Free flap reconstruction following head and neck trauma.

BACKGROUND: Free flap (FF) reconstruction of traumatic injuries to the head and neck is uncommon. METHODS: Multi-institutional retrospective case series of patients undergoing FF reconstruction for a traumatic injury (n = 103). RESULTS: Majority were gunshot wounds (GSW; 85%, n = 88) and motor vehicle accidents (11%, n = 11). Majority underwent osseous reconstruction (82%, n = 84). FF failures (9%, n = 9/103) occurred in GSW patients (100%, n = 9/9) and when multiple subsites were injured (89%, n = 8/9). Preoperative antibiotics correlated with lower rates of a neck washouts (4% vs. 19%) (p = 0.01) and 30-day readmissions (4% vs. 17%) (p = 0.02). CONCLUSIONS: All FF failures occurred in the setting of a GSW and the majority involved multiple subsites. Preoperative antibiotics correlated with lower rates of postoperative washout procedures and 30-day readmission.

The Palatal Island Flap for the Reconstruction of Oral and Oropharyngeal Defects.

The palatal island rotation flap is a rarely used reconstructive technique. The tissue is robust and the morbidity is low. It can be used as a primary reconstructive technique in patients with limited oral cavity/pharynx lesions. Healing is uneventful. In radiated pateints healing is prolonged and should be avoided. We describe 14 patients where the flap was used to reconstruct local defects. Patients with no history of radiation all healed quickly and well. Those with a history of radiatiuon had prolonged pain and delayed healing. Laryngoscope, 2023.

Outcomes of Cranioplasty Reconstructions: Review of Cranioplasty Implants and Free Flap Coverage Variables that Affect Implant Exposure.

BACKGROUND: Complex scalp wounds with cranial/dural involvement are challenging to reconstruct. Successful reconstruction can be achieved with cranial implants/hardware and free flap coverage. Wounds can breakdown and require revision procedures. We addressed reconstructive outcomes of different implants requiring free flaps. OBJECTIVE: To determine the factors associated with implant exposure. DESIGN: Multi-institutional retrospective review of 82 patients, 2000-2020, repaired with cranial implants and free flap coverage. RESULTS: Implant exposure occurred in 13/82 (16%) reconstructions. Flap atrophy or thinning leading to implant exposure occurred in 11/82 (13%) reconstructions, including partial flap atrophy OR 0.05 (95% CI 0.0-0.35) and total flap atrophy OR 0.34 (95% CI 0.02-19.66). Revision surgeries that occurred subsequent to flap reconstruction were also associated with implant exposure (OR 0.02 (95% CI 0.0-0.19)). Implant exposure was not associated with radiation therapy, patient health history, implant type, flap type, or postoperative complications. CONCLUSIONS: Implant exposure is associated with free flap atrophy, leading to inadequate implant coverage and the need for revision surgeries. Completing reconstruction with adequate soft tissue bulk and coverage and avoiding revision surgery may decrease the risk for implant exposure over time. LEVEL OF EVIDENCE: 4 Laryngoscope, 133:2954-2958, 2023.

Association of Head and Neck Anatomic Zones with Microvascular Reconstruction Outcomes.

Background: Head and neck free flap survival relies on adequate tissue perfusion from the external carotid artery (ECA), and vessel length is inversely proportional to blood flow rate. Objective: Investigate whether distance from the ECA (as a proxy for pedicle vessel length) predicts flap survival or complications. Methods: Retrospective review of free flaps performed at three academic centers from 9/2006 to 8/2021. Flaps were categorized by distance from the ECA: orbit and above (zone 1), maxilla to parotid (zone 2), and mandible and below (zone 3). Secondary analysis assessed flap outcomes stratified by average historical pedicle length. Results: A total of 2,369 flaps were identified in zones 1 (n = 109), 2 (n = 1878), and 3 (n = 382). Rates of flap failure (4.9%) and perioperative complications (36.3%) did not differ by zone or pedicle length. Zone 3 flaps, most commonly located in the larynx and hypopharynx, had significantly higher rates of fistula and infection. Conversely, 30-day readmission rates were significantly lower in patients with zone 2 flaps (p < 0.001). Rates of all other complications did not differ significantly between zones. Conclusions: Proximity to mucosal anatomic sites was a more powerful predictor of free flap viability than pedicle length or ECA proximity.

