Next Article in Journal
The Role of Key Amino Acids of the Human Fe(II)/2OG-Dependent Dioxygenase ALKBH3 in Structural Dynamics and Repair Activity toward Methylated DNA
Previous Article in Journal
Extracellular Vesicles as Biomarkers for Parkinson’s Disease: How Far from Clinical Translation?
Previous Article in Special Issue
An Uncommon Case of Moyamoya Syndrome Is Accompanied by an Arteriovenous Malformation with the Involvement of Dural Arteries
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
IJMS
Volume 25
Issue 2
10.3390/ijms25021141
ijms-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Review

Regenerative Peripheral Nerve Interfaces (RPNIs) in Animal Models and Their Applications: A Systematic Review

by
Jorge González-Prieto
1,2,
Lara Cristóbal
1,2,
Mario Arenillas
3,
Romano Giannetti
4,
José Daniel Muñoz Frías
4,
Eduardo Alonso Rivas
4,
Elisa Sanz Barbero
5,
Ana Gutiérrez-Pecharromán
6,
Francisco Díaz Montero
7 and
Andrés A. Maldonado
1,2,*
1
Peripheral Nerve Unit, Department of Plastic Surgery, University Hospital of Getafe, 28905 Madrid, Spain
2
Department of Medicine, Faculty of Biomedical Science and Health, Universidad Europea de Madrid, 28670 Madrid, Spain
3
Animal Medicine and Surgery Department, Complutense University of Madrid, 28040 Madrid, Spain
4
Institute for Research in Technology, ICAI School of Engineering, Comillas Pontifical University, 28015 Madrid, Spain
5
Peripheral Nerve Unit, Neurophysiology Department, University Hospital of Getafe, 28905 Madrid, Spain
6
Peripheral Nerve Unit, Pathological Anatomy Department, University Hospital of Getafe, 28905 Madrid, Spain
7
Department of Design, BAU College of Arts & Design of Barcelona, 28036 Barcelona, Spain
*
Author to whom correspondence should be addressed.
Int. J. Mol. Sci. 2024, 25(2), 1141; https://doi.org/10.3390/ijms25021141
Submission received: 23 November 2023 / Revised: 5 January 2024 / Accepted: 10 January 2024 / Published: 17 January 2024
(This article belongs to the Special Issue Translational Medicine of Vascular and Lymphatic Diseases: From the Molecule to the Clinic)
Browse Figure
Review Reports Versions Notes

Abstract

:
Regenerative Peripheral Nerve Interfaces (RPNIs) encompass neurotized muscle grafts employed for the purpose of amplifying peripheral nerve electrical signaling. The aim of this investigation was to undertake an analysis of the extant literature concerning animal models utilized in the context of RPNIs. A systematic review of the literature of RPNI techniques in animal models was performed in line with the PRISMA statement using the MEDLINE/PubMed and Embase databases from January 1970 to September 2023. Within the compilation of one hundred and four articles employing the RPNI technique, a subset of thirty-five were conducted using animal models across six distinct institutions. The majority (91%) of these studies were performed on murine models, while the remaining (9%) were conducted employing macaque models. The most frequently employed anatomical components in the construction of the RPNIs were the common peroneal nerve and the extensor digitorum longus (EDL) muscle. Through various histological techniques, robust neoangiogenesis and axonal regeneration were evidenced. Functionally, the RPNIs demonstrated the capability to discern, record, and amplify action potentials, a competence that exhibited commendable long-term stability. Different RPNI animal models have been replicated across different studies. Histological, neurophysiological, and functional analyses are summarized to be used in future studies.

1. Introduction

Regenerative Peripheral Nerve Interfaces (RPNIs) represent a groundbreaking approach at the intersection of biomedical engineering, neurology, and regenerative medicine. These interfaces have the potential to revolutionize the field of bionic prostheses by facilitating communication between the nervous system and external devices and deterring the development of neuromas [1,2,3,4,5,6,7]. Unlike traditional neural interfaces, which rely on electrodes implanted into nerves, RPNIs aim to create a more seamless connection by harnessing the regenerative capacity of peripheral nerves [8].
RPNIs involve surgically grafting a small segment of a patient’s muscle, typically from an area with low functional significance, to a region near a damaged nerve or a residual limb [6,9,10,11,12,13]. The regenerative nature of peripheral nerves allows the nerve to regrow, reinnervate, and revascularize the muscle graft in three to four months [6,9,14,15,16,17,18]. This results in the formation of a “bioelectrode” that can be utilized to transmit signals between the patient’s nervous system and prosthetic devices [10,19,20,21,22].
Animal models are integral to advancing our understanding of RPNIs in biomedical research. By replicating and studying the RPNI murine model across various contexts, researchers gain insights into its mechanisms and potential applications in neuroprosthetics and pain management [1,9,10,11,13,15,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48]. These models help to assess reproducibility, long-term viability, and functional changes in RPNI constructs. This knowledge is crucial for translating RPNI innovations into effective treatments for limb impairments and neurological conditions [5,12,49,50,51,52,53,54,55,56,57,58,59].
The aim of this study was to perform the first systematic literature review of the RPNI technique across animal models. The different applications and characteristics of each model are analyzed. We believe the knowledge of all of the different surgical techniques and the different histological, neurophysiological, and functional tests may be useful for future research projects involving RPNIs.

2. Materials and Methods

2.1. Search Strategy

A comprehensive literature review was executed by searching the MEDLINE/PubMed and Embase databases spanning from 1 January 1970, to 30 September 2023. The search process encompassed both automated and manual approaches, ensuring the identification of all pertinent literature. The adherence to the PRISMA statement (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) [60] guided the execution and reporting of this review. Employing English keywords along with Boolean logical operators, specifically “(RPNI) OR (Regenerative Peripheral Nerve Interfaces)”, facilitated the search process. Notably, no limitations were imposed during the search.

2.2. Selection Criteria (Figure 1)

We included articles written in either English or Spanish that either described or employed the RPNI technique. Exclusion criteria encompassed studies where the RPNI technique was not utilized or was applied in non-animal models. We omitted duplicated studies and articles from the same author or author groups if they were identical. The evaluation of titles, abstracts, and full text, as well as the application of inclusion and exclusion criteria, was carried out independently by two independent plastic surgeons (J.G. and A.A.M.). Full versions of potentially relevant studies were procured for further assessments. Additional articles were considered following a review of the references from the retrieved articles. In cases of disagreement between the two reviewers, resolution was achieved through discussion and consensus.
Ijms 25 01141 g001
Figure 1. PRISMA flow diagram.
Figure 1. PRISMA flow diagram.
Ijms 25 01141 g001

2.3. Data Extraction

The data were gathered using the software “Microsoft Excel for Mac, version 16.8 (23121017)”. The collected data encompassed various elements: the article database, the university center where the study took place, the publication year, the study’s objectives and categorized groups, the animal species, along with the total animal count used, specifics about the nerve and muscle utilized in constructing the RPNI, the design and model of RPNI construction, the selection of histological parameters (including muscle angiogenesis, tissue viability, muscle axonal regeneration, neuroma formation, and fibrosis/scarring), a subset of functional variables (encompassing stimulus intensity and localization, compound muscle action potential (CMAP), motor unit action potential (MUAP), compound sensory nerve action potential (CSNAP) measurements, latency periods, and maximum muscle force), the outcomes, and the average follow-up duration.
A comprehensive quantitative analysis of the quality and limitations of the selected studies was conducted. This process was carried out following the “10 Essential ARRIVE (Animal Research: Reporting In Vivo Experiments)” outlined in the guidelines of “ARRIVE guidelines 2.0” [61]. Each study was rated on a 10-point scale, considering the degree of compliance with the evaluated items. These criteria represent the minimum requirement of information necessary to ensure that reviewers and readers can assess the reliability of the presented findings.

