The Compress® transcutaneous implant for rehabilitation following limb amputation.

Amputation is an unfortunate outcome of a variety of orthopedic conditions. Many amputees can be functionally fitted with conventional suspension sockets. A substantial subset, however, fails this conventional treatment and is unable to function. In Europe, an alternative to socket-based prostheses has been available for 25 years. Patients there who are unable to functionally use socket-based prostheses have been offered the possibility for transcutaneous osseointegration. With this technology, the prosthetic limb can be rigidly attached to the residual bone, and the socket is eliminated, in many cases enabling improved function and patient satisfaction. In the United States, regulatory barriers have greatly limited the adoption and acceptance of transdermal osseointegration. The Compress® device was developed as an alternate means of fixation for massive endoprostheses, such as distal femoral replacements. A uniquely designed prosthesis is rigidly anchored to the end of the cortical bone and is then subjected to a large axial stress. The bone then grows avidly into the device, providing permanent osseointegration. We have recently adopted this device for transcutaneous use. These procedures have been performed in the United States on a custom regulatory basis. Results of this have been encouraging, and we are planning to begin a regulatory trial in the near future.

The fate of target visceral vessels after fenestrated endovascular aortic repair--general considerations and mid-term results.

OBJECTIVE: To carry out a retrospective analysis of the short and mid-term target vessels (TV) patency following fenestrated endovascular aortic repair (f-EVAR) of abdominal aneurysm (AAA). PATIENTS AND METHODS: Seventeen f-EVAR patients were analysed. The Zenith (Cook) fenestrated graft was used in all cases. Bare renal stents were used where good apposition existed between the stent graft and the aortic wall, and covered stents were chosen when this apposition appeared deficient. RESULTS: A total of 35 TV were treated: twenty with small fenestration and 15 with a scallop. Procedural technical success was achieved in 16 out of 17 patients. All TV were perfused at the completion angiography. Access to TV through small fenestrations was achieved in 18 out of 20 vessels. After a mean follow-up of 20.5 months no type I endoleaks were detected. No late complications were observed in any of the stented TV. One patient with perioperative bilateral renal artery occlusion remains on haemodialysis. One non-target renal artery, opposite a scallop was unintentionally covered. One kidney, initially perfused via a un-stented scallop fenestration, was atrophied 14 months post surgery. One patient died from heart failure. CONCLUSIONS: f-EVAR is a valid and safe treatment option. Our series and the world literature demonstrates a >90% TV preservation rate. Long-term intensive surveillance is required.

Value of diffusion-weighted MRI during carotid angioplasty and stenting.

INTRODUCTION: The incidence of neurological injury following carotid angioplasty and stenting is of great interest to those advocating it as an alternative to endarterectomy in the management of critical carotid stenosis. A significant inter-observer variation exists in determining the presence or absence of a neurological deficit following the procedure objective imaging would be advantageous. In this study, we sought to assess diffusion weighted MRI as a diagnostic tool in evaluating the incidence of neurological injury following carotid angioplasty and stenting (CAS). PATIENTS AND METHODS: The first 110 cases of CAS in our unit were included in this series. The procedure was abandoned in three patients. Patients underwent intracranial and extracranial MR angiography, together with diffusion-weighted MRI (DWI) prior to and following CAS and had a formal neurological assessment in the intensive care unit after the procedure. RESULTS: One hundred and ten Procedures were attempted in 98 patients. Twenty-eight percent were asymptomatic. Following CAS, 7.2% of patients had a positive neurological exam (two major strokes with one fatality) and 21% had positive DWI scans, equating to a sensitivity of 86% and a specificity of 85% for DWI in detecting cerebral infarction following CAS. The positive predictive value of the test was 0.3 and negative predictive value 0.99. The major stroke and death rate was 1.8%. While the use of a cerebral protection device appeared to significantly reduce the incidence of cerebral infarction (5% vs. 25%, p = 0.031) this may be a reflection of the learning curve encountered during the study. CONCLUSION: The incidence of subclinical DWI detected neurological injury was significantly higher than clinical neurological deficit following CAS. Conventional methods of neurological assessment of patients undergoing CAS may be too crude to detect subtle changes and more sensitive tests of cerebral function are required to establish whether these subclinical lesions are relevant.

