Distal Attachment Research Articles

Efficacy of a Distal Attachment in Endoscopic Resection of Colorectal Polyps Situated behind Semilunar Folds

It is difficult, dangerous, and time consuming to resect colorectal polyps situated behind the semilunar folds. The aim of this study was to examine the efficacy of a distal attachment in the endoscopic resection of these polyps. The study group consisted of 11 patients, each with a colorectal polyp situated behind a semilunar fold, and of which the base was invisible without the use of a distal attachment. With the attachment fitted to the distal end of the endoscope, we pressed the semilunar fold situated at the anal side of the polyp so that the polyp, including its base, could be brought within the visual field. Maintaing the optimal position, we snared, ligated, and resected all polyps by electrocautery. The polyps were of sessile type in eight patients and pendunculated type in three, with a diameter ranging from 7 to 18 mm (mean 11 mm). Although the base of the polyp was invisible under conventional observation, pressing the fold brought good visualization. The optimal position for snaring the polyp was secured by fine endoscopic adjustment, and the polyps were easily resected in all patients. We conclude that the distal attachment is a simple but very valuable tool in the endoscopic resection of colorectal polyps situated behind the semilunar folds, and recommend its routine use in both diagnostic and therapeutic colonoscopy.

MUSCLE ARCHITECTURE OF THE THORACIC PORTIONS OF THE LONGISSIMUS AND ILIOCOSTALIS MUSCLES IN THE HUMAN

The purpose of this study was to investigate previously undescribed muscle architecture of selected sections of the longissimus and iliocostalis muscles in the human. Five human cadavers (3 females and 2 males, age range 55–74) were available for dissection. The longissimus and iliocostalis were dissected and analyzed. The following muscle architectural properties were measured: muscle mass, muscle length (Lm), fiber length (Lf), and pennation angle (PA). Measures of the two muscles in whole revealed that the longissimus has greater muscle mass than the iliocostalis. For example, the mean value for the muscle mass of the longissimus was 170.4 ± 38.2 g and that of the iliocostalis was 92.0 ± 36.8 g. The mean muscle length of the longissimus (44.04 ± 10.2 mm) was longer than the iliocostalis (37.2 ± 4.4 mm). In the analysis between individual segments of the longissimus and iliocostalis, there was a wide variety in architectural measures, with some overall trends noted. For example, in the longissimus muscle, the muscle mass was generally greater at the lower transverse process attachments of the thoracic vertebra 12 to 9 and then decreased at the higher thoracic attachments at the thoracic vertebra 4 to 1. There was also a similar trend for the Lf of the longissimus, although this was not as strong. The muscle mass of the iliocostalis muscle showed a similar trend from its distal attachment to rib 12 demonstrating greater muscle mass (16.6 ± 6.3 g) than the segmental attachment to rib 1 (4.5 ± 2.6 g). The Lf of the iliocostalis was much more variable from its distal rib 12 attachment to its proximal rib 1 attachment. In conclusion, this is the first descriptive study to examine the architectural properties of the thoracic portions of the longissimus and iliocostalis muscles in the human. Some trends were noted between the individual segmental attachments within each thoracic portion of the muscle, but it was also noted that there is a wide variety between the individual segments as well. Further investigation is needed to establish if there are specific trends within the thoracic portions of the longissimus and iliocostalis.

Anatomy and function of the subdeltoid bursa.

An anatomical study was undertaken on 40 non-embalmed normal cadaver shoulders to determine the attachments, boundaries and macroscopic nerve supply of the subdeltoid bursa. Two areas of attachment were observed, one (proximal and superficial) along the free border of the coracoacromial ligament and adjacent deep surface of deltoid, the other (distal and deep) to the humerus distal to the supraspinatus tendon: there were no posterior or anterior attachments. In addition, two blind pouches were observed, one proximal under the coracoacromial ligament and the other beyond the distal attachment. The continuity observed between the lateral border of the coracoacromial ligament and the subdeltoid bursa provides a smooth surface, thereby casting doubt on the aggressive action of the ligament on the rotator cuff.

