Biomechanical comparison of the four-strand cruciate and Strickland techniques in animal tendons

OBJECTIVE

The objective of this study was to compare two four-strand techniques: the traditional Strickland and cruciate techniques.

METHODS

Thirty-eight Achilles tendons were removed from 19 rabbits and were assigned to two groups based on suture technique (Group 1, Strickland suture; Group 2, cruciate repair). The sutured tendons were subjected to constant progressive distraction using a universal testing machine (Kratos®). Based on data from the instrument, which were synchronized with the visualized gap at the suture site and at the time of suture rupture, the following data were obtained: maximum load to rupture, maximum deformation or gap, time elapsed until failure, and stiffness.

RESULTS

In the statistical analysis, the data were parametric and unpaired, and by Kolmogorov-Smirnov test, the sample distribution was normal. By Student's t-test, there was no significant difference in any of the data: the cruciate repair sutures had slightly better mean stiffness, and the Strickland sutures had longer time-elapsed suture ruptures and higher average maximum deformation.

CONCLUSIONS

The cruciate and Strickland techniques for flexor tendon sutures have similar mechanical characteristics in vitro.

Comparative study related to cardiovascular safety between bupivacaine (S75-R25) and ropivacaine in brachial plexus block

BACKGROUND AND OBJECTIVES

Bupivacaine is a fi rst choice for regional anesthesia considering its effectiveness, long duration and less motor blockade. Bupivacaine (S75-R25) is a mixture of optical isomers containing 75% levobupivacaine (S-) and 25% dextrobupivacaine (R+) created by a Brazilian pharmaceutical company. This investigation compared cardiac safety and efficacy of bupivacaine S75-R25 with vasoconstrictor and ropivacaine for brachial plexus blockade.

METHODS

Patients were randomized to receive brachial plexus anesthesia with either bupivacaine S75-R25 with epinephrine 1:200,000 (bupi) or ropivacaine (ropi), both at 0.50%, in 30 mL solution.We registered a continuous Holter ECG throughout the procedure, as well as the Lovett scale of force in addition to monitoring (heart rate, pulse oximetry and non-invasive blood pressure). The incidence of adverse events was compared with the chi-square or Fisher test.

RESULTS

We allocated forty-four patients into two groups. They did not show any difference related to age, weight or height, gender, as well as for surgical duration. Supraventricular arrhythmias were not different before or after the plexus blockade, independent of the local anestheticchosen. Loss of sensitivity was faster for the bupivacaine group (23.1 ± 11.7 min) compared to the ropivacaine one (26.8 ± 11.5 min), though not significant (p = 0.205, Student t). There was a reduction in the cardiac rate, observed during the twenty-four-hour Holter monitoring.

CONCLUSIONS

This study showed similar efficacy between bupivacaine S75-R25 for brachial plexus blockade and ropivacaine, with similar incidences of supraventricular arrhythmias.

MMP-1 promoter polymorphism is associated with primary tendinopathy of the posterior tibial tendon

Posterior tibial tendon (PTT) dysfunction is recognized as an etiology leading to acquired flatfoot in adults, causing significant functional loss. Many risk factors and systemic conditions have been proposed in literature. However, many patients present PTT dysfunction without any of these characteristics. This suggests that there could be a genetic influence associated with posterior tibial tendinopathy. The purpose of the present study is to investigate the association of the -1607 polymorphism in the promoter gene of MMP-1 and posterior tibial tendinopathy. The test group included 50 women, who presented PTT dysfunction grade 2 or 3, and who were submitted to surgical treatment, with histopathological examination of the tendon and magnetic resonance image (MRI) confirming tendinopathy, while the control group was 100 asymptomatic women who presented intact PTT at MRI. The results were analyzed using the chi-square test. The data showed a 75% incidence of the allele 1G and 62% of the genotype 1G/1G at the control group while, at the test group, they showed a 78% incidence of the allele 2G and 72% of the genotype 2G/2G (p < 0.001). The -1607 polymorphism of promoter gene of MMP-1 is associated with the posterior tibial tendinopathy in the studied population.

