Heme oxygenase-1 therapy attenuates muscle atrophy following global brachial plexus avulsion in juvenile rats.

INTRODUCTION/AIMS: Brachial plexus injury can seriously affect distal target muscle function, and long-term denervation leads to irreversible structural damage. In the present study, we examined the effect of hemin, a heme oxygenase-1 (HO-1) inducer, on intrinsic forepaw muscle atrophy induced by pan-plexus injury in juvenile rats, as well as its underlying mechanism. METHODS: A global brachial plexus avulsion (GBPA) model of rat was established, and thirty 6-wk-old male rats were randomly divided into five groups: control, GBPA plus scramble small intering RNA (siRNA), GBPA plus scramble siRNA plus hemin, GBPA plus HO-1 siRNA, and GBPA plus HO-1 siRNA plus hemin. Hemin (50 mg/kg) was administered intraperitoneally once daily and the siRNA (5 µg) was injected intramuscularly twice a week. Intrinsic forepaw muscles were used for analysis. Myofiber cross-sectional area (CSA), capillary-to-fiber ratio (C/F), and fiber-type composition were assessed. The levels of inflammatory factors, ubiquitin-protein ligases, and autophagy-related proteins were also measured. RESULTS: We found that hemin treatment could effectively ameliorate denervated intrinsic forepaw muscle atrophy and suppress type I to II myofiber-type conversion. Hemin treatment failed to prevent muscle capillary loss after denervation. The levels of inflammatory factors (tumor necrosis factor alpha [TNFα] and interleukin 6 [IL-6]), ubiquitin-protein ligases (MuRF-1 and MAFbx), and autophagy-related proteins (BNIP3 and LC3B-II/I ratio) were increased by denervation and HO-1 therapy attenuated the increment. DISCUSSION: Upregulation of HO-1 might potentially be an effective strategy to alleviate denervation-related muscle atrophy and might be a promising adjunctive treatment to improve hand function in children with pan-plexus injury.

Restoration of intrinsic hand function by superficial radial nerve: an anatomical study.

BACKGROUND: The contralateral seventh cervical (cC7) nerve root transfer represents a cornerstone technique in treating total brachial plexus avulsion injury. Traditional cC7 procedures employ the entire ulnar nerve as a graft, which inevitably compromises its restorative capacity. OBJECTIVE: Our cadaveric study seeks to assess this innovative approach aimed at preserving the motor branch of the ulnar nerve (MBUN). This new method aims to enable future repair stages, using the superficial radial nerve (SRN) as a bridge connecting cC7 and MBUN. METHODS: We undertook a comprehensive dissection of ten adult cadavers, generously provided by the Department of Anatomy, Histology, and Embryology at Fudan University, China. It allowed us to evaluate the feasibility of our proposed technique. For this study, we harvested only the dorsal and superficial branches of the ulnar nerve, as well as the SRN, to establish connections between the cC7 nerve and recipient nerves (both the median nerve and MBUN). We meticulously dissected the SRN and the motor and sensory branches of the ulnar nerve. Measurements were made from the reverse point of the SRN to the wrist flexion crease and the coaptation point of the SRN and MBUN. Additionally, we traced the MBUN from distal to proximal ends, recording its maximum length. We also measured the diameters of the nerve branches and tallied the number of axons. RESULTS: Our modified approach proved technically viable in all examined limbs. The distances from the reverse point of the SRN to the wrist flexion crease were 8.24 ± 1.80 cm and to the coaptation point were 6.60 ± 1.75 cm. The maximum length of the MBUN was 7.62 ± 1.03 cm. The average axon diameters in the MBUN and the anterior and posterior branches of the SRN were 1.88 ± 0.42 mm、1.56 ± 0.38 mm、2.02 ± 0.41 mm,respectively. The corresponding mean numbers of axons were 1426.60 ± 331.39 and 721.50 ± 138.22, and 741.90 ± 171.34, respectively. CONCLUSION: The SRN demonstrated the potential to be transferred to the MBUN without necessitating a nerve graft. A potential advantage of this modification is preserving the MBUN's recovery potential.

Microarray analysis of potential biomarkers of brachial plexus avulsion caused neuropathic pain in male rat.

