An evaluation of the use of retrospectively acquired preoperative AOFAS clinical rating scores to assess surgical outcome after elective foot and ankle surgery

The use of retrospectively acquired preoperative AOFAS rating scores in clinical research to assess the outcomes of elective foot and ankle surgery has not been validated. The data obtained utilizing this methodology may misrepresent the results and lead to spurious conclusions. This investigation compared preoperative AOFAS Ankle-Hindfoot scores obtained before and after surgery from patients who had undergone elective surgery to determine if retrospectively acquired scores match those collected prospectively. Only two out of 47 patients (4%) recalled identical AOFAS scores. The mean difference between the preoperative scores (preoperative score obtained after surgery minus preoperative score obtained before surgery) was -5.3 points. Fifteen patients (32%) had preoperative scores that differed by 20 points or more. Kappa statistics found little agreement among the five elements that comprised the two preoperative scores when responses obtained before and after surgery were compared to one another. The results suggest that preoperative clinical rating scores obtained after elective surgery are a poor predictor of the patient's preoperative condition and that studies which employ retrospectively acquired preoperative AOFAS clinical rating scores may overestimate the benefit of surgery.     

Glomerular complement regulation is overwhelmed in passive Heymann nephritis

BACKGROUND: An injection of anti-Fx1A antibodies in rats leads to passive Heymann nephritis (PHN), a model of membranous nephropathy. Fx1A is a crude extract of renal cortex that contains megalin as a principal component. However, when rats are given anti-megalin antibodies, abnormal proteinuria does not occur. Because of the established complement dependence of PHN, we hypothesized that antibodies neutralizing complement regulatory proteins in the rat glomerulus also were required to induce PHN. Two likely targets are Crry and CD59, proteins abundant on the rat podocyte and contained within Fx1A that inhibit the C3 convertase and C5b-9 assembly, respectively. METHODS: Rats were injected with anti-megalin monoclonal antibodies, followed by anti-Crry and/or anti-CD59 F(ab')(2) antibodies five days later. In a second group of experiments, rats were injected with anti-Fx1A or anti-Fx1A immunodepleted of reactivity against Crry and/or CD59. RESULTS: In the setting of podocyte-associated anti-megalin monoclonal antibodies, simultaneous neutralization of Crry and CD59 function led to the development of significant proteinuria (11.0 +/- 2.1 mg/day, P < 0.001 vs. all other groups). In contrast, animals that had neither or only one of these complement regulators inhibited had normal urinary protein excretion (< or =6 mg/day). In animals given anti-Fx1A depleted of anti-Crry and/or anti-CD59, all groups developed typical PHN, characterized by heavy proteinuria and extensive glomerular deposition of C3 and C5b-9. CONCLUSION: Crry and CD59 play an important role in restraining complement-mediated injury following subepithelial immune complex deposition; however, in PHN, their regulatory capacity is overwhelmed.     

Influence of a platelet concentrate on prosthetic bone ingrowth in a rabbit model

Recent studies have shown that an increase in bone ingrowth by addition of osteogenic growth factors can reduce micro motion and gross implant motion and contribute to joint implant stability through osseointegration. Platelet-rich plasma (PRP) has the potential to provide growth factors that may be conducive to osteointegration at the bone-implant interface. This study analyzed the influence of PRP on bone ingrowth upon a beaded metal implant in distal femurs of 22 rabbits. Rabbit limbs were randomly assigned to receive an implant plus PRP or plain implant. Half of the specimens were randomly assigned to a 2-week group (n = 20) or a 5-week group (n = 20). Histologic and histomorphometric comparison between implant alone and implant plus PRP, at 2 and 5 weeks, was performed. In both the 2- and 5-week comparisons, there was no statistical difference (p > .05) in bone ingrowth between the control and PRP group, despite a slight increase in trabecular bone growth in PRP groups. This study suggests that PRP is not a major contributing factor to bone ingrowth at the bone-implant interface. This supports growing evidence in the literature that PRP can lead to variable bone growth stimulation in vivo.     