Orthodeoxia--an uncommon presentation following bilateral thoracic sympathectomy.

We present a case of orthodeoxia (postural hypoxaemia) which resulted from a combination of lung collapse/consolidation and blunted hypoxic pulmonary vasoconstriction due to partial interruption of the sympathetic nerve supply to the lung by bilateral thoracic sympathectomy.

Use of the percutaneous vascular surgery device for closure of femoral access sites during endovascular aneurysm repair: lessons from our experience.

OBJECTIVES: to evaluate the results of our early experience with a percutaneous closure device for aortic aneurysm repair and to identify device related and patient related factors leading to procedure failure. METHODS: eighty-two percutaneous closures in forty-four patients was performed using the 10F Prostar XL Percutaneous Vascular Surgery device during the repair of 1 iliac, 1 thoracic and 42 abdominal aortic aneurysms. RESULTS: successful closure was achieved in 70 access sites (85%) with 12 sites requiring conversion to an open groin incision. The reasons for failure include difficult device introduction due to a tortuous iliac, deflection of needles due to previous scar, femoral artery occlusion and failure of the device to close the arteriotomy. There was one intraoperative death from retroperitoneal haemorrhage and another patient developed a pseudoaneurysm at the cannulation site. CONCLUSIONS: use of the percutaneous closure device requires very careful patient selection. Preoperative radiological assessment of the ilio-femoral vessels is vital to assess for cacification and tortuosity. High device failure rates can be expected from obese patients and those with scarred groins. When difficulty is encountered during the procedure, there should be a low threshold for conversion to an open groin incision. The device and the method of introduction can be further improved to address some of these issues.

Evaluation of patient selection guidelines for endoluminal AAA repair with the Zenith Stent-Graft: the Australasian experience.

PURPOSE: To review the patient selection guidelines for endovascular repair of abdominal aortic aneurysms (AAA) using the Zenith Endovascular Graft and establish an order of importance for each criterion. METHODS: The Zenith Endovascular Graft Research Database was interrogated for information on 238 patients (209 men; mean age 74.9 +/- 0.9 years, range 50-94) treated with a Zenith bifurcated graft from 1994 to 1998. The common complications of endoluminal AAA repair (endoleak, migration, graft occlusion, graft kinking, conversion, and deployment failure) were analyzed to determine any associations with selection criteria. RESULTS: By 1998, 69% of endograft patients did not meet the recommended guidelines; however, primary and secondary aneurysm exclusion rates were 87% and 94%, respectively. Over a median follow-up of 13.4 months (interquartile range 2.8-24.0), 38 (16%) patients developed 28 (74%) early and 10 (26%) late type-I endoleaks. The endoleak rate in necks < or = 10 mm long was 57% (8/14). Endoleak was associated with a neck contour change >3 mm (p = 0.003) and neck length <20 mm (p = 0.045). The risk of proximal endoleak was 4 times greater if at least one of the proximal neck guidelines was breached; combined guideline deviations of "contour change and large diameter" (p = 0.0004), "contour change and short length" (p = 0.006), "large diameter and short length" (p = 0.01), and "contour change and angle" (p = 0.03) also increased the risk of endoleak. Endograft migration was seen in 10 (4.2%) cases; only neck diameter >28 mm (p = 0.0024) was associated with this complication. CONCLUSIONS: Proximal neck contour, length, and diameter are the most important criteria in terms of endoleak development. Breaching the proximal neck length criterion resulted in a 4-fold increase in endoleak, and combined deviations from the guidelines multiplied the effect. Necks < or = 10 mm long are unsuitable for the standard Zenith graft.

Fenestration in endovascular grafts for aortic aneurysm repair: new horizons for preserving blood flow in branch vessels.

