The current landscape of sensory neurotization in implant breast reconstruction

Following nipple-sparing mastectomy (NSM), breast and nipple-areola complex (NAC) sensation is often decreased, with up to 73% of NAC sensation may be lost (1). As sensory loss is highly variable, factors such as increased age, prior breast revisional surgeries, and prior radiotherapy may contribute to a decrease in postoperative sensation (2,3). Recently, advances in mastectomy techniques have sparked significant interest in sensory preservation and reconstruction to improve patients’ quality of life. Preliminary results of NAC neurotization and implant-based breast reconstruction (IBR) have gained traction across scientific literature and social media. Before widespread adoption of sensate IBR may be advocated, it is critical to assess the quality of existing data.

Sensate IBR was first described in 2019 by Peled and Peled where the authors simultaneously performed NAC neurotization with a NSM and prepectoral direct-to-implant reconstruction (4). Patients successfully demonstrated preservation of 2-point NAC discrimination in 87% of cases over 3 months. Since then, the group published an updated study incorporating standardized pressure-specified sensory device (PSSD) measurements in a cohort of 79 breasts (5). They found 66% of patients to have excellent sensibility within the first 6 months postoperatively, with an additional 7% by 12 months.

Despite these promising findings, only three experimental studies have followed Peled and Peled’s initial pilot study—none with robust negative controls. In 2020, Djohan et al. reported on a cohort of five breasts who underwent sensate IBR and found improved sensory recovery in all breast regions at 10.59 months (6). In 2024, Chang et al. published their technique for breast neurotization where three out of 56 patients underwent sensate IBR following NSM, with contralateral normal breasts as controls (7). They found similar sensation between neurotized breasts and controls after 12 months, although the overall cohort consisted of both autologous reconstruction and non-NSM.

Despite the existing data, results are preliminary, as the majority is compared to prior literature rather than large control groups (8). Measurement techniques differed among these studies, as Chang et al. used Semmes-Weinstein monofilaments while Peled et al. and Djohan et al. used PSSDs (5-7). Moreover, there is no standard neurotization technique in IBR. Peled et al. and Djohan et al. used nerve allografts for coaptation following preservation of the fourth intercostal nerves, while Chang et al. proposed using the fourth intercostal nerve as a nerve autograft for the preserved lateral cutaneous nerves (5-7). Unlike autologous grafting, acellular nerve grafting has been shown to undergo a slower regeneration process as allografts depend on proliferating Schwann cells to undergo neovascularization from the recipient bed unlike autografts (9). The time as to when this occurs is dependent on allograft length, as lengths over 6 cm have been associated with decreased functional recovery (9). The variability in graft type between studies raises the question of how much of postoperative sensory recovery is due to axonal regeneration, which should occur around 2–3 months at the earliest assuming a growth rate of 1 mm/day, rather than by spontaneous nerve recovery (4,5,9). In studies assessing spontaneous nerve recovery, non-reinnervated autologous free flaps were found to have satisfactory sensory recovery at 6 and 12 months postoperatively (10). In both Peled et al.’s and Djohan et al.’s studies, follow-up times were also long, specifically between 4 and 12 months (5,6). Thus, understanding whether reinnervation presents a clinical advantage at earlier time points would be important for the future of neurotization in IBR. Finally, implant placement varied among the studies. Peled et al. placed implants in the prepectoral plane, while Djohan et al. and Chang et al. opted for a subpectoral placement, which may influence sensory recovery provided there is no direct contact between nerve allograft and implant (5-7).

With the increasing influence of social media on plastic surgery, patients are increasingly more likely to inquire about postoperative breast sensation and opportunities to mitigate sensory loss. With the advent of the BREAST-Q questionnaire, research has shown that sensory recovery of the NAC greatly improves patient satisfaction, with nipple sensation, position, projection, scarring, and symmetry being most important to patients (11). These positive results from nipple-specific BREAST-Q questionnaires may lead to inevitable tension between medical professionals and patients with respect to medical safety and patient quality of life. At times, the opportunity to conduct a “nerve preserving oncologic mastectomy” may be unavailable as oncologic technique must take precedence over sensory outcomes. As such, a strong collaboration between the reconstructive and breast surgeon is vital to the success of sensate IBR.

Despite minimal risks, medical professionals should advise patients on rare potential complications, including postmastectomy pain syndrome that may arise from intercostal neuromas (4). Transected or injured nerves during the neurotization process may lead to further diminished sensation or chronic neuropathic pain. To date, there has not been an accepted technique for sensate breast reconstruction as the breast has multiple nerves responsible for overall sensation. Surgical technique for neurotization has varied as some studies have opted for direct coaptation between subareolar nerves and the preserved lateral intercostals, while others have implemented nerve allografts. The optimal length of allografts, however, remains understudied. Zhang et al. recently developed an equation to predict total nerve length required; they found on average, 6.9 cm of nerve allograft was required for sensory improvement, however, did not have a comparison control group (12).

