Biomechanical characterization of cadaveric brachial plexus regions using uniaxial tensile tests.

INTRODUCTION: The proximal regions of the brachial plexus (roots, trunks) are more susceptible to permanent damage due to stretch injuries than the distal regions (cords, terminal branches). A better description of brachial plexus mechanical behavior is necessary to better understand deformation mechanisms in stretch injury. The purpose of this study was to model the biomechanical behavior of each portion of the brachial plexus (roots, trunks, cords, peripheral nerves) in a cadaveric model and report differences in elastic modulus, maximum stress and maximum strain. METHODS: Eight cadaveric plexi, divided into 47 segments according to regions of interest, underwent cyclical uniaxial tensile tests, using a BOSE® Electroforce® 3330 and INSTRON® 5969 material testing machines, to obtain the stress and strain histories of each specimen. Maximum stress, maximum strain and elastic modulus were extracted from the load-displacement and stress-strain curves. Statistical analyses used 1-way ANOVA with post-hoc Tukey HSD (Honestly Significant Difference) and Mann-Whitney tests. RESULTS: Mean elastic modulus was 8.65 MPa for roots, 8.82 MPa for trunks, 22.44 MPa for cords, and 26.43 MPa for peripheral nerves. Differences in elastic modulus and in maximum stress were statistically significant (p < 0.001) between proximal (roots, trunks) and distal (cords, peripheral nerves) specimens. CONCLUSIONS: Proximal structures demonstrated significantly smaller elastic modulus and maximum stress than distal structures. These data confirm the greater fragility of proximal regions of the brachial plexus.

Biomechanical characterization of cadaveric brachial plexus microstructure.

INTRODUCTION: Peripheral nerves consist of axons and connective tissue. The amount of connective tissue in peripheral nerves such as the brachial plexus varies proximally to distally. The proximal regions of the brachial plexus are more susceptible to stretch injuries than the distal regions. A description of the mechanical behavior of the peripheral nerve components is necessary to better understand the deformation mechanisms during stretch injuries. The purpose of this study was to model the biomechanical behavior of each component of the peripheral nerves (fascicles, connective tissue) in a cadaveric model and report differences in elastic modulus, maximum stress and maximum strain. METHODS: Forty-six specimens of fascicles and epi-perineurium were subjected to cyclical uniaxial tensile tests to obtain the stress and strain histories of each specimen, using a BOSE® Electroforce® 3330 and INSTRON® 5969 materials testing machines. Maximum stress, maximum strain and elastic modulus were extracted from the load-displacement and stress-strain curves, and analyzed using Mann-Whitney tests. RESULTS: Mean elastic modulus was 6.34 MPa for fascicles, and 32.1 MPa for connective tissue. The differences in elastic modulus and maximum stress between fascicles and connective tissue were statistically significant (p < 0.001). CONCLUSIONS: Peripheral nerve connective tissue showed significantly higher elastic modulus and maximum stress than fascicles. These data confirm the greater fragility of axons compared to connective tissue, suggesting that the greater susceptibility to stretch injury in proximal regions of the brachial plexus might be related to the smaller amount of connective tissue.

Cadaveric study of flexor digitorum profundus and superficialis and flexor pollicis longus innervation patterns for application in selective neurectomy.

PURPOSE: Spasticity management in finger flexors (flexor digitorum profundus and superficialis and flexor pollicis longus) is a challenge. Recent studies demonstrated the short- and long-term efficacy of selective and hyperselective neurectomy for the spastic upper limb. However, hyperselective neurectomy of flexor digitorum profundus and flexor digitorum superficialis branches was incomplete, without impairing their muscular body and function. This cadaveric study describes a novel medial approach in the forearm, to reach all the muscular branches: flexor digitorum superficialis and profundus and flexor pollicis longus. MATERIAL AND METHODS: Fourteen cadaveric fresh frozen upper limbs were used. The feasibility of the medial surgical approach was studied, as well as the number, length and point of emergence of the muscular branches from the median and ulnar nerves to the flexor pollicis longus, flexor digitorum profundus and flexor digitorum superficialis. RESULTS: The medial approach to the forearm gave access to all the muscular branches from the median and ulnar nerves to the flexor pollicis longus, flexor digitorum superficialis and flexor digitorum profundus, in all cases. A Martin Gruber communicating branch was found in 7 cases out of 14. CONCLUSION: The medial approach to the forearm gave access to all the muscular branches from the median and ulnar nerve to the flexor pollicis longus, flexor digitorum superficialis and flexor digitorum profundus, without extensive transmuscular dissection of the pronator teres or flexor digitorum superficialis muscles. This approach opens the way for selective neurectomy of the flexor pollicis longus, flexor digitorum profundus and flexor digitorum superficialis muscles. LEVEL OF EVIDENCE: IV.

