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Digital implementations of control laws typically involve discretization with respect to both time and space, and a control law that can achieve a task at coarser levels of discretization can be said to require less control attention, and also reduced implementation costs. One means of quantitatively capturing the attention of a control law is to measure the rate of change of the control with respect to changes in state and time. In this paper we present an attention-minimizing control law for ball catching and other target tracking tasks based on Brockett's attention criterion. We first highlight the connections between this attention criterion and some well-known principles from human motor control. Under the assumption that the optimal control law is the sum of a linear time-varying feedback term and a time-varying feedforward term, we derive an LQR-based minimum attention tracking control law that is stable, and obtained efficiently via a finite-dimensional optimization over the symmetric positive-definite matrices. Taking ball catching as our primary task, we perform numerical experiments comparing the performance of the various control strategies examined in the paper. Consistent with prevailing theories about human ball catching, our results exhibit several familiar features, e.g., the transition from open-loop to closed-loop control during the catching movement, and improved robustness to spatiotemporal discretization. The presented control laws are applicable to more general tracking problems that are subject to limited communication resources.

Introduction: Transaxillary robotic thyroidectomy is considered a technically feasible and safe treatment option for patients with low-risk papillary thyroid carcinoma (PTC). The aim of the present study was to determine the factors that contribute to the perioperative surgical outcomes of robotic thyroidectomy and to suggest guidelines for patient selection to be used by surgeons inexperienced in the technique., Method: We reviewed the records of 275 patients with PTC who underwent robotic total thyroidectomy using a gasless, transaxillary single-incision approach at Yonsei University Health System, South Korea, between January 2011 and May 2012. The association between surgical outcomes and clinicopathologic factors was assessed using linear and logistic regression analysis., Results: The contributing factors for surgical outcomes of robotic thyroidectomy were categorized as patient factors, including gender and body mass index (BMI), and thyroid-specific factors, including thyroid gland size, coexistent thyroiditis, tumor size, and serum anti-thyroglobulin antibody and anti-microsomal antibody titers. Of these, male gender, a large thyroid gland, and thyroiditis significantly increased the total operation time. Male gender, thyroiditis, and overweight BMI increased the working space time, and a large thyroid gland and overweight BMI affected the console time. A large thyroid gland and histological thyroiditis were associated with increased intraoperative blood loss. There was no association between postoperative complications and clinicopathologic parameters., Conclusion: Male gender, overweight BMI, a large thyroid gland, and coexistent thyroiditis adversely affected the surgical outcome of robotic thyroidectomy. Surgeons inexperienced in the technique should avoid or carefully approach individuals with these factors.

Background: Body image is associated with self-esteem and identity and has a close relationship with quality of life (QoL). We compared the impact of surgical scars on the patient's perception of body image between conventional open thyroidectomy (OT) and robotic thyroidectomy (RT) in female papillary thyroid carcinoma patients., Methods: From October 2009 to December 2010, we enrolled prospectively 116 papillary thyroid carcinoma patients who underwent total thyroidectomy at the Yonsei University Health System (Seoul, Korea). Of these 116 patients, 56 had OT and 60 RT. Their scars were assessed using the Vancouver Scar Scale (VSS), and psychometric properties were evaluated using the Body Image Scale (BIS) questionnaire postoperatively. Both groups were compared using cross-sectional and time-series methods., Results: Mean age was significantly younger in the RT group. Regarding scar quality, the OT group showed superiority in scar pigmentation and the total VSS score during the early postoperative period, but the VSS score improved over time and was similar between both groups at 9 months. The RT group had better scores regarding most of the BIS items, a trend that remained relatively constant over time. In patients with noticeable scars (VSS ≥ 2) at 9 months, the RT group had better BIS scores regarding almost all items, including "self-conscious," "physical attractiveness," "feeling of less feminine," "sexual attractiveness," "dissatisfaction with body, scar and appearance when dressed," and "avoidance of people due to appearance.", Conclusion: RT provides a better self-body image and improves QoL compared with conventional OT by avoiding a noticeable cervical scar., (Copyright © 2014 Mosby, Inc. All rights reserved.)

Background: Using the da Vinci(®) robotic system, surgeons can complete secure thyroidectomy without noticeable neck scarring. This study compared the surgical completeness of transaxillary robotic thyroidectomy (RT) with conventional open procedures (OT) in treating papillary thyroid carcinoma (PTC) patients., Materials and Methods: From April 2009 through February 2011, 94 PTC patients underwent total thyroidectomy with central compartment neck dissection (CCND) at Yonsei University College of Medicine. All patients received 1.1 GBq radioactive iodine (RAI) ablation, post-therapy whole-body scans (TxWBS), and diagnostic WBS (DxWBS) 1 year later. We prospectively compared patient clinicopathologic characteristics and surgical completeness between the two groups., Results: Fifty-one patients underwent OT and 43 underwent RT. Mean age was significantly younger in the RT group. Tumor size, capsular-invasion frequency, multifocality, bilaterality, and central nodal metastasis were not different between the two groups. The number of retrieved nodes during CCND did not significantly differ between the groups. There was no significant difference between the OT and RT groups in stimulated thyroglobulin levels acquired during TxWBS and DxWBS. The RAI uptake ratios at TxWBS were significantly higher in the RT group compared with the OT group; however, follow-up DxWBS showed no difference in RAI uptake ratios. Also, the ablation success rate was similar between the two groups. There were no abnormal findings in follow-up neck ultrasonography in either group., Conclusion: Remnant thyroid tissue ablation after transaxillary RT was successfully managed by 1.1 GBq RAI. RT showed similar surgical completeness versus conventional OT, and provides a safe and feasible surgical option for PTC patients.

