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Biomedical subjects

W Sandmann

Publications and source records attributed to W Sandmann.

At least 37 records · Page 2Linked to original sources
PubMed1996

The risk of ischemic spinal cord injury in patients undergoing graft replacement for thoracoabdominal aortic aneurysms.

PURPOSE: We developed a monitoring system to detect spinal cord ischemia during aortic cross-clamping (AXC). This system was used to prospectively determine in which patients ischemia occurs, in which patients reimplantation of intercostal arteries is unnecessary or mandatory, and when reperfusion of intercostal arteries (ICAs) is urgent. METHODS: Two hundred sixty patients underwent thoracoabdominal aortic aneurysm (TAA) repair with simple AXC. In 167 patients, two electrocatheters were placed before the onset of anaesthesia at level L1/L2 (stimulation) and level T5/T6 (recording) within the epidural space. During surgery, spinal cord function was monitored by recording spinal somatosensory evoked potentials (sSSEP). According to the extent of aortic replacement, most patients were expected to have a high risk of paraplegia. RESULTS: In group A (59 patients), sSSEP remained normal throughout surgery, and in 54 of these patients ICAs were not reattached outside the proximal aortic anastomosis. In the other five patients ICAs were reimplanted separately because of possible anatomic relation to spinal cord blood supply. No patient in group A had postoperative neurologic deficit. In group B (54 patients) sSSEP remained normal until 15 minutes after AXC but were impaired thereafter. Nineteen patients had early reimplantation of ICAs. Of the 19, three had paraparesis and two had paraplegia. Neurologic deficit developed in the patients without early reimplantation of ICAs. In four patients separate reimplantation of ICAs was performed late in the procedure because of incomplete sSSEP recovery. Subsequently, the sSSEP returned to normal and only one of the four patients had mild paraparesis. The total rate of neurologic deficits in this group was 13% (paraplegia, 3.5%; paraparesis, 9.5%). All 54 patients in group C showed rapid loss of sSSEP within 15 minutes of AXC. In 28 patients ICAs were reimplanted only within the proximal anastomosis. Twenty-one of these patients showed prompt signal recovery after blood-flow release into the reimplanted ICAs, and none had neurologic deficit. Seven patients had no or very late and incomplete sSSEP recovery. Of the seven, three had paraplegia and four had paraparesis. In 26 patients ICAs were reimplanted separately to the proximal anastomosis. This was done early during the procedure in 17 patients, of whom 13 had full recovery of sSSEP and normal neurologic status. Four patients had incomplete or no recurrence of sSSEP, followed by paraplegia in one and paraparesis in three. In nine patients ICAs were reimplanted after the aortic replacement had been completed because of sSSEP recovery was not satisfactory. In all patients in this subgroup sSSEP returned to normal. Six patients had a normal neurologic status and three had mild paraparesis. The total neurologic complication rate in group C was 26% (paraplegia, 7.5%; paraparesis, 18.5%). CONCLUSION: The risk of ischemic spinal cord injury during replacement for TAA can be assessed continuously by monitoring the sSSEP directly from the spinal cord. Patients without sSSEP changes during aortic reconstruction do not require ICA reattachment and will not have neurologic deficit. Patients who lose sSSEP after AXC are at risk for paraplegia. Patients with impairment or loss of sSSEP >15 minutes after AXC have some collateral vessels, and must have ICAs reimplanted only if sSSEP do not return within normal recovery time after blood-flow release into the proximal anastomosis. Loss of sSSEP within 15 minutes of AXC shows poor collateralization and mandates early restoration of spinal cord blood supply. If the surgeon can achieve the return of sSSEP to normal by subsequent separate reimplantation of ICAS, paraplegia will not occur and paraparesis will be rare and mild. Spinal cord monitoring is a valuable guide to detect whether the spinal cord is at risk and to take measures against par

Anastomosis, Surgical↗
PubMed1996

Pseudo- and segmental occlusion of the internal carotid artery: a new classification, surgical treatment and results.