3. Results

In the initial search results, one hundred and twenty articles were identified through manual searching. These one hundred and twenty articles underwent an initial screening process, during which sixteen were eliminated due to duplication. Additionally, forty-one articles were excluded based on their title or abstract, and twenty-eight more were excluded after a thorough examination of the full text. Among these exclusions, ten articles were discarded because they did not employ the RPNI technique, and fifty-nine were excluded as they did not involve an animal model of RPNI. As a result, the final review comprises thirty-five articles (Figure 1).
Among the thirty-five articles under consideration, thirty have been disseminated via MEDLINE/PubMed [1,3,9,10,11,13,15,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,46,47,48,62], while five have found their place in the Embase database [42,43,44,45,63].
The University of Michigan emerges as the foremost research institution in the domain of the RPNI technique employed in animal models, with a noteworthy presence in twenty-eight (80%) publications. In twenty-four instances, it stands alone as the primary research center, while in four instances, it collaborates with the universities of Alberta, British Columbia, Delaware, and Groningen. The remaining seven (20%) articles originate from the universities of Wuhan, Beijing, Florida, Cambridge, and Texas (Table 1).
Table 1. General data of studies.
Table 1. General data of studies.
Reference No.PMIDFirst AuthorDatabaseUniversityPublication YearStudy GroupsFollow-Up Time (Months)Quality Score
[23]36729137Ian C. SandoPubMedMichigan 20221—Control Full-thickness Skin (CFS), 2—Control De-epithelialized Skin (CDS), 3—Control Transected Nerve (CTN), 4—Dermal Sensory Interface (DS-RPNII)59
[24]34359056Carrie A. Kubiak PubMedMichigan 20211—8 mm MC-RPNI with epineural window, 2—8 mm MC-RPNI without epineural window, 3—13 mm MC-RPNI with epineural window, 4—13 mm MC-RPNI without epineural window310
[15]32176203 Shelby R. SvientekPubMedMichigan 20211—C-RPNI (compound regenerative peripheral nerve interface)96
[25]36161173Zheng WangPubMedWuhan 20221—Control, 2—NSR (nerve stump implantation inside a
fully innervated muscle), 3—RPNI		1.510
[26]35875668Jiaqing WuPubMed Beijing 20221—Control, 2—RPNI210
[11]30458876Christopher M. FrostPubMedMichigan 20181—Control, 2—Denervated, 3—RPNI59
[27]26859115Daniel UrsuPubMedMichigan 20161—Control, 2—Denervated, 3—RPNI48
[28]28438166Daniel UrsuPubMedMichigan 20171—Control, 2—RPNI48
[29]25569986Christopher M. FrostPubMedMichigan/IEEE20141—NerveStim, 2—DirectStim, 3—DirectSIS, 4—DirectPEDOT09
[30]25570372Nicholas B. LanghalsPubMedMichigan/IEEE20141—RPNI147
[62]27247270Zachary T. IrwinPubMedMichigan 20161—RPNI207
[13]33290586Yaxi HuPubMedMichigan and Groningen 20201—RPNI 150 mg, 2—RPNI 300 mg, 3—RPNI 600 mg, 4—RPNI 1200 mg, 5—Control39
[1]27294122Melanie G. UrbanchekPubMed Michigan and Delaware 20161—Silicone mesh, 2—Acellular muscle, 3—Acellular muscle with a conductive polymer (PEDOT)37
[31]35098950Shelby R. SvientekPubMedMichigan 20221—MC-RPNI, 2—Control37
[3]29432117Philip P. VuPubMedMichigan/IEEE20181—RPNI, 2—Control (ECR)129
[32]25570963Shoshana L. WooPubMedMichigan/IEEE20141—RPNI, 2—RPNI with Tibial anterior (TA) and Extensor hallucis longus (EHL) muscles excision1.58
[9]24867721Theodore A. KungPubMedMichigan 20131—RPNI with steel electrode, 2—RPNI + PEDOT, 3—Control with steel electrode, 4—RPNI + PEDOT78
[33]25942171Andrej NedicPubMedMichigan 20141—Control, 2—RPNI, 3—DenevatedNot specified8
[34]25942129Christopher M. FrostPubMedMichigan 20141—Control, 2—RPNI, 3—Denervated58
[35]25942128John V LarsonPubMedMichigan 20141—Control, 2—RPNI48
[36]22456363Christopher M. FrostPubMedMichigan 20121—RPNI with steel electrode, 2—RPNI + PEDOTNot specified10
[10]26502083Ian C. SandoPubMedMichigan 20161—Epimysial electrode + bipolar/monopolar stimulation, 2—Intramuscular electrode + bipolar/monopolar stimulation48
[37]32413377Benjamin S. SpearmanPubMedUniversity of Florida20201—RPNI TEENI Not specified6
[38]36204848Zheng WangPubMedWuhan 20221—RPNI, 2—NSM (nerve stump implantation inside a fully innervated muscle), 3—Denervated/control210
[39]25942172Zachary P FrenchPubMedMichigan 20141—Control, 2—RPNI58
[40]35998559Eric W AtkinsonPubMedUniversity of Florida20221—RPNI MARTEENI2.58
[41]19744916Stéphanie P. LacourPubMedCambridge 20091—Group 1, 2—Group 2, 3—Group 338
[63]L71587711Zachary T. IrwinEmbaseMichigan 20141—RPNI65
[42]L71676463Shoshana WooEmbaseMichigan 20141—Extensor digitorum longus (EDL), 2—Biceps femoris, 3—Rectus femoris, 4—Gastrocnemius, 5—Vastus medialis48
[43]L71254630Ziya BaghmanliEmbaseMichigan 20111—Exposed soleus muscle not transferred or neurotized, 2—Soleus muscle transferred and neurotized, 3—Soleus muscle transferred, but not neurotized15
[45]L71606159Ian C SandoEmbaseMichigan 20141—Control, 2—RPNI56
[44]L71587616Bongkyun KimEmbaseTexas 20141- RPNINot specified5
[46]37265342Jenna-Lynn B. SengerPubMedMichigan, Alberta and British Columbia 20231—Target muscle reinnervation (TMR), 2—RPNI, 3—Neuroma excision, 4—Neuroma in situ1.510
[47]37227138Amir DehdashtianPubMedMichigan 20231—Neuroma, 2—RPNI, 3—Control29
[48]37400949Jenna-Lynn SengerPubMed Michigan, Alberta and British Columbia 20231—Inlay-RPNI, 2—Burrito-RPNI, 3—Control49
The average duration of follow-up for the animal subjects spanned 4.7 months (range, 0–20 months). The longest-running research extended for twenty months [62].
With the purpose of assessing the quality of the included research, a comprehensive quantitative analysis of the 35 studies was conducted. The evaluation resulted in a final average score of 8 out of 10, demonstrating a strong level of compliance with minimum reporting standards.

3.1. Type of Models (Table 2)

3.1.1. Species Selection and Sample Size

The selection of animal species for research purposes predominantly featured rats in thirty-two (91%) instances [1,9,10,11,13,15,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48], with Rhesus macaques employed on the remaining three occasions [3,62,63]. The sample size across these investigations exhibits a range from 2 to 90 specimens, averaging 20 animals per study.
Table 2. RPNI models and components of studies.
Table 2. RPNI models and components of studies.
Reference No.AnimalNo. of AnimalsRPNI DesignNerveMuscleRPNI ModelAim
[23]Rat40Burrito RPNI Sural Not specifiedSensible (DS-RPNI)HA, NA
[24]Rat37Burrito RPNI (nerve in-continuity)Common peronealEDL (Extensor digitorum longus)Motor (MC-RPNI)HA, NA
[15]RatNot specifiedInlay RPNICommon peronealEDLMixed (C-RPNI)HA, NA
[25]Rat60Inlay RPNISciaticAdductor magnusMotor NP
[26]Rat22Burrito RPNI SciaticEDLMotor NP, HA
[11]Rat6Inlay RPNICommon peronealEDLMotor MP, NA
[27]Rat6Inlay RPNIPeroneal and tibialEDLMotor NA
[28]Rat4Inlay RPNICommon peroneal and tibialEDLMotor NA
[29]Rat5Not specifiedCommon peronealEDLMotor NA
[30]RatNot specifiedInlay RPNICommon peronealEDLMotor HA, NA
[62]Rhesus macaque2 (9 RPNIs in total)Burrito RPNI Median and radialFlexor carpi radialis (FCR), flexor digitorum superficialis (FDS), and extensor digitorum communis (EDC)Motor MP, HA, NA
[13]Rat30Inlay RPNICommon peronealSemimembranosusMotor HA, NA
[1]Rat25Burrito RPNI Common peronealSoleusMotor NP, HA
[31]Rat12Burrito RPNI (without nerve section)Common peronealEDLMotor HA, NA
[3]Rhesus macaque2 (7 RPNIs in total)Burrito RPNI Median and radialFlexor digitorum profundus (FDP), FDS, and EDCMotor MP, NA
[32]Rat18Inlay RPNICommon peronealEDLMotor NA
[9]Rat16Inlay RPNICommon peronealEDLMotor HA, NA
[33]Rat9Not specifiedTibialSoleusMotor NA
[34]Rat6Not specifiedTibialSoleusMotor MP, NA
[35]Rat12Not specifiedSural EDLMotor HA, NA
[36]Rat18Inlay RPNICommon peronealEDLMotor NA
[10]Rat8Not specifiedCommon peroneal and tibialEDLMotor MP, HA, NA
[37]Rat3Not specifiedSciaticNot specifiedMotor NA
[38]Rat90Burrito RPNI SciaticAdductor magnusMotor NP, HA
[39]Rat10Not specifiedCommon peronealEDLMotor NA
[40]Rat5Not specifiedSciaticNot specifiedMotor NA
[41]Rat30Not specifiedSciaticNot specifiedMotor HA
[63]Rhesus macaqueNot specifiedNot specifiedMedian FDS, FDP, and flexor pollicis longus (FPL)Motor MP, NA
[42]Rat20Not specifiedCommon peronealEDL, biceps femoris, rectus femoris, gastrocnemius, and vastus medialisMotor NA
[43]RatNot specifiedNot specifiedTibialSoleusMotor NA
[45]Rat5Not specifiedCommon peronealEDLMotor NA
[44]RatNot specifiedNot specifiedSciaticTibialis anterior, soleus, and vastus lateralis Motor NA
[46]Rat36Inlay RPNITibialEDL and biceps femorisMotor NP, HA
[47]Rat36Inlay RPNITibialEDLMotor NP, HA
[48]Rat18Inlay RPNI and Burrito RPNITibialEDLMotor NP, HA
NP = Neuroma prevention, MP = Myoelectric prostheses, HA = Histological analysis, NA = Neurophysiological analysis.