The present study aimed to investigate the expression of mRNA in the brachial plexus avulsion neuropathic pain model and analyze biological functions. Microarray mRNA assay and reverse transcriptase quantitative polymerase chain reaction (RT-PCR) were conducted. The whole blood was collected from two groups for Microarray mRNA analysis. The predicted mRNA targets were studied by gene ontology analysis and pathway analysis. We identified 3 targeted mRNAs, including PIK3CB, HRAS, and JUN. The results showed that PIK3CB, HRAS, and JUN gene expression was increased in the control group but decreased in the neuropathic pain group. These findings indicate that certain genes may be important biomarkers for the potential targets for the prevention and treatment of brachial plexus avulsion caused neuropathic pain.

Resection and reconstruction for radial polydactyly Type IV-D in 206 cases: a retrospective clinical analysis.

BACKGROUND: Radial Polydactyly Type IV-D deformity is difficult to treat because of the most complex bone and soft tissue anomalies. Resection and reconstruction for one of the two thumbs was an option for treatment. OBJECTIVE: The study was to present our method of resection and reconstruction with a new incision for radial polydactyly Type IV-D and evaluate the clinical efficacy comprehensively using Rotterdam assessment system in a large sample. METHODS: 206 cases of type IV-D thumb duplication underwent resection and reconstruction surgical treatment between 2010 and 2019. Two equal triangle flap incisions were designed around the radial thumb. The radial thumb was resected and the ulnar thumb was reconstructed in aspects of bone, tendons, ligaments and abductor pollicis brevis. The clinical results were evaluated using Rotterdam assessment system. RESULTS: The mean follow-up period was 2.2 years (SD 1.5). The mean age of the patients was 9 months (SD 1.8) at the time of operation. The mean ranges of active IP and MP joint flexion and extension were 110° and 26°. The mean angulations for IP and MP joint instabilities were 3° and 11°, relatively. Angulation for palmar abduction was 58°. The mean appearance domain score was 8.9. The average parental satisfaction score was 2.5 and the average patient-reported pain score was 2.1. The mean functional domain score for all patients was 6.6. The average appearance domain score was 8.9. The mean patient-reported domain score was 4.5. The mean Rotterdam outcome score was 20.0, equivalent to 67% of the full score. The postoperative score of patients over two years old was significantly lower than that of patients under two years old. CONCLUSION: Resection and reconstruction method with two equal triangle flap incisions was a recommended treatment for radial polydactyly Type IV-D. LEVEL OF EVIDENCE: IV.

Why It Is Necessary to Use the Entire Root rather than Partial Root When Doing Contralateral C7 Nerve Transfer: Cortical Plasticity Also Matters besides the Amount of Nerve Fibers.

Previous studies suggested that the mode of donor transection is a critical factor affecting the efficacy of the contralateral C7 (CC7) nerve transfer. Nevertheless, the mechanism underlying this phenomenon remains elusive. The aim of this study was to investigate the relationship between the division modes of the CC7 nerve and cortical functional reorganization of Sprague-Dawley rats. We hypothesized that different methods of CC7 nerve transection might induce differences in cortical functional reorganization, thus resulting in differences in surgery efficacy. BDNF, TNF-α/IL-6, and miR-132/134 were selected as indicators of cortical functional reorganization. No significant differences in all these indicators were noted between the entire group and the entire root+posterior division group (P > 0.05). BDNF and miR-132/134 levels in the entire group and the entire root+posterior division group were significantly increased compared with their levels in the posterior group and the blank control group (P < 0.001). In all groups, BDNF, TNF-α/IL-6, and miR-132/134 levels in both hemispheres initially increased and subsequently decreased until week 40. In conclusion, this study provided the evidence of dynamic changes in BDNF, TNF-α/IL-6, and miR-132/134 in the cortex of rats after CC7 nerve transfer using different transecting modes, demonstrating that different CC7 nerve divisions might result in different surgical effects through modulation of cortical reorganization.

Green Tea Polyphenols Promote Functional Recovery from Peripheral Nerve Injury in Rats.

