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Naturally fractured formations usually have strong heterogeneities. Drilling and production operations in such formations can involve unwanted formation failure risks such as wellbore collapse and wellbore fracturing. This study presents a coupled thermal-hydraulic-mechanical numerical model for near-well stress evolutions during drilling in naturally fractured formations. The evolution of pressure, temperature, and geo-mechanical responses on the wellbore wall and in the near-well region is simulated. The effects of wellbore pressure, internal friction angle, and natural fracture length on formation rock risks are discussed. A failure index is used to quantify the formation rock failure risks. The existence of natural fractures magnifies the heterogeneous system response induced by drilling. Increasing the wellbore pressure from a relatively low value can improve the support for the wellbore wall, which reduces the failure risks caused by shearing. In mechanically weak formations, the effect of natural fractures on formation rock failure becomes more significant. When the natural fracture length is large, the near-well region tends to have greater failure risks as the formations become more mechanically weak. This study provides a quantitative understanding of the effects of drilling and formation parameters on failure risks.

OBJECTIVES: To analyze charges, complications, survival, and functional outcomes for definitive surgery of mandibular osteoradionecrosis (ORN). MATERIALS AND METHODS: Retrospective analysis of 76 patients who underwent segmental mandibulectomy with reconstruction from 2000 to 2009. RESULTS: Complications occurred in 49 (65%) patients and were associated with preoperative drainage (odds ratio [OR] 4.40, 95% confidence interval [CI] 1.01–19.27). The adjusted median charge was $343 000, and higher charges were associated with double flap reconstruction (OR 8.15, 95% CI 2.19–30.29) and smoking (OR 5.91, 95% CI 1.69–20.72). Improved swallow was associated with age

Computer-assisted surgery has become the mainstream in mandibular reconstruction, but the lack of a standard measuring approach for spatial deviations of mandible hinders postoperative verification and the comparison of different subjects. This study aims to set up a comprehensive approach for measuring spatial deviations of computer-assisted mandibular reconstruction.A systematic review was conducted to extract all measurements for computer-assisted mandibular reconstruction. Thereafter, eligible measurements were included in the authors' comprehensive approach, which categorized the measurements according to different anatomical structures and landmarks.A total of 80 studies were included in the authors' systematic review, and 31 measurements were extracted. The authors established a comprehensive panel of anatomical landmarks to facilitate measurement, including parts, points, lines, planes, and angles. These measurements encompassed spatial deviations of the overall mandible, condyle, gonial angle, bone grafts, midline, surgical plate, osteotomy, and miscellaneous indicators. A calculation spreadsheet was developed to collect landmarks and compute deviations automatically with built-in formulas. Finally, a simplified panel of measurements was recommended for spatial deviations of mandibular reconstruction.A comprehensive approach for measuring spatial deviations of computer-assisted mandibular reconstruction was established. Future studies will confirm this approach as an effective and scientific system for postoperative verification of computer-assisted mandibular reconstruction.

BACKGROUND Orbital exenteration (OE) is an ablative procedure used in the management of malignancies of the orbit of either primary or secondary origin. Publications evaluating this procedure have suffered from small patient numbers, heterogeneity of pathologies, and poor patient follow-up. The purpose of this study was to assess patient outcomes in a large cohort of patients undergoing OE at a tertiary cancer center. METHODS A retrospective review was conducted of 180 consecutive patients who underwent OE at the authors' institution. Overall survival (OS) was the primary end point measured in the study. Time to locoregional recurrence (progression-free survival [PFS]) and disease-free survival were secondary end points. RESULTS Between the years 1993 and 2011, 180 consecutive patients received OE for craniofacial malignancy at the authors' institution. The median follow-up for the cohort was 9.7 years (116 months). The median OS was 73 months, and the median PFS was 96 months. The presence of perineural invasion was associated with shorter OS (P = .01) and PFS (P < .01). Magnetic resonance imaging was predictive of perineural invasion (P < .01). Positive margins were associated with shorter PFS than negative margins (P < .01) but with no change in OS (P = .15). The overall complication rate was 15%. The major complication rate (Clavien-Dindo 3b or greater) was 2.8% (n = 5), and there was 1 death observed (0.6%). CONCLUSIONS Used judiciously in the setting of a multidisciplinary management plan, OE for tumor control is a safe therapy. LAY SUMMARY Between the years 1993 and 2011, 180 consecutive patients received orbital exenteration for craniofacial malignancy at the MD Anderson Cancer Center. The median follow-up for the cohort was 9.7 years. The presence of perineural invasion was associated with shorter overall survival (P = .01) and progression-free survival (P < .01). Magnetic resonance imaging was predictive of perineural invasion (P < .01). Positive margins were associated with shorter progression-free survival than negative margins (P < .01). The overall complication rate was 15%. The major complication rate (Clavien-Dindo 3b or greater) was 2.8% (n = 5).

