What technical barriers exist for real-time fluoroscopic and video image overlay in robotic surgery?

BACKGROUND: A hypothetical advantage of the da Vinci console is its ability to integrate multiple visual data sources. Current platforms for augmented reality surgery fuse pre-operative radiographic studies but are limited with their ability to update with intra-operative imaging. The aim of our study was to evaluate the feasibility of real-time radiographic image overlay with current technology. METHODS: S-video composite output from a fluoroscopic C-arm was superimposed onto the video output of the da Vinci device. Image superimposition disparity measurements were evaluated in a bench model. The feasibility of robotic dissection assisted by real-time cholangiogram and intravenous pyelogram was evaluated. RESULTS: Image alignment resulted in a radiographic blind spot and image disparity with severely limited application in an in vivo model. CONCLUSIONS: External collisions of the robotic device and visual disparity in multiple planes negate the current implementation of fluoroscopic overlay and will require more elegant methods of computer-assisted registration.

Robotic intercostal nerve graft for reversal of thoracic sympathectomy: a large animal feasibility model.

BACKGROUND: A subset of patients who undergo video-assisted thoracoscopic sympathectomy for hyperhydrosis develop post-procedure compensatory sweating that is perceived as more debilitating than their initial complaints. We propose a novel treatment to reverse sympathectomy by implantation of an intercostal nerve graft using the da Vinci robot. METHODS: A robotic swine model was established using single-lung ventilation and four ports. The pleura was incised and a representative segment of sympathetic chain was transected. A nearby intercostal nerve was harvested and sutured to the sympathetic chain using four interrupted 10-0 nylon sutures on the epineurium. RESULTS: The intercostal nerve was an excellent size match and post-procedure necropsy yielded successful anastomoses without apparent complications. CONCLUSIONS: Robotic intercostal nerve grafting for reversal of thoracic sympathectomy is technically feasible. The robotic device allows the principles of neural microsurgery to be maintained and provides a minimally invasive option for reconstruction of the sympathetic chain.

Endovascular management of an aortobronchial fistula arising after resection of a primary aortic sarcoma: a case report.

The experience with the use of endovascular covered stents for aortic lesions has been growing. The early results of using endovascular covered stents for the exclusion of thoracic and infrarenal abdominal aortic aneurysms have been promising and are being investigated in multiple ongoing trials. Their usage for other aortic lesions has been reported sporadically, often as resourceful options in unusual and difficult clinical situations. The authors report a patient who had previously undergone resection of a thoracic aortic sarcoma and subsequently presented in extremis from an aortobronchial fistula. The evaluation and treatment of an aortic sarcoma and the successful urgent exclusion of an aortobronchial fistula through use of an endovascular covered stent are discussed.

Vascular clips have no significant effect on the cellular proliferation, intimal changes, or peak systolic velocity at anastomoses in rabbit vein grafts.

OBJECTIVE: This study compares vascular closure staples (VCSs) with conventional sutures in the rabbit carotid vein graft model to determine whether anastomotic technique affects cellular proliferation, blood velocity, or intimal changes when measured over a period of 3 months postoperatively. METHODS: Twenty-six New Zealand White rabbits weighing 3.0-3.2 kg underwent interposition of jugular vein grafts in left carotid arteries. Half of the animals had anastomoses performed with small VCSs (n = 13) and half had anastomoses performed with 8-O interrupted polypropylene suture. Animals were allowed to survive for 1 week (n = 4, VCS; n = 4, suture), 2 weeks (n = 4, VCS; n = 4, suture), and 3 months (n = 5, VCS; n = 5, suture). The peak systolic velocity (PSV) at the distal anastomosis was measured after completion of the graft and again at sacrifice in the 3-month survival groups. At sacrifice, sections were taken from the middle and distal end of the vein graft and the distal carotid artery. Vascular cell proliferation was measured using 5-bromo-2'-deoxyuridine labeling and intimal changes were measured using digitized microscopic images. RESULTS: All 26 grafts were open at the time of sacrifice. PSV at the distal clipped anastomosis was 40.52 cm/s (t = 0) and 34.3 cm/s (t = 3 months, P = 0.31). PSV at the distal sutured anastomosis was 38.30 cm/s (t = 0) and 39.23 cm/s (t = 3 months, P = 0.82). There was no difference between the two techniques at either t = 0 or t = 3 months (P = 0.51 and P = 0.31, respectively). Endothelial cell proliferation and smooth muscle cell proliferation at the anastomosis was highest during the 2 weeks after the procedure, then returned to baseline levels by 3 months. But there was no significant difference between the clipped and sutured groups with respect to vascular cell proliferation postoperatively. The intimal thickness changed significantly in the vein graft at the anastomosis for both the clipped and sutured groups (P = 0.0007 and P = 0.002). But there was no difference when the intimal changes for each technique were compared (P = 0.94). CONCLUSION: No differences were observed when peak systolic velocity, vascular cell proliferation, and intimal changes were compared between sutured and stapled anastomoses in rabbit vein interposition grafts over a period of 3 months after surgery.

Retinoic acid suppresses intimal hyperplasia and prevents vessel remodeling following arterial injury.