BACKGROUND Peripheral nerve injury (PNI) is a common and progressive disorder with sensory and motor deficits in the peripheral nervous system (PNS). Treatment is difficult, with unfavorable prognosis. Green tea polyphenols (GTPs) exert neuroprotective effects on regeneration of the central nervous system (CNS). However, the effects of GTPs on functional recovery of the PNS have not been fully characterized. Consequently, the present study investigated the effects of GTPs on nerve regeneration of rats with PNI. MATERIAL AND METHODS The model of PNI was established in rats by sciatic nerve injury (SNI). Adult male Wistar rats with SNI were randomly divided into a vehicle group and a GTPs group. The compound muscle action potential (CMAP) of rat sciatic nerves (SN) was measured using the CM6240 physiological signal acquisition and processing system. The wet weight of the triceps muscle was determined using an analytical balance. The number of myelinated nerve fibers was counted under an optical microscope. Ultrastructure of the regenerated nerves in SN was observed by transmission electron microscopy. The mRNA and protein expression of nerve growth factor (NGF), growth-associated protein-43 (GAP-43), neurofilament 200 (NF200), and myelin-associated glycoprotein (MAG) in SN stumps were measured by real-time quantification PCR (RT-qPCR) and Western blot, respectively. RESULTS In rats with SNI, GTPs relieved the adhesion between nerve anastomosis and surrounding tissues, and significantly increased nerve conduction velocity, wet weight of the triceps muscle, and development and axonal regeneration of myelinated nerve fibers. Moreover, GTPs promoted the mRNA and protein expressions of NGF, GAP-43, NF200, and MAG in SN stumps. CONCLUSIONS GTPs promotes nerve regeneration in rats with SNI.

Contralateral C7 transfer to axillary and median nerves in rats with total brachial plexus avulsion.

BACKGROUND: Contralateral cervical 7 nerve (cC7) was used to repair two recipient nerves simultaneously for patients with total brachial plexus avulsion (TBPA). OBJECTIVE: To evaluate the effect of cC7 transfer to axillary and median nerves in rats with TBPA. METHODS: Eighty S-D rats were divided into 4 groups randomly on average. Group A: cC7-median nerve, Group B: cC7-axillary nerve, Group C: cC7-median and axillary nerves, Group D: TBPA without repair. The evaluation tools included behavioral tests, electromyogram (EMG), measurement of cross-sectional area of muscle fiber, nerve fiber count and gene expression assay. RESULTS: The effective rates of EMG were 90 and 70% in Flexor Carpi Radialis (FCR) in Group A and C, while 70 and 60% in deltoid (DEL) in Group B and C, respectively. In behavioral test, the differences of effective rates between groups were not significant. The mean cross-sectional area of FCR in Group A or C was significantly larger than that in Group D. Either the number of median or axillary nerve fibers in Group A, B or C was statistically more than that in Group D. No matter for FCR or DEL, there were no significant differences in the ratios of relative expression of Muscle Atrophy F-box(MAFBOX)and Muscle RING Finger 1(MURF1)among these groups. CONCLUSION: Compared with cC7 transfer to median nerve, cC7 transfer to both median and axillary nerves did not affect median nerve recovery. The deltoid muscle also could be restored. The recovery proportion of axillary nerve was less than that of median nerve.

Comparative Study of Intercostal Nerve and Contralateral C7 Nerve Transfers for Elbow Extension After Global Brachial Plexus Avulsion.

INTRODUCTION: Elbow extensive reconstruction was essential for the patients with brachial plexus avulsion. Nerve transfer was applied to repair elbow extension, but the ultimate recovery was quite different. The purpose of this study was to compare the effects of elbow extension in patients with global brachial plexus avulsion after repaired by intercostal nerve (ICN) and contralateral cervical 7 (cC7) nerve transfer to the long head branch of triceps and to analyze the possible influencing factors. MATERIALS AND METHODS: A retrospective review of 24 patients treated with ICN and cC7 nerve transfer for elbow extension in posttraumatic global brachial plexus avulsion was carried out. Two ICNs were used as donors in 17 patients, and cC7 nerve was used in the other 7 patients. We evaluated the recovery of elbow extension by the British Medical Research Council grading system and electromyography. The correlation between age, preoperative interval, and prognosis was analyzed in this study. RESULTS: Efficiency of elbow extensor strength in the ICN transfer group was 47.06%, and it was 28.57% in the cC7 nerve transfer group, but there was no significant difference (P = 0.653). The effective recovery of electromyography in ICN transfer group was 82.35%, whereas in the group cC7 nerve transfer, it was 28.57%, there was a statistical difference between the 2 groups (P = 0.021). Age and interval were negatively correlated with prognosis. CONCLUSIONS: Intercostal nerve or cC7 nerve transfer to the long head branch of triceps could reconstruct elbow extension to some extent. Compared with cC7 nerve transfer, ICN transfer had a greater result for elbow extension, but the difference in extension power was not significant, whereas there was difference in electromyography recovery. Patient's age and interval were negatively correlated with the results.

