Age of Information for Short-Packet Covert Communication with Time Modulated Retrodirective Array

In this paper,the covert age of information(CAoI),which characterizes the timeliness and covertness performance of communication,is first investigated in the short-packet covert communication with time modulated retrodirective array(TMRDA).Specifically,the TMRDA is designed to maximize the antenna gain in the target direction while the side lobe is sufficiently suppressed.On this basis,the covertness constraint and CAoI are derived in closed form.To facilitate the covert transmission design,the transmit power and block-length are jointly optimized to minimize the CAoI,which demonstrates the trade-off between covertness and timelessness.Our results illustrate that there exists an optimal block-length that yields the minimum CAoI,and the presented optimization results can achieve enhanced performance compared with the fixed block-length case.Additionally,we observe that smaller beam pointing error at Bob leads to improvements in CAoI.

Effect of ankle versus thigh tourniquets on post-operative pain in foot and ankle surgery

BACKGROUND Tourniquets are commonly used in elective extremity orthopaedic surgery to reduce blood loss,improve visualization in the surgical field,and to potentially reduce surgical time.There is a lack of consensus in existing guidelines regarding the optimal tourniquet pressure,placement site,and duration of use.There is a paucity of data on the relationship between the site of a tourniquet and postoperative pain in foot and ankle surgery.AIM To explore the relationship between tourniquet site and intensity of post-operative pain scores in patients undergoing elective foot and ankle surgery.METHODS Retrospective analysis of prospectively collected data on 201 patients who underwent foot and ankle surgery in a single institution was undertaken.Intraoperative tourniquet duration,tourniquet pressure and site,and postoperative pain scores using Visual Analogue Score were collected in immediate recovery,at six hours and at 24 h post-op.Scatter plots were used to analyse the data and to assess for the statistical correlation between tourniquet pressure,duration,site,and pain scores using Pearson correlation coefficient.RESULTS All patients who underwent foot and ankle surgery had tourniquet pressure of 250 mmHg for ankle tourniquet and 300 mmHg for thigh.There was no correlation between the site of the tourniquet and pain scores in recovery,at six hours and after 24 h.There was a weak correlation between tourniquet time and Visual Analogue Score immediately post-op(r=0.14,P=0.04)but not at six or 24 h post-operatively.CONCLUSION This study shows that there was no statistically significant correlation between tourniquet pressure,site and postop pain in patients undergoing foot and ankle surgery.The choice of using a tourniquet is based on the surgeon's preference,with the goal of minimizing the duration of its application at the operative site.

Eucalyptus carbon stock estimation in subtropical regions with the modeling strategy of sample plots–airborne LiDAR–Landsat time series data

Updating eucalyptus carbon stock data in a timely manner is essential for better understanding and quantifying its effects on ecological and hydrological processes.At present,there are no suitable methods to accurately estimate the eucalyptus carbon stock in a large area.This research aimed to explore the transferability of the eucalyptus carbon stock estimation model at temporal and spatial scales and assess modeling performance through the strategy of combining sample plots,airborne LiDAR and Landsat time series data in subtropical regions of China.Specifically,eucalyptus carbon stock estimates in typical sites were obtained by applying the developed models with the combination of airborne LiDAR and field measurement data;the eucalyptus plantation ages were estimated using the random localization segmentation approach from Landsat time series data;and regional models were developed by linking LiDAR-derived eucalyptus carbon stock and vegetation age(e.g.,months or years).To examine the models’robustness,the developed models at the regional scale were transferred to estimate carbon stocks at the spatial and temporal scales,and the modeling results were evaluated using validation samples accordingly.The results showed that carbon stock can be successfully estimated using the age-based models(both age variables in months and years as predictor variables),but the month-based models produced better estimates with a root mean square error(RMSE)of 6.51 t⋅ha1 for Yunxiao County,Fujian Province,and 6.33 t⋅ha1 for Gaofeng Forest Farm,Guangxi Zhuang Autonomous Region.Particularly,the month-based models were superior for estimating the carbon stocks of young eucalyptus plantations of less than two years.The model transferability analyses showed that the month-based models had higher transferability than the year-based models at the temporal scale,indicating their possibility for analysis of carbon stock change.However,both the month-based and year-based models expressed relatively poor transferability at a spatial scale.This study provides new insights for cost-effective monitoring of carbon stock change in intensively managed plantation forests.