3.1.2. RPNI Construction Designs

Two distinct designs for RPNI construction are prevalent among the studies: the Inlay-RPNI (in which the nerve is inset into the muscle graft and secured within an intact muscle belly) in thirteen (37%) articles [9,11,13,15,25,27,28,30,32,36,46,47,48] and the Burrito-RPNI (in which the muscle graft is wrapped around the distal nerve stump) in nine (26%) articles [1,3,23,24,26,31,38,48,62]. However, fourteen articles do not specify the particular model employed [10,29,33,34,35,37,39,40,41,42,43,44,45,63].
A different type of Burrito RPNI construction has been published [31] using a segment of a free muscle graft wrapping an intact peripheral nerve (the muscle is placed above the epineurium of a nerve, which is not sectioned).

3.1.3. Nerve and Muscle Selection

In constructing the RPNI, the common peroneal nerve takes precedence in seventeen (49%) cases [1,9,10,11,13,15,24,27,28,29,30,31,32,36,39,42,45], and in three of these, it is combined with the tibial nerve [10,27,28]. The tibial nerve is employed in nine (26%) studies [10,27,28,33,34,43,46,47,48]. Less frequently used nerves include the sciatic nerve in seven (20%) studies [25,26,37,38,40,41,44], the sural nerve in two (6%) studies [23,35], the median nerve in three (9%) studies [3,62,63] and the radial nerve in two (6%) instances [3,62], both of them in conjunction with the median nerve.
The extensor digitorum longus (EDL) muscle emerges as the preferred choice for RPNI construction in twenty (57%) instances [9,10,11,15,24,26,27,28,29,30,31,32,35,36,39,42,45,46,47,48]. Other less frequently selected muscles include the soleus muscle in five (14%) studies [1,33,34,43,44], the flexor digitorum superficialis (FDS) in three (9%) [3,62,63], and the adductor magnus [25,38], extensor digitorum communis (EDC) [3,62], flexor digitorum profundus (FDP) [3,63], and biceps femoris [42,46] in two (6%) studies each. Additionally, the flexor pollicis longus (FPL) [63], flexor carpi radialis (FCR) [62], semimembranosus [13], rectus femoris [42], gastrocnemius [42], vastus medialis [42], vastus lateralis [44], and tibialis anterior [44] are employed in one study each. Four articles omit the specification regarding the muscle utilized for RPNI construction [23,37,40,41].

3.1.4. Motor vs. Sensory Model

In the realm of RPNI animal models, the motor model is featured in thirty-three (94%) articles [1,3,9,10,11,13,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,62,63], the sensory model (DS-RPNI) in a single study [23], and the mixed model (C-RPNI) in another study [15].

3.2. Aim of the Study

We found four main types of studies regarding the research question:
  • Aim 1: Neuroma prevention (NP) [1,25,38,46,47,48]. These groups of six (17%) publications seek to assess the efficacy of RPNI in preventing the development of neuromas and alleviating neuropathic pain.
  • Aim 2: Myoelectric prostheses development (MP) [3,10,11,34,62,63]. This set of six (17%) studies focuses on examining and evaluating RPNI for its possible use within myoelectric prosthetic devices.
  • Aim 3: Histological analysis (HA) [1,9,10,13,15,23,24,26,30,31,35,38,41,46,47,48,62]. This series of seventeen (49%) articles primarily concentrates on assessing the muscle viability associated with RPNI construction.
  • Aim 4: Neurophysiological analysis (NA) [3,9,10,11,13,15,23,24,27,28,29,30,31,32,33,34,35,36,37,39,40,42,43,44,45,62,63]. This research group of twenty-seven (77%) articles is dedicated to enhancing and streamlining the acquisition and amplification of electrical signals from the RPNI muscle, aiming to optimize their application.

3.3. Histological Analysis (Table 3)

Histological analysis was performed in eighteen studies. The assessment of tissue viability in RPNIs yielded satisfactory results in all of these eighteen articles [1,9,10,13,15,23,24,26,30,31,35,38,41,44,46,47,48,62]. It has been noted that tissue viability diminishes proportionally with an increasing muscle graft mass surpassing 300 mg [13]. Analytical methodologies encompass direct visual examination through electron microscopy, staining procedures using hematoxylin-eosin, Masson’s trichrome, and the deployment of anti-desmin monoclonal antibodies (D33), as well as comparisons between the initial and final muscle graft weights and an evaluation of muscular response to electrical nerve stimulation.
The evaluation of muscular neoangiogenesis in RPNIs reveals robust outcomes in the fourteen studies where it was assessed through a histopathological analysis [1,9,10,13,15,23,24,30,31,35,41,46,47,62]. The muscular neoangiogenesis deteriorates in direct correlation with an increase in the muscle graft mass exceeding 300 mg [13]. Various techniques employed for analysis encompass direct visual examination via electron microscopy, staining techniques, such as hematoxylin-eosin, Masson’s trichrome, and DAPI (4′,6-diamidino-2-phenylindole) protocols, and the application of anti-Pzero and anti-RECA1 monoclonal antibodies.
Axonal regeneration was confirmed in the sixteen articles that undertook a histopathological analysis in this regard [1,9,13,15,23,24,26,30,31,35,40,41,44,46,47,62]. A noteworthy observation underscores that axonal regeneration deteriorates with an increase in the muscle graft mass beyond 300 mg [13]. Several techniques applied for analysis include direct visual inspection through electron microscopy and staining techniques incorporating hematoxylin-eosin, Toluidine blue, and acetylcholinesterase, as well as the DAPI protocol, anti-filament antibodies, anti-alpha bungarotoxin, anti-neurofilament 200 (NF 200), anti-neurofilament H (NF H), anti-neurofilament S100 (NF S100), anti-Pzero, and anti-RECA1 antibodies. Additionally, the muscle response to nerve electrical stimulation contributes to the assessment.
Neuroma formation within the RPNI was evaluated in twelve articles [1,9,13,15,23,24,26,31,38,46,47,48]. Generally, neuroma formation was not evident in the RPNI; however, it has been observed to increase proportionally with an escalation in the muscle graft mass exceeding 300 mg [13]. The rate of neuroma formation is higher when employing the targeted muscle reinnervation (TMR) technique as opposed to RPNI and with the Burrito-RPNI in comparison to the Inlay-RPNI [46,48]. Analytical techniques encompass direct visual examination through electron microscopy and staining procedures involving hematoxylin-eosin, Toluidine blue, and Masson’s trichrome, as well as the use of anti-alpha bungarotoxin and anti-neurofilament 200 (NF200) monoclonal antibodies and ultrasonography.
Fibrosis formation within the RPNI was scrutinized in sixteen articles [1,9,10,13,15,23,24,26,30,31,35,38,40,46,47,62]. In general, fibrosis formation is not conspicuous in the RPNI; however, it has been observed to increase proportionally with an augmentation in the muscle graft mass beyond 300 mg [13]. Notably, the rate of fibrosis formation is higher when the electrode is positioned intramuscularly, but lower when it is placed epimysially [10]. Analytical techniques encompass direct visual examination via electron microscopy and staining techniques employing hematoxylin, eosin, and Masson’s trichrome, as well as the utilization of anti-alpha smooth muscle actin (α-SMA) filament monoclonal antibodies.
The array of studies encompasses other investigations, including the quantification of neuronal density, measurement of the apoptosis index via the Terminal Deoxynucleotidyl Transferase-Mediated dUTP Nick-End Labeling (TUNEL) method, measurement of marker expression (Bax, BCL-2, and NTs), and the assessment of the degree of autotomy [25,26].
Table 3. Histological analysis of studies.
Table 3. Histological analysis of studies.
Reference No.Histology
Muscular Neoangiogenesis Tissue Viability Axonal Regeneration Neuroma Formation Fibrosis Formation
[23]Good in all (Hematoxylin-eosin (HE) and trichrome stains)Good in all (Hematoxylin-eosin (HE) and trichrome stains)Yes (Anti-filament antibodies)Small neuromas in control transected nerve groupNo (Antifilament antibodies)
[24]Good (HE stain)Good (HE stain)Yes (HE stain)No (HE stain)No (HE stain)
[15]GoodGoodYesNoNo
[25]Not evaluatedNot evaluatedNot evaluatedNot evaluatedNot evaluated
[26]Not evaluatedGoodYes (Anti-neurofilament 200 antibodies)Lower risk (Ultrasounds)No in RPNI group (α-SMA immunohistochemistry)
[11]Not evaluatedNot evaluatedNot evaluatedNot evaluatedNot evaluated
[27]Not evaluatedNot evaluatedNot evaluatedNot evaluatedNot evaluated
[28]Not evaluatedNot evaluatedNot evaluatedNot evaluatedNot evaluated
[29]Not evaluatedNot evaluatedNot evaluatedNot evaluatedNot evaluated
[30]Good (HE stain)Good (HE stain)No denervation data (HE stain)Not evaluatedNo (HE stain)
[62]Good (HE stain)Good (HE stain)Good reinnervation (Electrical stimulation)Not evaluatedNo (HE stain)
[13]Good in group 1 and 2 (HE stain, Masson’s trichrome and von Willebrand factor (vwf))Good in group 1 and 2. Fibrosis and central atrophy in groups 3 and 4 (HE stain and Masson’s trichrome)Best in group 1 and 2 (Toluidine blue)Present in group 5 (Toluidine blue)Fibrosis and central atrophy in groups 3 and 4 (HE and Masson’s trichrome stain).
[1]Good (HE stain)Good (HE stain and anti-desmin staining protocol)Good (Acetylcholinesterase stain)No (HE stain)No (HE stain)
[31]Good (HE stain)Good (HE stain)Yes (Anti-filament and alpha-bungarotoxin antibodies)No (HE stain)No (HE stain)
[3]Not evaluatedNot evaluatedNot evaluatedNot evaluatedNot evaluated
[32]Not evaluatedNot evaluatedNot evaluatedNot evaluatedNot evaluated
[9]Good (Masson’s trichrome and electron microscopy)Good (Masson’s trichrome, RPNI initial/final weight comparison, and electron microscopy)Good (Anti-neurofilament 200 and anti-alpha-bungarotoxin antibodies)No (Anti-neurofilament 200 and anti-alpha-bungarotoxin antibodies)No (Masson’s trichrome and electron microscopy)
[33]Not evaluatedNot evaluatedNot evaluatedNot evaluatedNot evaluated
[34]Not evaluatedNot evaluatedNot evaluatedNot evaluatedNot evaluated
[35]Good (Histomorphometric and immunohistochemical techniques)Good (Histomorphometric and immunohistochemical techniques)Good reinnervation (Electrical stimulation)Not evaluatedNo (Histomorphometric and immunohistochemical techniques)
[36]Not evaluatedNot evaluatedNot evaluatedNot evaluatedNot evaluated
[10]Good (Masson’s Trichrome)Good (Masson’s Trichrome)Not evaluatedNot evaluatedFibrous capsule in group 1 and fibrosis in group 2 (Masson’s trichrome)
[37]Not evaluatedNot evaluatedNot evaluatedNot evaluatedNot evaluated
[38]Not evaluatedGood (Masson’s Trichrome)Not evaluatedPresent in groups 2 and 3. No neuromas in group 1 (Masson trichrome and Toluidine blue)Lower in RPNI (Anti-α-SMA antibodies)
[39]Not evaluatedNot evaluatedNot evaluatedNot evaluatedNot evaluated
[40]Not evaluatedNot evaluatedGood (Anti-neurofilament H, neurofilament S100, and DNA antibodies)Not evaluatedFibrous capsule present around the electrode
[41]Good (DAPI protocol, anti-Pzero antibodies, and anti-RECA1 antibodies)Good (DAPI protocol, anti-Pzero antibodies, and anti-RECA1 antibodies)Good (DAPI protocol, anti-Pzero antibodies, and anti-RECA1 antibodies)Not evaluatedNot evaluated
[63]Not evaluatedNot evaluatedNot evaluatedNot evaluatedNot evaluated
[42]Not evaluatedNot evaluatedNot evaluatedNot evaluatedNot evaluated
[43]Not evaluatedNot evaluatedNot evaluatedNot evaluatedNot evaluated
[45]Not evaluatedNot evaluatedNot evaluatedNot evaluatedNot evaluated
[44]Not evaluatedGood (Response to electrical stimulation)Good reinnervation (Electrical stimulation)Not evaluatedNot evaluated
[46]GoodGoodGood (Anti-neurofilament 200 and alpha-bungarotoxin antibodies)Lower in RPNI and TMR, although similar between both groupsLower in RPNI
[47]Good (HE stain)Good (HE stain)Good (HE stain)No in RPNI groupNo in RPNI group
[48]Not evaluatedGoodNot evaluatedGreater in Burrito-RPNI than in Inlay-RPNINot evaluated

