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PubMed2003

Portal vein resection and reconstruction prior to hepatic dissection during right hepatectomy and caudate lobectomy for hepatobiliary cancer.

BACKGROUND: Hepatobiliary cancer invading the hilar bile duct often involves the portal bifurcation. Portal vein resection and reconstruction is usually performed after completion of the hepatectomy. This retrospective study assessed the safety and usefulness of portal vein reconstruction prior to hepatic dissection in right hepatectomy and caudate lobectomy plus biliary reconstruction, one of the common procedures for radical resection. METHODS: Clinical characteristics and perioperative results were compared in patients who underwent right hepatectomy and caudate lobectomy plus biliary reconstruction with (ten patients) and without (11 patients) portal reconstruction from September 1998 to March 2002. RESULTS: All ten portal vein reconstructions were completed successfully before hepatic dissection; the portal cross-clamp time ranged from 15 to 41 (median 22) min. Blood loss, blood transfusion during the operation, postoperative liver function, morbidity and length of hospital stay were similar in the two groups. No patient suffered postoperative hepatic failure or death. CONCLUSION: This study demonstrates that portal vein reconstruction does not increase the morbidity or mortality associated with right hepatectomy and caudate lobectomy with biliary reconstruction. This approach facilitates portal vein reconstruction for no-touch resection of hepatobiliary cancer invading the hilar bile duct.

Aged↗

PubMed1986

Augmentation of anterior cruciate ligament reconstruction in dogs with prostheses of different stiffnesses.

The purpose of this study was to investigate the biological and biomechanical properties of anterior cruciate ligament (ACL) reconstruction augmented with Dacron prostheses of three different stiffnesses. The ACLs of 36 adult mongrel dogs were removed and the ligament was reconstructed. In 18 dogs, one knee was reconstructed with patellar tendon alone, and the contralateral knee with Dacron augmented patellar tendon. In the remaining 18 dogs, reconstruction was with Dacron augmented patellar tendon with Dacron alone being used for the contralateral control knee. Death was 3 months after surgery, and the reconstructions were examined biologically and biomechanically. The mechanical data were compared with immediate postoperative data obtained from 45 reconstructed fresh cadaveric knees. Tensile testing demonstrated that an increase in failure load was found when the implanted patellar tendon graft was compared with the cadaveric reconstruction. The strength of the Dacron augmented reconstruction showed little change while the Dacron alone graft decreased in strength during the period of implantation. No clear difference was found between the performance of augmentation devices of different stiffnesses. Microangiography showed that grafts were totally revascularized in patellar tendon alone, but not well revascularized in Dacron augmented patellar tendon and Dacron alone reconstruction. The presence of the Dacron appeared to have an adverse effect on revascularization.

Animals↗

PubMed2006

Breast reconstruction with alloplastic implants.

This article reviews immediate and delayed breast reconstruction with prosthetic implants, and the effect of irradiation therapy. Despite widespread use of breast conserving surgery for early breast cancer, many breast cancer patients still undergo mastectomy. Some of these patients choose breast reconstruction. Over the last 30 years, techniques for breast reconstruction have evolved significantly with new alternative techniques and improved surgical devises. Immediate or delayed breast reconstruction with silicone prosthesis can be an excellent option. Implant reconstruction may be single or two stage procedures. Traditionally, small breasts with minimal ptosis are suited for single-stage reconstruction. Large breasts or inadequate skin require expanders followed by implants. Minimal excision mastectomy and biological spacers are allowing larger breast single stage reconstruction and improved aesthetics for two stage procedures. With recent studies suggesting survival advantage of post-mastectomy irradiation, many candidates for breast reconstruction are receiving radiotherapy, which complicates healing after breast reconstruction.

Breast Implants↗

PubMed2007

Effect of cytoplast on the development of inter-subspecies nuclear transfer reconstructed goat embryo.