Endoleaks following endovascular repair of abdominal aortic aneurysm: The predictive value of preoperative anatomic factors—a review of 100 cases

Objective: The failure to maintain a secure exclusion of aortic aneurysms with intraluminally placed grafts has been termed endoleak. We performed a retrospective review of our first 100 transluminally repaired abdominal aortic aneurysms (AAAs) in an effort to identify preoperative factors that could predict which patients would have endoleaks. Methods: Between February 1993 and September 1998, 100 infrarenal aneurysms were treated with tube (39), bifurcated (45), and aortoiliac grafts (16). Endoleaks (early and late) developed in 34 patients. Preoperative computed tomography scans and angiograms for all patients were individually inspected by a single reviewer. Aortic characteristics analyzed included number of patent lumbar arteries, presence of a patent inferior mesenteric artery (IMA), calcification and thrombus at proximal and distal attachment sites, proximal aortic angulation, and graft-vessel size discrepancy at proximal and distal attachment sites. The prevalence of the preoperative factors was compared among patients with and without endoleaks. Results: Endoleaks developed in 44% of tube, 33% of bifurcated, and 47% of aortoiliac grafts (P =.51). Correlation between total number of patent lumbar arteries, presence of a patent IMA, and endoleaks was not significant (P =.44,.95). Calcification at either proximal or distal attachment site did not increase the risk of endoleaks (P =.50,.62). The presence of thrombus at the attachment site (proximally or distally) also failed to increase endoleak rates (P =.12,.78). Degree of proximal aortic angulation did not differ between groups (P =.39). Size discrepancies between graft and aorta or iliac vessels at proximal or distal sites did not significantly differ (P >.54, >.13). Subgroup analysis of endoleaks with different tube types also failed to demonstrate significant differences among the three graft types (P >.05). Conclusion: Endoleaks develop in a significant number of endovascularly repaired AAAs. We were unable to demonstrate a statistically significant association with anatomic characteristics thought to predispose to the development of endoleaks. We find no predictive value associated with these anatomic factors. (J Vasc Surg 2001;33:739-44.)

Effect of contact stress in bones of the distal interphalangeal joint on microscopic changes in articular cartilage and ligaments.

To examine articular cartilage of the distal interphalangeal (DIP) joint and distal sesamoidean impar ligament (DSIL) as well as the deep digital flexor tendon (DDFT) for adaptive responses to contact stress. Specimens from 21 horses. Pressure-sensitive film was inserted between articular surfaces of the DIP joint. The digit was subjected to a load. Finite element models (FEM) were developed from the data. The navicular bone, distal phalanx, and distal attachments of the DSIL and DDFT were examined histologically. Analysis of pressure-sensitive film revealed significant increases in contact area and contact load at dorsiflexion in the joints between the distal phalanx and navicular bone and between the middle phalanx and navicular bone. The FEM results revealed compressive and shear stresses. Histologic evaluation revealed loss of proteoglycans in articular cartilage from older horses (7 to 27 years old). Tidemark advancement (up to 14 tidemarks) was observed in articular cartilage between the distal phalanx and navicular bone in older clinically normal horses. In 2 horses with navicular syndrome, more tidemarks were evident. Clinically normal horses had a progressive increase in proteoglycans in the DSIL and DDFT. Load on the navicular bone and associated joints was highest during dorsiflexion. This increased load may be responsible for microscopic changes of tidemark advancement and proteoglycan depletion in the articular cartilage and of proteoglycan production in the DSIL and DDFT Such microscopic changes may represent adaptive responses to stresses that may progress and contribute to lameness.