BACKGROUND The posterior trunk is a technically demanding location for microvascular free tissue transfer. In this study, the authors report their own institutional experience with soft-tissue free flap reconstruction of the posterior trunk and provide a systematic review of the literature regarding this uncommon clinical scenario. METHODS A systematic review was performed using the PubMed database in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A single-institution retrospective review was also performed including all patients who received a soft-tissue free flap for a posterior trunk defect between 1990 and 2019. RESULTS The database search yielded 15 articles, representing 61 patients; the most commonly used flap was the latissimus dorsi (45.9 percent) and the most commonly reported defect location was the lumbosacrum (42.3 percent). Retrospective review of the authors' database identified 26 patients, with the latissimus dorsi being the most common flap and the sacrum the most common defect site. The authors' institutional case series showed a 30.7 percent major complication rate and 7.7 percent total flap loss rate; 38.4 percent of flaps required vein grafting. CONCLUSIONS In this study, the authors provided a systematic literature review and described their own long-term institutional experience with these rare and difficult reconstructions. Although the overall complication rate is high, these reconstructions are frequently necessary, and an algorithmic approach can improve outcomes. CLINICAL QUESTION/LEVEL OF EVIDENCE Therapeutic, IV.

Enhanced recovery after surgery (ERAS) pathways are well established in certain surgical specialties because findings have shown significant improvements in outcomes. Convincing literature in head and neck cancer (HNC) surgery is lacking. This study aimed to assess the effect of an ERAS pathway on National Surgical Quality Improvement Program (NSQIP)-based occurrences and pain-related outcomes in HNC surgery. The study matched 200 patients undergoing head and neck oncologic surgery on an ERAS pathway between 1 March 2016 and 31 March 2019 with control subjects (1:1 ratio) during the same period. Demographic and perioperative data collected from the NSQIP database were extracted. Pain scores and medication usage were electronically extracted from our electronic medical record system and compared. Risk factors for high opioid usage also were assessed. Both groups were statistically similar in baseline characteristics. The ERAS group had fewer planned intensive care unit (ICU) admissions (4% vs. 14%; p

Background Postoperative complications are an independent predictor of poor survival across several tumors. However, there is limited literature on the association between postoperative morbidity and long-term survival following total laryngectomy (TL) for cancer. Methods We conducted a retrospective review of all TL patients at a single institution from 2008 to 2013. Demographic and clinical data were collected and analyzed, including postsurgical outcomes, which were classified using the Clavien-Dindo system. Multivariable Cox regression analyses were performed to identify factors associated with overall survival (OS) and disease-free survival (DFS). Results A total of 362 patients were identified. The mean age was 64 years, and the majority of patients were male (81%). The median follow-up interval was 21 months. Fifty-seven percent of patients had received preoperative radiation, and 40% had received preoperative chemotherapy. Fifty-seven percent of patients underwent salvage TL, and 60% underwent advanced reconstruction (45% free flap and 15% pedicled flap). A total of 136 patients (37.6%) developed postoperative complications, 92 (25.4%) of which were major. Multivariable modeling demonstrated that postoperative complications independently predicted shorter OS (hazard ratio [HR], 1.50; 95% CI, 1.16-1.96; P = .002) and DFS (HR, 1.36; 95% CI, 1.05-1.76; P = .021). Other independent negative predictors of OS and DFS included positive lymph node status, preoperative chemotherapy, comorbidity grade, and delayed adjuvant therapy. Severity of complication and reason for TL (salvage vs primary) were not shown to be predictive of OS or DFS. Conclusion Postoperative complications are associated with worse long-term OS and DFS relative to uncomplicated cases. Patient optimization and timely management of postoperative complications may play a critical role in long-term survival.

