Daniel E. Cannon

Role of Virtual Surgery in Preoperative Planning: Assessing the Individual Components of Functional Nasal Airway Surgery

OBJECTIVES To demonstrate the effect of individual components of functional nasal airway surgery in a patient with multifactorial obstruction and to discuss the potential benefit of computational fluid dynamics (CFD)–aided virtual surgery. METHODS A 53-year-old woman underwent septoplasty,turbinate reduction, and nasal valve repair. Presurgery and postsurgery digital nasal models were created from computed tomographic images, and nasal resistance was calculated using CFD techniques. The digital models were then manipulated to isolate the effects of the components of the surgery, creating a nasal valverepair alone model and a septoplasty/turbinate reduction alone model. RESULTS Bilateral nasal resistance in the postsurgery model was approximately 25% less than presurgery values.Similarly, CFD analysis showed reductions in nasal resistance of the virtual models: 19% reduction with intranasal surgery alone and 6% reduction with nasal valve repair alone. CONCLUSIONS Most of the reduction in nasal resistance was accomplished with performance of septoplasty and inferior turbinate reduction. The contribution of nasal valve repair was less in comparison but not insignificant.This pilot study implies that CFD-aided virtual surgery may be useful as part of preoperative planning inpatients with multifactorial anatomical nasal airwayobstruction

Computed nasal resistance compared with patient-reported symptoms in surgically treated nasal airway passages: a preliminary report.

Background Nasal airway obstruction (NAO) is a common health condition impacting mood, energy, recreation, sleep, and overall quality of life. Nasal surgery often addresses NAO but the results are sometimes unsatisfactory. Evaluating surgical treatment efficacy could be improved if objective tests were available that correlated with patient-reported measures of symptoms. The goal of this study was to develop methods for comparing nasal resistance computed by computational fluid dynamics (CFD) models with patient-reported symptoms of NAO using early data from a 4-year prospective study. Methods Computed tomography (CT) scans and patient-reported scores from the Nasal Obstruction Symptom Evaluation (NOSE) scale and a visual analog scale (VAS) measuring unilateral airflow sensation were obtained pre- and postoperatively in two NAO patients showing no significant mucosal asymmetry who were successfully treated with functional nasal surgery, including septoplasty. Pre- and postsurgery CFD models were created from the CT scans. Numerical simulation of steady-state inspiratory airflow was used to calculate bilateral and unilateral CFD-derived nasal resistance (CFD-NR). Results In both subjects, NOSE and VAS scores improved after surgery, bilateral CFD-NR decreased, and unilateral CFD-NR decreased on the affected side. In addition, NOSE and VAS scores tracked with unilateral CFD-NR on the affected side. Conclusion These preliminary results suggest a possible correlation between unilateral NR and patient-reported symptoms and imply that analysis of unilateral obstruction should focus on the affected side. A formal investigation of unilateral CFD-NR and patient-reported symptoms in a series of NAO patients is needed to determine if these variables are correlated.BACKGROUND Nasal airway obstruction (NAO) is a common health condition impacting mood, energy, recreation, sleep, and overall quality of life. Nasal surgery often addresses NAO but the results are sometimes unsatisfactory. Evaluating surgical treatment efficacy could be improved if objective tests were available that correlated with patient-reported measures of symptoms. The goal of this study was to develop methods for comparing nasal resistance computed by computational fluid dynamics (CFD) models with patient-reported symptoms of NAO using early data from a 4-year prospective study. METHODS Computed tomography (CT) scans and patient-reported scores from the Nasal Obstruction Symptom Evaluation (NOSE) scale and a visual analog scale (VAS) measuring unilateral airflow sensation were obtained pre- and postoperatively in two NAO patients showing no significant mucosal asymmetry who were successfully treated with functional nasal surgery, including septoplasty. Pre- and postsurgery CFD models were created from the CT scans. Numerical simulation of steady-state inspiratory airflow was used to calculate bilateral and unilateral CFD-derived nasal resistance (CFD-NR). RESULTS In both subjects, NOSE and VAS scores improved after surgery, bilateral CFD-NR decreased, and unilateral CFD-NR decreased on the affected side. In addition, NOSE and VAS scores tracked with unilateral CFD-NR on the affected side. CONCLUSION These preliminary results suggest a possible correlation between unilateral NR and patient-reported symptoms and imply that analysis of unilateral obstruction should focus on the affected side. A formal investigation of unilateral CFD-NR and patient-reported symptoms in a series of NAO patients is needed to determine if these variables are correlated.