Pamidronate for the treatment of osteoporosis secondary to chronic cholestatic liver disease in Wistar rats

Osteoporosis is a major complication of chronic cholestatic liver disease (CCLD). We evaluated the efficacy of using disodium pamidronate (1.0 mg/kg body weight) for the prevention (Pr) or treatment (Tr) of cholestasis-induced osteoporosis in male Wistar rats: sham-operated (Sham = 12); bile duct-ligated (Bi = 15); bile duct-ligated animals previously treated with pamidronate before and 1 month after surgery (Pr = 9); bile duct-ligated animals treated with pamidronate 1 month after surgery (Tr = 9). Rats were sacrificed 8 weeks after surgery. Immunohistochemical expression of IGF-I and GH receptor was determined in the proximal growth plate cartilage of the left tibia. Histomorphometric analysis was performed in the right tibia and the right femur was used for biomechanical analysis. Bone material volume over tissue volume (BV/TV) was significantly affected by CCLD (Sham = 18.1 ± 3.2 vs Bi = 10.6 ± 2.2%) and pamidronate successfully increased bone volume. However, pamidronate administered in a preventive regimen presented no additional benefit on bone volume compared to secondary treatment (BV/TV: Pr = 39.4 ± 12.0; Tr = 41.2 ± 12.7%). Moreover, the force on the momentum of fracture was significantly reduced in Pr rats (Sham = 116.6 ± 23.0; Bi = 94.6 ± 33.8; Pr = 82.9 ± 22.8; Tr = 92.5 ± 29.5 N; P < 0.05, Sham vs Pr). Thus, CCLD had a significant impact on bone histomorphometric parameters and pamidronate was highly effective in increasing bone mass in CCLD; however, preventive therapy with pamidronate has no advantage regarding bone fragility.

Diagnosis of ovarian metastasis from gestational trophoblastic neoplasia by 3D power Doppler ultrasound and dynamic contrast-enhanced magnetic resonance imaging: case report

Choriocarcinoma is a highly malignant disease of trophoblastic cells, which affects young women in the reproductive years. The main sites of metastasis from choriocarcinoma are lung, vagina, liver, gastrointestinal tract and kidneys, and the involvement of the ovaries is extremely rare. The diagnosis of ovarian metastasis is made mainly by two-dimensional ultrasonography (2DUS) with color Doppler, which shows a large vessel in the center of the mass. The three-dimensional power Doppler ultrasound (3D power Doppler) and dynamic contrast-enhanced magnetic resonance imaging (MRI) are new diagnostic modalities not yet published in literature. We report a case of metastatic choriocarcinoma with left ovary involvement in a 48-year-old woman with history of molar pregnancy and irregular follow-up of this disease. We emphasize the main findings by 2DUS with color Doppler, 3D power Doppler and dynamic contrast-enhanced MRI. 3D power Doppler is able to improve the assessment of anatomical relationships of vessels with the ovarian mass, while the resonance angiography allows us to evaluate the anatomic relations of the mass and adjacent structures, as well as the iliac vessels. The 3D power Doppler and dynamic contrast-enhanced MRI are promising methods in the evaluation of metastasis arising from gestational trophoblastic tumors.

Outcomes of correction of internal hip rotation in patients with spastic cerebral palsy using proximal femoral osteotomy

Internal hip rotation (IHR) is the major cause of intoeing gait in patients with cerebral palsy (CP). Femoral derotation osteotomy (FDO) is the preferred treatment to correct excessive anteversion, however the condition may persist or recur postoperatively. Retrospective clinical and kinematic evaluation of 75 spastic diplegic CP patients was conducted for a mean duration of 22 months following proximal FDO. The patients were divided into two groups depending on the correction or persistence of IHR evident at kinematics after surgery. If corrected, mean patient follow-up was extended to 53 months. Outcomes were analyzed using Two Proportions Equality, Mann-Whitney and Wilcoxon tests. IHR persisted in 33.3% of cases at mean follow-up of 22 months and subtrochanteric femur osteotomy was more frequent in this group (p=0.033). Thirty-five of the fifty-four patients with first-round gait correction were monitored during the extended follow-up. Those for whom IHR recurred (9.5%) had undergone FDO at a comparatively younger age. Patient gender, operations prior to or at the time of femoral osteotomy, topographic classification, GMFCS level, or the extent of preoperative clinical and kinematic abnormalities had no apparent influence on persistence or recurrence of abnormal gait.