The aim of this study was to investigate effect of cytoplast on the development competence of reconstructed embryos derived from inter-subspecies somatic cell nucleus transfer (SCNT). First, the development potency of reconstructed embryos produced by transferring Boer goat fibroblast cell nucleus of different ages into enucleated Sannen goat ova was evaluated in order to determine which age of nuclear donor is favorable for the reconstructed embryos development. Secondly, the another component of reconstructed embryos, "cytoplast," was evaluated by comparing the effect of ovum cytoplast derived from Sannen male symbol x Boer female symbol descendant on the reconstructed embryos development to that of Sannen goat ovum cytoplast. The results revealed that the development rate of the reconstructed embryos derived from 2 months old Boer goat somatic cells was the highest, their gestation rate was up to 50%, and one viable male offspring was obtained. The cytoplast derived from the crossbreeding goats improves the development competence of reconstructed embryos, which birth rate was 5.5%. The genetic identification of offspring by using PCR-SSCP analysis confirmed that these cloned kids were derived from the donor. The results above reveal that the cytoplast of Sannen goat ovum could induce the dedifferentiation of somatic cell nuclei derived from Boer goat, but the reprogramming process of these reconstructed embryos seems incomplete, probably due to some incorrect processes happened after implantation. Relatedness components of nucleus donor in cytoplast of the crossbreeding goat may be helpful to induce the dedifferentiation of somatic cell nuclei completely and improve the development competence of the reconstructed embryos.

Animals↗

PubMed1988

Breast reconstruction after mastectomy.

The goal of breast reconstruction is to reconstruct breasts which meet the patient's expectations both psychologically and aesthetically, while adhering to the principles of sound oncological management. Breast reconstruction is usually started around 3 to 9 mos after mastectomy. The simplest method of reconstruction uses tissue available after mastectomy and a silicone implant. The recent advances with tissue expansion of the skin of the mastectomy site can permit reconstruction without the use of a flap. The latissimus dorsi flap from the back is a useful source of muscle and skin and the transverse rectus abdominus musculocutaneous flap provides tissue from the lower abdomen enabling breast reconstruction without the use of a silicone implant. Fat and skin from the buttocks may be used in a microsurgical transfer technique. Prophylactic mastectomy and immediate breast reconstruction are still controversial, but are options for the woman who is worried about the development of breast cancer. The reconstruction of the nipple and areola is only done after reconstructed breast symmetry is ascertained.

Adult↗

PubMed1996

Aortic reconstruction in kidney transplant recipients.

Renal transplantation has increased the longevity of patients with uremia. An increasing number undergo aortic reconstruction, which exposes the transplanted kidney to ischemic injury. To evaluate the risk for renal failure, loss of the transplant, and methods of renal protection, we reviewed our experience. Clinical data were reviewed for 10 consecutive patients (7 men, 3 women; mean age 52.7 years [range 32 to 75 years]) with a transplanted kidney who underwent aortic reconstruction between 1977 and 1994 at our institution. Mean interval between renal transplantation and aortic reconstruction was 5.9 years (range 1 month to 12.7 years). Seven patients required emergency repair because of dissection (2 patients), aneurysm rupture (4 patients), or symptomatic aneurysm (1 patient); three underwent elective repair. Reasons for reconstruction included aortic dissection (2 patients), aneurysm of the descending thoracic (2 patients), thoracoabdominal (1 patient), or abdominal aorta (3 patients), and aortoiliac occlusive disease (2 patients). Patients with thoracic or thoracoabdominal reconstructions underwent repair with atriofemoral, aortofemoral, or femorofemoral shunt placement or bypass. Of the five abdominal aortic reconstructions, the kidney was protected with aortofemoral shunt placement in one patient and cold renal perfusion in three. In two of them, topical cooling of the kidney also was used. One patient with acute aortic dissection died at 39 days as a result of respiratory failure. Loss of the recently transplanted kidney was caused by acute rejection. One patient had a transient increase in serum creatinine concentration. Eight no worsening of renal function, and none of the nine survivors lost the transplanted kidney. We concluded that aortic reconstruction can be safely performed in kidney transplant recipients. Patients in whom thoracic or thoracoabdominal aortic reconstruction was required were protected with an atriofemoral or aortofemoral bypass or shunt. Patients undergoing abdominal aortic reconstruction did well when cold renal perfusion with or without local cooling of the transplant was used for renal protection. Transplanted kidneys appeared to tolerate ischemic injury similarly to native kidneys.