Musculoskeletal Disorders in Referrals for Suspected Lumbosacral Radiculopathy

Cannon DE, Dillingham TR, Miao H, Andary MT, Pezzin LE: Musculoskeletal disorders in referrals for suspected lumbosacral radiculopathy. Am J Phys Med Rehabil 2007;86:957–961. Objective:An electrodiagnostic evaluation is often requested for patients with suspected lumbosacral radiculopathy. Although musculoskeletal disorders can produce lower-limb symptoms, their prevalence in this referral population is unknown. The purpose of this study was to determine the prevalence of common lower-limb musculoskeletal disorders in patients referred for lower-limb electrodiagnosis and determine whether these findings predict study outcome. Design:Subjects undergoing an electrodiagnostic study for lower-limb symptoms and suspected lumbosacral radiculopathy constituted the sample. A standardized clinical and electrodiagnostic evaluation was performed for all patients. Results:There were 170 subjects included. The mean age was 52 (SD = 17), and 45% were males. The total prevalence of musculoskeletal disorders in the sample was 32%. The prevalence in those with a normal study was 55% as compared with 21% in those with lumbosacral radiculopathy (P < 0.0001). Conclusions:Musculoskeletal disorders are common in patients suspected of having lumbosacral radiculopathy. The high prevalence among both patients with normal studies and those with radiculopathy and other disorders limits the usefulness of this information in predicting study outcome. In particular, it is common for patients to have two or more problems and the presence of a musculoskeletal disorder should not preclude such testing.

Modeling Nasal Physiology Changes due to Septal Perforations

Objective To use computational fluid dynamics (CFD) technology to help providers understand (1) how septal perforations may alter nasal physiology and (2) how these alterations are influenced by perforation size and location. Study Design Computer simulation study. Setting Facial plastic and reconstructive surgery clinic. Subjects and Methods With the aid of medical imaging and modeling software, septal perforations of 1 and 2 cm in anterior, posterior, and superior locations were virtually created in a nasal cavity digital model. The CFD techniques were used to analyze airflow, nasal resistance, air conditioning, and wall shear stress. Results Bilateral nasal resistance was not significantly altered by a septal perforation. Airflow allocation changed, with more air flowing through the lower-resistance nasal cavity. This effect was greater for anterior and posterior perforations than for the superior location. At the perforation sites, there was less localized heat and moisture flux and wall shear stress in superior perforations compared with those in anterior or posterior locations. For anterior perforations, a larger size produced higher wall shear and velocity, whereas in posterior perforations, a smaller size produced higher wall shear and velocity. Conclusion Septal perforations may alter nasal physiology. In the subject studied, airflow allocation to each side was changed as air was shunted through the perforation to the lower-resistance nasal cavity. Anterior and posterior perforations caused larger effects than those in a superior location. Increasing the size of anterior perforations and decreasing the size of posterior perforations enhanced alterations in wall shear and velocity at the perforation.

Evidence-Based Practice: Functional Rhinoplasty

The cause of nasal obstruction can often be attributed to pathologic conditions of the nasal valve. The key physical examination finding in nasal valve compromise is inspiratory collapse of the nasal sidewall. Validated subjective and objective measures evaluating nasal obstruction exist, although with weak correlation. Functional rhinoplasty encompasses the surgical techniques used to address obstruction occurring in this area. These techniques aim to increase the size of the nasal valve opening and/or strengthen the lateral nasal wall and nasal ala, preventing dynamic collapse. Much of the supporting evidence for functional rhinoplasty consists of observational studies that are universally favorable.

