Rapid and Precise Semi-Automatic Axon Quantification in Human Peripheral Nerves

We developed a time-efficient semi-automated axon quantification method using freeware in human cranial nerve sections stained with paraphenylenediamine (PPD). It was used to analyze a total of 1238 facial and masseteric nerve biopsies. The technique was validated by comparing manual and semi-automated quantification of 129 (10.4%) randomly selected biopsies. The software-based method demonstrated a sensitivity of 94% and a specificity of 87%. Semi-automatic axon counting was significantly faster (p<0.001) than manual counting. It took 1hour and 47minutes for all 129 biopsies (averaging 50sec per biopsy, 0.04seconds per axon). The counting process is automatic and does not need to be supervised. Manual counting took 21hours and 6minutes in total (average 9minutes and 49seconds per biopsy, 0.52seconds per axon). Our method showed a linear correlation to the manual counts (R=0.944 Spearman rho). Attempts have been made by several research groups to automate axonal load quantification. These methods often require specific hard- and software and are therefore only accessible to a few specialized laboratories. Our semi-automated axon quantification is precise, reliable and time-sparing using publicly available software and should be useful for an effective axon quantification in various human peripheral nerves

Histomorphometry of the Sural Nerve for Use as a CFNG in Facial Reanimation Procedures

Facial palsy (FP) is a debilitating nerve pathology. Cross Face Nerve Grafting (CFNG) describes a surgical technique that uses nerve grafts to reanimate the paralyzed face. The sural nerve has been shown to be a reliable nerve graft with little donor side morbidity. Therefore, we aimed to investigate the microanatomy of the sural nerve. Biopsies were obtained from 15 FP patients who underwent CFNG using sural nerve grafts. Histological cross-sections were fixated, stained with PPD, and digitized. Histomorphometry and a validated software-based axon quantification were conducted. The median age of the operated patients was 37 years (5–62 years). There was a significant difference in axonal capacity decrease towards the periphery when comparing proximal vs. distal biopsies (p = 0.047), while the side of nerve harvest showed no significant differences in nerve caliber (proximal p = 0.253, distal p = 0.506) and axonal capacity for proximal and distal biopsies (proximal p = 0.414, distal p = 0.922). Age did not correlate with axonal capacity (proximal: R = −0.201, p = 0.603; distal: R = 0.317, p = 0.292). These novel insights into the microanatomy of the sural nerve may help refine CFNG techniques and individualize FP patient treatment plans, ultimately improving overall patient outcomes

Verzicht auf Drainagen bei der Abdominoplastik – eine randomisiert-kontrollierte Studie

Introduction There is insufficient scientific evidence from randomised controlled trials to support the routine use of closed-suction drains in body contouring procedures. The aim of this study was to evaluate cumulative seroma volume, length of hospital stay and complication rates in abdominoplasty patients without drains in direct comparison with a cohort receiving drains. Material and Methods Abdominoplasty patients were prospectively randomised in two study groups with (MD) and without (OD) placement of closed-suction drains. Patients with a BMI = 3. Cumulative seroma volume over a four-week follow-up period was assessed as the primary outcome measure. Secondary outcome measures were complications requiring surgical revision and length of hospital stay. Results This trial did not identify a statistically significant difference in cumulative seroma volume between the MD (30/53) and OD (23/53) cohorts in 53 patients (M(MD)493 +/- SD 407 ml; M(OD)459 +/- SD 624 ml; p = 0.812). However, a significantly shorter average length of hospital stay was observed in the OD population (M(MD)5.1 +/- SD 1.4 d; M(OD)4.2 +/- SD 1.5 d; p = 0.023). Complication rates were equal in both study groups (n(MD) = 1; n(OD) = 1). Conclusion The results of this trial do not justify routine placement of closed-suction drains in abdominoplasty procedures (horizontal or combined horizontal/vertical incision) in the pre-obese patient cohort (BMI <= 30 kg/m(2)). Drain placement should be evaluated on an individual patient-specific basis

Standard doses of Triamcinolone do not affect fibroblast cell migration of abdominoplasty patients in-vitro1