Adult↗

PubMed1992

Effect of radiographic landmark identification errors on the accuracy of three-dimensional reconstruction of the human spine.

In three-dimensional reconstruction of the human spine obtained from stereo-radiographic set-ups (two radiographs or more), it is extremely difficult to identify exactly the same landmarks on all radiographs. The effect of these identification errors was investigated with simulations made on points of known three-dimensional co-ordinates and compared with three-dimensional reconstructions of real spines obtained with the direct linear transformation algorithm. Results showed that radiographic identification errors of up to 2 mm were common, causing reconstruction errors of up to 5 mm. These reconstruction errors may be noticed in the form of geometrical inaccuracies in the graphical representation of three-dimensional reconstructions of the spine. Successive displacements were then imposed on image point co-ordinates to minimise the identification error and increase the reconstruction accuracy. The improvement on the three-dimensional reconstruction results was negligible. Three-dimensional reconstructions obtained from three radiographs were also investigated. They showed slightly more accurate reconstructions than those obtained from two radiographs. However, the increase of X-ray exposure on the patient may not be worthwhile.

Algorithms↗

PubMed2002

[Status of aortic valve reconstruction and Ross operation in aortic valve diseases].

BACKGROUND: At first glance the aortic valve is a relative simple valve mechanism connecting the left ventricle and the ascending aorta. Detailed analysis of the different components of the aortic valve including the leaflets and sinuses revealed a complex motion of each part leading to a perfect durable valve mechanism at rest and during exercise. Theoretically, the reconstruction or imitation of these structures in patients with aortic valve disease should lead to optimal results. Prerequisite is the exact knowledge of the important functional characteristics of the aortic valve. The dynamic behavior of the aortic root closely harmonizing with the leaflets not only warrants stress minimizing and valve durability, but also optimizes coronary flow, left ventricular function and aortic impedance. The newly discovered contractile capacity of the leaflets and the root components are important for tuning the dynamics. AORTIC VALVE RECONSTRUCTION: Isolated reconstruction of the aortic valve such as decalcification, commissurotomy, plication of ring or leaflets of a tricuspid aortic valve and cusp extension are seldom indicated in contrast to the reconstruction of the bicuspid insufficient valve. Proper indication and skilled techniques lead to excellent hemodynamic and clinical intermediate-term result up to 7 years after reconstruction. Latest follow-up revealed a mean aortic insufficiency of 0.7, maximal pressure gradient of 11.4 +/- 8.5 mm Hg with zero hospital or late mortality, reoperation or thromboembolic events in 22 patients. The reconstructive techniques for aortic root aneurysm and/or type A dissection according to David or Yacoub have become routine procedures in the last 10 years. The hemodynamic and clinical results are excellent with low reoperation rate and very low risk of thromboembolism. Generally, a maximal diameter of the root of 5 cm is indicative for performing the operation. In patients with Marfan's syndrome the reconstruction should be advanced even with smaller diameters especially if these are progressive and combined with aortic insufficiency. ROSS-OPERATION: The Ross-Operation includes the replacement of the diseased aortic valve with the pulmonary autograft and reconstruction of the right ventricular outflow tract using a homograft. The hemodynamic results are excellent regarding the autograft and also the clinical results with very low thromboembolic risk and acceptable reoperation rate. This method is especially indicated for active young patients, women, who desire children, athletes and patients in general, who like to avoid long-term anticoagulation. In some cases the homograft may develop a dysfunction predominantly a pulmonary stenosis requiring reoperation. In the author's series of 245 Ross-operations in 12 years the homograft had to be replaced in 4 cases without letality. Innovative, decellularized homografts with the potential to repopulate with autologeous cells show promising results after 1 year of clinical implantation without signs of antibody development. Probably these tissue-engineered modification may improve the homograft results. The reconstructive techniques of the aortic valve and the Ross-operation have a certain risk of reoperation that must be weighed against the advantages of very low hospital and late valve related death, excellent hemodynamics, very low risk of macro- and microembolism as well as bleeding, lack of long-term anticoagulation and unrestricted life-style.

