Background
Approximately 12% of operations for traumatic neuropathy are for patients with segmental nerve loss and less than 50% of these injuries obtain meaningful functional recovery. Polyethylene glycol (PEG) therapy has been shown to improve functional outcomes after nerve severance and we hypothesized this therapy could also benefit nerve autografting.
Methods
A segmental rat sciatic nerve injury model was used, whereby a 0.5 cm defect was repaired with an autograft using microsurgery. Experimental animals were treated with solutions containing methylene blue (MB) and PEG; control animals did not receive PEG. Compound Actions Potentials (CAPs) were recorded before nerve transection, after solution therapy, and at 72 hours postoperatively. The animals underwent behavioral testing at 24 and 72 hours postoperatively. After sacrifice, nerves were fixed, sectioned, and immunostained to allow for quantitative morphometric analysis.
Results
The introduction of hydrophilic polymers greatly improved morphological and functional recovery of rat sciatic axons at 1–3 days following nerve autografting. PEG therapy restored CAPs in all animals and CAPs were still present 72 hours postoperatively. No CAPS were detectable in control animals. Footfall asymmetry scores and sciatic functional index scores were significantly improved for PEG therapy group at all time points (p <0.05 and p<0.001; p <0.001 and p <0.01). Sensory and motor axon counts were increased distally in nerves treated with PEG compared to control (p = 0.0189 and p = 0.0032).
Conclusions
PEG therapy improves early physiologic function, behavioral outcomes, and distal axonal density after nerve autografting.
Patients undergoing microvascular reconstruction are often anemic from a combination of iatrogenic hemodilution and acute blood losses. No major clinical study describes the impact of preoperative anemia on free flap morbidity. The plastic surgery service at a high-volume academic center performed 156 free flaps among 147 patients from December 2005 to December 2010. One hundred thirty-two had a preoperative hemoglobin (Hb) or hematocrit (Hct), with mean values of 11.8±2.4 g/dL and 35.2%±7.0%, respectively. The overall failure rate was 9% (12/132), primarily from vascular thrombosis (6/12). Through logistic regression analysis, Hb and Hct were significant predictors of flap failure (P<0.005) and vascular thrombosis (P<0.05). Fisher exact test revealed a significant increase in failure risk at Hct level less than 30% (Hb<10 g/dL) (relative risk, 4.76, P=0.006), and probit analysis demonstrated an exposure-response relationship to decreased Hct level (P<0.005). These findings support that preoperative anemia could significantly impact free flap morbidity.
Early free flap coverage in lower extremity trauma is a practice largely supported by research that may be outdated and is frequently impractical due to logistics, resuscitation efforts, and associated injuries. Our objective was to re-evaluate this paradigm to determine whether reconstructive timing impacts outcome in modern clinical practice. We reviewed 60 free flaps for traumatic lower extremity coverage from December 2005 to December 2010 by the plastic surgery service at an academic medical center. All reconstructions were >72-hours from injury, spanning from 3 days to 2.2 years. The overall failure rate was 13.3% (8/60). Statistical analysis yielded no significant associations between reconstructive timing and flap failure or morbidity, although there was a trend toward fewer failures among latest reconstructions (>91 days) compared to within 30 days (P = 0.053). These findings support that delays may be safely utilized to allow patient and wound optimization without negatively impacting outcomes in free tissue transfer.
For the high-risk breast cancer patient, a combined mastectomy, free flap reconstruction, and gynecologic procedure represents an attractive and safe option.
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