Association of Hypoalbuminemia on the First Postoperative Day and Complications Following Esophagectomy

Objective Changes in serum albumin may reflect systemic immunoinflammation and hypermetabolism in response to insults such as trauma and sepsis. Esophagectomy is associated with a major metabolic stress, and the aim of this study was to determine if the absolute albumin level on the first postoperative day was of value in predicting in-hospital complications. Methods A retrospective study of 200 patients undergoing esophagectomy for malignant disease at St. James Hospital between 1999 and 2005 was performed. Patients who had pre and postoperative (days 1, 3, and 7) serum albumin levels measured were included in the study. Patients were subdivided into three postoperative albumin categories <20 g/l, 20–25 g/l, >25 g/l. Logistic regression analysis was performed to calculate the odds of morbidity and mortality according to the day 1 albumin level. Results Patients with an albumin of less than 20 g/l on the first postoperative day were twice as likely to develop postoperative complications than those with an albumin of greater than 20 g/l (54 vs 28% respectively, p < 0.011). Correspondingly, these patients also had a significantly higher rate of Adult Respiratory Distress Syndrome (22 vs 5%, p < 0.001), respiratory failure (27 vs 8%, p < 0.01) and in-hospital mortality (27 vs 6% (p < 0.001). On multivariate logistic regression analysis, day 1 albumin level was independently related to postoperative complications (odds ratios, 0.89: 95%; confidence intervals, 0.83–0.96; p < 0.005). In addition, albumin <20 g/l on the first postoperative day was associated with the need for further surgery and a return to ICU. Conclusion Serum albumin concentration on the first postoperative day is a better predictor of surgical outcome than many other preoperative risk factors. It is a low cost test that may be used as a prognostic tool to detect the risk of adverse surgical outcomes.     

Partially Overlapping Limited Anterior and Posterior Instrumentation for Adult Thoracolumbar and Lumbar Scoliosis: A Description of Novel Spinal Instrumentation, “The Hybrid Technique”

Progressive and/or painful adult spinal deformity in the thoracolumbar and lumbar spine is sometimes treated surgically by long posterior fusions from the thoracic spine down to the pelvis, especially where there is a major thoracic curve component. Recent advances in anterior spinal instrumentation and spinal surgery technique have demonstrated the improved corrective ability offered by anterior stabilization systems, and the added benefit of limiting the number of vertebral fusion levels required for control of the deformity. The "hybrid technique" is a novel use of anterior instrumentation that applies limited anterior instrumentation down to the low lumbar spine (rods and screws), and partially overlapping short-segment posterior instrumentation to the sacrum (pedicle screws and rods). These constructs avoid posterior thoracic instrumentation and fusions, and avoid extension of posterior instrumentation to the pelvis. In the first 10 patients treated using this technique, thoracolumbar and lumbar major curve correction has averaged 71 and 82% in the immediate postoperative period (n = 7), respectively, and 59 and 68% at 2-year follow-up, respectively. The technique is an appealing and attractive alternative for treatment of thoracolumbar and lumbar scoliosis in the adult population, and avoids the requirement for applying spinal fixation to the thoracic spine and the pelvis.     

Endoscopic instrumented posterolateral lumbar fusion with Healos and recombinant human growth/differentiation factor-5

OBJECTIVE: The goal of this study was to use a minimally invasive endoscopic surgical technique in a sheep model to evaluate the efficacy of an osteoinductive growth factor, recombinant human growth/differentiation factor-5 (also designated MP52), and an osteoconductive matrix formulation (Healos; DePuy AcroMed, Inc., Mountain View, CA) for inducing and facilitating bone formation. METHODS: Twelve mature sheep underwent bilateral posterolateral lumbar fusion and pedicle screw fixation via a posterior endoscopic approach. Each sheep received two different types of graft material, autogenous iliac crest bone, or a bone graft substitute (MP52 with Healos), inserted into the right and left sides of the spine in an alternating fashion. Groups of four sheep were killed at 2, 4, and 6 months postoperatively for manual, radiographic, and histological evaluation. RESULTS: No neurological impairments, infections, or other complications were observed. After 2 months, partial fusion on both sides was observed, but radiographic evaluation showed greater bone growth on the side that received the bone graft substitute. Solid posterolateral fusion was observed in both autograft and bone graft substitute sites at 4 and 6 months, and autograft and Healos MP52 fusion sites were essentially the same at histological examination. There was no abnormal overgrowth of new bone from either of these two materials. CONCLUSION: Endoscopic posterolateral lumbar arthrodesis and instrumentation is feasible, safe, and effective in a sheep model. Healos is a useful bonding agent that mimics natural bone in posterolateral intertransverse fusion sites. Combined with MP52, it produced fusion comparable to that of autogenous bone graft. Minimally invasive techniques and bone graft substitutes could eliminate morbidity and increase the likelihood of successful fusion.     