OBJECTIVES: Occluded internal carotid arteries imply a high risk of ischaemic complications, but an "occluded" carotid artery is not always totally occluded. Pseudo- and segmental occlusions can be detected angiographically, and increasingly non-invasively, and include a variety of morphologic findings. METHODS AND MATERIALS: 128 patients with pseudo- or segmental occlusion were treated in a 13 year period. Three different types of pseudo- or segmental occlusion were identified. In most cases a subtotal stenosis (near-occlusion) at the carotid bifurcation is the underlying lesion (type I). In approximately 35% the internal carotid artery is totally occluded at the bifurcation, but collaterals prevent downstream occlusion (type II), or retrograde flow from the circle of Willis and ophthalmic artery preserves a patent petrous part and siphon (type III). RESULTS: In 79% patency of the arteries could be restored. Three patients (2.3%) died perioperatively, nine (7%) developed ischaemic stroke (7 ipsilateral, 2 contralateral), one intracerebral haemorrhage. The combined stroke-mortality rate was 8.6%. During follow-up (41 +/- 29.9 months) four patients (4.5%) experienced a stroke (3 ipsilateral, 1 contralateral), one an intracranial (1.1%) haemorrhage and six transient ischaemic attacks (6.7%). The annual ipsilateral stroke rate was 0.9%, the cumulative patency rate of the entire series 78% after 73 months. CONCLUSIONS: Although the surgical management carries an increased risk of complications (stroke, transient ischaemic attacks) compared to conventional carotid endarterectomy it is likely that the stroke risk can be reduced at least for symptomatic patients. Symptomatic internal carotid artery occlusion diagnosed non-invasively should be confirmed angiographically to exclude pseudo- or segmental occlusion.

Adult↗
PubMed1996

Small, oral dose of clonidine reduces the incidence of intraoperative myocardial ischemia in patients having vascular surgery.

BACKGROUND: Most new perioperative myocardial ischemic episodes occur in the absence of hypertension or tachycardia. The ability of alpha 2-adrenoceptor agonists to inhibit central sympathetic outflow may benefit patients with coronary artery disease by increasing the myocardial oxygen supply and -demand ratio. METHODS: A randomized double-blind study design was used in 297 patients scheduled to have elective vascular surgical procedures to evaluate the effects of 2 micrograms/kg-1 oral clonidine (n = 145) or placebo (n = 152) on the incidence of perioperative myocardial ischemic episodes, myocardial infarction, and cardiac death. Continuous real-time S-T segment trend analysis (lead II and V5) was performed during anesthesia and surgery and correlated with arterial blood pressure and heart rate before and during ischemic events. Dose requirements for vasoactive and antiischemic drugs to control blood pressure and heart rate as well as episodes of myocardial ischemia (i.e., catecholamines, beta-adrenoceptor antagonists, nitrates, and systemic vasodilators) and fluid volume load were recorded. RESULTS: Administration of clonidine reduced the incidence of perioperative myocardial ischemic episodes from 39% (59 of 152) to 24% (35 of 145) (P < 0.01). Hemodynamic patterns, percentage of ischemic time, and the number of ischemic episodes per patient did not differ. Nonfatal myocardial infarction developed after operation in four patients receiving placebo compared with none receiving clonidine (day 2 to 21; P = 0.07). The incidence of fatal cardiac events (1 vs. 2) was not different. Dose requirements for vasoactive and antiischemic drugs did not differ between the groups, but the amount of presurgical fluid volume was slightly greater in patients receiving clonidine (951 +/- 388 vs. 867 +/- 381 ml; P < 0.03). CONCLUSION: A small oral dose of clonidine, given prophylactically, can reduce the incidence of perioperative myocardial ischemic episodes without affecting hemodynamic stability in patients with suspected or documented coronary artery disease.

Administration, Oral↗
PubMed1996

[Infection of a vascular prosthesis--a retrospective analysis of 99 cases].