Background: Robotic applications have achieved safe and precise thyroidectomy with notable cosmetic and functional benefits. This study was designed to document the influence of body habitus on robotic thyroidectomy in papillary thyroid carcinoma (PTC) patients., Methods: From July 2009 to February 2010, 352 patients underwent robotic thyroidectomy using a gasless, transaxillary single-incision approach at Yonsei University Health System. Body habitus was described using body mass index category (normal weight, overweight, obese), neck length, shoulder width, and shoulder width to neck length ratios. The impact of body habitus on surgical outcomes was analyzed with respect to operation time, number of retrieved central nodes, bleeding amount, and postoperative complications., Results: Of the 352 patients, 217 underwent less than total thyroidectomy and 135 underwent total thyroidectomy. Operative variables (i.e. operation times, bleeding amounts, and numbers of retrieved central nodes) showed no significant differences between three BMI groups for less than total thyroidectomy. However, total operation and working space times were longer for obese patients during total thyroidectomy. In particular, shoulder width was positively correlated with total operation time, working space time, console time, and number of retrieved central nodes. On the other hand, postoperative complications were not significantly different in the three BMI groups and showed no significant correlation with the other indices of body habitus., Conclusions: Standardized robotic thyroidectomy can be performed safely and feasibly in patients with a large body habitus despite longer operation times.

Background: Robotic operations have enabled a safer and more meticulous approach to thyroidectomy with the notable benefit of improved cosmesis and decreases in postoperative pain and swallowing discomfort. The aim of this study was to document the early surgical outcomes of robotic thyroidectomy in patients with papillary thyroid carcinoma (PTC) by comparing it with conventional open thyroidectomy., Methods: From October 2007 to September 2008, 458 patients with PTC underwent thyroidectomy at the Yonsei University Health System. Of these patients, 266 patients were in the conventional open group and 192 patients were in the robotic group. These 2 groups were compared retrospectively with respect to clinicopathologic characteristics and surgical outcomes., Results: The mean follow-up period was 29.1 months. Mean tumor size, incidence of capsular invasion, multiplicity, and central nodal metastasis showed no significant difference between the 2 groups. Total thyroidectomy was performed more frequently in the open group. In terms of operation times, the robotic group had a significantly greater length of time for total thyroidectomy and subtotal thyroidectomy. The total number of retrieved central lymph nodes was greater in the open group (5.7 vs 4.6, P = .004). The 2 groups showed no differences in intraoperative and postoperative complications. The postoperative serum thyroglobulin levels were similar in both groups (0.25 vs 0.22 ng/mL, P = .648) and 2-year follow-up sonography of 433 patients revealed no recurrences. No abnormal I(131) uptake was observed in whole-body scans in either group., Conclusion: Robotic thyroidectomy was similar to conventional open thyroidectomy in terms of early surgical outcomes but offers advantages. We conclude that robotic thyroidectomy offers a safe, feasible alternative to conventional open thyroidectomy in patients with PTC., (Copyright © 2012 Mosby, Inc. All rights reserved.)

Objective: To confirm the merits of robotic thyroid surgery by comparing the surgical outcomes of robotic-assisted and conventional endoscopic thyroidectomy in papillary thyroid microcarcinoma (PTMC) patients., Background: Robot-assisted surgical techniques are widely utilized, and substantially, overcome the limitations of conventional endoscopic surgery. Furthermore, recently, robotic procedures were introduced to the thyroidectomy field., Methods: From November 2001 to July 2009, 1150 patients with PTMC underwent endoscopic thyroidectomy using a gasless, trans-axillary approach. Of these patients, 580 underwent a robotic procedure (the robotic group; RG) and 570 a conventional endoscopic procedure (the conventional endoscopic group; EG). These 2 groups were retrospectively compared in terms of their clinicopathologic characteristics, early surgical outcomes, and surgical completeness., Results: Total thyroidectomy was performed more frequently in the RG. Although mean operation times were not statistically different, the mean number of central nodes retrieved was greater in the RG than in the EG. Mean tumor size were not significantly different in the 2 groups, but the RG showed more frequent central node metastasis and capsular invasion. Tumor and nodal statuses in the RG were more advanced than in the EG. Regarding postoperative complications, transient hypocalcemia was more frequent in the RG, but other complication frequencies were not significantly different in the 2 groups. Postoperative serum thyroglobulin levels were similar in 2 groups, and short-term follow-up (1 year) revealed no recurrence by sonography and no abnormal uptake during radioactive iodine therapy in either group., Conclusions: The application of robotic technology to endoscopic thyroidectomy could overcome the limitations of conventional endoscopic surgery during the surgical management of PTMC.