Airway Volume Simulation in Virtual Mandibular Distraction: A Cohort Study.

BACKGROUND: The authors investigated the accuracy of virtual surgical planning in predicting airway volume changes after mandibular distraction in patients with Pierre Robin sequence and associated tongue-based airway obstruction. METHODS: The authors completed a single-institution retrospective review of patients for whom virtual surgical planning was used during mandibular distraction osteogenesis for treatment of tongue-based airway obstruction. Preoperative airway volume, virtual surgical planning-predicted airway volume, and postoperative airway volume were calculated from three-dimensional computed tomographic scans using industry software. A blinded institutional radiologist also calculated pre- and post-operative airway volumes. Pre- and post-operative polysomnography was used to titrate the endpoint of mandibular lengthening. RESULTS: Eleven patients were included in the study. Mean apnea-hypopnea index (5.42 ± 4.53 versus 44.96 ± 20.57; p < 0.001) and mean nadir oxygen saturation (70.3 ± 9.72 percent versus 82.9 ± 9.62 percent; p = 0.003) improved with mandibular distraction. There was moderate correlation between predicted and actual mandibular distraction lengths (R = 0.65; p = 0.003). There was a strong correlation between predicted and industry-calculated actual post-distraction airway volume (R = 0.99; p < 0.001). There was no significant correlation between actual mandibular distraction length and industry-calculated actual post-distraction airway volume for the entire cohort (R = 0.05; p = 0.49), but correlation approached significance by institutional calculations. No significant correlation existed between industry and institutional-calculated percentage change in post-distraction airway volume (R = 0.06; p = 0.57). CONCLUSIONS: Predictive airway volume calculation may be an effective adjunct to determine anatomic endpoint of mandibular distraction but small sample size, operator and software variability, and patient airway morphology may confound firm conclusions. Further studies are warranted.

Does Mandibular Distraction Vector Influence Airway Volumes and Outcome?

PURPOSE: The goal of mandibular distraction in the Pierre-Robin sequence is to maximally expand the oropharyngeal airway. It has been hypothesized that a steep oblique distraction vector might allow greater airway enlargement compared with horizontal distraction. This study compared vector orientation in relation to airway volume and overall clinical outcome. MATERIALS AND METHODS: Micrognathic infants who underwent mandibular distraction with sufficient computed tomographic data were retrospectively reviewed. Demographic, diagnostic, perioperative, and distraction data were recorded. Groups were separated based on distraction vector (group 1, horizontal; group 2, oblique). Airway and mandibular volumes were measured using Mimics (Materialise, Leuven, Belgium). Morphologic and outcomes data were analyzed. Statistics involved 2-tailed t test, Pearson correlation, and analysis of covariance (ANCOVA). RESULTS: Mean age at distraction was 40 days, with devices maintained for 82 days on average. Fifty percent of patients were girls and 65% had cleft palate. Forty computed tomograms were analyzed. Airway (1,234 vs 3,501 mm3; P < .01) and mandibular (5,457 vs 11,827 mm3; P < .01) volumes, minimal airway area (12.5 vs 63.7 mm2; P < .01), and posterior airway space distance (2.3 vs 9.8 mm; P = .04) were significantly increased after distraction. Patients also had clinically improved sleep studies after distraction (apnea hypopnea index, 51.3 vs 5.5; P < .01). Vector analysis showed an average of 5.3° and 14.0° in groups 1 and 2, respectively (n = 10 each). Intergroup analysis showed a trend toward increased airway volume in horizontal vectors (548 vs 255% of preoperative volume; P = .058), with slightly longer distraction length (20.3 vs 16.6 mm; P = .17). However, ANCOVA regression analysis showed no difference in the relation between vector and length. Other morphologic data and sleep study outcomes (apnea hypopnea index, 7.0 vs 3.9; P = .09) also were not statistically different between groups. Longer lengths of distraction correlated with narrower anterior mandibular angle and longer mandibular body length. CONCLUSIONS: Substantial airway enlargement occurs after mandibular distraction. Final airway volumes were similar between groups regardless of vector, which was confirmed by multivariate ANCOVA regression. The 2 methods achieved airway stabilization, with clinical outcomes similar between the 2 groups.

