Edward W. Swanson

Craniofacial reconstruction with poly(methyl methacrylate) customized cranial implants.

BackgroundSecondary cranioplasty with customized craniofacial implants (CCIs) are often used to restore cerebral protection and reverse syndromes of the trephined, and for reconstruction of acquired cranial deformities. The 2 most widely used implant materials are polyetheretherketone and poly(methylmethacrylate) (PMMA). Previous series with CCIs report several major complications, including implant infection leading to removal, extended hospital stays, and surgical revisions. With this in mind, we chose to review our large case series of 22 consecutive PMMA CCI cranioplasties treated by a single craniofacial surgeon. MethodsA cohort of 20 consecutive patients receiving 22 PMMA implants during a 2-year period was identified and outcomes reviewed. The mechanism of initial insult, time from craniectomy to cranioplasty, anesthesia time, major and minor postoperative complications, radiation history, and length of follow-up were statistically analyzed. ResultsThere were no complications related to infection, hematoma/seroma, or cerebrospinal fluid leak (0/22, 0%). Two patients experienced major complications related to persistent temporal hollowing (PTH) following standard CCI cranioplasty, which required revision surgery with modified implants (2/22, 9%). One minor complication of self-resolving transient diplopia was noted (1/22, 5%). ConclusionsIn this consecutive series, PMMA CCIs were associated with a very low complication rate, suggesting that PMMA may be a preferred material for CCI fabrication. However, with 10% (2/20) of patients experiencing PTH and dissatisfaction related to asymmetry, future research must be directed at modifying CCI shape, to address the overlying soft-tissue deformity. If successful, this may increase patient satisfaction, prevent PTH, and avoid additional costs of revision surgery.

Quantitative analysis of dual-purpose, patient-specific craniofacial implants for correction of temporal deformity

BACKGROUND: The development of computer-assisted design, virtual modeling, and computed tomography has allowed precise customization of implants for patients who undergo neurosurgical or craniofacial surgery procedures. However, such techniques and implant designs have not adequately addressed temporal asymmetry due to postoperative bone resorption, temporalis muscle malposition/foreshortening, and/or temporal fat pad atrophy. OBJECTIVE: We hypothesized that an alteration in customized craniofacial implant (CCI) design with a strategic extension inferolaterally and excessive material bulking would provide simultaneous reconstruction of coexisting temporal skull defects and therefore reduce the effect of soft tissue deformities. METHODS: A single-surgeon, single-institution retrospective cohort study was performed to include 10 consecutive subjects who underwent cranioplasty reconstruction with modified implants during a 3-year period. Implants were placed with the use of our previously described pericranial-onlay technique. With the use of a computed tomography-based, computer-assisted design/manufacturing methodology, novel dual-purpose implants were designed to prevent and/or correct persistent temporal hollowing. The efficacy of the new CCI shape and design for cranial restoration of temporal symmetry was analyzed in both 2 and 3 dimensions. RESULTS: In 2-dimensional analyses, the modified implant provided enhanced lateral projection (21%; 1.06 cm) in areas closest to the temporal arch. Three-dimensional volumetric analyses demonstrated that additional bulking totaled 24 ± 11 cm3 (range, 9-43 cm3), which essentially replaced 40 ± 13.7% (range, 26%-60%) of the absent temporal volume contributing to persistent temporal hollowing. CONCLUSION: Computer-designed, dual-purpose CCIs can be safely created with unprecedented shape to prevent and/or eradicate postoperative temporal deformity. ABBREVIATIONS: CAD, computer-assisted design CAM, computer-assisted manufacturing CCI, customized craniofacial implant PEEK, poly(ether ether ketone) PMMA, poly(methyl methacrylate) PTH, persistent temporal hollowing

Preliminary development of a workstation for craniomaxillofacial surgical procedures: introducing a computer-assisted planning and execution system.

IntroductionFacial transplantation represents one of the most complicated scenarios in craniofacial surgery because of skeletal, aesthetic, and dental discrepancies between donor and recipient. However, standard off-the-shelf vendor computer-assisted surgery systems may not provide custom features to mitigate the increased complexity of this particular procedure. We propose to develop a computer-assisted surgery solution customized for preoperative planning, intraoperative navigation including cutting guides, and dynamic, instantaneous feedback of cephalometric measurements/angles as needed for facial transplantation and other related craniomaxillofacial procedures. MethodsWe developed the Computer-Assisted Planning and Execution (CAPE) workstation to assist with planning and execution of facial transplantation. Preoperative maxillofacial computed tomography (CT) scans were obtained on 4 size-mismatched miniature swine encompassing 2 live face-jaw-teeth transplants. The system was tested in a laboratory setting using plastic models of mismatched swine, after which the system was used in 2 live swine transplants. Postoperative CT imaging was obtained and compared with the preoperative plan and intraoperative measures from the CAPE workstation for both transplants. ResultsPlastic model tests familiarized the team with the CAPE workstation and identified several defects in the workflow. Live swine surgeries demonstrated utility of the CAPE system in the operating room, showing submillimeter registration error of 0.6 ± 0.24 mm and promising qualitative comparisons between intraoperative data and postoperative CT imaging. ConclusionsThe initial development of the CAPE workstation demonstrated that integration of computer planning and intraoperative navigation for facial transplantation are possible with submillimeter accuracy. This approach can potentially improve preoperative planning, allowing ideal donor-recipient matching despite significant size mismatch, and accurate surgical execution for numerous types of craniofacial and orthognathic surgical procedures.

The Association of the H-Index and Academic Rank Among Full-Time Academic Hand Surgeons Affiliated With Fellowship Programs

PURPOSE To evaluate the association between the Hirsch index (a measure of publications and citations) and academic rank among hand surgeons. METHODS This was a cross-sectional study of full-time academic hand surgeons within Accreditation Council for Graduate Medical Education-approved hand surgery fellowship programs in the United States and Canada. The study variables were classified as bibliometric (h-index, I-10 index, total number of publications, total number of citations, maximum number of citations for a single work) and demographics (gender, training factors). The outcome was academic rank (instructor, assistant professor, associate professor, professor, endowed professor). Descriptive, bivariate, and multiple regression statistics were computed. RESULTS The sample was composed of 366 full-time academic hand surgeons; 86% were male and 98% had formal hand surgery fellowship training. The mean time since completion of surgical training was 17 ± 11 years. The distribution of primary faculty appointments was orthopedic surgery (70%) and plastic surgery (30%). Two hundred fifty surgeons (68%) were members of the American Society for Surgery of the Hand. The mean h-index was 10.2 ± 9.9 and was strongly correlated with academic rank. Gender was not associated with academic rank. Distribution of academic ranks was as follows: instructor (4%), assistant professor (28%), associate professor (40%), professor (22%), and endowed professor (5%). The h-index, years since completion of training, and American Society for Surgery of the Hand membership were associated with academic rank. The h-index had a high sensitivity and specificity for predicting academic rank. CONCLUSIONS The h-index is a reliable tool for quantitatively assessing research productivity and should be considered for use in academic hand surgery. CLINICAL RELEVANCE When evaluating candidates for academic promotion in hand surgery, the h-index is a potentially valuable tool for assessing research productivity and impact.

Craniomaxillofacial reconstruction using allotransplantation and tissue engineering: challenges, opportunities, and potential synergy.

The face is composed of an intricate underlying bony/cartilaginous framework that supports muscle, secretory organs, and sophisticated skin/subcutaneous structures. These components are attached through numerous ligaments and interact dynamically with a vast neurovascular network. The most sophisticated autologous reconstructive techniques, utilizing composite free-tissue flaps, are often inadequate to restore extensive maxillofacial defects. Massive craniomaxillofacial (CMF) defects resulting from trauma, oncologic resection, or congenital deformity present a unique challenge to reconstructive surgeons. Therefore, recent advances in craniofacial surgery and immunotherapy spurred the innovation of composite tissue allotransplantation (CTA), which permits reconstruction with tissue composed of all necessary components. However, CMF allotransplantation carries with it side effects of lifelong immunosuppression. Furthermore, the donor skeletal framework may not provide an ideal match, resulting in less than ideal occlusion and soft-tissue anthropometrics. An alternative to transplantation, tissue engineering, has provided hope for regenerating missing tissue and avoiding the need for immunosuppression. Many tissue subtypes, including bone and cartilage, have been successfully created, with sparse reports of clinical application. Tissue-engineered composite tissue required for complete CMF reconstruction continues to elude development, with vascular supply and tissue interactions posing the largest remaining obstacles. We report herein the current status and limitations of CTA and tissue engineering. Furthermore, we describe for the first time our vision of hybridization of CTA and engineering, utilizing the strengths of each strategy.

Overcoming cross-gender differences and challenges in Le Fort-based, craniomaxillofacial transplantation with enhanced computer-assisted technology.

BackgroundSex-specific anthropometrics, skin texture/adnexae mismatch, and social apprehension have prevented cross-gender facial transplantation from evolving. However, the scarce donor pool and extreme waitlist times are currently suboptimal. Our objective was to (1) perform and assess cadaveric facial transplantation for each sex-mismatched scenario using virtual planning with cutting guide fabrication and (2) review the advantages/disadvantages of cross-gender facial transplantation. MethodsCross-gender facial transplantation feasibility was evaluated through 2 mock, double-jaw, Le Fort–based cadaveric allotransplants, including female donor-to-male recipient and male donor-to-female recipient. Hybrid facial-skeletal relationships were investigated using cephalometric measurements, including sellion-nasion-A point and sellion-nasion-B point angles, and lower-anterior-facial-height to total-anterior-facial-height ratio. Donor and recipient cutting guides were designed with virtual planning based on our team’s experience in swine dissections and used to optimize the results. ResultsSkeletal proportions and facial-aesthetic harmony of the transplants (n = 2) were found to be equivalent to all reported experimental/clinical sex-matched cases by using custom guides and Mimics technology. Cephalometric measurements relative to Eastman Normal Values are shown. ConclusionsOn the basis of our results, we believe that cross-gender facial transplantation can offer equivalent, anatomical skeletal outcomes to those of sex-matched pairs using preoperative planning and custom guides for execution. Lack of literature discussion of cross-gender facial transplantation highlights the general stigmata encompassing the subject. We hypothesize that concerns over sex-specific anthropometrics, skin texture/adnexae disparity, and increased immunological resistance have prevented full acceptance thus far. Advantages include an increased donor pool with expedited reconstruction, as well as size-matched donors.

Patient Transport and Brain Oxygen in Comatose Patients

OBJECTIVETransport of critically ill intensive care unit patients may be hazardous. We examined whether brain oxygen (brain tissue oxygen partial pressure [PbtO2]) is influenced by transport to and from a follow-up head computed tomography (transport head computed tomography [tHCT]) scan. METHODSForty-five patients (24 men, 21 women; Glasgow Coma Scale score ≤8; mean age, 47.3 ± 19.0 years) who had a traumatic brain injury (n = 26) or subarachnoid hemorrhage (n = 19) were retrospectively identified from a prospective observational cohort of PbtO2 monitoring in a neurosurgical intensive care unit at a university-based level I trauma center. PbtO2, intracranial pressure, and cerebral perfusion pressure were monitored continuously and compared during the 3 hours before and after 100 tHCT scans. RESULTSThe mean PbtO2 before and after the tHCT scans for all 100 scans was 37.9 ± 19.8 mm Hg and 33.9 ± 17.2 mm Hg, respectively (P = .0001). A decrease in PbtO2 (>5%) occurred after 54 tHCTs (54%) and in 36 patients (80%). In instances in which a decrease occurred, the average decrease in mean, minimum, and maximum PbtO2 was 23.6%, 29%, and 18.1%, respectively. This decrease was greater when PbtO2 was compromised (<25 mm Hg) before tHCT. An episode of brain hypoxia (<15 mm Hg) was identified in the 3 hours before tHCT in 9 and after tHCT in 19 instances. On average, an episode of brain hypoxia was 46.6 ± 16.0 (standard error) minutes longer after tHCT than before tHCT (P = .008). Multivariate analysis suggests that changes in lung function (PaO2/fraction of inspired oxygen [FiO2] ratio) may account for the reduced PbtO2 after tHCT (parameter estimate 0.45, 95% confidence interval: 0.024–0.871; P = .04). CONCLUSIONThese data suggest that transport to and from the intensive care unit may adversely affect PbtO2. This deleterious effect is greater when PbtO2 is already compromised and may be associated with lung function.

A modification of the facial artery musculomucosal flap for palatal reconstruction in patients with intact dentition.

Since its description in 1992, the facial artery musculomucosal flap has become a valuable option in regional reconstruction of midface defects.1 Current indications include reconstruction of palate, floor-of-mouth, nasal, and vermilion defects.2– 6 Advantages over other regional flaps include its axial blood supply permitting extended length, minimal donor-site morbidity, and flexibility to have either a superior or inferior pedicle. Despite its usefulness, the main limitation of this flap is its inability to be easily tunneled for palatal reconstruction in patients with intact dentition (Fig. 1). These patients must wear a bite block to avoid chewing on the pedicle, and they require a second procedure for flap division. This report describes a modification of the inferiorly based facial artery musculomucosal flap that allows single-stage reconstruction for patients with intact dentition.

Surgical Resection Versus Palliative Chemoradiotherapy for the Management of Pancreatic Cancer with Local Venous Invasion: A Decision Analysis

BackgroundBenefit from pancreaticoduodenectomy (PD) combined with superior mesenteric-portal vein (SMV-PV) resection in the management of pancreatic adenocarcinoma with local venous invasion remains controversial.MethodsUsing formal decision analysis, we compared survival associated with PD plus SMV-PV resection when applied to patients with pancreatic adenocarcinoma with isolated local venous invasion (Group 1) versus that achieved with palliative chemoradiotherapy when applied to patients with locally advanced pancreatic cancer (Group 2). Individual studies were identified using Medline. A total of 1,324 and 709 patients were analyzed for Groups 1 and 2, respectively. Patients with distant metastases were excluded.ResultsOverall decision analysis favored surgical resection (Group 1) over palliative chemoradiotherapy (Group 2). Sensitivity analyses indicated that this decision is sensitive to the perioperative mortality rate and the percentage of surgical resections with microscopic (R1) or macroscopic (R2) residual tumor at the resection margin. In contrast, sensitivity analysis revealed that the decision is not sensitive to the percentage of cases in which true venous invasion by cancer is documented histologically.ConclusionsSurgical resection may confer a survival advantage over palliative chemoradiotherapy in select patients with pancreatic cancers with presumed local venous invasion.

Are quantitative measures of academic productivity correlated with academic rank in plastic surgery? A national study

Background: The purpose of this study was to investigate the correlation between quantitative measures of academic productivity and academic rank among full-time academic plastic surgeons. Methods: Bibliometric indices were computed for all full-time academic plastic surgeons in the United States. The primary study variable was academic rank. Bibliometric predictors included the Hirsch index, I-10 index, number of publications, number of citations, and highest number of citations for a single publication. Descriptive, bivariate, and correlation analyses were computed. Multiple comparisons testing was used to calculate adjusted associations for subgroups. For all analyses, a value of p < 0.05 was considered significant. Results: The cohort consisted of 607 plastic surgeons across 91 Accreditation Council for Graduate Medical Education–approved programs. Of them, 4.1 percent were instructors/lecturers, 43.7 percent were assistant professors, 22.1 percent were associate professors, 25.7 percent were professors, and 4.4 percent were endowed professors. Mean values were as follows: Hirsch index, 10.2 ± 9.0; I-10 index, 17.2 ± 10.2; total number of publications, 45.5 ± 69.4; total number of citations, 725.0 ± 1448.8; and highest number of citations for a single work, 117.8 ± 262.4. Correlation analyses revealed strong associations of the Hirsch index, I-10 index, number of publications, and number of citations with academic rank (rs = 0.62 to 0.64; p < 0.001). Conclusions: Academic rank in plastic surgery is strongly correlated with several quantitative metrics of research productivity. Although academic promotion is the result of success in multiple different areas, bibliometric measures may be useful adjuncts for assessment of research productivity.