Comparative study of single and dual nerve transfers for repairing shoulder abduction.

OBJECTIVE: The purpose of this study was to compare the effects of single and dual nerve transfer for the repair of shoulder abduction in patients with upper or upper and middle trunk root avulsion. METHODS: We carried out a retrospective analysis of 20 patients with C5-C6 or C5-C7 root avulsion treated by nerve transfer in our hospital. The patients were divided into two groups according to the different operation methods. In group A, ten patients had transferred the spinal accessory nerve to the suprascapular nerve. Ten patients in group B underwent dual nerve transfer to reconstruct shoulder abduction, including the spinal accessory nerve transfer to the suprascapular nerve and two intercostal nerves or the long head of triceps nerve branch transfer to the anterior branch of the axillary nerve. There was no difference in age, preoperative interval, follow-up time, and injury type between the two groups. We used shoulder abduction strength, shoulder abduction angle, and Samardzic's shoulder joint evaluation standard as the postoperative evaluation index. Shoulder abductor muscle strength equals or above M3 was considered to be an effective recovery. RESULTS: Of the 20 cases, 15 obtained equals or more M3 of shoulder abduction strength, and the overall effective rate was 75%. The effective rate of shoulder abduction power in group A was 60% (6/10) while group B was 90% (9/10); however, the difference was not statistically significant (p > 0.05). The average shoulder abduction angle was 55° (SD = 19.29) in group A and 77° (SD = 20.44) in group B; the angle was significantly better in group B than that in group A (p < 0.05). Based on Samardzic's standard, the excellent and good rate of group A was 90% and in group B was 50%. The difference was statistically significant (p < 0.05). CONCLUSION: For patients with nerve root avulsion of C5-C6 or C5-C7, repairing suprascapular nerve and axillary nerve at the same time is more effective than repairing suprascapular nerve alone in terms of shoulder abduction angle and excellent rate of functional recovery of the shoulder joint. Therefore, we recommend the repair of the suprascapular nerve and the axillary nerve simultaneously if conditions permit.

The phrenic nerve transfer in the treatment of a septuagenarian with brachial plexus avulsion injury: a case report.

Phrenic nerve transfer has been a well-established procedure for restoring elbow flexion function in patients with brachial plexus avulsion injury. Concerning about probably detrimental respiratory effects brought by the operation, however, stirred up quite a bit of controversy. We present a case report of the successful application of phrenic nerve as donor to reinnervate the biceps in a septuagenarian with brachial plexus avulsion injury, not accompanied with significant clinical respiratory problem.

Restoration of ulnar nerve motor function by pronator quadratus motor branch: an anatomical study.

BACKGROUND: The traditional surgical approach to repair of brachial plexus lesions involves use of whole segment ulnar nerve graft for contralateral seventh cervical (cC7) nerve root transfer, which sabotages the possibility of ulnar nerve recovery. We assessed the anatomical feasibility of a new approach that involves preservation of the motor branch of ulnar nerve (MBUN), for a later stage repair using the recovered pronator quadratus motor branch (PQMB), subsequent to the cC7 transfer procedure. METHODS: Twenty-seven adult cadaver arms and one side of fresh adult cadaver were used in this study. The anterior interosseous nerve and its PQMB, as well as the motor and sensory branches of the ulnar nerve were dissected. The distances from the end of PQMB to the mid-point of a line joining the radial styloid and ulnar styloid, as well as to the point of divergence of the ulnar nerve, were measured. The MBUN was dissected from distal to proximal and the maximum length was measured. The diameter and number of axons of the nerve branches were also recorded. RESULTS: The distance from the end of the PQMB to the midpoint of the radial styloid and ulnar styloid was 6.04 ± 0.52 cm, and that to the point of divergence of the ulnar nerve was 8.02 ± 0.63 cm. The maximum length of the MBUN after its dissociation was 9.70 ± 1.38 cm. The mean diameters of axons of the MBUN and PQMB were 0.09 ± 0.02 cm and 0.05 ± 0.01 cm, respectively. The corresponding mean numbers of axons were 2913 ± 624 and 757 ± 183, respectively. CONCLUSIONS: The results indicate that the PQMB is suitable for transferring to the MBUN without nerve graft. This anatomical study paves the way for further testing of this new procedure after cC7 transfer in clinical settings.

