Revision anterior cruciate ligament reconstruction using a 2-stage technique with bone grafting of the tibial tunnel

BACKGROUND: Revision anterior cruciate ligament surgery is often considered a salvage procedure with limited goals. However, this limitation need not be the case. Similar to primary reconstruction, the goal should be to choose an appropriate graft and place it in an anatomical position in a good quality bone. The issue of good quality bone seems to have been ignored. HYPOTHESIS: A 2-stage anterior cruciate ligament revision reconstruction with bone grafting of the tibial tunnel and the use of a different femoral tunnel will produce measured knee laxity and International Knee Documentation Committee scores similar to a primary anterior cruciate ligament reconstruction. STUDY DESIGN: Case control study; Level of evidence, 3. METHODS: This prospective study involved 49 consecutive 2-stage anterior cruciate ligament revisions (group R) performed by a single surgeon from 1993 to 2000. Two-stage revision surgery was performed if the tibial tunnel from a previous reconstruction surgery would overlap (either partially or fully) the correctly placed revision tunnel. The first stage consisted of removal of the old graft and interfering metalwork, together with bone grafting of the tibial tunnel. After ensuring adequate bone graft incorporation using computed tomography scan, the second stage revision was undertaken. This stage comprised harvesting the autograft, its anatomical placement, and its adequate fixation. The results were compared with the results of a matched group of patients with primary anterior cruciate ligament reconstruction (group P). RESULTS: In group R, as meniscal and chondral lesions were more common, the International Knee Documentation Committee scores were lower than those of group P (61.2 for group R and 72.8 for group P; P = .006). Objective laxity measurement was similar in both groups (1.36 mm for group R and 1.2 mm for group P; P = .25). CONCLUSION: This study establishes that the laxity measurements achieved with a 2-stage revision anterior cruciate ligament reconstruction can be similar to those achieved after primary anterior cruciate ligament reconstruction, although the International Knee Documentation Committee rating is lower.     

Management of scrotal swelling after pelvic and acetabular fractures

Complex pelvic and acetabular fractures are usually associated with high-energy trauma and often present with substantial perineal soft tissue swelling. This is the result of the significant haemorrhage that develops into the retroperitoneal space, which dissects along fascial planes to extend into the scrotum. Other factors that could contribute to the progression of the soft tissue swelling include the extensive approaches used for surgical stabilization of the fractures, the prolonged traction using a perineal post and the early typical catabolic responses after major trauma. This article describes a successful protocol for the management of scrotal swelling associated with complex pelvic and acetabular fractures. Rapid reduction of the swelling in the scrotal region prevents the onset of perineal wound slough. It also minimizes the risk of infection in case of skin breakdown by isolation from the perianal region. Furthermore, it precludes friction of the scrotum with the skin of the thigh, thus allowing adequate pain relief and faster rehabilitation.     

Systemic effects of bilateral tibial versus bilateral femoral shaft fractures. Is there a difference?

The authors investigated the prevalence and the difference in the severity of systemic complications following intramedullary nailing of bilateral tibial and femoral shaft fractures. A retrospective chart analysis of 12 consecutive patients with bilateral tibial shaft fractures (TF) and 14 patients with bilateral femoral shaft fractures (FF) was performed. The incidences of bilateral tibial fractures and bilateral femoral shaft fractures were 3.8% and 4.6% respectively. The median Injury Severity Score (ISS) in TF group was 13 (9-29) compared to 16 (9-34) in the FF group (p = 0.169). The mean resuscitation requirements were 4.2 (3-11) litres of colloids and crystalloids and 1.7 (0-10) units of blood in the TF group and 10.6 (6-16) litres of colloids and crystalloids and 9.2 (5-25) units of blood in the FF group (p = 0.002). In the TF group there was 1 death compared to 2 in the FF group. In the TF group, there were 2 cases of ARDS, 4 cases of deep sepsis and 3 above knee amputations. In the FF group, there were 6 cases of ARDS (p = 0.04), 1 case of deep sepsis and 1 above knee amputation. Patients with bilateral tibial shaft fractures revealed lower ISS, resuscitation requirements, ARDS, associated injuries, and mortality when compared to bilateral femoral shaft fractures. This is probably due to the anatomical difference in the morphology of the bones, volume of liberated intravascular marrow fat, organisation and layout of the venous capillary network and severity of associated injuries.     