13 Years’ Experience with the Combined Hormonal Therapy of Cryptorchidism

Purpose: We analyze the results of the combined treatment with luteinizing hormone releasing hormone (LH-RH) and human chorionic gonadotropin (HCG) of a large series of patients with cryptorchidism. Materials and Methods: Between 1987 and 1999 and after strict differentiation between cryptorchid, retractile and gliding testes, 2,467 boys with 2,962 cryptorchid-gliding testes were treated with the combined hormonal therapy. LH-RH was administrated as a nasal spray at a dosage of 1.2 µg daily for a period of 4 weeks. HCG was injected intramuscularly, 5 times at 2-day intervals at a dosage adjusted according to the age. Results: In the prospective study 2,476 boys with 2,962 cryptorchid testes were hormonally treated. Of the 2,962 evaluated cases 1,200 (40.52%) have been treated surgically after the hormone therapy. In 1,762 cases, 59.48% of cryptorchid testes were in the scrotum after combined hormone treatment. Conclusions: Treatment with LH-RH and HCG induced the descent of the testes to a normal scrotal position of boys with cryptorchidism in 59.48% of the evaluated cases. The combined treatment was effective for inducing descent of cryptorchid and gliding testes. According to the evaluated intraoperative findings, the failure of the combined therapy in 40.52% of the cases is due to the fact that the free descent is limited by local factors such as anatomical alterations of the inguinal canal, epididymal abnormalities or ectopic distal attachment of the lig. testis.

Feasibility study on endoscopic suture with the combination of a distal attachment and a rotatable clip for complications of endoscopic resection in the large intestine.

Endoscopic resection has been more frequently performed for increasingly larger intramucosal tumors of the large intestine in recent years. It is reasonable to expect that the larger the resected mucosal surface, the greater is the likelihood of complications such as bleeding or perforation. The aim of this study was to explore the feasibility of endoscopic suture with a distal attachment and a rotatable clip-fixing device for complications of endoscopic resection in the large intestine. The study population consisted of 15 patients who underwent endoscopic clipping therapy following endoscopic resection for intramucosal tumors of the large intestine. With a distal attachment fitted to the distal end of the endoscope, the optimal position for clipping was ensured by pressing the intestinal wall and deflating the intraluminal air little by little. With a rotatable clip-fixing device, the resection site was endoscopically sutured clip by clip. Tumors were of the laterally spreading tumor type in six patients, small sessile polyps in three, and pedunculated polyps in six. The complications consisted of bleeding in 12 patients, overt perforation in one, and latent perforation in two; 14 of the 15 patients underwent successful suturing by this method. The number of clips used ranged from two to seven (mean 4.4). No patients had further complications after the treatment. We conclude that endoscopic suture with the combination of a distal attachment and a rotatable clip-fixing device is very useful for complications of endoscopic resection in the large intestine.

A functional model for whole limb transplantation in the rat.

To develop a functional model for the study of whole limb transplantation, inbred Lewis rats were used as both donors and recipients. In this model, the recipient biceps femoris muscle was elevated from its distal attachment to preserve part of the adductor function of the limb after surgery. The tibial, peroneal, and sural branches of the sciatic nerve were anastomosed separately to provide faster and more precise functional recovery. For control sensory evaluation, the saphenous branches of the femoral nerve were not reattached. A flat intramedullary pin stabilized with methyl methacrylate was used to rigidly immobilize the femur. The transplanted limbs started bearing weight at 17 to 22 days. Walking on the plantar surface of the hock and adduction of the toes gradually decreased, and the rats developed a normal walking pattern. Sciatic and tibial function indexes, based on walking track analysis, correlated well with clinical observations. In this study, a new model for limb transplantation was developed that provided good and reliable sensory and ambulatory recovery.

3447 Ultra-high magnification endoscopy for early stage esophageal cancer.

For purpose of evaluating characteristic microstructure of the early-stage esophageal cancer, ultra-high magnification endoscopic examination was introduced as pretherapeutic in vivo study. Methods: Ultra-high magnification endoscopy (UHME, Q240Z, Olympus, Tokyo) can vary its magnifying rate from eight times to one hundred and fifty times. High-quality pictures can be constantly obtained by attaching a 2-mm depth soft distal attachment onto the tip of UHME. Results: Vascular architecture can be continuously visualized starting from submucosal vein through proper mucosal layer, configurating characteristic fine-vascular network pattern, to intrapapillary capillary loop (IPCL) in the epitherium, which can never be observed during traditional magnifying endoscopic examination with maximal thirty-five magnifications. 0-IIc lesion that was usually observed as a well demarcated red patch, are revealed to be a composite of scattered red dots and a pink homogenous background. Those red dots are disclosed to be changes of IPCL such as dilatation, weaving, irregularity of caliber, which are never observed in normal and esophagitis mucosa. Infiltration depth of the lesions was clearly demonstrated as elongation and destruction of IPCL. We observed one hundred and twelve cases, and overall accuracy was 75%. Conclusion: By utilizing UHME, authurs succeeded to disclose various novel knowledge of microstructure in early esophageal cancer. This information is essential to pre-therapeutic diagnosis.