Time of surgery and surgeon level in supracondylar humerus fractures in pediatric patients:A retrospective study

BACKGROUND Supracondylar humerus fractures account for more than 60%of all elbow fractures and about 1/5 of all pediatric fractures.Unfortunately,these fractures can be associated with risk of complications including neurovascular injuries,malunions and limb deformities.Controversy exists regarding the effect of time of surgical intervention and/or level of surgeon performing the surgery on outcome of these fractures.AIM To determine whether time of surgical intervention and/or surgeon level influence the outcomes of surgically managed pediatric supracondylar humerus fractures.METHODS We retrospectively studied 155 pediatric patients presenting with a supracondylar humerus fracture in a level 1 trauma center from January 2006 to December 2019.The data extracted included demographic data,fracture characteristics,surgical data,and follow-up outcomes.The collected data was analyzed and P values of<0.05 were considered statistically significant.RESULTS Of the cohort,11%of patients had documented post-operative complications,of which the majority occurred in surgeries performed after day time working hours and in fractures requiring open reduction.While the lowest complication rate was found in surgeries performed by pediatric orthopaedic surgeons,this did not reach statistical significance.CONCLUSION In pediatric patients undergoing surgery for supracondylar fractures,we found a higher complication rate when surgeries were not performed during working hours.Surgeon level and training had no significant effect on the risk of post-operative complications.

Apatite Fission Track Ages in the Duolong Ore District and the Uplift Time of the Qiangtang Terrrane, Tibet

Objective Fission track （FT） analysis has developed into one of the most useful techniques throughout the geologic community to reconstruct low-temperature thermal historyof rocks over geological time （Reiners et al., 2005）. The FT method is based on the accumulation of narrow damage trails （i.e., fission tracks） in uranium-rich mineral grains （e.g., apatite, zircon, titanite） and natural glasses, which form as a result of spontaneous nuclear fission decay of 238U in nature. Apatite Fission Track （AFT） has been used in many places in Tibet to study the Qinghai- Tibetan Plateanuplifl-exhumation history. However, few AFT studies have been reported in the Duolong ore district. The Duolong ore district is one of the most important ore districts in the Bangong Co-Nujiang metallogenic belt, Tibet （Lin Bin et al., 2017） and the uplift-exhumation of the Duolong ore district is closely related to the evolution of the Qiangtang Basin. Therefore, AFT of the Duolong ore district will provide important information about the uplift-exhumation history of the Duolong ore district and the Qiangtang Basin.

New Zircon U-Pb Age of the Babu Ophiolites in Southeast Yunnan,China and Constrains of Plate Subduction Time

Objective The Babu ophiolite in Malipo County of southeastern Yunnan is interpreted as remanant ocean crust and represents a possible branch of Paleo-Tethyan Ocean in South China. It consists mainly of mafic and ultramafic rocks. These rocks are very important to understand the evolution of the Paleo-Tethyan Ocean. However, the Babu ophiolite is still disputed and the mafic and ultramafic rocks have been inferred to be part of the Emeishan large igneous province （LIP） by some researchers. In this paper, we present zircon U-Pb data on the metabasalts in Malipo to reveal the formation time of mafic and ultramafic rocks and their tectonic nature.