The Role of Fluorescent Angiography in Free Flap Reconstruction of the Head and Neck.

OBJECTIVES: Highlight the use of fluorescent angiography in free flap reconstruction of the head and neck. Qualify how fluorescent angiography can be selectively added to management paradigms for head and neck free flap reconstruction. METHODS: Retrospective chart review of 993 free flaps completed from the time the SPY Elite® system first became available at our institution between September 2013, until August 2020. Cases that used the SPY Elite® system were grouped into three broad categories: evaluation during initial flap harvest while still attached to the donor site, evaluation after anastomosis in the head and neck area, and evaluation post-operatively for questionable flap viability. RESULTS: The SPY Elite® system was used in 64 cases. Forty flaps were evaluated intraoperatively during initial harvest and before anastomosis to the head and neck area. Of these, 20 had signs of poor perfusion of the entire skin paddle, 12 had large myogenous or skin flaps with questionable perfusion of the distal aspect, and 8 were evaluated for other reasons. In this group the use of SPY Elite® changed the management of the patient in 20 cases (50%). Ten flaps were evaluated intraoperatively after anastomosis to the head and neck to ascertain adequate flow to the entire flap. In this group management was changed in two (20%). Fourteen flaps were evaluated 3-5 days post operatively due to suspected failure of a component. In five cases (36%), the use of SPY Elite® determined management with either trimming or discarding the flap. CONCLUSION: Assessment of flap perfusion via fluorescent angiography during initial flap harvest or when flap compromise is suspected post-operatively can guide decision making in free flap reconstruction of the head and neck and can be added to existing planning and management paradigms. LEVEL OF EVIDENCE: 4 Laryngoscope, 133:1388-1393, 2023.

Age and Comorbidities Impact Medical Complications and Mortality Following Free Flap Reconstruction.

OBJECTIVE: Determine if age correlated with surgical or medical complications following head and neck free flap reconstruction. STUDY DESIGN: Retrospective review of prospectively collected databases. METHODS: Patients undergoing head and neck free flap reconstruction at three tertiary care institutions were included (n = 1972). Cohorts were based on age (<65, 65-75, 75-85, and >85). Outcomes reviewed operative duration, length of stay, surgical complications (free flap failure, fistula, hematoma, dehiscence, and infection), and medical complications (thromboembolism, stroke, cardiac, and pulmonary). RESULTS: Anatomic site (P < .0001) and donor site varied by age (P < .0001). There was no difference in operative duration (P = .3) or length of hospitalization (P = .8) by age. The incidence of medical complications increased with increasing age. Pulmonary complication rates: <65 (3.9%), 65 to 75 (4.8%), 75 to 85 (7.1%), and >85 (11%) (P = .02). Cardiac complication rates: <65 (2.0%), 65 to 75 (7.3%), 75 to 85 (6.1%), and >85 (16.4%) (P < .0001). Mortality increased with age: <65 (0.4%), 65 to 75 (0.8%), 75 to 85 (1.1%), and >85 (4.1%) (P < .003). Medical complications correlated with mortality rates: pulmonary (3.5% vs. 0.6%; OR: 5.5; 95% CI: 1.5-20.0; P = .004); cardiac (3.3% vs. 0.6%; OR: 6.0; 95% CI: 1.6-21.8; P = .002); thromboembolism (4.6% vs. 0.7%; OR: 7.3; 95% CI: 1.6-33.6; P = .003); stroke (42% vs. 0.5%; OR: 149; 95% CI: 40-558; P < .0001); and sepsis (5% vs. 0.7%; OR 7.5; 95% CI: 1.0-60.5; P = .03). Age did not correlate with free flap success (P = .5), surgical complications (hematoma, P = .33; fistula, P = .23; infection, P = .07; and dehiscence, P = .37), or thirty-day readmission (P = .3). CONCLUSION: Following free flap reconstruction, patient age did not correlate with development of a surgical complication. Patient age did correlate with development of a medical complication. Postoperative medical complications were found to correlate with perioperative mortality. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:772-780, 2022.