Standardization of Disposable Instruments in Microvascular Breast Reconstruction: A Case Study in Cost Reduction.

Background A key avoidable expense in the surgical setting is the wastage of disposable surgical items, which are discarded after cases even if they go unused. A major contributor to wastage of these items is the inaccuracy of surgeon preference cards, which are rarely examined or updated. The authors report the application of a novel technique called cost heatmapping to facilitate standardization of preference cards for microvascular breast reconstruction. Methods Preference card data were obtained for all surgeons performing microvascular breast reconstruction at the authors' institution. These data were visualized using the heatmap.2 function in the gplot package for R. The resulting cost heatmaps were shown to all surgeons performing microvascular breast reconstruction at our institution; each surgeon was asked to classify the items on the heatmap as "always needed," "sometimes needed," or "never needed." This feedback was used to generate a lean standardized preference card for all surgeons. This card was validated by all surgeons performing the case and by nursing leadership familiar with the supply needs of microvascular breast reconstruction before implementation. Cost savings associated with implementation were calculated. Results Implementation of the preference card changes will lead to an estimated per annum savings of $17,981.20 and a per annum reduction in individual items listed on preference cards of 1,693 items. Conclusion Cost heatmapping is a powerful tool for increasing surgeon awareness of cost and for facilitating comparison and standardization of surgeon preference cards.

Breast Reconstruction with SIEA Flaps: A Single-Institution Experience with 145 Free Flaps.

BACKGROUND: Refinements in microsurgical breast reconstruction have refined superficial inferior epigastric artery (SIEA) and superficial circumflex iliac artery (SCIA) flaps, yet technical difficulties and varied success rates limit widespread acceptance. The authors present the outcomes of their experience with 145 consecutive SIEA/SCIA flaps and suggest technical tips to improve success with this important flap. METHODS: An institutional review board-approved retrospective chart review of all SIEA/SCIA free flaps performed by the senior authors between January 1, 2006, and February 6, 2014, was conducted. Data on patient demographics, flap characteristics, and complications were collected. RESULTS: There were 145 flaps performed in 119 patients. Arterial donor and recipient mismatch occurred in 55 instances (38 percent). In these cases, 48 arteries (87 percent) were spatulated and seven (13 percent) were back-cut to improve size concordance. Nine flaps required operative return for flap viability concerns. Five were arterial, three were venous, and one flap had concomitant arterial and venous thrombosis. Total flap loss rate attributable to thrombotic events was 4.8 percent. No flaps with arterial thrombosis on reoperation were salvageable. Furthermore, 80 percent had arterial revisions at initial operation. No patients had an abdominal bulge or hernia, and the fat necrosis rate was 10.3 percent. CONCLUSIONS: SIEA/SCIA breast reconstruction can be reliably performed; however, flaps exhibiting postoperative arterial thrombosis with revision at initial surgery are unlikely salvageable on reoperation. Spatulation did not correlate with an increased thrombosis rate; in fact, the authors advocate for donor artery manipulation to manage size mismatch. CLINCAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Predictive Soft Tissue Airway Volume Analysis in Mandibular Distraction: Pushing The Envelope in Surgical Planning for Obstructive Sleep Apnea.

Three-dimensional computed tomography has been used in both preoperative planning of mandibular distraction osteogenesis and in the evaluation of postoperative resolution of tongue-based airway obstruction. The authors present a case report using software to predict postdistraction airway volume during virtual surgical planning (VSP) of mandibular distraction osteogenesis in a 7 year old. The predicted increase in airway volume derived from VSP was 33.57% (1716 mm(3) preoperatively to 2292 mm(3) postvirtual distraction). Based on the three-dimensional computed tomography, the actual airway volume increased to 2211 mm(3) postoperatively, a 28.85% increase.The implications of this advancing technology are far-reaching. An illustrative case is presented herein to demonstrate the efficacy of the airway prediction and its limitations. The authors believe that, with continued investigation, this novel approach may be a standard feature of all VSP sessions for the treatment of tongue-based airway obstruction.