Protocol and descriptive epidemiology of the SIGASCOT Italian multicentric registry of revision ACL reconstruction: a 1-year pilot study

The aim of the present study was to present the demographic and baseline results of the first year of course of the SIGASCOT Italian registry of Revision ACL reconstruction.The data of the patients undergoing revision ACL reconstruction, enrolled in by 20 SIGASCOT members from March 2015 to May 2016, were extracted from the Surgical Outcome System (SOS). Overall, 126 patients were enrolled; 18 were excluded due to incomplete data. Mean age at surgery was 30.4 ± 9.3 years (median 29; 23-38), mean BMI was 22.6 ± 2.3 kg/m2 and 77% were males. Revision was performed with a single-bundle technique in 94%, using allograft in 57% of cases and autograft in 43%. Only 28% had both menisci intact, and meniscal repair or replacement was performed in 25% of patients for medial meniscus and 8% for lateral meniscus. During the first year of enrollment, the SIGASCOT Italian ACL revision registry was able to collect the data of more than 100 patients. The revision ACL reconstruction was usually performed with a single-bundle technique, using allograft and autograft almost in the same extent.

Use and Effectiveness of the Cadaver-Lab in Orthopaedic and Traumatology Education: An Italian Survey

Purpose  The purpose of this study is to provide basic information on the availability and current use of cadaver laboratories in the education of orthopaedic residents and trainees and to determine the interest for the implementation of this type of training.

Methods  All Orthopaedic residents and trainees who attended a cadaver laboratory organized by SIGASCOT (Italian Society of the Knee, Arthroscopy, Sports Traumatology, Cartilage and Orthopaedic Technology) between 2013 and 2016 were asked to complete a survey on the availability and current use of cadaver laboratories in the education of Orthopaedic residents and trainees. The survey was sent via e-mail to 102 Orthopaedic residents and trainees. All data were analyzed and all responses are presented as counts, percentages, or means.

Results  Thirty-eight (37.2%) Orthopaedics and traumatology residents and trainees completed the survey and were included in this analysis. Eighteen trainees (18/38; 44.3%) attended a cadaver laboratory focused on lower limb surgery, whereas 20 (20/38; 52.7%) on upper limb surgery. Twenty participants (55.7%) perceived skills laboratory sessions as extremely beneficial to the understanding and becoming familiar with the normal surgical anatomy; moreover, 16 (45.7%) participants considered the cadaver laboratory extremely beneficial to the understanding of a specific surgical technique and very beneficial (44.4%) to become confident with arthroscopic or other specific surgical instruments. Over 60% of participants perceived cadaver laboratory to be very to extremely beneficial to increase confidence and speed in the operating room (OR), and more than a half of them considered skills laboratory sessions to be extremely beneficial to increase participation and decrease the occurrence of damages in the real surgical activity.

Conclusion  Orthopaedic residents and trainees found the addition of a cadaver laboratory for teaching surgical skills a significant benefit to both their overall education and surgical skills training.

Level of Evidence  Level IV, survey study.

Femoral tunnel in revision anterior cruciate ligament reconstruction

The failure rate after anterior cruciate ligament (ACL) reconstruction performed by expert surgeons is estimated to be in the range of 10-15%, and only 60% of patients undergoing this surgery are able to resume sporting activities comparable to those they engaged in prior to the traumatic incident.

Incorrect femoral tunnel placement is one of the main causes of failed ACL reconstruction and this must be remembered when undertaking revision surgery.

There are various possible errors that can be committed and, to plan revision surgery correctly, it is fundamental to study the position of the existing femoral tunnel(s) both on classic anteroposterior and lateral plain radiographs and on computed tomography scans with frontal, sagittal, and coronal sections, and also using three-dimensional reconstruction.

In-depth anatomical knowledge and familiarity with the various possible surgical techniques are also mandatory for a successful surgical outcome.

Opening wedge high tibial osteotomy using a monoaxial dynamic external fixator

PURPOSE

To prospectively assess midterm results in 37 patients (41 knees) who were treated with opening wedge high tibial osteotomy (OW-HTO) with the use of a monoaxial dynamic external fixator (MDEF) for medial knee osteoarthritis.

METHODS

Clinical and subjective evaluations were performed using the IKDC and KOOS evaluation forms and the modified Knee Society Clinical Rating System (KSS). Pin tract infections were evaluated according to Checketts-Otterburns classification. Radiographic evaluation included long-standing AP lower limb, standard lateral, Rosenberg and Merchant views.

RESULTS

Thirty-six patients (40 knees) were evaluated at a mean follow-up period of 7 years. Ten patients (25 %) developed a minor pin tract infection. Subjective KOOS and IKDC scores showed statistically significant improvement. Clinical evaluation with IKDC and KSS forms showed no patient with instability or a range-of-motion deficit worst than pre-operatively. At MDEF removal, the mechanical axis was on average 4.5° valgus; anatomical axis 6.8° valgus; the Mikulicz' line crossed the tibial plateau on average at 64 % of the width of the tibial plateau measured from medial; the posterior slope 5°; the metaphyseal varus 4.3°; and the Insall/Salvati ratio 1.02. At latest follow-up, five patients had a loss of correction of 1°-2° on mechanical axis and one patient had a loss of correction of 3° on mechanical axis and 4 % of mechanical axis on tibial plateau.

CONCLUSIONS

The use of a MDEF to perform an OW-HTO showed a good maintenance of correction achieved with satisfactory midterm outcome results in all patients but three who underwent total knee replacement. The only severe post-operative complication was one case of non-union in a heavy smoker.

LEVEL OF EVIDENCE

Prospective and therapeutic study, Level IV.

Patellofemoral function after total knee arthroplasty: gender-related differences

The purpose of the study was to evaluate patellofemoral results in 2 comparable groups of 50 patients, men and women, undergoing total knee arthroplasty. The average follow-up was 6 years. The implant was posteriorly stabilized with a dome patellar arthroplasty. The patients were studied using Knee Society knee and functional scores and the Hospital for Special Surgery (HSS) patellar score. Radiologic study included standard and weight-bearing axial views and a computed tomographic scan to assess component rotation. The 2 groups achieved satisfactory and similar knee scores; women had a significantly lower functional and patellar scores. The incidence of lateral patellar tilt, subluxation, and lateral impingement was decreased in weight-bearing axial views compared with non-weight bearing. Medial bony impingement was evident only in weight-bearing views and correlated with pain (P < .05).

Comparison between single-and double-bundle anterior cruciate ligament reconstruction: a prospective, randomized, single-blinded clinical trial

BACKGROUND

Double-bundle ACL reconstruction popularity is increasing with the aim to reproduce native ACL anatomy and improve ACL reconstruction outcome. However, to date, only a few randomized clinical studies have been published.

