Hongjiang Ruan

Aligned natural–synthetic polyblend nanofibers for peripheral nerve regeneration

Peripheral nerve regeneration remains a significant clinical challenge to researchers. Progress in the design of tissue engineering scaffolds provides an alternative approach for neural regeneration. In this study aligned silk fibroin (SF) blended poly(L-lactic acid-co-ε-caprolactone) (P(LLA-CL)) nanofibrous scaffolds were fabricated by electrospinning methods and then reeled into aligned nerve guidance conduits (NGC) to promote nerve regeneration. The aligned SF/P(LLA-CL) NGC was used as a bridge implanted across a 10mm defect in the sciatic nerve of rats and the outcome in terms of of regenerated nerve at 4 and 8 weeks was evaluated by a combination of electrophysiological assessment and histological and immunohistological analysis, as well as electron microscopy. The electrophysiological examination showed that functional recovery of the regenerated nerve in the SF/P(LLA-CL) NGC group was superior to that in the P(LLA-CL) NGC group. The morphological analysis also indicated that the regenerated nerve in the SF/P(LLA-CL) NGC was more mature. All the results demonstrated that the aligned SF/P(LLA-CL) NGC promoted peripheral nerve regeneration significantly better in comparison with the aligned P(LLA-CL) NGC, thus suggesting a potential application in nerve regeneration.

Peripheral nerve regeneration using composite poly(lactic acid-caprolactone)/nerve growth factor conduits prepared by coaxial electrospinning

Many neurotrophic factors have been shown to promote neurite outgrowth by improving the microenvironment that is required for nerve regeneration. However, the delivery of these bioactive agents to the nerve injury site, as well as effective and local release, remains a challenging problem. We have developed a novel composite nerve conduit comprised of poly(lactic acid-caprolactone) (P(LLA-CL)) and nerve growth factor (NGF). This was developed from core-shell structured biodegradable nanofibers, which were fabricated by coaxial electrospinning of P(LLA-CL) for the shell and bovine serum albumin (BSA) or BSA/NGF for the core. In rats, gaps of 10-mm long sciatic nerves were bridged using an autograft, an empty P(LLA-CL) conduit, a NGF injection P(LLA-CL) conduit, a P(LLA-CL)/NGF composite conduit, respectively. Regenerated nerve fibers were harvested and morphological and functional evaluation of nerve regeneration was performed at 12 weeks postsurgery. Although partial biodegradation and small cracks in the conduits were observed, the conduit outlines remained intact for 12 weeks after surgery. Based on functional and histological observations, the number and arrangement of regenerated nerve fibers, myelination, and nerve function reconstruction was similar in the P(LLA-CL)/NGF conduit group to that of the nerve autograft group (p > 0.05), but was significantly greater to the empty P(LLA-CL) and injection NGF P(LLA-CL) conduit groups (both p < 0.05). Therefore, the composite P(LLA-CL)/NGF conduit, which exhibited favorable mechanical properties and biocompatibility, could effectively promote sciatic nerve regeneration in rats.

Biomimetic sheath membrane via electrospinning for antiadhesion of repaired tendon.

The hierarchical architecture and complex biologic functions of native sheath make its biomimetic substitute a daunting challenge. In this study, a biomimetic bilayer sheath membrane consisting of hyaluronic acid-loaded poly(ε-caprolactone) (HA/PCL) fibrous membrane as the inner layer and PCL fibrous membrane as the outer layer was fabricated by a combination of sequential and microgel electrospinning technologies. This material was characterized by mechanical testing and analysis of morphology, surface wettability, and drug release. Results of an in vitro drug release study showed sustained release. The outer layer had fewer cells proliferating on its surface compared to tissue culture plates or the inner layer. In a chicken model, peritendinous adhesions were reduced and tendon gliding were improved by the application of this sheath membrane. Taken together, our results demonstrate that such a biomimetic bilayer sheath can release HA sustainably as well as promoting tendon gliding and preventing adhesion.