From January 1, 1980 to December 31, 1992, 7970 vascular prostheses have been implanted at the Department for Vascular Surgery and Kidney Transplantation of the University of Düsseldorf. In the same period of time, 99 patients had to be reoperated for (type Szilagyi III [14]) graft infection (1,2%), out of which 70 patients have had their previous operation in our institution (0,9%). The infection became apparent within 30 days in 14 cases, within one year in 54 cases, and in 31 cases within a maximum of 8 years postoperatively. Localisation of the infection was the groin in 70 patients, abdominal aortic prostheses were involved in 16, crural or extraanatomic prostheses in 13 cases. Treatment consisted in most cases of axillofemoral bypass (n = 23) and obturator-bypass (n = 21). In-situ-implantation of vascular prostheses was performed in 8 cases, 4 of these prostheses were intraoperatively soaked with an antibiotic. 47 patients had various reconstructions, such as cross-over bypasses, atypical reconstructions or local treatment. Postoperatively 27 amputations were necessary. 30-days mortality rate was 12%. At the end of the follow-up (May 1994) we found a 54% total mortality rate (mean follow-up: 4.6 +/- 4.59 years). Main cause of death in the first year was sepsis. In only 67% of patients discharged from hospital, the peripheral arterial conditions were described as "good" by angiography, ankle-brachial index or clinical examination. We conclude, that vascular graft sepsis threatens the patient in the early phase because of limb loss or death, and during the first year after the operation for the sequelae of sepsis or recurrence. Revascularisation with antibiotic-soaked grafts in a limited number of cases showed good results in preserving limbs and lives of our patients. Future experience will show, whether antibiotic-soaked grafts should be used more generously in vascular surgery.

Adult↗
PubMed1996

[Intraoperative quality control after vascular surgery reconstruction of kidney and visceral arteries: personal experiences with intraoperative angioscopy].

Angioscopy was applied as a way of intra-operative assessment after surgical reconstruction of renal and visceral arteries in 15 patients. Angioscopy resulted in relevant findings, which in part, demanded immediate intra-operative consequences. Angioscopy turned out to be a sensitive way of surveillance, the findings were easy to interpret.

Angioscopy↗
PubMed1996

[Vascular surgery operations in tumor diseases].

In a retrospective analysis covering 10 years, we examined 53 patients with malignant tumors, who had undergone 74 vascular reconstructive operations. The rate of all complications was 40%. Thirty-two patients died within a period of 3.1 years because their tumor progression; the survival rate after an average of 6.9 years was 65.6%.

Aortic Aneurysm, Abdominal↗
PubMed1996

[Abdominal aortic aneurysm--is surgical therapy in over 80-year-old patients justified?].

Abdominal aortic aneurysm repair in patients of 80 years and older has been performed in 51 patients over a period of ten years from 1985 to 1995; one-third of these patients underwent emergency operation for ruptures. The low mortality rate of 3.2% for the elective repair and the good long time survival expectancy, which does not differ very much from the life expectancy of the general population over 80 years, justify the elective abdominal aortic aneurysm repair in octogenarians. The high mortality rate of 69.2% in the case of rupture emphasizes the importance of elective aneurysm repair.

Aged↗
PubMed1995

Surgical treatment of septic deep venous thrombosis.

BACKGROUND: Septic deep venous thrombosis (SDVT) is an uncommon but occasionally lethal disease caused by systemic complications. In most cases reported in the literature SDVT is caused by intravenous drug abuse or transvenous catheter lines. Conservative management with antibiotic drugs and systemic anticoagulation is usually successful, and the surgical approach is regarded as not indicated or unnecessary. Occasionally, however, conservative management fails, thrombosis progresses, and septic embolism develops. METHODS: In a 7-year period five patients (three male and two female; mean age, 21.2 years), three with severe systemic complications of SDVT (femoropopliteal, 1; iliofemoral, 1; iliofemoral+vena cava, 3), were treated by venous thrombectomy in addition to intravenous antibiotic administration. Simultaneous transabdominal caval thrombectomy was performed twice. RESULTS: Two patients suffered from respiratory failure caused by previous septic embolization. One patient had experienced multiorgan failure before thrombectomy was performed. Intensive care was necessary for all patients (mean, 28 days). All patients survived. CONCLUSIONS: In complicated cases of SDVT without improvement or even impairment after conservative management, venous thrombectomy is a lifesaving treatment.

Adolescent↗
PubMed1995

[Surgical treatment of thoraco-abdominal aneurysm. Indications and results].

