Torin P. Fitton

Application of haptic feedback to robotic surgery.

Robotic surgical systems have greatly contributed to the advancement of minimally invasive endoscopic surgery. However, current robotic systems do not provide tactile or haptic feedback to the operating surgeon. Under certain circumstances, particularly with the manipulation of delicate tissues and suture materials, this may prove to be a significant irritation. We hypothesize that haptic feedback, in the form of sensory substitution, facilitates the performance of surgical knot tying. This preliminary study describes evidence that visual sensory substitution permits the surgeon to apply more consistent, precise, and greater tensions to fine suture materials without breakage during robot-assisted knot tying.

Aortic Root Replacement in 372 Marfan Patients: Evolution of Operative Repair Over 30 Years

BACKGROUND We reviewed the evolution of practice and late results of aortic root replacement (ARR) in Marfan syndrome patients at our institution. METHODS A retrospective clinical review of Marfan patients undergoing ARR at our institution was performed. Follow-up data were obtained from hospital and office records and from telephone contact with patients or their physicians. RESULTS Between September 1976 and September 2006, 372 Marfan syndrome patients underwent ARR: 269 had a Bentall composite graft, 85 had valve-sparing ARR, 16 had ARR with homografts, and 2 had ARR with porcine xenografts. In the first 24 years of the study, 85% received a Bentall graft; during the last 8 years, 61% had a valve-sparing procedure. There was no operative or hospital mortality among the 327 patients who underwent elective repair; there were 2 deaths among the 45 patients (4.4%) who underwent emergent or urgent operative repair. There were 74 late deaths (70 Bentalls, 2 homograft, and 2 valve-sparing ARRs). The most frequent causes of late death were dissection or rupture of the residual aorta (10 of 74) and arrhythmia (9 of 74). Of the 85 patients who had a valve-sparing procedure, 40 had a David II remodeling operation; there was 1 late death in this group, and 5 patients required late aortic valve replacement for aortic insufficiency. A David I reimplantation procedure using the De Paulis Valsalva graft has been used exclusively since May 2002. All 44 patients in this last group have 0 to 1+ aortic insufficiency. CONCLUSIONS Prophylactic surgical replacement of the ascending aorta in patients with Marfan syndrome has low operative risk and can prevent aortic catastrophe in most patients. Valve-sparing procedures, particularly using the reimplantation technique with the Valsalva graft, show promise but have not yet proven as durable as the Bentall.

Aortic Valve Replacement and Concomitant Mitral Valve Regurgitation in the Elderly Impact on Survival and Functional Outcome

Background—The impact of mitral regurgitation (MR) on elderly patients (≥70 years) undergoing isolated aortic valve replacement (AVR) is not clearly defined. This study investigates the long-term effects of preoperative, moderate MR on survival and functional outcome in elderly AVR patients. Methods and Results—A retrospective review identified 408 consecutive elderly patients who underwent isolated AVR from January 1983 to February 2004. The pathologic etiology of MR was determined on preoperative echocardiogram, and patients were stratified into no/mild MR (Group I; n =338) versus moderate MR (Group II; n =70). Follow-up was 95.1% complete. Functional outcome was evaluated using the Short Form-12 questionnaire. On univariate analysis, Groups I and II differed in incidence of previous myocardial infarction (13.9% versus 28.6%; P=0.004), hyperlipidemia (18.7% versus 33.3%; P=0.009), and congestive heart failure (50.0% versus 70.0%; P=0.002). On multivariate analysis, moderate MR was an independent risk factor impacting long-term survival (P=0.04). Actuarial survival at 1, 5, and 10 years for Group I was 93.8%, 73.3%, and 40.1% versus 92.3%, 58.2%, and 14.6% for Group II (P=0.04). Available postoperative echocardiograms for Group II (n =37) demonstrated improvement in MR in 81.8% of functional MR patients. However, MR persisted or worsened in 65.4% of patients with intrinsic mitral valve disease (myxomatous, calcific, or ischemic MR). Functional outcomes showed 77% of Group I versus 78.6% of Group II rated their health as good to excellent post-AVR. Conclusions—Moderate MR is an independent risk factor impacting long-term survival in elderly patients undergoing AVR. Therefore, patients with intrinsic mitral valve disease should be considered for concomitant MV surgery.