PURPOSE: To describe techniques for deploying fenestrated stent-grafts that use partial graft deployment and guided tracking of the fenestration to the arterial orifice. TECHNIQUE: Fenestrations have been added to custom-made tube grafts and commercially manufactured Zenith stent-graft systems to preserve perfusion of aortic side branches. Partial device deployment, orientation markers on the endograft, and intraoperative angiography enable maneuvering of the fenestration over the orifice of the target vessel with the aid of guiding catheters. Placement of a Palmaz stent overlapping the fenestration and vessel orifice secures the junction. Two variations of fenestration have preserved blood flow in renal arteries during endovascular repair of abdominal aortic aneurysms (AAAs); similar techniques have maintained flow to the celiac axis in a thoracic aortic aneurysm. CONCLUSIONS: Accurate placement of a fenestration over the orifice of a target vessel is feasible, but long-term maintenance of position is dependent on secure graft fixation. This capability brings us a step closer to overcoming the problem of inadequate necks in infra-renal AAAs, especially when the neck is foreshortened by asymmetry of the renal origins. It may also pave the way for the eventual replacement of the entire aorta with an endoluminal graft.

Hybrid open-endoluminal technique for repair of thoracoabdominal aneurysm involving the celiac axis.

PURPOSE: To describe a technique combining endoluminal and open approaches for the repair of thoracoabdominal aneurysms involving the celiac axis. CASE REPORT: Two patients with type I thoracoabdominal aneurysm and suboptimal cardiac reserve underwent transluminal stent-graft implantation. To achieve satisfactory distal seal, the caudal end of the endograft was circumscribed with a Dacron band that was sutured to the aorta and endograft through a midline incision. The patent celiac artery in both patients was ligated to stop retrograde filling of the aneurysm sac. The patients developed no problems perioperatively, and exclusion of the aneurysms was confirmed by follow-up imaging. Three years after endografting, both patients had excluded aneurysms without evidence of endoleak or device migration. CONCLUSIONS: This combined approach is another treatment option for thoracic aneurysms that have an anatomically suitable proximal attachment zone with a compromised distal neck.

Blood lipid profile in ischaemia reperfusion injury.

BACKGROUND: Lipid components are considered to play an important role in ischaemia reperfusion injury although the mechanism of their action remains unknown. Accumulation of lipid metabolites in ischaemic tissues is a consistent observation, but exactly how these lipids are cleared from the tissues by the circulating blood during reperfusion is still open to speculation. In the present study, levels of blood lipids (fatty acids, phospholipids, triglycerides, cholesterol, lysolecithin and lysolecithin platelet activating factor (lyso PAF)) and the enzyme phospholipase A2 were determined in an experimental animal model (dogs) of ischaemic reperfusion injury. METHODS: The injury was induced by 4 h of aortic clamping followed by 2 h of reperfusion (unclamping). Blood samples were collected before clamping and at predetermined time intervals (0, 15, 60 and 120 min) after the release of clamp. The lipid contents were analysed and compared with sham-treated control dogs. RESULTS: The results showed significantly elevated levels of triglycerides and phospholipase A2, during ischaemia and reperfusion in experimental animals indicating tissue damage in the ischaemic phase continuing into the reperfusion phase and the risk of systemic damage from these toxic substances. Total fatty acid content in the circulating blood showed decreasing trends during the same time interval, which suggested possible reduced clearance of accumulated fatty acids from the affected tissues. Serum cholesterol, phospholipids, lyso PAF and lysolecithin did not show any significant variation compared with control dogs. CONCLUSIONS: It is possible that the delayed clearance of fatty acids may be due to the presence of fatty acids binding proteins in the ischaemic tissue, which trap these fatty acids in the tissues during ischaemic reperfusion injury. The prolonged retention of the accumulated fatty acids in the tissues in association with elevated triglycerides and phospholipase A2 activity may contribute to ischaemia reperfusion injury.

The Perth HLB bifurcated endoluminal graft: a review of the experience and intermediate results.

Endoluminal grafting for abdominal aortic aneurysm based upon Dacron-coated Z stents was commenced in March 1993. A modular system for treatment of infrarenal aorto-iliac aneurysmal disease was developed in 1994. The experimental model, method of delivery, graft construction and initial results were reported. Since 1994, 108 bifurcated HLB (Perth) endografts for infrarenal aorto-iliac aneurysmal disease have been implemented. Initial technical success in deployment and exclusion of the aneurysm was achieved in 94 (87%) cases. Secondary endovascular procedures were performed in six cases and were successful in excluding the aneurysm. Ninety patients are alive currently. Twelve have died of co-morbid conditions. Six have died of aneurysmal disease, either from rupture or the result of treatment attempts. Fifteen early endoleaks (within 30 days) have been detected with three persisting. Four have sealed without further intervention, six after the secondary procedure and two patients have died. Conversion to open aneurysmal repair has been performed in five cases: three early and two late. Two of the early group but none of the late intervention group died. No graft infections have been detected to date. With increasing experience criteria for patient selection for endoluminal grafting and the type of graft to be inserted, have been developed. These criteria, lessons learnt and technical points of importance are discussed.