Postoperative infection in cochlear implant patients.

OBJECTIVE: Recently, the association of meningitis with cochlear implants has raised concern over the safety of these devices. We examined the incidence of all postoperative infections in patients undergoing cochlear implant surgery.Study design and settings A retrospective chart review of all patients undergoing cochlear implants at a private tertiary referral center from 1993 to 2002 was performed. Cochlear implant surgeries in 462 adults and 271 children were reviewed. Patients with evidence of a postoperative infection or infectious complication related to cochlear implantation were identified, and data on patient characteristics, surgery, and treatment outcome were obtained. RESULTS: The overall incidence of postoperative infection in our cochlear implant series was 4.1%. Major infectious complications occurred in 3.0% of cases, and the majority of infections required surgical intervention. A history of chronic ear disease may increase the risk of infectious complications. There were no cases of meningitis. CONCLUSIONS: Cochlear implants remain a safe procedure with a low complication rate. The majority of infections can be managed without removing the implant device. Advances in surgical technique and flap design have decreased the occurrence of wound-related complications. However, identification of risk factors for infection and optimization of treatment regimens will further reduce the complications associated with postoperative infection.     

Isolation of a cDNA clone for the liver cell adhesion molecule (L-CAM).

Liver cell adhesion molecule (L-CAM) is a calcium-dependent cell adhesion molecule found in very early vertebrate embryos and on liver and other epithelial cells in adults. To describe the genes coding for the molecule and study its synthesis, we have cloned cDNA from poly(A)+ RNA of 10-day embryonic chicken liver using the delta gt11 expression vector. One clone, lambda L301, has been characterized and used in analyses of L-CAM mRNA and genomic DNA. Clone lambda L301 produced a fusion protein that reacted strongly with polyclonal antibodies that recognize L-CAM (Mr 124,000) and its Mr 81,000 NH2-terminal fragment, Ft1, released from liver membranes by trypsin. This result indicates that lambda L301 contains a cDNA insert complementary to protein coding sequence within the two-thirds of the mRNA coding region beginning at the 5' end. The 220-base-pair cDNA insert was isolated and used as a probe in hybridization experiments. RNA transfer blot analysis of poly(A)+ RNA showed a single 4-kilobase mRNA; Southern blot analysis showed multiple components consistent with the presence of one to three L-CAM genes. To test whether different tissues express different forms of L-CAM message, poly(A)+ RNA from eight embryonic organs was analyzed. Only organs that expressed L-CAM protein contained poly(A)+ RNA that hybridized to the lambda L301 probe; in all cases a single band, with the same mobility as that in liver, was observed. The L-CAM mRNA in each tissue was present in proportions similar to those detected previously for the L-CAM protein in these tissues. The combined results suggest that any possible heterogeneity in the L-CAM genes is not reflected in the size of either the mRNA or protein.     

Isolation and point of action of a factor from Escherichia coli required to reconstruct translation.

To study the mechanism of translation we have attempted to reconstruct the process from purified components. Protein synthesis was programmed by the RNAs of wild-type or amber mutants of bacteriophages f2 or MS2. Translation programmed by MS2 or f2am3 RNA does not occur using ribosomes, precharged aminoacyl-tRNAs, and the sum of the purified proteins involved in initiation (initiation factors; IF-1, IF-2, and IF-3), propagation (elongation factors; EF-Tu, EF-Ts, and EF-G) and termination (release factors; RF-1 or RF-2) of protein synthesis. The requirement for a protein called W was demonstrated. Protein W was purified free of all translation factors, activating enzymes, and other proteins such as the RR, "rescue," and EF-P implicated in translation. The stimulation of propagation by W depended on the position of the amino acid residue to be added in the synthesis of the NH2-terminal hexapeptide of the coat protein. In the reconstructed system, with the sum of all translation factors but in the absence of W, only dipeptides and smaller quantities of tripeptides were synthesized under the direction of f2am3 RNA. W stimulated the synthesis of the hexapeptide, fMet-Ala-Ser-AspNH2-Phe-Thr directed by this RNA. In addition, W stimulated ejection of non-cognate tRNAs that bind to ribosomal particles.