The Effect of Aligned Core–Shell Nanofibres Delivering NGF on the Promotion of Sciatic Nerve Regeneration

Recent bioengineering strategies for peripheral nerve regeneration have been focusing on the development of alternative treatments for nerve repair. In this study, we incorporated nerve growth factor (NGF) into aligned core–shell nanofibres by coaxial electrospinning, and reeled the scaffold into aligned fibrous nerve guidance conduits (NGCs) for nerve regeneration study. This aligned PLGA/NGF NGC combined physical guidance cues and biomolecular signals to closely mimic the native extracellular matrix (ECM). The effect of this aligned PLGA/NGF NGC on the promotion of nerve regeneration was evaluated in a 13-mm rat sciatic nerve defect using functional and morphological analysis. After 12 weeks implantation, the results of electrophysiological and muscle weight examination demonstrated that the functional recovery of the regenerated nerve in the PLGA/NGF NGC group was significantly better than that in the PLGA group, yet had no significant difference compared with the autograft group. The toluidine blue staining study showed that more nerve fibres were regenerated in the PLGA/NGF group, while the electron microscopy study indicated that the regenerated nerve in the PLGA/NGF group was more mature than that in the PLGA group. This study demonstrated that the aligned PLGA/NGF could greatly promote peripheral nerve regeneration and have a potential application in nerve regeneration.

Incidence, management, and prognosis of early ulnar nerve dysfunction in type C fractures of distal humerus.

BACKGROUND Displaced comminuted of the distal humerus in adults are among the most complex fractures to be managed effectively. The ulnar nerve is at high risk of impingement secondary to injury, operation, and postoperative rehabilitation in these fractures. In this study we focus on the incidence, management, and prognosis of early ulnar nerve dysfunction in the course of treating type C fractures of distal humerus. METHODS We examine a patient sample of 117 consecutive AO type C fractures of distal humerus, between June 1998 and October 2005. Twenty-nine patients exhibited preoperative ulnar nerve compression symptoms (incidence 24.8%) and were divided into two groups randomly, which received treatment of anterior subfascial transposition or in situ decompression of the ulnar nerve respectively, in conjunction with internal fixation with medial and lateral plates. RESULTS The subgroup of 88 patients without preoperative ulnar nerve symptoms remained asymptomatic postoperatively (0% incidence of late ulnar nerve dysfunction). According to Bishop rating system, excellent and good results of ulnar nerve function were achieved in 13 of 15 patients (86.7%) in the transposition group, 8 of 14 patients (57.1%) in the in situ decompression group. The results difference is statistically significant (p < 0.05). CONCLUSIONS We conclude that neurolysis and anterior subfascial transposition of vascularized ulnar nerve during open reduction and internal fixation of type C fractures of the distal humerus is beneficial in cases of early ulnat nerve dysfunction.

Double-column fixation for type C fractures of the distal humerus in the elderly

BACKGROUND Although several studies reported good results of open reduction and internal fixation of displaced fracture of the adult distal humerus, few studies have specifically addressed the results of such surgical fixation in osteoporotic bone in the elderly. METHODS This study focused on AO type C fractures in the elderly by using 2 plates for fixation of the lateral and medial columns to reconstruct a stable triangular frame of the distal humerus. The study comprised 35 patients, and 32 were available for final evaluation at a mean follow-up of 24.5 months (range, 14-60 months). RESULTS Mayo Elbow Function Score showed 25 patients (78%) achieved an excellent functional result, and 7 (22%) had a good result. No patients were considered to have a fair or poor result. At the final follow-up, the mean range of flexion to extension of the elbow was 22 degrees (range, 10 degrees -40 degrees) to 125 degrees (range, 100 degrees -140 degrees). All fractures united at average of 3.5 months (range, 2.5-5.3 months). CONCLUSION Open reduction and internal fixation using double-columned plating is a useful and effective technique in the management of displaced, comminuted, intra-articular fractures of the distal humerus in elderly patients. LEVEL OF EVIDENCE Level 4; Case series, treatment study.

Antibacterial and anti-adhesion effects of the silver nanoparticles-loaded poly(L-lactide) fibrous membrane.

The complications of tendon injury are frequently compromised by peritendinous adhesions and tendon sheath infection. Physical barriers for anti-adhesion may increase the incidence of postoperative infection. This study was designed to evaluate the potential of silver nanoparticles (AgNPs)-loaded poly(L-lactide) (PLLA) electrospun fibrous membranes to prevent adhesion formation and infection. Results of an in vitro drug release study showed that a burst release was followed by sustained release from electrospun fibrous membranes with a high initial silver content. Fewer fibroblasts adhered to and proliferated on the AgNP-loaded PLLA electrospun fibrous membranes compared with pure PLLA electrospun fibrous membrane. In the antibacterial test, the AgNP-loaded PLLA electrospun fibrous membranes can prevent the adhesion of Gram-positive Staphylococcus aureus and Staphylococcus epidermidis and Gram-negative Pseudomonas aeruginosa. Taken together, these results demonstrate that AgNP-loaded PLLA electrospun fibrous membranes have the convenient practical medical potential of reduction of infection and adhesion formation after tendon injury.