3.4. Neurophysiological Analysis (Table 4)

The stimulus modality included electrical stimulation in nineteen (54%) studies [9,10,13,15,23,24,29,30,31,32,35,36,39,40,42,43,44,45,62] and mechanical stimulation in nine (26%) studies [1,3,11,23,27,28,33,34,63]. Of the latter, one study employed monofilaments [11,34], three utilized a treadmill [27,28,33], and one employed nociceptive tactile stimuli [1]. In addition, in two studies conducted on macaques, voluntary finger movements served as the stimulus source [3,63].
In the case of the most prevalent model (Inlay RPNI using EDC and tibial/peroneal nerve in rats) [9,11,15,27,28,30,32,36,46,47,48], the average stimulus intensity was 49 microamperes (μA) with a range of 5 to 1500 μA. The mean CMAP was 11.45 millivolts (mV) ranging from 2.79 to 7.05 mV, the mean CSNAP measured 119.47 microvolts (μV) ranging from 104.6 to 134.34 μV, and the mean latency was 2.295 milliseconds (ms) ranging from 1.05 to 4.09 ms. The maximum muscle strength was not assessed in any of these models.
In the case of another common model (Burrito RPNI using EDC and tibial/peroneal nerve in rats) [24,31,48], the average CMAP measured 4.33 mV with a range of 0.75 to 35.3 mV, the average CSNAP was 123.3 μV with a range of 78.6 to 206.6 μV, and the mean latency was 1.175 ms with a range of 0.8 to 1.55 ms. The mean maximum muscle contraction strength was 2478.8 millinewtons (mN) with a range of 2226.7 to 2933.9 mN. The stimulus intensity was not recorded in any of these models.
When considering Rhesus macaques models [3,62,63], the average stimulus intensity in the nerve was 10.5 μA with a range of 1 to 20 μA, and in the muscle, it was 45 μA with a range of 30 to 90 μA. The average CMAP was 500 mV with a range of 400 to 600 mV. The maximum muscle strength was not evaluated in any of these models, and stimulus intensity data were not recorded for these models as well.
Table 4. Neurophysiological analysis of studies.
Table 4. Neurophysiological analysis of studies.
Reference No.Principal TestNeurophysiology
Stimulus Intensity Stimulus Location CMAP/MUP/CSNAP Latency Maximum Muscle Contraction Strength
[23]Electrical and mechanical stimulation0–800 μASural nerveMechanical stimulation: 0.06 mV. Electrical stimulation: 0.015 to 0.04 mVNot specifiedNot specified
[24]Electrical stimulationUntil reaching the maximum CMAPPeroneal nerve 3.67 ± 0.58 mV to 6.04 ± 1.01 mVNot specified1—2341 ± 114.3, 2—2398 ± 143.7, 3—2351 ± 290.2, 4—2832 ± 101.9 mN
[15]Electrical stimulationUntil reaching the maximum CMAP/CSNAPPeroneal nerve 8.7 +/− 1.6 mV at 3 months and 10.2 +/− 2.1 mV at 9 monthsNot specifiedNot specified
[25]Not specifiedNot specifiedNot specifiedNot specifiedNot specifiedNot specified
[26]Not specifiedNot specifiedNot specifiedNot specifiedNot specifiedNot specified
[11]Mechanical stimulation (monofilament)Not specifiedPeroneal nerveNot specifiedNot specifiedNot specified
[27]Mechanical stimulation (treadmill at 8.5–9 m/min)Not specifiedPeroneal and tibial nerve 0.75 to 1.0 mV during walking and <0.1 mV during restNot specifiedNot specified
[28]Mechanical stimulation (treadmill at 8.5–9 m/min)Not specifiedPeroneal and tibial nerve 0.75 to 1.0 mV during runningNot specifiedNot specified
[29]Electrical stimulationUntil reaching the maximum muscle contraction strength Peroneal nerve and EDL Not specifiedNot specifiedThe maximum specific muscle force was statistically greater in group 1 than group 2
[30]Electrical stimulation400–1500 μAPeroneal nerve and EDL Until >4 mVNot specifiedNot specified
[62]Electrical stimulation1000–20,000 μA in nerve y 30,000–60,000 μA in muscleFCR, FDS and EDCNot specifiedNot specifiedNot specified
[13]Electrical stimulation0–15,000 μA with periodic increments of 30 μAPeroneal nerve 1—6.6 ± 1.3 mV; 2—4.7 ± 0.8 mV; 3—3.1 ± 0.6 mV; 4—2.3 ± 0.7 mVNot specified1—289.0 ± 43.3 mN, 2—257.7 ± 49.1 mN, 3—198.8 ± 71.7 mN, 4—116.4 ± 31.0 mN
[1]Mechanical stimulation (painful stimulus)Not specifiedPeroneal nerve Not specifiedNot specifiedNot specified
[31]Electrical stimulationNot specifiedPeroneal nerve3.28 mV ± 0.49 mV. (CNAP 119.47 μV ± 14.87 μV)0.8–1.55 ms2451 ± 115 mN en RPNI y 2497 ± 122 mN in control
[3]Mechanical stimulation (finger movements)Not specifiedFDP, FDS, and EDCNot specifiedNot specifiedNot specified
[32]Electrical stimulation5–505 μAPeroneal nerve 1—21.6 ± 9.7 mV. 2—14. ± 6.5 mV1—3.21 ± 0.53 ms. 2—3.56 ± 0.53 msNot specified
[9]Electrical stimulationUntil reaching the maximum CMAPPeroneal nerve 1—3.52–6.05 mV, 2—5.3–8.19 mV, 3—10.18–11.59 mV, 4—10.5–11.33 mVNot specifiedNot specified
[33]Mechanical stimulation (treadmill)Not specifiedNot specifiedNot specifiedNot specifiedNot specified
[34]Mechanical stimulation (monofilament)Not specifiedNot specifiedNot specifiedNot specifiedNot specified
[35]Electrical stimulation143.8 μA at 3 months and 99.6 μA at 4 monthsSural nerve0.68 mV,
at 3 months and 2.27 mV at 4 months		Similar to control groupNot specified
[36]Electrical stimulation1—140 ± 50 μA, 2—51 ± 20 μAPeroneal nerve1—19.4 ± 4.8 mV, 2—23.4 ± 11.9 mV1—1.21 ± 0.16 ms, 2—1.2 ± 0.16 msNot specified
[10]Electrical stimulationUntil reaching the maximum CMAPPeroneal and tibial nerve Not specifiedNot specifiedNot specified
[37]Not specifiedNot specifiedNot specifiedNot specifiedNot specifiedNot specified
[38]Not specifiedNot specifiedNot specifiedNot specifiedNot specifiedNot specified
[39]Electrical stimulationUntil reaching the maximum CMAPPeroneal nerveNot specifiedNot specifiedNot specified
[40]Electrical stimulation200–3000 μASciatic nerve50–500 μVNot specifiedNot specified
[41]Not specifiedNot specifiedNot specifiedNot specifiedNot specifiedNot specified
[63]Mechanical stimulation (finger movements)Not specifiedMedian nerve0.4–0.6 mVNot specifiedNot specified
[42]Electrical stimulationNot specifiedPeroneal nerve1—6.7 mV; 2—5–1.16 mVNot specified1—500 mN; 2—5–137 mN
[43]Electrical stimulationNot specifiedTibial nerve1—5.8 ± 3.82 mV; 2—1.4 ± 0.9 mV1—1.9 ± 0.49 ms; 2—2.2 ± 0.66 msNot specified
[45]Electrical stimulationNot specifiedPeroneal nerve1—24.2 ± 9.4 mV; 2—6.8 ± 7.1 mVNot specified1—2658 ± 558 mN; 2—1627 ± 493 mN
[44]Electrical stimulationNot specifiedNot specifiedNot specifiedNot specifiedNot specified
[46]Not specifiedNot specifiedNot specifiedNot specifiedNot specifiedNot specified
[47]Not specifiedNot specifiedNot specifiedNot specifiedNot specifiedNot specified
[48]Not specifiedNot specifiedNot specifiedNot specifiedNot specifiedNot specified