Despite increasing recognition, obesity continues to represent a major health issue for millions of people in the USA and worldwide. There is a paucity in the literature regarding the effect of body mass index (BMI) on microsurgical head and neck reconstruction. The present study hypothesized that high BMI is predictive of postoperative recipient- and donor-site complications with longer operative times.Retrospective review of patients who underwent free flap surgery for head and neck reconstruction was performed between January 2005 and December 2018. Patients were categorized into four groups based on BMI:20 kg/mOverall, 4000 free flap surgeries were included in the present study, performed on 3753 patients, of whom 9.9% had a BMI20 kg/mObesity and high BMI increase operative times; however, with meticulous surgical technique and diligent postoperative care, microvascular head and neck reconstructions can be performed safely and reliably in the majority of patients regardless of BMI with similar overall, recipient-site, and donor-site complications.

We sought to determine overall survival (OS), prognostic factors, cost, and functional outcomes after surgery for locally recurrent oral cavity squamous cell carcinoma (OCSCC).We retrospectively reviewed 399 cases of locally recurrent OCSCC from 1997 to 2011, of which 259 patients were treated with salvage surgery. Survival and prognostic factors were evaluated using univariable and multivariable Cox regression, the Kaplan-Meier method, and the log-rank test.The 5-year OS for patients undergoing surgical salvage, nonsurgical therapy, or supportive care was 44.2%, 1.5%, and 0%, respectively. For patients who underwent surgical salvage, 133 (51%) patients experienced a second recurrence at a median of 17 months. Factors associated with OS included disease-free interval ≤ 6 months (P =.0001), recurrent stage III-IV disease (P lt;.0001), and prior radiation (P =.0001). Patients with both advanced stage and prior radiation had a 23% 5-year OS, compared with 70% for those with neither risk (P lt;.001). Functionally, 85% of patients had gt; 80% speech intelligibility and 81% were able to eat by mouth following salvage surgery. Of the patients who required tracheostomy, 78% were decannulated. The adjusted median hospital and professional charges for patients were $129,696 (range $9,238-$956,818).Patients with recurrent OCSCC who underwent salvage surgery have favorable functional outcomes with half of alive at 5 years but poorer OS for advanced disease, disease-free interval ≤ 6 months, and prior radiation. Additionally, treatment is associated with high cost, and about half of patients ultimately develop another recurrence.

Background When gastric pull-up is unsuccessful or unsuitable for total esophageal reconstruction, a supercharged pedicled jejunum can be used to reestablish gastrointestinal continuity. The authors reviewed their technique and outcomes of the supercharged pedicled jejunum for total esophageal reconstruction. Methods A retrospective review of a prospectively maintained database was performed of 100 patients who underwent supercharged pedicled jejunum for total esophageal reconstruction between 2000 and 2017 at the Texas Medical Center. Patient characteristics, technical details, and outcomes were analyzed. Results Mean patient age was 59.5 ± 11.4 years. Forty-two patients (42 percent) had surgical complications (18 percent at the recipient site, 13 percent at the donor site, and 11 percent at both). Medical complications occurred in 28 patients (28 percent). A major surgical complication occurred in 20 patients (20 percent). The average length of stay was 15 days (range, 6 to 152 days). At last follow-up, 20 patients (20 percent) had metastatic disease and six (6 percent) had local recurrence. Fifty-four patients (54 percent) died during the follow-up period. Of 79 patients with follow-up longer than 6 months, 68 (86 percent) tolerated a solid or soft oral diet, with a 16 percent tube feed-dependence rate. Overall survival at 1, 3, and 5 years was 78.8, 53.7, and 33.1 percent, respectively. The median survival time was 38.7 months. Conclusions The authors present their experience with 100 supercharged pedicled jejunums for total esophageal reconstruction. Functional outcomes are comparable to, or better than, other salvage modalities. With careful multidisciplinary planning and meticulous, well-orchestrated surgical technique, swallowing function can be restored to provide quality of life in patients with few remaining surgical options.