Age-Driven Joint Sampling and Non-Slot Based Scheduling for Industrial Internet of Things

Effective control of time-sensitive industrial applications depends on the real-time transmission of data from underlying sensors.Quantifying the data freshness through age of information(AoI),in this paper,we jointly design sampling and non-slot based scheduling policies to minimize the maximum time-average age of information(MAoI)among sensors with the constraints of average energy cost and finite queue stability.To overcome the intractability involving high couplings of such a complex stochastic process,we first focus on the single-sensor time-average AoI optimization problem and convert the constrained Markov decision process(CMDP)into an unconstrained Markov decision process(MDP)by the Lagrangian method.With the infinite-time average energy and AoI expression expended as the Bellman equation,the singlesensor time-average AoI optimization problem can be approached through the steady-state distribution probability.Further,we propose a low-complexity sub-optimal sampling and semi-distributed scheduling scheme for the multi-sensor scenario.The simulation results show that the proposed scheme reduces the MAoI significantly while achieving a balance between the sampling rate and service rate for multiple sensors.

Exploring ideal operative time for best outcomes in gastric cancer surgery:A multi-institutional study based on KLASS-07 database

Objective:While a rushed operation can omit essential procedures,prolonged operative time results in higher morbidity.Nevertheless,the optimal operative time range remains uncertain.This study aimed to estimate the ideal operative time range and evaluate its applicability in laparoscopic cancer surgery.Methods:A prospectively collected multicenter database of 397 patients who underwent laparoscopic distal gastrectomy were retrospectively reviewed.The ideal operative time range was statistically calculated by separately analyzing the operative time of uneventful surgeries.Finally,intraoperative and postoperative outcomes were compared among the shorter,ideal,and longer operative time groups.Results:The statistically calculated ideal operative time was 135.4-165.4 min.The longer operative time(LOT)group had a lower rate of uneventful,perfect surgery than the ideal or shorter operative time(IOT/SOT)group(2.8%vs.8.8%and 2.2%vs.13.4%,all P<0.05).Longer operative time increased bleeding,postoperative morbidities,and delayed diet and discharge(all P<0.05).Particularly,an uneventful,perfect surgery could not be achieved when the operative time exceeded 240 min.Regardless of ideal time range,SOT group achieved the highest percentage of uneventful surgery(13.4%),which was possible by surgeon's ability to retrieve a higher number of lymph nodes and perform≥150 gastrectomies annually.Conclusions:Operative time longer than the ideal time range(especially≥240 min)should be avoided.If the essential operative procedure were faithfully conducted without compromising oncological safety,an operative time shorter than the ideal range leaded to a better prognosis.Efforts to minimize operative time should be attempted with sufficient surgical experience.

Radiation therapy prior to a pancreaticoduodenectomy for adenocarcinoma is associated with longer operative times and higher blood loss

BACKGROUND Pancreatic adenocarcinoma is currently the fourth leading cause of cancer-related deaths in the United States.In patients with“borderline resectable”disease,current National Comprehensive Cancer Center guidelines recommend the use of neoadjuvant chemoradiation prior to a pancreaticoduodenectomy.Although neoadjuvant radiotherapy may improve negative margin resection rate,it is theorized that its administration increases operative times and complexity.AIM To investigate the association between neoadjuvant radiotherapy and 30-d morbidity and mortality outcomes among patients receiving a pancreaticoduodenectomy for pancreatic adenocarcinoma.METHODS Patients listed in the 2015-2019 National Surgery Quality Improvement Program data set,who received a pancreaticoduodenectomy for pancreatic adenocarcinoma,were divided into two groups based off neoadjuvant radiotherapy status.Multivariable regression was used to determine if there is a significant correlation between neoadjuvant radiotherapy,perioperative blood transfusion status,total operative time,and other perioperative outcomes.RESULTS Of the 11458 patients included in the study,1470(12.8%)underwent neoadjuvant radiotherapy.Patients who received neoadjuvant radiotherapy were significantly more likely to require a perioperative blood transfusion[adjusted odds ratio(aOR)=1.58,95%confidence interval(CI):1.37-1.82;P<0.001]and have longer surgeries(insulin receptor-related receptor=1.14,95%CI:1.11-1.16;P<0.001),while simultaneously having lower rates of organ space infections(aOR=0.80,95%CI:0.66-0.97;P=0.02)and pancreatic fistula formation(aOR=0.50,95%CI:0.40-0.63;P<0.001)compared to those who underwent surgery alone.CONCLUSION Neoadjuvant radiotherapy,while not associated with increased mortality,will impact the complexity of surgical resection in patients with pancreatic adenocarcinoma.