Adult↗

PubMed2006

ACL reconstruction: patellar tendon versus hamstring grafts--economical aspects.

The aim of the present investigation was to compare the costs for the use of patellar tendon versus hamstring tendons as grafts for anterior cruciate ligament (ACL) reconstruction including the different fixation methods. The background is that during recent years there has been a dramatic shift from patellar tendon to hamstring tendons in ACL reconstructions in Sweden. All our patients with ACL reconstructions performed during 1 year (2004) were included. Knee joints numbering 440 in 439 patients were primary ACL reconstructions. A hamstring graft was used in 345 knee joints (78.4%) and a patellar tendon graft in 95 (21.6%) of the patients (Table 2). On average 34 (SD 12.9; range 14-63) ACL reconstructions per surgeon were performed by a total of 14 surgeons. The average cost for patellar tendon procedure was 197 euros compared to 436 euros for the hamstring procedure. Mean time for surgery in primary reconstructions was 11.5 min shorter (P<0.001) for patellar tendon reconstructions (71.3+/-31 min) compared to hamstring reconstructions (83.2+/-27 min). This means a difference in cost of 90 euros. The total additional cost (fixation and surgery time) for the hamstring method compared to the patellar tendon method was on an average 329 euros. From a strict economic point of view we therefore recommend or at least consider the use of the patellar tendon as a graft in ACL reconstructions.

Adult↗

PubMed2006

Kinematic study following double-bundle, anterior cruciate ligament reconstruction.

The purpose of this study was to evaluate tibiofemoral kinematics after double-bundle anterior cruciate ligament (ACL) reconstructions and compare them with those of successful single-bundle reconstructions and contralateral normal knees using open MR images. We obtained MR images based on the flexion angle without weight-bearing, from 20 patients with successful unilateral single-bundle (10 patients) and double-bundle (10 patients) ACL reconstructions with tibialis anterior allografts and a minimum 1-year follow-up. The MR images of the contralateral uninjured knees were used as normal controls. Sagittal images of the mid-medial and mid-lateral sections of the tibiofemoral compartments were used to measure the translation of the femoral condyles relative to the tibia. The mean translations of the medial femoral condyles on the tibial plateaus during knee joint motion showed no significant differences among normal, single-bundle, and double-bundle ACL reconstructed knees (all p>0.05). The mean translations of the lateral femoral condyles showed a significant difference between normal and single-bundle reconstructed knees, or between single-bundle and double-bundle reconstructed knees (p<0.05). However, there was no significant difference between normal and double-bundle reconstructed knees (p=0.220). These findings suggest that double-bundle ACL reconstruction restores normal kinematic tibiofemoral motion better than single-bundle reconstruction.

Anterior Cruciate Ligament↗

PubMed1996

Importance of the duodenal passage and pouch volume after total gastrectomy and reconstruction with the Ulm pouch: prospective randomized clinical study.

The objective of this randomized study was to examine which reconstruction method and which pouch volume offer the best preconditions for a good quality of life and extensive physiologic regulation of gastrointestinal hormones after total gastrectomy. Up to now there is no general agreement with regard to the ideal reconstruction after total gastrectomy. The importance of the duodenal passage, the need for a pouch reconstruction, and the ideal pouch volume are matters of controversy. A total of 60 patients underwent the following reconstructions: Ulm pouch (pouch reconstruction with preservation of the duodenal passage), Hunt-Lawrence-Rodino pouch, or Roux-en-Y reconstruction without pouch. The clinical course, quality of life, and regulation of gastrointestinal hormones in correlation to reconstruction type and pouch volume were documented. Quality of life was assessed by means of a standardized specific questionnaire. Blood glucose, insulin, cholecystokinin, motilin, secretin, and pancreatic polypeptide were measured after stimulation by a standardized test meal. Six months after total gastrectomy those patients with an Ulm pouch were found to have a significantly better life quality (p < 0.01), higher body weight, and better physiologic regulation of gastrointestinal hormones; moreover, they developed (in contrast to all other reconstruction types) no pathologic glucose tolerance. Our conclusion is that all patients with a postoperative life expectancy of at least 6 months (i.e., tumor stages UICC I and II) should undergo pouch reconstruction with preservation of the duodenal passage.

