Long-gap peripheral nerve repair through sustained release of a neurotrophic factor in nonhuman primates.

Severe injuries to peripheral nerves are challenging to repair. Standard-of-care treatment for nerve gaps >2 to 3 centimeters is autografting; however, autografting can result in neuroma formation, loss of sensory function at the donor site, and increased operative time. To address the need for a synthetic nerve conduit to treat large nerve gaps, we investigated a biodegradable poly(caprolactone) (PCL) conduit with embedded double-walled polymeric microspheres encapsulating glial cell line-derived neurotrophic factor (GDNF) capable of providing a sustained release of GDNF for >50 days in a 5-centimeter nerve defect in a rhesus macaque model. The GDNF-eluting conduit (PCL/GDNF) was compared to a median nerve autograft and a PCL conduit containing empty microspheres (PCL/Empty). Functional testing demonstrated similar functional recovery between the PCL/GDNF-treated group (75.64 ± 10.28%) and the autograft-treated group (77.49 ± 19.28%); both groups were statistically improved compared to PCL/Empty-treated group (44.95 ± 26.94%). Nerve conduction velocity 1 year after surgery was increased in the PCL/GDNF-treated macaques (31.41 ± 15.34 meters/second) compared to autograft (25.45 ± 3.96 meters/second) and PCL/Empty (12.60 ± 3.89 meters/second) treatment. Histological analyses included assessment of Schwann cell presence, myelination of axons, nerve fiber density, and g-ratio. PCL/GDNF group exhibited a statistically greater average area occupied by individual Schwann cells at the distal nerve (11.60 ± 33.01 µm2) compared to autograft (4.62 ± 3.99 µm2) and PCL/Empty (4.52 ± 5.16 µm2) treatment groups. This study demonstrates the efficacious bridging of a long peripheral nerve gap in a nonhuman primate model using an acellular, biodegradable nerve conduit.

Perioperative Narcotic Use and Carpal Tunnel Release: Trends, Risk Factors, and Complications.

Background: The goals of the study were to: (1) evaluate trends in preoperative and prolonged postoperative narcotic use in carpal tunnel release (CTR); (2) characterize risks for prolonged narcotic use; and (3) evaluate narcotic use as an independent risk factor for complications following CTR. Methods: A query of a large insurance database from 2007-2016 was conducted. Patients undergoing open or endoscopic CTR were included. Revision surgeries or patients undergoing median nerve repair at the forearm, upper extremity fasciotomies, or with distal radius fractures were excluded. Preoperative use was defined as narcotic use between 1 to 4 months prior to CTR. A narcotic prescription between 1 and 4 months after surgery was considered prolonged postoperative use. Demographics, comorbidities, and other risk factors for prolonged postoperative use were assessed using a regression analysis. Subgroup analysis was performed according to the number of preoperative narcotic prescriptions. Narcotic use as a risk factor for complications, including chronic regional pain syndrome (CRPS) and revision CTR, was assessed. Results: In total, 66 077 patients were included. A decrease in prescribing of perioperative narcotics was noted. Risk factors for prolonged narcotic use included preoperative narcotic use, drug and substance use, lumbago, and depression. Preoperative narcotics were associated with increased emergency room visits, readmissions, CRPS, and infection. Prolonged postoperative narcotic use was linked to CRPS and revision surgery. Conclusions: Preoperative narcotic use is strongly associated with prolonged postoperative use. Both preoperative and prolonged postoperative prescriptions narcotic use correlated with increased risk of complications. Preoperative narcotic use is associated with a higher risk of postoperative CRPS.

Particle size in fat graft retention: A review on the impact of harvesting technique in lipofilling surgical outcomes.

Fat grafting popularity continues to rise among plastic surgeons. As a soft tissue filler, adipose tissue had many desirable attributes: it is easy to obtain, autologous, and may reintegrate into recipient sites. However, fat grafting is clinically plagued by unpredictable resorption rates, thus there is much interest in optimizing the procedure of fat grafting for consistent graft volumes. Fat harvesting, a part of fat transfer surgery, involves the removal of adipose tissue from the donor site. Different harvest procedures, such as whole fat excision or liposuction cannulas, result in a range of fat particle volumes, which may play a role in the cellular stability of grafts. The ideal harvesting technique and fat particle diameter is not currently known. This study aims to review the literature on the impact of fat particle size and clinical fat grafting outcomes, to present overarching conclusions, and to provide future directions for study. Current evidence supports excisional methods and larger bore cannulas to minimize cellular damage, preserve the native architecture, and maximize the number of cells within fat particles.

Can we trust intraoperative culture results in nonunions?

OBJECTIVES: To identify the presence of bacterial biofilms in nonunions comparing molecular techniques (multiplex polymerase chain reaction and mass spectrometry, fluorescent in situ hybridization) with routine intraoperative cultures. METHODS: Thirty-four patients with nonunions were scheduled for surgery and enrolled in this ongoing prospective study. Intraoperative specimens were collected from removed implants, surrounding tissue membrane, and local soft tissue followed by standard culture analysis, Ibis's second generation molecular diagnostics (Ibis Biosystems), and bacterial 16S rRNA-based fluorescence in situ hybridization (FISH). Confocal microscopy was used to visualize the tissue specimens reacted with the FISH probes, which were chosen based on the Ibis analysis. RESULTS: Thirty-four patient encounters were analyzed. Eight were diagnosed as infected nonunions by positive intraoperative culture results. Ibis confirmed the presence of bacteria in all 8 samples. Ibis identified bacteria in a total of 30 of 34 encounters, and these data were confirmed by FISH. Twenty-two of 30 Ibis-positive samples were culture-negative. Four samples were negative by all methods of analysis. No samples were positive by culture, but negative by molecular techniques. CONCLUSIONS: Our preliminary data indicate that molecular diagnostics are more sensitive for identifying bacteria than cultures in cases of bony nonunion. This is likely because of the inability of cultures to detect biofilms and bacteria previously exposed to antibiotic therapy. LEVEL OF EVIDENCE: Diagnostic Level I. See Instructions for Authors for a complete description of levels of evidence.