The efficacy of sensory nerve coaptation in DIEP flap breast reconstruction - Preliminary results of a double-blind randomized controlled trial.

BACKGROUND: Sensory nerve coaptation has great potential to restore sensation after autologous breast reconstruction. However, blinded and randomized studies are lacking. We therefore present the preliminary results of our ongoing double-blinded randomized controlled trial that compares sensory recovery of innervated versus non-innervated DIEP flaps. METHODS: Patients who underwent DIEP flap breast reconstruction between July 2019 and February 2022 were included and randomized. The anterior cutaneous branch of the second or third intercostal nerve was coapted. Pre- and postoperative sensory testing was performed with Semmes-Weinstein Monofilaments, Pressure Specified Sensory Device, and a thermostimulator, for tactile and temperature thresholds. RESULTS: This interim analysis comprised 41 patients contributing 29 innervated and 38 non-innervated breasts. At 24 months of follow-up, the mean monofilament value of the flap skin was lower in innervated than in non-innervated flaps (4.48 vs. 5.20, p = 0.003). Touch thresholds were lower the center of the innervated flaps (47.8 vs. 71.2 g/mm2, p = 0.036), and heat pain was more often imperceptible in non-innervated flaps (42.1% vs. 10.3%, p = 0.004). No adverse events were associated with sensory nerve coaptation. CONCLUSIONS: These preliminary results indicate superior sensibility and recovery of protective sensation in innervated compared with non-innervated DIEP flaps. Although the results of the completed trial must be awaited to establish the full clinical impact, including highly anticipated quality of life outcomes, we encourage continuation of scientific and clinical efforts in this promising technique.

Sensory recovery and the role of innervated flaps in autologous breast reconstruction-a narrative review.

Background and Objective: Continuing (micro)surgical developments result in satisfactory aesthetic outcomes after autologous breast reconstruction. However, sensation recovers poorly and remains a source of dissatisfaction and potential harm. Sensory nerve coaptation is a promising technique to improve sensation in the reconstructed breast. Methods: In this literature review an overview of current knowledge about sensory recovery in autologous breast reconstruction and the role of innervated flaps is presented. A thorough PubMed search was conducted, using the terms "autologous breast reconstruction", "innervated" and "sensation". Key Content and Findings: The breast skin is predominantly innervated by the second until sixth intercostal nerve. Some nerves can occasionally be spared during mastectomy, especially during nipple-sparing mastectomy, but transection of sensory nerves is inevitable and leads to impaired sensation. Besides unpleasant, this is unanticipated by patients and negatively influences quality of life. Coaptation between the third anterior intercostal nerve and a sensory nerve from the donor site improves sensory recovery. The donor site and nerve vary, depending on the flap type chosen. The sensory nerves from the commonly used abdominal DIEP flap originate from the 7th until 12th thoracic spinal nerves. Non-abdominal flaps, including the back, buttocks, or thigh area, can also be accompanied with a sensory nerve. Nerve coaptation can be performed directly, or by using grafts or conduits to obtain tensionless repair if necessary. It can be utilized in both immediate as well as delayed autologous breast reconstruction. No adverse outcomes of nerve coaptation have been described. And, most importantly: improved sensory recovery improves patient satisfaction and quality of life. Conclusions: Restoring sensation is, besides restoring aesthetic appearance, an important goal in breast reconstruction. Current evidence unambiguously demonstrates superiority of innervated flaps compared to non-innervated flaps. Sensory recovery initiates earlier and it approaches normal sensation more closely in innervated flaps, without associated risks or extensive increase in operating time. This improves patient satisfaction and quality of life. It is, therefore, a valuable addition to autologous breast reconstruction. These findings encourage implementation of sensory nerve coaptation in standard clinical care.

Rat donor lung quality deteriorates more after fast than slow brain death induction.

Donor brain death (BD) is initiated by an increase in intracranial pressure (ICP), which subsequently damages the donor lung. In this study, we investigated whether the speed of ICP increase affects quality of donor lungs, in a rat model for fast versus slow BD induction. Rats were assigned to 3 groups: 1) control, 2) fast BD induction (ICP increase over 1 min) or 3) slow BD induction (ICP increase over 30 min). BD was induced by epidural inflation of a balloon catheter. Brain-dead rats were sacrificed after 0.5 hours, 1 hour, 2 hours and 4 hours to study time-dependent changes. Hemodynamic stability, histological lung injury and inflammatory status were investigated. We found that fast BD induction compromised hemodynamic stability of rats more than slow BD induction, reflected by higher mean arterial pressures during the BD induction period and an increased need for hemodynamic support during the BD stabilization phase. Furthermore, fast BD induction increased histological lung injury scores and gene expression levels of TNF-α and MCP-1 at 0.5 hours after induction. Yet after donor stabilization, inflammatory status was comparable between the two BD models. This study demonstrates fast BD induction deteriorates quality of donor lungs more on a histological level than slow BD induction.