Preoperative Vascular Imaging in Lower Extremity Free Flap Reconstruction: Comparison Between Imaging Modalities.

BACKGROUND: Adequate vascular anatomy and perfusion status are essential for successful lower extremity free tissue transfer. Computed tomography angiography (CTA) is widely available, minimally invasive, and enables visualization of soft tissues and bones. Angiography permits temporal evaluation of flow, identifies potential needs for concurrent endovascular interventions, and enhances visibility in the setting of hardware. Despite widespread availability of these imaging modalities, no standardized algorithm for preoperative imaging prior to lower extremity free flap reconstruction exists. METHODS: Current Procedural Terminology (CPT) codes identified patients undergoing free flap reconstruction of the lower extremity over an 18-year period (2002-2020). Electronic medical records were reviewed for patient, treatment, and imaging characteristics, and pre- and post-imaging laboratory values. Outcomes included imaging findings and related complications and surgical outcomes. RESULTS: In total, 405 patients were identified, with 59% (n = 238) undergoing preoperative imaging with angiography, 10% (n = 42) with CTA, 7.2% (n = 29) with both imaging modalities, and 24% (n = 96) with neither performed. Forty percent (122 of 309) of patients who underwent preoperative imaging had less than 3-vessel runoff. Four patients developed contrast-induced nephropathy (CIN) after angiography only and one after having both CTA and angiography. Vessel runoff on CTA and angiography demonstrated moderate correlation. CONCLUSION: Most patients undergoing lower extremity free tissue transfer underwent preoperative imaging with angiography and/or CTA, 40% of which had less than 3-vessel runoff. Both angiography and CTA had low complication rates, with no statistically significant risk factors identified. Specifically, the incidence of CIN was not found to be significant using either modality. We discuss our institutional algorithm to aid in decision-making for preoperative imaging prior to lower extremity free flap reconstruction. Specifically, we recommend angiography for patients with peripheral vascular disease, internal hardware, or distal defects secondary to trauma.

Technical Variables in Lower Extremity Free Flap Reconstruction.

BACKGROUND: Lower extremity free flap failure rates are higher than in other areas of the body. While prior studies assessed the effect of intraoperative technical variables, these generally investigated individual variables and did not examine relationships between the many individual technical decisions made during free tissue reconstruction. Our purpose was to investigate the effect of variation in intraoperative microsurgical techniques on flap outcomes in a diverse cohort of patients requiring lower extremity free flap coverage. METHODS: Consecutive patients undergoing free flap reconstruction of the lower extremity at two level 1 trauma centers from January 2002 to January 2020 were identified using Current Procedural Terminology codes, followed by a review of medical records. Information regarding demographics and comorbidities, indications, intraoperative technical details, and complications was collected. Outcomes of interest included an unplanned return to the operating room, arterial thrombosis, venous thrombosis, partial flap failure, and total flap failure. Bivariate analysis was performed. RESULTS: In total, 410 patients underwent 420 free tissue transfers. The median follow-up time was 17 months (interquartile ranges: 8.0-37). Total flap failure occurred in 4.9% (n = 20), partial flap failure in 5.9% (n = 24), and unplanned reoperation in 9.0% (n = 37), with arterial thrombosis in 3.2% (n = 13) and venous thrombosis in 5.4% (n = 22). Overall complications were significantly associated with recipient artery choice, with arteries other than PT and AT/DP having a higher rate (p = 0.033), and with arterial revisions (p = 0.010). Total flap failure was also associated with revision of the arterial anastomosis (p = 0.035), and partial flap failure was associated with recipient artery choice (p = 0.032). CONCLUSION: Many interoperative options and techniques are available when performing microvascular lower extremity reconstruction that leads to equally high success rates. However, the use of arterial inflow outside of the posterior tibial and anterior tibial arteries leads to a higher overall complication rate and partial flap failure rate. Intraoperative revision of the arterial anastomosis portends poorly for ultimate flap survival.

Massive Thymic Hyperplasia Masquerading as Cancer: A Case Report and Review of the Literature.

A 34-year-old woman presenting with abdominal pain, chest pressure, weight loss, and tachycardia was found to have an 11.4-cm anterior mediastinal mass associated with intrathoracic lymphadenopathy on chest computed tomography (Fig. 1A). Core needle biopsy was concerning for a type B1 thymoma. During this patient's initial workup, she was found to have both clinical and laboratory evidence of Graves' thyroiditis, raising diagnostic suspicion for thymic hyperplasia rather than thymoma. The case discussed here highlights the unique challenges that arise in the evaluation and management of thymic masses and serves as a prudent reminder that both benign and malignant disorders may present with mass-like changes.

Secondary Surgery after Lower Extremity Free Flap Reconstruction.

BACKGROUND: Microsurgical free tissue transfer may be the only reconstructive option for lower extremity limb salvage. However, the functional and aesthetic results following free tissue transfer after initial salvage may be suboptimal, thus requiring secondary operations to facilitate definitive wound healing and/or refinement. METHODS: A multi-institutional retrospective cohort study was performed including patients who underwent lower extremity free tissue transfer from January of 2002 to December of 2020. The authors' primary outcome variable was the presence of secondary surgery after free tissue transfer for lower extremity reconstruction. Independent variables (eg, wound cause, flap, donor type, recipient, comorbidities) were collected. Secondary surgery was categorized as (1) procedures for definitive wound closure and (2) refinement procedures. Multivariable logistic regression was performed to determine which variables were independently associated with the outcome. RESULTS: A total of 420 free tissue transfers for lower extremity reconstruction were identified. Secondary surgery was performed in over half (57%) of the patients. Presence of diabetes (OR, 2.0; P = 0.01; 95% CI, 1.2 to 3.5) and use of a latissimus dorsi donor (OR, 2.4; P = 0.037; 95% CI, 1.1 to 5.4) were predictors of wound closure procedures. Fasciocutaneous (OR, 3.6; P < 0.001; 95% CI, 1.8 to 7.2) and myocutaneous (OR, 3.0; P = 0.005; 95% CI, 1.5 to 9.9) flaps were predictors of refinement procedures when compared with muscle-only flaps with skin grafts. CONCLUSIONS: The majority of lower extremity free tissue reconstructions required secondary procedures to provide definitive wound closure and/or refinement. Overall, this study provides predictors of secondary surgery that will help formulate patients' expectations of lower extremity limb salvage. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.