Computer-aided assessment of bony nasal pyramid dimensions

OBJECTIVE

To develop a computer-enabled paradigm for assessment of bony nasal pyramid dimensions.

DESIGN

Retrospective review of archived computed tomographic data.

SETTING

Tertiary level academic center.

PATIENTS

Patients who had undergone computed tomographic scans for computer-aided transsphenoidal hypophysectomy were included. Previous nasal surgery, inflammatory sinus disease, and documented maxillofacial trauma were exclusion criteria.

INTERVENTION

Archived computed tomographic scan images were reviewed using the software tools on a computer-aided surgical (CAS) system (StealthStation; Sofamor Danek, Memphis, Tenn). Standardized methods for the measurement of nasal bone thickness and bony nasal pyramid projection were established.

MAIN OUTCOME MEASUREMENTS

Bony nasal pyramid projection and nasal bone thickness were determined.

RESULTS

Computed tomographic scans from 8 patients were reviewed. Nasal bone thickness at the level of lateral osteotomy was 2.39 +/- 0.68 (mean + SD) mm, while nasal bone thickness at the level of intermediate osteotomy was 1.18 + 0.30 mm. Nasal projection from the nasomaxillary suture to the rhinion in the axial plane was 19.20 + 3. 10 (mean + SD) mm, while the corresponding nasal projection at the nasion was 20.61 + 3.52 mm.

CONCLUSIONS

This brief report presents a new paradigm for the assessment of the bony nasal pyramid. Additional normative data are necessary. This information has important implications for rhinoplasty instrument design, surgical planning, and aesthetic assessment. It is likely that computer-enabled review of archived computed tomographic images for maxillofacial assessment will become increasingly accepted. Of course, further modifications of computer technology and its specific applications are expected.

Green light photoplethysmography monitoring of free flaps

BACKGROUND

Monitoring strategies have been developed to address the issue of detecting postoperative free flap ischemia in an effort to permit intervention and flap salvage. No one existing noninvasive method has been widely accepted in a clinical setting. Green light photoplethysmography (GLP) uses a diode to transmit green light into a tissue. Reflected light from hemoglobin in dermal capillary red blood cells is analyzed as light intensity along a frequency spectrum. A pure peak signal (1-2 Hz) is identified and provides a way to distinguish between perfused and nonperfused tissue.

DESIGN

Prospective, blinded comparison.

SUBJECTS

Sixty of 72 consecutive patients considered for free flap reconstruction were enrolled in a protocol to evaluate the efficacy of GLP.

INTERVENTION

After free flap elevation, but before pedicle ligation, 120-second baseline measurements were obtained; 120-second measurements then occurred 5 minutes after the onset or release of individual venous or arterial occlusion. Signals were processed by fast Fourier transfer; a mean alternating current-direct current (AC/ DC) ratio was cultivated for each signal. All data were analyzed in a blinded fashion.

RESULTS

The AC/DC ratio of GLP was statistically significant across all flap perfusion states (P<.001). Each condition resulted in a unique GLP signal within 5 minutes of manipulation of each vessel.

CONCLUSIONS

Green light photoplethysmography with AC/DC ratio analysis provides a rapid, precise method with which to determine flap ischemia and can differentiate venous compromised and arterial compromised flaps almost immediately after the onset of an ischemic insult. It may provide a clinically useful tool for postoperative free flap monitoring.

Surveillance for recurrent head and neck cancer using positron emission tomography

PURPOSE

Earlier detection of head and neck cancer recurrence may improve survival. We evaluated the ability of [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) to detect recurrence in a prospective trial using sequential PET scans.

PATIENTS AND METHODS

Serial posttherapy FDG-PET was prospectively performed in 44 patients with stage III or IV head and neck cancer. PET was performed twice during the first posttreatment year (at 2 and 10 months after therapy) and thereafter as needed. After therapy, patients were grouped, based on tissue biopsies, into those who achieved a complete response (CR) and those who had residual disease (RD). Patients who achieved a CR were further grouped into those without evidence of disease and those who had recurrence by 1 year after completion of therapy. Disease status as determined by physical examination (PE), PET, and correlative imaging was compared.

RESULTS

Eight patients were lost to follow-up and six had RD after therapy. Of the remaining 30 patients with a CR, 16 had recurrence in the first year after therapy. Five of these 16 patients had recurrence detected by PET only, four by PET and correlative imaging only, five by PE and PET only, and two by PE, correlative imaging, and PET. Only PET detected all recurrences in the first year. PET performed better than correlative imaging (P =.013) or PE (P =.002) in the detection of recurrence.

CONCLUSION

PET can detect head and neck tumor recurrence when it may be undetectable by other clinical methods. FDG-PET permits highly accurate detection of head and neck cancer recurrence in the posttherapy period.