Preoperative planning system for surgical robotics setup with kinematics and haptics

Recently, some useful robotic surgical systems have been developed and applied in many surgical situations. Systems such as the da Vinci surgical system of Intuitive Surgical Inc., which facilitates minimally invasive surgery with increased dexterity, are commercially available. Preoperative simulation and planning of surgical robot setups should accompany advanced robotic surgery if their advantages are to be further pursued. Feedback from the planning system will play an essential role in computer-aided robotic surgery in addition to preoperative detailed geometric information from patient CT/MRI images. Surgical robot setup simulation systems for appropriate trocar site placement have been developed especially for abdominal surgery. The motion of the surgical robot can be simulated and rehearsed with kinematic constraints at the trocar site, and the inverse-kinematics of the robot. Results from simulation using clinical patient data verify the effectiveness of the proposed system.     

Effects of autotransfusion of mediastinal shed blood on biochemical markers of myocardial damage in coronary surgery

BACKGROUND: Previous studies have shown conflicting results regarding the effect of autotransfusion of mediastinal shed blood after coronary artery bypass grafting (CABG) on the serum levels of myocardial band (MB) isoenzymes of creatine kinase (CK-MB) and cardiac troponins. The effect of autotransfusion on serum levels of human heart fatty acid binding protein (H-FABP), another marker of myocardial necrosis, has not been studied. The aim of the present study was to investigate the effects of autotransfusion of mediastinal shed blood on the serum levels of CK-MB, cardiac troponin T (cTnT), and H-FABP after uncomplicated primary CABG. METHODS: Fifty patients were randomized to post-operative autotransfusion of mediastinal shed blood or no autotransfusion. Blood samples for the analysis of the biochemical markers of myocardial damage were drawn pre-operatively and 1, 4, 12, 24, 48, and 72 h after the termination of cardiopulmonary bypass. Samples from the mediastinal shed blood were collected after 1 and 4 h. RESULTS: The levels of the biochemical markers of myocardial injury were all markedly elevated in mediastinal shed blood. Autotransfusion did not significantly affect the serum levels of cTnT or H-FABP. However, during the early post-operative hours, there was a trend towards a higher level of cTnT and H-FABP in the autotransfusion group. During the first 24 h after surgery, the autotransfusion group had a significantly higher serum level of CK-MB. CONCLUSION: Post-operative autotransfusion of mediastinal shed blood may contribute to elevated serum levels of biochemical markers of myocardial injury.     

Extradural thoracic arachnoid cyst. Case report and review of the literature

OBJECTIVE: To report an unusual and asymptomatic cause of cord compression treated surgically with good clinical outcome. METHODS AND MATERIAL: We report a case of extradural arachnoid cyst in the thoracic region and review the literature on the clinical, neuroradiologic and therapeutic features. RESULTS: A 17-year-old man, with unremarkable past medical history was referred to our institution of Neurosurgery, CHU Mohammed-VI, Marrakech, with progressive spastic paraparesis. Magnetic resonance imaging (MRI) showed a posterior extradural cystic lesion in the thoracic region from T6-T7 thoracic vertebra. The cyst was completely removed by posterior approach. An arachnoid cyst was confirmed at the histological study. Neurological symptoms improved after surgery. CONCLUSION: Given its infrequency, the diagnosis of arachnoid cyst should be suspected when a cystic lesion causes cord compression. Surgery is the treatment of choice, providing good clinical outcome.     

Travel distance, age, and sex as factors in follow-up visit compliance in the post-gastric bypass population

BACKGROUND: There is no consensus regarding the optimal rate of follow-up in the post-bariatric surgery patient population. METHODS: The records of all patients who underwent laparoscopic Roux-en-Y gastric bypass from 2001 to 2003 were reviewed. Using patient zip codes, travel distances were calculated between the patients' places of residence and our clinic. Patients were then assigned to 1 of 3 cohorts according to the following distances: (1) < 50 miles, (2) 50 to 100 miles, and (3) > 100 miles. Patient compliance with follow-up appointments at 3 weeks, 3 months, 6 months, 9 months, and 12 months was analyzed. Linear trends were identified using the Mantel-Haenszel test. Age and sex were analyzed as possible predictors of compliance using the chi(2) test. P values < .05 were considered statistically significant. RESULTS: The study group comprised 150 patients (127 females and 23 males). The 3 cohorts contained 115, 21, and 14 patients, respectively. All patients in each cohort were compliant with the 3-week follow-up appointment. Although there were differences in compliance between cohorts at each of the remaining appointments, only the 9-month (70.3% vs 61.9% vs 35.7%) visit showed statistical significance (P = .035). The 6-month visit trended toward significance (85.2% vs 76.2% vs 64.3%; P = .088). Males were more likely to be compliant with the 12-month follow-up (P = .040). When controlling for sex, travel distance was also a predictor of compliance at this follow-up visit (P = .024). Age was not predictive of compliance (P = .827). CONCLUSION: Based on our findings, we conclude that travel distance from the clinic does not significantly affect compliance at the initial follow-up, 3-month, and 12-month appointments. However, distance does tend to affect compliance at the 6-month appointment and significantly affects compliance at the 9-month appointment. Males are more likely to be compliant at the 12 month follow-up visit. We must continue to strive for 100% follow-up in our post-bariatric surgery patients.     