Impact of interval between neoadjuvant chemoradiotherapy and surgery in rectal cancer patients

BACKGROUND Epidemiologically,in China,locally advanced rectal cancer is a more common form of rectal cancer.Preoperative neoadjuvant concurrent chemoradiotherapy can effectively reduce the size of locally invasive tumors and improve disease-free survival(DFS)and pathologic response after surgery.At present,this modality has become the standard protocol for the treatment of locally advanced rectal cancer in many centers,but the optimal time for surgery after neoadjuvant therapy is still controversial.AIM To investigate the impact of time interval between neoadjuvant therapy and surgery on DFS and pathologic response in patients with locally advanced rectal cancer.METHODS A total of 231 patients who were classified as having clinical stage II or III advanced rectal cancer and underwent neoadjuvant chemoradiation followed by surgery at the National Cancer Center/Cancer Hospital,Chinese Academy of Medical Sciences and Peking Union Medical College from November 2014 to August 2017 were involved in this retrospective cohort study.The patients were divided into two groups based on the different time intervals between neoadjuvant therapy and surgery:139(60.2%)patients were in group A(≤9 wk),and 92(39.2%)patients were in group B(>9 wk).DFS and pathologic response were analyzed as the primary endpoints.The secondary endpoints were postoperative complications and sphincter preservation.RESULTS For the 231 patients included,surgery was performed at≤9 wk in 139(60.2%)patients and at>9 wk in 92(39.8%).The patients’clinical characteristics,surgical results,and tumor outcomes were analyzed through univariate analysis combined with multivariate regression analysis.The overall pathologic complete response(pCR)rate was 27.2%(n=25)in the longer time interval group(>9 wk)and 10.8%(n=15)in the shorter time interval group(≤9 wk,P=0.001).The postoperative complications did not differ between the groups(group A,5%vs group B,5.4%;P=0.894).Surgical procedures for sphincter preservation were performed in 113(48.9%)patients,which were not significantly different between the groups(group A,52.5%vs group B,43.5%;P=0.179).The pCR rate was an independent factor affected by time interval(P=0.009;odds ratio[OR]=2.668;95%CI:1.276-5.578).Kaplan-Meier analysis and Cox regression analysis showed that the longer time interval(>9 wk)was a significant independent prognostic factor for DFS(P=0.032;OR=2.295;95%CI:1.074-4.905),but the time interval was not an independent prognostic factor for overall survival(P>0.05).CONCLUSION A longer time interval to surgery after neoadjuvant therapy may improve the pCR rate and DFS but has little impact on postoperative complications and sphincter preservation.

Subtotal colonic bypass plus colostomy with antiperistaltic cecoproctostomy for the treatment of slow transit constipation in an aged population:A retrospective control study