PURPOSE

The aim of this study was to prospectively compare the clinical results of single- and double-bundle ACL reconstruction.

STUDY DESIGN

Randomized controlled clinical trial; Level of evidence, 1.

METHODS

Seventy patients with a chronic unilateral ACL rupture who underwent arthroscopically assisted ACL reconstruction using a hamstring graft were randomized to receive a single- (SB) or double-bundle (DB) reconstruction. Both groups were comparable with regard to preoperative data. A double-incision surgical technique was adopted in both groups. The graft was fixed by looping the hamstring tendons around a bony (DB) or a metallic (SB) bridge on the tibial side and with interference screws reinforced with a staple on the femur. The same rehabilitation protocol was adopted. Outcome assessment was performed by a blinded, independent observer using the visual analog scale (VAS) score, the new International Knee Documentation Committee (IKDC) form, the Knee Injury and Osteoarthritis Outcome Score (KOOS), and KT-1000 arthrometer evaluation.

RESULTS

All the patients reached a minimum follow-up of 2 years. No differences between the 2 groups were observed in terms of KOOS and IKDC subjective score. A statistically significant difference in favor of the DB group was found with the VAS (P < .03). The objective IKDC final scores showed statistically significantly more "normal knees" in the DB group than in the SB group (P = .03). There was 1 stability failure in the DB group and 3 in the SB group. The KT-1000 arthrometer data showed a statistically significant decrease in the average anterior tibial translation in the DB group (1.2 mm DB vs 2.1 mm SB; P < .03). The incidence of a residual pivot-shift glide was 14% in DB and 26% in SB (P = .08).

CONCLUSION

In the 2-year minimum follow-up, DB ACL reconstructions showed better VAS, anterior knee laxity, and final objective IKDC scores than SB. However, longer follow-up and accurate instrumented in vivo rotational stability assessment are needed.

Conversion therapy to everolimus in renal transplant recipients: results after one year

BACKGROUND

Two new diagnoses have been causing graft loss during long-term follow-up, namely, chronic nephropathy and anticalcineurinic toxicity. The advent of the mammalian target of rapamycin (m-TOR) obviates anticalcineurine toxicity and reduces posttransplant malignancy incidence with good inmunosuppressive potential. We examinated the renal and metabolic behavior in renal transplant recipients who required conversion from an anticalcineurinic (cyclosporine or tacrolimus) to an m-TOR inhibitor (everolimus) as part of their immunosuppressive maintenance therapy.

MATERIALS AND METHODS

Twenty-one first renal transplant recipients had everolimus added to their inmunosuppressive therapy combined with an antimetabolite (mycophenolate mofetil or sodium mycophenolate). The mean age of the patients was 35 +/- 17 years (range, 6 to 65). The prevalence of male recipients was 57%; the overall mean weight, 64 kg (range, 48 to 95). All patients were hispanic with 15 transplants from cadaveric donors (71%). The mean follow-up posttransplant was 18 months (range, 3 to 40) and the mean follow-up on everolimus, 10 months (range, 2 to 22).

RESULTS

There was no mortality or graft loss, but there were 3 (17%) biopsy-confirmed acute rejection episodes. There were no significant changes in metabolic function pre- or postconversion. Regarding renal function, the mean creatinine serum showed a trend to decline: preconversion 1.7 mg/dL; postconversion 1.5 mg/dL. In 10 patients, it was possible to discontinue at least one antihypertensive medication (48%).

CONCLUSIONS

Everolimus was an effective medication to manage renal transplant patients. It produced metabolic stability and low myelotoxicity, despite combination with an antimetabolite (mycophenolic acid). Also, reduction of antihypertensive medications was an additional benefits for many patients.

Organ Donation in Latin America

Recently in Latin America, there has been a strong influence of the "Spanish model" of organ procurement. In 2001, The "Punta Cana Group" was created by Latin American transplantation coordinators with the objective of registering and improving the system of donation and procurement. In many countries there is no universal financial support from the government for medical treatment, including dialysis and transplantation. In other countries there is complete financial support for all of the population, including immunosuppressive drugs. Practically all countries have transplantation laws that follow ethical concepts, such as brain death diagnosis criteria, forms of consent, criteria of allocation, and inhibition of commerce. The rate of potential donors notified in countries that perform transplantations with deceased donors varied from 6 to 47 per million population yearly (pmp/y); The rate of effective donors varied from 1 to 20 pmp. In 2004, the mean rate of effective donors in Latin America was 5.4 pmp. The family refusal rate for the donation of organs varied from 28% in Uruguay to 70% in Peru. In some countries, such as Puerto Rico, Uruguay, and Cuba, it was more than 15 pmp, whereas in others countries deceased donors were practically not used. The number of patients on the waiting list for solid organ transplants in 12 Latin American countries is 55,000. Although the donation rate has increased by 100% during the last 10 years, it is lower than that in Europe (15 pmm/y) or the United States (20 pmp/y).

Double-bundle "anatomic" anterior cruciate ligament reconstruction: a cadaveric study of tunnel positioning with a transtibial technique

PURPOSE

The aim of this study was to examine whether a double-bundle anterior cruciate ligament (ACL) reconstruction with a transtibial approach could position the tibial and femoral tunnels accurately in the native bundle attachments.

METHODS

In 21 fresh-frozen knees the tibial and femoral attachments of the anteromedial (AM) and posterolateral (PL) bundles were outlined. The AM tibial tunnel guidewire was drilled with the 65 degree Howell tibial guide (Arthrotek, Warsaw, IN) located against the femur in the extended knee. The PL tibial wire was drilled through a prototype attachment to the Howell guide. Of the knees, 14 were available for the femoral part of the study. The AM femoral guidewire used an aimer offset 3 mm from the over-the-top position. The PL wire was drilled transtibially at 70 degrees of flexion, with external rotation and posterior drawer loads being applied. The plateaus and condyles were photographed and the wire positions measured.

RESULTS

With regard to the tibia, 17 of 21 AM wires were in the AM bundle attachment (at 61% and 36% of the natural ACL posteroanterior and mediolateral length, respectively) and 19 of 21 PL wires were in the PL bundle attachment (at 28% and 36% of the posteroanterior and mediolateral length, respectively). With regard to the femur, 12 of 14 AM wires and 9 of 14 PL wires were in the correct native bundle attachment. The AM wire was 3% more shallow than the center of the AM attachment (P = .03) and 6% more superior (P < .001), where 100% was the diameter of the posterior lateral condyle. The PL wire was 4% more shallow than the center of the PL attachment (P = .026) and 6% more superior (P < .001).

CONCLUSIONS

Anatomic and reproducible tibial guidewire positioning was achieved. Femoral wires were reproducibly positioned, but both were superior to and more shallow than the natural ACL bundle attachments, so further development or a different approach is appropriate.