Stent attachment site–related endoleakage after stent graft treatment: An in vitro study of the effects of graft size, stent type, and atherosclerotic wall changes

Objective: Perigraft endoleakage is a major complication of the endovascular treatment of abdominal aortic aneurysms. The factors that cause this form of endoleakage are not completely identified. The effect of sizing of the prosthesis in combination with either self-expandable or balloon-expandable stents is evaluated in this study. Further, the influence of atherosclerotic changes on endoleakage is evaluated. Methods: Eight human abdominal aortas were assessed macroscopically at 11 sites for the presence of atherosclerotic changes with intravascular ultrasound scanning (IVUS) and with computed tomography (CT). Five aortas were placed in in vitro circulation with physiologic parameters. After the determination of the proximal and distal landing site of the stent graft, the diameter and surface measurements of the cross sections were taken. The stent graft diameters were chosen from 4-mm undersizing to 6-mm oversizing, both for Gianturco stent grafts (William Cook Europe A/S, Bjaeverskov, Denmark) and for Palmaz stent grafts (Cordis/Johnson & Johnston Co, Warren, NJ). After placement of the stent graft, the diameter and surface measurements of the aortic cross section were determined at the proximal and distal stent attachment sites. The presence and size of the folds at the stent attachment site and the interface with the aortic wall were determined with IVUS and angioscopy. Endoleakage was evaluated with angiography. After angioplasty of the stent attachment site, IVUS, angioscopy, and angiography were repeated. Results: Regarding atherosclerotic changes of the aortic wall, the correlations between clinical impression and CT, clinical impression and IVUS, and CT and IVUS were high (r = 0.77, r = 0.79 and r = 0.79, respectively). For the Gianturco stent grafts, no significant relationship existed between the diameters measured before and after stent graft placement, leading to great differences in intended and achieved oversizing. The achieved oversizing was less in the case of minimal atherosclerotic changes of the aortic wall. The Gianturco stent graft followed the aortic wall closely during the heart cycle. The sizes of the folds of the fabric were clearly correlated with the achieved oversizing (r = 0.83; P = .04) and the grade of endoleakage (r = 0.88; P = .022). Angioplasty after stent graft placement had no effect on the diameter and the grade of endoleakage. Palmaz stent grafts did not follow the aortic wall during the heart cycle. A significant correlation existed between oversizing and both space between aortic wall and stent graft (r = –0.88; P = .02) and grade of endoleakage (r = 0.84; P = .036). Grade of endoleakage in the Palmaz stent graft group was less than in the Gianturco stent graft group. Conclusion: With the use of Gianturco stents, a great difference between intended and achieved oversizing is accomplished. The atherosclerotic changes of the aortic wall possibly affect this finding. The configuration of the Gianturco stent results in the formation of fold in the case of oversizing, which is associated with endoleakage. However, the self-expandable character of the stent leads to a close relation to the aortic wall during the heart cycle, and this may possibly accommodate future aortic neck dilation. The Palmaz stent grafts do not follow the aortic wall during the heart cycle, but they do lead to better interface between the graft and the aortic wall, which results in less endoleakage. (J Vasc Surg 1999;30:658-67.)