Endovascular conversion procedure for failed primary endovascular aortic stent-grafts.

Initial failure of successful deployment of endovascular aortic stent-grafts can be due to a variety of factors and frequently requires surgical intervention. We describe an endovascular technique for salvaging initially failed tubular aortic and bifurcated aortoiliac stent-grafts with reference to three cases.

Stability studies of amino acid substitutions at tyrosine 27 of the staphylococcal nuclease beta-barrel.

In order to help determine the extent to which side chain interactions within the staphylococcal nuclease beta-barrel affect its global stability, a full set of point mutants was generated for residue 27. Intrinsic tryptophan fluorescence was monitored during solvent denaturation with guanidine hydrochloride (GuHCl) and was used to calculate DeltaGH2O unfolding and m values for each mutant. In the wild type protein, residue 27 is a tyrosine which is at the first position of a type I' beta-turn, and which participates in both hydrophobic interactions and side chain to side chain hydrogen bonding. The hydrophobicity of the mutant residue was found to be the dominant factor in determining global protein stability within this series of nuclease mutants.

Successful embolization of persistent endoleak from a patent inferior mesenteric artery.

PURPOSE: To report the successful endovascular occlusion of a persistent endoleak owing to collateral perfusion in a 1-year-old bifurcated aortic endograft. METHODS AND RESULTS: An 81-year-old man underwent endovascular repair of a 5.5-cm abdominal aortic aneurysm (AAA) with a bifurcated stent-graft in 1995; collateral perfusion of the excluded aneurysm by retrograde filling of the patent inferior mesenteric artery (IMA) was noted postoperatively. At his 1-year follow-up, the mid-sac endoleak persisted on contrast-enhanced computed tomography. Using the superior mesenteric artery for access, the stump of the IMA was successfully embolized with glue. CONCLUSIONS: This case, which highlights the importance of documenting a patent IMA prior to AAA endografting, illustrates one option for the management of persistent collateral perfusion of endovascularly excluded aneurysms.

Comparison of transperitoneal and retroperitoneal approaches for infrarenal aortic surgery: early and late results.

The retroperitoneal approach to the infrarenal aorta was purported to have a shorter recovery and reduced degree of surgical stress than the transperitoneal approach. Hence, this study aimed to determine any advantages of one approach over the other. One hundred patients undergoing infrarenal aortic surgery between 1989 and 1992 were randomized to the transperitoneal or retroperitoneal approach; 64 operations were for aneurysms (32 transperitoneal, 32 retroperitoneal) and 36 for occlusive disease (18 transperitoneal, 18 retroperitoneal). Parameters monitored were operating time, cross-clamp time, blood loss, fluid requirement in first 24 h, analgesia requirements, gastrointestinal function, morbidity, mortality and length of stay in intensive care and hospital. A minimum 3-year follow-up was obtained to assess mortality and wound problems. Inter-group demographic data were comparable. There was no significant difference between the two approaches for: operating time 190 versus 202 min, P = 0.26); cross-clamp time (72 versus 81 min, P = 0.93); blood loss (1095 versus 1072 ml, P = 0.56); 24-hour fluid requirements (6900 versus 7000 ml, P = 0.45); analgesia requirements (60 versus 55 mg, P = 0.37), gastrointestinal function, morbidity (P = 0.75), mortality, and length of stay in intensive care (2 versus 2 days, P = 0.80) and hospital (10.5 versus 10 days, P = 0.76). In the long term there were significantly more wound problems (bulging, hernias and wound pain) in the retroperitoneal group. Long-term mortality was similar in both groups.

The Perth endoluminal bifurcated graft system--development and early experience.