Interruption of a study of cervical ripening with isosorbide mononitrate due to adverse effects

PURPOSE OF INVESTIGATION

The objective of this study was to evaluate cervix length and the presence of cervical gland area (CGA) in ultrasounds performed before and after the administration of vaginal isosorbide mononitrate (IMN) for cervical ripening.

METHODS

We performed an observational, descriptive, and longitudinal study of pregnant patients indicated for labor induction and with a Modified Bishop Score (MBS) lower than six. For cervical ripening, 40 mg of vaginal IMN was administered at 0, 16, and 24 hours after the initiation of cervix preparation.

RESULTS

After enrolling 11 patients, the study had to be discontinued due to adverse effects. Three patients requested that they be withdrawn. Headaches were reported by all patients. Nausea, dizziness, dyspnea, and vomiting were also reported. The average cervical lengths at 0, 16, 24 and 36 hours were 27.6, 27.7, 25.9, and 23.0 mm, respectively. CGA disappeared in one of seven patients.

CONCLUSIONS

The use of IMN appears to increase the MBS, slightly reducing cervical length without altering the appearance of CGA. Considering the importance of maternal wellbeing during labor, the routine use of IMN cannot be recommended for cervical ripening in the third trimester due to the frequency and intensity of side-effects.

MICROSURGICAL TRANSFER OF THE GRACILIS MUSCLE FOR ELBOW FLEXION IN BRACHIAL PLEXUS INJURY IN ADULTS: RETROSPECTIVE STUDY OF EIGHT CASES

OBJECTIVE

Treating brachial plexus injuries is a major challenge, especially lesions that are presented late, with more than 12 months of evolution. We retrospectively analyzed patients who underwent one of the possibilities for attempting to restore the function of upper limbs affected under such conditions: microsurgical transfer of the gracilis muscle for elbow flexion.

METHODS

Eight patients were included, divided into two groups: one in which the procedure consisted of neurorrhaphy of the muscle flap with sural nerve grafting and anastomosis more distally; and the other, in which the neurorrhaphy was performed directly on the spinal accessory nerve, with anastomosis in thoracoacromial vessels.

RESULTS

We found a significant difference between the groups. A greater number of satisfactory results (75% M4) were found among patients who underwent direct neurorrhaphy, whereas the procedure using grafts for neurorrhaphy was less successful (25% M4).

CONCLUSION

Patients who underwent microsurgical functional transfer of the gracilis muscle in which vascular anastomoses were performed in thoracoacromial vessels presented better functional outcomes than shown by those whose anastomoses were in the brachial artery with subsequent use of a nerve graft.

Effect of neurotrophic factor, MDP, on rats' nerve regeneration

Our objective was to determine the immune-modulating effects of the neurotrophic factor N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) on median nerve regeneration in rats. We used male Wistar rats (120-140 days of age, weighing 250-332 g) and compared the results of three different techniques of nerve repair: 1) epineural neurorrhaphy using sutures alone (group S - 10 rats), 2) epineural neurorrhaphy using sutures plus fibrin tissue adhesive (FTA; group SF - 20 rats), and 3) sutures plus FTA, with MDP added to the FTA (group SFM - 20 rats). Functional assessments using the grasp test were performed weekly for 12 weeks to identify recovery of flexor muscle function in the fingers secondary to median nerve regeneration. Histological analysis was also utilized. The total number and diameter of myelinated fibers were determined in each proximal and distal nerve segment. Two indices, reported as percentage, were calculated from these parameters, namely, the regeneration index and the diameter change index. By the 8th week, superiority of group SFM over group S became apparent in the grasping test (P = 0.005). By the 12th week, rats that had received MDP were superior in the grasping test compared to both group S (P < 0.001) and group SF (P = 0.001). Moreover, group SF was better in the grasping test than group S (P = 0.014). However, no significant differences between groups were identified by histological analysis. In the present study, rats that had received MDP obtained better function, in the absence of any significant histological differences.