Embolotherapy of Persistent Endoleaks after Endovascular Repair of Abdominal Aortic Aneurysm with the Ancure-Endovascular Technologies Endograft System

Endoleak is a potential complication after endovascular repair of abdominal aortic aneurysm (AAA). It may result in continued growth of the aneurysm and potentially result in aneurysm rupture. The authors present their experience with embolotherapy in patients with persistent perigraft flow treated with the Ancure-Endovascular Technologies endograft system. Between February 1996 and August 1998, 54 patients underwent successful repair of AAA with use of the Ancure system. All underwent operative angiography and discharge computed tomography (CT). Follow-up included CT at 6, 12, and 24 months, and CT was also performed at 3 months if an endoleak was present on the discharge CT. Persistent endoleak was defined as perigraft flow still present on the 6-month CT. Seven of 21 initial endoleaks persisted at 6 months. Six patients returned for embolization of the perigraft space and outflow vessels including lumbar arteries and the inferior mesenteric artery (IMA). Five of the six patients had leaks from the proximal (n = 1) or distal attachment sites (n = 4) of the Ancure system with outflow into lumbar arteries and/or the IMA; one leak was caused by retrograde IMA flow. The six patients underwent nine embolization procedures with only one minor complication. Follow-up CT showed complete resolution of endoleak and decrease in size of the aneurysm sac in all patients. Although endoleak is commonly seen initially with the Ancure system, persistent leak occurred in 13% of the patients in the study. Persistent flow in most patients arises from a graft attachment site combined with patent outflow vessels such as the IMA or lumbar arteries. Persistent endoleaks can be effectively and safely embolized with use of a combination of coil embolization of the perigraft space and embolization of outflow vessels. Such intervention resulted in a decrease in size of the aneurysm sac.

Endoleak after stent-graft treatment of abdominal aortic aneurysm: a meta-analysis of clinical studies.

Endoleak is the major complication after endovascular treatment of abdominal aortic aneurysm (AAA) and its incidence seems to remain significant. Little is known about the association of device type and configuration with respect to the incidence, location, time of onset and fate of endoleakage. A meta-analysis was performed via a Medline search of clinical studies after 1995 dealing with the endovascular treatment of AAA. Details of number of patients treated, configuration and type of endovascular device were collected. Data concerning site of origin, time of occurrence and fate of the endoleak were retrieved, along with information on change in diameter of the aneurysm with time. The 23 publications included reported on 1189 patients. The 1118 patients with successfully inserted transfemoral endovascular grafts experienced 270 endoleaks (24 per cent). The majority arose from the distal stent attachment site (36 per cent), were present immediately after stent-graft placement (66 per cent) and were persistent in time (37 per cent). Tube grafts were more frequently affected by endoleakage (35 per cent; P < 0.0001), especially at the distal stent attachment site (51 per cent), than bifurcated grafts (18 per cent; P = 0.004) and aortounilateral devices (20 per cent; P = 0.70). Self- expandable stent-grafts were more frequently associated with endoleaks (25 per cent) than balloon-expandable stent-grafts (17 per cent) (P = 0.037). Endovascular treatment of AAA is an evolving field. Even after the initial learning curve and attention to device-related problems, it is still accompanied by a significant number of endoleaks. Uniform presentation of results of treatment is necessary for analysing the effect of differences between patients, aneurysm morphology and device type.

Immediate and late explantation of endovascular aortic grafts: The Endovascular Technologies experience

Purpose: The morbidity and clinical outcome of the failure to successfully repair an abdominal aortic aneurysm with Endovascular Technologies (EVT) grafts, resulting in explantation of the device, was assessed. Methods: The records of all patients worldwide undergoing attempted endovascular repair with EVT devices from February 1993 to October 1997 were retrospectively reviewed. Of 669 patients, 19 (3%) were converted to open procedure with immediate explantation during the initial attempt at endovascular repair, and 27 patients (4%) required explantation at a later date, ranging from 1 day to 40 months. The incidence, morbidity, mortality, and effect on clinical outcome were evaluated. Results: Causes of immediate conversion with explantation were: inaccurate deployment of the proximal or distal attachment systems (11 of 19; 58%); twists in the system (3 of 19; 16%); mechanism malfunction during deployment (4 of 19; 21%); and an aortic tear (1 of 19; 5%). Among the 27 patients undergoing late explantation, 20 (74%) did so because of persistent endoleaks. Three cases (11%) were performed because of aneurysm rupture, three (11%) because of graft occlusion, one because of aortic dissection (4%), and one (4%) because of graft migration into the aneurysm sac. The overall perioperative mortality rate was 11% (2 of 19) for immediate explantation and 7% (2 of 27) for late explantation. The average length-of-stay was 11 days for immediate explantation and 14 days for late explantation (NS). Complications included myocardial infarction (4%), pulmonary insufficiency (13%), wound infection (4%), and permanent renal failure (2%). There were no significant differences in the incidence rates of these complications between immediate and late explants. No cases of limb loss occurred. Median American Society of Anesthetists (ASA) classification was 3, and there was no correlation between ASA classification and mortality rate. Average operating time was 374 minutes for immediate explantation (including the time for the failed endovascular procedure) and 185 minutes for late explantation. Conclusion: Immediate and late explantation are infrequent events, occurring in 3% and 4%, respectively, of attempted EVT endovascular aortic stent placements. The mortality rate was higher for both immediate (11%; P < .05) and late (7%; NS) explantation when compared with the mortality rate of all patients undergoing EVT aortic endograft placement (1.5%). There does not appear to be increased long-term morbidity among patients undergoing successful explantation. Early recognition of the need to convert to open procedure, device improvement, and increased operator experience should continue to minimize the incidence of immediate and late explantation and their associated complications. (J Vasc Surg 1999;29:309-16.)

