Intermediate follow-up following intravascular stenting for treatment of coarctation of the aorta.

BACKGROUND: We report a multiinstitutional study on intermediate-term outcome of intravascular stenting for treatment of coarctation of the aorta using integrated arch imaging (IAI) techniques. METHODS AND RESULTS: Medical records of 578 patients from 17 institutions were reviewed. A total of 588 procedures were performed between May 1989 and Aug 2005. About 27% (160/588) procedures were followed up by further IAI of their aorta (MRI/CT/repeat cardiac catheterization) after initial stent procedures. Abnormal imaging studies included: the presence of dissection or aneurysm formation, stent fracture, or the presence of reobstruction within the stent (instent restenosis or significant intimal build-up within the stent). Forty-one abnormal imaging studies were reported in the intermediate follow-up at median 12 months (0.5-92 months). Smaller postintervention of the aorta (CoA) diameter and an increased persistent systolic pressure gradient were associated with encountering abnormal follow-up imaging studies. Aortic wall abnormalities included dissections (n = 5) and aneurysm (n = 13). The risk of encountering aortic wall abnormalities increased with larger percent increase in CoA diameter poststent implant, increasing balloon/coarc ratio, and performing prestent angioplasty. Stent restenosis was observed in 5/6 parts encountering stent fracture and neointimal buildup (n = 16). Small CoA diameter poststent implant and increased poststent residual pressure gradient increased the likelihood of encountering instent restenosis at intermediate follow-up. CONCLUSIONS: Abnormalities were observed at intermediate follow-up following IS placement for treatment of native and recurrent coarctation of the aorta. Not exceeding a balloon:coarctation ratio of 3.5 and avoidance of prestent angioplasty decreased the likelihood of encountering an abnormal follow-up imaging study in patients undergoing intravascular stent placement for the treatment of coarctation of the aorta. We recommend IAI for all patients undergoing IS placement for treatment of CoA.     

Autoradiographic evaluation of circadian periodicity in cell proliferation in the periodontal ligament of the young mouse

Five-week-old BNL male mice were maintained on a 12-h light/dark cycle, subcutaneously injected with [3H]-thymidine 1 h before death and killed every 3 h for 24 h. Autoradiographs were made from demineralized, paraffin-wax embedded sagittal sections of maxillae. The labelling index was calculated for fibroblast-like cells of the periodontal ligament mesial to the first molar. A bimodal distribution of labelled cells was seen. Labelling index was highest at 0900 h (light period); a second, lower, peak was seen at 2400 h (dark period). Cell proliferation was significantly increased during the light period. The increased activity during the dark period may represent a superimposed secondary, ultradian, rhythm, differences in periodontal cell subtypes or may be related to the feeding and activity cycle of the mouse. Thus there is a 24-h cyclic rhythmicity in the proliferation of periodontal-ligament cells in the mouse.     

Gene therapy for spinal applications

Gene therapy is a promising drug delivery mechanism for the treatment of spinal disorders. Currently, the technique has been most useful in enhancing growth factor therapy for spinal fusion, intervertebral disc regeneration, and spinal cord injury healing. Gene therapy allows for the high-level local production of growth factors, obviating the need for slow release carriers or continuous infusion pumps that are otherwise necessary because of the short half-lives of most peptide growth factors. Although continuous expression is desirable, growth factor therapy is usually intended to be transient. The typical expression profile of Ad vectors--at a high level over 2 weeks or so--has been ideal, leading to its widespread use in these applications. Despite the ability of Ad to deliver genes directly in vivo, however, the cell-based ex vivo approach has been used widely in spinal applications. In spinal cord injury, cells such as peripheral nerve or Schwann cells may provide a permissive substrate for axonal growth [51]. For spinal fusion and IVD regeneration, ex vivo manipulation of cells facilitates gene transfer, because bone and IVD tissue are too dense to be penetrated by injection of Ad or other vectors. The use of cells may be advantageous in these applications in which new tissue formation is the goal. Finally, the use of genetically modified cells may decrease the inflammatory reaction induced by Ad vectors. Although gene therapy for spinal disorders has been centered around Ad-mediated transfer of single growth factor genes, the options for candidate genes and vectors are growing rapidly. Ad vectors are being improved by decreasing their immunogenicity and altering their tropism [2]. Vectors based on other viruses (such as herpes, adeno-associated virus, and lentivirus) are being developed, also with lower immunogenicity and with longer durations of expression [26,67]. Regulated expression, such as with the tetracycline regulated promoter, is being developed so that genes can be turned on or off as needed. Such regulation may be sensitive even to physiologic cues in the future [68,69]. Finally, the high throughput technologies, such as the gene chip, are elucidating thousands of genes that may be good candidates for the enhancement of bone healing and IVD and spinal cord regeneration. Genes whose products not only support bone, fibrocartilage, or axon growth but also neutralize natural inhibitors or promote tissue remodeling and maturation may be good future candidates. In the future, a series of vectors with multiple genes that are regulated by physiologic cues might be used to enhance spinal fusion, restore IVD tissue, or support spinal cord healing.     