Vitamin A and its derivatives (retinoids) are capable of inhibiting vascular smooth muscle cell proliferation in vitro. The present study examines the effect of two retinoids, all-trans retinoic acid and 13-cis retinoic acid, on intimal hyperplasia following arterial injury. After receiving varying doses of all-trans retinoic acid or 13-cis retinoic acid, 78 male Sprague-Dawley rats underwent standard balloon catheter denudation of the left common carotid artery. Morphometric analysis and immunohistochemistry for proliferating cell nuclear antigen was performed at early and late time points. Intimal/medial ratios were reduced in a dose-dependent fashion for animals treated with all-trans retinoic acid (P = 0.001) and 13-cis retinoic acid (P = 0.004). Proliferating cell nuclear antigen labeling indices were reduced after treatment with all-trans retinoic acid and 13-cis retinoic acid at early time points post-injury. At a dose of 10 mg/kg, both all-trans retinoic acid and 13-cis retinoic acid inhibited vessel remodeling as measured by increases in luminal diameter (P < 0.05) and external elastic lamina (P < 0.05). Retinoids are an attractive clinical option for the treatment of restenosis following angioplasty and arterial surgery.

Aneurysms of the mid axillary artery in major league baseball pitchers--a report of two cases.

True aneurysms of the axillary artery and its branches are rarely identified. Our recent experience with successful repairs of symptomatic aneurysms of the axillary arteries at the origin of the circumflex humeral arteries in 2 major league baseball pitchers suggests a condition that may be more common than recognized previously. We report this unique experience with baseball pitchers to focus attention on a condition that should be considered in all athletes with hand pain, numbness, or signs of digital ischemia. In addition, a schedule of rehabilitation and the timing of an appropriate return to competition is presented.

Neuropsychometric changes in patients after carotid endarterectomy.

BACKGROUND AND PURPOSE: One hundred twelve patients undergoing elective carotid endarterectomy for symptomatic and asymptomatic carotid artery stenosis were enrolled in a prospective study to evaluate the incidence of change in postoperative cerebral function. METHODS: Patients were evaluated preoperatively and postoperatively before hospital discharge and at follow-up 1 and 5 months later with a battery of neuropsychometric tests. The results were analyzed by both event-rate and group-rate analyses. For event-rate analysis, change was defined as either a decline or improvement in postoperative neuropsychometric performance by 25% or more compared with a preoperative baseline. RESULTS: Approximately 80% of patients showed decline in one or more test scores, and 60% had one or more improved test scores at the first follow-up examination. The percentage of declined test scores decreased and the percentage of improved test scores increased with subsequent follow-up examinations. Group-rate analysis was similar for group performance on individual tests. However, a decline in performance was seen most commonly on verbal memory tests, and improved performance was seen most commonly on executive and motor tests. CONCLUSIONS: Neuropsychometric evaluation of patients undergoing carotid endarterectomy for significant carotid artery stenosis demonstrates both declines and improvements in neuropsychometric performance. The test changes that showed decreased performance may be associated with ischemia from global hypoperfusion or embolic phenomena, and the improvement seen may be related to increased cerebral blood flow from removal of stenosis.

Complementary surgical/interventional techniques for nonresective management of "inoperable" aneurysms: a second look.

Induced thrombosis ("nonresective" therapy) of aortic aneurysms by distal arterial ligation, coil/wire embolization, and extraanatomic bypass was devalued by anecdotal reports emerging during the mid-1980s. Nevertheless, we have recently found the technique to be life-saving in occasional cases and worth revisiting. Since 1990, standard aortic aneurysm repair has been performed in 231 patients (99.1% survival), endovascular aortic aneurysm repair in 6 patients (83.3% survival), and combined surgical/interventional "nonresective" repair of a variety of aneurysms in 10 patients (100% survival). Mean age of the group was 67.9 years. Repair was performed for aortoiliac aneurysms (4), common iliac aneurysms (3), internal iliac aneurysms (2), and a large proximal subclavian artery pseudoaneurysm (1). Four of the patients had been explored and declared to be "inoperable" (retroperitoneal fibrosis) prior to transfer to the Columbia-Presbyterian Medical Center. All patients survived. Aneurysm rupture has not occurred in any patient, but one patient with a presumably thrombosed subclavian pseudoaneurysm presented 26 months postcoil-induced thrombosis with progressive aneurysm enlargement due to incomplete aneurysm thrombosis and required repair using circulatory arrest. Eight of the patients remain alive (80%) at a mean follow-up of 40.3 months (range 14-88 months). Two patients died of malignancy (30 months) and cardiac disease (15 months). It is concluded that combined surgical/interventional techniques can be life-saving in the rare instances when conventional or endovascular aneurysm repair is not advisable but that complete aneurysm thrombosis is essential and occasionally difficult to achieve. Since small proximal portions of the aneurysm may remain patent and not be visualized on magnetic resonance imaging (MRI) or computed tomography (CT) scans, contrast angiographic documentation of complete aneurysm thrombosis is essential prior to hospital discharge and close follow-up is necessary to ascertain long-term adequacy of the repair. Incomplete thrombosis is suspected as a major factor in earlier reports of aneurysm rupture after seemingly successful nonresective therapy.