The study aim was to develop a reliable endoluminal graft system that would enable the deployment of a bifurcated graft for infrarenal abdominal aortic aneurysms. A life-size plastic model was made of an abdominal aorta and iliac arteries, with a 50-mm infrarenal abdominal aortic aneurysm. This model was used to develop and test self-expanding graft systems, based on a barbed Gianturco stent and series of stainless-steel 'Z' stents within a woven Dacron graft. The bifurcated system developed involves a trouser graft with one long leg and one short. This graft-system is delivered through one femoral artery with deployment of the proximal aortic end infrarenally and the longer trouser leg within the ipsilateral common iliac artery. The short trouser leg is left hanging free within the distal end of the aneurysm cavity, just above the bifurcation. It is held open by a self-expanding stent and is cannulated from the contralateral femoral artery with a guide wire. A simple straight self-expanding stented graft is then deployed to extend this short trouser leg down into the common iliac artery, effectively creating an extension to the short leg. The graft system has been deployed in 21 patients with satisfactory exclusion of the aneurysm in 17 (81%). There has been one mortality and no conversion to open repair. All 17 aneurysms remain excluded at median follow-up of 30 (range 4-60) weeks. None of the four graft stents that leaked (two proximal and two distal) sealed spontaneously. Deployment of the uncovered Gianturco stent across the renal artery origins in 18 cases (85%) has not been associated with renal artery occlusion or deterioration in renal function at a median follow-up of 30 (range 4-60) weeks. The ability to deploy a bifurcated system increases the potential for endoluminal treatment of abdominal aortic aneurysm.

Benign and malignant muscle tumors in the hand and forearm.

Although soft tissue tumors are common in the hand and forearm, muscle tumors are relatively rare. Although presentation may be similar between benign and malignant muscle tumors, prognosis can differ tremendously. Accurate and early diagnosis is critical to minimize morbidity.

Trends in the practice of arterial surgery in Western Australia.

An overview of arterial surgery in Western Australia and the Department of Vascular Surgery at Royal Perth Hospital was undertaken for the ten year period from 1983 to 1992. The annual number of arterial procedures increased 116% from 937 to 2027 and lower limb amputations increased 44% from 335 to 483. Five arterial procedures were examined in detail. There was a marked increase in carotid endarterectomy and angioplasty, a moderate increase in aortic aneurysm repair and a small increase in aortofemoral and femoropopliteal bypass surgery. The major amputation rate was not influenced by bypass surgery. It rose from 113 per million population in 1983 to a peak of 148 in 1986, and then fell to 113 per million population in 1992. From June 1982 to June 1992 the population of Western Australia rose 24%, from 1.34 to 1.66 million (and for persons 60 years and over, rose 38% from 0.16 to 0.23 million). At Royal Perth Hospital similar trends were observed. Mean duration of operation for all vascular procedures and for the individual procedures of carotid endarterectomy, angioplasty, aortic aneurysm repair and aortofemoral and femoropopliteal bypass remained unchanged. Average length of stay decreased for carotid endarterectomy (29%) and angioplasty (74%), but remained unchanged for aortic aneurysm repair and aortofemoral and femoropopliteal bypass.

Intraobserver and interobserver variability of the amniotic fluid index.

OBJECTIVE: We assessed intraobserver and interobserver variations in the performance of the amniotic fluid index. STUDY DESIGN: A total of 34 women in the third trimester with intact membranes were examined twice by each of three examiners. The amniotic fluid index was measured once by each of the three examiners in order, then repeated by each examiner in the same order. Numeric displays on the video terminal screen were covered so that the examiners were blinded to actual measurement values. Results were recorded on hard copy for later data analysis. A senior investigator supervised all examinations to monitor consistency of technique. RESULTS: Overall, the coefficient of variation for amniotic fluid index measurements varied from 10.8% within examiners to 15.4% between examiners. Both between and within variation of absolute differences increased as the amniotic fluid index value increased, while the percent difference decreased. Simply repeating the test by the same examiner will decrease the coefficient of variation significantly. CONCLUSION: Although intraobserver and interobserver variability cannot be eliminated, its impact can be minimized by use of the same examiner for serial studies.