CLINICAL RELEVANCE

The double-bundle reconstruction aims to restore anterior drawer and rotational stability. This technique ensures anatomic tibial positioning. Further improvements are needed with regard to the femur.

Single-and double-incision double-bundle ACL reconstruction

Double-bundle anterior cruciate ligament (ACL) reconstruction is intended to replicate the anatomy and the function of the anteromedial and posterolateral bundles of the native ACL to improve patients' satisfaction and knee stability. We prospectively assigned 75 consecutive patients with an isolated ACL lesion to one of three sequential groups of 25 patients each. Group I received a single-bundle, single-incision transtibial ACL reconstruction. Groups II and III received a double-bundle reconstruction with a single-incision transtibial technique or a double-bundle, twoincision outside-in technique, respectively. We obtained subjective International Knee Documentation Committee and Knee Injury and Osteoarthritis Outcome Score evaluations and objective International Knee Documentation Committee scores and KT-1000 measurements preoperatively and at followup. All patients reached a minimum followup of 2 years. KT side-to-side difference in Groups I, II, and III were 2.4, 1.6 and 1.4 mm, respectively. Group III had fewer patients with a positive pivot shift than Group I. The double-bundle double-incision outside-in ACL reconstruction resulted in improved anteroposterior stability and less residual pivot shift than single-incision single-bundle technique.

Femoral attachment of the anterior cruciate ligament

Endoscopic anterior cruciate ligament (ACL) reconstruction is one of the most popular orthopaedic procedures. Correct tunnel positioning is a prerequisite to success. Current surgical techniques are unable to duplicate the complex anatomy and function of the native ACL. Surgery mainly aims at restoring anteroposterior laxity. The ACL is not isometric and only a few fibers are nearly isometric over the full range of motion. However, a nearly isometric behaviour of the ACL graft is desirable. Isometry is mainly influenced by femoral attachment; thus the femoral tunnel position has a greater effect than the tibial on graft length changes. The purpose of this article is to describe the anatomy of the femoral ACL insertion and to discuss the surgical techniques used to replicate it.

Validation of the 65 degrees Howell guide for anterior cruciate ligament reconstruction

PURPOSE

To study in cadaver knees the position of the tibial tunnel in anterior cruciate ligament (ACL) reconstruction using the 65 degrees Howell guide (Arthrotek, Ontario, CA).

TYPE OF STUDY

Controlled laboratory study in vitro.

METHODS

Twenty-one fresh-frozen cadaver knees were used. The ACL was resected and its tibial attachment was demarcated. To drill the guidewire, we used the Howell 65 degrees tibial guide, which references off of the intercondylar roof in extension to avoid impingement. The intra-articular position of the wire was digitized with a digital camera and referred to a transverse axis passing through the over-the-back position and a sagittal axis passing through the lateral aspect of the medial spine. The percentage position of the wire within the ACL attachment was also calculated, taking the posterior and medial limits as the 0% positions.

RESULTS

All the wires were within the ACL attachment: 17 were in the ACL posterolateral bundle attachment and the other 4 in the anteromedial. The average distance of the wire from the transverse and sagittal axes was 12 mm (SD, 3 mm) anterior and 1 mm (SD, 1 mm) lateral, respectively. The wire was positioned at 38% (SD, 16%) of the length of the ACL attachment and at 40% (SD, 17%) of the width. Eighty percent of the wires were positioned at between 35% and 48% of the attachment length.

CONCLUSIONS

The 65 degrees Howell guide, which positions the tibial tunnel in extension to avoid roof impingement, ensures anatomic positioning of the graft on the tibial side and reproducibility can be expected.

CLINICAL RELEVANCE

This study proves that a commonly used drill guide succeeds in placing the ACL graft in the tibial anatomic attachment.

Anterior cruciate ligament reconstruction with double-looped semitendinosus and gracilis tendon graft directly fixed to cortical bone: 5-year results

Forty-three patients who had undergone an anterior cruciate ligament (ACL) reconstruction using a doubled semitendinosus and gracilis graft were prospectively reviewed at 5-year follow-up. All had suffered subacute or chronic tears of the ligament. At surgery, the femoral tunnel was drilled first through the antero-medial portal. The correct position of the femoral and tibial guide wire was checked fluoroscopically. A cortical fixation to the bone was achieved in the femur with a Mitek anchor, directly passing the two tendons in the slot of the anchor, and in the tibia with an RCI screw, supplemented with a spiked washer and bicortical screw. Rehabilitation was aggressive, controlled and without braces. The International Knee Documentation Committee (IKDC) form, KT-1000 arthrometer, and Cybex dynamometer were employed for clinical evaluation. A radiographic study was also performed. At the 5-year follow-up all the patients had recovered full range of motion and 2% of them complained of pain during light sports activities. Four patients (9.5%) reported giving-way symptoms. The KT-1000 side-to-side difference was on average 2.1 mm at 30 lb, and 68% of the knees were within 2 mm. The final IKDC score showed 90% satisfactory results. There was no difference between the 2-year and 5-year evaluations in terms of stability. Extensor and flexor muscle strength recovery was almost complete (maximum deficit 5%). Radiographic study showed a tunnel widening in 32% of the femurs and 40% of the tibias. A correlation was found between the incidence of tibial tunnel widening and the distance of the RCI screw from the joint (the closer the screw to the joint, the lower the incidence of widening). In conclusion, we can state that, using a four-strand hamstring graft and a cortical fixation at both ends, we were able to achieve satisfactory 5-year results in 90% of the patients.

Anterior cruciate ligament reconstruction: bone-patellar tendon-bone compared with double semitendinosus and gracilis tendon grafts. A prospective, randomized clinical trial

BACKGROUND

The choice of graft for anterior cruciate ligament reconstruction is a matter of debate, with patellar and hamstring tendons being the two most popular autologous graft options. The objective of this study was to determine in a prospective, randomized clinical trial whether two grafts (bone-patellar tendon-bone or doubled hamstring tendons) fixed with modern devices affect the two-year minimum clinical and radiographic outcomes of anterior cruciate ligament reconstruction.

METHODS

One hundred and twenty patients with a chronic unilateral rupture of the anterior cruciate ligament underwent arthroscopically assisted reconstruction with use of either autologous bone-patellar tendon-bone or doubled hamstring tendon grafts, in a strictly alternating manner. Both groups were comparable with regard to demographic data, preoperative activity level, mechanism of injury, interval between the injury and the operation, and the amount of knee laxity present preoperatively. The same well-proven surgical technique and aggressive controlled rehabilitation was used. An independent observer, who was blinded with regard to the involved leg and the type of graft, performed the outcome assessment with use of a visual analog scale, the new International Knee Documentation Committee form, the Knee Injury and Osteoarthritis Outcome Score, the Functional Knee Score for Anterior Knee Pain, and an arthrometric and an isokinetic dynamometric evaluation. Radiographs were also made.