Isoflurane alters the amount of dopamine transporter expressed on the plasma membrane in humans

BACKGROUND: Isoflurane increases extracellular dopamine concentration and causes trafficking of the dopamine transporter (DAT) in transfected cells. Also, the binding potentials of highly specific positron-emitting DAT ligands are altered by isoflurane in rhesus monkeys. The purpose of this study was to determine the dose-response curve for isoflurane altering the binding potential of one of these ligands ([F-18]FECNT) in humans. METHODS: Twenty human volunteers underwent positron emission tomography using [F-18]FECNT. All subjects were scanned while awake and then again after assignment to one of four groups (n = 5 each): awake-control, propofol-control, or light or deep isoflurane anesthesia as defined by Bispectral Index monitoring. Bispectral Index values in the light anesthesia group were 40 +/- 7 (end-tidal isoflurane, 1.02 +/- 0.08) versus 27 +/- 10 (end-tidal isoflurane, 1.6 +/- 0.3) in the deep anesthesia group. The within-subject percent change in putamen binding potential between the awake and second scans was determined for each subject, averaged within groups, and compared across groups. RESULTS: The [F-18]FECNT binding potential exhibited a biphasic shape as a function of anesthetic dose. The binding potential for the second scan in the awake-control and propofol-control groups was significantly less than the initial scan; for the light anesthesia group, the binding potential was significantly increased during anesthesia, and no change was detected between the two scans in the deeper anesthesia group. CONCLUSION: Isoflurane causes a dose-dependent change in the [F-18]FECNT binding potential for DAT consistent with isoflurane causing trafficking of the DAT between the plasma membrane and the cell interior. Concentrations of isoflurane below minimum alveolar concentration causes DAT to be trafficked to the plasma membrane from the cell interior, but no net trafficking occurs at higher concentrations. The data are most easily explained if isoflurane alters the amount of functionally expressed DAT through an indirect pathway. This phenomena should be more fully explored to help make the next generation of anesthetics more mechanistically specific and to reduce undesired side effects.     

Transient focal cerebral ischemia-induced neurogenesis in the dentate gyrus of the adult mouse

OBJECT: Throughout the life of a mammal, new neurons are produced each day from resident progenitor cells located in the hippocampal dentate gyrus (DG). The availability of transgenic and knockout mice enables the evaluation of specific molecular mediators of this phenomenon. To facilitate such studies the authors characterized the proliferation, survival, and maturation of progenitor cells in the DG of adult mice following transient focal cerebral ischemia. METHODS: Anesthesia was induced in adult C57BL/6 mice by administering halothane. The middle cerebral artery (MCA) was then occluded for 120 minutes by applying an endovascular suture. The marker used to detect the presence of proliferating cells, 5-bromodeoxyuridine (BrdU; 50 mg/kg) was administered intraperitoneally twice daily on Days 2 through 6 after the MCA occlusion. Cohorts of mice were killed on Days 7 and 21, after which their brains were sectioned and BrdU-positive cells were detected using immunohistochemical analysis. The phenotype of the BrdU-positive cells was identified by fluorescent triple labeling by using antibodies specific for neuronal and astroglial markers together with anti-BrdU antibodies. The infarction was confirmed by applying cresyl violet staining. Compared with sham-operated control animals, there was a 4.6-fold (p < 0.05) increase in BrdU-positive cells in the ipsilateral DG at Day 7 postischemia. Twenty-one percent of the newly proliferated cells survived to Day 21 postischemia. At this time, the newly proliferated cells expressed the immature and mature neuron markers doublecortin and NeuN, respectively, but none expressed the astroglial marker glial fibrillary acidic protein. CONCLUSIONS: Focal ischemia induces neurogenesis in the DG of the mouse brain; this may be critical for postischemic brain repair.     

Unruptured intracranial aneurysms: benign curiosity or ticking bomb?