BACKGROUND Although the profunda artery perforator flap has gained popularity in breast reconstruction, it has not been well described for reconstruction of head and neck defects. The authors report their experience with free profunda artery perforator flaps in postoncologic head and neck reconstruction. METHODS A retrospective review of all free profunda artery perforator flaps used for head and neck reconstruction from 2016 to 2019 was performed. RESULTS Overall, 61 profunda artery perforator flap reconstructions were performed: 45 single independent flaps, 12 in conjunction with a second free flap, and four in combination with two other free flaps. The profunda artery perforator flaps were most commonly used for reconstruction of the tongue (n = 19), cheek (n = 11), parotid (n = 10), and maxilla (n = 6). The profunda artery perforator flaps averaged 7.1 × 12.1 × 1.9 cm, with a mean pedicle length of 11.5 cm. The A, B, and C perforators were located at mean distances of 7.4 cm (range, 4 to 11.5 cm), 11.7 cm (range, 8 to 18 cm), and 16.1 cm (range, 14 to 20.5 cm) from the pubic tubercle along the axis of the adductor longus muscle and 7.9 cm (range, 7 to 11cm), 7.6 cm (range, 7 to 15.5 cm), and 7.2 cm (range, 6 to 16 cm) posterior and perpendicular to the axis. There were three partial flap losses. Eight patients (13 percent) had recipient-site complications necessitating operative intervention: four for vascular compromise of the profunda artery perforator flap, two for hematoma evacuation, and two for infection. Donor-site complications were noted in seven patients (11 percent), two of whom required operative intervention. CONCLUSIONS The profunda artery perforator flap is a versatile and reliable flap with consistent anatomy and a low complication rate. The profunda artery perforator flap seems to be a reasonable alternative for reconstruction of head and neck defects. CLINICAL QUESTION/LEVEL OF EVIDENCE Therapeutic, IV.

BACKGROUND We aim to define a set of terms for common free flap complications with evidence-based descriptions. METHODS Clinical consensus surveys were conducted among a panel of head and neck/reconstructive surgeons (N = 11). A content validity index for relevancy and clarity for each item was computed and adjusted for chance agreement (modified kappa, K). Items with K

Background Deliberate fluid administration has been used to maintain a hyperdynamic systemic circulation in free tissue transfer operations. The effects of intraoperative volume loading on postoperative complications have been controversial. The authors hypothesized that increasing intraoperative fluid administration was associated with increased postoperative surgical complications. Methods Free flap operations for head and neck reconstruction between 2004 and 2014 were reviewed. A generalized estimating equation model was used to estimate the effect of intraoperative fluid administration on surgical outcomes. The optimized thresholds of anesthetic time were tested by the Youden index for flap compromise and major complications. Results A total of 2983 consecutive cases were included in the study. The incidences of flap compromise and total loss were 1.5 and 3.3 percent, respectively. Intraoperative fluid administration was not associated with surgical complications (p = 0.195). However, a 1-hour increase in anesthesia time was associated with a 19 percent increased risk of flap compromise (adjusted OR, 1.19; 95 percent CI, 1.10 to 1.29; p Conclusion Prolonged anesthetic time, but not fluid administration, was associated with adverse surgical outcomes. Clinical question/level of evidence Therapeutic, III.

Background Discovering alternatives to workhorse flaps that have more consistent anatomy and lower donor-site morbidity has become a focus of reconstructive surgery research. This study provides a simplified approach to profunda artery perforator flap design and harvest based on reliable anatomical landmarks. Methods A retrospective review was conducted of 70 patients who underwent 83 profunda artery perforator flap reconstructions for postoncologic defects from 2016 to 2018. The authors recorded and analyzed the profunda artery perforator flap sizes and clinical applications, the numbers and locations of the perforators, and the patient outcomes. Results Most of the profunda artery perforator flaps were for head and neck [46 patients (65.7 percent)] and breast [21 patients (30 percent)] reconstructions. Flaps were most commonly based on perforator A (33.7 percent) and perforator B (33.7 percent), followed by perforators B and C combined (18.1 percent). Perforators were located a mean of 7.5 cm (perforator A), 12.7 cm (B), and 17.6 cm (C) distal to the pubic tubercle parallel to the axis between the pubic tubercle and the medial femoral condyle and 7.9 cm (A), 7.3 cm (B), and 6.1 cm (C) posterior from the axis. There was no flap loss. One patient underwent successful salvage surgery after arterial flap thrombosis. Eight patients (9.6 percent) developed superficial wound dehiscence that was managed conservatively. Conclusions Perforator mapping demonstrated consistent anatomical locations of sizeable profunda artery perforators in the inner thigh. Along with its consistent and robust vascular anatomy and minimal donor-site morbidity, the profunda artery perforator flap's volume and pliability make it a reliable option for soft-tissue reconstruction. Clinical question/level of evidence Therapeutic, IV.

