Prognosis-Guided Reconstruction of Scalp and Skull Defects in Neurosurgical Patients.

BACKGROUND: This study aimed to formulate reconstructive recommendations for neurosurgical patients presenting with scalp and/or skull defects based on outcomes in a large series of patients. METHODS: An institutional review board-approved retrospective review of patients who underwent scalp and/or calvarial reconstruction was conducted. Complications were divided into minor and major; early, intermediate, and late. Univariate logistic regression models were conducted to identify independent predictors of complications. Mann-Whitney U tests were used to compare survival time. Kaplan-Meier curves were developed to compare exposure of titanium and bone cranioplasties. RESULTS: One hundred seventy-one patients who underwent 418 procedures were included (median 1 [1-3] surgeries per patient). Average age was 55 ± 15 years; 53% of patients were male. Median follow-up was 25.5 months [13.9-55.6 months], and 57 patients (33%) were deceased. Complications occurred following 48% of procedures; most common were titanium hardware exposure (36%), nonhealing wounds (23%), and infection (9%). Titanium cranioplasties became exposed 0.47 months [0.3-4.0 months] postoperatively. Frontal defect location was an independent predictor of major complications (odds ratio, 1.59; 95% confidence interval, 1.06-2.39; P = 0.026). Mortality rate for malignant intracranial neoplasms was 68.4% (median survival, 4.3 months), 39.1% for malignancies of both scalp and skull (7.0 months), 37.5% for scalp cancers (16.0 months), and 16.7% for meningiomas (28.2 months). CONCLUSIONS: Neurosurgical patients requiring scalp and/or skull reconstruction are a complex population undergoing multiple procedures with high complication rates. Given high exposure rate of titanium hardware shortly after reconstruction, titanium cranioplasty is recommended for patients with a prognosis less than 2 to 8 months.

Natural History of Metacarpal Subsidence following Trapeziectomy and Its Relationship to Clinical Outcomes.

METHODS: An institutional review board-approved retrospective review of patients who underwent trapeziectomy and ligament reconstruction and tendon interposition (LRTI) was conducted. Patient demographics, visual analogue scale pain scores, grip strength, pinch strengths, and radial and palmar abduction were collected. The trapezial space ratio (TSR) was measured by the scaphometacarpal distance divided by the length of the capitate. Subsidence [(postoperative TSR - preoperative TSR)/preoperative TSR] was measured and classified as severe (≥70%) or mild to moderate (<70%). Median rate of subsidence increase was calculated. Conolly-Rath scores were used to evaluate the proportion of good outcomes in each group. RESULTS: A total of 141 trapeziectomies with LRTI were included. Subsidence increased 6.7% (5.4% to 23.0%) per week before 16 weeks and 0.3% (0.1% to 0.8%) per week thereafter. Visual analogue scale pain scores were not significantly different between patients with severe or mild to moderate subsidence ( P = 0.25) 16 weeks after thumb mobilization. The proportion of good outcomes was comparable between the two groups ( P = 0.12). There was no correlation between subsidence and pain (ρ = -0.20; P = 0.24), grip (ρ = -0.02; P = 0.93), key (ρ = -0.13; P = 0.62), tripod (ρ = 0.16; P = 0.71), or index tip pinch strengths (ρ = -0.28; P = 0.43) or radial (ρ = -0.03; P = 0.92) or palmar (ρ = -0.15; P = 0.61) abduction. CONCLUSIONS: Subsidence occurs in all patients after trapeziectomy and LRTI, stabilizing 16 weeks after mobilization. Degree of subsidence does not correlate with postoperative outcomes. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, II.

Regional Peak Mucosal Cooling Predicts Radiofrequency Treatment Outcomes of Nasal Valve Obstruction.

