Neck incision planning for total laryngectomy: A finite element analysis

Force Metrics and Suspension Times for Microlaryngoscopy Procedures

OBJECTIVE

To determine the difference in force metrics measured by the laryngeal force sensor for various suspension microlaryngoscopy (SML) procedures and their perioperative narcotic requirements.

STUDY DESIGN

Prospective observational study.

SETTING

Academic tertiary center.

METHODS

The laryngeal force sensoris a force sensor designed for SML procedures. Prospectively enrolled patients had dynamic recordings of maximum force, average force, suspension time, and total impulse. Procedures were grouped into excision of striking zone lesions, nonstriking zone lesions, endoscopic cancer surgery with margin control, and airway dilation. Narcotic administration in the intraoperative period and postanesthesia care unit was also recorded and converted into IV morphine equivalents. Surgeons were blinded to the force recordings during surgery to prevent operator bias.

RESULTS

In total, 110 patients completed the study. There was no significant difference in average force across different procedures, however, a significant difference was seen for maximum force (P = 0.025), suspension time (P < 0.001), and total impulse (P = 0.002). The highest values were seen for endoscopic cancer surgeries with margin control with a mean maximum force of 49.4 lbf (95%CI, 37.1-61.7), mean suspension time of 60.2 minutes (95%CI, 40.5-79.9), and mean total impulse of 31.3 ton*s (95%CI, 15.2-47.3). A significant difference (P < 0.01) in perioperative narcotic requirements was also seen, with endoscopic cancer surgery cases having the highest requirements at 27.6 mg of ME (95%CI, 16.1-39.2 mg).

CONCLUSION

Significant differences in force metrics exist between various SML procedures. Endoscopic cancer surgery is associated with higher force metrics and perioperative narcotic requirements.

Increased prevalence of neural monitoring during thyroidectomy: Global surgical survey

OBJECTIVE

To investigate intraoperative nerve monitoring (IONM) use among thyroid surgeons.

METHODS

A 25-question survey was used to assess attitudes regarding IONM use. Surveys were sent to surgeons registered to the American Academy of Otolaryngology-Head and Neck Surgery, International Association of Endocrine Surgeons, and American Head and Neck Society.

RESULTS

Among 1,015 respondents, 83% reported using IONM (65.1% always using IONM and 18.1% reporting selective use). For selective users, a majority reported using IONM for reoperative cases (95.1%) and in cases with preoperative vocal cord paralysis (59.8%). When comparing location, there was a significant difference in IONM implementation (P < 0.001), with 70.4% of North American responders using it ubiquitously compared to 27.4% of non-North American responders. Preoperative laryngeal exam was performed more universally by North American surgeons and more selectively by non-North American surgeons (P < 0.001). Other attitudes toward their implementation and the postoperative laryngeal exam were similar. Surgeons ≤45 years of age and those with ≤15 years of practice used IONM more than their peers (P < 0.001). Thyroid surgery volume, fellowship training, and type of practice had no bearing on IONM use.

CONCLUSION

The prevalence of IONM in thyroid and parathyroid surgeries has increased significantly over the past decade, with 83% of surgeons using IONM in some or all cases. Although IONM use may be more ubiquitous in North America, attitudes toward its implementation and pre- and postoperative laryngeal exams are fairly uniform. IONM use is more prevalent among younger surgeons, whereas its use has no correlation with thyroid surgery volume or type of practice.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:1097-1104, 2020.