RESULTS

At the two-year follow-up evaluation, no differences were found in terms of the visual analog score, the Knee Injury and Osteoarthritis Outcome Score, the new International Knee Documentation Committee subjective and objective evaluation scores, the KT-1000 side-to-side laxity measurements, the Functional Knee Score for Anterior Knee Pain, muscle strength recovery, or return to sports activities. In the bone-patellar tendon-bone group, we found a higher prevalence of postoperative kneeling discomfort (p < 0.01) and an increased area of decreased skin sensitivity (p < 0.001). In the hamstring tendon group, we recorded a higher prevalence of femoral tunnel widening (p < 0.01). In this group, a correlation was also found between medial meniscectomy and an increased prevalence of pivot-shift glide (p = 0.035).

CONCLUSIONS

We believe that, with use of accurate and proven surgical and rehabilitation techniques, both grafts are an equivalent option for anterior cruciate ligament reconstruction.

Lateral collateral ligament reconstruction using a semitendinosus graft

We evaluated 13 reconstructions of the lateral collateral ligament (LCL) of the knee associated with a reconstruction of the ACL (n=6) and PCL (n=7). In all cases the LCL was reconstructed using a semitendinosus tendon graft through a tunnel in the fibular head and fixed in anatomical insertion of LCL at lateral femoral condyle. Patients were evaluated using the IKDC form. Lateral joint opening and posterior tibial translation were studied by radiographic stress views. The follow-up average was of 60 months (38-93). In the ACL group five patient were symptoms free while one reported moderate pain after strenuous activity. The lateral stress radiographs showed lateral joint opening of 0-2 mm in five knees, and 3-5 mm in one. In the PCL group four patients were symptom free while three complained mild to moderate pain or swelling. Lateral joint opening was 0-2 mm in six knees and 3-5 in one. External rotation at 30 degrees of flexion was 10 degrees in one and between 0-5 degrees in the remainder. Eleven of 13 patients returned to their preinjury level and two returned to one level lower. These findings indicate that the LCL can be successfully reconstructed with a free ST graft at the time of ACL or PCL reconstruction.

Could X-ray microbeams inhibit angioplasty-induced restenosis in the rat carotid artery?

BACKGROUND

Parallel, thin (<100 microm) planes of synchrotron-generated X rays, have been shown to spare normal tissues and preferentially damage tumors in animal models. The aim of the present study was to assess the effect of such microbeams directed unidirectionally on angioplasted rat carotid arteries.

METHODS AND MATERIALS

Three groups of Sprague-Dawley rats were studied: (a) rats with normal, untreated arteries, (b) rats treated by balloon angioplasty, but not irradiated, and (c) rats treated with balloon angioplasty and exposed to single fraction, unidirectional, parallel, microbeams an hour after angioplasty. The microbeam array, 15 mm widex7.6 mm high, consisting of 27-microm-wide beam slices, spaced 200 microm center-to-center laterally traversed the damaged artery. The in-depth in-beam dose was 150 Gy, the "valley" dose (dose midway between microbeams resulting mainly from X-ray scattering) was 4.5 Gy on average, and the "integrated" (averaged) dose was 26 Gy.

RESULTS

Microbeam irradiation, as given in the present study, was tolerated, but was insufficient to significantly suppress the neointimal hyperplasia.

DISCUSSION

The microbeam dose used is considered low. Dose escalation would be necessary to reach conclusive results regarding the X-ray microbeam efficacy to control restenosis.

Biologic resurfacing of the patella: current status

The techniques of biologic resurfacing of the patella, like other joint surfaces, are still evolving. Currently none of them is free from criticism. In this regard it is our hope that progress in the basic science will offer in the near future new and more optimistic therapeutic possibilities (i.e., the restoration of a reparative cartilage that is structurally and functionally comparable to the native one). The greater expectancies come perhaps from the present experimental investigations about the combined use of tissue-engineered implants embedded with staminal cells and growth factors. Many problems remain to be solved, however, before reliable applicability in humans. From a general point of view, stem cells obtained from various sources (e.g., adult bone marrow, umbilical cord) offer the same finalities as the embryonic stem cells, without the ethical obstacles related to the latter. Therefore, it may be that restoration of part or all of the articular surface of a joint will be possible by way of these mesenchymal progenitors that have the ability to differentiate into the chondrogenic and osteogenic lines, which is required for the restoration of the various layers of a normal articular cartilage and subchondral bone.

Limb salvage using high-pressure intermittent compression arterial assist device in cases unsuitable for surgical revascularization

HYPOTHESIS

Intermittent compression therapy for patients with inoperable chronic critical ischemia with rest pain or tissue loss may have beneficial clinical and hemodynamic effects.

STUDY DESIGN

Case series of 14 consecutive ischemic legs that underwent application of a 3-month treatment protocol during a 2(1/2)-year study.

SETTING

Veterans Administration Hospital.

PATIENTS

Thirteen patients with 14 critically ischemic legs (rest pain, n = 14; tissue loss, n = 13) who were not candidates for surgical reconstruction were treated with rapid high-pressure intermittent compression. The patients had a mean age of 76.2 years, 8 were diabetic, and they represented 10% of referrals for chronic critical ischemia. They were not amenable to revascularization owing to lack of outflow arteries (n = 7), lack of autogenous vein (n = 5), or poor general medical condition (n = 3).

INTERVENTION

All patients were instructed to use the arterial assist device for 4 hours a day at home for a 3-month period.

MAIN OUTCOME MEASURES

Limb salvage and calibrated pulse volume amplitude.

RESULTS

After 3 months, 9 legs had a significant increase in pulse-volume amplitude (P< .05). These legs were salvaged, whereas the 4 amputated legs demonstrated no hemodynamic improvement. We noted a direct correlation between patient compliance and clinical outcome. Patients in whom limb salvage was achieved used their compression device for longer periods of time (mean time, 2.38 hours a day) compared with those who underwent amputation (mean time, 1.14 hours a day) (P< .05). These mean hours of use were derived from an hour counter built into the compression units.

CONCLUSIONS

Intermittent high-pressure compression may allow limb salvage in patients with limb-threatening ischemia who are not candidates for revascularization. Further studies are warranted to assess intermittent compression as an alternative to amputation in an increasingly older patient population.

Results of arthroscopic excision of the fragment in the treatment of osteochondritis dissecans of the knee

PURPOSE

To evaluate clinical and radiological results of arthroscopic excision of the fragment and debridement of the crater in the treatment of osteochondritis dissecans of the knee (OCD).