A 32-Year Experience with Surgical Repair of Sinus of Valsalva Aneurysms

Abstract  Introduction: Sinus of Valsalva (SoV) aneurysms are rare (0.15% to 1.5% CPB cases) and five times more frequent in Asians. Usually congenital, SoV aneurysms arise from the right or noncoronary sinus, are associated with other cardiac defects, and are repaired primarily or with a patch. Acquired SoV aneuryms develop secondary to infection or trauma. Here, we describe our 32‐year experience with SoV aneurysm repair in a Western population. Methods: A retrospective review identified 22 patients who underwent SoV aneurysm repair between 1971 and 2003. Data is presented as mean ± standard error (median). Results: Dyspnea was the most common presenting symptom. Nineteen of 22 patients were ruptured at the time of operation; three were found incidentally. Fifteen patients had associated cardiac defects including ventricular septal defect (VSD) (6), aortic insufficiency (6), and coarctation (3). One patient, repaired primarily, required reoperation for recurrence. All other patients underwent patch repair. The operative survival was 95% (21/22). There were five known late deaths at 6.6 ± 2.3 (5.7) years post‐repair. Five and ten year survival rates were 84.9 ± 11% and 59.4 ± 17%, respectively. Conclusion: Observed differences in the sinus of origin, age at presentation, associated cardiac malformations, and mortality in our Western series versus previous Asian cohort studies likely reflect a racial disparity and higher prevalence of acquired versus congenital SoV aneurysms. We recommend a thorough search for a VSD in all cases and use of patch repair, regardless of size, to reduce risk of recurrence.

Impact of 24 h continuous hypothermic perfusion on heart preservation by assessment of oxidative stress.

Abstract:  Introduction:  Despite investigating numerous solutions, additives, and techniques over the last two decades, extending donor heart preservation beyond 4–6 h has not been achieved. Hypothermic heart preservation (HP) induces oxidative stress (OS) with reactive oxygen species (ROS) production, causing DNA cleavage and impairing repair. Quantification of cardiomyocyte concentrations of DNA damage by‐products (8‐oxoG) and mismatch repair enzymes (MYH, OGG‐1, MSH2) reflects the severity of OS. If increased repair enzyme production is insufficient to repair injury, cell death occurs and functional outcomes are impacted. We investigated continuous hypothermic perfusion (CHP), a new form of HP, and the mechanism of injury associated with hypothermic storage, by assessing functional outcome and OS after allotransplantation of canine hearts.

Pulmonary resection following lung transplantation

BACKGROUND The morbidity of lung transplantation is higher than other solid organ transplants. Little is known about the outcomes of patients who require pulmonary resection following lung transplantation. We reviewed our experience to evaluate and discern any variables affecting outcome of pulmonary resections performed following lung transplantation. METHODS A retrospective review of the lung transplant database was performed. Data are presented as mean +/- standard error (median). RESULTS A total of 136 lung transplants (80 single lung transplants [SLT], 55 bilateral lung transplants [BLT], and 3 heart-lung transplants [HLT]) were performed from August 1995 to February 2002. Twelve pulmonary resections, 7 lobectomies, and 5 wedge resections were performed on 11 patients. The indication for lobectomy was infection in 5 of 7 lobectomies (3 fungal, 2 bacterial), mass in 1 of 7, and infarction in 1 of 7. The indication for wedge resection was native lung hyperinflation in 4 of 5 wedge resections and mass in 1 of 5. The native lung was resected in 3 of 7 lobectomies and 4 of 5 wedge resections. An allograft lobectomy was performed following 1 SLT and 3 BLT and a wedge resection was performed after 1 SLT. The mean time to pulmonary resection was 12.4 +/- 3.9 (9.1) months. Survival postresection was 17.2 +/- 5.8 (8.3) months and 5 of 11 patients are still alive. There were no bronchial stump leaks following lobectomy. CONCLUSIONS Major pulmonary resections can safely be performed following lung transplant. We recommend early intervention to optimize outcomes.