The lateral forearm flap-a thin, fasciocutaneous flap harvested over the lateral epicondyle based on the terminal anterior branch of the posterior radial collateral artery-is an attractive alternative to the radial forearm flap. The authors hypothesized that it is safe and effective for head and neck reconstruction. They conducted a retrospective review of all lateral forearm flap reconstructions performed between 2016 and 2018. Patient demographics, defect characteristics, adjuvant therapies, and postoperative complications were recorded. Swallowing and diet were assessed in patients undergoing intraoral reconstruction. The Disabilities of the Arm, Shoulder and Hand questionnaire was completed prospectively preoperatively and postoperatively. Flap and pedicle dimensions were recorded. Twenty-five lateral forearm flap reconstructions were performed; 23 were for intraoral defects. There were no partial or complete flap losses, one venous thrombosis, and one hematoma requiring reoperation. Preoperative and postoperative Disabilities of the Arm, Shoulder and Hand questionnaire scores were equivalent (p = 0.78). In the intraoral cohort, 22 patients (96 percent) resumed an oral diet following reconstruction. The average pedicle length was 11.8 cm (range, 9 to 16 cm); skin paddle length and width were 6.6 cm (range, 4 to 12 cm) and 4.7 cm (range, 4 to 12 cm), respectively; arterial diameter was 1.5 mm (range, 1.4 to 2.5 mm); and venous diameter was 2.8 mm (range, 2.4 to 3.6 mm). All donor sites were closed primarily; one superficial dehiscence was reported. In summary, the authors found that the free lateral forearm flap provided an excellent alternative to the radial forearm flap in head and neck reconstruction. It is a thin, pliable fasciocutaneous flap with excellent pedicle length, and the donor site can be closed primarily with minimal morbidity. CLINICAL QUESTION/LEVEL OF EVIDENCE:: Therapeutic, IV.

Objectives Computer assisted head and neck reconstruction has gained popularity over the past few years. In computer assisted surgery (CAS), surgical margins are predetermined in virtual surgery and resection guides are designed to be fitted intra-operatively. However, concerns have been raised regarding the oncological safety of predetermined surgical margins. Therefore, the aim of this study was to compare surgical margins, recurrence and survival outcomes in patients underwent CAS and non-CAS in head and neck reconstruction. Methods We retrospectively reviewed the patients underwent oral and maxillofacial malignancies surgical excision and free flap reconstruction from October 2014 to December 2019 by the same chief surgeon. Patients were divided into two groups depending on whether CAS and predetermined surgical margins were adopted. The primary outcome was surgical resection margin and the secondary outcomes included recurrence and survival. Results A total of 66 subjects were recruited with 37 in the CAS group and 29 in the non-CAS group. The follow-up rate was 100%. The average follow-up time was 24.5 months. No significant difference in resection margin was identified between the groups (p = 0.387). Tumor staging, margin status, perineural invasion, lymphovascular invasion and extranodal extension were identified as significant factors influencing survival. Both before and after adjustment for these prognostic factors identified, CAS and non-CAS group showed no significant difference in survival outcome. Conclusion Predetermined surgical margins do not compromise oncological safety in terms of resection margin, disease recurrence and patient survival.

Background Reconstruction of hemiglossectomy defects requires careful flap design to avoid adverse functional and aesthetic outcomes. Methods Hemitongue specimens were obtained from minipigs to study the three-dimensional anatomy and to define anatomic landmarks for precise measurements of flap requirement. The concept developed in animal models was then applied to hemiglossectomy reconstruction in clinical practice. Sixty-one patients were randomly enrolled into the following two groups: a "five-point eight-line segment" (FIPELS) flap design group (28 patients) and a conventional group (33 patients). Functional and aesthetic outcomes were compared between the two groups. Results All flaps designed with the FIPELS technique matched the hemiglossectomy defects without the need for flap trimming, thus reducing the operating time (P = .03). Swallowing functions, speech intelligibility, and aesthetic outcomes were superior in the FIPELS group than that in the conventional group (P Conclusions The FIPELS flap design for hemiglossectomy reconstruction yields improved functional and aesthetic outcomes compared to a conventional flap design.