Aged↗

PubMed2002

Heart-rate-adapted image reconstruction in multidetector-row cardiac CT: influence of physiological and technical prerequisite on image quality.

The purpose of this study was to develop strategies for optimal image reconstruction in multidetector-row cardiac CT and to discuss the results in the context of individual heart rate, cardiac physiology, and technical prerequisite. Sixty-four patients underwent multidetector-row cardiac CT. Depending on the heart rate either a single-segmental reconstruction (SSR) or an adaptive two-segmental reconstruction (ASR) was applied. Image reconstruction was done either antegrade (a) or retrograde (r) in relation to the R-peak. Reconstruction of all data sets was performed at multiple time points within the t-wave/p-wave interval, differing from each other by 50 ms. In addition, each reconstruction was assigned to one of six reconstruction intervals (A-F), each corresponding to a specific event in the cardiac cycle. While no significant time points were found for absolute values, the following interval/reconstruction technique combinations provided significant better image quality: F/r at HR <60 bpm for all coronary segments ( p</=0.004) and at HR 60-65 bpm for segments 5-10 ( p</=0.001); B/a at HR 60-65 bpm for segments 1-4 and 11-15 ( p<0.001) and at HR >65 bpm for all segments ( p</=0.002). The results show that in order to achieve optimal image quality, image reconstruction has to be adjusted to each patient's ECG curve and heart rate individually. The moment of reconstruction should be determined as absolute rather than as relative distance from the previous R-peak.

Algorithms↗

PubMed1998

Aortoiliac reconstruction and kidney transplantation: a multicenter study.

The occurrence of aortoiliac lesions with renal transplantation is an increasingly common combination that causes problems regarding operative strategy and indications for aortoiliac reconstruction and renal transplantation. To gain greater insight into these problems we undertook a retrospective multicenter study based on data from 24 kidney transplantation centers in France. A total of 83 patients who underwent both aortoiliac reconstruction and kidney transplantation were enrolled. Patients were divided into two groups according to the order in which the two procedures were performed. Group I included 36 patients in whom aortoiliac reconstruction was performed before kidney transplantation-either during the same procedure (6 patients) or as separate procedures (30 patients). Group II included 47 patients in whom aortoiliac reconstruction was performed after kidney transplantation. The mean age was 49.9 years. There were 43 abdominal aortic aneurysms (51.8%), 36 occlusive aortoiliac lesions (43.4%), and 4 aortoiliac dissections (4.8%). Prosthetic bypass grafting was performed in 72 cases (86.8%), transluminal angioplasty in 6 cases (7.2%), endarterectomy in 3 cases (3.6%), and arterial autograft bypass in 1 case. Renal transplant protection was used during aortoiliac clamping in only 3 patients in group II (7.3%). One month after the second procedure (i.e., kidney transplantation in group I and aortoiliac reconstruction in group II), creatinemia was <200 micromol/L in 27 patients (87.1%) in group I and in 37 patients (88.1%) in group II. The graft survival rate was 86.1% in group I and 89.3% in group II. The overall postoperative morbidity rate was 36.1% (13 cases) in group I and 36.1% (17 cases) in group II. One year after the second procedure creatinemia was <200 micromol/L in 29 patients (93.5%) in group I and 36 patients (93%) in group II. The graft survival rate was 86.1% in group I and 85.1% in group II. The outcome of kidney transplantation is comparable regardless of whether the procedure is performed alone or in association with aortoiliac reconstruction. This finding indicates that kidney transplantation should be performed in patients presenting indications for prior aortoiliac reconstruction. The outcome of aortoiliac reconstruction without graft protection in kidney transplant patients is comparable to the outcome of conventional aortoiliac reconstruction in patients with native kidneys.