Anatomical study of anterior supramalleolar artery and its potential application to design a bi-foliate fasciocutaneous flap.

PURPOSE: A further understanding of the anterior supramalleolar artery (ASMA) and its potential applications in reconstructive surgery. MATERIALS AND METHODS: A total of 24 fresh lower limbs from fresh cadavers were injected with red latex for dissection. The type of origin, course, diameter of the pedicle, and the distance between the origin of the ASMA from the anterior tibial artery to the extensor retinaculum (O-R) were recorded. Bi-foliate fasciocutaneous flaps were harvested using the branches of the ASMA. RESULTS: We found four types of origin of the ASMA, and we have accordingly classified them into four types. 10 of them were type A, 7 were type B, 6 were type C and 1 was type D. The mean O-R (origin of ASMA to retinaculum) distance was 2.0 ± 0.8 cm. The diameter of the medial branch (D1), the diameter of the lateral branch (D2), and the diameter of artery stem (D3) (only in type A) were 1.0 ± 0.2 mm, 0.8 ± 0.3 mm, 1.1 ± 0.2 mm, respectively. The mean pedicle length of the lateral flap (L1) and medial flap (L2) were 5.1 ± 1.0 cm and 3.7 ± 0.6 cm, respectively. CONCLUSIONS: The ASMA exists constantly with four different types of origin. Its sizable diameter and lengthy pedicle make it suitable for bi-foliate fasciocutaneous flap transfer.

Intercostal nerve transfer to neurotize the musculocutaneous nerve after traumatic brachial plexus avulsion: a comparison of two, three, and four nerve transfers.

The purpose of this study was to compare the outcomes of different numbers of intercostal nerve (ICN) transfers for elbow flexion and to determine whether age, body mass index (BMI), type of injury, and preoperative delay influence the outcomes. From 2004 to 2010, 32 (30 included) consecutive patients underwent ICN transfer to the musculocutaneous nerve following brachial plexus injury. Elbow flexion strength was evaluated according to the British Medical Research Council (BMRC) grading system. Of nine patients who received two ICN transfers, six (66.7%) recovered with useful elbow flexion compared with 14 of 17 (82.4%) patients who received three ICN transfers. Of the four patients with four ICN transfers, three (75%) achieved useful recovery. Statistical analysis showed no significant difference. There is no significant difference among the outcomes of two, three, and four ICN transfers to the musculocutaneous nerve. Two ICN transfers are sufficient for useful recovery of elbow flexion. Younger patients achieve better results.

An alternative method to reconstruct grade-3 hypoplastic thumb by hemi-metacarpal transfer.

We designed a new method using hemi-longitudinal second metacarpal bone to reconstruct grade-3 hypoplastic thumbs. Seven patients were treated in two stages. In the first stage, the second metacarpal was split longitudinally and transferred to reconstruct the first metacarpal. In the second stage, opponensplasty was performed by transferring the FDS tendon. Bone union was achieved in all cases. All patients could oppose to their middle finger at least. They managed to do daily activities such as writing, eating, using smartphones and so on. This is a useful procedure to preserve a 5-digit hand with good function in treating grade-3 hypoplastic thumbs, with no harm to the foot and no need for vascular anastomosis. LEVEL OF EVIDENCE: IV.

5-HT3a receptor contributes to neuropathic pain by regulating central sensitization in a rat with brachial plexus avulsion.