Limited literature in this field may be due to a combination of inadequate institutional resources and challenges in nerve identification during mastectomy. As nerve allografting is not yet available worldwide, the potential impact of infection, added operative time, and cost-benefit analyses has not been fully elucidated. Furthermore, use of additional sensory measurement tools such as dermatomal sensory-evoked potentials as seen in other neurotization studies, would be useful in assessing sensory recovery pertaining to the entire sensory nerve pathway up to the somatosensory cortex (13). Therefore, caution should be taken to avoid premature adoption of these techniques as data are currently limited and inconclusive. Further research with larger sample sizes, additional follow-up time points, standardized techniques, and patient-reported outcomes are needed to safely advocate for sensate IBR.

Acknowledgments

None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Annals of Breast Surgery. The article has undergone external peer review.

Peer Review File: Available at https://abs.amegroups.com/article/view/10.21037/abs-25-7/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://abs.amegroups.com/article/view/10.21037/abs-25-7/coif). P.W.H. serves as an unpaid editorial board member of Annals of Breast Surgery from May 2021 to December 2026. The other authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Dossett LA, Lowe J, Sun W, et al. Prospective evaluation of skin and nipple-areola sensation and patient satisfaction after nipple-sparing mastectomy. J Surg Oncol 2016;114:11-6. [Crossref] [PubMed]
2. Rodriguez-Unda NA, Bello RJ, Clarke-Pearson EM, et al. Nipple-Sparing Mastectomy Improves Long-Term Nipple But Not Skin Sensation After Breast Reconstruction: Quantification of Long-Term Sensation in Nipple Sparing Versus Non-nipple Sparing Mastectomy. Ann Plast Surg 2017;78:697-703. [Crossref] [PubMed]
3. Lai HW, Chang YL, Chandrachamnong K, et al. Factors associated with alteration of nipple or skin sensation and impact of duration of time following nipple-sparing mastectomy (NSM): an analysis of 460 cases with comparison of conventional versus endoscopic- or robotic-assisted NSM. World J Surg Oncol 2023;21:222. [Crossref] [PubMed]
4. Peled AW, Peled ZM. Nerve Preservation and Allografting for Sensory Innervation Following Immediate Implant Breast Reconstruction. Plast Reconstr Surg Glob Open 2019;7:e2332. [Crossref] [PubMed]
5. Peled AW, von Eyben R, Peled ZM. Sensory Outcomes after Neurotization in Nipple-sparing Mastectomy and Implant-based Breast Reconstruction. Plast Reconstr Surg Glob Open 2023;11:e5437. [Crossref] [PubMed]
6. Djohan R, Scomacao I, Knackstedt R, et al. Neurotization of the Nipple-Areola Complex during Implant-Based Reconstruction: Evaluation of Early Sensation Recovery. Plast Reconstr Surg 2020;146:250-4. [Crossref] [PubMed]
7. Chang TN, Lu JC, Sung CW, et al. Elongation of intercostal nerve cutaneous branches for breast and nipple neurotization during breast reconstruction after mastectomy for breast cancer: case-control study. Br J Surg 2024;111:znae005. [Crossref] [PubMed]
8. Bijkerk E, van Kuijk SMJ, Beugels J, et al. Breast sensibility after mastectomy and implant-based breast reconstruction. Breast Cancer Res Treat 2019;175:369-78. [Crossref] [PubMed]
9. Saheb-Al-Zamani M, Yan Y, Farber SJ, et al. Limited regeneration in long acellular nerve allografts is associated with increased Schwann cell senescence. Exp Neurol 2013;247:165-77. [Crossref] [PubMed]
10. Santanelli F, Longo B, Angelini M, et al. Prospective computerized analyses of sensibility in breast reconstruction with non-reinnervated DIEP flap. Plast Reconstr Surg 2011;127:1790-5. [Crossref] [PubMed]
11. Peled AW, Amara D, Piper ML, et al. Development and Validation of a Nipple-Specific Scale for the BREAST-Q to Assess Patient-Reported Outcomes following Nipple-Sparing Mastectomy. Plast Reconstr Surg 2019;143:1010-7. [Crossref] [PubMed]
12. Zhang C, Moroni EA, Moreira AA. One Size Does Not Fit All: Prediction of Nerve Length in Implant-based Nipple-Areola Complex Neurotization. J Reconstr Microsurg 2024; Epub ahead of print. [Crossref] [PubMed]
13. Santanelli F, Tenna S, Pace A, et al. Free flap reconstruction of the sole of the foot with or without sensory nerve coaptation. Plast Reconstr Surg 2002;109:2314-22; discussion 2323-4. [Crossref] [PubMed]