15 years ago, the treatment of incidentally discovered intracranial aneurysms was straightforward with a good evidence base behind it. When intracranial aneurysms were identified, people were referred to neurosurgeons who would offer surgical repair if the patient was in reasonable health and had a good life expectancy. Since that time, several studies have given contradictory evidence for what should be done with these lesions, and a new technique for the repair of aneurysms, endovascular coil embolisation, has been developed. Here we review the research and make several recommendations. First, incidentally discovered aneurysms in the anterior circulation less than 7 mm in size in people with no personal or family history of subarachnoid haemorrhage should be left untreated. Second, people with remaining life expectancy of less than 20 years or so (ie, those over age 60 years) should be informed that from a statistical point of view the benefits of treatment do not outweigh the risks. Third, in all other cases treatment with surgical clipping or coil embolisation should be advised. And finally, if surgical treatment is not feasible then medical hypotensive treatment may be a viable alternative.     

The cytotoxic activity of the total alkaloids isolated from different parts of Solanum pseudocapsicum

The total alkaloid fractions of the methanolic extracts of the leaves, ripe fruits, roots, seeds and stem of Solanum pseudocapsicum were subjected to in-vitro cytotoxicity, short-term toxicity and long-term survival studies. All the five fractions exhibited potent activity. The total alkaloid fraction of leaves was found to be the most potent. The HT-29 cell line was the most sensitive to the fractions. The cytotoxic concentration (CTC(50)) values for all these fractions ranged between 0.39-0.91, 0.68-2.8, 0.92-3.56, 4.05-8.2, 3.28-5.65 and 0.95-5.55 microg/ml, respectively for HT-29, RD-228, A-549, HEp-2, B(16)F(10) and Vero cell lines. In short-term toxicity studies, the fractions showed 50% viability at 93-128 microg/ml for DLA cells and 141-189 microg/ml for human lymphocytes. In the long-term survival studies on the cell lines RD-228, HEp-2 and Vero, cells retained their regenerative capacities at concentrations below 8 microg/ml. The total alkaloids of the plant, especially from the leaves merit further investigations to identify the active constituents in animal models.     

Dexamethasone regulates endothelin-1 and endothelin receptors in human non-pigmented ciliary epithelial (HNPE) cells

Endothelin-1 (ET-1) lowers intraocular pressure (IOP) in animal models by regulating aqueous humour dynamics through both inflow and outflow mechanisms. Moreover, ET's concentration is elevated in glaucoma patients and in animal models of glaucoma. Glucocorticoid therapy often can lead to increase IOP in susceptible individuals including patients with primary open angle glaucoma (POAG). In this study, we examined the effects of dexamethasone (Dex), a frequently used anti-inflammatory glucocorticoid, on the synthesis and release of endothelin-1 and on the expression of endothelin receptors in human non-pigmented ciliary epithelial (HNPE) cells, an established source for ET-1 in the anterior chamber. As measured by ET-1 immunoreactivity, ET-1 was concentration-dependently increased following 24hr Dex treatment, with a maximum concentration (100 nM) causing a threefold increase of ET-1 release. Western blot analysis of HNPE cells showed the expression of endothelin receptor A (ET(A)) and endothelin receptor B (ET(B)) with approximate molecular weights of 40 kDa. Dex treatment decreased ET(A) receptor expression at all Dex doses, but up-regulated ET(B) receptors with 10nM Dex having the greatest effect. Quantitative PCR demonstrated that Dex also increased the mRNA of pre-pro-ET-1 (ppET-1) and ET(B) but decreased the mRNA of ET(A). RU486, a glucocorticoid receptor antagonist, was able to block Dex's actions on ET release and ET(B) receptor expression, but did not block its action on ET(A) receptor expression. Endothelin receptors were minimally expressed in HNPE cells as determined in binding experiments (B(max): ET(A) 17, ET(B) 25 fmolmg(-1) membrane protein). However Dex treatment stimulated a dramatic increase in ET(B) receptor density while decreasing ET(A) receptors (B(max): ET(A) 11, ET(B) 116 fmolmg(-1) membrane protein). The regulation of endothelin and its receptors could be a novel mechanism associated with glucocorticoid's effects on intraocular pressure. The increase in ET-1 and disproportionate regulation in ET receptor expression by Dex could promote dysregulation in ET's mechanism on both inflow and outflow, thus affecting aqueous humour dynamics in the anterior chamber of the eye.