OBJECTIVES/HYPOTHESIS: Low energy radiofrequency may offer effective treatment for narrow or obstructed nasal valve, yet its precise mechanism is not fully understood. STUDY DESIGN: Prospective, nonrandomized, case series. METHODS: Twenty prospective patients with internal nasal valve obstruction underwent office-based Vivaer treatment (Aerin Medical, Inc) under local anesthesia. Computational fluid dynamics (CFD) models were constructed based on the pre- and 90 days post-procedure computed tomography (CT) scans to identify salient changes in nasal airflow parameters. RESULTS: Patients' Nasal Obstruction Symptom Evaluation score (NOSE: pre-treatment 78.89 ± 11.57; post-treatment 31.39 ± 18.30, P = 5e-7) and Visual Analog Scale of nasal obstruction (VAS: pre-treatment 6.01 ± 1.83; post-treatment 3.44 ± 2.11, P = 1e-4) improved significantly at 90 days after the minimally invasive approach. Nasal airway volume in the treatment area increased ~7% 90 days post-treatment (pre-treatment 5.97 ± 1.20, post-treatment 6.38 ± 1.50 cm3 , P = .018), yet there were no statistically significant changes in the measured peak nasal inspiratory flowrate (PNIF, pre-treatment: 60.16 ± 34.49; post-treatment: 72.38 ± 43.66 ml/s; P = .13) and CFD computed nasal resistance (pre-treatment: 0.096 ± 0.065; post-treatment: 0.075 ± 0.026 Pa/(ml/s); P = .063). As validation, PNIF correlated significantly with nasal resistance (r = 0.47, P = .004). Among all the variables, only the peak mucosal cooling posterior to the nasal vestibule significantly correlated with the NOSE at baseline (r = -0.531, P = .023) and with post-treatment improvement (r = 0.659, P = .003). CONCLUSION: Minimal remodeling of the nasal valve (7% in this study) may have a profound effect on perceived nasal obstruction, despite little effect on nasal resistance, or PNIF. The results corroborated our previous findings that subjective relief of nasal obstruction correlates with regional mucosal cooling rather than nasal resistance or peak flow rate, a potential target for future effective, personalized therapeutic approaches. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:E1760-E1769, 2021.

Computational fluid dynamic analysis of aggressive turbinate reductions: is it a culprit of empty nose syndrome?

BACKGROUND: Empty nose syndrome (ENS) remains highly controversial, with aggressive inferior turbinate reduction (ITR) or mucociliary dysfunction frequently implicated. However, the appropriate degree of ITR is highly debatable. METHODS: We applied individual computed tomography (CT)-based computational fluid dynamics (CFD) to 5 patients receiving relatively aggressive ITR but with no ENS symptoms, and compared them to 27 symptomatic ENS patients who all had histories of aggressive ITRs, and 42 healthy controls. Patients' surgical outcomes were confirmed with 22-item Sino-Nasal Outcome Test (SNOT-22) (ITR: 6.40 ± 4.56; ENS: 58.2 ± 15.9; healthy: 13.2 ± 14.9), Nasal Obstruction Symptom Evaluation (NOSE) scores (ITR: 4.00 ± 2.24; ENS: 69.4 ± 17.1; healthy: 11.9 ± 12.9), and Empty Nose Syndrome 6-Item Questionnaire (ENS6Q) (≥11 for ENS). RESULTS: Both aggressive ITR without ENS symptoms and symptomatic ENS patients had significantly lower nasal resistance (ITR: 0.059 ± 0.020 Pa·s/mL; ENS: 0.052 ± 0.015 Pa·s/mL; healthy: 0.070 ± 0.021 Pa·s/mL) and higher cross-sectional areas surrounding the inferior turbinate (ITR: 0.94 ± 0.21 cm2 ; ENS: 1.19 ± 1.05 cm2 ; healthy: 0.42 ± 0.22 cm2 ) than healthy controls. The lack of significant differences among patient groups indicated similar degrees of surgeries between ITR with and without ENS symptom cohorts. However, symptomatic ENS patients have paradoxical significantly less airflow in the inferior meatus (ITR: 47.7% ± 23.6%; ENS: 25.8% ± 17.6%; healthy: 36.5 ± 15.9%; both p < 0.01), but higher airflow around the middle meatus (ITR: 49.7% ± 22.6%; ENS: 66.5% ± 18.3%; healthy: 49.9% ± 15.1%, p < 0.0001) than aggressive ITR without symptoms and controls. Aggressive ITR patients have increased inferior meatus airflow as expected (p < 0.05). This imbalanced airflow produced less inferior wall-shear-stress distribution among symptomatic ENS patients only (ITR: 42.45% ± 11.4%; ENS: 32.2% ± 12.6%; healthy: 49.7% ± 9.9%). ENS patients (n = 12) also had impaired nasal trigeminal function, as measured by menthol lateralization detection thresholds (ITR: 15.2 ± 1.2; ENS: 10.3 ± 3.9; healthy: 13.8 ± 3.09, both p < 0.0001). Surprisingly, aggressive ITR patients without ENS symptoms have better menthol lateralization detection thresholds (LDTs) than healthy controls. CONCLUSION: Although turbinate tissue loss is linked with ENS, the degree of ITR that might distinguish postoperative patient satisfaction in their nasal breathing vs development of ENS symptoms is unclear. Our results suggest that a combination of distorted nasal aerodynamics and loss of mucosal sensory function may potentially lead to ENS symptomology.