Angioplasty↗

PubMed2001

An outcome study of breast reconstruction: presurgical identification of risk factors for complications.

BACKGROUND: Breast reconstruction following mastectomy has been shown to have a salutary effect on the overall psychological well-being of women being treated for breast cancer. Unfortunately, however, not every patient is an ideal candidate for reconstruction. Complications stemming from reconstructive surgery can cause significant morbidity, the most important of which may be the delay of subsequent adjuvant antineoplastic therapies, and therefore may not be in the best interests of the patient. METHODS: A retrospective study was performed on a consecutive series of 123 breast reconstructions in 98 patients, performed by one of two plastic surgeons, in a university setting over a 5-year period, for all surgical outcomes. Specifically, wound-healing complications, infections, and reoperations leading to the potential delay of subsequent chemotherapy or radiotherapy were recorded, and possible risk factors leading to these were sought. RESULTS: Three presurgical risk factors were found to have a statistically significant influence on the development of complications following breast reconstruction. These were: (1) increasing obesity, defined by the body mass index, (2) an active or recent (<5 year) history of cigarette smoking, and (3) a history of previous radiation exposure. Odds ratios were used to describe the magnitude of the effect of each factor for the development of complications. An ordinal regression analysis was used to create a nomogram based on this information that can be used to calculate any individual patient's presurgical risk for developing major complications following breast reconstruction, based on the presence of these factors. CONCLUSIONS: It is possible, based on the presence of specific presurgical risk factors, to predict the probability of developing major complications following breast reconstruction. This information can be useful to the referring physician and plastic surgeon alike in determining which patients are the best candidates for breast reconstruction and which type of reconstruction would be best suited for each individual patient.

Adult↗

PubMed2005

A computer reconstruction of the entire coronary arterial tree based on detailed morphometric data.

A rigorous analysis of blood flow must be based on the branching pattern and vascular geometry of the full vascular circuit of interest. It is experimentally difficult to reconstruct the entire vascular circuit of any organ because of the enormity of the vessels. The objective of the present study was to develop a novel method for the reconstruction of the full coronary vascular tree from partial measurements. Our method includes the use of data on those parts of the tree that are measured to extrapolate the data on those parts that are missing. Specifically, a two-step approach was employed in the reconstruction of the entire coronary arterial tree down to the capillary level. Vessels > 40 microm were reconstructed from cast data while vessels < 40 microm were reconstructed from histological data. The cast data were reconstructed one-bifurcation at a time while histological data were reconstructed one-sub-tree at a time by "cutting" and "pasting" of data from measured to missing vessels. The reconstruction algorithm yielded a full arterial tree down to the first capillary bifurcation with 1.9, 2.04 and 1.15 million vessel segments for the right coronary artery (RCA), left anterior descending (LAD) and left circumflex (LCx) trees, respectively. The node-to-node connectivity along with the diameter and length of every vessel segment was determined. Once the full tree was reconstructed, we automated the assignment of order numbers, according to the diameter-defined Strahler system, to every vessel segment in the tree. Consequently, the diameters, lengths, number of vessels, segments-per-element ratio, connectivity and longitudinal matrices were determined for every order number. The present model establishes a morphological foundation for future analysis of blood flow in the coronary circulation.

Algorithms↗

PubMed1984

Trends in reconstruction for atherosclerotic renal vascular disease.