Combination of Arthrolysis by Lateral and Medial Approaches and Hinged External Fixation in the Treatment of Stiff Elbow

BACKGROUND Various methods are available to treat the stiff elbow. However, there is no consensus on which one is most useful. This study involves the effects of combination of arthrolysis by lateral and medial approaches and hinged external fixation in the treatment of stiff elbow. PATIENTS We treated 12 patients with stiff elbows using a combination of arthrolysis by lateral and medial approaches and hinged external fixation. The arthrolysis was applied to the elbow for complete soft-tissue release, and the hinged external fixation mainly for rehabilitation and stability of the elbow after arthrolysis. With the help of the hinged external fixation, nonsurgical treatment including exercises was effectively performed to maintain the stability and the results of arthrolysis. Before surgery, the mean extension was -35 degrees and the mean flexion 70 degrees. One patient had a loss of 70 degrees in pronation. RESULTS Satisfactory follow-up was given to 11 patients with the mean length of 15 month. The mean postoperative extension was -8 degrees whereas flexion 122 degrees. Two of 11 patients had a transient ulnar paresthesia and returned to normal after 8-month follow-up. The loss of pronation in one patient reduced to 30 degrees afterward. There were no complicating infections. All patients reported satisfactory effect. CONCLUSION The combination of arthrolysis by lateral and medial approaches and hinged external fixation in the treatment of stiff elbow is safe and effective.

The efficacy of celecoxib in preventing heterotopic ossification recurrence after open arthrolysis for post-traumatic elbow stiffness in adults

BACKGROUND Heterotopic ossification (HO) recurrence after joint surgery is always a disturbing problem for patients and surgeons. Our study was performed to assess the efficacy and safety of celecoxib in preventing the recurrence of HO after open arthrolysis for post-traumatic elbow stiffness. METHODS We retrospectively studied 152 patients with stiff elbows caused by post-traumatic HO. After surgery, 77 patients received celecoxib (200 mg once daily) for 28 days, whereas 75 did not. Radiographic evaluation was performed at 3, 6, and 9 months postoperatively. Univariate and multivariate analyses were performed to determine which factors affected HO recurrence. RESULTS HO was both more common and more severe in the no-celecoxib group than in the celecoxib group at 3, 6, and 9 months after surgery. A significant difference was observed between the 2 groups in terms of postoperative extension (P = .030), flexion (P = .008), and pronation (P = .005); however, no significant difference in postoperative supination was noted (P = .622). Logistic regression analysis showed that taking celecoxib was the protective factor for HO recurrence, whereas overweight (body mass index > 25) and male gender were the risk factors. CONCLUSIONS A short course of celecoxib aids in the prevention of HO recurrence after open arthrolysis for elbow stiffness in adults and could be an effective and safe option.

Stability of severely stiff elbows after complete open release: treatment by ligament repair with suture anchors and hinged external fixator.

BACKGROUND Instability is a crucial issue in severe post-traumatic elbow stiffness during complete-release surgery. This study aimed to evaluate the efficacy of ligament repair using a suture anchor in the operative treatment of severely stiff elbows for which a hinged external fixator was indicated. METHODS We retrospectively reviewed 46 cases of severely stiff elbows (flexion arc <60°) undergoing open release. During the operation, all 46 elbows were noted to have instability. Suture anchors were applied to restore the ligament if it was impossible to repair the ligament directly, and a hinged external fixator was simultaneously applied to protect the vulnerable ligament and facilitate rehabilitation. No allograft or autograft was used in any of our cases. The stability, arc of motion, Mayo Elbow Performance Score, ulnar nerve symptoms, and radiographs were evaluated. RESULTS At a mean follow-up of 24.3 months, the postoperative Mayo Elbow Performance Score was 91 points, as compared with 63 points preoperatively. The mean flexion arc improved from 25° to 126°. Three patients presented with moderate elbow instability when the hinged external fixator was removed; however, all of them regained stability by the last follow-up. Furthermore, 7 cases of new-onset nerve palsy were noted; however, all of them resolved with conservative management. None of the patients required secondary surgery for any reason. CONCLUSIONS Repair of an avulsed collateral ligament with suture anchors and hinged external fixation was effective in restoring functional mobility in patients with severe post-traumatic elbow stiffness after complete release. This could be an option for treating ankylosed, severely or very severely stiff elbows.