AIM To compare the efficacy,improved quality of life,and prognosis in patients undergoing either subtotal colonic bypass with antiperistaltic cecoproctostomy(SCBAC) or subtotal colonic bypass plus colostomy with antiperistaltic cecoproctostomy(SCBCAC) for the treatment of slow transit constipation.METHODS Between October 2010 and October 2014,aged patients with slow transit constipation who were hospitalized and underwent laparoscopic surgery in our institute weredivided into two groups: the bypass group,15 patients underwent SCBAC,and the bypass plus colostomy group,14 patients underwent SCBCAC. The following preoperative and postoperative clinical data were collected: gender,age,body mass index,operative time,first flatus time,length of hospital stay,bowel movements(BMs),Wexner fecal incontinence scale,Wexner constipation scale(WCS),gastrointestinal quality of life index(GIQLI),numerical rating scale for pain intensity(NRS),abdominal bloating score(ABS),and ClavienDindo classification of surgical complications(CD) before surgery and at 3,6,12,and 24 mo after surgery.RESULTS All patients successfully underwent laparoscopic surgery without open surgery conversion or surgeryrelated death. The operative time and blood loss were significantly less in the bypass group than in the bypass plus colostomy group(P = 0.007). No significant differences were observed in first flatus time,length of hospital stay,or complications with CD > 1 between the two groups. No patients had fecal incontinence after surgery. At 3,6,and 12 mo after surgery,the number of BMs was significantly less in the bypass plus colostomy group than in the bypass group. The parameters at 3,6,12,and 24 mo after surgery in both groups significantly improved compared with the preoperative conditions(P < 0.05),except NRS at 3,6 mo after surgery in both groups,ABS at 12,24 mo after surgery and NRS at 12,24 mo after surgery in the bypass group. WCS,GIQLI,NRS,and ABS significantly improved in the bypass plus colostomy group compared with the bypass group at 3,6,12,and 24 mo after surgery(P < 0.05) except WCS,NRS at 3,6 mo after surgery and ABS at 3 mo after surgery. At 1 year after surgery,a barium enema examination showed that the emptying time was significantly better in the bypass plus colostomy group than in the bypass group(P = 0.007).CONCLUSION Laparoscopic SCBCAC is an effective and safe procedure for the treatment of slow transit constipation in an aged population and can significantly improve the prognosis. Its clinical efficacy is more favorable compared with that of SCBAC. Laparoscopic SCBCAC is a better procedure for the treatment of slow transit constipation in an aged population.

Should we resect colorectal cancer in patients over the age of 85?

BACKGROUND The prevalence of colorectal cancer in the elderly is rising,with increasing numbers of older patients undergoing surgery.However,there is a paucity of information on the surgical outcomes and operative techniques used in this population.AIM To evaluate the post-operative outcomes for patients≥85 years old following colorectal cancer resection as well as evaluating the outcomes of laparoscopic resection of colorectal cancer in patients over 85.METHODS Patients who underwent colorectal cancer resection at our institution between January 2010 and December 2018 were included.The study was divided into two parts.For part one,patients were divided into two groups based on age:Those age≥85 years old(n=48)and those aged 75-84 years old(n=136).Short term surgical outcomes and clinicopathological features were compared using appropriate parametric and non-parametric testing.For part two,patient’s over 85 years old were divided into two groups based upon operative technique:Laparoscopic(n=37)vs open(n=11)colorectal resection.Short-term postoperative outcomes of each approach were assessed.RESULTS The median length of stay between patients over 85 and those aged 75-85 was eight days,with no statistically significant difference between the groups(P=0.29).No significant difference was identified between the older and younger groups with regards to severity of complications(P=0.93),American Society of Anaesthesiologists grading(P=0.43)or 30-d mortality(2%vs 2%,P=0.96).Patients over 85 who underwent laparoscopic colorectal resection were compared to those who underwent an open resection.The median length of stay between the groups was similar(8 vs 9 d respectively)with no significant difference in length of stay(P=0.18).There was no significant difference in 30-d mortality rates(0%vs 9%,P=0.063)or severity of complication grades(P=0.46)between the laparoscopic and open surgical groups.CONCLUSION No significant short term surgical differences were identified in patients≥85 years old when compared to those 75-85 years old.There is no difference in short term surgical outcomes between laparoscopic or open colorectal resections in patients over 85.