Deviated nasal septum hinders intranasal sprays: a computer simulation study.

BACKGROUND This study investigates how deviated nasal septum affects the quantity and distribution of spray particles, and examines the effects of inspiratory airflow and head position on particle transport. METHODS Deposition of spray particles was analysed using a three-dimensional computational fluid dynamics model created from a computed tomography scan of a human nose with leftward septal deviation and a right inferior turbinate hypertrophy. Five simulations were conducted using FluentTM software, with particle sizes ranging from 20-110 μm, a spray speed of 3 m/s, plume angle of 68(deg), and with steady state inspiratory airflow either present (15.7 L/min) or absent at varying head positions. RESULTS With inspiratory airflow present, posterior deposition on the obstructed side was approximately four times less than the contralateral side, regardless of head position, and was statistically significant. When airflow was absent, predicted deposition beyond the nasal valve on the left and right sides were between 16% and 69% lower and positively influenced by a dependent head position. CONCLUSION Simulations predicted that septal deviation significantly diminished drug delivery on the obstructed side. Furthermore, increased particle penetration was associated with presence of nasal airflow. Head position is an important factor in particle deposition patterns when inspiratory airflow is absent.

Computed intranasal spray penetration: comparisons before and after nasal surgery.

Quantitative methods for comparing intranasal drug delivery efficiencies pre‐ and postoperatively have not been fully utilized. The objective of this study is to use computational fluid dynamics techniques to evaluate aqueous nasal spray penetration efficiencies before and after surgical correction of intranasal anatomic deformities.

Use of Coblation in Resection of Juvenile Nasopharyngeal Angiofibroma

We present a series of 4 patients with juvenile nasopharyngeal angiofibroma (JNA) who underwent Coblation-assisted endoscopic resection after preoperative embolization, and discuss the use and advantages of endoscopic Coblation-assisted resection of JNA. Our limited case series suggests that Coblation may be used in the resection of JNA after embolization in a relatively safe, efficient, and effective manner. Coblation allows for decreased bleeding, less need for instrumentation, and improved visualization. There are limited published data in the literature to date on the use of Coblation in endoscopic JNA resection. We describe its use in a more extensive tumor than those previously reported. Further studies are needed to fully define the safety and utility of Coblation technology for this application.

Heterotopic salivary tissue

Salivary tissue can be present in the head and neck outside the usual locations of the major and minor salivary glands. This can be in the form of accessory salivary glands, in association with branchial cleft anomalies, or, less commonly, as heterotopic salivary gland tissue (HSGT). Heterotopic salivary gland tissue is defined as salivary tissue outside of the expected locations of major, minor, and accessory salivary glands with absence of clinical or histologic features of branchial cleft anomalies. Here we present the case of a 13-year-old girl who presented with a draining sinus of the lower neck, which was excised and, on histologic analysis, was consistent with HSGT. We include photographs and histologic images. A review of the literature on heterotopic salivary tissue in the neck is then presented including discussion of the presentation, clinical features, important considerations, and recommendations for management.

Two late complications of craniofacial trauma: case report and review of the literature

Injuries after blunt and penetrating trauma to the face are a common occurrence and are managed by specialists from several disciplines. After short-term care and immediate recovery, long-term complications can develop including cosmetic deformity, unsightly scarring, problems with soft tissue healing, malunion or nonunion of bony segments, diplopia or other visual complaints, malocclusion, hardware failure, and mucocele formation. Here, we present a report of 2 late complications recognized and treated in a patient 40 years after an episode of craniofacial trauma: epistaxis with symptomatic nasal congestion from fixation wires and mucocele formation. Management of this patient accompanied by endoscopic photographs and computed tomographic images is presented, and discussion of these complications along with review of the literature is provided.