TYPE OF STUDY

Case series.

METHODS

We investigated 20 patients with partial or complete detachment of the OCD fragment. The average age at surgery was 21 years (range, 12 to 32 years). All the patients were treated by the same surgeon. They were evaluated at an average follow-up of 9 years (range, 6 to 17 years).

RESULTS

The combined subjective and objective evaluation showed excellent and good results for 85% of the patients. Radiographic studies showed 2 grades of worsening (from no degenerative signs preoperatively to narrowing of the joint line up to 50% at follow-up) in 1 patient (5%). One grade of worsening (Fairbank's changes without joint space narrowing) was found in 45% of weight-bearing anteroposterior radiographic views and in 35% of weight-bearing bent knee posteroanterior views. Statistical correlations were significant between radiographic degenerative changes and the size of the osteochondral lesion at surgery, with larger lesions resulting in greater degenerative changes.

CONCLUSIONS

The arthroscopic removal of an osteochondral fragment and debridement of the crater is a viable option in the treatment of grade III and IV OCD lesions. Results are better in lesions less than 2 cm(2).

Coronary and carotid operations under prospective standardized conditions: incidence and outcome

BACKGROUND

No randomized trial has yet evaluated the hypothetical benefit of carotid endarterectomy with coronary artery bypass grafting. This prospective review was undertaken to determine the differences between observed and predicted complication rates, as well as to define new predictors and assess costs in a standardized population.

METHODS

A prospective nonrandomized study was undertaken over a 4-year period involving all coronary artery bypass graftings done at one institution. Operative procedure was standardized. All patients underwent preoperative screening for carotid disease. If 80% or more stenosis was present, combined coronary artery bypass grafting and carotid endarterectomy was performed.

RESULTS

Of 2,071 patients, 1,987 had coronary artery bypass grafting only. In that group there were 34 strokes (1.7%) and 41 deaths (2.0%). Eighty-four patients underwent combined coronary artery bypass grafting/carotid endarterectomy and in that group there were four strokes (4.7%) and five deaths (5.9%). Independent risk factors for postoperative stroke were age (odds ratio 1.09; 95% confidence interval 1.04, 1.3), hypertension (odds ratio 2.67; 95% confidence interval 1.22, 5.23), extensively calcified aorta (odds ratio 2.82; 95% confidence interval 1.34, 5.97), and bypass time (odds ratio 1.01; 95% confidence interval 1.00, 1.02). Cost of a stroke was significant (p < 0.05) in both groups.

CONCLUSIONS

Patients with carotid disease fall into a higher risk group than patients without it. This increased risk is not because of carotid disease alone. Patients without significant carotid disease, who suffered a perioperative stroke, fell into an even higher risk category. Furthermore, carotid endarterectomy was not a significant risk factor by either the univariate or the multivariate analysis.

Tuberculous pseudoaneurysm of the descending thoracic aorta: successful treatment by surgical excision and primary repair

Tuberculous pseudoaneurysm of the aorta is a rare disease with a high mortality rate. We present the case of a 27-year-old woman who had a tuberculous pseudoaneurysm of the descending thoracic aorta. The patient underwent successful excision and primary repair of the lesion while under hypothermic circulatory arrest and partial femoral bypass. To the best of our knowledge, this is the youngest patient to be successfully treated with surgery for a tuberculous pseudoaneurysm of the descending thoracic aorta. The pathogenesis, diagnosis, and treatment of this disease are reviewed, and the need to include tuberculous pseudoaneurysm in the differential diagnosis of chest lesions is emphasized.

Femoral tunnel position in anterior cruciate ligament reconstruction using three techniques. A cadaver study

The possibility of achieving correct deep femoral tunnel positioning during anterior cruciate ligament (ACL) reconstruction with the double incision technique (DI), the transtibial technique (TT), and the anteromedial technique (AM) was evaluated in 30 cadaver knees. A reference hole was made just deep to the insertion of the anteromedial bundle of the ACL through an anteromedial arthrotomy. In the DI technique, a Kirshner wire was inserted outside-in using a rear entry C guide. In the TT and AM techniques, the K-wire was inserted inside-out through the tibial tunnel and through the arthrotomy, respectively. The reference hole could be achieved with each technique. Using lateral radiographs, the superficial aspect of the intra-articular exit of the femoral tunnel was found to be located on average at 36%, 36%, and 34% of the width of the condyles from the posterior margin (NS). None of the holes was more anterior than 40%. In conclusion, a deep femoral tunnel positioning could be achieved with each technique. The choice of technique must be based on the surgeon's preference and clinical results.

The relationship between the intercondylar roof and the tibial plateau with the knee in extension: relevance for tibial tunnel placement in anterior cruciate ligament reconstruction

The relationship between the intercondylar roof and the tibial plateau with the knee in full extension was studied in 100 patients with a unilateral anterior cruciate ligament (ACL) lesion. A lateral view of both knees in full extension with superimposition of the femoral condyles was obtained with the fluoroscope. We found that, in the normal knee, the roof line intersects the tibial plateau (roof-plateau intersection ratio) at 31.5% (SD +/- 5%) of its width and at 33.9% (+/- 5.4%) in the ACL deficient knee (P < .001). The difference was attributable to a subtle anterior tibial displacement in the ACL-deficient knee. Multiple regression analysis showed a direct relationship between roof-plateau intersection ratio and the angle between roof line and tibial plateau (P = .0006). A direct relationship of borderline significance (P = .06) was present with the knee recurvatum measured clinically. In conclusion, the roof-plateau intersection ratio has a wide range of variability (22% to 41%). The larger the roof-plateau angle the more posterior the roof-plateau intersection ratio.

The Insall-Burstein total knee replacement in osteoarthritis: a 10-year minimum follow-up

A total of 99 Insall-Burstein posterior stabilized (IBPS) knee replacements were implanted in 86 osteoarthritic patients. We reviewed 60 knees with a 10- to 15-year follow-up. Using the Knee Society score, 35 knees (58%) were excellent, 15 (25%) good, 4 (7%) fair, and 6 (10%) poor. Flexion at follow-up was 106 degrees on average. Moderate patellofemoral crepitation was present in 5 knees (9%), and 11 knee required excision of a synovial nodule proximal to the patella. Radiographic analysis showed 5 osteolytic lesions (8%) around well-fixed tibial and femoral components and minimal (1 mm) narrowing of the medial polyethylene thickness in 7 knees (12%). There were 6 (10%) failures requiring reoperation because of aseptic loosening (4 knees), deep infection (1 knee), and recurrent patellar dislocation (1 knee). Survivorship analysis using revision as the endpoint showed a cumulative success rate of 92% at 10 years. In this study, the IBPS knee has shown good long-term results with low rates of aseptic loosening and no failures attributable to polyethylene wear.