New Evidence of Detrital Zircon Ages for the Final Closure Time of the Paleo-Asian Ocean in the Eastern Central Asian Orogenic Belt(NE China)

Objective The NE China is located in the eastern segment of the Central Asian Orogenic Belt（CAOB）,which is a large accretionary orogen between the Siberian Craton and the North China Craton（NCC）.Many researches have discussed about the evolution of the Paleo-Asian Ocean（PAO）in the eastern CAOB.However,

Impact of GPS Almanac Broadcast Strategy on the Signal Acquisition Time

This paper investigates the problem of almanac affecting the signal acquisition time with two constraints: different age of data and multi-sets of almanac. The contributions made in this paper include: 1) the exploiting of signal acquisition concept to extend well-known almanac function of predicting visible satellite and initializing signal acquisition to minimizing the signal acquisition time; 2) a model based on code phase and Doppler frequency to reflect the impact of multi-sets of almanac on the signal acquisition time; 3) the evaluation of the existing GPS almanac with different broadcast strategy. The theoretical analyses and simulations conducted on three sets of almanac show that the model proposed in this paper is general and efficient for almanac design and application.

Is it the time to reconsider the choice of valves for cardiac surgery： mechanical or bioprosthetic？

Valvular heart disease is a pathologic process involving one or more of the four valves(aortic,pulmonary,mitral and tricuspid)of the heart typified by stenosis or regurgitation and leading to patient symptoms.The most common causes are tissue degeneration,rheumatic fever and congenital heart diseases.Aortic valve replacement(AVR)using either mechanical or bioprosthetic(tissue)valves via open-heart surgical

Approaches on the Major Predictors of Blood Transfusion in Cardiovascular Surgery: A Systematic Review

Introduction: Experimental Clinical studies have shown that loss of up to 77.0% of red cell mass can be tolerated as long as it kept the blood volume. However, the blood volume loss of about 34.0% is fatal. The initial attention in patients with bleeding should be given to maintaining blood volume and oxygen transport. Thus, transfusions of allogeneic blood products are associated with an increased risk of morbidity and mortality in cardiac surgery. Some transfusion risk scores have been proposed for cardiac surgery patients. Objective: To review and discuss literature blood transfusion (blood components gradient) in cardiovascular surgery versus polytrauma, gastrointestinal bleeding, and neoplastic diseases. Methods: The model followed for the review was PRISMA. We used the databases as Scielo, Lilacs, Google Scholar, PubMed articles and works of scientific and doctoral theses master. Results: According to the discussion in the literature, the acute bleeding of large volumes is challenging to emergency services. Accordingly, the need to support hemotherapeutics led to the development of protocols for more rational utilization of the monitored blood components. Conclusion: Hemotherapy services have adopted a very dynamic approach to the clinical condition presented by patients, the need for four or more red blood cell units.

Effects of creative expression program on the event-related potential and task reaction time of elderly with mild cognitive impairment

Objectives:This study aimed to evaluate the effects of a 16-week creative expression intervention program(CrExp)on the event-related potential(ERP)and task reaction time in older individuals with mild cognitive impairment(MCI).Methods:This study is a randomized controlled clinical trial conducted in the Memory Center of Fujian Provincial hospital.Thirty-six MCI patients were randomly distributed into two groups.One group underwent a 16-week creative expression program(CrExp,n=18)and the other performed as a control group(CG,n=18)by general social activities.The amplitude and latency of ERP-P300 from the central(Cz),parietal(Pz),frontal(Fz)cortices and task reaction time(RT)were assessed at baseline,postinterventi on,and 24-week follow-up.Results:The CrExp group showed greater differences than CG of P300 latency in Cz(F=4.37,P=0.015),Pz(F=2.78,P=0.009),Fz(F=6.45,P=0.031)brain area after 16 weeks of intervention and in Fz(F=3.23,P=0.028),Cz(F=3.79,P=0.024),and Pz(F=5.60,P=0.036)at 24 weeks follow-up.Also,we analyzed the task reaction time between two groups and found that a shorten reaction time at postintervention(F=4.47,P=0.011)and 24 weeks follow-up(F=3.12,P=0.007)in the CrExp group.However,there was no difference in P300 amplitude in either brain area between the two groups.Conclusion:The electrophysiological results of the creative expression cognitive therapy group were more obvious than those of the general cognitive therapy group,and the latency and task reaction time may be considered as supported parameters in diagnosing the effects during non-drug therapy intervention in clinical practice.