The fate of the infrarenal aortic neck after open aneurysm surgery

Purpose: The long-term success of the endovascular repair of abdominal aortic aneurysms is dependent on the secure fixation of the stent graft at the proximal and distal attachment sites. A progressive dilatation of the infrarenal neck may jeopardize this success. The data regarding this issue are scarce. However, the long-term fate of the infrarenal neck can be studied in patients who have undergone open aneurysm surgery. This was the purpose of the present investigation. Methods: Between January 1989 and December 1993, 64 patients underwent open repair of infrarenal abdominal aortic aneurysms. Of the 36 patients who were eligible for the study, 19 had preoperative computed tomography scans that were available. The 19 patients also underwent a new computed tomography scanning at a mean of 71 ± 12 months after surgery. Results: The mean preoperative aortic diameter was 25.4 ± 3.7 mm at the infrarenal neck, 24.8 ± 3.4 mm at the level of the renal arteries, and 26.7 ± 3.0 mm at the level of the superior mesenteric artery (SMA). The mean aortic diameter increased at all of the 3 levels: +2.8 ± 3.1 mm ( P = .0014) at the infrarenal neck, +2.8 ± 3.0 mm ( P = .0013) at the level of the renal arteries, and +1.3 ± 3.0 mm ( P = .080) at the level of the SMA. The annual growth rate was 0.48 mm/y ( P = .0023) at the infrarenal neck, 0.46 mm/y ( P = .0010) at the level of the renal arteries, and 0.21 mm/y ( P = .5811) at the level of the SMA. No correlation was found between the preoperative infrarenal neck diameter ( r = .295, P = .2194), the preoperative aortic diameter at the level of the renal arteries ( r = .302, P = .2088), and the preoperative aortic diameter at the level of the SMA ( r = .314, P = .2043) and the corresponding growth rates. The patients were stratified into 2 groups—one with a small annual growth rate at the infrarenal neck (n = 11; ≤0.3 mm/y) and one with a larger annual growth rate (n = 8; >0.3 mm/y)—and no differences in the preoperative infrarenal neck diameter or the clinical characteristics were found between the groups. Conclusion: This investigation shows an aortic dilatation of the infrarenal neck and of the aorta at the level of the renal arteries of approximately 0.5 mm annually after open aneurysm surgery. This dilatation raises concern regarding the long-term success after endovascular repair. The data also indicate that 2 populations might exist with regard to the annual growth rate of the infrarenal neck—one with low growth rate and one with higher growth rate. This might be of interest for the future selection of patients for endovascular repair. (J Vasc Surg 1998;28:889-94.)