Comparison of propofol/remifentanil and sevoflurane/remifentanil for maintenance of anaesthesia for elective intracranial surgery

Background. Propofol and sevoflurane are suitable agents formaintenance of anaesthesia during neurosurgical procedures.We have prospectively compared these agents in combination withthe short-acting opioid, remifentanil. Methods. Fifty unpremedicated patients undergoing elective craniotomyreceived remifentanil 1 µg kg^–1 followed by an infusioncommencing at 0.5 µg kg^–1 min^–1 reducing to0.25 µg kg^–1 min^–1 after craniotomy. Anaesthesiawas induced with propofol, and maintained with either a target-controlledinfusion of propofol, minimum target 2 µg ml^–1 orsevoflurane, initial concentration 2%_ET. Episodes of mean arterialpressure (MAP) more than 100 mm Hg or less than 60 mm Hg formore than 1 min were defined as hypertensive or hypotensiveevents, respectively. A surgical assessment of operating conditionsand times to spontaneous respiration, extubation, obey commandsand eye opening were recorded. Drug acquisition costs were calculated. Results. Twenty-four and twenty-six patients were assigned topropofol (Group P) and sevoflurane anaesthesia (Group S), respectively.The number of hypertensive events was comparable, whilst morehypotensive events were observed in Group S than in Group P(P=0.053, chi-squared test). As rescue therapy, more labetolol[45 (33) vs 76 (58) mg, P=0.073] and ephedrine [4.80 (2.21)vs 9.78 (5.59) mg, P=0.020] were used in Group S. Between groupdifferences in recovery times were small and clinically unimportant.The combined hourly acquisition costs of hypnotic, analgesic,and vasoactive drugs appeared to be lower in patients maintainedwith sevoflurane than with propofol. Conclusion. Propofol/remifentanil and sevoflurane/remifentanilboth provided satisfactory anaesthesia for intracranial surgery.     

Role of age on the outcome of liver surgery. A single institution experience

Objective: The aim of the present study was to evaluate the role of age on different types of liver surgery. Methodology: Between 2002 and 2007, 50 patients underwent a variety of liver surgical procedures due to primary or metastatic tumours. Of these, 24 were 70 years old or older, and 26 patients were younger than 70 years old at the time of the operation. Results: Among the patients included in the study, 22 underwent radiofrequency ablation. Another 11 underwent non‐anatomical liver resection. The remaining 17 patients underwent liver resection, with more than three segments resected. The type of procedure, duration of operation, estimated blood loss, and postoperative death and morbidity rates were not significantly different between the two groups. The mean survival of patients that underwent radiofrequency ablation or non‐anatomical resection was not significantly different between the two groups. However, in the patients in which liver resection was performed, mean survival was significantly greater in the younger group. Conclusions: These results indicate that hepatic resection is a safe and feasible procedure in elderly patients. The postoperative outcome in this age group is comparable of that of younger patients.     

Are Coronary Angiograms of Value in the Risk Stratification of Patients Undergoing Coronary Artery Bypass Surgery?

INTRODUCTION

There are currently more than 20 risk-scoring systems that attempt to predict peri-operative mortality following coronary artery bypass surgery (CABG). All these scoring systems use objective criteria to assess operative risk. Angiographic data are currently not included in any of these systems. This pilot study assessed the value of coronary angiography in predicting peri-operative mortality following CABG.

PATIENTS AND METHODS

Fourteen patients who died following first-time isolated CABG surgery were identified. These were matched with 14 patients of similar age, sex, left ventricle function and European System for Cardiac Operative Risk Evaluation (EuroSCORE). A panel of 25 clinicians were given details of the patients'' age, sex, diabetic status, family history, smoking history, hypertensive status, lipid status, pre-operative symptoms, left ventricle ejection fraction and weight and shown the coronary angiograms of the patient. They were asked to predict the outcome following CABG for each patient.

RESULTS

Receiver operator characteristic curves were constructed and the area under the curves calculated and analysed using a commercially available statistical package (PRISM). The area under the curve for the group was 0.6820 for the group. Consultant clinicians achieved an area of 0.6789 versus their trainees 0.6844 (P = NS). The cardiologists achieved an area of 0.7063 versus the cardiothoracic surgeons 0.6491 (P = NS).

CONCLUSIONS

Despite the EuroSCORE predicting equal risk for the two groups of patients, it would appear that clinicians are able to identify individual higher risk patients by assessing pre-operatively the quality of the patient'' coronary vasculature. Although the clinicians were able to predict individual patient mortality better than the EuroSCORE, the area under the curve indicates that it is not a robust method and clinicians, with all the clinical information to hand, are only moderately good at predicting the outcome following coronary artery bypass surgery.     

内镜腔内手术的实验研究

目的探讨内镜腔内手术的可行性. 方法 6只家猪经皮建立胃内通道,腹腔镜引导下胃内模拟缝合止血操作实验. 结果 6只家猪均很好地耐受了手术.术后开腹检查所有胃壁缝合处无渗漏及其它脏器损伤.建立胃内通道时间、胃内缝合时间及总手术时间分别为(60.5±12.2)min、(26.5±5.78)min和(92.1±15.0)min. 结论内镜腔内手术在技术上是可行的.