Bilateral subclavian artery aneurysms with pseudocoarctation of the aorta. Case report and review of the literature

Subclavian artery aneurysms are rare. They occur predominantly on the right side. The most frequent cause of proximal subclavian artery aneurysm is atherosclerosis. An aneurysm of the left subclavian artery with normal origin is less common, and it is extremely rare when associated with an aortic coarctation. This report describes the first case of bilateral subclavian artery aneurysms associated with a pseudocoarctation of the aorta. Successful resection of the left subclavian artery aneurysms and the pseudocoarctation of the aorta was achieved using partial cardiopulmonary bypass.

Arthroscopic-assisted anterior cruciate ligament reconstruction with the central third patellar tendon. A 5-8-year follow-up

We reviewed 89 arthroscopically assisted patellar tendon anterior cruciate ligament (ACL) reconstructions for chronic isolated injuries with an average follow-up of 7 years (range 5.4 to 8.6 years). Pain was present in 7 knees (8%). Giving-way symptoms were reported by 7 patients (8%). A KT-2000 side-to-side difference over 5 mm at 30 lbs was recorded in 12 cases (16%). The pivot shift was glide in 17 cases (19%) and clunk in 10 (11%). A 3 degrees-5 degrees extension loss compared with the normal side was present in 20 knees (22%) and 6 degrees-10 degrees in 4 knees (4%). The intra-articular exit of the femoral tunnel was misplaced in the anterior 50% of the condyles along the roof of the notch in 10% of the knees. This positioning significantly (P = 0.003) increased the frequency of graft failure (62.5%) compared with the cases with a more posterior placement (graft failure 12%). An anterior position of the intra-articular exit of the tibial tunnel (in the anterior 15% of the sagittal width of the tibia) significantly (P = 0.01) increased the frequency of extension loss > 5 degrees. Medial meniscectomy was associated with a 35% incidence of narrowing of the medial joint space, which was significantly higher compared with knees with normal menisci (9%; P = 0.04) or with medial meniscal repair (7%; P = 0.05). In conclusion this study showed satisfactory anterior stability (KT-2000 side-to-side difference up to 5 mm and pivot absent or glide) in 83% of the knees. This percentage increases to 88% in the knees with a correct posterior and proximal femoral tunnel placement. Accuracy in tunnel positioning is essential for the success of ACL surgery. Meniscal repair was effective in decreasing joint space narrowing and should be attempted when possible.

Single-and dual-energy CT with monochromatic synchrotron x-rays

We explored the potential for clinical research of computed tomography (CT) with monochromatic x-rays using the preclinical multiple energy computed tomography (MECT) system at the National Synchrotron Light Source. MECT has a fixed, horizontal fan beam with a subject apparatus rotating about a vertical axis; it will be used for imaging the human head and neck. Two CdWO4-photodiode array detectors with different spatial resolutions were used. A 10.5 cm diameter acrylic phantom was imaged with MECT at 43 keV and with a conventional CT (CCT) at 80 kVp: spatial resolution approximately equal to 6.5 line pairs (lp)/cm for both; slice height, 2.6 mm for MECT against 3.0 mm for CCT; surface dose, 3.1 cGy for MECT against 2.0 cGy for CCT. The resultant image noise was 1.5 HU for MECT against 3 HU for CCT. Computer simulations of the same images with more precisely matched spatial resolution, slice height and dose indicated an image-noise ratio of 1.4:1.0 for CCT against MECT. A 13.5 cm diameter acrylic phantom imaged with MECT at approximately 0.1 keV above the iodine K edge and with CCT showed, for a 240 micrograms I ml-1 solution, an image contrast of 26 HU for MECT and 13 and 9 HU for the 80 and 100 kVp CCT, respectively. The corresponding numbers from computer simulation of the same images were 26, 12, and 9 HU, respectively. MECT's potential for use in clinical research is discussed.

[Diseases of the pericardium in Avenzoar's Kitab al-Taysir (c.1095-1162)]

Avenzoar has been credited as the author of the first description of inflammation of the pericardium in medical historical literature. Our study shows that although Avenzoar authored a study of diseases of the pericardium with emphasis on pathologies, his epistemological framework was similar to that used by Galen and Avicenna, authors who constituted the source of knowledge for Islamic medicine. We show that the approach used by Avenzoar appears to derive from the absence of anatomical and physiological information, and from a detailed description of the indications and treatments, which distinguish his work from earlier writings.

Arthroscopically assisted semitendinosus and gracilis tendon graft in reconstruction for acute anterior cruciate ligament injuries in athletes

We evaluated 69 arthroscopically assisted anterior cruciate ligament reconstructions for acute tears at an average followup of 60 months. We used a distally based single semitendinosus and gracilis tendon graft passed over the top and fixed to the femur. Combined medial collateral ligament lesions were seen in 30 knees, and they were repaired when found in the distal third (18 knees). The patients were instructed to recover motion preoperatively, and an early range of motion program was used postoperatively. At followup, symptoms of giving way were seen in five knees (7%). Graft failure was seen in seven knees (10%); failure was defined as a positive pivot shift (clunk or gross) or a side-to-side difference in anterior tibial displacement greater than 5 mm, as measured with a KT-1000 arthrometer. Permanent extension loss (3 degrees to 5 degrees) was found in two knees (3%). Patellofemoral crepitation was seen in eight knees (12%), but the condition was symptomatic in only one knee. Forty-six patients (67%) were active in pivoting sports before surgery and 37 (54%) remained active in these sports at followup. We concluded that this operation is simple, effective, and has a low complication rate. Further studies are necessary to elucidate if a stronger graft (e.g., a patellar tendon) would decrease the rate of graft failure without increasing complications.

Intravenous leiomyomatosis

Intravenous leiomyomatosis is a rare tumor in which benign smooth muscle cells grow into the pelvic venous channels of female patients. A case of intravenous leiomyomatosis with cardiac extension in a 45-year-old woman is described. The patient was diagnosed with cardiac syncope 3 months after total abdominal hysterectomy and was successfully treated with a two-stage approach consisting of sternotomy followed by laparotomy. The cause, disease, presentation, diagnosis, treatment and recurrence are reviewed.