Current concepts in intervertebral disc restoration

A current focus of treatment for degenerative disk disease is the restoration of the intervertebral disk. This article summarizes the structure and function of the intervertebral disk, the pathogenesis of its degeneration, and the clinical relevance of degenerative disk disease. Current literature relating to intervertebral disk replacement and regeneration is reviewed.     

Incidental durotomy in spine surgery

STUDY DESIGN: Retrospective review of a large series of patients who underwent spinal surgery at a single institution during a 10-year period. OBJECTIVES: To further clarify the frequency of incidental durotomy during spine surgery, its treatment, associated complications, and results of long-term clinical follow-up. SUMMARY OF BACKGROUND DATA: Incidental durotomy is a relatively common occurrence during spinal surgery. There remains significant concern about it despite reports of good associated clinical outcomes. There have been few large clinical series on the subject. METHODS: A retrospective review was conducted of clinical and surgical records and radiographic data for consecutive patients who underwent spinal surgery performed by the two senior surgeons from January 1989 through December 1998. RESULTS: A total of 2144 patients were reviewed, and 74 were found to have dural tears occurring during or before surgery. Incidental durotomy occurred at the time of surgery in 66 patients (3.1% overall incidence). Incidence varied according to the specific procedure performed but was highest in the group that underwent revision surgery. The incidence of clinically significant durotomies occurring during surgery but not identified at the time was 0.28%. All dural tears that occurred during surgery and were recognized (60 of 66) were repaired primarily. Pseudomeningoceles developed in five of the remaining six patients. All six patients had subsequent surgical repair of dural defects because of failure of conservative therapy. A mean follow-up of 22.4 months was available and showed good long-term clinical results for all patients. CONCLUSIONS: Incidental durotomy, if recognized and treated appropriately, does not lead to long-term sequelae.     

A multidisciplinary audit of clinical coding accuracy in otolaryngology: financial,managerial and clinical governance considerations under payment‐by‐results

Objectives: To audit the accuracy of otolaryngology clinical coding and identify ways of improving it. Design: Prospective multidisciplinary audit, using the ‘national standard clinical coding audit’ methodology supplemented by ‘double‐reading and arbitration’. Settings: Teaching‐hospital otolaryngology and clinical coding departments. Participants: Otolaryngology inpatient and day‐surgery cases. Main outcome measures: Concordance between initial coding performed by a coder (first cycle) and final coding by a clinician‐coder multidisciplinary team (MDT; second cycle) for primary and secondary diagnoses and procedures, and Health Resource Groupings (HRG) assignment. Results: 1250 randomly‐selected cases were studied. Coding errors occurred in 24.1% of cases (301/1250). The clinician‐coder MDT reassigned 48 primary diagnoses and 186 primary procedures and identified a further 209 initially‐missed secondary diagnoses and procedures. In 203 cases, patient’s initial HRG changed. Incorrect coding caused an average revenue loss of £174.⁹⁰ per patient (14.7%) of which 60% of the total income variance was due to miscoding of a eight highly‐complex head and neck cancer cases. The ‘HRG drift’ created the appearance of disproportionate resource utilisation when treating ‘simple’ cases. At our institution the total cost of maintaining a clinician‐coder MDT was 4.8 times lower than the income regained through the double‐reading process. Conclusions: This large audit of otolaryngology practice identifies a large degree of error in coding on discharge. This leads to significant loss of departmental revenue, and given that the same data is used for benchmarking and for making decisions about resource allocation, it distorts the picture of clinical practice. These can be rectified through implementing a cost‐effective clinician‐coder double‐reading multidisciplinary team as part of a data‐assurance clinical governance framework which we recommend should be established in hospitals.