To examine the effects of vasopressors on free flap outcomes.Most micro-surgeons avoid the use of vasopressors during free flap surgery due to concerns of vasoconstriction, which could potentially lead to vascular thrombosis and flap failure. Previous studies lack the statistical power to draw meaningful conclusions.All free flaps between 2004 and 2014 from a single institution were reviewed retrospectively. Vasopressors were given intraoperatively as an intravenous bolus when blood pressure dropped20% from baseline. The timing of intraoperative vasopressor administration was divided into 3 phases: from anesthesia induction to 30 minutes before the start of flap ischemia (P1); end of P1 to 30 minutes after revascularization (P2); end of P2 to end of surgery (P3). Agents included phenylephrine, ephedrine and calcium chloride.A total of 5671 free flap cases in 4888 patients undergoing head and neck, breast, trunk, or extremity reconstruction were identified. Vasopressors were used intraoperatively in 85% of cases. The overall incidence of pedicle compromise was 3.6%, with a flap loss rate of 1.7%. A propensity score matching analysis showed that intraoperative use of any agents at any time of surgery was not associated with increased overall pedicle compromise [51/1584 (3.2%) vs 37/792 (4.7%); P = 0.074] or flap failure rates [26/1584 (1.6%) vs 19/792 (2.4%); P = 0.209]. Rather, there was less risk of venous congestion [33/1584 (2.1%) vs 31/792 (3.9%); P = 0.010].Intraoperative use of phenylephrine, ephedrine, or calcium chloride as an intravenous bolus does not increase flap compromise and failure rates in cancer patients.

Background For organ transplant recipients, cancer secondary to immunosuppressive therapy threatens long-term survival. The associated multiple comorbidities make major free flap reconstruction following cancer surgery a complicated event. This study evaluates the outcomes of free flap reconstruction in this population. Methods A retrospective chart review of all head and neck free flap cases in patients with a history of organ transplantation receiving systemic immunosuppressive therapy between 2005 and 2017 at a single-institution was conducted. Results Of 57 organ transplant patients, 25 patients (28 flaps) were included. Flaps used included the anterolateral thigh (n = 17), radial forearm (n = 4), latissimus dorsi (n = 3), fibula (n = 2), lateral arm (n = 1), and thoracodorsal artery perforator (n = 1) flaps. The most common organ transplant was kidney, then lung, liver, and heart. Mean inpatient stay was 8.2 days (range, 4-28). Complications occurred in 15 patients, with no total or partial flap losses. Conclusion Major head and neck free flap reconstructive surgery can be performed safely in organ transplant patients receiving immunosuppressive therapy. Meticulous multidisciplinary care is required to achieve consistently successful outcomes.

Background Extensive flap salvage attempts are routinely performed in patients with late-onset flap vascular crisis despite low flap survival rates. A knowledge gap exists in management of compromised free flaps in patients who present with perfusion-related complications after hospital discharge. Methods A retrospective review of 7443 free flaps used in 7128 cancer patients at a single institution from January of 2001 to March of 2015 was performed. Results Of 7443 free flap reconstructions, 856 patients (12 percent) were taken back to the operating room. Also, 261 patients (4 percent) suffered from microvascular compromise, of whom 110 (1 percent) experienced total flap loss. The authors identified 17 patients (10 breast cancer patients and seven head and neck cancer patients) who had vascular flap compromise and underwent reoperation after hospital discharge (median, 10 days; range, 4 to 107 days) after free flap reconstruction. Of these 17 patients, nine breast cancer patients and two head and neck cancer patients underwent flap salvage attempts. Salvage procedures included thrombectomy, thrombolytic and heparin injections, and reanastomoses (11 patients); vein grafting (four patients); vein supercharging with cephalic turndown (two patients); and change of recipient vessels (two patients). Sixteen of the 17 patients (94 percent) experienced total flap loss, and one patient (6 percent) had partial flap loss requiring long-lasting wound treatment. Conclusions Outpatient free flap salvage has a low success rate regardless of flap type, recipient site, or patient population. The authors' study suggests that immediate second-line reconstruction is more effective for late-onset flap vascular crisis than extensive flap salvage procedures. Clinical question/level of evidence Therapeutic, V.

