Novel Thyroidectomy Difficulty Scale Correlates with Operative Times

Abstract

Introduction The aim of this study was to evaluate a new thyroidectomy difficulty scale (TDS) for its inter-rater agreement, correspondence with operative times, and correlation with complications. Methods We developed a four item, 20-point TDS. Following cases where two board-certified surgeons participated, each surgeon completed a TDS, blinded to the other’s responses. Paired sets of TDS scores were compared. The relationship between operative time and TDS scores was analyzed with linear regression. Multiple regression evaluated the association of TDS scores and other clinical data with operative times. Results A total of 119 patients were scored using TDS. In this cohort, 22.7% suffered from hyperthyroidism, 37.8% experienced compressive symptoms, and 58.8% had cancer. The median total TDS score was 8, and both surgeons’ total scores exhibited a high degree of correlation. 87.4% of both raters’ total scores were within one point of each other. Patients with hyperthyroidism received higher median scores compared to euthyroid patients (10 vs. 8, p<0.01). Similarly, patients who suffered a complication had higher scores compared to those patients without complications (10 vs. 8, p= 0.04). TDS scores demonstrated a linear relationship with operative times (R2 = 0.36, p<0.01, Figure 1). Cases with a score of 14 or greater took 41.0% longer compared to cases with scores of five or less (p<0.01). In multiple regression analysis, TDS scores independently predicted operative time (p<0.01). Conclusion The TDS is an accurate tool, and scores correlate with more difficult thyroidectomies as measured by complications and operative times.

Identifying Predictors of a Difficult Thyroidectomy

“…In our previous work, this scale was internally validated, and was shown to have high interrater agreement. Higher TDS scores were noted to correlate with both longer operative times and higher rates of complications (3).…”

“…In order to have a more objective measurement of difficulty, Schneider and colleagues developed a "Thyroidectomy Difficulty Scale" (TDS) (3). TDS is a four item (vascularity, friability, mobility/fibrosis, gland size), 20-point scale, in which each item is scored on a five-point scale.…”

“…The incidence of these complications increases with thyroid pathology associated with increased gland size, fibrosis, vascularity, or inflammation (4)(5)(6). Although certain disease states such as hyperthyroidism, goiter, and thyroiditis are associated with more difficult thyroidectomies, the degree of difficulty often varies widely, and it is difficult to quantify or predict the level of difficulty of these cases preoperatively (3,(5)(6)(7)(8)(9)(10)(11). Surgical risk in thyroidectomy is well studied, but there is no literature regarding the quantification of "difficulty" or an objective measure of "difficulty" for a thyroidectomy (4)(5)(6)(7)(8)(9)(12)(13)(14)(15).…”

Predicting difficulty of thyroidectomy preoperatively

“…18 The Thyroidectomy Difficulty Scale, developed by Schneider and colleagues incorporates all of these aspects of difficulty -vascularity, friability, mobility and gland size -to create a single composite score of difficulty. 1,2 Preoperative variables that predict a difficult thyroid surgery were identified using the Thyroidectomy Difficulty Scale. Hyperthyroidism (TSH <0.4 mIU/L), Hashimoto's thyroiditis (anti-thyroid peroxidase antibody is >30 IU/ml), and pre-operative anti-thyroglobulin antibody positivity (greater than 4 IU/ml) were associated with a more difficult thyroidectomy.…”

“…After thyroidectomy, the surgeons completed the TDS. 1,2 In present study, a modification of the above scale was used for convenience.…”