Biomechanical Modeling of Wounded Skin

Skin injury is the most common type of injury, which manifests itself in the form of wounds and cuts. A minor wound repairs itself within a short span of time. However, deep wounds require adequate care and sometime clinical interventions such as surgical suturing for their timely closure and healing. In literature, mechanical properties of skin and other tissues are well known. However, the anisotropic behavior of wounded skin has not been studied yet, specifically with respect to localized overstraining and possibilities of rupture. In the current work, the biomechanics of common skin wound geometries were studied with a biofidelic skin phantom, using uniaxial mechanical testing and Digital Image Correlation (DIC). Global and local mechanical properties were investigated, and possibilities of rupture due to localized overstraining were studied across different wound geometries and locations. Based on the experiments, a finite element (FE) model was developed for a common elliptical skin wound geometry. The fidelity of this FE model was evaluated with simulation of uniaxial tension tests. The induced strain distributions and stress-stretch responses of the FE model correlated very well with the experiments (R2 > 0.95). This model would be useful for prediction of the mechanical response of common wound geometries, especially with respect to their chances of rupture due to localized overstraining. This knowledge would be indispensable for pre-surgical planning, and also in robotic surgeries, for selection of appropriate wound closure techniques, which do not overstrain the skin tissue or initiate tearing.

Laryngeal Force Sensor: Quantifying Extralaryngeal Complications after Suspension Microlaryngoscopy

Objectives

To develop a novel sensor capable of dynamically analyzing the force exerted during suspension microlaryngoscopy and to examine the relationship between force and postoperative tongue complications.

Study Design

Prospective observational study.

Setting

Academic tertiary care center.

Methods

The laryngeal force sensor is a designed for use during microphonosurgery. Prospectively enrolled patients completed pre- and postoperative surveys to assess the development of tongue-related symptoms (dysgeusia, pain, paresthesia, and paresis) or dysphagia (10-item Eating Assessment Tool [EAT-10]). To prevent operator bias, surgeons were blinded to the force recordings during surgery.

Results

Fifty-six patients completed the study. Of these, 20 (36%) developed postoperative tongue symptoms, and 12 (21%) had abnormal EAT-10 scores. The mean maximum force across all procedures was 164.7 N (95% CI, 141.0-188.4; range, 48.5-402.6), while the mean suspension time was 34.3 minutes (95% CI, 27.4-41.2; range, 7.1-108.1). Multiple logistic regression showed maximum force (odds ratio, 1.15; 95% CI, 1.02-1.29; P = .019) and female sex (30.1%; 95% CI, 22.7%-37.5%; P < .001) as significant predictors for the development of tongue-related symptoms. The only significant predictor of an abnormal postoperative EAT-10 score was an increased maximum force (odds ratio, 1.03; 95% CI, 1.00-1.06; P = .045).

Conclusions

The laryngeal force sensor is capable of providing dynamic force measurements throughout suspension microlaryngoscopy. An increase in maximum force during surgery may be a significant predictor for the development of tongue-related symptoms and an abnormal EAT-10 score. Female patients may also be at greater risk for developing postoperative tongue symptoms.

Neck Incision Planning for Total Laryngectomy with Pharyngectomy

Objectives

To investigate the effect of skin incision location for total laryngectomy with pharyngectomy (TLP) on postoperative outcomes including wound dehiscence and infection rate.

Study Design

Case series with chart review.

Setting

Academic tertiary care center.

Methods

A retrospective analysis was conducted of all patients undergoing TLP with flap closure at Johns Hopkins Medical Institutes between August 2005 and February 2013. The effects of patient characteristics and skin incision technique on postoperative wound dehiscence and infection were analyzed using cross-tabulations and multivariate regression modeling.

Results

A total of 49 patients were included in the analysis; 31 received low-neck apron (LNA) incisions with an incorporated tracheostoma, while the remaining 18 had mid-neck apron (MNA) incisions with separate tracheostoma fashioned inferior to their incisions. Of these patients, 17 experienced incisional wound dehiscence (35%), and 18 contracted postoperative infections (37%). Generalized linear regression models demonstrated a significantly increased odds of wound dehiscence for patients with LNA incisions (odds ratio 29.8; 95% CI, 1.4-631.5, P = .029). There were no significant predictive variables for postoperative infection.

Conclusions

These results demonstrate that the use of a separately fashioned tracheostoma with MNA incision is associated with decreased rate of wound dehiscence in patients undergoing TLP.