4. Discussion

The University of Michigan’s prominent presence in twenty-eight out of the thirty-five reviewed articles underscores its leadership in researching the RPNI technique in animal models. We hope that other institutions will validate and advance RPNI applications in the near future.
Given that performing RPNIs is not technically difficult, we anticipate an increase in the utilization of animal models and RPNI applications for pain management in humans. A longer path is expected in the case of the RPNI and myoelectric prosthesis, as it entails the need for more extensive technical resources, including the prosthetic device itself and the connection between the RPNI and the prosthesis.

4.1. Type of Model

The predominance of rat models in thirty-two instances is a common practice due to their widespread use in biomedical research. Rhesus macaques, while representing a different order of magnitude in complexity, were utilized in only three studies [3,62,63]. While rats provide practical advantages, such as cost-effectiveness and ease of handling, the translation of findings to larger primates and ultimately to humans may face challenges given the considerable biological differences.
The distinction between Inlay-RPNI and Burrito-RPNI designs provides valuable insights into the diversity of methodologies. We have observed that the Inlay-RPNI design is recently more often used in published articles than the Burrito-RPNI design. A recent study has demonstrated that the Inlay-RPNI model yielded superior outcomes in preventing neuromas compared to the Burrito-RPNI [48]. In the near future, we anticipate the identification of the most suitable RPNI model for specific applications.
The preference for the common peroneal nerve and EDL muscle in RPNI construction is consistent across studies. We believe that the nerve and muscle selection is not so critical to reproduce the RPNI model. However, the combination of two nerves from the same extremity (such as peroneal and tibial nerve [10,27,28]) may induce difficulties in carrying out some basic activities, such as walking or feeding.
It is worth noting that the RPNI technique has been assessed in various clinical studies involving humans, showcasing promising outcomes in alleviating neuropathic pain and in the application of myoelectric prostheses. Nevertheless, future researchers should prioritize addressing the dearth of clinical trials that substantiate these findings [12,50,54,57,58,64,65].

4.2. Aim of the Study

We have categorized our analysis into four distinct aims based on the research question. This offers a structured approach to understanding the multifaceted aspects of RPNI applications. The identified aims (neuroma prevention, myoelectric prostheses development, histological analysis, and neurophysiological analysis) encompass a broad spectrum of RPNI applications, demonstrating the versatility and potential of this technique.
We think the use of the RPNI model for myoelectric prostheses could be the most promising application. Being able to obtain the information from different peripheral nerve fascicles could be a paradigm change in peripheral nerve surgery. However, we identified only six studies focusing mainly on myoelectric prosthesis development [3,10,11,34,62,63]. One of the main limitations of RPNIs is the difficulty of getting the electrical signal from the muscle to the prosthesis. As we have previously summarized, the low amplitude of the electrical signal and the small size of the muscle graft are the main drawbacks. A subcutaneous electromyographic recording could facilitate the acquisition, amplification, and transmission of the electrical signal from the RPNI to the prosthesis.

4.3. Histological Analysis

One of the main concerns when analyzing RPNIs is the blood supply of the muscle graft. Muscle tissue is known for its high demanding oxygen requirements [66,67]. The combination of these high muscle metabolic rates and the absence of an established vascular system may hinder efficient oxygen delivery, elevating the risk of complications, like necrosis. Muscular neoangiogenesis, tissue viability, axonal regeneration, or neuroma and fibrosis formation has been evaluated in eighteen publications. No necrosis or muscle graft failure was reported in the animal series analyzed in this review. However, the size of the muscle graft has been associated with the above parameters. Muscle grafts mass exceeding 300 mg presented with worse tissue viability and higher rates of complications, such us fibrosis [13].
Vascularized RPNIs (using vascularized muscle, but not a muscle graft) have been reported, and promising results focusing on neuropathic pain have been published [56,68,69,70]. Despite previous studies analyzing the vascularization of muscle grafts in standard RPNIs, we believe that vascularized RPNIs should yield more stable results. Vascularization of the RPNI is one of our primary concerns, particularly when considering the potential use of a needle to obtain an electric signal from the muscle graft.
One notable limitation within the examined studies lies in the deficiency of objectivity in the histological analysis of samples across diverse research investigations. This shortfall is attributed to the absence of standardized criteria that would facilitate the comparison of histological findings across these studies. The inclusion of subjective terms, such as “good”, “viable”, or “healthy” introduces inherent ambiguity, thereby impeding the ability to conduct comprehensive comparative analyses among the various studies. Addressing this limitation necessitates the establishment of clear and standardized criteria, which is crucial for promoting objectivity and enhancing the reliability of histological assessments in future research endeavors.

4.4. Neurophysiological Analysis

The inclusion of both electrical and mechanical stimulation (monofilaments, treadmill, and nociceptive tactile stimuli) in the studies contributes to a comprehensive understanding of RPNI outcomes. One of our concerns is that the maximum muscle strength [1,3,9,10,11,15,23,25,26,27,28,30,32,33,34,35,36,37,38,39,40,41,43,44,46,47,48,62,63] and the stimulus intensity [1,3,9,10,11,15,24,25,26,27,28,29,31,33,34,37,38,39,40,41,42,43,44,45,46,47,48,63] were not reported in some studies. Given the relatively short distance between the stimulation site and the RPNI, artefacts could potentially mask the proper reinnervation of the RPNI. We believe that receiving an electrical signal in such a small muscle is one of the major challenges in handling and transmitting that signal to a myoelectric prosthesis. Future studies will need to demonstrate how to optimize this signal and reliably capture the action potential despite electrical noise.

4.5. Limitations and Future Challenges

We believe that this systematic review will be very useful in aiding future researchers to enhance surgical techniques and the application of RPNIs across various animal models. Given the significant technical complexity involved in using RPNIs for electrical signal acquisition and myoelectric prosthesis control, we are convinced that refining the animal model of RPNIs could directly impact its application in human contexts. This advancement may signify a significant step towards optimizing procedures and the future viability of RPNIs in clinical applications.
The use of RPNI involves substantial challenges in its clinical implementation. Tissue viability (given its nature as non-vascularized muscle grafts) or limitations in detecting and amplifying electrical signals in RPNI directly impact their functional effectiveness. Transitioning RPNI models from an animal to a human setting presents potential obstacles, given the potential influence of physiological variations on their effectiveness and response. Finally, configuring and adapting patients to prostheses derived from RPNI pose challenges in terms of acceptance and optimal functionality in daily life. These aspects underscore the complexity and potential barriers to be addressed during the development and implementation of RPNI and their clinical applications.

5. Conclusions

To the best of our knowledge, this is the first systematic review of the RPNI technique in animal models. Murine models of RPNIs have consistently demonstrated promising results among several studies, particularly in the myoelectric prosthetics field and the prevention of neuropathic pain. Histological, neurophysiological, and functional analyses are summarized to be used in further studies. Forthcoming research should aim to validate these findings and continue to improve the synergy between humans and machines, advancing a more sophisticated interaction paradigm.