PURPOSE: As a frequently occurring complication resulting from brachial plexus avulsion (BPA), neuropathic pain significantly impacts the quality of life of patients and places a substantial burden on their families. Recent reports have suggested that the 5-HT3a receptor may play a role in the development and regulation of neuropathic pain. The current study aimed to explore the involvement of the 5-HT3a receptor in neuropathic pain resulting from BPA in rats. METHODS: A rat model of neuropathic pain was induced through brachial plexus avulsion (BPA). The pain thresholds of the rats were measured after BPA. The spinal dorsal horn (SDH) of rats was collected at day 14 after surgery, and the expression and distribution of the 5-HT3a receptor were analyzed using immunohistochemistry and western blotting. The expression levels of various factors related to central sensitization were measured by western blot, including c-Fos, GFAP, IBA-1, IL-1ß and TNF-α. The effects of 5-HT3a receptor antagonists on hyperalgesia were assessed through behavioral tests after intrathecal administration of ondansetron. Additionally, at 120 min postinjection, the SDH of rats was acquired, and the change of expression levels of protiens related to central sensitization were measured by western blot. RESULTS: BPA induced mechanical and cold hypersensitivity in rats. The 5-HT3a receptor was increased and mainly distributed on neurons and microglia in the SDH after BPA, and the level of central sensitization and expression of inflammatory factors, such as c-Fos, GFAP, IBA-1, IL-1ß and TNF-α, were also increased markedly. Ondansetron, which is a selective 5-HT3a receptor antagonist, reversed the behavioral changes caused by BPA. The antagonist also decreased the expression of central sensitization markers and inflammatory factors. CONCLUSION: The results suggested that the 5-HT3a receptor is involved in neuropathic pain by regulating central nervous system sensitization in a rat brachial plexus avulsion model. Targeting the 5-HT3a receptor may be a promising approach for treating neuropathic pain after brachial plexus avulsion.

How to prevent injury to the palmar cutaneous branch of median nerve and ulnar nerve in a palmar incision in carpal tunnel release, a cadaveric study.

OBJECTIVE: To identify palmar cutaneous branches of median nerve and ulnar nerve (PCBMN and PCBUN) and try to find a safe path at wrist and forearm in the decompression procedure of carpal tunnel syndrome. MATERIALS AND METHODS: Ten formalin-fixed and five fresh-frozen cadaveric forearms were included in the study. The cross point of longitude of middle finger and distal wrist crease was defined as 0 point. Distal wrist crease (DWC) and 0 point were chosen as references for measurements. Several points on the pathway of PCBMN and PCBUN were measured. RESULTS: The average distance between the origin of the PCBMN and PCBUN to the DWC was 4.95 ± 0.88 cm, 10.12 ± 1.50 cm, separately. The average distance between DWC and the point where PCBMN and PCBUN separated from their trunk was found to be 2.09 ± 0.31 cm, 2.90 ± 0.50 cm, separately. The distances between PCBMN, PCBUN and 0 point at DWC level was found to be 0.61 ± 0.12 cm, 0.47 ± 0.31 cm, separately. The diameters of two cutaneous branches were 0.10 ± 0.02 cm, 0.11 ± 0.04 cm, separately. CONCLUSION: The general longitudinal palmar incision could avoid injuries to recurrent branch of median nerve and distal branches of palmar cutaneous nerve can be avoided macroscopically. The area about 5 mm ulnar and 6 mm radial to 0 point at wrist level was a relatively safe area.

Outcome of contralateral C7 transfer to two recipient nerves in 22 patients with the total brachial plexus avulsion injury.

The treatment of total brachial plexus avulsion injury is difficult with unfavorable prognosis. This report presents our experience on the contralateral C7 (CC7) nerve root transfer to neurotize two recipient nerves in the patients with total BPAI. Twenty-two patients underwent CC7 transfer to two target nerves in the injured upper limb. The patients' ages ranged from 13 to 48 years. The entire CC7 was transferred to pedicled ulnar nerve in the first stage. The interval between trauma and surgery ranged from 1 to 13 months. The ulnar nerve was transferred to recipients (median nerve and biceps branch or median nerve and triceps branch) at 2-13 months after first operation. The motor recovery of wrist and finger flexor to M3 or greater was achieved in 68.2% of patients, the sensory recovery of median nerve area recovered to S3 or greater in 45.5% of patients. The functional recovery of elbow flexor to M3 or greater was achieved in 66.7% of patients with repair of biceps branch and 20% of patients with repair of the triceps branch (P < 0.05). There were no statistical differences in median nerve function recovery at comparisons of the age younger and older than 20-years-old and the intervals between trauma and surgery. In conclusion, the use of CC7 transfer for repair two recipient nerves might be an option for treatment of total BPAI. The functional recovery of the repaired biceps branch appeared to be better than that of the triceps branch.

Comparison of reading man flap and skin grafting for closure of resultant donor defects in homodigital reverse flow flaps.