Aortic replacement for thoraco-abdominal aneurysms remains a major challenge in vascular surgery. Related symptoms, maximal diameter > 6 cm, progression, aneurysm sac containing none or excentric thrombi and uncontrollable hypertension are factors in favour of surgery, if the general condition of the patient allows the operation. Patients with aneurysms < 5 cm maximal diameter, tube-size aneurysms, heavy calcification of the aortic wall, concentric thrombi within the aneurysmal sac and significant cardiopulmonary risks should be treated conservatively. Patients in good general condition with aneurysms around 5 cm maximal diameter should be controlled by computed tomography in 6 to 12 months intervals and in the case of progression surgery can be recommended despite missing symptoms. Crawford developed the 'graft-inclusion-technique', which combines the 'ingraft'-technique with reattachment of renal, visceral and segmental arteries. The 'clamp and repair' principle is used in patients with sufficient cardiac function. Otherwise shunt or left sided heart bypass are used to reduce cardiac afterload. According to the literature local cooling (flush perfusion), cytoprotective drugs and numerous methods to maintain or ameliorate distal aortic perfusion during clamping ischemia have been used in patients successfully for prevention of ischemic spinal complications. In physiological settings these methods may prove valuable, but under pathophysiological conditions of TAAA-repair one must doubt the efficacy, because the individual risk is difficult to assess. In our hands flush perfusion and cooling of the kidneys proved to be helpful. In animal experiments we have shown prolongation of ischemia tolerance time using eicosanoides to protect the kidneys and the spinal cord. If shunt or left-sided heart bypass can protect the spinal cord during clamping, is unknown, because the risk of paraplegia in the individual patient can be known only, if the function of the spinal cord is monitored. We have developed a spinal neuromonitoring system and found, that only one third of all TAAA-patients is at high risk to develop paraplegia during aortic clamping. The surgeon is guided by continuous recording of spinal evoked somatosensory potentials and can adapt the operative technique by early reimplantation and eventually subsequent separate reimplantation of segmental arteries supplying blood to the spinal cord, in order to reduce spinal ischemia time. Our results in 260 TAAA-patients are presented. In a high-risk population of patients with aneurysms type I-III (Crawford's classification) it was possible, to reduce the paraplegia rate from 7 to 3.5%, the risk of paraparesis from 15 to 6%, while the operative mortality was only reduced from 19 to 10%.

Adult↗
PubMed1995

[Angioscopy as intraoperative outcome control after reconstructive surgery of the renal arteries: presentation of a new method].

Main reasons for obstruction of renal arteries are atherosclerosis and fibromuscular dysplasia. In our clinic transaortic renal endarterectomy and interposition of a vein segment are preferred for arterial reconstruction. The surveillance of the distal intimal ridge after blind transaortic endarterectomy is still an unsolved problem, and the distal anastomosis of a vein graft must be checked, as it is performed under difficult conditions, if the suture is done in situ. We introduce angioscopy as a means of intraoperative surveillance.

Anastomosis, Surgical↗
PubMed1995

[Open indications for endovascular surgery].

Endovascular techniques are becoming a part of minimally invasive surgery. The AIM is either preservation or reconstruction of the vascular lumen without the risk involved in conventional reconstructive procedures. The therapeutic success is often only palliative and not durable, because only the local cause of the disease is excluded and not removed definitively. Despite improvement in the technical equipment the indication for endovascular surgical treatment remains questionable and is the subject of experimental vascular research. Like other innovative procedures, the place for endovascular procedures will emerge in relation to the individual patient risk patient concerning age, concomitant diseases and cardiorespiratory conditions. In comparison to conventional reconstructive procedures endovascular techniques are being strongly pushed by specialists and industry because the risks of treatment are believed to be significantly lower. However, the risks of conventional vascular reconstruction are often overestimated and, as a rule, the failure rate in endovascular reconstructive surgery is often underestimated.

Angioplasty, Balloon↗
PubMed1995

[Surgical therapy of occlusions of the brachiocephalic trunk: long-term follow-up after transthoracic reconstruction].

Hemodynamically relevant lesions of the innominate artery can be treated either by extraanatomic bypass or by intrathoracic repair. 32 patients were retrospectively evaluated after ascending aorta to innominate artery interposition graft. In all except 6 cases additional bypass-procedures to extracranial vessels were necessary for complete revascularisation. The patency rate was 100% after a mean follow up period of 871 days. Only one patient suffered from a perioperative stroke with upper extremity paresis which resolved after 2 weeks. There were 3 wound complications which required reoperation. In conclusion we believe that direct intrathoracic repair for innominate artery occlusion can be recommended as a treatment of choice with a high long-term patency rate.

Adult↗
PubMed1994

[Chronic mesenteric ischemia].