Author Contributions

Conceptualization, J.G.-P., L.C. and A.A.M.; methodology, J.G.-P., L.C. and A.A.M.; validation, J.G.-P., A.A.M. and L.C.; formal analysis, J.G.-P.; investigation, J.G.-P.; writing—original draft preparation, J.G.-P.; writing—review and editing, A.A.M., L.C., M.A., R.G., J.D.M.F., E.A.R., E.S.B., A.G.-P. and F.D.M.; supervision, A.A.M. and L.C.; funding acquisition, A.A.M. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by Instituto de Salud Carlos III (ISCIII) through the project PI22/00862 and co-funded by the European Union. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Urbanchek, M.G.; Kung, T.A.; Frost, C.M.; Martin, D.C.; Larkin, L.M.; Wollstein, A.; Cederna, P.S. Development of a Regenerative Peripheral Nerve Interface for Control of a Neuroprosthetic Limb. BioMed Res. Int. 2016, 2016, 5726730. [Google Scholar] [CrossRef] [PubMed]
  2. Kung, T.A.; Bueno, R.A.; Alkhalefah, G.K.; Langhals, N.B.; Urbanchek, M.G.; Cederna, P.S. Innovations in Prosthetic Interfaces for the Upper Extremity. Plast. Reconstr. Surg. 2013, 132, 1515–1523. [Google Scholar] [CrossRef] [PubMed]
  3. Vu, P.P.; Irwin, Z.T.; Bullard, A.J.; Ambani, S.W.; Sando, I.C.; Urbanchek, M.G.; Cederna, P.S.; Chestek, C.A. Closed-Loop Continuous Hand Control via Chronic Recording of Regenerative Peripheral Nerve Interfaces. IEEE Trans. Neural Syst. Rehabil. Eng. 2018, 26, 515–526. [Google Scholar] [CrossRef] [PubMed]
  4. Woo, S.L.; Kung, T.A.; Brown, D.L.; Leonard, J.A.; Kelly, B.M.; Cederna, P.S. Regenerative Peripheral Nerve Interfaces for the Treatment of Postamputation Neuroma Pain: A Pilot Study. Plast. Reconstr. Surg. Glob. Open 2016, 4, e1038. [Google Scholar] [CrossRef] [PubMed]
  5. Ganesh Kumar, N.; Kung, T.A. Regenerative Peripheral Nerve Interfaces for the Treatment and Prevention of Neuromas and Neuroma Pain. Hand Clin. 2021, 37, 361–371. [Google Scholar] [CrossRef] [PubMed]
  6. Kubiak, C.A.; Kemp, S.W.P.; Cederna, P.S. Regenerative Peripheral Nerve Interface for Management of Postamputation Neuroma. JAMA Surg. 2018, 153, 681–682. [Google Scholar] [CrossRef] [PubMed]
  7. Hooper, R.C.; Cederna, P.S.; Brown, D.L.; Haase, S.C.; Waljee, J.F.; Egeland, B.M.; Kelley, B.P.; Kung, T.A. Regenerative Peripheral Nerve Interfaces for the Management of Symptomatic Hand and Digital Neuromas. Plast. Reconstr. Surg. Glob. Open 2020, 8, e2792. [Google Scholar] [CrossRef]
  8. Biddiss, E.A.; Chau, T.T. Upper Limb Prosthesis Use and Abandonment: A Survey of the Last 25 Years. Prosthet. Orthot. Int. 2007, 31, 236–257. [Google Scholar] [CrossRef]
  9. Kung, T.A.; Langhals, N.B.; Martin, D.C.; Johnson, P.J.; Cederna, P.S.; Urbanchek, M.G. Regenerative Peripheral Nerve Interface Viability and Signal Transduction with an Implanted Electrode. Plast. Reconstr. Surg. 2014, 133, 1380–1394. [Google Scholar] [CrossRef]
  10. Sando, I.C.; Leach, M.K.; Woo, S.L.; Moon, J.D.; Cederna, P.S.; Langhals, N.B.; Urbanchek, M.G. Regenerative Peripheral Nerve Interface for Prostheses Control: Electrode Comparison. J. Reconstr. Microsurg. 2016, 32, 194–199. [Google Scholar] [CrossRef]
  11. Frost, C.M.; Ursu, D.C.; Flattery, S.M.; Nedic, A.; Hassett, C.A.; Moon, J.D.; Buchanan, P.J.; Brent Gillespie, R.; Kung, T.A.; Kemp, S.W.P.; et al. Regenerative Peripheral Nerve Interfaces for Real-Time, Proportional Control of a Neuroprosthetic Hand. J. Neuroeng. Rehabil. 2018, 15, 108. [Google Scholar] [CrossRef]
  12. Vu, P.P.; Vaskov, A.K.; Irwin, Z.T.; Henning, P.T.; Lueders, D.R.; Laidlaw, A.T.; Davis, A.J.; Nu, C.S.; Gates, D.H.; Gillespie, R.B.; et al. A Regenerative Peripheral Nerve Interface Allows Real-Time Control of an Artificial Hand in Upper Limb Amputees. Sci. Transl. Med. 2020, 12, eaay2857. [Google Scholar] [CrossRef]
  13. Hu, Y.; Ursu, D.C.; Sohasky, R.A. Regenerative Peripheral Nerve Interface (RPNI) Free Muscle Graft Mass and Function. Muscle Nerve 2021, 63, 421–429. [Google Scholar] [CrossRef] [PubMed]
  14. Baldwin, J.; Moon, J.D.; Cederna, P.S.; Urbanchek, M.G. Early Muscle Revascularization and Regeneration at the Regenerative Peripheral Nerve Interface. Plast. Reconstr. Surg. 2012, 130, 73. [Google Scholar] [CrossRef]
  15. Svientek, S.R.; Ursu, D.C.; Cederna, P.S.; Kemp, S.W.P. Fabrication of the Composite Regenerative Peripheral Nerve Interface (C-RPNI) in the Adult Rat. J. Vis. Exp. 2020, 156, e60841. [Google Scholar] [CrossRef]
  16. Urbanchek, M.G.; Wei, B.; Baghmanli, Z.; Sugg, K.B.; Cederna, P.S. Long-Term Stability of Regenerative Peripheral Nerve Interfaces (RPNI). Plast. Reconstr. Surg. 2011, 128, 88–89. [Google Scholar] [CrossRef]
  17. Urbanchek, M.G.; Baghmanli, Z.; Moon, J.D.; Sugg, K.B.; Langhals, N.B.; Cederna, P.S. Quantification of Regenerative Peripheral Nerve Interface Signal Transmission. Plast. Reconstr. Surg. 2012, 130, 55–56. [Google Scholar] [CrossRef]
  18. Urbanchek, M.G.; Moon, J.D.; Sugg, K.B.; Langhals, N.B.; Cederna, P.S.; Baghmanli, Z. Regenerative Peripheral Nerve Interface Function at 1 and 3 Months after Implantation. Plast. Reconstr. Surg. 2012, 130, 84. [Google Scholar] [CrossRef]
  19. Kuiken, T.A.; Li, G.; Lock, B.A.; Lipschutz, R.D.; Miller, L.A.; Stubblefield, K.A.; Englehart, K.B. Targeted Muscle Reinnervation for Real-Time Myoelectric Control of Multifunction Artificial Arms. JAMA 2009, 301, 619–628. [Google Scholar] [CrossRef]
  20. Ohnishi, K.; Weir, R.F.; Kuiken, T.A. Neural Machine Interfaces for Controlling Multifunctional Powered Upperlimb Prostheses. Expert Rev. Med. Devices 2007, 4, 43–53. [Google Scholar] [CrossRef]
  21. Urbanchek, M.G.; Wei, B.; Egeland, B.M.; Abidian, M.R.; Kipke, D.R.; Cederna, P.S. Microscale Electrode Implantation during Nerve Repair: Effects on Nerve Morphology, Electromyography, and Recovery of Muscle Contractile Function. Plast. Reconstr. Surg. 2011, 128, 270e–278e. [Google Scholar] [CrossRef] [PubMed]
  22. Baghmanli, Z.; Sugg, K.B.; Wei, B.; Shim, B.S.; Martin, D.C.; Cederna, P.S.; Urbanchek, M.G. Biological and Electrophysiologic Effects of Poly(3,4- Ethylenedioxythiophene) on Regenerating Peripheral Nerve Fibers Plast. Plast. Reconstr. Surg. 2013, 132, 374–385. [Google Scholar] [CrossRef]
  23. Sando, I.C.; Adidharma, W.; Nedic, A.; Ursu, D.C.; Mays, E.A.; Hu, Y.; Kubiak, C.A.; Sugg, K.B.; Kung, T.A.; Cederna, P.S.; et al. Dermal Sensory Regenerative Peripheral Nerve Interface for Reestablishing Sensory Nerve Feedback in Peripheral Afferents in the Rat. Plast. Reconstr. Surg. 2023, 151, 804e–813e. [Google Scholar] [CrossRef]
  24. Kubiak, C.A.; Svientek, S.R.; Dehdashtian, A.; Lawera, N.G.; Nadarajan, V.; Bratley, J.V.; Kung, T.A.; Cederna, P.S.; Kemp, S.W.P. Physiologic Signaling and Viability of the Muscle Cuff Regenerative Peripheral Nerve Interface (MC-RPNI) for Intact Peripheral Nerves. J. Neural Eng. 2021, 18, 0460d5. [Google Scholar] [CrossRef]
  25. Wang, Z.; Zhang, D.; Yi, X.Z.; Zhao, Y.; Yu, A. Effects of Regenerative Peripheral Nerve Interface on Dorsal Root Ganglia Neurons Following Peripheral Axotomy. Front. Neurosci. 2022, 16, 914344. [Google Scholar] [CrossRef]
  26. Wu, J.; Zhang, Y.; Zhang, X.; Lin, Z.; Li, G. Regenerative Peripheral Nerve Interfaces Effectively Prevent Neuroma Formation After Sciatic Nerve Transection in Rats. Front. Mol. Neurosci. 2022, 15, 938930. [Google Scholar] [CrossRef] [PubMed]
  27. Ursu, D.C.; Urbanchek, M.G.; Nedic, A.; Cederna, P.S.; Gillespie, R.B. In Vivo Characterization of Regenerative Peripheral Nerve Interface Function. J. Neural Eng. 2016, 13, 026012. [Google Scholar] [CrossRef] [PubMed]
  28. Ursu, D.; Nedic, A.; Urbanchek, M.; Cederna, P.; Gillespie, R.B. Adjacent Regenerative Peripheral Nerve Interfaces Produce Phase-Antagonist Signals during Voluntary Walking in Rats. J. Neuroeng. Rehabil. 2017, 14, 33. [Google Scholar] [CrossRef]
  29. Frost, C.M.; Cederna, P.S.; Martin, D.C.; Shim, B.S.; Urbanchek, M.G. Decellular Biological Scaffold Polymerized with PEDOT for Improving Peripheral Nerve Interface Charge Transfer. Conf. Proc. IEEE Eng. Med. Biol. Soc. 2014, 2014, 422–425. [Google Scholar]
  30. Langhals, N.B.; Woo, S.L.; Moon, J.D.; Larson, J.V.; Leach, M.K.; Cederna, P.S.; Urbanchek, M.G. Electrically Stimulated Signals from a Long-Term Regenerative Peripheral Nerve Interface. Conf. Proc. IEEE Eng. Med. Biol. Soc. 2014, 2014, 1989–1992. [Google Scholar]
  31. Svientek, S.R.; Wisely, J.P.; Dehdashtian, A.; Bratley, J.V.; Cederna, P.S.; Kemp, S.W.P. The Muscle Cuff Regenerative Peripheral Nerve Interface for the Amplification of Intact Peripheral Nerve Signals. J. Vis. Exp. 2022, 179, e63222. [Google Scholar] [CrossRef]
  32. Woo, S.L.; Urbanchek, M.G.; Leach, M.K.; Moon, J.D.; Cederna, P.; Langhals, N.B. Quantification of Muscle-Derived Signal Interference during Monopolar Needle Electromyography of a Peripheral Nerve Interface in the Rat Hind Limb. Conf. Proc. IEEE Eng. Med. Biol. Soc. 2014, 2014, 4382–4385. [Google Scholar]
  33. Nedic, A.; Ursu, D.; Moon, J.D.; Hassett, C.A.; Gillespie, R.B.; Langhals, N.B.; Cederna, P.S.; Urbanchek, M.G. Abstract 60: Signal Strength, Reliability, and Validity of Active Regenerative Peripheral Nerve Interface Device Operation during Voluntary Movement. Plast. Reconstr. Surg. 2014, 133, 71. [Google Scholar] [CrossRef]
  34. Frost, C.M.; Ursu, D.; Nedic, A.; Hassett, C.A.; Moon, J.D.; Gillespie, B.; Langhals, N.; Cederna, P.S.; Urbanchek, M.G. Abstract 18: Real-Time Proportional Control of a Neuroprosthetic Hand by a Rodent Regenerative Peripheral Nerve Interface. Plast. Reconstr. Surg. 2014, 133, 27–28. [Google Scholar] [CrossRef] [PubMed]