Outcomes of Venous End-to-Side Microvascular Anastomoses of the Head and Neck.

OBJECTIVES/HYPOTHESIS: The literature on outcomes of end-to-side (ETS) anastomoses for microvascular reconstruction of the head and neck is limited. This series reviews ETS in free tissue transfer (FTT) across multiple institutions to better understand their usage and associated outcomes. STUDY DESIGN: Retrospective review of 2482 consecutive patients across three tertiary institutions. METHODS: Adult patients (> 18) who received a FTT from 2006 to 2019 were included. RESULTS: Two hundred and twenty-one FTT were identified as requiring at least one ETS anastomosis. These ETS cases had a failure rate of 11.2% in comparison to 3.8% in a cohort of end-to-end (ETE) cases (P < .001). ETS cases were significantly more likely to have a prior neck dissection (P < .001), suggesting the ETS method was utilized in select circumstances. A second ETS anastomosis improved survival of the FTT (P = .006), as did utilization of a coupler over suture (P = .002). Failure due to venous thrombosis was significantly more common with one ETS anastomosis instead of two ETS anastomoses (P = .042). CONCLUSIONS: ETS is effective but is often used as a secondary technique when ETE is not feasible; as such, in this series, ETS was associated with higher failure. A second anastomosis and the use of the coupler for completing the anastomoses were associated with lower rates of failure. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:1286-1290, 2021.

Inflammation up-regulates cochlear expression of TRPV1 to potentiate drug-induced hearing loss.

Aminoglycoside antibiotics are essential for treating life-threatening bacterial infections, despite the risk of lifelong hearing loss. Infections induce inflammation and up-regulate expression of candidate aminoglycoside-permeant cation channels, including transient receptor potential vanilloid-1 (TRPV1). Heterologous expression of TRPV1 facilitated cellular uptake of (fluorescently tagged) gentamicin that was enhanced by agonists, and diminished by antagonists, of TRPV1. Cochlear TRPV1 was immunolocalized near the apical membranes of sensory hair cells, adjacent supporting cells, and marginal cells in the stria vascularis. Exposure to immunostimulatory lipopolysaccharides, to simulate of bacterial infections, increased cochlear expression of TRPV1 and hair cell uptake of gentamicin. Lipopolysaccharide exposure exacerbated aminoglycoside-induced auditory threshold shifts and loss of cochlear hair cells in wild-type, but not in heterozygous Trpv1+/- or Trpv1 knockout, mice. Thus, TRPV1 facilitates cochlear uptake of aminoglycosides, and bacteriogenic stimulation upregulates TRPV1 expression to exacerbate cochleotoxicity. Furthermore, loss-of-function polymorphisms in Trpv1 can protect against immunogenic exacerbation of aminoglycoside-induced cochleotoxicity.

Potential Mechanisms Underlying Inflammation-Enhanced Aminoglycoside-Induced Cochleotoxicity.

Aminoglycoside antibiotics remain widely used for urgent clinical treatment of life-threatening infections, despite the well-recognized risk of permanent hearing loss, i.e., cochleotoxicity. Recent studies show that aminoglycoside-induced cochleotoxicity is exacerbated by bacteriogenic-induced inflammation. This implies that those with severe bacterial infections (that induce systemic inflammation), and are treated with bactericidal aminoglycosides are at greater risk of drug-induced hearing loss than previously recognized. Incorporating this novel comorbid factor into cochleotoxicity risk prediction models will better predict which individuals are more predisposed to drug-induced hearing loss. Here, we review the cellular and/or signaling mechanisms by which host-mediated inflammatory responses to infection could enhance the trafficking of systemically administered aminoglycosides into the cochlea to enhance the degree of cochleotoxicity over that in healthy preclinical models. Once verified, these mechanisms will be potential targets for novel pharmacotherapeutics that reduce the risk of drug-induced hearing loss (and acute kidney damage) without compromising the life-saving bactericidal efficacy of aminoglycosides.