Thirty-four patients (twelve men, 22 women, mean age 53[16-71] years) with chronic mesenteric ischaemia were operated upon between 1979 and 1992. The most frequent symptom was loss of weight (50%) and postprandial pain (44%). The mean interval between onset of symptoms and diagnosis was 35 months. Angiography revealed disease of the coeliac trunk (CT) or the superior mesenteric artery (SMA) in 16 patients, of only the SMA in ten, and of only the CT in eight. Revascularisation was obtained with an autologous vein graft in 21 patients (on the TC in 12, AMS in nine), while transaortic endarterectomy was performed in 15 (on the CT in seven, the AMS in nine). There was one perioperative death. 20 patients were symptom-free 1-126 months after the operation, while five still had residual symptoms even though improved in three. Seven patients had a recurrence of symptoms, three immediately after operation and four after an initial symptom-free period. These results show that freedom from symptoms can be achieved even in advanced stages of chronic mesenteric ischaemia by reconstructive surgery of the intestinal and visceral arteries. However, residual symptoms that are possibly not of a vascular nature may persist after successful vascular reconstruction. Patients with recurrent obstruction may become symptom-free by repeat surgery even many years later.

Adolescent↗
PubMed1994

Complications following caval interruption.

Caval interruption is widely regarded as the treatment of choice for the prevention of recurrent pulmonary embolism (PE). The safety, ease of insertion and "convenience" of the devices are the main arguments for filter placement. Today many filters are placed for prophylactic reasons, sometimes without an established diagnosis of pulmonary embolism or underlying deep venous thrombosis. Early and late complications have been published but the rate is reported to be low, although only limited numbers of patients have been followed. In an 18-year period 11 patients with problems following caval interruption were treated, 10 with acute complications, one with chronic caval occlusion. Six were treated conservatively, five underwent venous thrombectomy and a.v.-fistula. The device was removed in four. During the same period only three permanent filters were placed in our hospital (two with complications). Caval interruption is useful in selected high-risk patients and is the least invasive but not necessarily the best treatment. Provided stringent criteria are applied, the early and late complications can be accepted in order to prevent sudden death in patients with threatening massive PE. Extended or more liberal indications for caval interruption are neither necessary nor justified.

Adult↗
PubMed1994

[Fresh homologous arterial transplant as aorto-iliac-femoral vascular replacement in prosthesis infection].

A patient with late graft infection in the groin following aorto-bifemoral-Dacron-bypass and recurrent infection of extra-anatomic bypasses is presented. Despite the evidence or graft infection (by preoperative imaging studies and intraoperative perigraft purulence) cultures did not identify the infective organism. Retrospectively a graft infection with Staphylococcus epidermidis is supposed as the most likely cause. A graft replacement with freshly harvested, not cryopreserved arterial homograft was performed. The perfusion of the extremities was excellent, the wounds healed perfectly. In special indications freshly harvested cadaveric arterial homografts are an acceptable substitute for infected aorto-femoral grafts.

Aorta, Abdominal↗
PubMed1994

[Subclavian-carotid transposition--experience in the treatment of arteriosclerotic lesions of the carotid artery near its origin].

Symptomatic atherosclerotic lesions of the subclavian artery are rare. A special treatment is necessary and consists today of various extrathoracic bypass procedures or a subclavian-carotid-transposition. The latter is our preferred kind of therapy. 116 patients (57 female, 59 male, mean age 59.1 years, 116 operations) underwent subclavian-carotid-transposition for symptomatic subclavian artery lesion of the first segment. In 33.6% a thrombendarterectomy of the ipsilateral carotid bifurcation and in 19% an open or eversion thrombendarterectomy of the second segment of the subclavian artery and/or the vertebral artery had to be performed. 3 patients (2.6%) died perioperatively (myocardial infarction 2, cerebral infarction 1). In 3 out of 4 early postop, thrombosed transpositions patency was restored successfully. 70 patients (74.5% of the patients alive) were followed for in the mean 58.6 +/- 41.5 months. The transposition was found to be patent in 67 (95.7%) patients, a mild stenosis presented 2, an occlusion 1 (occluded perioperatively). The cumulative patency rate (126 months) was 95%. Subclavian-carotid transposition is in contrast to bypass procedures a more difficile treatment for symptomatic subclavian lesions with various advantages. Besides an orthograde inflow to subclavian and vertebral artery and the construction of simply one anastomosis with wall segments of identical compliance the main advantage is the avoidance of any autogenous or artificial bypass material. Excellent long-term results underline that this therapy is the more elegant and better concept treating subclavian artery lesions of the first segment.

Adult↗