Science:

• Surgical techniques
• Amputation surgery
• Nerve regeneration

Background:

• Targeted muscle reinnervation (TMR) and regenerative peripheral nerve interface (RPNI) are crucial for managing postamputation pain and neuroma.
• These nerve management techniques can be applied during below-knee amputation (BKA) using either a posterior approach (PA) or a through-the-wound approach (TTWA).

Purpose of the Study:

• To compare the operative time, RPNI utilization, and postoperative outcomes between the PA and TTWA for active nerve management during BKA.
• To inform surgical decision-making for below-knee amputation procedures.

Main Methods:

• Retrospective review of 36 patients undergoing active nerve management at the time of BKA (February 2019 - May 2023).
• Patients were divided into PA (n=16) and TTWA (n=20) cohorts.
• Comparison of operative time, TMR and RPNI rates, wound dehiscence, infection, and prosthetic clearance time.

Main Results:

• The PA group had a significantly longer operative time (251 min) compared to the TTWA group (208 min) (P=0.03).
• All patients received TMR; however, RPNI was used in 95% of TTWA patients versus 56% of PA patients (P=0.01).
• Wound dehiscence was more frequent in the TTWA cohort (40%) compared to the PA cohort (25%) (P=0.01). No significant differences in infection or prosthetic clearance time were observed.

Conclusions:

• The PA approach, while more time-consuming, offers more direct access to recipient nerves, potentially reducing the need for RPNI.
• The TTWA approach is quicker but associated with a higher risk of postoperative wound dehiscence.
• Surgeons should weigh the trade-offs between operative time, RPNI utilization, and wound complications when selecting an approach for active nerve management during BKA.