Surgical Risk after Unilateral Lobectomy Versus Total Thyroidectomy: A Review of 47,434 Patients

Review Article

Austin J Otolaryngol. 2014;1(3): 8.

Surgical Risk after Unilateral Lobectomy Versus Total Thyroidectomy: A Review of 47,434 Patients

Charles Du Qin1, Sujata Saha1, Ryan Meacham2, Sandeep Samant2, Jon P Ver Halen3* and John YS Kim1

1Division of Plastic and Reconstructive Surgery, Northwestern University, USA

2Department of Otolaryngology- Head and Neck Surgery, University of Tennessee Health Science Center, USA

3Division of Plastic and Reconstructive Surgery, Baptist Cancer Center, USA

*Corresponding author: Jon P Ver Halen, Division of Plastic and Reconstructive Surgery, Baptist Cancer Center, Department of Surgery, St. Jude Children’s Research Hospital, Department of Surgical Oncology, Vanderbilt-Ingram Cancer Center, 3268 Duke Circle, Germantown, TN 38139, USA

Received: September 12, 2014; Accepted: October 25, 2014; Published: October 30, 2014


Background: We reviewed the 2005-2012 ACS-NSQIP databases to evaluate factors associated with adverse events (AE) after unilateral thyroid lobectomy (UL) and total thyroidectomy (TT).

Methods: All unilateral lobectomies and total thyroidectomies performed from 2005 to 2012 were identified for analysis. The cohort was characterized with respect to preoperative and demographic characteristics, complications, reoperation, and mortality.

Results: 47,434 patients were identified, of which 17,584 underwent unilateral lobectomy and 29,850 underwent total thyroidectomy. On multivariable regression analysis, UL was associated with a 2.786 greater risk of returning to the OR, and a 1.377 risk of surgical complications. The increased risk of return to the OR was eliminated when controlling for patients returning to the OR for completion thyroidectomy after UL.

Conclusion: NSQIP is the only dataset that is able to discern between unilateral lobectomy and total thyroidectomy to make viable comparisons in outcomes. The NSQIP dataset may be imperfect, as pertinent details of chemotherapy and radiation, and procedure-specific complications, including recurrent laryngeal nerve palsy and hypocalcemia, are not tracked. In spite of this, our findings suggest avenues for improvement in the care of thyroidectomy patients, and suggest directions for a thyroidectomy-specific outcomes database.

Keywords: Thyroidectomy; NSQIP; Lobectomy; Outcomes; Mortality; Complications


The incidence and severity of thyroid cancer continues to rise. The rate for new diagnoses of thyroid cancer has increased an average of 6.4% per year over the last 10 years and mortality of thyroid cancer has increased 0.9% per year over the same period [1]. With this increasing disease burden, the need for both diagnostic and therapeutic thyroidectomy remains high.

Although thyroid surgery is a relatively safe procedure, there are a number of severe, preventable complications [2,3]. Because medical sustainability proposals link reimbursements with quality control measures, it is imperative to establish normative data by which surgeons and hospitals can be compared to their cohorts with regard to thyroidectomy outcomes. Although more than 20,000 thyroidectomies are performed every year in the United States, only a few papers have attempted to describe high-volume, multi-center outcome data for thyroid surgery [4,5].

Many factors may be weighed when considering a unilateral thyroid lobectomy (UL) versus total thyroidectomy (TT). Even in the setting of known thyroid cancer, there is not always agreement about the requirement for lobectomy or total thyroidectomy [6,7]. Furthermore, there remains discussion about the need for central and lateral neck dissection in the setting of thyroid cancer [8,9]. It would stand to reason that with an increasing extent of thyroid surgery there would be a commensurate increase in nontechnical complications (i.e., not including recurrent laryngeal nerve injury and hypoparathyroidism), but the details of this relationship have not been described. Conversely, the technically more complicated procedure of thyroid-conserving surgery could, in turn, increase technical complications.

