Incorporating an Exercise Detection,Grading, and Hormone Dosing Algorithm Into the Artificial Pancreas Using Accelerometry and Heart Rate

In this article, we present several important contributions necessary for enabling an artificial endocrine pancreas (AP) system to better respond to exercise events. First, we show how exercise can be automatically detected using body-worn accelerometer and heart rate sensors. During a 22 hour overnight inpatient study, 13 subjects with type 1 diabetes wearing a Zephyr accelerometer and heart rate monitor underwent 45 minutes of mild aerobic treadmill exercise while controlling their glucose levels using sensor-augmented pump therapy. We used the accelerometer and heart rate as inputs into a validated regression model. Using this model, we were able to detect the exercise event with a sensitivity of 97.2% and a specificity of 99.5%. Second, from this same study, we show how patients’ glucose declined during the exercise event and we present results from in silico modeling that demonstrate how including an exercise model in the glucoregulatory model improves the estimation of the drop in glucose during exercise. Last, we present an exercise dosing adjustment algorithm and describe parameter tuning and performance using an in silico glucoregulatory model during an exercise event.     

Obesity and Obesity Shape Markedly Influence Spine Biomechanics: A Subject-Specific Risk Assessment Model

Underlying mechanisms of obesity-related back pain remain unexplored. Thus, we aim to determine the effect of obesity and its shapes on the spinal loads and the associated risks of injury. Obesity shapes were initially constructed by principal component analysis based on datasets on 5852 obese individuals. Spinal loads, cycles to vertebral failure and trunk stability margin were estimated in a subject-specific trunk model taking account of personalized musculature, passive ligamentous spine, obesity shapes, segmental weights, spine kinematics and bone mineral density. Three obesity shapes (mean and extreme abdominal circumferences) at three body weights (BWs) of 86, 98 and 109 kg were analyzed. Additional BW (12 kg) increased spinal loads by ~11.8%. Higher waist circumferences at identical BW increased spinal forces to the tune of ~20 kg additional BW and the risk of vertebral fatigue compression fracture by 3–7 times when compared with smaller waist circumferences. Forward flexion, greater BW and load in hands increased the trunk stability margin. Spinal loads markedly increased with BW, especially at greater waist circumferences. The risk of vertebral fatigue fracture also substantially increased at greater waist circumferences though not at smaller ones. Obesity and its shape should be considered in spine biomechanics.     

Timing of Surgery and the Role of Adjuvant Radiotherapy in Ewing Sarcoma of the Chest Wall: A Single-institution Experience

Background

Ewing sarcoma (ES) is the most common chest wall malignancy in adolescents. Current therapy incorporates chemotherapy to treat systemic disease and radiotherapy to assist with local control. We sought to evaluate the timing of surgery and role of adjuvant radiotherapy.

Methods

We reviewed the St. Jude Children??s Research Hospital chest wall ES experience from 1979 to 2009. Patient demographics, tumor characteristics, treatment variables, and outcomes were analyzed with respect to timing of surgery and use of adjuvant radiotherapy.

Results

Our cohort consisted of 36 patients with chest wall ES; median follow-up was 14.2?years, and 15-year estimate of overall survival was 66?%. In patients with localized disease, the timing of surgery (up-front vs. delayed) did not impact margin negativity or the use of adjuvant radiotherapy, but it did decrease the extent of chest wall resection. When considering radiotherapy in patients with localized disease, we found that patients who did not receive radiotherapy had smaller tumor size (median 6 vs. 10?cm) (p?=?0.04) and were more likely to have had negative margins (p?=?0.01) than patients who received adjuvant radiotherapy. One patient in each group developed a locoregional recurrence. The 15-year estimated of overall survival for patients who received adjuvant radiotherapy was 80 versus 100?% for those who did not.

Conclusions

Delayed surgery decreased the extent of chest wall resection and helped define a patient population with favorable tumor biology. Patients with complete pathologic responses to chemotherapy, and those with tumors <8?cm and negative surgical margins may be spared adjuvant radiotherapy without any decrement in overall survival.     

The incidence of urethral stricture and bladder neck contracture with transurethral resection vs. holmium laser enucleation of prostate: A matched,dual-center study

IntroductionUrethral strictures (US) and bladder neck contracture (BNC) are common, long-term complications of transurethral prostate surgery. We aimed to compare transurethral resection of the prostate (TURP) and holmium laser enucleation of the prostate (HoLEP) regarding incidence of US or BNC and identify possible risk factors.MethodsA retrospective review of patients who underwent TURP and HoLEP with followup data of at least one year in two separate institutions was performed. The incidence of postoperative US or BNC in both groups was compared. Bivariate and multivariate analysis of risk factors in both cohorts with US or BNC were performed.ResultsThe study included 208 patients: 101 and 107 patients in the TURP and HoLEP arms, respectively. The two groups were matched for age and prostate size. Eight (7.92%) and five (4.72%) patients in the TURP and HoLEP arms, respectively, developed US (p=0.3423), while two (1.87%) patients in the HoLEP arm had BNC (p=0.2634). Of the eight patients with the US in the TURP arm, six (9.8%) had bipolar TURP, while two (5%) had monopolar TURP. Multivariate analysis showed that larger prostate volume (hazard ratio [HR] 1.22, 95% confidence interval [CI] 1.05, 1.41, p=0.0066) and longer operative time (HR 1.84, 95% CI 1.76, 1.93, p=0.0015) were associated with risk of US/BNC.ConclusionsThere is no significant difference between TURP and HoLEP regarding incidence of US or BNC, although there is a tendency towards a higher rate of US associated with bipolar TURP. Increased prostate volume and operative time are possible risk factors.