The Optimization of Preventive Maintenance Scheduling for Production Machine of Production System in Finite Time Horizon

The recursion relation of preventive maintenance (PM) cycle is built up concerning the concept of effective age and age setback factor proposed in this paper, which illustrates the dynamic relationship between failure rate and preventive maintenance activity. And the nonlinear optimal PM policy model satisfying the reliability constraints in finite time horizon following Weibull distribution is proposed. The model built in this paper avoids the shortcoming of steady analytical PM model in infinite time horizon and can be used to aid scheduling the maintenance plan and providing decision supporting for job shop scheduling.

Outcomes of cardiac surgery in senior aged patients with ventricular dysfunction:analysis of a large national database

OBJECTIVE In patients undergoing cardiac surgery,reduced preoperative ejection fraction(EF)and senior age are associated with a worse outcome.As most outcome data available for these patients are mainly from Western surgical populations involving specific surgery types,our aim is to evaluate the real-world characteristics and perioperative outcomes of surgery in senior-aged heart failure patients with reduced EF across a broad range cardiac surgeries.METHODS Data were obtained from the China Heart Failure Surgery Registry(China-HFSR)database,a nationwide multicenter registry study in China's Mainland.Multiple variable regression analysis was performed in patients over 75 years old to identify risk factors associated with mortality.RESULTS From 2012 to 2017,578 senior-aged(>75 years)patients were enrolled in China HFSR,21.1%of whom were female.Isolated coronary bypass grafting(CABG)were performed in 71.6%of patients,10.1%of patients underwent isolated valve surgery and 8.7%received CABG combined with valve surgery.In-hospital mortality was 10.6%,and the major complication rate was 17.3%.Multivariate analysis identified diabetes mellitus(odds ratio(OR)=1.985),increased creatinine(OR=1.007),New York Heart Association(NYHA)Class III(OR=1.408),NYHA class IV(OR=1.955),cardiogenic shock(OR,6.271),and preoperative intra-aortic balloon pump insertion(OR=3.426)as independent predictors of in-hospital mortality.CONCLUSIONS In senior-aged patients,preoperative evaluation should be carefully performed,and strict management of reversible factors needs more attention.Senior-aged patients commonly have a more severe disease status combined with more frequent comorbidities,which may lead to a high risk in mortality.

Spine Surgery Profile in the Fourth Age

As the population of the United States undergoes significant qualitative and quantitative changes the healthcare needs of the population changes accordingly. Since the “old-old” ≥85 years sector of the population is growing fast we embarked on studying how spine surgery profile changes across age groups. Methods: A database of 6147 spine surgery patients operated in a tertiary care center in Middle Georgia between 2003 and 2009 was divided to four age groups. The threshold for old-old age was set at 75. The percentage of old-old patients was calculated and their spine surgery profile for the whole period was studied. Changes in spine surgery profile were evaluated in relation to age group and gender. Type of surgery was determined by ICD-9 code. Results: For the whole study period, the percentage of old-old spine surgery patients was 6.7%. The percentage of old-old spine surgery patients increased from 4.7% in 2003 to 7.3% in 2009. Females were preponderant in the later three age groups (53.8%, 53.2% and 55.0%) while males were more in the 2 = 1446.958, P = 0.000). The spine surgery profile for the whole study period was characterized by shifts in the ≥75 age group toward less primary fusions of the cervical and lumbar spine and more refusions of the lumbar spine, more intervertebral disk excisions and more canal exploratory operations in older-old patients. In addition to the age factor, the gender factor had an impact on the spine surgery profile. Statistically significant differences (P < 0.5) were noted between males and females in each age group. Conclusions: Spine surgery profile shows a tendency toward less invasive procedures in the older-old population unless indicated by previous surgery failures, upper neck injuries or osteoporosis-induced fractures.