Twenty-eight patients underwent renal vascular reconstruction for atherosclerotic renal vascular stenosis. Ten patients had therapeutic renal artery reconstruction for isolated renal artery stenosis causing severe hypertension, nine patients had therapeutic renal artery reconstruction for severe hypertension combined with simultaneous aortic reconstruction, and nine patients had prophylactic renal artery reconstruction for renal artery stenosis combined with simultaneous aortic reconstruction. Ninety percent of patients undergoing therapeutic renal revascularization procedures for hypertension were cured or improved. The 10 patients undergoing prophylactic renal artery reconstruction combined with aortic reconstruction had an average 72 percent reduction in the diameter of the vessel. Dacron side grafts sutured to the aortic graft were used for revascularization in each of the patients with prophylactic revascularization and was found to be an expedient means of reconstruction with good patency rates. No increased morbidity or mortality rate was noted in the prophylactic group. We believe that prophylactic revascularization should be carried out in patients with atherosclerotic high-grade stenosis of the renal arteries to prevent hypertension and preserve renal function.

Aged↗

PubMed1983

A simple microcomputer-based three-dimensional serial section reconstruction system (MICROS).

We have developed a computer system which enters and aligns serial sections and displays the completed reconstructions at different rotations in space. The system uses commercially available hardware, including a Hewlett-Packard 9845T microcomputer and an H-P 9874A digitizer. The software for the system is written in the BASIC language. The system consists of two programs, one for section digitization, the other for rotation and display of the reconstructions. Sections are digitized directly from micrographs or back-projected slides. The outlines of cells or other structures are traced from these media using a hand-held cursor on the digitizer. The positions of elements (inputs) which contact the structure and fiducials are also digitized. The sections are aligned by simultaneously displaying two consecutive sections on the graphics CRT screen. The sections are coarsely superimposed by centering around screen center using a centering algorithm. They are precisely aligned by rotating and translating the images with a reference cursor. Special functions for inserting and deleting sections and rapid section scanning are available for editing. The aligned sections are stored using a linked-list file structure on either floppy disks or tape cartridges. The rotation program replots the completed reconstructions on the graphics CRT or digital plotter. The program will reproduce the reconstructions at any scale and at any rotation in the x-, y- or z-planes. A hidden line algorithm removes hidden lines to give a 3-dimensional (3-D) perspective to the reconstructions. The positions of inputs and fiducials are represented by symbols. We use the system to reconstruct cells and neural processes. The 3-D reconstructions allow us to: (a) examine the spatial distribution and density of synaptic contacts on neurons; (b) study complex neuronal shapes; (c) examine the vectors of neural processes. The computer reconstruction system, which is moderately priced, should also prove useful for reconstructing many other types of biological profile.

Animals↗

PubMed1994

Midterm results (5.5-10 years) of acetabular allograft reconstruction with the acetabular reinforcement ring during total hip revision.

Acetabular reconstructions using frozen femoral head allografts and the acetabular reinforcement ring of M. E. Müeller (Protek AG, Bern) have been analyzed after an average follow-up period of 7.2 years (range, 5.5-10 years) in 27 patients/hips. The deficiencies, according to the American Academy of Orthopaedic Surgeons classification, were 1 segmental, 14 cavitary, and 12 combined cavity and segmental. Twenty-two (82%) of the reconstructions were classified as adequate and five (18%) as inadequate based on the operative report and radiographic assessment, including anteroposterior, oblique, and lateral views. Reconstructions were considered adequate if an appropriate sized ring had been used in accordance with the recommendations of the authors (contact on host pelvic bone cranially, posteriorly, and inferomedially). Radiographic evaluation revealed acetabular component migration of more than 2 mm in 12 reconstructions (44%). Of these, cranial migration averaged 4 mm (range, 2-9 mm) in inadequate reconstructions, whereas it averaged only 2 mm (range, 1-4 mm) in adequate reconstructions. The incidence of migration in adequate reconstructions for segmental only and combined cavitary and segmental defects was 6 of 12 (50%), whereas it was 1 of 10 in reconstructions of cavitary deficiencies. Kaplan-Meier survivorship analysis revealed a 79.6% probability of survival at 10 years with revision as the endpoint for failure. It is concluded that durability of the reconstruction can be expected if support of the metallic reinforcement device is provided by host-bone. Segmental and combined deficiencies may require additional internal fixation by plates and screws.

Acetabulum↗