Continued expansion of aortic necks after endovascular repair of abdominal aortic aneurysms

Background: Longitudinal studies have revealed that the aortic segment proximal to an infrarenal abdominal aortic aneurysm (AAA) is at risk for continued enlargement after a standard aneurysm repair. Similarly, preliminary reports have shown expansion of one or both aortic necks after endovascular repair. Although some investigators have suggested that this may be a transient effect, continued dilatation at the endograft attachment site could effect the overall device stability. Methods: As part of a multi-institutional trial of endovascular grafting for the treatment of AAA, 59 patients were successfully implanted with straight endografts between February 1993 and January 1995. A morphometric analysis of aortic neck size was undertaken with serial review of computed tomography scans available through April 1997. The neck sizes at both graft attachment sites were measured, with investigators blinded to patient identity and date of scan. Changes in minor diameter were defined, annual interval expansion rates were calculated, and the data were correlated with endoleak, device migration, aneurysm size change, endograft diameter, attachment system fractures, and initial preimplant neck size. Results: Significant aortic neck enlargement, particularly at the level of the distal neck, was observed for at least 24 months after AAA repair. The annual interval dilation rates of the proximal aortic neck were 0.7 ± 2.1 mm/y ( P = .023) and 0.9 ± 1.9 ( P = .008) mm/yr during the first and second years, respectively. Enlargement of the distal neck during the observation period was more marked, with corresponding annual expansion rates of 1.7 ± 2.9 mm/y ( P < .001) and 1.9 ± 2.5 ( P < .001) mm/year. In 5 patients (14%), the minor diameter of the distal neck was at least 6 mm larger than the preimplant diameter of the graft. Migration of the distal attachment system was observed in 3 of these 5 patients. Expansion rates did not have a statistically significant correlation with initial neck size, endograft dimensions, aneurysm size change, presence of endoleak, or attachment system fracture. Conclusions: Aortic neck enlargement was observed for at least 2 years after endovascular grafting. Close patient follow-up remains mandatory in lieu of the potential risk of late failure as a result of continued aortic expansion. The relative contribution of device design to this phenomenon will need to be defined. (J Vasc Surg 1998;28:422-31.)

Ultrasound Evaluation of Endovascular Repair of Abdominal Aortic Aneurysms

Endovascular repair of an abdominal aortic aneurysm (AAA) offers a minimally invasive alternative to an open surgical procedure in selected patients. The purpose of this study was to examine the usefulness of ultrasonography for evaluating the results of endovascular repair. Methods: We studied 17 patients who underwent endovascular repair. In 10 patients a bifurcated prosthesis was positioned below the renal arteries with the bifurcated branches in the iliac arteries. The other 7 patients had a nonbifurcated infrarenal prosthesis. Results: In each patient the AAA and the entire prosthesis, including its bifurcated branches, were visualized. The mean AAA diameter was 5.0 ± 0.6 cm. The mean prosthesis body diameter was 2.2 ± 0.3 cm, and the diameters of the bifurcated limbs were 1.0 to 1.2 cm. Color Doppler studies revealed blood flow limited to the prosthetic lumen and its bifurcation in 16 patients; the space between the prosthesis and the AAA wall was clotted in these patients. In 1 patient a communication was seen between the prosthesis and the AAA lumen through a dehiscence in the distal attachment. Conclusion: Ultrasonography is a simple, noninvasive tool for the evaluation of the results of endovascular repair of AAA and can detect complications of this procedure. (J Am Soc Echocardiogr 1998;11:377-80.)

Topographical anatomy of the penile arteries.

To determine the relationship of the penile arteries to anatomical landmarks and thus ease their identification, so avoiding injury during surgery. The penile arteries in 12 formalin-preserved adult male cadavers were dissected and the distances measured between the cavernosal arteries and both the endopelvic fascia and distal attachment of the crura to the ischial bones. The distance between the origins of both bulbar and cavernosal arteries, their length and the length of the cavernosal bodies and crural attachments were also measured. Several anatomical variations, e.g. accessory pudendal arteries, multiple cavernosal and bulbar arteries, irrigation of cavernosal bodies by contralateral branches, anastomosis of cavernosal arteries with accessory pudendal branches, dorsal artery or bulbar artery as main branches of accessory pudendal arteries, were observed in 13 of the 24 specimens. The mean distances between the anterior attachment of the crura to the ischial rami and the site on the tunica albuginea where the cavernosal arteries penetrated the cavernosal bodies were 1.26 cm on the right and 0.69 cm on the left. The corresponding measurements between the cavernosal arteries and the endopelvic fascia were 5.68 cm (right) and 4.85 cm (left). The mean extracavernosal lengths of the right and left cavernosal arteries were 2.47 and 2.2 cm, respectively. Multiple anatomical variations of the arterial penile anatomy occur frequently. Surgery at the penile hilum may easily damage the cavernosal arteries, which lie medially to the dorsal nerves and arteries of the penis, have an extracavernosal length of about 2.3 cm and perforate the tunica albuginea about 1 cm distally to the anterior attachment of the crura to the ischial ramus.