Surgical treatment of recurrent dislocation of the patella

Sixty-seven patients (69 knees) with recurrent patellar dislocation underwent either a lateral release (20 knees), a proximal realignment (14 knees), a distal realignment (16 knees), or a combined realignment (19 knees) procedure. Average respective followup was 8, 8, 6, and 4 years. Patients undergoing lateral release experienced a 40% recurrence of patellar dislocation. After a realignment procedure, redislocation was uncommon (4%), but pain and swelling were reported by 12% of the patients. Significant patellofemoral crepitation was present in 35% of the realignments. The congruence angle was corrected satisfactorily in the proximal realignments, but it remained abnormal in 25% of the distal realignments. The distance from the tuberosity to the sulcus was restored to normal by transposition of the tibial tuberosity, but remained abnormal in 36% of the proximal realignments. However, it did not preclude a good clinical result. Lateral release cannot be recommended for knees with severe dysplasia of the extensor mechanism. Proximal, distal, and combined realignments yielded similar clinical results. Retensioning of the medial structures and lateral release are effective in reducing the patella within the sulcus. Although transposition of the tuberosity is appealing, clinical advantages are less evident.

After the blue toe: prognosis of noncardiac arterial embolization in the lower extremities

PURPOSE

To better understand the prognosis of atheroembolic disease, we reviewed the outcomes of 41 patients with embolization to the viscera and lower extremities.

METHODS AND RESULTS

All cases involved emboli that originated from a radiographically identified proximal arterial source. There were 30 men and 11 women (mean age 65 years; mean follow-up time 2 years), and all had been first treated for this condition within the past 6 years. The overall mortality rate was 17% (7/41) and the rate of recurrent embolization 15% (6/41). To compare outcomes associated with supradiaphragmatic versus subdiaphragmatic disease, we defined two groups: group 1 comprised patients (n = 5) in whom the identified embolic source extended above the diaphragm, and group 2 comprised patients (n = 36) in whom the source remained below the diaphragm. The mortality rates in groups 1 and 2 were 60% (3/5) and 11% (4/36), respectively (p < 0.05). Recurrent embolization was also significantly higher in group 1 (60% vs 8%, p < 0.025). There were two amputations in group 1 and six in group 2 (p = not significant). Group 2 patients were then divided into two subgroups: those with limited disease (n = 19) in which the emboli had a single, radiographically identified source (i.e., aneurysm or single area of ulcerated plaque) and those with diffuse disease (n = 17) in which the emboli had multiple, radiographically identified potential sources. In the subgroup of patients with limited disease, no deaths or episodes of recurrent embolization occurred, whereas four deaths and three episodes of recurrent embolization occurred in the subgroup of patients with diffuse disease. The differences in these outcomes, however, were not statistically significant. Thirty selected patients (one from group 1 and 29 from group 2) underwent operation on or bypass of the imputed lesion. Only one (7%) of these 30 patients had recurrent embolization. In contrast, recurrent embolization was noted in four (36%) of the 11 patients who did not have an operation directed at the lesion (p < 0.025). No significant difference in mortality was found between patients who underwent operation and those who did not.

CONCLUSIONS

Patients with atheroemboli have a substantial mortality rate and risk of recurrent embolization, especially if the disease process extends above the diaphragm; but in selected patients, operation may decrease the frequency of recurrence without increasing mortality.

Wound complications of the retroperitoneal approach to the aorta and iliac vessels

Repeated complaints of postoperative wound pain prompted this review of 113 consecutive vascular operations involving a retroperitoneal approach to the aorta or iliac vessels or both. Flank muscle-splitting incisions (n = 53) had been used to approach the terminal aorta or iliac arteries. Two types of muscle-dividing incisions had also been used: incisions through the eleventh intercostal space (n = 41) to approach the infrarenal aorta; and incisions through the eighth, ninth, or tenth intercostal space with division of the diaphragm (n = 19) to approach the suprarenal aorta. Data on incisional pain, lumbosacral neuritic pain, incisional hernia, and deforming abdominal bulge were culled from the records of follow-up examinations conducted on all patients during periods ranging from 2 to 48 months. Both types of muscle-dividing incisions used to expose the aorta were associated with a 23% (14/60) incidence of abdominal bulge, a 7% (4/60) incidence of incisional hernia, and, more important, a 37% (22/60) incidence of prolonged disabling pain. Thus, although retroperitoneal exposure may be the preferred or the safest approach to certain aortic lesions, its routine use via muscle-dividing incisions is not recommended when the proposed operation can be carried out equally well by the conventional midline transperitoneal approach.

The retroperitoneal approach to aortic surgery associated with horseshoe kidney

The horseshoe kidney is a rare anomaly that can significantly complicate aortic surgery. A bulky isthmus, abnormalities of renal anatomy, and a variable blood supply associated with a horseshoe kidney can pose technical difficulties in terms of aortic reconstruction. The left retroperitoneal approach affords an excellent exposure of the abdominal aorta in patients with a horseshoe kidney without dividing the renal isthmus and avoids the risk of injury to a ureter in an anomalous location. This is a case report of a patient with a horseshoe kidney who underwent a successful repair of an abdominal aortic aneurysm by a left retroperitoneal approach.

Complications of percutaneous intra-aortic balloon pump use in patients with peripheral vascular disease

Percutaneous intra-aortic balloon pump use may carry an increased risk for patients with peripheral vascular disease. To determine the incidence and types of associated complications, the medical records of 144 patients who underwent a total of 153 percutaneous intra-aortic balloon pump insertions were reviewed. Patients were divided into two groups. Group 1 was composed of 20 patients with a history of peripheral vascular disease. Group 2 was composed of 124 patients without such history; they underwent a total of 133 insertions. Nineteen major complications (12%) occurred, 12 in group 1 (60% of 20 insertions) and seven in group 2 (5% of 133 insertions). Major complications were further classified by their nature: embolic, occlusive, and technical. All three types of complications occurred more frequently in group 1. Embolic complications occurred more frequently in patients with aneurysms and proved the most lethal, with two of six deaths in group 1 resulting from this complication.

Indirect measurement of systolic blood pressure in the rabbit

Long-term studies of rabbit blood pressure require a reliable method for repeated blood pressure measurements. Ideally, this method would be simple, noninvasive, and accurate over the range of anticipated blood pressures. To facilitate our own studies of rabbit carotid artery graft patency, we have developed a technique for the indirect measurement of systolic blood pressure in the rabbit that utilizes a photoplethysmograph sensor placed distal to an inflatable air bladder positioned over the central ear artery. We have compared measurements obtained with this method to direct measurements of aortic pressure and found a linear correlation.