Effects of the association zidovudine plus ritonavir on the liver and kidneys of pregnant rats. Morphological and biochemical aspects

PURPOSE

To evaluate biochemical and morphological effects on rats submitted to three different doses of the association zidovudine and ritonavir administered throughout pregnancy.

METHODS

Forty pregnant EPM-1 Wistar rats weighing about 200 g were randomly divided into the control group (Ctr = drug vehicle control, n = 10) and three experimental ones which were treated with an oral solution of zidovudine/ritonavir (Exp1 = 10/20 mg/kg bw, n = 10; Exp2 = 30/60 mg/kg bw, n = 10; Exp3 = 90/180 mg/kg bw, n = 10) from 'day 0' up to the 20th day of pregnancy. At term (20th day) the rats were anesthetized. Blood and fetal and maternal organ samples (livers and kidneys) were taken for morphological and biochemical analyses.

RESULTS

Upon histological examinations fetal livers and kidneys appeared normal. In contrast the maternal samples revealed structural alterations. Maternal kidneys of the three experimental groups exhibited progressive and dose-dependent histological alterations; liver alterations were detected only in Exp3. Blood levels of AST and ALT were not significantly different from the control group but urea and creatinine levels were lower in groups Exp3 and Exp1.

CONCLUSIONS

The administration of zidovudine plus ritonavir throughout rat pregnancy can cause morphological as well as functional changes in maternal kidneys.

Comparison between proximal row carpectomy and four-corner fusion for treating osteoarthrosis following carpal trauma: a prospective randomized study

OBJECTIVE

To compare the functional results of carpectomy and four-corner fusion surgical procedures for treating osteoarthrosis following carpal trauma.

METHODS

In this prospective randomized study, 20 patients underwent proximal row carpectomy or four-corner fusion to treat wrist arthritis and their functional results were compared. The midcarpal joint was free of lesions in all patients.

RESULTS

Both proximal row carpectomy and four-corner fusion reduced the pain. All patients had a decreased range of motion after surgery. The differences between groups were not statistically significant.

CONCLUSIONS

Functional results of the two procedures were similar as both reduced pain in patients with scapholunate advanced collapse/scaphoid non-union advanced collapse (SLAC/SNAC) wrist without degenerative changes in the midcarpal joint.

Vascularized bone grafts for upper limb reconstruction: defects at the distal radius, wrist, and hand

Vascularized bone grafts have been successfully applied for the reconstruction of bone defects at the forearm, distal radius, carpus, and hand. Vascularized bone grafts are most commonly used in revision cases in which other approaches have failed. Vascularized bone grafts can be obtained from a variety of donor sites, including the fibula, the iliac crest, the distal radius (corticocancellous segments and vascularized periosteum), the metacarpals and metatarsals, and the medial femoral condyle (corticoperiosteal flaps). Their vascularity is preserved as either pedicled autografts or free flaps to carry the optimum biological potential to enhance union. The grafts can also be transferred as composite tissue flaps to reconstruct compound tissue defects. Selection of the most appropriate donor flap site is multifactorial. Considerations include size matching between donor and defect, the structural characteristics of the graft, the mechanical demands of the defect, proximity to the donor area, the need for an anastomosis, the duration of the procedure, and the donor site morbidity. This article focuses on defects of the distal radius, the wrist, and the hand.

Anterograde removal of broken femoral nails without opening the nonunion site: a new technique

OBJECTIVE

We describe a new technique for removing the distal fragments of broken intramedullary femoral nails without disturbing the nonunion site.

METHODS

This technique involves the application of an AO distractor prior to the removal of the nail fragments, with subsequent removal of the proximal nail fragment in an anterograde fashion and removal of the distal fragment through a medial parapatellar approach. Impaction of the fracture site is then performed with a nail that is broader than the remaining fragmented material.

RESULTS

Nails were removed from five patients using the technique described above without any complications. After a mean follow-up period of 61.8 months, none of these patients showed worsened knee osteoarthritis.

CONCLUSION

The original technique described in this article allows surgeons to remove the distal fragment of fractured femoral intramedullary nails without opening the nonunion focus or using special surgical instruments.