The American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) is a multi-institutional collaborative effort that collects data from more than 500 hospitals. Over 230 variables are captured including preoperative status, intraoperative variables, and postoperative outcomes, including 30- day postoperative adverse events (AE). The NSQIP database is an excellent resource for population-based analyses of critical health care issues, including registry-based trials, risk adjustment, surgical outcomes and cost [10].

The purpose of this study was to use the ACS-NSQIP database to evaluate a large volume of patients to assess the relationship between the type of thyroid surgery and surgical outcomes. Although most reports on thyroidectomy outcomes focus on technical complications such as recurrent laryngeal nerve injury and hypoparathyroidism, we examined all outcomes comparing UL to TT.


Data acquisition and patient population

Data collection methods for the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) registry have been previously described [11,12]. All study aspects were approved by the respective Institutional Review Boards.

The 2005 to 2012 NSQIP registries were queried for all patients who were recorded to have undergone a total thyroidectomy or a unilateral lobectomy. Total thyroidectomy cases were identified by the presence of the Current Procedural Terminology (CPT) codes 60240 and 60225, and unilateral lobectomies were identified by the CPT code 60220. Patients were stratified by surgical modality.

Risk adjustment variables and outcomes

NSQIP-defined preoperative variables were compared between total thyroidectomy and unilateral lobectomy. They included demographic variables (eg, age, BMI class); lifestyle variables (eg, smoking), medical comorbidities (eg, diabetes, dyspnea, hypertension, COPD, congestive heart failure, bleeding disorders, prior angioplasty or cardiac surgery, previous stroke or transient ischemic attack, radiotherapy within 90 days of operation, chemotherapy within 30 days of operation, previous operations within 30 days of operation) and intraoperative characteristics (e.g., total operation time). Tracked 30-day adverse events (AE) were categorized as surgical complications, medical complications, and overall complications. Surgical complications included superficial, deep, organ-space surgical site infection (SSI), or wound disruption. Medical complications included deep venous thrombosis (DVT), pulmonary embolism (PE), unplanned re-intubation, ventilator dependence >48 hours, progressive renal insufficiency, acute renal failure, coma, stroke, cardiac arrest, myocardial infarction (MI), peripheral nerve injury, pneumonia, urinary tract infection (UTI), blood transfusions, and sepsis/septic shock. All AE were used as defined in the NSQIP user guide. Overall complications included all surgical and medical complications. Data for unplanned readmission, which was available in 2011 and 2012, was tracked. Readmission was defined as an unplanned readmission to the same or other hospital within 30 days of the primary or concurrent procedure. Return to the operating room within 30 days identified all major surgical procedures that required the patient to be taken to the surgical operating room for intervention of any kind.

Statistical analysis

Chi-square tests, for categorical variables, and Student t test, for continuous variables, were used to identify differences in perioperative variables between the two groups. Significance was defined as P < 0.05. This method was then used to identify differences in overall, medical, and surgical complications. Perioperative variables with n = 10 and P < 0.2 were identified as possible predictors for AE and included in a binary logistic regression which assessed the independent association of surgical modality with overall, medical, and surgical complications, return to the operating room, and unplanned readmission, with proper risk adjustment for other factors. Again, P < 0.05 was considered significant. Hosmer-Lemeshow (H-L) and c-statistics were calculated to assess model calibration and discriminatory capability, respectively. All analysis was performed using SPSS version 22 (IBM Corp, Armonk, NY).


Cohort characteristics

Between 2005 and 2012, 47,434 patients were identified for our analysis. 17,584 patients (37%) underwent UL and 29,850 patients (63%) underwent TT (Table 1). The UL group was more likely to be male and have a history of alcohol use. Comorbidities and clinical characteristics including diabetes, smoking, dyspnea, COPD, CHF, hypertension, and steroid use were more prevalent in the TT group. Patients who underwent TT were more likely to be ASA class 3, 4, or 5, older, and have a higher BMI.