A significant percentage of patients who undergo segmental mandibulectomy for head and neck cancer will develop a new or recurrent cancer or osteoradionecrosis, necessitating a second mandibulectomy and reconstruction. In this scenario, many surgeons are reluctant to perform a reconstruction with an osseous flap because of the presumed increased morbidity and complexity. The purpose of this study was to evaluate the safety and efficacy of performing a second free fibula flap reconstruction after repeated segmental mandibulectomy.The authors retrospectively reviewed their prospectively maintained departmental database for mandible reconstructions performed between 1991 and 2016, identifying patients who had two sequential free fibula flap reconstructions. Patient, disease, and treatment characteristics were recorded and analyzed.Twenty patients underwent a second free fibula flap reconstruction after a second mandibulectomy. The median follow-up was 72.5 months (range, 16 to 243 months). Preoperative virtual planning was used more often for the second fibula flap compared with the first (50 percent versus 10 percent; p = 0.004). The mean operative times were statistically similar for the first versus second fibula flap (673 minutes versus 586 minutes, respectively; p = 0.13). The postoperative complication rates (50 percent versus 30 percent, respectively; p = 0.19) and functional outcomes were similar between the first and second fibula flap reconstructions.Despite the increased technical complexity, the use of a second free fibula flap after repeated segmental mandibulectomy appears to be safe and to confer no higher risk than that for the first fibula flap.Therapeutic, IV.

Postoperative hematoma and venous congestion after free tissue transfer may occur independently or concurrently. We aimed to explore the association between these two events.All free flap reconstructions for head and neck (HN) and breast from a single institution between 2004 and 2014 were retrospectively reviewed for reoperation for venous congestion and/or hematoma.There were 2985 free flap cases for HN reconstruction and 2345 cases for breast reconstruction. In HN, 100 patients developed a hematoma (3.4%) and 84 patients developed venous congestion (2.8%). The prevalence of hematoma was 17.8% and 2.9% in the presence and absence of congestion, respectively (p0.001). Among the 15 patients who had both hematoma and venous congestion were separate events that occurred from 1 to 9 days apart in 8 patients. Hematoma caused the compression of the pedicle vein in 4 patients, while venous congestion possibly caused hematoma in 3 patients. In breast, 56 patients developed a hematoma (2.4%) and 64 patients developed venous congestion (2.7%). The prevalence of hematoma was 12.5% and 2.1% in the presence and absence of congestion, respectively (p0.001). In the 8 patients who developed both, hematoma and congestion were separate events in 4 patients. Venous congestion caused hematoma in 3 patients, and hematoma caused venous congestion in 1 patient.Although postoperative hematoma and venous congestion often present concurrently, most events are not causally associated. When related, however, venous congestion leading to hematoma is more common in breast reconstruction, while hematoma preceding venous congestion is more common in HN reconstruction.

The iliac crest free flap, although the gold standard for many years for mandibular reconstruction, remains an important option in the armamentarium for mandibular reconstruction. With the increasing popularity of the fibula osteocutaneous flap, which allows for more refined reconstruction and permits multiple osteotomies, the iliac crest flap is typically reserved for where the fibula flap is contraindicated, including in those with peripheral vascular disease, peroneal magnum, history of fibula fractures, and with previous bilateral fibular flaps. The many limitations of the traditional osteomusculocutaneous flap have been overcome by modified approaches to harvest, including the split iliac crest based on the inner cortex to preserve the thigh muscle attachments and reduce donor site morbidity, and the deep circumflex iliac artery perforator flap that does not include the bulky abdominal wall musculature and allows greater freedom of movement of the skin paddle. This chapter reviews the indications, anatomy, surgical techniques, and postoperative management for the free iliac crest flap.

e18633 Background: The use of machine learning (ML) in plastic and reconstructive surgery has increased over the last decade. However, its use to predict surgical outcomes in head and neck reconstruction has not been well studied. The goal of this study is to assess the performance of ML algorithms trained to predict surgical outcomes of head and neck free flap reconstruction. Methods: Our study cohort included routinely collected data from 4000 patients who underwent free flaps for reconstruction of head and neck defects between January 2005 and December 2018. We developed and tested nine supervised ML algorithms to predict three outcomes of a.) any complication, b.) any major recipient-site complication, and c.) total flap loss. Results: In our sample, 33.7% of patients experienced any complication, 26.5% experienced a major complication at the recipient site and 1.7% experienced total flap loss. The k-nearest neighbors algorithm demonstrated the best overall performance for predicting any complication (AUROC = .61, sensitivity = .60). Regularized regression had the best performance for predicting major recipient site complication (AUROC=.68, sensitivity = .66), and decision trees were the best predictors of total flap loss (AUROC = .66, sensitivity = .50). Conclusions: We demonstrated that ML models trained using routinely collected data can make clinical useful predictions about who will experience complications. Our models correctly identified between half and two-thirds of patients who experienced post-surgical complications including total flap loss. These models can be applied to readily available clinical and perioperative data to facilitate decision making. Further performance improvements are likely possible with the inclusion of additional variables related to patient health and behavior.