Computed tomographic angiographic imaging of abdominal aortic aneurysms: implications for transfemoral endovascular aneurysm management.

To describe anatomic features pertinent to patient selection and graft design for transfemoral endovascular aneurysm management (TEAM) of the infrarenal aorta using computed tomographic (CT) angiography. A prospective noncomparative analysis of 102 spiral CT scans of the abdominal aorta of patients with abdominal aortic aneurysms was performed. From the original CT data set, slices were reconstructed perpendicular to the vessel axis (central lumen line) at a 10 mm interval. In these reconstructed slices, diameter measurements were performed. Vessel length was measured along the central lumen line. In each patient possibilities for TEAM were analyzed. Because of technical reasons, 36 scans were excluded from the analysis. Of the remaining 66 patients, 18 could potentially be treated with a bifurcated endovascular device. The infrarenal aortic diameter-to-iliac artery diameter ratio was less than 2 in most patients. The vessel segments judged to be adequate for endovascular graft anchoring had a noncylindrical shape in the majority of cases. Only a minority of patients with abdominal aortic aneurysms can at this stage be treated with an endovascular graft. The ideal endovascular graft should be a combination of rigid and flexible components. The proximal and distal attachment systems should have some flexibility with an intrinsic maximum diameter while the midsection of the graft can be relatively rigid.

CDNA Cloning, Genomic Organization, and in Vivo Expression of Rat N-syndecan

The amino acid sequence of rat N-syndecan core protein was deduced from the cloned cDNA sequence. The sequence predicts a core protein of 442 amino acids with six structural domains: an NH2-terminal signal peptide, a membrane distal glycosaminoglycan attachment domain, a mucin homology domain, a membrane proximal glycosaminoglycan attachment domain, a single transmembrane domain, and a noncatalytic COOH-terminal cytoplasmic domain. Transfection of human 293 cells resulted in the expression of N-syndecan that was modified by heparan sulfate chain addition. Heparitinase digestion of the expressed proteoglycan produced a core protein that migrated on SDS-polyacrylamide gels at an apparent molecular weight of 120, 000, identical to N-syndecan synthesized by neonatal rat brain or Schwann cells. Rat genomic DNA coding for N-syndecan was isolated by hybridization screening. The rat N-syndecan gene is comprised of five exons. Each exon corresponds to a specific core protein structural domain, with the exception of the fifth exon, which contains the coding information for both the transmembrane and cytoplasmic domains as well as the 3'-untranslated region of the mRNA. The first intron is large, with a length of 22 kilobases. The expression of N-syndecan was investigated in late embryonic, neonatal, and adult rats by immunoblotting and Northern blotting analysis. Among the tissues and developmental stages studied, high levels of N-syndecan expression were restricted to the early postnatal nervous system. N-syndecan was expressed in all regions of the nervous system, including cortex, midbrain, spinal cord, and peripheral nerve. Immunohistochemical staining revealed high levels of N-syndecan expression in all brain regions and fiber tract areas.

Effects of overdenture retention designs and implant orientations on load transfer characteristics

Various approaches have been used for the retention and stabilization of implant-supported overdentures. This study examined photoelastically the simulated load transfer characteristics of a resilient cap attachment with moderately atrophied mandibular plastic models with two implant orientations. Comparison was made with overdentures supported by a splinting bar and a bar with distal resilient cap attachments. Stress patterns developed by simulated occlusal loading demonstrated little cross-arch load sharing and more uniform stress distribution with noninclined implants for all retention designs. The most equitable simulated occlusal force transfer was provided by the resilient cap attachments direct to the implants.