  35. Larson, J.V.; Urbanchek, M.G.; Moon, J.D.; Hunter, D.A.; Newton, P.; Johnson, P.J.; Wood, M.D.; Kung, T.A.; Cederna, P.S.; Langhals, N.B. Abstract 17: Prototype Sensory Regenerative Peripheral Nerve Interface for Artificial Limb Somatosensory Feedback. Plast. Reconstr. Surg. 2014, 133, 26–27. [Google Scholar] [CrossRef]
  36. Frost, C.M.; Wei, B.; Baghmanli, Z.; Cederna, P.S.; Urbanchek, M.G. PEDOT Electrochemical Polymerization Improves Electrode Fidelity and Sensitivity. Plast. Reconstr. Surg. 2012, 129, 933–942. [Google Scholar] [CrossRef] [PubMed]
  37. pearman, B.S.; Kuliasha, C.A.; Judy, J.W.; Schmidt, C.E. Integration of Flexible Polyimide Arrays into Soft Extracellular Matrix-Based Hydrogel Materials for a Tissue-Engineered Electronic Nerve Interface (TEENI). J. Neurosci. Methods 2020, 341, 108762. [Google Scholar] [CrossRef] [PubMed]
  38. Wang, Z.; Yi, X.-Z.; Yu, A.-X. Regenerative Peripheral Nerve Interface Prevents Neuroma Formation after Peripheral Nerve Transection. Neural Regen. Res. 2023, 18, 814–818. [Google Scholar]
  39. French, Z.P.; Carrothers, N.S.; Hassett, C.A.; Moon, J.D.; Langhals, N.B.; Cederna, P.S.; Urbanchek, M.G. Abstract 61: Characterization of Regenerative Peripheral Nerve Device Signaling during Evoked Maximal and Submaximal Fatiguing Conditions. Plast. Reconstr. Surg. 2014, 133, 72. [Google Scholar] [CrossRef]
  40. Atkinson, E.W.; Kuliasha, C.A.; Kasper, M.; Furniturewalla, A.; Lim, A.S.; Jiracek-Sapieha, L.; Brake, A.; Gormaley, A.; Rivera-Llabres, V.; Singh, I.; et al. Examining Thein Vivofunctionality of the Magnetically Aligned Regenerative Tissue-Engineered Electronic Nerve Interface (MARTEENI). J. Neural Eng. 2022, 19, 056010. [Google Scholar] [CrossRef]
  41. Lacour, S.P.; Fitzgerald, J.J.; Lago, N.; Tarte, E.; McMahon, S.; Fawcett, J. Long Micro-Channel Electrode Arrays: A Novel Type of Regenerative Peripheral Nerve Interface. IEEE Trans. Neural Syst. Rehabil. Eng. 2009, 17, 454–460. [Google Scholar] [CrossRef] [PubMed]
  42. Woo, S.; Urbanchek, M.G.; Leach, M.K.; Moon, J.D.; Cederna, P.S.; Langhals, N.B. Utilizing Nonvascularized Partial Skeletal Muscle Grafts in Peripheral Nerve Interfaces for Prosthetic Control. J. Am. Coll. Surg. 2014, 219, e136. [Google Scholar] [CrossRef]
  43. Baghmanli, Z.; Urbanchek, M.G.; Wei, B.; Sugg, K.B.; Kuzonv, W.M.; Cederna, P.S. Neurotization of Freely Transferred Muscle Grafts in a Regenerative Peripheral Nerve Interface. J. Am. Coll. Surg. 2011, 213, S98. [Google Scholar] [CrossRef]
  44. Kim, B.; Reyes, A.; Garza, B.; Ibarra, E.; Luna, R.; Flores, D.; Choi, Y. A Microchannel Neural Interface with Microwires for Recording and Stimulating Peripheral Nerves. In Proceedings of the 41st Neural Interfaces Conference, Dallas, TX, USA, 23–25 June 2014. [Google Scholar]
  45. Sando, I.C.; French, Z.P.; Hassett, C.A.; Moon, J.D.; Langhals, N.B.; Cederna, P.S.; Urbanchek, M.G. Regenerative Peripheral Nerve Signal During Fatigue Conditions. J. Am. Coll. Surg. 2014, 219, S88. [Google Scholar] [CrossRef]
  46. Senger, J.-L.B.; Hardy, P.; Thorkelsson, A.; Duia, S.; Hsiao, R.; Kemp, S.W.P.; Tenorio, G.; Rajshekar, M.; Kerr, B.J.; Chan, K.M.; et al. A Direct Comparison of Targeted Muscle Reinnervation and Regenerative Peripheral Nerve Interfaces to Prevent Neuroma Pain. Neurosurgery 2023, 93, 1180–1191. [Google Scholar] [CrossRef]
  47. Dehdashtian, A.; Timek, J.H.; Svientek, S.R.; Risch, M.J.; Bratley, J.V.; Riegger, A.E.; Kung, T.A.; Cederna, P.S.; Kemp, S.W.P. Sexually Dimorphic Pattern of Pain Mitigation Following Prophylactic Regenerative Peripheral Nerve Interface (RPNI) in a Rat Neuroma Model. Neurosurgery 2023, 93, 1192–1201. [Google Scholar] [CrossRef] [PubMed]
  48. Senger, J.-L.; Thorkelsson, A.; Wang, B.Y.; Chan, K.M.; Kemp, S.W.P.; Webber, C.A. “Inlay” Regenerative Peripheral Nerve Interface (RPNI) Is Superior to “Burrito” RPNI for Successful Treatment of Rat Neuroma Pain. Plast. Reconstr. Surg. 2023; Online ahead of print. [Google Scholar] [CrossRef]
  49. Kubiak, C.A.; Adidharma, W.; Kung, T.A.; Kemp, S.W.P.; Cederna, P.S.; Vemuri, C. Decreasing Postamputation Pain with the Regenerative Peripheral Nerve Interface (RPNI). Ann. Vasc. Surg. 2022, 79, 421–426. [Google Scholar] [CrossRef]
  50. Pejkova, S.; Nikolovska, B.; Srbov, B.; Tusheva, S.; Jovanoski, T.; Jovanovska, K.; Georgieva, G. Prophylactic Regenerative Peripheral Nerve Interfaces in Elective Lower Limb Amputations. Pril. Makedon Akad. Nauk. Umet. Odd. Med. Nauki 2022, 43, 41–48. [Google Scholar] [CrossRef]
  51. Sayegh, A.; Jaloux, C.; Witters, M.; Mayoly, A.; Kachouh, N. Update on Upper Limb Neuroma Management. J. Craniofac. Surg. 2023, 34, 1140–1143. [Google Scholar] [CrossRef]
  52. Richards, J.T.; Baird, M.D.; Tintle, S.M.; Souza, J.M.; Renninger, C.H.; Potter, B.K. Peripheral Nerve Management in Extremity Amputations. Orthop. Clin. N. Am. 2022, 53, 155–166. [Google Scholar] [CrossRef]
  53. de Lange, J.W.D.; Hundepool, C.A.; Power, D.M.; Rajaratnam, V.; Duraku, L.S.; Zuidam, J.M. Prevention Is Better than Cure: Surgical Methods for Neuropathic Pain Prevention Following Amputation—A Systematic Review. J. Plast. Reconstr. Aesthet. Surg. 2022, 75, 948–959. [Google Scholar] [CrossRef] [PubMed]
  54. Ganesh Kumar, N.; Kung, T.A.; Cederna, P.S. Regenerative Peripheral Nerve Interfaces for Advanced Control of Upper Extremity Prosthetic Devices. Hand Clin. 2021, 37, 425–433. [Google Scholar] [CrossRef]
  55. Hobusch, G.M.; Döring, K.; Brånemark, R.; Windhager, R. Advanced Techniques in Amputation Surgery and Prosthetic Technology in the Lower Extremity. EFORT Open Rev. 2020, 5, 724–741. [Google Scholar] [CrossRef] [PubMed]
  56. Valerio, I.; Schulz, S.A.; West, J.; Westenberg, R.F.; Eberlin, K.R. Targeted Muscle Reinnervation Combined with a Vascularized Pedicled Regenerative Peripheral Nerve Interface. Plast. Reconstr. Surg. Glob. Open 2020, 8, e2689. [Google Scholar] [CrossRef] [PubMed]
  57. Santosa, K.B.; Oliver, J.D.; Cederna, P.S.; Kung, T.A. Regenerative Peripheral Nerve Interfaces for Prevention and Management of Neuromas. Clin. Plast. Surg. 2020, 47, 311–321. [Google Scholar] [CrossRef]
  58. Lin, Z.; Yu, P.; Chen, Z.; Li, G. Regenerative Peripheral Nerve Interface Reduces the Incidence of Neuroma in the Lower Limbs after Amputation: A Retrospective Study Based on Ultrasound. J. Orthop. Surg. Res. 2023, 18, 619. [Google Scholar] [CrossRef]
  59. Xu, W.; Toyoda, Y.; Lin, I.C. Upper Extremity Prosthetics: Current Options and Future Innovations. J. Hand Surg. Am. 2023, 48, 1034–1044. [Google Scholar] [CrossRef] [PubMed]
  60. Liberati, A.; Altman, D.G.; Tetzlaff, J.; Mulrow, C.; Gøtzsche, P.C.; Ioannidis, J.P.A.; Clarke, M.; Devereaux, P.J.; Kleijnen, J.; Moher, D. The PRISMA Statement for Reporting Systematic Reviews and Meta-Analyses of Studies That Evaluate Health Care Interventions: Explanation and Elaboration. PLoS Med. 2009, 6, e1000100. [Google Scholar] [CrossRef]
  61. Percie du Sert, N.; Ahluwalia, A.; Alam, S.; Avey, M.T.; Baker, M.; Browne, W.J.; Clark, A.; Cuthill, I.C.; Dirnagl, U.; Emerson, M.; et al. Reporting Animal Research: Explanation and Elaboration for the ARRIVE Guidelines 2.0. PLoS Biol. 2020, 18, e3000411. [Google Scholar] [CrossRef]
  62. Irwin, Z.T.; Schroeder, K.E.; Vu, P.P.; Tat, D.M.; Bullard, A.J.; Woo, S.L.; Sando, I.C.; Urbanchek, M.G.; Cederna, P.S.; Chestek, C.A. Chronic Recording of Hand Prosthesis Control Signals via a Regenerative Peripheral Nerve Interface in a Rhesus Macaque. J. Neural Eng. 2016, 13, 046007. [Google Scholar] [CrossRef]
  63. Irwin, Z.T.; Schroeder, K.E.; Thompson, D.E.; Woo, S.L.; Langhals, N.B.; Urbanchek, M. GExtracting neuroprosthetic control signals from a regenerative peripheral nerve interface in a rhesus macaque. In Proceedings of the 100th Annual Clinical Congress of the American College of Surgeons, San Francisco, CA, USA, 26–30 October 2014. [Google Scholar]
  64. Vu, P.P.; Vaskov, A.K.; Lee, C.; Jillala, R.R.; Wallace, D.M.; Davis, A.J.; Kung, T.A.; Kemp, S.W.P.; Gates, D.H.; Chestek, C.A.; et al. Long-Term Upper-Extremity Prosthetic Control Using Regenerative Peripheral Nerve Interfaces and Implanted EMG Electrodes. J. Neural Eng. 2023, 20, 026039. [Google Scholar] [CrossRef] [PubMed]
  65. Pettersen, E.; Sassu, P.; Reinholdt, C.; Dahm, P.; Rolfson, O.; Björkman, A.; Innocenti, M.; Pedrini, F.A.; Breyer, J.M.; Roche, A.; et al. Surgical Treatments for Postamputation Pain: Study Protocol for an International, Double-Blind, Randomised Controlled Trial. Trials 2023, 24, 304. [Google Scholar] [CrossRef] [PubMed]
  66. Forgan, L.G.; Forster, M.E. Oxygen Dependence of Metabolism and Cellular Adaptation in Vertebrate Muscles: A Review. J. Comp. Physiol. B 2012, 182, 177–188. [Google Scholar] [CrossRef]
  67. Hoppeler, H.; Weibel, E.R. Structural and Functional Limits for Oxygen Supply to Muscle. Acta Physiol. Scand. 2000, 168, 445–456. [Google Scholar] [CrossRef] [PubMed]
  68. Suresh, V.; Schaefer, E.J.; Calotta, N.A.; Giladi, A.M.; Tuffaha, S.H. Use of Vascularized, Denervated Muscle Targets for Prevention and Treatment of Upper-Extremity Neuromas. J. Hand Surg. Glob. Online 2023, 5, 92–96. [Google Scholar] [CrossRef]
  69. Calotta, N.A.; Hanwright, P.J.; Giladi, A.; Tuffaha, S.H. Vascularized, Denervated Muscle Targets for Treatment of Symptomatic Neuromas in the Upper Extremity: Description of Operative Technique. Tech. Hand Up. Extrem. Surg. 2022, 26, 141–145. [Google Scholar] [CrossRef]
  70. Hui Ling Khoo, K.; Suresh, V.; Lee, E.; Harris, T.; Glass, C.; Tuffaha, S. Vascularized Denervated Muscle Targets: A Comparison with Regenerative Peripheral Nerve Interfaces to Determine Association Between Muscle Graft Size and Pain. Plast. Reconstr. Surg. Glob. Open 2022, 10, 16–17. [Google Scholar] [CrossRef]
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