BACKGROUND:Recent studies have demonstrated that local application of corticosteroids reduces wound exudation following abdominoplasty and other reconstructive surgical procedures. On the other hand, corticosteroids might provoke wound healing disturbances due to their immunosuppressive effects. OBJECTIVE:The main objective of this study was to gain further information about the impact of the corticosteroid triamcinolone on cell migration in abdominoplasty patients. METHODS:An in-vitro scratch assay wound healing model was applied to observe cell migration of fibroblasts cultured with nutrient medium containing human seroma aspirate±triamcinolone. RESULTS:There were no significant differences regarding cell migration when fibroblasts were incubated with triamcinolone + seroma containing culture medium compared to seroma containing culture medium without triamcinolone. CONCLUSIONS:The performed in-vitro study suggests that triamcinolone does not decelerate fibroblast cell migration which is considered as a surrogate of wound healing

Clinical Impact of DIEP Flap Perforator Characteristics – A Prospective Indocyanine Green Fluorescence Imaging Study

Background: The question to what extent perfusion in deep inferior epigastric perforator (DIEP) flaps depends on specific perforator characteristics has been raised. Anatomical studies and previous clinical trials focussing on DIEP flap perfusion resulted in discrepancies. This prospective study investigates how perforator row, number and diameter affect DIEP flap microperfusion via Indocyanine Green (ICG) fluorescence angiography. Methods: The fractional weight of insufficiently perfused flap tissue in Zone 4 related to the total DIEP flap weight was measured based on ICG fluorescence angiography and defined as Zone 4 %. As a surrogate for overall DIEP flap perfusion, Zone 4 % was assessed according to the row, number and diameter of perforators included in the flap. Results: In 42 unilateral DIEP flap breast reconstructions, neither medial (33.6 +/- 14.2 %)/lateral perforator row (29.9 +/- 7.5 %, p = 0.683) nor the parameter perforator number (single perforator 31.5 +/- 14.4 %, two perforators 30.2 +/- 10.2 %, p = 0.727) had a statistically significant effect on flap tissue availability as measured via Zone 4 %. A negative correlative trend between perforator diameter and Zone 4 % (r = -0.096, p = 0.588) was observed. Conclusion: Zone 4 % provides a novel method for an objective assessment of DIEP flap perfusion. Medial/lateral row selection and other perforator properties (number, diameter) within the standard ranges, did not affect Zone 4 % as indicated by ICG fluorescence angiography. (C) 2020 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved

“A-PePSI LIGhT” Assessment Score to Predict Pressure Sore Impaired Healing Late Recurrence, Immobility, Greater Surface, Inhibited Thrombocytes

Background: Complication rates of up to 46 percent are reported following pressure sore surgery. Pressure sore patients often exhibit ineffective postoperative wound healing despite tension-free flap coverage, necessitating surgical revision and prolonged hospitalization. Rather than pressure sore recurrence, such impaired healing reflects a failed progress through the physiologic stages of the normal wound-healing cascade. The principal objective of the study reported here was to elucidate potentially modifiable inherent variables that predict predisposition to impaired healing and to provide a tool for identifying cases at risk for complicated early postoperative recovery following pressure sore reconstruction. Methods: A retrospective chart review of late-stage (stage 3 or higher) sacral and ischial pressure sore patients who underwent flap reconstruction from 2014 to 2019 was performed. A multivariable logistic regression model was used to identify key patient and operative factors predictive of impaired healing. Furthermore, the Assessment Score to Predict Pressure Sore Impaired Healing (A-PePSI) was established based on the identified risk factors. Results: In a cohort of 121 patients, 36 percent exhibited impaired healing. Of these, 34 patients suffered from dehiscences, necessitating surgical revision. Statistically significant risk factors comprising late recurrence (OR, 3.8), immobility (OR, 12.4), greater surface (>5 cm diameter; OR, 7.3), and inhibited thrombocytes (aspirin monotherapy; OR, 5.7) were combined to formulate a prognostic scoring system (A-PePSI LIGhT). Conclusions: The A-PePSI LIGhT score serves as a prognostic instrument for assessing individual risk for impaired healing in pressure sore patients. Preoperative risk stratification supports rational decision-making regarding operative candidacy, allows evidence-based patient counseling, and supports the implementation of individualized treatment protocols