Transfer of the palmaris brevis motor branch to the thenar motor branch: A cadaveric preliminary study.

OBJECTIVE: High median nerve injuries can lead to poor distal recovery, especially poor functioning of median innervated thenar muscles involved in thumb opposition and palmar abduction. The palmaris brevis (PB) is a small subcutaneous muscle innervated by ulnar nerve. Innervation of the PB is in most of cases provided by the ulnar digital nerve to the little finger. The purpose of this study is to assess the feasibility of transferring the PB motor branch (PBMB) to the median nerve thenar motor branch (TMB), in order to allow for early restoration of thumb palmar abduction and opposition, through a preliminary cadaveric study. METHODS: Twenty-five cadaver upper limbs were dissected under magnification. The length of the PBMB and TMB, and their origin were recorded. Nerve transfer from PBMB to TMB was conducted, and evaluated on 2 parameters: surgical feasibility, and distance from the coaptation site to the recipient nerve muscle entry point. The PBMB and TMB were harvested, fixated in formalin, then embedded in paraffin. They were sectioned transversely, and stained with a combination of hematoxylin-eosin and Luxol fast blue. Myelinated axons were counted in each specimen and the donor-to-recipient axon ratio was recorded. RESULTS: The PBMB was constant and originated from the ulnar digital nerve of the little finger in all cases. The transfer from PBMB to TMB was feasible in all cases. Mean myelinated axon counts of PBMB and TMB were 253±142 and 356±198, respectively (p=0.06). The donor-to-recipient axon ratio was 1:1.41. The mean distance from coaptation of the PBMB to the recipient thenar muscles was 23.1±3.0mm. CONCLUSIONS: Based on our results, PBMB to TMB transfer is feasible. The PBMB has the advantage over other distal nerve transfer donors to be constant and superficial, allowing for an easier harvest. Moreover, this procedure does not sacrifice any intrinsic function of the hand, and the proximity of the PBMB with the carpal tunnel allows for a single incision procedure. Therefore, early restoration of the median innervated thenar muscles may be feasible by the PBMB to TMB transfer in cases of high median nerve lesions. LEVEL OF EVIDENCE: IV.

A Retrospective Self-Controlled Study Evaluating the Prophylactic Effects of CACIPLIQ20 on Postsurgical Scars.

Background: CACIPLIQ20 (OTR3, Paris, France) is a medical device used for the treatment of chronic skin ulcers. It contains a heparan sulfate mimetic that accelerates tissue healing by stabilizing matrix proteins and protecting heparin-binding growth factors. In humans, an open self-controlled study suggested that the topical application of CACIPLIQ20 optimizes skin healing following surgery. Objectives: To expand previous findings using a different CACIPLIQ20 administration regimen. Methods: Twenty-four females were referred for breast-reduction surgery. Each patient had their own control with 1 CACIPLIQ20-treated and 1 saline-treated control breast. The treated side (right or left) was randomly assigned by the operating surgeon. Scar appearance was assessed by 6 independent raters using a global visual scar comparison scale based on scar photographs. All raters were blinded toward the CACIPLIQ20-treated side. Results: The follow-up period following surgery ranged from 1 to 12 months with a median follow-up of 6 months. Overall, there was a mean improvement of 15.2% (SD = 26.7) in favor of CACIPLIQ20 (P = .016). On the CACIPLIQ20-treated side, the mean score per patient was above 20% in 11 patients and above 30% improvement in 8 cases. In contrast, only 3 patients were considered improved by at least 20% on the control side and only 1 above 30%. A comparison of different application regimens suggested that the best trend was obtained with a single administration of CACIPLIQ20 at Day 0. Conclusions: In conclusion, CACIPLIQ20 could represent an interesting scar prophylactic therapy, based on a single administration at the time of surgery, and without any known adverse effects.

Anatomic Study of the Integrity of the Breast Lymphatic Network With Indocyanine Green in Breast Implant Surgery Through the Axillary Approach.