Asymptomatic vs symptomatic septal perforations: a computational fluid dynamics examination.

BACKGROUND: A nasal septal perforation (NSP) can lead to frustrating symptoms for some patients while remaining completely asymptomatic for others, without a clear mechanism differentiating them. METHODS: We applied individual computed tomography (CT)-based computational fluid dynamics (CFD) to examine the nasal aerodynamics differences between 5 asymptomatic and 15 symptomatic NSP patients. Patients' symptoms were confirmed through interviews, 22-item Sino-Nasal Outcome Test score (asymptomatic, 25 ± 18.8; symptomatic, 53.7 ± 18.2), nasal obstruction symptom evaluation score (asymptomatic, 28.0 ± 32.1; symptomatic, 62.2 ± 32.2), and review of medical history. RESULTS: No statistical differences were found in perforation location, size (asymptomatic, 1.94 ± 1.88 cm2 ; symptomatic, 1.36 ± 1.44 cm2 ), nasal resistance (asymptomatic, 0.059 ± 0.012 Pa·s/mL; symptomatic, 0.063 ± 0.022 Pa·s/mL), and computed flow rate shunting across the perforation (asymptomatic, 52.9 ± 30.9 mL/s; symptomatic, 27.4 ± 23.6 mL/s; p > 0.05). However, symptomatic patients had significantly higher wall shear stress (WSS) and heat flux, especially along the posterior perforation margin (WSS, 0.54 ± 0.12 vs 1.15 ± 0.49 Pa, p < 0.001; heat flux, 0.21 ± 0.05 vs 0.37 ± 0.14 W/cm2 , p < 0.01). A WSS cutoff at 0.72 Pa can separate asymptomatic vs symptomatic NSP with 87% sensitivity and 100% specificity. Flow visualization showed flow peaks toward the posterior margin that may be responsible for the high WSS and heat flux among symptomatic NSPs. CONCLUSION: This study is the first CFD examination of asymptomatic and symptomatic NSP with regional aerodynamics and stress abnormalities, beyond size or location, being implicated as the mechanism behind the symptomology of NSP. This finding could serve as an objective basis for future personalized treatment decisions and optimization.

Computational fluid dynamics after endoscopic endonasal skull base surgery-possible empty nose syndrome in the context of middle turbinate resection.

BACKGROUND: Empty nose syndrome (ENS) is a rare and debilitating disease with a controversial definition, etiology, and treatment. One puzzling fact is that patients who undergo an endoscopic endonasal approach (EEA) often have resection of multiple anatomic structures, yet seldom develop ENS. In this pilot study, we analyzed and compared the computational fluid dynamics (CFD) and symptoms among post-EEA patients, ENS patients, and healthy subjects. METHODS: Computed tomography scans of 4 post-EEA patients were collected and analyzed using CFD techniques. Two patients had significant ENS symptoms based on results of the Empty Nose Syndrome 6-item Questionnaire (score >11), whereas the other 2 were asymptomatic. As a reference, their results were compared with previously published CFD results of 27 non-EEA ENS patients and 42 healthy controls. RESULTS: Post-EEA patients with ENS symptoms had a similar nasal airflow pattern as non-EEA ENS patients. This pattern differed significantly from that of EEA patients without ENS symptoms and healthy controls. Overall, groups with ENS symptoms exhibited airflow dominant in the middle meatus region and a significantly lower percentage of airflow in the inferior turbinate region (EEA with ENS, 17.74 ± 4.00% vs EEA without ENS, 51.25 ± 3.33% [t test, p < 0.02]; non-EEA ENS, 25.8 ± 17.6%; healthy subjects, 36.5 ± 15.9%) as well as lower peak wall shear stress (EEA with ENS, 0.30 ± 0.13 Pa vs EEA without ENS, 0.61 ± 0.03 Pa [p = 0.003]; non-EEA ENS, 0.58 ± 0.24 Pa; healthy subjects, 1.18 ± 0.81 Pa). CONCLUSION: These results suggest that turbinectomy and/or posterior septectomy may have a varying functional impact and that ENS symptoms go beyond anatomy and correlate with aerodynamic changes. The findings open the door for CFD as a potential objective diagnosis tool for ENS.

Reconstruction of Secondary Calvarial Defects with Ex Situ Split Calvarial Bone Grafts: Long-Term Evaluation of Outcomes.