Perfusion maintains functional potential in denervated mimic muscles in early persistent facial paralysis which requires early microsurgical treatment – the histoanatomic basis of the extratemporal facial nerve trunk assessing axonal load in the context of possible nerve transfers1

BACKGROUND AND OBJECTIVES: Early persistent facial paralysis is characterized by intact muscles of facial expression through maintained perfusion but lacking nerve supply. In facial reanimation procedures aiming at restoration of facial tone and dynamics, neurotization through a donor nerve is performed. Critical for reanimating target muscles is axonal capacity of both donor and recipient nerves. In cases of complete paralysis, the proximal stump of the extratemporal facial nerve trunk may be selected as a recipient site for coaptation. To further clarify the histological basis of this facial reanimation procedure we conducted a human cadaver study examining macro and micro anatomical features of the facial nerve trunk including its axonal capacity in human cadavers. Axonal loads, morphology and morbidity of different donor nerves are discussed reviewing literature in context of nerve transfers. METHODS: From 6/2015 to 9/2016 in a group of 53 fresh frozen cadavers a total of 106 facial halves were dissected. Biopsies of the extratemporal facial nerve trunk (FN) were obtained at 1 cm distal to the stylomastoid foramen. After histological processing and digitalization of 99 specimens available, 97 were selected eligible for fascicle counts and 87 fulfilled quality criteria for a semi-automated computer-based axon quantification software using ImageJ/Fiji. RESULTS: An average of 3.82 fascicles (range, 1 to 9) were noted (n = 97). 6684 +/- 1884 axons (range, 2655-12457) were counted for the entire group (n = 87). Right facial halves showed 6364 +/- 1904 axons (n = 43). Left facial halves demonstrated 6996 +/- 1833 axons (n = 44) with no significant difference (p = 0.73). Female cadavers featured 6247 +/- 2230 (n = 22), male showed 6769 +/- 1809 axons (n= 40). No statistical difference was seen between genders (p = 0.59). A comparison with different studies in literature is made. The nerve diameter in 82 of our specimens could be measured at 1933 +/- 424 mu m (range, 975 to 3012). CONCLUSIONS: No donor nerve has been described to match axonal load or fascicle number of the extratemporal facial nerve main trunk. However, the masseteric nerve may be coapted for neurotization of facial muscles with a low complication rate and good clinical outcomes. Nerve transfer is indicated from 6 months after onset of facial paralysis if no recovery of facial nerve function is seen

Microanatomy of the Frontal Branch of the Facial Nerve: The Role of Nerve Caliber and Axonal Capacity

Background: A commonly seen issue in facial palsy patients is brow ptosis caused by paralysis of the frontalis muscle powered by the frontal branch of the facial nerve. Predominantly, static methods are used for correction. Functional restoration concepts include the transfer of the deep temporal branch of the trigeminal nerve and cross-facial nerve grafts. Both techniques can neurotize the original mimic muscles in early cases or power muscle transplants in late cases. Because axonal capacity is particularly important in cross-facial nerve graft procedures, the authors investigated the microanatomical features of the frontal branch to provide the basis for its potential use and to ease intraoperative donor nerve selection. Methods: Nerve biopsy specimens from 106 fresh-frozen cadaver facial halves were obtained. Histologic processing and digitalization were followed by nerve morphometric analysis and semiautomated axon quantification. Results: The frontal branch showed a median of three fascicles (n = 100; range, one to nine fascicles). A mean axonal capacity of 1191 +/- 668 axons (range, 186 to 3539 axons; n = 88) and an average cross-sectional diameter of 1.01 +/- 0.26 mm (range, 0.43 to 1.74 mm; n = 67) were noted. In the linear regression model, diameter and axonal capacity demonstrated a positive relation (n = 57; r(2) = 0.32; p < 0.001). Based on that equation, a nerve measuring 1 mm is expected to carry 1339 axons. Conclusion: The authors' analysis on the microanatomy of the frontal branch could promote clinical use of cross-facial nerve graft procedures in frontalis muscle neurotization and free muscle transplantations