INTRODUCTION: The performance of a prosthetic breast augmentation through the axilla always makes the surgeon fear the possibility of damage to the breast lymphatic network. Indocyanine green is a fluorescent marker allowing the analysis of the lymphatic system. This anatomical work aims at demonstrating, thanks to the use of indocyanine green, whether the realization of a prosthetic breast augmentation by axillary way leads to lesions of the breast lymphatic network and also seeks to show the feasibility of detecting the axillary sentinel node after axillary breast augmentation. MATERIAL AND METHOD: This is an anatomical study. After injection of indocyanine green in the periareolar area, a prosthetic breast augmentation was performed through the axilla. At the end of the procedure, a change in the distribution of indocyanine green in the skin or its abnormal presence was sought: at the level of the skin incision, the prosthetic space, or in contact with the prosthesis itself. The presence of green in these situations was synonymous with a lesion of the lymphatic network. In the opposite case, we considered that the lymphatic system was respected. After sampling, an axillary lymph node we also looked for the presence of indocyanine green at its contact. RESULTS: We performed 22 breast injections. The lymphatic network could be demonstrated in 15 of them. Among these 15 injections, 12 (80%) were in favor of a preservation of the lymphatic network, whereas 3 (20%) evoked a lesion of the lymphatic network. In all subjects (100%), an axillary lymph node was found with the presence of indocyanine green within it. CONCLUSION: Our study is in favor of a preservation of the lymphatic network during a prosthetic breast augmentation by axillary way. Furthermore, with the collection of an axillary lymph node containing the dye from each subject, this work demonstrates the feasibility of axillary sentinel node detection with indocyanine green after axillary breast augmentation. Further work on live subjects and on a larger number of subjects would be necessary to confirm these results.

Management of Complex Forearm Injuries: Our Strategy of Reconstruction and Clinical Results.

ABSTRACT: The management of complex forearm injuries is challenging, not only because of the anatomical complexity of the region but also because of the dramatic functional consequences of these injuries. Preservation of the upper limb and restoration of hand function are the focus of the surgical management of these injuries. Decision making will consider several parameters such as the type of injury, the patient, the moment of reconstruction, the debridement, and the options available for reconstruction.A multidisciplinary approach joining plastic surgeons and orthopedic surgeons in a team effort is essential to achieve the best outcomes. On the basis of their experience, the authors conclude that the keystone in complex forearm injuries management is represented by a careful assessment of the lesions, an aggressive and early debridement, the prevention of complications such as infection and compartment syndrome, and an "as early as possible" reconstruction.

Feasibility of the abductor pollicis longus hemitendon transfer for thumb opposition: An anatomical study.

INTRODUCTION: The abductor pollicis longus (APL) presents two muscle bellies and multiple accessory tendons available for transfer, amongst these an accessory tendon inserting on the thenar aponeurosis (APLTh). Edgerton described an opponensplasty using the whole APL tendon, but its results were limited due to the short size of the donor tendon. HYPOTHESIS: The purpose of this study is to assess the feasibility of transferring the APLTh for thumb opposition. MATERIAL AND METHODS: Eleven cadaver upper limbs were dissected to assess the presence of the two heads of the APL as well as their main and accessory tendon insertions. The accessory tendon of the APL inserting on the thenar aponeurosis (APLTh) was harvested with a slip of the thenar aponeurosis. The length of the transplant, the number of tendon slips and their location, as well as pre and postoperative radial and palmar abduction provided by the APL were assessed. RESULTS: The APL was present in all cadavers whereas its insertion on the thenar aponeurosis was absent in 18% of the cases. When the APLTh was present and could be used for opponensplasty, the mean gain in palmar abduction was 16 degrees, and the mean loss in radial abduction was 21 degrees. DISCUSSION: Although the experiments revealed a variability in APL anatomy, when present, the APLTh represents a suitable donor for the restoration of thumb opposition. In some cases of high median nerve palsies, thumb opposition can't be restored using median innervated muscles. In these cases, when the APLTh is present, it can be used to restore thumb opposition without functional loss. LEVEL OF EVIDENCE: IV; anatomical feasibility study.

WALANT for hand wound exploration in isolated conditions: Feasibility study.

INTRODUCTION: Military doctors usually deal with hand wound management. Their practice sometimes takes them far from any specialized surgical center. The WALANT could be a powerful tool for doctors operating in nuclear submarines or as part of special forces. This is a comparative, prospective and multicenter study. The hypothesis was that the management of hand wounds by military doctors specifically trained in WALANT and in the surgical exploration of hand wounds allowed a diagnosis as effective as in the FESUM center. PATIENTS AND METHODS: Military doctors, usually operating in isolated conditions, were trained at WALANT. Then, this method was used for the exploration of hand wounds in the emergency room, in a center outside FESUM. At the end, two different questionnaires were completed respectively by the patient and the operator. They aimed to assess various criteria such as the overall satisfaction of the patient and the operator, the level of pain felt or the ability of the operator to establish a precise lesion assessment. The results were compared with those obtained under the same conditions by hand surgeons in the FESUM centre. RESULTS: No significant difference was found between the two centers in terms of diagnostic capacity, satisfaction, comfort and perceived pain intensity. DISCUSSION: Under cover of prior training, the WALANT is effective for the exploration of hand wounds by submariner doctors and members of the special forces. Its use makes it possible to establish a precise injury report and this in material and human conditions approaching as closely as possible those of the armed forces on mission. The comfort of the patient remains preserved. CONCLUSION: The WALANT represents an effective tool for the exploration and lesion assessment of hand wounds outside the FESUM centre. Since emergency conditions are similar to those encountered in operational conditions, its use is also possible in situations specific to military doctors: nuclear submarines, special forces on mission. LEVEL OF EVIDENCE: III; comparative study, retrospective, multicentre.