BACKGROUND: Autologous bone continues to represent the first choice for reconstruction of calvarial defects. However, unanswered questions remain on the natural history of the graft and the influence of patient-related risk factors. This study investigated the outcomes of skull reconstruction with split calvarial bone graft, examining the natural history and stratifying the risk of unfavorable results. METHODS: Patients who underwent cranioplasty with split calvarial bone graft between 1982 and 2016 at the Cleveland Clinic were analyzed, recording demographics, comorbidities, indications, size and location of defect, and outcomes including complications and reoperations. Changes in graft thickness were analyzed using computed tomographic and magnetic resonance imaging scans. RESULTS: Forty-one patients with an average age of 33.2 years, cranial defect size of 68 cm, and mean follow-up of 28 months were included. The majority of patients (85 percent) had significant risk factors, with 43 percent suffering prior infection. Seventy-three percent of patients experienced successful restoration. A major complication was recorded in 26.8 percent; resorption occurred in 19.5 percent of patients (in 75 percent only at the recipient site), with 9.8 percent requiring reoperation. Patients with one or more risk factors or a smoking history were more likely to experience a complication. The mean ratio of the graft to the bicortical donor bone thickness was 0.48 ± 0.17 for the recipient site and 0.57 ± 0.10 for the donor site at an average radiographic follow-up of 11.9 ± 10.9 years. CONCLUSIONS: This study demonstrated a 73.2 percent first-attempt success rate in a high-risk population. The grafts maintain thickness over time, with no evidence of bone hypertrophy. Defect characteristics and patient systemic factors appear to be important variables influencing success. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Modeling congenital nasal pyriform aperture stenosis using computational fluid dynamics.

OBJECTIVES: Congenital nasal pyriform aperture stenosis (CNPAS) is a rare cause of airway obstruction in the neonate. Computational airway modeling has not been done in neonates and young infants to understand the impact of stenosis on functional nasal airflow. In this study, we 1) applied computational fluid dynamics (CFD) model to the airway of a neonate with CNPAS and 2) compare airflow dynamics of a normal and CNPAS airway. METHODS: Three-dimensional models of the nasal airway of a normal neonate and a neonate with CNPAS were created using computed tomography scans of the facial bones. Measured anatomic parameters included volume, surface area, and cross-sectional area. CFD simulation was then performed. Simulated flow parameters included pressure, average velocity, and resistance. RESULTS: The neonate with CNPAS had a lesser volume (2.74 cm3 vs. 4.50 cm3) and surface area (18.8 cm2 vs. 45.5 cm2) than the normal airway. The CNPAS airway had a lesser bilateral cross-sectional area and average cross-sectional velocity throughout the length of the model. While there is a large pressure drop in the normal airway immediately after the entry point, the pressure drop in the CNPAS airway occurs more posteriorly. The total nasal resistance was approximately eight-fold greater in the CNPAS airway than the normal. CONCLUSIONS: CFD analysis can be performed on airways of neonates with nasal obstruction, such as in CNPAS. A CFD model may help characterize severity of airway obstruction as it can predict the three-dimensional pattern of airflow. Determining the role of CFD in clinical management of CNPAS requires further investigation.

Computational fluid dynamics evaluation of posterior septectomy as a viable treatment option for large septal perforations.

BACKGROUND: Numerous surgical techniques exist to treat nasal septal perforation (NSP). The surgical closure of large NSPs (>2 cm) is still challenging. Posterior septectomy has been reported as a simple alternative to treat large NSP, yet its mechanisms for symptom relief are not clear, and if failed, its consequence cannot be easily reversed. METHODS: Ten NSP patients were recruited: 5 underwent posterior septectomy and 5 underwent conventional flap or button repair. Computational fluid dynamics (CFD) simulated the nasal aerodynamics based on computed tomography (CT) scans. All patients had preoperative CT; however, only 4 had postoperative CT: 2 underwent posterior septectomy and the other 2 underwent flap repair. We examined surgical outcomes and the nasal airflow features among the 2 treatment options. RESULTS: Both groups of patients had good outcomes based on chart review. Patients undergoing septectomy had significantly larger perforation size (2.32 ± 0.87 vs 1.21 ± 0.60 cm), higher flow rate across the perforation (47.8 ± 28.6 vs 18.3 ± 12.2 mL/second), and higher wall shear stress (WSS) along the posterior perforation margin (1.39 ± 0.52 vs 1.15 ± 0.58 Pa). The posterior WSS significantly correlated with crossover flow velocity (r = 0.77, p = 0.009) and was reduced by almost 67% postseptectomy, and by 29% postrepair. CONCLUSION: This is the first CFD analysis on an NSP patient cohort. NSP resulted in flow disturbance and increased WSS that potentially led to symptomatology. The removal of high stress points along the posterior margin may explain why posterior septectomy can be an effective treatment option. Aerodynamic abnormalities, in addition to perforation size and location, could serve as basis for future treatment decisions.