BACKGROUND: The reading man procedure is a valuable treatment option for circular defects of different parts of the body. The aim of this study was to compare reading man procedure and skin grafting for coverage of resultant donor defects in homodigital reverse flow flaps. METHODS: From January 2018 to October 2020, 38 patients underwent fingertip reconstruction using homodigital reverse flow flaps. The donor sites were resurfaced with full-thickness skin grafts in 20 patients and with reading man flaps in 18 patients. Flap survival, postoperative complications, operative time for closure of donor site, return work time, range of motion of the injured fingers, static two-point discrimination, and aesthetic results were evaluated. RESULTS: All the outcomes, including flap survival, postoperative complications, operative time for closure of donor site, return work time, range of motion of the injured fingers, static two-point discrimination, and aesthetic results, were similar between the two groups. No patients complained of cold intolerance or hypersensitivity. CONCLUSION: The reading man flap is useful and reliable for covering resultant donor defects in homodigital reverse flow flaps. The functional and aesthetic outcomes in both groups are similar.

The temporal and spatial signature of microglial transcriptome in neuropathic pain.

Microglial activation following peripheral nerve injury is crucial for neuropathic pain (NP) development; however, studies on time-specific and spatial characteristics of microglial transcriptome are scarce. Firstly, we comparatively analysed microglial transcriptome of different brain regions and multiple timepoints after nerve injury by analysing the gene expression profile of GSE180627 and GSE117320. Then, we performed a mechanical pain hypersensitivity test on 12 rat neuropathic pain models using von Frey fibres at various timepoints after nerve injury. To further explore the key gene clusters closely related to the neuropathic pain phenotype, we conducted a weighted gene co-expression network analysis (WGCNA) on the GSE60670 gene expression profile. Lastly, we performed a single-cell sequencing analysis on GSE162807 for identifying microglia subpopulations. We found that the trend of microglia's transcriptome changes after nerve injury was that mRNA expression changes mainly occur early after injury, which is also consistent with phenotypic changes (NP progression). We also revealed that in addition to spatial specificity, microglia are also temporally specific in NP progression following nerve injury. The WGCNA findings revealed that the functional analysis of the key module genes emphasized the endoplasmic reticulum's (ER's) crucial role in NP. In our single-cell sequencing analysis, microglia were clustered into 18 cell subsets, of which we identified specific subsets of two timepoints (D3/D7) post-injury. Our study further revealed the temporal and spatial gene expression specificity of microglia in neuropathic pain. These results contribute to our comprehensive understanding of the pathogenic mechanism of microglia in neuropathic pain.

The effect of intraoperative nerve identification technique on distally-based dorsal fasciocutaneous flap for thumb and fingertip reconstruction.

INTRODUCTION: Thumb and fingertip resurfacing continues to be a challenge for hand surgeons, as the treatment varies widely. Being donor nerves in the flap for sensory restoration, the dorsal cutaneous nerves in hand have been widely described in the literature. However, their applications in providing anatomical information to sufficiently harvest the longitudinal axis of a robust flap are usually underestimated. This study reports reconstruction of thumb and fingertip defects with the distally based dorsal fasciocutaneous (DDF) flap and explores the effect of intraoperative nerve identification technique on clinical outcomes. HYPOTHESIS: The nerve identification technique can contribute considerably to the improvement of flap circulation, with less risk of poor venous return. MATERIALS AND METHODS: A retrospective study was conducted in 89 patients who had thumb or fingertip defects treated with the DDF flap from February 2014 to June 2020. Patients were divided into two groups based on whether intraoperative nerve identification technique was used. Flap survival was evaluated. The follow-up was conducted by using smartphone or by face-to-face visit. Time for complete wound healing, time to return to work, hand performance, the total active motion of the joints and static two-point discrimination of flaps were analyzed. RESULTS: The 46 flaps (group A) that underwent intraoperative nerve identification technique had an 8.7% venous congestion rate versus a 27.9% venous congestion rate in the 43 flaps (group B) without using nerve identification technique (p=0.018). The mean follow-up was 11.08 (range 6-26) months. Time for complete wound healing and time to return to work were significantly shorter in group A (p=0.026 and p=0.012). Michigan Hand Outcomes Questionnaire (MHQ) scores were similar between groups. In the face-to-face follow-up, there was no significant difference in the total active motion of the injured fingers and static two-point discrimination between the two groups (p=0.657 and p=0.182). DISCUSSION: The use of nerve identification technique could decrease the odds of postoperative venous congestion in DDF flap for thumb and fingertip reconstruction, and result in improved outcomes in terms of time for complete wound healing and time to return to work. LEVEL OF EVIDENCE: III; retrospective comparative study.