Hyperselective neurectomy for the treatment of upper limb spasticity in adults and children: a prospective study.

Hyperselective neurectomy (HSN) procedures in the spastic upper limb aim to reduce tone by excising some branches of the involved peripheral motor nerves, at the point of entry of each motor ramus into the target muscle. In this prospective study, 42 patients with upper limb spasticity were treated by HSN for the muscles of elbow flexion, forearm pronation and wrist flexion and evaluated for their short-term results (average 6 months) and long-term outcomes (average 31 months). Results at both time points showed an effective reduction of the spastic tone, with no decrease of muscle strength in the operated spastic muscles. Comparison of results between the two time points showed durability of the improvement, which remained statistically significant despite a slight relapse in spasticity. The results of HSN compare favourably with the other techniques of partial neurectomy; however, the technique requires a detailed knowledge of upper limb motor anatomy.Level of evidence: II.

Four-arm robotic lung resection versus muscle-sparing mini-thoracotomy: retrospective experience.

BACKGROUND: Robotic surgery was introduced in the early 2000s but its use remains limited, particularly in thoracic surgery. Here we compare the first consecutive 185 four-arm robotic procedures carried out in our institution vs. muscle-sparing video-assisted mini-thoracotomy (MSMT), our previous minimally invasive approach for anatomical lung resection. METHODS: One hundred and eighty-five consecutive patients undergoing surgery using the four-arm robotic technique between February 2014 and December 2016 were compared to a control historical series of 136 consecutive patients undergoing surgery by MSMT in the same institution. The same senior surgeon performed all surgical procedures. Comparisons between the two groups were performed using the Chi2 test for qualitative data and the Wilcoxon, Mann-Whitney or Student's t-test for quantitative data. RESULTS: The demographic and clinical characteristics of the patients were similar in the two groups. In the robotic group, median (min-max) length of hospital stay (LOS) was significantly shorter (by 2 days) than in the MSMT group {7 days [3-63] vs. 9 days [5-63], respectively; P<0.0001}. The rate of complications was similar in the two groups, but the complications appeared to be less severe in patients undergoing robotic surgery (switch from Clavien-Dindo grade III and IV to grade II) although further studies are required to confirm this due to the large number of missing data. CONCLUSIONS: In a senior thoracic surgery practice, the switch from a minimally invasive technique to robotic surgery was safe and beneficial in patients undergoing anatomical lung resection in terms of LOS and possible complication severity.

Combining population genomics and forward simulations to investigate stocking impacts: A case study of Muskellunge (Esox masquinongy) from the St. Lawrence River basin.

Understanding the genetic and evolutionary impacts of stocking on wild fish populations has long been of interest as negative consequences such as reduced fitness and loss of genetic diversity are commonly reported outcomes. In an attempt to sustain a fishery, managers implemented nearly five decades of extensive stocking of over a million Muskellunge (Esox masquinongy), a native species in the Lower St. Lawrence River (Québec, Canada). We investigated the effect of this stocking on population genetic structure and allelic diversity in the St. Lawrence River in addition to tributaries and several stocked inland lakes. Using genotype by sequencing, we genotyped 643 individuals representing 22 locations and combined this information with forward simulations to investigate the genetic consequences of long-term stocking. Individuals native to the St. Lawrence watershed were genetically differentiated from stocking sources and tributaries, and inland lakes were naturally differentiated from the main river. Empirical data and simulations within the St. Lawrence River revealed weak stocking effects on admixture patterns. Our data suggest that the genetic structure associated with stocked fish was diluted into its relatively large effective population size. This interpretation is also consistent with a hypothesis that selection against introgression was in operation and relatively efficient within the large St. Lawrence River system. In contrast, smaller populations from adjacent tributaries and lakes displayed greater stocking-related admixture that resulted in comparatively higher heterozygosity than the St. Lawrence. Finally, individuals from inland lakes that were established by stocking maintained a close affinity with their source populations. This study illustrated a benefit of combining extensive genomic data with forward simulations for improved inference regarding population-level genetic effects of long-term stocking, and its relevance for fishery management decision making.