Mesenteric blood flow in patients with diabetic neuropathy

We examined flow velocities in the superior mesenteric artery and celiac artery in normal controls (group C, n = 11), diabetic patients (group D, n = 8), and diabetic patients with clinically evident autonomic neuropathy (group DN, n = 6) to further define the usefulness of duplex examination in the evaluation of the mesenteric circulation in normal and disease states. By use of a 3 MHz duplex scanner, peak systolic velocity, peak diastolic forward velocity, end-diastolic forward velocity, and peak diastolic reverse velocity were measured in centimeters per second before and after a standardized meal. The vessels' diameters in centimeters were also measured. After the meal peak diastolic reverse velocity disappeared in all patients. The average vessel diameter in the superior mesenteric artery (0.7 cm) and celiac artery (0.8 cm) did not change. Flow velocities in the celiac artery were not significantly altered by the meal. In the control group, peak systolic velocity in the superior mesenteric artery increased 38%, peak diastolic forward velocity rose 66%, and end-diastolic forward velocity increased by 70%. In the diabetic nonneuropathic group the changes were 15%, 98%, and 100%, respectively. These changes were statistically significant (p less than 0.01). On the other hand, the patients with diabetic autonomic neuropathy presenting a picture of gastroparesis did not exhibit the expected increases in postprandial velocities. Moreover, this alteration in blood flow velocity, although similar to that encountered in patients with intestinal angina, did not appear to be due to occlusive arterial disease on the basis of clinical examination and B-mode scanning.

Transaortic endarterectomy of renal visceral artery lesions in association with infrarenal aortic surgery

The complexity of infrarenal aortic reconstruction increases when bypass grafts to revascularize associated renal and visceral arteries are needed. Lesions in these vessels, however, are usually limited to their aortic orifices and therefore are amenable to retroperitoneal transaortic endarterectomy. A combined infrarenal aortic reconstruction and transaortic endarterectomy of the renal/visceral vessels was used in 18 (16%) of 120 patients undergoing elective infrarenal aortic reconstruction over a 2-year-period. Transaortic endarterectomy was performed primarily for renal preservation in 11 patients with bilateral, high-grade renal artery stenoses and abnormal renal function (serum creatinine greater than or equal to 1.9 mg/dl). In seven patients transaortic endarterectomy was performed as a secondary procedure during the course of complex reconstruction of aneurysmal or occlusive aortic disease. Mean serum creatinine, which was elevated preoperatively in 14 (78%) patients (3.3 mg/dl), decreased significantly after the operation (2.0 mg/dl, p less than 0.01). A single death occurred in the 18 patients undergoing transaortic endarterectomy. Renal function preservation can be achieved by renal revascularization in patients with bilateral renal artery stenoses and decreased renal function. The retroperitoneal approach to aortic reconstruction and the use of transaortic endarterectomy allows correction of most renal/visceral vessel involvement in complex aortic revascularization procedures.

Combined epidural and general anesthesia in aortic surgery

The perioperative course of 144 consecutive patients undergoing aortic reconstructive surgery was studied to assess the potential benefit of employing a combined epidural and light general anesthesia technique. A group of 67 patients had general anesthesia alone (GA), while in the group of 77 remaining patients, a combined epidural and general anesthesia (Epi-GA) was employed. The two groups were similar in regards to age, medical risk factors, preoperative assessment of cardiac and pulmonary function, and type of surgical reconstruction. There was no significant difference in the anesthetic, operative time, or operative fluid requirements between the two groups. There was a lower rate pressure product in the Epi-GA group during aortic cross clamping (P less than 0.05). More patients in the GA group required a prolonged ventilatory support (P less than 0.05) and a high parenteral narcotic administration (P less than 0.025) during the first 48 hours. While the mortality rate was similar for the two groups (3.0% for GA group vs 5.2% for Epi-GA group), there was a higher percent of postoperative pulmonary complications observed in the GA group (7.6%) compared to the Epi-GA group (2.6%). By facilitating early extubation and a decreased need for systemic narcotics in the early postoperative period, Epi-GA may be beneficial in the high risk pulmonary patient undergoing aortic reconstruction.

The value of computed tomography in the management of symptomatic abdominal aortic aneurysms

The use of computed tomographic (CT) scanning in the diagnosis of ruptured abdominal aortic aneurysm is controversial because the delay created by the procedure, it has been argued, may increase overall mortality. However, if emergency surgery can be avoided in the medically compromised patient, surgical results may improve. To assess the value of CT scanning, we studied the 1983 to 1988 records of 65 hemodynamically stable patients with abdominal aortic aneurysms, who underwent diagnostic CT scanning for acute abdominal or back pain. Twenty-one patients had a history of severe cardiac, renal, or pulmonary disease. The average duration of the examination was 63 minutes; no episodes of hypotension occurred. Subsequently, 17 of 18 patients with ruptured aneurysms had emergency surgery, with 31% morbidity and 29% mortality. Of 44 patients found to have nonruptured aneurysms, 13 had other causes for their pain, nine were not considered surgical candidates, and 24 had elective aneurysmectomies, with 8% morbidity and 0% mortality. In three patients CT scanning excluded the diagnosis of aneurysm. Additional information provided by CT scanning enhanced the safety of the perioperative management of four patients with rupture and 14 without. In conclusion, the delay imposed by obtaining a preoperative CT scan in patients with possible ruptured aneurysm did not adversely affect patient outcome, and the information obtained from it aided significantly in both preoperative and intraoperative management.

The early and late responses of the arterial wall to graft placement

The relationship between the early smooth muscle cell proliferative response (SMC-PR) to injury and the later development of myointimal hyperplasia (MIH) complicating arterial bypass grafts remains unclear. In the present study, the early SMC-PR and the later MIH induced by a 2-mm-diameter PTFE graft placed in a rabbit carotid were compared with the response induced by an autogenous artery (AA) graft in the contralateral carotid. The early SMC-PR was measured in the proximal and distal arterial segments 5 days after graft placement by in vivo labeling with [3H]thymidine to determine the DNA specific activity (DNA-SA). The later anastomotic MIH was measured 16 and 32 weeks postgrafting by calculating the intimal/medial ratio. There was a marked and similar increase in the early SMC-PR noted with both the AA and the polytetrafluoroethylene (PTFE) grafts. The distal segments demonstrated a significantly higher DNA-SA when compared to the proximal in both AA- and PTFE-grafted arteries. There was a moderate degree of anastomotic MIH noted in chronic grafts; however, a regression in intimal thickening was observed over time in the AA-grafted arteries, while the distal anastomosis of the PTFE-grafted vessels demonstrated a continuous progression of the MIH process. The early SMC-PR may abate in arteries grafted with autogenous grafts, but there is a persistent proliferative response at the distal anastomosis associated with synthetic grafts.

Energetic behaviour of mitochondria isolated from rat livers perfused with a perfluorodecalin + N,N-perfluorodiethylcyclohexylamine emulsion

Rat livers have been perfused with a saline control medium or with a perfluorocarbon emulsion containing perfluorodecalin and N,N-perfluorodiethylcyclohexylamine, and the respiratory rates and transmembrane electrical potentials of mitochondria isolated following perfusion have been evaluated. The results indicate that the perfluorocarbon emulsion used, by providing a good oxygen supply to the perfused liver, allowed to preserve the efficiency of mitochondrial oxidative phosphorylation.