González-Prieto, J.; Cristóbal, L.; Arenillas, M.; Giannetti, R.; Muñoz Frías, J.D.; Alonso Rivas, E.; Sanz Barbero, E.; Gutiérrez-Pecharromán, A.; Díaz Montero, F.; Maldonado, A.A. Regenerative Peripheral Nerve Interfaces (RPNIs) in Animal Models and Their Applications: A Systematic Review. Int. J. Mol. Sci. 2024, 25, 1141. https://doi.org/10.3390/ijms25021141

AMA Style

González-Prieto J, Cristóbal L, Arenillas M, Giannetti R, Muñoz Frías JD, Alonso Rivas E, Sanz Barbero E, Gutiérrez-Pecharromán A, Díaz Montero F, Maldonado AA. Regenerative Peripheral Nerve Interfaces (RPNIs) in Animal Models and Their Applications: A Systematic Review. International Journal of Molecular Sciences. 2024; 25(2):1141. https://doi.org/10.3390/ijms25021141

Chicago/Turabian Style

González-Prieto, Jorge, Lara Cristóbal, Mario Arenillas, Romano Giannetti, José Daniel Muñoz Frías, Eduardo Alonso Rivas, Elisa Sanz Barbero, Ana Gutiérrez-Pecharromán, Francisco Díaz Montero, and Andrés A. Maldonado. 2024. "Regenerative Peripheral Nerve Interfaces (RPNIs) in Animal Models and Their Applications: A Systematic Review" International Journal of Molecular Sciences 25, no. 2: 1141. https://doi.org/10.3390/ijms25021141

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop