E. Bradley Strong

Computer modeling and intraoperative navigation in maxillofacial surgery

Objectives Recent advances in computer-modeling software allow reconstruction of facial symmetry in a virtual environment. This study evaluates the use of preoperative computer modeling and intraoperative navigation to guide reconstruction of the max-illofacial skeleton. Methods Three patients with traumatic maxillofacial deformities received preoperative, thin-cut axial CT scans. Three-dimensional reconstructions, virtual osteotomies, and bony reductions were performed using MIMICS planning software (Materialise, Ann Arbor, MI). The original and “repaired” virtual datasets were then imported into an intraoperative navigation system and used to guide the surgical repair. Results Postoperative CT scans and photographs reveal excellent correction of enophthalmos to within 1 mm in patient 1, significant improvement in symmetry of the nasoethmoid complex in patient 2, and reconstruction of the zygomaticomaxillary complex location to within 1 mm in patient 3. Conclusion Computer modeling and intraoperative navigation is a relatively new tool that can assist surgeons with reconstruction of the maxillofacial skeleton.

Comparison of 3 Optical Navigation Systems for Computer-Aided Maxillofacial Surgery

OBJECTIVE To compare the accuracy of 3 computer-aided surgery systems for maxillofacial reconstruction. DESIGN Evaluation of 3 computer-aided surgery systems: StealthStation, VectorVision, and Voxim. SETTING The University of California, Davis, Department of Otolaryngology computer-aided surgery laboratory. PARTICIPANTS Four fresh cadaveric heads. MAIN OUTCOME MEASURE Mean target registration error. RESULTS The StealthStation was the most accurate (mean [SD] target registration error, 1.00 [0.04] mm), followed by VectorVision (1.13 [0.05] mm) and then Voxim (1.34 [0.04] mm). All values met statistical significance (P < .05). CONCLUSIONS Measurable accuracy differences were found among the navigation systems evaluated. The StealthStation was the most accurate. However, the differences are small, and the clinical significance for maxillofacial reconstruction is negligible.

Intractable Epistaxis: Transantral Ligation vs. Embolization: Efficacy Review and Cost Analysis

After posterior nasal packing, the two most common therapies for intractable epistaxis are transantral ligation of the internal maxillary artery and percutaneous embolization of the distal internal maxillary artery. However, optimal management of intractable posterior epistaxis remains controversial. We retrospectively reviewed the charts of 21 patients treated for intractable epistaxis and obtained data on presentation, risk factors, treatment, success rates, complications, and cost. Twelve patients received percutaneous embolization, five underwent transantral ligation, and four required both. The success rates for transantral ligation and percutaneous embolization were 89% and 94%, respectively. No mortality or serious morbidity occurred with either technique. A cost comparison revealed that transantral ligation was moderately less expensive than percutaneous embolization (

Pathologic Analysis of Routine Tonsillectomy and Adenoidectomy Specimens

5941 vs.

Endoscopic Approach to Orbital Blowout Fracture Repair

6783). Although some authors advocate transantral ligation or percutaneous embolization as the procedure of choice for intractable epistaxis, a direct comparison of efficacy and cost reveals that they are comparable procedures with specific strengths and weaknesses. We present our experience and a review of the literature, highlighting the indications and advantages of each technique. We conclude that the choice of treatment modality should be based on the benefits of each procedure as it pertains to the specific needs of the individual patient.

Frontal sinus fractures: a 28-year retrospective review

OBJECTIVES: Recent literature has suggested that histopathologic analysis of routine tonsillectomy and adenoidectomy (T&A) specimens may be unnecessary. This study investigates T&A specimen handling practices in the United States between 1989 and 1999. METHODS: Surveys were sent to 4715 members of the American Academy of Otolaryngology. Surveys assessed practice type, pathologic processing practices (full, gross, no pathology), and reasons for change. The authors also performed a retrospective analysis of 1583 pediatric T&A specimens for evidence of occult malignancy. RESULTS: Practice types were 80% private, 12% academic, 6% salaried, and 2% military. Chi squared analysis revealed a significant increase (P < 0.001) in respondents ordering “gross only” and “no pathology.” The retrospective analysis found no occult malignancies. CONCLUSIONS: There is a statistically significant increase in the number of otolaryngologists sending routine T&A specimens for “gross only” and “no pathology.” There was no correlation between the type of practice and changes in pathologic analysis performed.

Endoscopic management of facial fractures.

OBJECTIVES: Transconjunctival and subciliary approaches to orbital floor blowout fractures (OBF) have known risks of postoperative eyelid malposition. This study evaluates the endoscopic transmaxillary repair of OBFs in a cadaveric model and clinical setting. METHODS: Sixteen cadaveric and 10 clinical OBFs were repaired endoscopically. A Caldwell-Luc approach and modified sinus surgery instrumentation were used to repair each fracture. Variations in fracture pattern, instrumentation, and surgical technique were evaluated. RESULTS: Endoscopic repair was achieved in all 16 cadaveric orbits and in 9 of 10 patients. Fracture patterns were classified as either medial or lateral to the infraorbital nerve. Average clinical operating time was 1:38. Of 9 postoperative CT scans, 5 were rated as excellent, 3 as good, and 1 as poor. CONCLUSIONS: The endoscopic transmaxillary approach is a safe, viable technique for OBF repair. It offers improved visualization, anatomic fracture repair, no risk of postoperative eyelid complications, and good clinical results. EBM rating: C.

Linear and angular measurements of computer-generated models: Are they accurate, valid, and reliable?

OBJECTIVES: To analyze 202 consecutive frontal sinus fracture (FSF) patients treated between 1974 and 2002 at the University of California, Davis. METHODS: A retrospective chart review was performed, including all patients with frontal sinus fractures from 1987 to 2002. This and 72 previously reported patients (1974-1986) were analyzed, comparing age, gender, fracture type, associated fractures, procedure type, and complications. RESULTS: Frontal sinus fractures resulting from motor vehicle accidents (MVAs) decreased from 71% to 52% (P < 0.05). Fractures from assaults increased from 9% to 21% (P < 0.05). The incidence of “through and through” fractures decreased from 40% to 11% (P < 0.05). Whereas combined anterior/posterior table fractures increased from 36% to 57% (P < 0.05). CONCLUSION: The etiology and severity of FSF has changed from 1974 to 2002. This is reflected in a reduced number of fractures resulting from MVAs as well as a reduced severity of injury. The most likely explanation is the use of safety belts and airbags.

Computer applications in facial plastic and reconstructive surgery

Purpose of reviewEndoscopic applications in otolaryngology continue to expand, most recently in the area of maxillofacial trauma. Endoscopic management of orbital blow-out, frontal sinus, zygomatic arch, and subcondylar fractures has been described. This paper reviews the current literature including new techniques, indications, and outcomes in endoscopic management of facial fractures. Recent findingsVery few large studies of endoscopic fracture repair exist. The current literature, however, suggests that, when compared with an open approach, smaller endoscopic incisions result in reduced patient morbidity with similar outcomes. Dedicated endoscopic instrumentation and novel surgical approaches continue to be developed. SummaryEndoscopic repair of facial fractures is a new and evolving technique that offers the potential for reduced patient morbidity and operating time, as well as quicker patient recovery. Current applications include the management of orbital blow-out, frontal sinus, zygomatic arch, and subcondylar fractures. It should be emphasized that endoscopy augments, rather than replaces, the ‘time tested’ principles of adequate skeletal exposure, accurate fracture reduction, and appropriate internal fixation.

Endoscopic repair of anterior table: Frontal sinus fractures with a medpor implant

INTRODUCTION Traditional advanced imaging modalities such as CT and MRI are limited in their ability to perform accurate linear distance and angular measurements regardless of anatomical orientation. The construction of 3D models has been used to perform anthropometric analyses as well as in the reconstruction of rapid prototypes. We hypothesized that such measurements would be precise to within 2 mm or 2 degrees of measurements performed with a coordinate measurement machine (CMM). We also hypothesized that there would be a high degree of interobserver reliability with these measurements. MATERIALS AND METHODS Multiple aluminum screws were implanted in various positions in three foam pelvises which were subsequently scanned by CT and rendered as 3D models using a commercially available software package (Mimics). Linear and angular measurements were performed using a CMM machine, the software package, and a dial caliper or goniometer. The deviation of the measurements from the CMM data was compared using ANOVA. The interobserver reliability of both the manual and computer-generated measurements was calculated. RESULTS The mean difference between the CMM distances and those measured manually and with the software was 2.12 +/- 1.20 mm and 1.57 +/- 1.05 mm, respectively. The mean difference between the CMM angular measurements and the angular measurements performed manually and with the software was 4.07 +/- 4.70 degrees and 1.62 +/- 1.32 degrees, respectively. In all cases, the manual measurements were significantly less accurate (p < 0.0001) and there was a high degree of interobserver reliability. CONCLUSIONS Computer-generated measurements taken from three-dimensionally reconstructed models are more accurate than manual measurements and are within 2 mm and 2 degrees of measurements performed with a CMM. These measurements have high interobserver reliability.