KEY MESSAGES

• We compared TURP and HoLEP regarding their incidence of US or BNC with matching patients for age and prostate volume and identified possible risk factors.
• The US incidence was comparable, although the incidence within the TURP arm was higher with bipolar than monopolar TURP.
• The BNC incidence was 1.87% in the HoLEP arm, while none of the patients in the TURP arm developed BNC (statistically insignificant).
• Multivariate analysis showed that larger prostate volume and longer operative time were associated with higher risk of US/BNC.

     

SPERM CRYOPRESERVATION PRACTICES AMONG ADOLESCENT CANCER PATIENTS AT RISK FOR INFERTILITY

To assess sperm cryopreservation among males newly diagnosed with cancer aged 13 years and older, attending oncologists assigned infertility risk (yes/no) to patients and reported whether their patients engaged in sperm cryopreservation. Only 28.1% of informed at-risk patients banked sperm. Utilization of sperm banking was significantly associated with a diagnosis of central nervous system (CNS) malignancy or non-CNS solid tumor diagnosis, higher socioeconomic status, and not being a member of an Evangelical religious group. These results suggest that sperm banking is underutilized among adolescent males newly diagnosed with cancer, and that strategies to increase the engagement in this fertility preservation method are needed.     

Evaluation of limbal and pars plana silicone oil removal in aphakic eyes

Purpose: To compare limbal and pars plana silicone oil removal (SOR) in aphakic eyes and to evaluate the acute effect of silicone oil flow to the corneal endothelium. Methods: Sixteen aphakic patients with silicone oil endotamponade requiring SOR were recruited for this prospective study and randomly scheduled for limbal or pars plana SOR. The central corneal thickness (CCT), visual acuity (VA) and intraocular pressure were measured preoperatively, on the first postoperative day and 4 months after surgery. Endothelial cell density (ECD) was measured preoperatively and at the end of follow‐up. The in vitro study was performed on ten enucleated porcine eyes. Corneoscleral discs were prepared and fixed on artificial anterior chamber followed by 2.5‐mm limbal incision and 5‐ml silicone oil injection in six cases and 5 ml balanced salt solution (BSS) in four cases. Results: The ECD decreased by 239.2 ± 86.7 (13.9%) and 86.7 ± 22.4 cells/mm² (5%) after limbal (n = 8) and pars plana SOR (n = 8), respectively (p < 0.001 for both). The difference between the groups was significant (p < 0.001). A significant increase in CCT and corresponding decrease in VA was noted on the first postoperative day using both procedures. At the end of follow‐up, the CCT and VA were comparable to initial values. Postoperative hypotony (≤6 mmHg) was observed more frequently after limbal SOR. In the experiment, lamellar abrasions of corneal endothelium were observed after silicone oil injection, whereas no changes were observed after BSS injection. Conclusion: Limbal SOR causes more considerable damage to the corneal endothelium than the pars plana approach because of mechanical abrasion.     

Characterization of urgent versus nonurgent early readmissions (<30 days) following primary bariatric surgery: a single-institution experience

BackgroundStudies on early postoperative readmissions after bariatric surgery (BS) have examined readmissions as a single entity, regardless of urgency. Strategies to lower nonurgent readmissions would reduce unnecessary hospital utilization.ObjectivesTo identify predictors of urgent readmissions (UR) versus nonurgent readmissions (NUR) at 30 days post-BS.SettingSingle academic institution.MethodsPatients undergoing primary BS over 2 years (n = 589) were retrospectively reviewed. Baseline demographic, medical, and hospitalization data were compared between readmitted patients, stratified by urgency, and nonreadmitted patients. Multivariate regression models of UR and NUR were created using variables with a P value ≤ .2 on univariate analyses. A P value ≤ .05 was considered statistically significant.ResultsThere were 39 documented instances of 30-day readmissions, of which 44% (n = 17) were NUR; NUR patients were more likely to be female (100% versus 78.2% male; P = .03) and trended toward being younger, experiencing ≥2 perioperative complications, and having a longer index hospital length of stay (LOS). Patients with URs had a higher baseline BMI (52.5 ± 11.4 kg/m² versus 48.7 ± 8.3 kg/m², respectively; P = .04), were more likely to have sleep apnea (77.3% versus 56.1%, respectively; P = .05), had a longer LOS (3 versus 2 d, respectively; P = .007), and were more likely to have ≥2 postoperative complications (46% versus 17.0%, respectively; P = .003) compared with those with an NUR. Independent predictors of NUR included public insurance (odds ratio [OR] = 3.7; 95% confidence interval [CI], 1.17–11.67; P = .03), younger age (OR = 1.05; 95% CI, 1–1.01; P = .04), and female sex, while URs were independently predicted by LOS (OR = 1.3; 95% CI, 1.04–1.5; P = .02).ConclusionsPublic insurance appears to be associated with NURs, while LOS predicts URs after BS. This suggests an important dichotomy within readmissions based on urgency, which has important implications for targeted quality initiatives.